JP2013241041A - Vehicle front body structure - Google Patents

Abstract

An object of the present invention is to reduce unpleasant noise generated in a vehicle interior due to vibration transmitted from a front suspension to a vehicle body side through a front subframe.
In a vehicle body front structure in which suspension arms are supported on left and right front side frames 4 via a front subframe 5, the front subframe includes left and right vertical members 21 extending in the longitudinal direction of the vehicle body. The front and rear horizontal members 22 and 23 extending in the left-right direction of the vehicle body are formed in a substantially rectangular shape in plan view, and the left and right vertical members have arm support portions 45 that support suspension arms, In a front view, the cross member 61 extending in the left-right direction of the vehicle body is connected to the front end portions of the side frames, and the left and right end portions of the cross member and the central portion of the front lateral member are connected to each other. A brace 62 arranged to form a V shape is provided.
[Selection] Figure 5

Description

  The present invention relates to a vehicle body front structure in which a suspension arm is supported via front subframes on left and right front side frames extending forward from a dashboard panel.

  As a vehicle front structure of an automobile, there is a structure in which a front subframe is attached below the left and right front side frames extending forward from the dashboard panel and a suspension arm is supported on the front subframe. .

  In such a configuration, when the vehicle travels, vibration is input to the arm support portion that supports the suspension arm in the front subframe, and this vibration constitutes the vehicle body skeleton including the front side frame from the front subframe. It is transmitted to the dashboard panel via a member that causes the dashboard panel to vibrate in the front-rear direction, and further, the vibration is transmitted to a surface member such as a floor panel or a window glass, thereby generating noise (road noise) in the vehicle interior. Cause it to occur. Especially when driving on rough roads, low- and medium-frequency (about 100-500 Hz) vibrations are transmitted, and the noise generated in the passenger compartment gives passengers discomfort. However, there is a problem in improving the merchantability.

  In order to reduce the noise in the passenger compartment when the vehicle is traveling, a technique is known in which a bead serving as an elastic bending point is provided at a position near the vehicle body side member in the front cowl. In this technique, the vibration transmitted from the vehicle body side member to the front cowl is blocked by the bead, whereby the vibration transmitted from the vehicle body side member to the dashboard panel via the front cowl can be suppressed.

JP 2010-228718 A

  However, in the conventional technique, the transmission of vibration on a specific vibration transmission path can be blocked by the bead, but the dashboard panel includes a side frame in addition to the upper member arranged on the side of the vehicle body. Vibration is input through the vibration transmission path, and the vibration transmission path that does not pass through the bead cannot be interrupted. In addition, even if a bead is provided, the state where the steel plate member is connected is not changed, and vibration energy is transmitted except for a specific frequency, so that the noise in the passenger compartment is sufficiently reduced. There was a problem that could not.

  The present invention has been devised to solve such problems of the prior art, and its main purpose is to bring the vehicle interior into the vehicle compartment by vibrations transmitted from the front suspension to the vehicle body via the front subframe. An object of the present invention is to provide a front body structure of an automobile configured to reduce unpleasant noise that occurs.

  A first invention made to solve the above problems includes a dashboard lower panel that partitions a vehicle compartment and an engine room, left and right front side frames that extend forward from the dashboard lower panel, and the front side frame. In a vehicle body front structure that includes a front subframe that is supported by a frame and that supports a suspension arm, the front subframe includes left and right vertical members that extend in the longitudinal direction of the vehicle body, and a left and right vertical member that extends in the lateral direction of the vehicle body. The left and right vertical members have arm support portions for supporting the suspension arms, and the front end portions of the left and right front side frames are mutually connected. A cross member extending in the left-right direction of the vehicle body in a manner connected to the left and right sides of the cross member A structure in which the arranged braces to form a V-shape in a front view with parts and manner of interconnecting the central portion of the transverse member of the front is provided.

