Motor vehicle door with a detachably mounted outside door panel

A motor vehicle door with a door frame (1) and with an outside door panel (2) which can be attached to the door frame (1). The door frame (1) has an undercut guide groove (10) on a first edge and on a second edge which is roughly opposite the first edge. The outside door panel (2), on its first and second edge, has undercut guide rails (12) which fit into the guide grooves (10). The door frame (1) on a third edge which runs roughly transversely to the first and second edge has a retaining groove and on the fourth edge roughly opposite the third edge has a catch groove. The outside door panel (2) on the third edge has a retaining rail which fits into the retaining groove and on the fourth edge has a catch rail which fits into the catch groove. The outside door panel (2) with the guide rails (12) can be pushed into the guide grooves (10) on the door frame (1) in the longitudinal direction until the retaining rail has entered the retaining groove and the catch rail has engaged the catch groove.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The invention relates to motor vehicle doors such as conventional motor 
vehicle side doors, sliding doors, rear doors which can move to the top or 
side, and rear hatches, etc. More specifically, the invention relates to 
such doors having a door frame and an outside door panel which can be 
mounted on the door frame. 
2. Description of the Related Art 
In the following specification, the term motor vehicle door is used to 
represent all the various types of doors used on motor vehicles such as 
side doors, sliding doors, rear doors and rear hatches. In motor vehicle 
doors, there is generally provided a door frame which is made as 
torsionally rigid as possible. The door frame is usually made of a metal 
or metal sections which may, in the prefered embodiment, be made from 
aluminum sections. The paneling of the door frame is accomplished by 
attaching an outside door panel to the door frame. The outside door panel 
generally made from a thin metal sheet or a molded plastic. The motor 
vehicle doors also include a corresponding inside door panel in addition 
to an inside door covering or alternatively, an integrated inside door 
panel/inside door covering. 
An important objective in designing and constructing a motor vehicle door 
is to provide a simple structure in the area of the motor vehicle door 
that will allow prompt and simple repair of any door component. Examples 
of this can be found in the published German patent applications DE 195 14 
963 A1 and DE 195 14 964 A1. 
The DE 195 14 963 A1 application discloses a motor vehicle door including a 
door frame and an outside door panel which is detachably mounted on the 
door frame. In this application, the door frame which has a retaining 
groove on an edge which runs roughly transversely to two other sides of 
the door includes a transversely running catch groove assigned to an edge 
of the outside door panel which is the upper edge when the outside door 
panel is in the installed position. The outside door panel includes a 
catch rail on a corresponding edge which is assigned to and fits into the 
catch groove. On the opposite lower edge, the outside door panel has a 
retaining groove formed by a U-shaped bend. This groove interacts with a 
retaining rail which is located on the lower edge of the inside door panel 
which is drawn forward into an area of the outside door panel. For 
mounting purposes the outside door panel is shifted from the bottom to the 
top on the door frame such that the retaining rail on the inside door 
panel fits into the retaining groove on the outside door panel and the 
catch rail on the outside door panel fits into the catch groove on the 
door frame. 
Therefore, according to this application, the motor vehicle door is 
comprised of the door frame, outside door panel, and inside door panel. 
Furthermore, the outside door panel is directly connected to the inside 
door panel, and consequently, the outside door panel can be mounted only 
in conjunction with the inside door panel. 
When using a non-reinforced plastic with high coefficient of thermal 
expansion for the outside door panel, the above explained prior art motor 
vehicle door requires considerable gap dimensions in the door area because 
the outside door panel lengthens considerably (several millimeters) in the 
longitudinal direction (in the installed position) when the outside door 
panel is heated by high ambient temperature conditions. Of course, because 
the door frame is made of a metal which has a lower coefficient of 
expansion than the plastic, the door frame does not lengthen to the same 
extent as the plastic outside door panel. 
In the motor vehicle door disclosed in German application DE 690 00 874 T2, 
the outside door panel is attached to the door frame by first pushing the 
panel vertically from the bottom to the top relative to the door frame, 
and then, by pushing the panel into the end position horizontally from the 
back to the front. When shifted horizontally, forward pointing clamps 
located on the upper edge and the front edge of the outside door panel are 
inserted into the corresponding openings on the door frame, thereby 
hooking in the outside door panel. In addition, this application also 
discloses grooves formed on the bottom edge and rear edge of the outside 
door panel which are inserted into the assigned edges of the door frame. 
Thus, the above applications disclose various feasible methods for 
attaching an outside door panel to a door frame. A disadvantage with these 
methods is that, because of the recesses in the door frame, metal-cutting 
or similar metal processing on the door frame is necessary. Furthermore, 
these prior art designs do not effectively address the problem of high 
thermal elongation of the outside door panel when these panels are heated. 
