FIELD OF INVENTION:
[001] The present subject matter described herein, relates to front end structure of a vehicle, and, in particular, to a structure of hood cross member for improving radiator mounting vibrations in the vehicle.
BACKGROUND AND PRIOR ART:
[002] Radiators are heat exchangers which are used for cooling internal combustion engine in the vehicles. Generally, the radiators are mounted in front of the vehicle where there is no blockage of cool air to the atmosphere. The radiators dissipate the heat of the engine to the atmosphere and cool the engine. The radiators have various components, such as pump, fins, coolant which increases the weight of the radiator. Generally, radiators are made of steel or metal. Therefore, the radiator is typically a heavy component that requires solid support for the retention of the radiator assembly. Typically, a plurality of metal brackets are welded/bolted to a vehicle frame, specifically to hood cross members, lower and upper cross member; and the radiator assembly is attached thereto by threaded fasteners.
[003] In the existing radiator support structure, the radiator has its bottom portion mounted on a lower cross member by means of brackets and resilient members, while the radiator has, at its upper portion, formed with boss portions fitted into respective, resilient cylindrical shaped members which are mounted to an upper cross member by means of brackets and resilient members.
[004] Technical Problem: During running and operations of the radiator, it causes noise and vibrations in the vehicle. The noise and vibration created in the radiator enters into the vehicle cabin through mounting of radiator on the vehicle body panel and side lamp braces. Further, the occupant of the vehicle can feel the vibrations of the radiator on the floor and steering inside the cabin. Furthermore, the vibrations make the occupant of the vehicle un- comfortable.
[005] Fig. 1 illustrates structure and thickness of radiator mounting bracket for mounting radiator as known in the art. In the present engagement 100, radiator 104 is mounted on the front side of the vehicle. The radiator 104 is mounted on upper cross member 106 at the upper side and on the lower cross member 108 from lower side. The radiator 104 is mounted with the metal bracket on the upper and the lower cross members of the vehicle body. In this arrangement, thickness of the radiator mounting bracket 102 is increased to reduce the vibrations and noise. For example, thickness of the radiator mounting bracket 102 is increased from 2mm to 5mm. Increment in the thickness increases the weight and cost of structure. Further, it increases possible deterioration at other frequencies. Furthermore, addition of weight reduces the fuel efficiency of the vehicle.
[006] In another arrangement, thickness of the upper cross member is increased to reduce the noise and vibration, as illustrated in the figure 2. In the figure 2, thickness of the hood cross member or upper cross member is increased. Further, thickness may vary according to the size and dimension of the vehicle.
[007] Yet another arrangement, as illustrated in the figure 3, a new cross member 110 is added on the upper cross member 106. Further, the radiator 104 is directly mounted on the new cross member 110 without any mounting bracket. Though it reduces the requirement of mounting bracket and problem related with the mounting bracket, but it increases the cost of radiator mounting and weight of the arrangement which ultimately increases the cost and fuel consumption.
[008] Though the above mentioned prior art reduces the vibrations and noise in the vehicle as they are intended for, but each has its own drawbacks and limitations. The disadvantage in the above mentioned prior arts is that it increases weight and cost of the radiator mounting which ultimately increase the fuel consumption. Therefore, a simple, inexpensive, and effective solution is required for reduction of vibration in the vehicle while maintaining the weight and stiffness of the hood cross member.
OBJECTS OF THE INVENTION:
[009] The principal object of the present invention is to provide a front/hood cross member for reduction in vibration and noise in the vehicle.
[0010] Another object of the present subject matter is to provide a bead structure in the hood cross member for reduction in vibration and noise in the vehicle.
[0011] Another object of the present subject matter is to provide a bead structure at the weakest region to increase stiffness and increased stiffness shifts the natural frequency to higher value which ultimately reduces the vibrations and noise in the vehicle.
[0012] Yet another object of the present invention is to provide a bead structure in the hood cross member which is simple, inexpensive, strong, and efficient to reduce vibrations and noise without increasing weight, cost and fuel consumption of the vehicle.
SUMMARY OF THE INVENTION:
[0013] The subject matter disclosed herein relates to a structure of hood cross member with optimized bead structure for improving the radiator mounting and reducing the radiator mounting bracket vibrations in a vehicle. In the present structure of the hood cross member, an optimized bead structure is provided at the weakest location to improve the vibration performance at the problem frequencies. The addition of the bead structure at the weakest location/region increases the stiffness and there by shifts the natural frequency of the hood cross member to high value. The bead structure in the hood cross member reduces the vibration level at the mounting location along with the reduction in vibration level in the floor. Further, addition of the bead structure to the hood cross member does not increase the weight and cost of the hood cross member.
[0014] In order to further understand the characteristics and technical contents of the present subject matter, a description relating thereto will be made with reference to the accompanying drawings. However, the drawings are illustrative only but not used to limit scope of the present subject matter.

