FIELD OF INVENTION:
[001] The present subject matter described herein, relates to a vehicle construction and more particularly, relates to a front portion structure of a vehicle.
BACKGROUND AND PRIOR ART:
[002] In front portion structures of passenger cars, bending of hood lock cross-member (or member) and radiator upper cross-member is a prominent phenomenon around 150Hz. This phenomenon is mainly due to coupling of natural frequencies of radiator upper cross-member and hood lock member. Both the radiator upper cross-member and hood lock member have their natural frequency around 150 Hz. Further in conventional designs, the connection of the radiator upper cross member is with the side brace lamp support member. This causes the bending of brace lamp support member, and because of this, the engine mount assembly incurs a translation mode. In conventional designs, the radiator upper cross-member is a part of two-pillar front-end design, being added to those vehicles where height of upper front end is more. The radiator upper cross-member serves the purpose of radiator supporting member. In conventional design, radiator upper cross-member is spot-welded to the side lamp brace members.
[003] Further, tactile vibrations occur in low frequency range – 100 Hz to 200 Hz. Major reason for the tactile vibration is the low dynamic stiffness of the sensitive paths of vibration transfer. One of the sensitive paths for vibration transfer is the engine mount attachment point. The root cause for low dynamic stiffness in the engine mounts is the resonance of front end structure, i.e. coupling of natural frequencies of radiator upper cross-member and hood lock member explained earlier. Such tactile vibrations are undesirable, and decoupling of the natural frequencies of radiator upper cross-member and hood lock member is required.
[004] Conventional methods of reducing the aforesaid tactical vibrations include - increasing the thickness of panels / components near engine mount, and / or addition of mass damper at engine mount location or radiator upper cross-member location. A mass damper is a block of steel with vibration dampening properties. However, such methods are cost inclusive, increase weight of the vehicle, decrease fuel efficiency, and reduce overall effectiveness of the vehicle.
[005] Japanese Patent publication JP2017047748 provides a vehicle front part structure. The problem focus of the Japanese prior art includes - To provide a vehicle front part structure that suppresses vibration of a cabin without causing constraint in manufacturing, such as increase in the number of components and vehicle weight. The solution to the aforementioned problem provided - In the vehicle front part structure, adjusting shapes of beads 72A, 72B of a radiator support upper member 30 matches mount positions of front side members 12A, 12B of radiator support side members 28A, 28B with node positions of vehicle width direction vibration of the radiator support side members 28A, 28B in a frequency band containing a natural frequency of a vehicle body, thereby suppressing a vibration amount of the front side members 12A, 12B to suppress vibration of the cabin.
[006] The Japanese prior art provides beads on hood lock member to minimize the vibration travel to front side members and the suspension points in order to reduce the road noise. Hence, the structural and / or functional aspect of the solution provided by the prior art is different from the present disclosure. Moreover, the prior art solution includes a complex design and geometry, wherein the beads are provided to create a node point along the radiator support vertical member through particular height of bead such that the deformation at the joining area of front side member & radiator support vertical member is reduced.
OBJECTS OF THE INVENTION:
[007] The principal objective of the present invention is to provide a front portion structure of a vehicle, wherein decoupling of natural frequencies of different components is achieved for reducing tactile vibrations.
[008] Another object of the present subject matter is to provide a simple, cost effective, and efficiently designed front portion structure of the vehicle that is distinct from all conventional designs.
SUMMARY OF THE INVENTION:
[009] The present invention relates to a front portion structure of a vehicle. The front portion structure includes a frame, which includes a hood lock member, two lateral vertical side members, and a lower cross member; and a radiator upper cross member for supporting a radiator of the vehicle, the radiator upper cross member being coupled to an underside of the hood lock member, wherein, the radiator upper cross member includes a plurality of recessed beads along a width of the radiator upper cross member, wherein each recessed bead of the plurality of recessed beads includes a trapezoidal profile with a plurality of angular faces.
[0010] 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
[0011] 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:
[0012] Fig. 1 illustrates a conventional vehicle front chassis portion;
[0013] Fig. 2a illustrates a conventional frame of the front chassis portion of Fig. 1;
[0014] Fig. 2b illustrates a conventional radiator upper cross member of the conventional frame of Fig. 2a;
[0015] Fig. 3 illustrates a front portion structure of a vehicle according to an embodiment of the present disclosure;
[0016] Fig. 4a(i) illustrates a perspective view of the radiator upper cross member, and Fig. 4a(ii) provides an enlarged view of a portion of the radiator upper cross member of Fig. 4a(i) in accordance with an embodiment of the present disclosure;
[0017] Fig. 4b(i) illustrates another view of the radiator upper cross member, and Fig. 4b(ii) illustrates another enlarged view of a portion of the radiator upper cross member of Fig. 4b(i);
[0018] Figs. 5a and 5b illustrate respective sectional views of the radiator upper cross member of Fig. 4b(i) about sections A-A’ and B-B’ in accordance with an embodiment of the present disclosure;
[0019] Fig. 6 illustrates a graph pertaining to vibration performance of the engine mount portion with the conventional radiator upper cross member of Fig. 1 and the radiator upper cross member of Fig. 3;
[0020] Fig. 7 illustrates a graph pertaining to tactile vibrations transferred to a floor of the vehicle from the engine mount portion; and
[0021] Fig. 8 illustrates a graph pertaining to drive-point frequency response function (FRF) comparison between the front chassis portion of Fig. 1 and the front portion structure of Fig. 3.
