GB2527947A - Bumper assembly for a commercial vehicle - Google Patents

Abstract

The invention relates to improving the aerodynamics of a commercial vehicle front bumper assembly 10 with a first upper bumper 12 and second flush lower bumper 14 that can be vertically lowered and raised through an actuator with a four-bar linkage 18, and from the used position be raised by actuation of the braking system.

Description

Bumper Assembly for a Commercial Vehicle The invention relates to a bumper assembly for a commercial vehicle according to the preamble of patent claim 1.

Such a bumper assembly for a commercial vehicle can be found in GB 2512477 A. The bumper assembly comprises at least one first front bumper panel configured to be arranged at a front end of the commercial vehicle. Furthermore, the bumper assembly comprises at least one second front bumper panel which is movable in relation to the first front bumper panel between a retracted position and at least one use position. In the retracted position at least a portion of the second front bumper panel is covered by the first front bumper panel in the longitudinal direction of the vehicle. Moreover, in the use position, said portion is uncovered and arranged below the first front bumper panel with respect to the vertical direction of the vehicle.

It is an object of the present invention to provide a bumper assembly of the aforementioned kind, by means of which particularly advantageous aerodynamics as well as a particularly advantageous usability of the commercial vehicle can be realized.

This object is solved by a bumper assembly having the features of patent claim 1.

Advantageous embodiments with expedient developments of the invention are indicated in the other patent claims.

In order to provide a bumper assembly of the kind indicated in the preamble of patent claim 1, by means of which bumper assembly particularly advantageous aerodynamics as well as a particularly advantageous usability of the commercial vehicle can be realized, according to the present invention, the bumper assembly comprises at least one four-bar linkage by means of which the second front bumper panel is movable, in particular pivotable, and arranged on the first bumper panel. Thereby, a particularly advantageous movement of the second front bumper panel can be realized so that, for example, respective front sides of the front bumper panels sit at least substantially flush in the use position. Thus, particularly advantageous aerodynamics of the commercial vehicle can be realized. The use position is a lowered position of the second front buniper panel acting as an air dam which, in the use position, provides or covers a frontal area underneath the first front bumper panel. The retracted position is a raised position in which the second front bumper panel is arranged higher than in the use position with respect to the vertical direction of the vehicle.

In the use position, the second front bumper panel acts as an air dam which reduces the drag of the commercial vehicle, in particular at highway speeds, in comparison with the second front bumper panel being in the retracted position. As a result of the drag reduction a fuel economy improvement can be realized. In other words, by lowering the second front bumper panel from the retracted position to the use position the fuel economy of the commercial vehicle at highway speeds can be improved since air is directed away from underbody components by the second front bumper panel being lowered and, thus, in the use position.

However, if, for example, the commercial vehicle needs to be driven up a ramp, the second front bumper panel can be raised and, thus, moved from the use position to the retracted position so that a collision between the second front bumper panel and the ramp can be avoided. This means the second front bumper panel can be moved between the use position and the retracted position in a need-based manner so that both a particularly advantageous usability and particularly advantageous aerodynamics of the commercial vehicle can be realized. By raising the second front bumper panel from the use position to the retracted position, damages of the second front bumper panel can be avoided.

Utilizing a moving air dam in the form of the second front bumper panel can help avoid road and parking damages to the second front bumper panel due to added ground clearance in the retracted position. Hence, long-term maintenance costs will be less compared to stationary air dams as a result of less frequent system damage.

By using at least one four-bar linkage to realize the movement of the second front bumper panel between said positions a particularly advantageous movement of the second front bumper panel can be realized in a space-effective way. For example, in the retracted position, at least said portion of the second front bumper panel can be arranged behind the first front bumper panel with respect to the longitudinal direction of the vehicle.

However, in the use position, said portion can be arranged below the first front bumper panel and sit flush with the first front bumper panel. Getting the second front bumper panel (air dam) at least substantially flush to the first front bumper panel maximizes the drag reduction effects of the bumper assembly. Especially, an excessive step back from the first bumper panel to the second front bumper panel can be avoided thereby realizing particularly advantageous aerodynamics of the commercial vehicle.