  According to this, the rigidity of the front end of the vehicle body is enhanced by the cross member and the brace, so that vibrations in the three directions of the vertical direction, the horizontal direction, and the front-rear direction in the vicinity of the arm support portion of the front subframe and the entire subframe are suppressed. Can do. As a result, vibration energy input from the suspension arm to the vehicle body side is reduced, and at the same time, vibrations transmitted to the dashboard lower panel, floor panel, window glass, and other surface members via the front side frame are suppressed. Since vibration of the surface member can be suppressed, unpleasant noise generated in the passenger compartment can be reduced.

  According to a second aspect of the present invention, the cross member has a substantially rectangular cross section with front and rear side wall portions, an upper wall portion, and a lower wall portion, and the upper wall portion extends substantially straight in the left-right direction of the vehicle body. The lower wall portion extends obliquely downward toward the front side frame at both left and right ends, and the side wall portion gradually increases in width in the vertical direction of the vehicle body toward the front side frame. A widened portion is provided at both left and right ends, and the brace is joined to the widened portion.

  According to this, since the mounting area of the brace can be ensured by the widened portion of the cross member, the joining rigidity of the brace to the cross member can be increased. Since the braces are arranged in a V shape when viewed from the front, the front side frame and the front sub frame can be prevented from being deformed in the vertical direction and the horizontal direction. Transmission of vibration can be suppressed at the same time energy is reduced.

  According to a third aspect of the present invention, the upper end of the brace is fixed to the front surface of the cross member, and the lower end of the brace is fixed to the front of the lateral member via a bracket.

  According to this, since the braces can be arranged in a substantially vertical direction when viewed from the side, vibration energy input from the suspension arm to the vehicle body side is reduced, and at the same time, vibration in the vertical and horizontal directions from the suspension arm is suppressed. be able to.

  According to a fourth aspect of the present invention, a mounting portion to which the front sub-frame is coupled extends downward from a front end portion of the front side frame, and left and right end portions of the cross member are formed on an upper wall of the front side frame. It is set as the structure joined to the inner side wall part of the said attachment part formed in the state which followed the inner side wall part and this inner side wall part.

  According to this, since the cross member is joined to the front end portion of the front subframe with high rigidity, it is possible to suppress the vertical and horizontal deformations of the front side frame at the front end portion of the front side frame. The vibration transmission from can be further suppressed.

  In a fifth aspect of the invention, the cross member is a closed cross-sectional member having a substantially rectangular cross section, and the brace has a substantially hat-shaped cross section.

  According to this, since the cross member and the brace can be configured with a small cross-sectional area and high rigidity, it is possible to improve the strength and rigidity of the front end of the vehicle body without causing any trouble when the radiator is disposed forward. Thus, vibration transmission via the front end of the vehicle body can be suppressed, and steering stability and collision safety can be improved.

  As described above, according to the present invention, the rigidity of the front end of the vehicle body is increased by the cross member and the brace. Vibration can be suppressed. As a result, vibration energy input from the suspension arm to the vehicle body side is reduced, and at the same time, vibrations transmitted to the dashboard lower panel, floor panel, window glass, and other surface members via the front side frame are suppressed. Since vibration of the surface member can be suppressed, unpleasant noise generated in the passenger compartment can be reduced.

It is a perspective view which shows the vehicle body front part structure of the motor vehicle based on this embodiment. 4 is a bottom view of the front subframe 5 and the front suspension 6. FIG. 2 is a perspective view of a front subframe 5 and a front suspension 6. FIG. FIG. 2 is a longitudinal sectional view of the vehicle body front structure shown in FIG. 1 cut from a plane substantially orthogonal to the vehicle body left-right direction and viewed from the vehicle body left side. It is a perspective view which shows the vehicle body front end part in the vehicle body front part structure shown in FIG. FIG. 6 is a longitudinal sectional view of the front end portion of the vehicle body shown in FIG. 5 cut along a plane substantially orthogonal to the left-right direction of the vehicle body and viewed from the left side of the vehicle body. It is a perspective view which shows the bracket 75 in detail. FIG. 6 is a longitudinal sectional view of the front end portion of the vehicle body shown in FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a perspective view showing a front body structure of an automobile according to the present embodiment. The vehicle body front structure includes a dashboard lower panel 3 that partitions the engine room 1 and the vehicle compartment 2, left and right front side frames 4 that extend forward from the dashboard lower panel 3, and the front side frame 4. The front subframe 5 is supported, and a front suspension 6 is supported on the front subframe 5.

