GB2564705A

GB2564705A - Mounting device for mounting a hood on a chassis of a commercial vehicle

Info

Publication number: GB2564705A
Application number: GB1711746.6A
Authority: GB
Inventors: Raleigh Darren; Crow Franklin; Dawson Michael; Foo Derrick; Jensen David; Koch John; Visan Nathan
Original assignee: Daimler AG
Current assignee: Mercedes Benz Group AG
Priority date: 2017-07-21
Filing date: 2017-07-21
Publication date: 2019-01-23
Also published as: GB201711746D0

Abstract

A mount 16 for mounting the hood or bonnet (12, fig. 1) of a commercial vehicle, e.g. a truck. The mount 16 includes a first mounting bracket (20, fig. 1) to be attached to the vehicle chassis (14, fig. 1) and a second mounting bracket 22 attached to the first. A lever arm 24 is pivotably arranged on the second bracket, and pivotably connected to the hood (via part 44). An elastically deformable device 26 (e.g. with springs 54) is supported on the arm and the second bracket, and deformed by moving the arm 24 relative to the second bracket. The pivotal connection 28 between the second bracket and the arm may be a bolt 30 held on the bracket and surrounded by a sleeve 32 connected to the arm and may also include polymer bushings 34. The elastically deformable device may be supported at both ends on the second bracket and between the ends on the lever arm (best seen in figures 3 and 4). The lever arm may have an unequal rocker arm ratio. The mount is used to reduce the stress load transmitted to the hood by isolating it from engine vibrations.

Description

Mounting Device for Mounting a Hood on a Chassis of a Commercial Vehicle

The invention relates to a mounting device for mounting a hood on a chassis of a commercial vehicle, in particular a truck.

GB 2522132 A shows a hinge for mounting a hood on a structure of a commercial vehicle, the hinge comprising at least one mounting bracket configured to be attached to the structure. The hinge further comprises at least one lever pivotably arranged on the mounting bracket, and at least one pivot pivotably arranged on the lever arm, and configured to be attached to the hood. Furthermore, the hinge comprises an elastically deformable device supported on the lever arm and the mounting bracket, and configured to be elastically deformed by moving the lever arm in relation to the mounting bracket.

It is the object of the present invention to provide a mounting device by means of which a hood can be mounted on a chassis of a commercial vehicle particularly precisely.

This object is solved by a mounting device having the features of patent claim 1. Advantages embodiments with expedient developments of the invention are indicated in the other patent claims.

According to the present invention, the mounting device for mounting a hood on a chassis of a commercial vehicle comprises at least one first mounting bracket configured to be attached to the chassis, in particular a rail of the chassis which is also referred to as a frame. Moreover, the mounting device according to the present invention comprises at least one second mounting bracket attached to the first mounting bracket. Moreover, the mounting device according to the present invention comprises at least one lever arm and an elastically deformable device. Said lever arm is pivotably arranged on the second mounting bracket, and configured to be pivotably connected with the hood. The elastically deformable device is supported on the lever arm and the second mounting bracket respectively, wherein the elastically deformable device is configured to be elastically deformed by moving, in particular pivoting the lever arm in relation to the second mounting bracket.

For example, the second mounting bracket is bolted to the first mounting bracket being an additional mounting bracket which is fixed or can be fixed to the chassis so that the second mounting bracket can be attached to this chassis via the first mounting bracket. Thus, the use of the first mounting bracket allows the mounting device to be adjusted relative to the chassis in a need-based manner. It has been found that said adjustment of the mounting device can be necessary in a production environment to account, for example, build variations and tolerance stack up. Since, by using the first and second mounting brackets, the mounting device can be adjusted relative to the chassis, the hood can be adjusted relative to the chassis and/or relative to components which are mounted on the chassis at least indirectly so that respective gaps between the hood and said components, in particular external panelling elements of the commercial vehicle can be adjusted precisely and in a need-based manner.