The invention also relates to a method for operating a bumper assembly according to the present invention. In said method the second front bumper panel is moved, by means of at least one actuator, between the positions on the basis of the speed of the commercial vehicle.

In order to avoid damages of the second front bumper assembly, in an advantageous embodiment of the invention, the second front bumper panel is moved from the use position to the retracted position on the basis of an actuation of a brake system of the commercial vehicle. Preferably, the second front bumper panel is moved from the use position to the retracted position when the brake system is actuated.

Further advantages, features, and details of the invention result from the following description of a preferred embodiment as well as from the drawings. The features and feature combinations previously mentioned in the description as well as the features and feature combinations mentioned in the following description of the figures and/or shown in the figures alone can be employed not only in the respectively indicated combination but also in other combination or taken alone without leaving the scope of the invention.

The drawings show in: Fig. 1 a schematic perspective view of a bumper assembly for a commercial vehicle, the bumper assembly comprising a first front bumper panel and a second front bumper panel which is in its retracted position; Fig. 2 a schematic perspective view of the bumper assembly with the second front bumper panel being in an intermediate position; Fig. 3 a schematic and perspective front view of the bumper assembly with the second front bumper panel being in its use position; Fig. 4 a further schematic and perspective front view of the bumper assembly with the second front bumper panel being in its retracted position; Fig. 5 a schematic side view of the bumper assembly with the second front bumper panel being in its retracted position; Fig. 6 a schematic side view of the bumper assembly with the second front bumper panel being in an intermediate position; and Fig. 7 a schematic side view of the bumper assembly with the second bumper panel being in its use position.

In the figures the same elements or elements having the same functions are indicated by the same reference signs.

Fig. 1 shows a bumper assembly 10 in the form of a front bumper assembly for a commercial vehicle, in particular, a truck. As can be seen from Figs. 1-4 the bumper assembly 10 comprises a first front bumper panel 12 which is made of, for example, a plastic material. Moreover, the first front bumper panel 12 can be inherently stable. Figs. 1 and 2 show a view of the left hand side of the front bumper assembly from the center of the commercial vehicle, looking out. The right hand side of the front bumper assembly is a mirror of the left hand side. The first front bumper panel 12 is configured to be arranged at a front end of the commercial vehicle. For example, the first front bumper panel 12 is used to cover a cross member of the truck in the longitudinal direction of the vehicle towards the front.

The bumper assembly 10 further comprises a second front bumper panel 14 which can be formed in one piece. In other words, the second front bumper panel 14 is, for example, a single piece. For example, the second front bumper panel 14 can be made of a plastic material. Moreover, the second front bumper panel 14 can be inherently stable. Moreover, the second front bumper panel 14 can be elastic. As can be seen from Figs. 1 and 2, the second front bumper panel 14 is movable, in particular pivotable, in relation to the first front bumper panel 12 between a retracted position shown in Fig. 1 and at least one use position shown in Fig. 2. The retracted position is also referred to as a raised position, wherein the use position is also referred to as a lowered position. In the retracted position at least a portion 16 of the second front bumper panel 14 is covered by the first front bumper panel 12 in the longitudinal direction of the vehicle towards the front since, in the retracted position, at least said portion 16 is arranged behind the first front bumper panel 12 with respect to the longitudinal direction of the vehicle. In the use position the portion 16 is uncovered and arranged below the first front bumper panel 12 with respect to the vertical direction of the vehicle. In other words, in the retracted position, the portion 16 is covered by the first front bumper panel 12 in the longitudinal direction of the vehicle towards the front. In the use position the second front bumper panel 14 is lowered with respect to the retracted position so that the portion 16 is not covered by the first front bumper panel 12.

In order to realize particularly advantageous aerodynamics of the commercial vehicle as well as a particularly advantageous usability of the bumper assembly 10, the bumper assembly 10 comprises at least two four-bar linkages. A first one of said four-bar linkages is arranged on the right hand side and cannot be seen in the figures. The second four-bar linkage is arranged on the left hand side and indicated by 18. The previous and following statements with respect to the four-bar linkage 16 also apply for the four-bar linkage arranged on the right hand side and vice versa.