[0022] 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:
[0023] The present disclosure presents embodiments for a front portion structure of a vehicle. The front portion structure includes a frame, which includes a hood lock member, two lateral vertical side members, and a lower cross member; and a radiator upper cross member for supporting a radiator of the vehicle, the radiator upper cross member being coupled to an underside of the hood lock member, wherein, the radiator upper cross member includes a plurality of recessed beads along a width of the radiator upper cross member, wherein each recessed bead of the plurality of recessed beads includes a trapezoidal profile with a plurality of angular faces.
[0024] 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.
[0025] 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.
[0026] Fig. 1 illustrates a conventional vehicle front chassis portion 100. The front chassis portion 100 defining an engine mount portion 102, a conventional frame 104 having a hood lock portion 106 supported on a plurality of side lamp brace members 108 coupled to a lower portion 110. The conventional vehicle front chassis portion 100 further includes a conventional radiator upper cross member 112 coupled to the plurality of side lamp brace members 108.
[0027] Fig. 2a illustrates the conventional frame 104 of the front chassis portion 100. As can be seen, the conventional radiator upper cross member 112, being coupled to the plurality of side lamp brace members 108, defines a length L substantially similar to a length L’ of the hood lock portion 106. Fig. 2b illustrates the conventional radiator upper cross member 112. As is understood from the background section, the conventional radiator upper cross member 112 being coupled to the plurality of side lamp brace members 108, includes low dynamic stiffness, and is thereby a sensitive path for transfer of tactile vibrations from the engine mount portion 102 towards floor of vehicle. The conventional design includes a bracket connected at the center of the radiator upper cross member 112. Further, design of the conventional frame 104 is prone to resonate due to coupling of natural frequencies of the hood lock portion 106, the plurality of side lamp brace members 108, and the conventional radiator upper cross member 112 in low frequency range – 100 Hz to 200 Hz, and further making the conventional radiator upper cross member 112 susceptible to high bending forces BF adjacent to the bracket.
[0028] Fig. 3 illustrates a front portion structure 300 of a vehicle according to an embodiment of the present disclosure. The front portion structure 300 includes a frame 302. The frame 302 which includes a hood lock member 304, two lateral vertical side members 306, and a lower cross member 308. The front portion structure 300 further includes a radiator upper cross member 310 for supporting a radiator (not shown) of the vehicle. In an embodiment, the radiator upper cross member 310 is coupled to an underside of the hood lock member 304.
[0029] Fig. 4a(i) illustrates a perspective view of the radiator upper cross member 310, and Fig. 4a(ii) provides an enlarged view of a portion of the radiator upper cross member 310 of Fig. 4a(i) in accordance with an embodiment of the present disclosure. Fig. 4b(i) illustrate another view of the radiator upper cross member 310, and Fig. 4b(ii) illustrates another enlarged view of a portion of the radiator upper cross member 310 of Fig. 4b(i). As shown in Figs. 4a(i)-4b(ii), the radiator upper cross member 310 includes a plurality of recessed beads 312 along a width W1 of the radiator upper cross member 310. In an embodiment, each recessed bead 312 of the plurality of recessed beads 312 includes a trapezoidal profile 314 with a plurality of angular faces 316. Further, the recessed beads 312 in the radiator upper cross member 310 may be defined at a fixed interval length, for example L1 mm. Alternatively, the recessed beads 312 may be defined at a variable interval length. Further, a width “X” mm, and a height “Y” mm associated with the recessed beads 312 may be varied based upon requirement. In an example, greater the height “Y” mm and the width “X” mm of the recessed beads 312, greater will be the decrease in section stiffness of the radiator upper cross member 310. In an example, the optimum dimensions of the recessed beads 312, and a number of the recessed beads 312 can be decided based on manufacturing feasibility and the amount of improvement required.
[0030] Figs. 5a and 5b illustrates respective sectional views of the radiator upper cross member 310 of Fig. 4b(i) about sections A-A’ and B-B’ in accordance with an embodiment of the present disclosure. Section B-B’ provides a parametric outline of the plurality of angular faces 316 associated with the recessed beads 312. In operation, provision of the recessed beads 312 along the radiator upper cross member 310 changes stiffness of the radiator upper cross member 310. Further, the recessed beads 312 lead to a variable section with alternate low and high stiffness zones throughout the profile which leads to reduction of overall stiffness of the radiator upper cross member 310.