For example, the mounting device according to the present invention is a hood front mount used to reduce stress loads that are transmitted into the hood from the chassis during operation of the commercial vehicle which is, for example, a truck, by isolating the hood from chassis inputs. For example, the lever arm is used as a rocker arm having an unequal rocker arm ratio. In this regard, for example, the mounting device has a first distance between a first point and a second point, wherein, at the first point, the lever arm is supported on the elastically deformable device and wherein, for example, the second point is arranged on a pivot axis about which the lever arm can rotate in relation to the second mounting bracket. Moreover, for example, the mounting device has a second distance between the second point and a third point, wherein, for example, the third point is arranged on a second pivot axis about which the lever arm can rotate in relation to the hood, in particular when opening and/or closing the hood. In this regard, for example, the distances are unequal, wherein, for example, the first distance is shorter than the second distance or vice versa. Thus, the lever arm has an unequal rocker arm ratio. Moreover, for example, the elastically deformable device comprises at least two spring elements which are configured as, for example, coil springs. Preferably, said spring elements are arranged in parallel. The use of said unequal rocker arm ratio and said spring elements allows for realising such a design of mounting device so as to target a desired frequency response for proper isolation of the hood from the chassis. The invention also lends itself to being adapted across multiple applications through variations of said spring elements. This reduces the development time needed for hood mounts and design proliferation. The idea behind the invention is that the purpose of a hood front mount is to support the front of the hood and to allow the hood to pivot open for inspection and maintenance of the engine compartment and to pivot close to protect the under hood components during truck operations from natural elements, road debris and other damaging factors. The advantage of the design of the mounting device according to the present invention is improved hood durability for off highway applications resulting in reduced wear and downtime for its owner. Another advantage of the mounting device according to the present invention is that the mounting device according to the present invention can be easily tuneable to multiple hoods with a simple spring change to alter the stiffness of the mounting device to achieve a desired frequency. This allows a manufacturer to have a single high volume base design made of the more costly mounting components reducing part proliferation, cost, and design complexity.

For example, said spring elements are metallic springs such as coil springs or nonmetallic springs such as polymer compression spring elements. For example, the lever arm is pivotably arranged on the second mounting bracket by means of at least one bolted joint connection comprising a bolt held on the second mounting bracket. Moreover, the bolted joint connection comprises a sleeve concentrically arranged on the bolt, said sleeve surrounding the bolt in its circumferential direction, wherein the lever arm is pivotably arranged on the sleeve. Moreover, the bolted joint connection comprises at least one polymer bushing by means of which the lever arm is pivotably supported on the sleeve and/or the second mounting bracket.

For example, a bushing of sufficient strength and wear characteristics could be used to function as both said polymer bushing and said sleeve, which, for example, acts as a compression limiter sleeve. In this regard, for example, the lever arm is allowed to articulate or pivot on said compression limiter sleeve which is concentric with or on said bolt being a lever arm pivot bolt. By using said bolted joint connection the complexity of the mounting device can be kept particularly low.

Furthermore, by means of the invention it is possible to eliminate the use of a bolt, washer and a nut to retain said spring element. Instead, for example, the elastically deformable device is or the spring elements are, with respect to the axial direction of the elastically deformable device, supported at both ends on the second mounting bracket at least indirectly, wherein the lever arm is, in the axial direction of the elastically deformable device, supported on the elastically deformable device at least indirectly between said ends of the elastically deformable device. Thus, for example, the spring elements are retained via the lever arm and the second mounting bracket being, for example, an arm mount geometry which retains, for example, bump stops used to locate said spring elements within the mounting device. For example, said bump stops also serve to control the lever arm travel under extreme events and to eliminate metal on metal contact to improve the quality and durability of the design. Moreover, the polymer bushing can function as a lubricious polymer bushing to reduce pivot wear to also serve as a quality improvement.

Further advantages, features, and details of the invention derive 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 any other combination or taken alone without leaving the scope of the invention.