BRIEF DESCRIPTION OF THE DRAWINGS
[0015] It is to be noted, however, that the appended drawings illustrate only typical embodiments of the present subject matter and are therefore not to be considered for limiting of its scope, for the invention may admit to other equally effective embodiments. The detailed description is described with reference to the accompanying figures. In the figures, the left-most digit(s) of a reference number identifies the figure in which the reference number first appears. The same numbers are used throughout the figures to reference like features and components. Some embodiments of system or methods in accordance with embodiments of the present subject matter are now described, by way of example, and with reference to the accompanying figures, in which:
[0016] Fig. 1 illustrates structure and thickness of radiator mounting bracket for mounting radiator as known in the art;
[0017] Fig. 2 illustrates structure and thickness of hood cross member as known in the art;
[0018] Fig. 3 illustrates structure of new cross member additionally and radiator directly mounted on the cross member without any bracket as known in the art;
[0019] Fig. 4 illustrates structure of cross member with bead structure, in accordance with an embodiment of the present subject matter;
[0020] Fig. 5 illustrates mounting and cross sectional views of the bead structure on the cross section, in accordance with an embodiment of the present subject matter;
[0021] Fig. 6a illustrates cross section AA, in accordance with an embodiment of the present subject matter;
[0022] Fig. 6b illustrates cross section BB of the bead structure on the cross member, in accordance with an embodiment of the present subject matter;
[0023] Fig. 7 illustrates vibration performance of the radiator mounting location, in accordance with an embodiment of the present subject; and
[0024] Fig. 8 illustrates vibration transfer function of radiator mounting location on floor of the vehicle, in accordance with an embodiment of the present subject matter.
[0025] The figures depict embodiments of the present subject matter for the purposes of illustration only. A person skilled in the art will easily recognize from the following description that alternative embodiments of the structures and methods illustrated herein may be employed without departing from the principles of the disclosure described herein.
DESCRIPTION OF THE PREFERRED EMBODIMENTS:
[0026] The subject matter disclosed herein relates to a structure of hood cross member with optimized bead structure for improving the radiator mounting bracket vibration performance in a vehicle. In the present structure of the hood cross member, an optimized bead structure is provided at the weakest location to improve the vibration performance at problem frequencies. The addition of the bead structure at the weakest location/region increases the stiffness and there by shifts the natural frequency of the radiator mounting location to high value. The bead structure in the hood cross member reduces the vibration level at the mounting location along with the reduction in vibration level inside cabin. Further, addition of the bead structure to the hood cross member does not increase the weight and cost of the hood cross member.
[0027] It should be noted that the description and figures merely illustrate the principles of the present subject matter. It should be appreciated by those skilled in the art that conception and specific embodiment disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the present subject matter. It should also be appreciated by those skilled in the art that by devising various arrangements that, although not explicitly described or shown herein, embody the principles of the present subject matter and are included within its spirit and scope. Furthermore, all examples recited herein are principally intended expressly to be for pedagogical purposes to aid the reader in understanding the principles of the present subject matter and the concepts contributed by the inventor(s) to furthering the art, and are to be construed as being without limitation to such specifically recited examples and conditions. The novel features which are believed to be characteristic of the present subject matter, both as to its organization and method of operation, together with further objects and advantages will be better understood from the following description when considered in connection with the accompanying figures.
[0028] These and other advantages of the present subject matter would be described in greater detail with reference to the following figures. It should be noted that the description merely illustrates the principles of the present subject matter. It will thus be appreciated that those skilled in the art will be able to devise various arrangements that, although not explicitly described herein, embody the principles of the present subject matter and are included within its scope.
[0029] Fig. 4 illustrates structure of cross member with bead structure, in accordance with an embodiment of the present subject matter. The present hood cross member 400 is in ‘U’ shape and made from a single mold. The hood cross member 400 is made of steel material having high stiffness and durability. The hood cross member 400 is attached with the crash boxes at the front end of the vehicle. The hood cross member 400 is extended along the width of the vehicle at front end of the vehicle. The hood cross member 400 has several mounting holes to mount the hood cross member 400 on the front end of the vehicle. Further, the hood cross member 400 has two mounting holes 404 at a distance to mount radiator using radiator mounting bracket. A bead structure 402 is provided near the one mounting hole 404 which is on left hand side to increase stiffness of the area to eliminate the vibrations and noise in the radiator mounting.
[0030] In another embodiment, a plurality of bead structure can be provided near the mounting hole 404 to increase the stiffness of the area. Further, the present subject matter is not limited to single bead structure near one mounting hole. One or more than one bead structure can be provided near the left hand side and right hand side mounting holes. For example, the right hand side mounting hole can have one or more than one bead structure. Therefore, the present subject matter covers both the mounting holes and any number of bead structures around the mounting holes. For the clarity and better explanation of the present subject matter, a bead structure is provided near one mounting hole.