As a result, the gap dimensions required to allow this expansion remains 
large and unchanged from other designs known in the art. 
SUMMARY OF THE INVENTION 
One object of the present invention is to devise and develop a motor 
vehicle door including a door frame and an outside door panel such that 
gap dimensions between the panel and the adjacent vehicle body components 
are minimized. 
Another object of the present invention is to provide a motor vehicle door 
which can be expediently repaired and mounted. 
The aforementioned task is achieved by a motor vehicle door with the 
features of described herein. 
By using undercut guide grooves and guide rails on two opposite edges for 
attaching the outside door panel to the door frame, the outside door panel 
is fixed on the door frame at these sites. It can also be only slightly 
shifted relative to the door frame when an increase in the ambient 
temperature leads to an increase in the length of the outside door panel. 
The change in the length of the outside door panel when the temperature 
rises due to the high coefficient of thermal expansion, in this 
construction, is reflected almost exclusively in the change of the arch of 
the outside door panel. The result is that the car body can be produced 
with relatively small gap dimensions, even in the door region, because the 
gap dimensions hardly change when the ambient temperature increases. 
Tongue and groove connections selected on the transversely running edges 
round out the joining technique in the transverse direction. Here, thermal 
elongation is more acceptable. 
The construction of the invention is especially advantageous if, in it, the 
outside door panel is pushed from bottom to top onto the door frame, if 
therefore the first edge is the edge which is the front one in the 
installation position and the second edge is the edge which is the rear 
one in the installation position on the door frame and accordingly the 
third edge which runs transversely thereto is the lower edge and the 
fourth opposite edge is the upper edge on the door frame in the 
installation position. Here, it is essential that lateral, horizontal 
displacement not take place at the end of the vertical displacement 
motion. Due to the undercuts on the guide grooves and guide rails this is 
precluded. 
The older German application of the assignee of the present application 
which was not published until prior to the effective filing date of this 
application, No. DE 196 39 280 A1, discloses mounting an outside door 
panel on a door frame of a motor vehicle door solely by horizontal 
pushing. The top guide groove which runs in the pushing direction on the 
door frame is undercut in one embodiment, but the opposite guide groove is 
not. Consequently this citation does not show the bilateral fixation of 
the outside door panel on the door frame, said fixation running in the 
insertion direction and however being decisive for small gap dimensions. 
In this older application profile seals for "floating" bearing of the 
guide rails in the guide grooves are made in order to absorb the 
deformation energy for smaller side loads of the motor vehicle door. These 
construction details can also be accomplished at the corresponding 
locations in the motor vehicle door according to the present application.

DETAILED DESCRIPTION OF THE INVENTION 
The present invention is explained in detail below using a driver side door 
of a motor vehicle. However, it should be understood that the present 
invention can be easily practiced in other types of motor vehicle doors 
such as side doors, sliding doors, rear doors and rear hatches. 
The preferred embodiment of a motor vehicle door according to the invention 
is illustrated in FIG. 1, as noted, for the driver side door of the motor 
vehicle, and clearly shows the door frame 1, which in the preferred 
embodiment, is made from aluminum, and forms a hinge frame, a lock frame 
and a bottom frame. An outside door panel 2 is shown which can be attached 
to the door frame 1 as a panel and may preferably be made from a plastic 
molding. Furthermore, on the inside of the door, an inside door panel 3 is 
provided which is also a panel. In the top area of the door frame 1 there 
is a window frame 4 which is bordered underneath by a transversely running 
window shaft profile 5 of the door frame 1. These specific features and 
how window shaft profile 5 is provided inside the door frame 1 are clearly 
illustrated in FIG. 5. Both the door frame 1 and the window shaft profile 
5 act together as a module carrier, especially for attaching a window 
opener 6 (shown in its middle position), an outside door handle 
arrangement 7 and an inside door handle arrangement (not shown). The 
lowerable window pane 8 of this motor vehicle door is also clearly shown. 
FIG. 1 shows the assembly sequence of a motor vehicle door in accordance 
with an embodiment of the present invention and the final paneling of the 
door frame 1 with the outside door panel 2. 
FIGS. 2 to 5 shows various sectional views of the numerous components and 
their relative positions with respect to the door frame 1. The individual 
cross sections, however, show the door frame 1 with the outside door panel 
2 and the inside door panel 3 in their assembled positions together with 
frame sections 9 defining the door opening of the body of the motor 
vehicle into which the corresponding motor vehicle door is fitted. The 
illustrated seals are each shown in an undeformed position so that they 
are not tensioned or compressed. Thus, some overlaps occur in the drawing 
which in reality, are of course not present. 