The drawings show in:

Fig. 1 part of a schematic perspective view of an arrangement of a hood on a chassis of a commercial vehicle, in which arrangement the hood is pivotably mounted on the chassis by mounting devices according to the present invention;

Fig. 2 a schematic exploded view of one of said mounting devices;

Fig. 3 a schematic perspective view of the mounting device according to Fig. 2;

Fig. 4 a schematic perspective view of an arrangement of said mounting device on said chassis;

Fig. 5 part of a schematic side view of the commercial vehicle; and

Fig. 6 a schematic sectional view of said mounting device.

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

Fig. 1 shows in a schematic perspective view an arrangement 10 of a hood 12 on a chassis 14 of a commercial vehicle such as, for example, a truck. In the arrangement 10 the hood 12 is pivotably arranged on the chassis 14 by means of at least two mounting devices, wherein one of said mounting devices can be seen in Fig. 1 and is indicated by

16. The hood 12 is a front hood which is configured to cover an engine compartment. Since the hood 12 is pivotably arranged on the chassis 14 of which a rail 18 can be seen in Fig. 1, the hood 12 can be pivoted between at least one closed position and at least one open positon in relation to the chassis 14. For example, the rail 18 is lateral longitudinal member of the chassis 14 which is also referred to as a frame. The closed hood 12 also functions as a styled aerodynamic surface reducing the overall drag of the commercial vehicle thereby increasing fuel efficiency. In terms of the design aspect of supporting the front of the hood 12 on the chassis 14, the mounting device 16 which is also referred to as a mount, front mount or hood front mount can be designed in such a way that stresses transmitted to the hood 12 from the chassis 14 are reduced, thus improving the life expectancy of the hood 12.

As will be described in greater detail below, the mounting device 16 is a rocker arm suspension assembly style hood front mount comprising at least one first mounting bracket 20 configured to be attached to the chassis 14, in particular the rail 18. In the arrangement 10, the mounting bracket 20 is directly attached to the chassis 14, in particular the rail 18. The mounting device 16 further comprises at least one second mounting bracket 22 which is attached to the first mounting bracket 20. The mounting bracket 22 is also referred to as an arm mount, wherein the mounting bracket 20 is also referred to as an additional mounting bracket. The mounting device 16 further comprises at least one lever arm 24 pivotably arranged on the second mounting bracket 22, wherein the lever arm 24 is configured to be pivotably connected with the hood 12. In the arrangement 10, the hood 12 is pivotably connected with the lever arm 24. As can be seen from Figs. 1 and 2, the mounting device 16 further comprises an elastically deformable device 26 supported on the lever arm 24 and the second mounting bracket 22, wherein the elastically deformable device 26 is configured to be elastically deformed by moving the lever arm 24 in relation to the second mounting bracket 22. In other words, by pivoting the hood 12 open and close, the lever arm 24 is pivoted in relation to the mounting bracket 22 thereby elastically deforming the elastically deformable device 26. Moreover, the lever arm is pivotably arranged on the second mounting bracket 22 by means of at least one bolted joint connection 28 comprising a bolt 30 held on the mounting bracket 22. The bolted joint connection 28 further comprises a sleeve 32 concentrically arranged on the bolt 30, the sleeve 32 surrounding the bolt 30 in its circumferential direction, wherein the lever arm 24 is pivotably arranged on the sleeve 32 which is also referred to as a compression limiter sleeve. The bolted joint connection 28 further comprises polymer bushings 34 by means of which the lever arm 24 is pivotably supported on the sleeve 32 and/or the mounting bracket 22. The polymer bushings 34 function as lubricious bushings, in particular polymer lubricious bushings so that the lever arm 24 can be rotated or pivoted particularly easily. The bolted joint connection 28 further comprises washers 36 and a nut 38 for mounting the bolted joint connection 28 on the mounting bracket 22.