As can be seen from Figs. 1 and 2 the four-bar linkage 18 comprises a first linkage arm 20 which is also referred to as a front linkage arm. Moreover, the four-bar linkage 18 comprises a second linkage arm 22 which can be seen in Fig. 2, wherein the second linkage arm 22 is also referred to as a rear linkage arm. The linkage arms 20 and 22 are bars of the four-bar linkage 18. The bumper assembly 10 further comprises a mounting structure 24 which is arranged on the first front bumper panel 12. For example, said mounting structure 24 is made of sheet metal. The linkage arms 20 and 22 are pivotably arranged on the mounting structure 24 so that, for example, the mounting structure 24 is a third bar of the four-bar linkage 18. To complete the four-bar linkage 18 the second front bumper panel 14 is pivotably connected to the linkage arms 20 and 22 so that the second front bumper panel 14 acts as the fourth bar of the four-bar linkage 18. In other words, the linkage arms 20 and 22 are moving or pivoting linkage arms via which the second front bumper panel 14 is pivotably arranged on the mounting structure 24 and, thus, the first front bumper panel 12.

Since the linkage arm 20 is pivotably connected to both the mounting structure 24 and the second front bumper panel 14 the linkage arm 20 is pivotable in relation to the mounting structure 24 about a first pivot axis and pivotable in relation to the second front bumper panel 14 about a second pivot axis. Moreover, since the linkage arm 22 is pivotably connected to both the mounting structure 24 and the second front bumper panel 14 the second linkage arm 22 is pivotable in relation to the mounting structure 24 about a third pivot axis and pivotable in relation to the second front bumper panel 14 about a fourth pivot axis. For example, the linkage arms 20 and 22 rotate about their respective centers to form the four-bar linkage 18 which is also referred to as a tour-bar linkage system. The linkage arm 22 is smaller than the linkage arm 20 and moved due to movements of a sheet metal linkage component. As that force is transmitted, the linkage arm 22 rotates about its axes to lower or raise the rear of the second front bumper panel 14 which is also referred to as an air dam.

By means of the four-bar linkage 18 a particularly advantageous movement of the second front bumper panel 14 can be realized. Said advantageous movement of the second front bumper panel 14 provides superior placement of the air dam (second front bumper panel 14) in relation to thefirstfront bumper panel 12. By using the four-bar linkages on the left hand side and the right hand side the second front bumper panel 14, when moving from the retracted position to the use position, moves downwards in the vertical direction of the vehicle and forwards in the longitudinal direction of the vehicle. Thus, in the use position, a first front side 26 (Figs. 3 and 4) sits at least substantially flush with a second front side 28 of the second front bumper panel's 14 portion 16, wherein said front sides 26 and 28 face towards the front in the longitudinal direction of the vehicle. Getting the air dam at least substantially flush to the first front bumper panel 12 maximizes the drag reduction effects of the bumper assembly 10. By using the four-bar linkages an excessive step back of the second front bumper panel 14 in relation to the first front bumper panel 12 can be avoided. Thus, particularly advantageous aerodynamics of the commercial vehicle can be realized.

As can be seen from Figs. 3 and 4, in the retracted position, the second front side 28 is arranged behind the first front side 26 in the longitudinal direction of the vehicle. Thus, at least the portion isis covered by means of the first front bumper panel 12 in the longitudinal direction of the vehicle towards the front.

The bumper assembly 10 comprises two actuators configured as pneumatic actuators, in particular linear pneumatic actuators. One of said pneumatic actuators is arranged on the right hand side, wherein the second pneumatic actuator is arranged on the left hand side.