  Left and right upper frames 7 extending in the longitudinal direction of the vehicle body are provided outside the front side frame 4 in the vehicle width direction. A damper housing 8 and a wheel house 9 are provided between the front side frame 4 and the upper frame 7. A damper 33 for the front suspension 6 is accommodated in the damper housing 8. An attachment bracket 12 for attaching a bumper beam (not shown) is joined to each front end portion of the front side frame 4 and the upper frame 7.

  FIG. 2 is a bottom view of the front sub-frame 5 and the front suspension 6. FIG. 3 is a perspective view of the front subframe 5 and the front suspension 6.

  As shown in FIG. 2, the front sub-frame 5 has a substantially rectangular shape in plan view by left and right vertical members 21 extending in the vehicle body front-rear direction and front and rear horizontal members 22 and 23 extending in the vehicle body left-right direction. It is configured.

  As shown in FIG. 3, the front suspension 6 is of a so-called strut type, and includes a knuckle 31 that holds wheels (not shown), a suspension arm 32 that rotatably supports the knuckle 31, and a knuckle 31 that is supported. In addition, a damper (strut damper) 33 that generates a required damping force and a spring 34 that biases the damper 33 are provided.

  The knuckle 31 is provided with a damper connecting portion 35 to which a damper 33 is connected, a caliper support portion 36 for supporting a brake caliper (not shown), and a tie rod connecting portion 37 to which a tie rod (not shown) is connected. It has been. The upper end of the damper 33 is supported by the top wall portion of the damper housing 8. The damper 33 is provided with a stabilizer bracket 38, to which an end of the stabilizer 40 is connected via a stabilizer link 39. The stabilizer 40 is supported by the rear side member 23 in the front sub-frame 5 via the bracket 41.

  As shown in FIG. 2, the suspension arm 32 is a so-called A-type arm that is bifurcated from the pivotal support portion 42 of the knuckle 31, and has a front arm portion 43 and a rear arm portion 44. The left and right vertical members 21 in the front subframe 5 have arm support portions 45 and 46 that respectively support the front arm portion 43 and the rear arm portion 44 of the suspension arm 32.

  The front arm support portion 45 is provided at an intermediate position of the joint portion of the vertical member 21 with the front and rear horizontal members 22 and 23. The rear arm support portion 46 is provided at a position where the vertical member 21 is joined to the rear lateral member 23. The front arm portion 43 and the rear arm portion 44 are coupled to arm support portions 45 and 46 via elastic bushes 47 and 48, respectively (see FIG. 3).

  FIG. 4 is a longitudinal sectional view of the vehicle body front structure shown in FIG. 1 cut from a plane substantially orthogonal to the vehicle body left-right direction and viewed from the vehicle body left side. FIG. 5 shows the right side of the vehicle body, but the left side of the vehicle body appears approximately symmetrically.

  The front side frame 4 has an inclined portion 52 that extends obliquely upward from the rear end portion 51 on the rear side, and a horizontal portion 53 that extends in a substantially horizontal direction on the front side. A drooping portion 54 extending downward is provided at the front end of the horizontal portion 53.

  The front subframe 5 has connecting portions 55, 56, and 57 for the front side frame at a total of three locations, that is, the front end side and the rear end side of the left and right vertical members 21 and the middle thereof.

  The connecting portion 55 on the front end side is connected to a hanging portion 54 provided at the front end of the front side frame 4. The connecting portion 57 on the rear end side is connected to the rear end portion 51 of the front side frame 4. Each of the connecting portions 55 and 57 has a substantially horizontal mounting surface (see FIG. 3), and a substantially horizontal mounting surface is also formed on the side of the front side frame 4 facing this. The front subframe 5 and the front side frame 4 are fastened by, for example, screwing a bolt in a substantially vertical direction from the lower surface side of the front subframe 5 after abutting the mounting surfaces.