As can be seen from Fig. 2, the lever arm pivots on the bolt 30 via the sleeve 32 acting as a compression limiter sleeve. The bolted joint connection 28 is mounted on the mounting bracket 22 and connected with the lever arm 24 by means of the bolt 30, the washers 36 and the nut 38, but the use of the compression limiter sleeve prevents fixation of lever arm 24 to the mounting bracket 22 thereby allowing the lever arm 24 to rotate freely. The polymer lubricious bushings 34 are pressed into an opening 40 of the lever arm 24, the opening 40 being also referred to as a lever arm pivot. The bolt 30 penetrates the opening 40 which is configured as a through opening, wherein the bushings 34 and the sleeve 32 are arranged at least partially in the opening 40 and thus in the lever arm 24. The bushings 34 are pressed into the lever arm pivot to reduce wear and friction as the lever arm 24 rotates under hood articulation. One end 42 of the lever arm 24 functions as a pivot 44 for the hood 12, the pivot 44 comprising an opening 46 by means of which the lever arm 24 can be pivotably connected with the hood 12. For example, the opening 46 is configured as a through opening into which a spherical bearing 48 is pressed, this spherical bearing 48 being retained by a geometry by the lever arm 24 on one side of the spherical bearing 48 and a retaining ring 50 on the other side of the spherical bearing 48. The spherical bearing 48 functions as a pivot point for the previously mentioned hood opening and closing. The other end 52 of the lever arm 24 is supported on the elastically deformable device 26 comprising spring elements 54 and bump stops 56.

For example, the spring elements 54 are configured as coil springs which are elastically deformed when opening and closing the hood 12. As can be seen in Fig. 2, the other end 52 of the lever arm 24 reacts against the spring elements 54 being compression coil springs working in parallel or in series during lever arm rotation. The bump stops 56 are used to locate the spring elements 54 inside the lever arm 24 and arm mount 22. This is accomplished by a pocket geometry in the lever arm 24 and arm mount 22 that encompasses a back face of a bump stop flange and outer diameter of said flange. The spring elements 54 also referred to as springs which are seated on a respective front face of the respective bump stop flange and two degrees of spring translation are fixed by locating the spring inner diameter to the outer diameter of the conical bump stop section. During installation these springs are compressed to achieve bump stop to bump stop contact. The bump stops 56 and the springs are positioned between the arm mount pockets and released to force the bump stops 56 into the pockets for retention. During severe hood articulation, the bump stops 56 also function to limit the lever arm travel. Once all of these components are assembled, they form a hood front mount assembly which can be seen in Fig. 3.

Two of these hood front mount assemblies are used in conjunction to function as a hood front mount. One is installed on the left-hand rail and the other is installed on the righthand rail of the chassis 14. The front mount assembly installed on the left-hand rail is referred to as the left hand front hood mount and the front mount assembly installed on the right-hand rail is referred to as the right-hand front hood mount. The left-hand and the right-hand front hood mount assemblies are symentrically opposite above the mirror plane defined by the commercial vehicles for/aft centre line and the XZ-plane. The left hand front hood mount assembly is installed on the mounting bracket 20 which is, for example, bolted to the rail 18.

A nut plate 58 (Fig. 4) and two bolts 60 are used to fasten the respective front hood mount assembly to the mounting bracket 20. The identically installation procedure is used for the right-hand front hood mount. The hood pivot is then fastened to the left-hand and right-hand front hood assemblies at the spherical bearing 48 of the lever arm 22 by means of, for example, a bolt and nut respectively.

In the following, a hood front mount operation will be described: During truck operation,

i.e. truck in motion, the front of the hood is allowed to travel a designed amount to accommodate a specific g-load range until the bump stops 56 engage and prevent excessive travel. The rear hood supports are treated as a pivot point for the hood 12 acquiring sufficient hold down force from the hood latches to prevent the rear of the hood 12 from braking contact with the rear supports. The ability for the hood 12 to move and not be rigidly connected to the chassis 14 of the front of the hood 12 reduces stress loads being transmitted into the hood 12 from the chassis 14. The ability of the hood 12 to travel is also a favourable characteristic under hood racking or rolling scenarios caused by chassis bending. With the hood 12 free to move independently of the chassis 14, the hood 12 does not have to flex to follow the chassis 14 during these events reducing the overall stress load going into the hood 12.