[0031] With continued reference to Figs. 1-5b, difference between the constructional and structural features of the conventional frame 104 and the frame 302 can be easily derived. Further, construction, structure, and mounting of the radiator upper cross member 310 is different from the conventional radiator upper cross member 112. As mentioned earlier, provision of the recessed beads 312 changes the stiffness of the radiator upper cross member 310. Further, the recessed beads 312 provide a decoupling of natural frequencies of the radiator upper cross member 310 and the hood lock member 304 in the low frequency range of 100 – 200 Hz. This reduces resonance in the front portion structure (300), thereby enabling the radiator upper cross member 310 to provide optimum dynamic stiffness to the frame 302. Such decoupling further ensures that minimal tactile vibrations are transferred from the engine mount portion 102 towards the floor of the vehicle. In an example, an improvement in floor vibration sensitivity is achieved by the radiator upper cross member 310 in comparison to conventional radiator upper cross member 112, without any weight addition, which will lead to lesser tactile vibration felt by passenger / occupant of the vehicle.
[0032] Further, because of the plurality of angular faces 316 associated with the recessed beads 312, the bending forces BF (prevalent in the conventional radiator upper cross member 112) are reduced due to change in stiffness and its natural frequency is decoupled from the hood lock member 304. Due to this phenomenon, less vibration is generated in the radiator upper cross member 310 as compared to that of vibrations generated in the conventional radiator upper cross member 112.
[0033] Fig. 6 illustrates a graph 600 pertaining to vibration performance of the engine mount portion 102 with the conventional radiator upper cross member 112 and the radiator upper cross member 310. In an example, as seen in the graph 600, a difference of 4-5 dB in a frequency range of 135-160 Hz is achieved. In other words, level of vibration transfer from the engine mount portion 102 to the floor of the vehicle is reduced by 4-5 dB on employing the radiator upper cross member 310.
[0034] Fig. 7 illustrates a graph 700 pertaining to tactile vibrations transferred to a floor of the vehicle from the engine mount portion 102 with the conventional radiator upper cross member 112 and the radiator upper cross member 310. In an example, as seen in the graph 700, a 5-15 dB improvement in tactile vibrations experienced by the floor of the vehicle is achieved in a frequency range of 135-160 Hz.
[0035] Fig. 8 illustrates a graph 800 pertaining to drive-point frequency response function (FRF) comparison between the front chassis portion 100 and the front portion structure 300. The graph 800 indicates that amplitude level of vibration of the radiator upper cross member 310 is reduced as compared to that of the conventional radiator upper cross member 112. Further, natural frequency in the range of 130 Hz to 140 Hz gets eliminated due to the recessed beads 312 design of the radiator upper cross-member 310. With change in stiffness of the radiator upper cross-member 310, natural behavior of the radiator upper cross-member 310 has changed. Due to the lesser displacement of the hood lock member 304 and the radiator upper cross member 310, the lateral movement of lateral vertical side members 306 in BL direction is avoided, which in turn prevents the bending of RH engine mount assembly.
[0036] Further advantages of employing the radiator upper cross member 310 include an increase in occupant comfort, weight saving due to non-increase of thickness or addition of mass dampers, increase in fuel efficiency, etc.
[0037] 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 front portion structure (300) of a vehicle, the front portion structure (300) comprising:
a frame (302), which includes a hood lock member (304), two lateral vertical side members (306), and a lower cross member (308); and
a radiator upper cross member (310) for supporting a radiator of the vehicle, the radiator upper cross member (310) being coupled to an underside of the hood lock member (304),
wherein, the radiator upper cross member (310) includes a plurality of recessed beads (312) along a width (W1) of the radiator upper cross member (310), wherein each recessed bead (312) of the plurality of recessed beads (312) includes a trapezoidal profile (314) with a plurality of angular faces (316).
2. The front portion structure (300) as claimed in claim 1, wherein the recessed beads (312) in the radiator upper cross member (310) are defined at a fixed interval length (L1) or a variable interval length.
3. The front portion structure (300) as claimed in claim 1, wherein a width (X), a height (Y), count, and positioning associated with the recessed beads (312) modifies a stiffness associated with the radiator upper cross member (310).
4. The front portion structure (300) as claimed in claim 3, wherein the recessed beads (312) lead to a variable section with alternate low and high stiffness zones throughout the profile which leads to reduction of overall stiffness of the radiator upper cross member (310).
5. The front portion structure (300) as claimed in claim 1, wherein decoupling of natural frequencies of the radiator upper cross member (310) and the hood lock member (304) along with reduction of bending forces (BF) is achieved in low frequency range based on the plurality of recessed beads (312).
6. The front portion structure (300) as claimed in claim 1, wherein the radiator upper cross member (310) provides optimum dynamic stiffness to the frame (302).