In practicing the present invention, it is important that the door frame 1 
be provided guide grooves 10, 11 on the first edge and on the second edge 
which is opposite the first edge. These guide grooves 10 and 11 can be 
seen in FIGS. 2 and 3 and it is apparent that these two guide grooves 10, 
11 are undercut. In this embodiment, the guide grooves 10, 11 are made 
asymmetrical but having a generally T-shape. However, the undercut may 
also be L-shaped, dovetailed, or shaped in some other form. 
As illustrated in FIGS. 2 and 3, the outside door panel 2 has undercut 
guide rails 12, 13 which correspond to the guide grooves 10, 11. In this 
embodiment, the guide rails 12, 13 are made L-shaped and thus, conform 
with the undercut. It can be seen from an examination of FIGS. 2 and 3 
that, in this way, the outside door panel 2 can be shifted relative to 
door frame 1 in the lengthwise direction of the guide grooves 10, 11, but 
otherwise cannot be moved in the area of the guide grooves 10, 11. 
Furthermore, it is apparent from FIG. 4 that the door frame 1 also includes 
a retaining groove 14 on a third edge which runs roughly transversely to 
the two aforementioned first and second edges and includes a catch groove 
15 (FIG. 5) on the fourth edge which is roughly opposite the retaining 
groove. The retaining groove 14 receives a corresponding retaining rail 16 
provided on the third edge of the outside door panel 2. In a similar 
manner, the catch groove 15 receives a corresponding catch rail 17 
provided on the fourth edge of the outside door panel 2. 
For mounting purposes, the outside door panel 2 with the guide rails 12, 13 
can be pushed within the guide grooves 10, 11 on the door frame 1 in their 
longitudinal direction until the retaining rail 16 enters the retaining 
groove 14 and the catch rail 17 engages the catch groove 15. Thus, with 
the present invention, the outside door panel 2 is mounted to the door 
frame 1 with this simple movement. Dismounting of the outside door panel 
2, for example, during a repair, proceeds in exactly the reverse order of 
the installation. 
It should be made clear that the mounting sequence for mounting the outside 
door panel 2 in accordance with the present invention can take place both 
horizontally and also vertically. In the present preferred embodiment 
shown, the outside door panel 2 may be mounted through a vertical slide-on 
motion of the outside door panel 2 with respect to the door frame 1, from 
the bottom of the door to top of the door. 
Therefore, it should be clear in the embodiment shown in the drawings, that 
the first edge is the edge which is the front portion of the door in the 
installed position and the second edge is the vertically running edge of 
the door frame 1 and the outside door panel 2 which is the rear portion of 
the door in the installed position. Furthermore, it should also be clear 
that the third edge is the lower edge of the door and the fourth edge is 
the upper edge which lies in the area of the window shaft profile 5. Of 
course, the present invention may also be easily modified with edge 
designs such that the outside door panel 2 may be modified to be inserted 
by using a horizontal insertion movement. 
The upper edge and the lower edge, which extend essentially transverse to 
the direction in which the outside door panel 2 slides relative to the 
door frame 1, may be shaped differently than the front edge and the rear 
edge which generally extend in an essentially straight line. More 
specifically, the upper edge and the lower edge can extend in an arc or a 
curve, as clearly illustrated in the rear edge of the outside door panel 2 
in FIG. 1 which is provided as a wheel guard cutout. 
It should be apparent that the present invention may be practiced such that 
the pairs of grooves and rails which are disclosed above can be 
interchanged in their assignment with respect to the door frame 1 and the 
outside door panel 2. In other words, the present invention may also be 
practiced by providing an outside door panel 2 with grooves instead of 
rails and providing a door frame 1 with rails instead of grooves. The 
features of the present invention can also be combined such that both the 
door frame 1 and the outside door panel 2 each include grooves and rails, 
each on a corresponding edge or any combination thereof, such that 
installtion of the type disclosed above is possible. And as discussed 
previously, it should also be evident in practicing the present invention 
that the retaining groove/retaining rail pair or the catch groove/catch 
rail pair can also be interchanged in their assignment to the bottom edge 
and the top edge or to the front edge and the rear edge when the outside 
door panel 2 is inserted horizontally. 
FIGS. 6 and 7 clearly show a motor vehicle door in accordance with an 
embodiment of the present invention. As shown, there may be gaps 18 
between the door and the door opening on the vehicle frame. By fixing the 
edges opposite one another by guide grooves 10, 11 and guide rails 12, 13, 
the outside door panel 2, which generally is made of plastic, does not 
yield laterally when the ambient temperature rises and the outside door 
panel 2 expands. FIG. 7 illustrates what actually occurs when the 
temperature rises. As indicated by the plurality of arrows, the convexity 
of the outside door panel 2 changes as a result of the expansion. Because 
the expansion results in slight bending of the outside door panel 2, the 
width of the gaps 18 decreases by a small amount. However, the dimensional 
changes in the gaps 18 are minimal and are in the range of less than 1 mm, 
which is substantially less than gap reductions experienced in the prior 
art designs. 