In the following, disassembly and servicing will be described: in order to disassemble the hood 12 from the front mount assembly for servicing or repair, a disassembler would install a bolt 62 (Fig. 6) of sufficient length through servicing pass through holes 64 in the arm mount, the bump stops 56 and the lever arm 24. The disassembler would then install a nut 66 onto the disassembly bolt 62 and tighten down the nut 66 and/or the bolt 62 until said springs have been compressed enough to achieve bump stop to bump stop contact or a sufficient amount of compression has been achieved for disassembly. This can be seen from Fig. 6. Once the springs have been compressed, the lever arm pivot bolt 30 can be undone and the lever arm 24 with the springs and bump stops 56 attached is removed from the arm mount. The necessary parts are then serviced and the hood front mount is reassembled by reversing the disassembly procedure.

In the following, a design process for determining system characteristics will be described: The ability to easily alter the stiffness of the hood front mount is a key benefit to its design. The hood front mount stiffness can be tuned to various hood weights by changing the compression springs to achieve the proper frequency response. The designed front hood frequency response is determined based on isolating the hood 12 from the first chassis mode. For proper isolation from a frequency, common practice is to be at least the square root of two below the frequency or adequately above. This is used to establish the initial hood front mount target frequency. For instance, if the first chassis mode is at X Hz, then the initial starting value for the hood front frequency response would be at approximately (X/^v'²) Hz. Based on the target frequency and hood weight, the required front mount stiffness is calculated in order to establish the initial spring rate starting point where F is the desired frequency, m is the mass of the hood at the front mount, and k_totai is the total spring rate. It is important to note that the hood front mount system incorporates four springs working in parallel, so the k_totai represents k*4. For instance, if the solved k value is Y Ibs/in, then the resultant spring rate is (Y/4) Ibs/in.

This spring rate is then later refined by more accurate 3D system model analysis and/or physical testing. The lever arm ratio is also a function of the resultant stiffness seen at the hood pivot. For instance, this invention uses a lever arm ratio of (R:1) and as a result of this, the total spring rate of (Y/2) Ibs/in at both LH and RH sides is ((Y/2)/R) Ibs/in at the hood pivot 74 (Fig. 5). Moreover, Fig. 5 shows a lever arm pivot point 72, a lever arm pivot arc 70 and a hood pivot point 68.

reference signs arrangement hood chassis mounting device rail mounting bracket mounting bracket lever arm elastically deformable device bolted joint connection bolt sleeve bushing washer nut pivot pivot pivot opening bearing retaining ring end spring element bump stop nut plate bolt bolt opening nut hood pivot point hood pivot arc lever arm pivot point hood pivot

Claims

1. A mounting device (16) for mounting a hood (12) on a chassis (14) of a commercial vehicle, the mounting device (16) comprising:

- at least one first mounting bracket (20) configured to be attached to the chassis (14);

- at least one second mounting bracket (22) attached to the first mounting bracket (20);

- at least one lever arm (24) pivotably arranged on the second mounting bracket (22), and configured to be pivotably connected with the hood (12); and

- an elastically deformable device (26) supported on the lever arm (24) and the second mounting bracket (22), and configured to be elastically deformed by moving the lever arm (24) in relation to the second mounting bracket (22).

2. The mounting device (16) according to claim 1, wherein the lever arm (24) is pivotably arranged on the second mounting bracket (22) by means of at least one bolted joint connection (28) comprising:

- a bolt (30) held on the second mounting bracket (22); and

- a sleeve (32) concentrically arranged on the bolt (30), the sleeve (32) surrounding the bolt (30) in its circumferential direction, wherein the lever arm (24) is pivotably arranged on the sleeve (32).

3. The mounting device (16) according to claim 2, wherein the bolted joint connection (28) comprises at least one polymer bushing (34) by means of which the lever arm (24) is pivotably supported on the sleeve (32) and/or the second mounting bracket (22).

4. The mounting device (16) according to any one of the preceding claims, wherein the elastically deformable device (26) is, with respect to its axial direction, supported at both of its ends on the second mounting bracket (22) at least indirectly, wherein the lever arm (24) is, in the axial direction of the elastically deformable device (26), supported on the elastically deformable device (26) at least indirectly between the ends of the elastically deformable (26) device.