  On the other hand, the intermediate connecting portion 56 is connected to the front side frame 4 via brackets 58 and 59. The bracket 58 is joined in advance to the intermediate connecting portion 56, and the bracket 59 is joined in advance to the front side frame 4, and the bolts 60 are fitted in a substantially horizontal direction with these brackets 58, 59 fitted together. The brackets 58 and 59 are fastened together by screwing.

  FIG. 5 is a perspective view showing a vehicle body front end portion in the vehicle body front portion structure shown in FIG.

  The front end of the vehicle body includes a cross member 61 extending in the left-right direction of the vehicle body in such a manner that the front end portions of the left and right front side frames 4 are connected to each other. There is provided a brace 62 arranged so as to form a V shape in a front view in such a manner that the central portions of the horizontal members 22 are connected to each other.

  When the cross member 61 and the brace 62 are provided in this manner, the rigidity of the front end of the vehicle body is increased. Therefore, in the vicinity of the arm support portion 45 that supports the suspension arm 32 in the front subframe 5 and in the vertical direction of the entire front subframe 5, left and right The vibrations in the three directions of the direction and the front-rear direction can be suppressed. For this reason, vibration energy input from the suspension arm 32 to the vehicle body side is reduced, and vibration transmitted to the dashboard lower panel 3 and the surface members such as a floor panel and a window glass (not shown) via the front side frame 4 is suppressed. And since the vibration of those surface members can be suppressed, the low middle frequency road noise (100-500 Hz) which is the unpleasant noise which generate | occur | produces in a vehicle interior can be reduced.

  FIG. 6 is a longitudinal sectional view of the front end portion of the vehicle body shown in FIG. 5 taken along a plane substantially orthogonal to the left-right direction of the vehicle body and viewed from the left side of the vehicle body.

  The cross member 61 is a closed cross-section member having a substantially rectangular cross section by the front and rear side wall portions 64 and 65, the upper wall portion 66 and the lower wall portion 67. In particular, here, the flange portion 68 is formed so as to protrude from the upper wall portion 66 in the longitudinal direction of the vehicle body. The cross member 61 can be obtained by press forming a steel plate. For example, a member having a substantially hat-shaped cross section constituting the side wall portions 64 and 65, the lower wall portion 67, and the flange portion 68 is replaced with an upper wall portion 66 and a flange. It can be obtained by joining flat members constituting the portion 68.

  On the other hand, the brace has a substantially hat-shaped cross section by a bottom wall portion 71, upper and lower side wall portions 72, 73 and a flange portion 74. This brace can be obtained by press forming of a steel plate.

  If the cross member 61 and the brace 62 are configured in this way, the cross member 61 and the brace 62 can be configured with a small cross-sectional area and high rigidity, so that there is no hindrance when a radiator (not shown) is disposed forward. Thus, the strength and rigidity of the front end of the vehicle body can be improved, whereby vibration transmission via the front end of the vehicle body can be suppressed, and further, the steering stability and the collision safety can be improved. Can do.

  The upper end portion of the brace 62 is fixed to the front surface of the cross member 61, that is, the outer surface of the front side wall portion 64. On the other hand, the lower end portion of the brace 62 is fixed to the front side of the front side member 22 in the front subframe 5 via a bracket 75. In particular, here, the brace 62 is disposed such that the flange portion 74 is located on the front side, and the bottom wall portion 71 is joined to the cross member 61 and the lateral member 22.

  With this configuration, the brace 62 can be disposed in a substantially vertical direction when viewed from the side, so that vibration energy input from the suspension arm 32 to the vehicle body side can be reduced, and at the same time, the vertical and horizontal directions from the suspension arm 32 can be reduced. Can be suppressed.

  FIG. 7 is a perspective view showing the bracket 75 in detail. The bracket 75 has a substantially hat-shaped cross section by a bottom wall portion 91, left and right side wall portions 92, and a flange portion 93. A mounting surface 94 of the brace 62 is provided on the front surface of the bottom wall portion 91. The flange portion 93 is formed in an arcuate shape along the outer peripheral surface of the front side member 22 having a circular cross section, and the bent portion 95 of the flange portion 93 is joined to the front side member 22. .