This constancy of the gap dimensions is especially important on the 
essentially vertically extending edges of the motor vehicle door in the 
door cutout 9. In the area of the lower edge of the motor vehicle door, 
there need not be any gaps at all since the motor vehicle door can overlap 
the car body at this location. In addition, there need not be any gaps in 
the upper area of the outside door panel 2 at the ends of the window shaft 
profile 5 either since it would be visually important to have no gaps in 
this area. Accordingly, the vertical extension of the outside door panel 2 
becomes especially important within the framework of the present 
invention. 
Furthermore, although the embodiment discussed above includes continuous 
grooves and rails, the present invention may also be modified so that 
grooves and rails are provided only on partial sections of the available 
length if the door design so allows. This embodiment can be recommended 
especially for the molded plastic outside door panel 2. In the extruded 
profiles which generally comprise the door frame 1, this alternative 
embodiment of the present invention is less significant. 
Absolute accuracy in the alignment of the guide grooves 10, 11 is not 
required. The embodiment of the present invention shown in the plane of 
the motor vehicle door exhibits guide grooves 10, 11 which are each 
"radially" open to the outside on the door frame 1 with the openings. This 
has an advantage in that the outside door panel 2 can be removed only when 
the motor vehicle door is opened thereby providing protection against 
theft. More specifically, this advantage is attained because the first, 
second and third edges, which preferably correspond to the front, rear and 
lower edges of the outside door panel 2, are bent in a substantially 
L-shape, or more preferably, are bent in a substantially U-shape thereby 
forming the guide rails 12, 13 and the retaining rails 16. Therefore, the 
formed bends and the corresponding guide grooves 10, 11 and retaining 
groove 14 are aligned to fit accordingly. 
The change in the length of the inside door panel 3 when the temperatures 
changes, as exemplified by the arch shown in FIG. 7, can be reduced by the 
outside door panel 2 being made as a plastic molding of glass fiber 
reinforced plastic. With glass fiber reinforced plastic, the coefficient 
of thermal expansion differs relative to the direction of the fiber 
reinforcement and the fibers can be oriented to correspond to the 
installation position of the outside door panel 2. 
By sliding on the outside door panel 2, it can be easily prestressed at low 
temperatures because the guide grooves 10, 11 and the guide rails 12, 13 
are undercut and enable generation of a corresponding stress. This yields 
an especially torsionally-stiff construction of the motor vehicle door 
which minimizes noise development, increases the precision of fit of the 
door and relatedly, provides good sealing performance, thereby minimizing 
wind noise. 
In addition, any metal cutting on the door frame 1 can be minimized in a 
motor vehicle door in accordance with the present invention. Furthermore, 
because the outside door panel 2 can be easily replaced, the 
serviceability of a motor vehicle door in accordance with the present 
invention is comparable to serviceability of other motor vehicle doors 
which are known from unpublished prior art. 
It must be also noted that, in the present embodiment, the outside door 
panel 2 includes a slip-on recess 19 on the upper edge for receiving a 
window shaft seal 20 as clearly illustrated in FIG. 5. 
Furthermore, profile seals 21 are provided between the individual grooves 
and the rails which fit into the grooves. This is especially apparent in 
the retaining groove 14 on the lower edge of the door frame 1 as 
illustrated in FIG. 4. FIG. 4 also illustrates another embodiment where 
the profile seals 21 are integrally made of one-piece with the door-car 
body seal 22. These door/car body seals 22 are also illustrated in the 
various figures at positions where they are conventionally applied. The 
illustrated "floating" support of the outside door panel 2 provided by the 
profile seal 21 in the retaining groove 14 is also known from the above 
mentioned commonly-owned, unpublished prior application. 
FIGS. 1 and 5, viewed in conjunction with FIG. 8 provides a better 
indication of how the inside door panel 3, which serves as an inside panel 
covering, is attached to the door frame 1. This corresponds to a system 
which, in this or a similar manner, is essentially considered the prior 
art. The inside door panel 3 is suspended at its upper edge in a 
suspension groove 23 provided on the door frame 1 and which opens towards 
the top of the door frame 1. The inside door panel's lower edge is hooked 
on the door frame 1 by means of catch hooks 24 as illustrated in FIG. 8. 
The peripheral edge 25 of the inside door panel 3 corresponds to an inside 
peripheral edge of the door frame 1 while the peripheral flange 26 
resiliently adjoins the door frame 1. 
For the sake of completeness, it is noted that the cross section 
illustrated in FIG. 2 also includes a hinged joint 27 which is screwed 
onto the door frame 1 and establishes the connection of the motor vehicle 
door to the motor vehicle body on the door cutout 9.