VEHICLE FRONT PANEL ARRANGEMENT
TECHNICAL FIELD
The invention relates to a lower front panel according to the preamble of claim 1. The invention also relates to a cab-over engine commercial vehicle according to the preamble of claim 6.
BACKGROUND ART
Cab-over engine type vehicles, in particular trucks, are designed with the engine located below the cab. One advantage with this configuration is that by minimizing the space taken up by the cab and power plant it is possible to use a longer body or cargo space of a truck with the same over-all length. In the case of a tractor and trailer combination, it is possible to use longer trailer units within a predetermined or maximum allowed over-all length.
In cab-over engine type trucks the cab is normally tilted forward over the engine for service access to the engine. For driver comfort, a suspension system is arranged between the cab and the truck chassis to reduce chassis to cab vibration transfer. Typically, the cab suspension system can be designed to allow a vertical cab movement of +/- 50 mm. A typical cab suspension system also allows some cab motion around the pitch-, roll- and yaw-axle.
On a cab-over engine truck, the front panels, i.e. the panels attached to the front of the chassis frame and the front of the cab, are normally arranged so that there is a substantial clearance between chassis panels and cab panels for cab movement, both for normal suspension motion and for tilting the cab from a normal position of use to an engine access position. This clearance at the front of the truck can have a negative influence on the aerodynamic efficiency of the vehicle, and may also be considered as negative to the aesthetical appearance of the vehicle.
When designing a truck, consideration for maximizing both loading capacity and driver comfort within a given vehicle length is normally taken. Thus, it is difficult to provide enough space for positioning panels at the front of a truck with enough clearance for the above described movements.
The invention aims to provide an improved lower front panel for a cab-over engine truck that overcomes the above problems relating to the clearance between lower front panels of the chassis and the cab structure, while maintaining the functional motion properties.
DISCLOSURE OF INVENTION
The invention solves the above problems by means of an improved lower front panel according to the characterizing part of claim 1 , wherein the lower front panel is provided with a panel segment which is adapted to follow the tilt angle of the cab when the cab is tilted from a normal position of use to a service access position. The improved lower front panel makes it possible to position the panel close to the front suspension components of the cab without interfering with cab movements.
According to a preferred embodiment of the invention, the panel segment is connected to the lower front panel via a hinge allowing the segment to swing to an open position when the cab is tilted to the service access position.
Preferably, the hinge is provided with a spring means acting to return the panel segment from the open position to a closed position.
According to another embodiment of the invention, the hinge is connected to the panel segment via a goose-neck portion.
The panel segment is preferably adapted to permit parts of the cab suspension system to pass the upper edge of the lower front panel when the cab is tilted to the service access position.
In a cab-over engine commercial vehicle according to the invention, the cab suspension system is preferably provided with an actuator for moving a segment of the lower front panel from a closed position when the cab is tilted to the service access position. The actuator may be adjustably connected to the cab suspension system.
BRIEF DESCRIPTION OF DRAWINGS
In the following text, the invention will be described in detail with reference to the attached drawings. These schematic drawings are used for illustration only and do not in any way limit the scope of the invention. In the drawings:
Figure 1 shows a perspective view of the front panels of a cab-over engine truck with a lower front panel in accordance with the invention;
Figure 2 shows a broken side section view of the front end of a truck in accordance with Figure 1 ;
Figure 3 shows a perspective view of the lower front panels with parts of the cab suspension and tilting system; and
Figure 4 shows a perspective view of the lower front panels from the opposite direction as in Figure 3.
EMBODIMENTS OF THE INVENTION
Figure 1 shows a perspective view of the front panels of a cab-over engine truck provided with a chassis frame 10 and a driver cab 11. The truck frame 10 has two substantially parallel longitudinal beams. An engine (not shown) is mounted between the beams of the frame 10 underneath at least the rear section of the cab 11 and extends through an engine tunnel passing through the centre of the cab between a pair of individual seats (not shown). The front panels comprise lower front panels 12 and upper front panels 13. The lower front panels 12 are attached to the chassis frame 10 and the upper front
panels 13 are attached to the cab 11. The panels 12, 13 are installed with a mutual vertical overlap, so as to avoid a vertical gap between lower and upper panels.
As shown in figure 2, the cab 11 is supported at the front end of the frame 10 by means of a shock absorber unit 14 positioned at each side of the truck engine coolers (not shown in the drawings). Each shock absorber unit 14 is connected at its upper end to the cab (not shown in the drawings) and connected at its lower end to the chassis frame 10 via a link arm 15. The link arm is mounted between an attachment point 16 on the cab and an attachment point 17 at the front end of the frame 10 for controlling vertical movement of the cab 11 in relation to the frame. Thus, the cab is suspended in relation to the frame for driver comfort. The link arm 15 is provided with an actuator finger 18, which is adjustably connected to the link arm.
A torsion bar 19 is rigidly connected to the two link arms 15 and rotatably supported by the attachment points 17 at the front end of the frame. The torsion bar 19 acts like a stabilizer for the cab 11 when turning the truck, for minimizing cab sideways roll when driving through turns, by transferring force from the loaded side of the cab suspension to the unloaded side. The rotatably supported torsion bar 19 also functions as pivot point for the cab 11 when tilting the cab from a normal position of use to an engine service access position, for example with an angle of forward tilt of about 60 degrees.
According to Fig. 1 and 2, the front panels 12, 13 are designed and attached to the vehicle frame so that the upper edge 12a of the lower front panels 12 overlaps the lower edge 13a of the upper front panels 13. To enable tilting of the cab 11 to its service access position without having the cab suspension interfering with the lower front panels, the mid section of the lower front panel 12 is provided with two side panel segments 20. Each of these two panel segments 20 is located in front of the respective left and right panel suspension. Each panel segment 20 is adapted to follow the tilt angle of the cab 11 when the cab is tilted from a normal position of use to the service
access position. This is made possible by connecting each of the panel segments 20 to the main lower front panel 12 via a hinge 21 allowing the segments to swing to an open position when the cab 11 is tilted to the service access position.
The hinge 21 is connected to the panel segment 20 via a goose-neck portion 22 which allows the panel segment 20 to pivot around a pivot point 21a located at the back of the mid section of the lower front panel. This arrangement makes it possible to get a tight fit with overlap between the panel segment 20 and the mid section of the lower front panel. This tight fit and overlap is important for aerodynamic control of airflow around the vehicle front.
When the cab 11 is tilted to the service access position the cab 11 pivots forward with the link arm 15, shock absorber 14 and the torsion bar 19 in the attachment points 17. During this cab movement the outer end of the actuator finger 18 contacts the inside of the panel segment 20 to open a clearance for the shock absorber 14, at each side of the mid section of the lower front panels. Now the two panel segments 20 can slide between the inside of the upper front panel 13 and the shock absorbers 14 during the tilting movement.
The hinge 21 is provided with a torsion spring 23 (see Fig. 4) acting to return the panel segment 20 from the open position to the closed position when the cab is returned from its service access position to its normal position of use.
Thus, the arrangement of the panel segments 20 in accordance with the invention facilitates an aerodynamically efficient design of a cab-over engine truck with normal cab suspension functionality and forward tilt functionality.
The invention is not limited to the embodiments described above, but may be varied freely within the scope of the claims. For example, the two panel segments 20 in the above described embodiment could be replaced by a single wide panel segment.