Thus, the second pneumatic actuator can be seen in Figs. 1 and 2, wherein second the pneumatic actuator is indicated by 30. At least a portion of the pneumatic actuator 30 is arranged in the mounting structure 24, wherein the pneumatic actuator 30 comprises a cylinder 32 and a piston which cannot be seen in Figs. 1 and 2. Said piston is translationally movably arranged in the cylinder 32 and connected to a piston rod 34 of the pneumatic actuator 30. The cylinder 32 and said piston bound a working chamber which can be supplied with air. By feeding air into said working chamber the piston is moved in relation to the cylinder 32 thereby moving the piston rod 34 out of the cylinder 32. Thereby, the second front bumper panel 14 is moved from the retracted position to the use position since the cylinder 32 is pivotably connected to the mounting structure 24 and the piston rod 34 is pivotably connected to the linkage arm 20.

By discharging the air out of the working chamber the piston rod 34 is moved into the cylinder 32 thereby moving the second front bumper panel 14 from the use position to the retracted position. This means the respective linear pneumatic actuator provides the movement for the respective four-bar linkage. For example, the commercial vehicle comprises at least one electronic control unit not shown in the figures, wherein the electronic control unit is electronically connected to the respective pneumatic actuators.

Thus, the actuators can be controlled by the electronic control unit on the basis of, for example, a control logic. Thus, by means of the electronic control unit, a method for operating the bumper assembly 10 can be realized. Preferably, in said method, the second front bumper panel 14 is moved, by means of the pneumatic actuators, between the retracted position and the use position on the basis of the speed of the commercial vehicle. For example, the movable air dam (second front bumper panel 14) is deployed to the use position at speeds above 40 miles per hour (mph), i.e. at highway speeds. As the commercial vehicle slows down below 25 mph the control logic and, thus, the electronic control unit signals the pneumatic actuators to retract the air dam to the safe retracted position which is a stowed position.

Preferably, said control logic comprises a strategy to retract the air dam, i.e. to move the second front bumper panel 14 from the use position to the retracted position on the basis of an actuation of a brake system of the commercial vehicle. In other words, when the brake system is actuated by, for example, driver of the commercial vehicle on-highway, the second front bumper panel 14 is moved from the used position to the retracted position. This feature is for the use case of avoiding objects and animals on the road when actuating the brake system and, thus, braking the commercial vehicle.

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By moving the air dam from the retracted position to the use position the air dam is lowered in the vertical direction of the vehicle and moved forwards in the longitudinal direction of the vehicle. Thus, in the use position, the air dam is closer to the ground than in the retracted position thereby providing a reduction in the aerodynamic drag. Since the pneumatic actuator 30 is hinged between the linkage arm 20 and the stationary sheet metal in the form of the mounting structure 24 the pneumatic actuator 30 pivots slightly around pivot axes to transmit force to the linkage arm 20.

Fig. 5 shows the retracted position of the air dam. At slow speeds, the actuator 30 retracts to pivot the two linkage arms 20 and 22. The linkage arms 20 and 22 rotate back and up to place the air dam in a safe location to prevent damage from curbs, road debris etc. Fig. 6 shows an intermediate position of the air dam, said intermediate position being also referred to as a mid-deployment. When the vehicle speed is greater than a threshold set by the control logic or a control algorithm, the actuator 30 is powered to provide the force to rotate the linkage arm 20. The linkage arm 20 rotates about its pivot axes so that the motion of the actuator 30 is transferred through the linkage arm 22 and the second front bumper panel 14 to cause the linkage arm 22 (rear linkage) to move about its pivot axes. The intermediate position or mid-deployment is temporary and only experienced when moving the second front bumper panel 14 between the retracted and use positions.

Fig. 7 shows the bumper assembly 10 with the second front bumper panel 14 being in the use position. In the use position the air dam is fully deployed. This is the desired state of the bumper assembly 10 when the vehicle is travelling at highway speeds. Then, the pneumatic actuator 30 is fully extended and charged with air to provide the force to keep the air dam lowered, i.e. in the use position. As the air dam pivots on the two linkage arms and 22, its motion traverses towards the front of the vehicle.

List of reference signs bumper assembly 12 first front bumper panel 14 second front bumper panel 16 portion 18 four-bar linkage linkage arm 22 linkage arm 24 mounting structure 26 front side 28 front side pneumatic actuator 32 cylinder 34 piston rod