A reinforcement in automobile for reduction of vibration due to global body torsion mode
FIELD OF INVENTION
[001] This invention relates to a reinforcement in automobile for reduction of vibration due to global body torsion mode. The reinforcement is meant for the passenger cars in which vibration is caused due to global body torsion mode.

BACKGROUND/PRIOR ART

[002] In a passenger car, tactile vibration mainly on Floor and seat is encountered particularly at low frequencies in the order of 20 – 100 Hz. In many cases, it has been observed that the presence of a global body torsion mode nearby is responsible for the vibration as most of the global modes of a passenger car reside in the range of 20 – 100 Hz.

[003] Thus, a global body torsion mode comprises a situation in which the vehicle body is undergoing deformation as a whole, as such, vibration arising at any particular point, may or may not be at the maximum deformation zone of the global body torsion mode, in a vehicle can be attributed to that global mode occurring at the same or nearby frequency.

[004] The solution to the above problem in order to control tactile vibration owing to global body torsion mode constitutes improvement in the global body torsion mode. Said improvement is implemented by providing thicker section of body panel or additional structure in vehicle.

[005] The additional structure constitutes huge amount of reinforcement.

[006] The aforesaid adds to weight of vehicle and also demands alteration in design of vehicle.

[007] However, when the vibration is generated due to local mode. To counter the same, reinforcement is provided in the local area of vehicle.

[008] The reinforcement includes cross member and stiffener. For the same reference may be made to fig. 1 depicting reinforcement (R1) in front floor of vehicle and fig. 2 indicating reinforcement (R2) in rear floor of vehicle.

[009] In the first instance, deformation takes place in the front floor causing vibration thereat. In the second instance, the rear floor is deformed generating vibration on the rear floor itself.

[0010] Hence, reinforcement is added to the local area in order to take care of vibration.

[0011] In some cases, in order to dampen the vibration additional mass in the form of mel sheet is superimposed onto the floor of vehicle.

[0012] The global body torsion mode causes vibration in major portion of the part whereas local mode is confined to vibration in small area of vehicle part.

[0013] Solution to the abovementioned vibration problem relies on the following relation:-

[0014] Improving the stiffness shifts the natural frequency to a higher value; likewise increasing the mass would shift the natural frequency to a lower value as compared to the original natural frequency as evident from the relation.

[0015] Based on the combination of the two factors, the natural frequency shifts to either higher or lower value. Here, it is intended to decouple the natural frequency from the forcing frequency either by adding mass or improving stiffness.

Disadvantages associated with the aforesaid are as follows:

- Additional weight
- Reduced fuel efficiency
- Additional cost

[0016] Now, reference may be made to the following publications one by one for study.

[0017] A reinforcement structure of back door opening comprising a reinforcement in both round shaped area formed at a corner on rear of vehicle. The round shaped areas are formed at corners of the back door opening, which include rounded parts, side edge parts and lateral edges, wherein a reinforcement is placed on both sides between the inner panel and outer panel of rear pillar. The reinforcement extends from the side edge parts of the round shaped area to the lateral edges through the rounded parts.

[0018] In the above, reinforcements are provided so as to improve rigidity, which mandatorily requires welding.

[0019] In order to accommodate the reinforcement existing structure needs alteration, alternatively the same can be accommodated during manufacturing of the vehicle.

[0020] Another technology regarding opening part structure of vehicle rear part comprising a reinforcement so as to strengthen the hinge mounting area alongwith side corner.

[0021] To accommodate the above, change in existing structure is needed or it can be done at design stage.

[0022] This reinforcement only reinforces the hinge seat on the upper roof back so as to reduce stress concentration and improve strength.

[0023] Another disclosure introduces rear body structure for automobile, which includes an extended part of the backpillar reinforcement which is crossed with a drip recess and extended to a lateral-directional inside. The extended part is connected to a rear roofrail to provide adjacently the second closed cross section of a backpillar and a closed cross section of the rear roofrail.

[0024] The above leads to improvement in the coupling rigidity at the back door side corner area. However, it requires change in existing design completely.

[0025] Thus, none of the above fulfill the requirements for which the present invention has been devised.

OBJECTS OF THE INVENTION

[0026] An object of the invention is to propose a reinforcement in automobile for reduction of vibration due to global body torsion mode which obviates shortcomings of the prior arts.