[0031] The bead structure 402 is provided across upper and bent surface of the U shaped hood cross member 400. Further, the U shaped hood cross member 400 has extended flanges at edges, the bead structure 402 is also provided on the edges to give necessary stiffness to the mounting hole. In the vehicles, operation of the radiator causes vibration related problems. The reason for the vibration and noise is the resonance of structural panels which are attached to the radiator, i.e., mounting brackets, hood cross member, sub frame and side lamp braces, through which the vibration forces of the radiator enters into the vehicle cabin. The natural frequency of the structural panels match with the excitation force frequency of the radiator which causes vibrations. By providing an optimized bead structure on hood cross member having no weight addition increases the stiffness of the hood cross member and shifts the natural frequency to higher values.
[0032] Fig. 5 illustrates the vertical B-B and horizontal A-A cross sectional views of the bead structure 402 on the hood cross member 400. Further fig. 6a illustrates the horizontal cross section AA of the bead structure 402 on the hood cross member. Where ‘W’ illustrates the width of the bead structure 402 and ‘H’ illustrates the height of the bead structure 402. The bead structure 402 has iteration 702 that is protruded from the base 704 (which is without bead) of the hood cross member 400. When no bead structure is provided the base 704 is flat. Fig. 6b illustrates the vertical cross section B-B of the bead structure with non bead structure. In the figure, 702 illustrates the iteration on the hood cross member with the bead structure. Further, the 704 illustrates the base surface without the bead structure. The size, i.e., height and width of the bead structure 402 can be optimized to improve the vibration performance at the problem frequencies. Furthermore, the bead structure 402 can be optimized as per the vehicle dimensions and requirements.
[0033] The weakest region of hood cross member 400 is identified by analyzing the strain energy concentration of the mode shape at the problem frequency. After analyzing location, the bead structure can be made near to that location depending on the feasibility. Addition of the bead structure at the weakest region increases the stiffness and there by shifts the natural frequency to higher value and reduces the amplitude of vibration of radiator mounting location. To reduce vibrations in the radiator mounting, natural frequency of mounting location of the hood cross member must be different from the problem frequency so that it does not get coupled with frequency of the excitation force. Natural frequency phenomena follows the below relation:
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[0034] Where fn is natural frequency, k is stiffness, and m is mass. The natural frequency lowers when stiffness is low and mass is more. By addition of the bead structure at the identified weakest region increases the stiffness and there by shifts the natural frequency to higher value and reduces the amplitude of vibration of radiator mounting location.
[0035] Several tests are conducted to check the feasibility and stability of the bead structure on the hood cross member for mounting of radiator. Fig. 7 illustrates vibration performance of the radiator mounting location, in accordance with an embodiment of the present subject matter. From the radiator mounting location vibration performance, the bead structure 402 resulted in 3.5 dB improvement in vibration performance of the radiator mounting location from base to bead structure with shift in frequency from 291 Hz to 299 Hz.
[0036] Fig. 8 illustrates vibration transfer function of radiator mounting location on floor of the vehicle, in accordance with an embodiment of the present subject matter. The vibration transfer function is performed to find sensitivity of the transfer path from radiator towards floor and steering vibrations. The test was conducted with the bead structure and without bead structure. By addition of the bead structure resulted in ~4 dBA improvement in floor vibration level through the path of radiator mounting location in the range of 280 Hz to 360Hz.
[0037] By the implementation of the optimized bead structure at the weakest region increases the stiffness shifts the natural frequency to higher value and reduces the amplitude of vibration of the radiator mounting location. By implementation of the bead structure improve the vibration performance without adding weight and cost. Subsequently, perceivable reduction in vibration level (up to -3.5dBA) at the mounting location along with reduction in vibration level inside cabin is achieved with weight and cost saving as compared to conventional solutions.. The bead structure in the hood cross member improves the vibration performance of the floor and steering. It increases the customer comfort level. Implementations of the bead structure on the hood cross member saves the weight upto 100% as compared to conventional solutions. Further, the structure of the bead is simple for manufacturing feasibility.
[0038] Although embodiments for the present subject matter have been described in language specific to structural features, it is to be understood that the present subject matter is not necessarily limited to the specific features described. Rather, the specific features and methods are disclosed as embodiments for the present subject matter. Numerous modifications and adaptations of the system/component of the present invention will be apparent to those skilled in the art, and thus it is intended by the appended claims to cover all such modifications and adaptations which fall within the scope of the present subject matter.

Claims:We claim:
1. A hood cross member (400) for reducing vibration and noise at mounting location of radiator (106), the hood cross member (400) comprising:
a plurality of mounting holes (404) for mounting the radiator (106) on the hood cross member (400); and
a bead structure (402) is provided at weakest location near any of mounting hole from the plurality of mounting holes (404) to increase stiffness and to shift natural frequency of the hood cross member (400) for reducing the vibration and noise.
2. The hood cross member (400) as claimed in claim 1, wherein the hood cross member (400) is in U shape.

3. The hood cross member (400) as claimed in claim 1, wherein the bead structure (402) has no extra weight and material.

4. The hood cross member (400) as claimed in claim 1, wherein the bead structure (402) can be any shape.

5. The hood cross member (400) as claimed in claim 1, wherein the bead structure (402) has optimized dimensions, wherein the optimized dimensions are based on the vehicle.

6. The hood cross member (400) as claimed in claim 1, wherein the hood cross member (400) is made of metal.

7. The hood cross member (400) as claimed in claim 1, wherein the weakest location near the mounting holes (404) is identified using strain energy concentration.

8. The hood cross member (400) as claimed in claim 1, wherein the hood cross member (400) has more than one bead structure (402) for stiffness.