[0027] Another object of the invention is to propose a reinforcement in automobile for reduction of vibration due to global body torsion mode which is simple in construction and can be added with minor changes in the existing structure.

[0028] Still another object of the invention is to propose a reinforcement in automobile for reduction of vibration due to global body torsion mode which is efficient.

[0029] Further object of the invention is to propose a reinforcement in automobile for reduction of vibration due to global body torsion mode which leads to improvement in customer comfort.

SUMMARY OF INVENTION

[0030] According to this invention, there is provided a reinforcement in automobile for reduction of vibration due to global body torsion mode comprising a single curved structure having a substantially L-section which is secured to backdoor upper corner area in weld body of vehicle.

[0031] The reinforcement can be a hollow structure or a solid member.

[0032] The reinforcement is preferably provided with a circular section, which is secured to the roof panel and lower panel in the corner area on both sides of vehicle by means of fastener such as clamp.

[0033] The clamp remains intact with mounting surface and is stiff enough to transfer load of reinforcement to the vehicle body without being deformed.

[0034] According to one embodiment of invention, the reinforcement is disposed being in contact with inner surface of the roof panel and lower panel facing cabin area of vehicle.

[0035] In accordance with another embodiment of invention, the reinforcement is placed in the space confined between the roof, roof panel, side body outer panel and lower panel of the vehicle.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

[0036] Further objects and advantages of this invention will be more apparent from the ensuing description when read in conjunction with the accompanying drawings of exemplary embodiments of invention and wherein:

Fig. 1 shows: Conventional front floor reinforcement in a vehicle for reduction of vibration due to local mode.
Fig.2 shows: Provision of rear floor reinforcement in automobile to reduce vibration due to local mode in prior art.
Fig. 3 shows: A reinforcement in passenger car for reduction of vibration due to global body torsion mode according to the present invention.
Fig. 4 shows: Reinforcement of invention assembled on the vehicle.
Fig. 5 shows: First embodiment of the present invention.
Fig.6 shows: Second embodiment in accordance with the invention.
Fig. 7A shows: CAE results for the prototype vehicle for floor vibration.
Fig. 7B shows: Physical testing results for the prototype vehicle for floor vibration.

DETAIL DESCRIPTION OF THE INVENTION WITH REFERENCE TO THE ACCOMPANYING DRAWINGS:

[0037] The present invention pertains to reinforcement in passenger car for prevention of vibration caused due to global body torsion mode.

[0038] The reinforcement is provided in the form of a metallic member having a curved structure which is secured to the weak zone of the vehicle to improve tactile vibration i.e. vibration particularly on floor and seat owing to global body torsion mode.

[0039] Now, reference may be made to fig. 3 illustrating reinforcement (1) of the invention together with fastening means (2) at both ends thereof.

[0040] The reinforcement constitutes a hollow tubular member preferably having circular section without restricting scope of the invention to the same. The circular section is preferred over other shape of sections due to its easy availability in the market and manufacturing feasibility.

[0041] According to another embodiment of the invention, the reinforcement forms a solid curved member preferably possessing a circular section for the reason already mentioned.

[0042] The reinforcement is having a substantially L-section as shown.

[0043] The abovediscussed reinforcement is secured to the backdoor upper corner area in weld body on both sides of vehicle as best seen in fig. 4, wherein the reinforcement is attached to each of the corner areas by means of a clamp (2) at both ends of said reinforcement as shown.

[0044] The reinforcement can be positioned at the back door upper corner area in the following ways.

[0045] Now, reference may be made to fig. 5 depicting positioning of the reinforcement from outside of the vehicle.

[0046] According to this aspect of the invention, the reinforcement is disposed being in contact with the roof panel (3) and lower panel (4) that one of vertical and horizontal parts of the reinforcement adheres to the roof panel and another part of said reinforcement establishes contact with the lower panel. The fillet part connecting horizontal and vertical parts of the reinforcement remains in touch with the portion of corner area of vehicle connecting the roof panel to the lower panel as shown in the figure.

[0047] Thus, the reinforcement runs parallel to the corner area and establishes contact with the inner surface of the roof panel (3) and lower panel (4) facing cabin area of vehicle.

[0048] The reinforcement is fastened to the corner area. The fastening means such as clamp should be stiff enough to transfer load of the reinforcement to the vehicle body without undergoing deformation.

[0049] Further, the clamp should be intact with surface of mounting.

[0050] From the sectional view A-A, further it can be noticed that the reinforcement (1) is next to the inner reinforcement (R) adjacent to the outer panel (6). The inner reinforcement (R) is provided between inner and outer panel of last pillar (C/D) of vehicle.

[0051] For another aspect of the invention, reference may be made to fig. 6 illustrating reinforcement from inside.

[0052] Here, the reinforcement is positioned in the space created between the roof (Not shown) mounted on the top, said roof panel, side outer panel and lower panel.

[0053] Hence, it is covered from all sides and clamped to the roof panel and lower panel from inside as shown.

[0054] From the sectional view (A-A), it can be understood that the reinforcement (1) is located between inner reinforcement (R) and outer panel (6) in a closed section.

[0055] The reinforcement is located in proximity to the edge of the corner area of the vehicle.

[0056] Thus, the present invention leads to improvement in the floor/seat vibration of vehicle with minor modification to the existing structure and with addition of less amount of weight as compared to known art.

[0057] The reinforcement can be made of steel by the method of stamping and rolling without restricting scope of the invention to the same. Thus, other materials and methods readily apparent to a person skilled in the art are understood to be within purview of the invention.

[0058] Now, reference may be made to fig. 7A and 7B regarding floor vibration result (CAE Vs Physical Testing). From the same it is evident that there is significant reduction in the floor vibration at problem frequency.

[0059] Fig. 7A is a CAE plot between frequency (Hz) (X-axis) and floor vibration (dB) (Y-axis) and fig. 7B shows a Test result plot between revolutions/min.(X-axis) and floor vibration (dB) (Y-axis).

[0060] Advantageous Features:-

- Light in weight
- Cost effective
- Improved fuel efficiency of vehicle comparatively
- Improved tactile vibration with minor alternation to the existing design
- Ease of implementation at any stage of vehicle development due to simpler design and mounting characteristics
- Enhancement in customer comfort
- Facilitates manufacturing due to simplicity in design.

[0061] It is to be noted that the present invention is susceptible to modifications, adaptations and changes by those skilled in the art. Such variant embodiments employing the concepts and features of this invention are intended to be within the scope of the present invention, which is further set forth under the following claims:-

Claims:WE CLAIM:
1.A reinforcement in automobile for reduction of vibration due to global body torsion mode comprising a single curved structure having a substantially L-section which is secured to backdoor upper corner area in weld body of vehicle.
2.The reinforcement in automobile for reduction of vibration due to global torsion mode as claimed in claim 1 wherein the reinforcement is a hollow structure.

3.The reinforcement in automobile for reduction of vibration due to global body torsion mode as claimed in claim 1 or 2 wherein the reinforcement forms a solid member.
4.The reinforcement in automobile for reduction of vibration due to global body torsion mode as claimed in any of the preceding claims wherein the reinforcement is preferably provided with a circular section, which is secured to the roof panel and lower panel in the corner area on both sides of vehicle by means of fastener such as clamp.

5. The reinforcement in automobile for reduction of vibration due to global body torsion mode as claimed in any of the preceding claims wherein the clamp remains intact with mounting surface and is stiff enough to transfer load of reinforcement to the vehicle body without being deformed.
6.The reinforcement in automobile for reduction of vibration due to global body torsion mode as claimed in any of the preceding claims wherein the reinforcement is disposed being in contact with inner surface of the roof panel and lower panel facing cabin area of vehicle.
7.The reinforcement in automobile for reduction of vibration due to global torsion mode as claimed in any of the preceding claims wherein the reinforcement is placed in the space confined between the roof, roof panel, side outer panel and lower panel of the vehicle.

8. The reinforcement in automobile for reduction of vibration due to global body torsion mode as claimed in any of the preceding claims wherein the reinforcement is located in proximity to the edge of the corner area of the vehicle.

9. The reinforcement in automobile for reduction of vibration due to global body torsion mode as claimed in any of the preceding claims is associated with the advantageous features such as herein described.
10.The reinforcement in automobile for reduction of vibration due to global body torsion mode substantially as herein described with reference to the accompanying drawings.