  5, in the cross member 61, the upper wall portion 66 extends substantially straight in the left-right direction of the vehicle body, and the lower wall portion 67 is inclined downward toward the front side frame 4 at both left and right ends. The side wall portion 64 has widened portions 81 at the left and right ends that gradually increase in width in the vertical direction of the vehicle body toward the front side frame 4. The upper end is joined.

  By providing the widened portions 81 at the left and right ends of the cross member 61 in this way, a large mounting area of the brace 62 can be secured, so that the joining rigidity of the brace 62 to the cross member 61 can be increased. Since the brace 62 is arranged in a V shape when viewed from the front, the front side frame 4 and the front subframe 5 can be prevented from being deformed in the vertical direction and the horizontal direction. It is possible to reduce vibration energy input and simultaneously suppress vibration transmission.

  FIG. 8 is a longitudinal sectional view of the front end portion of the vehicle body shown in FIG. 5 taken along a plane substantially orthogonal to the longitudinal direction of the vehicle body and viewed from the front of the vehicle body.

  The front end portion of the front side frame 4 has inner and outer side wall portions 83, 84, an upper wall portion 85, and a lower wall portion 86, and is formed in a rectangular tube shape having a substantially rectangular longitudinal section. At the front end portion of the front subframe 5, as described above, the hanging portion (attachment portion) 54 to which the front end side connecting portion 55 of the front subframe 5 is connected is provided in a manner extending downward. Yes. The hanging portion 54 has inner and outer side wall portions 87, 88, a rear side wall portion 89, and a front side wall portion (not shown), and is formed in a rectangular tube shape having a substantially rectangular cross section. Yes. The inner side wall portion 87 of the hanging portion 54 is formed in a state of being continuous with the inner side wall portion 83 of the front subframe 5.

  The left and right end portions of the cross member 61 are provided with an upper wall portion 85 and an inner side wall portion 83 of the front side frame 4, and an inner side wall portion 87 of the hanging portion 54 formed in a state of being continuous with the inner side wall portion 83. It is joined to. As described above, the cross member 61 has the widened portions 81 whose width in the vertical direction of the vehicle body gradually increases at both left and right ends, and the widened portion 81 has a vertically long, substantially rectangular cross section. Thereby, the cross member 61 has a large cross-sectional area at a portion where the cross member 61 is joined to the front side frame 4 and the hanging portion 54, and the joining area to the front side frame 4 and the hanging portion 54 is also increased.

  With this configuration, since the cross member is joined to the front end portion of the front subframe with high rigidity, the front side frame 4 can be prevented from being deformed in the vertical and horizontal directions at the front end portion of the front side frame 4. Thus, vibration transmission from the suspension arm 32 can be further suppressed.

  In the present embodiment, as shown in FIG. 3, the strut type front suspension 6 has been described as an example. However, the present invention is not limited to such a type of front suspension, for example, a wishbone type suspension. It is also possible to apply to other types of front suspensions.

  Further, in the present embodiment, as shown in FIG. 5, the two braces 62 are arranged symmetrically so as to form a V shape, and each is fixed to the horizontal member 22 by two brackets 75. However, a configuration in which the brace is integrally formed in a V shape and is fixed to the lateral member 22 with a single bracket is also possible.

  In the present embodiment, as shown in FIG. 6, the brace 62 has a substantially hat-shaped cross section. However, the present invention is not limited to such a brace. A thing with a square-shaped closed section is also possible.

1 Engine compartment 2 Car compartment 3 Dashboard lower panel 4 Front side frame 5 Front subframe, 83, 84 Side wall portion, 85 Upper wall portion, 86 Lower wall portion 6 Front suspension 21 Vertical member 22 Front side member 23 Rear side Member 32 Suspension arm 43 Front arm portion 44 Rear arm portion 45, 46 Arm support portion 54 Hanging portion (mounting portion), 87, 88 Side wall portions 55, 56, 57 Connection portion 61 Cross member, 64, 65 Side wall portion, 66 Upper wall portion, 67 Lower wall portion 62 Brace, 71 Bottom wall portion, 72, 73 Side wall portion, 74 Flange portion 75 Bracket 81 Widened portion

Claims (5)

A dashboard lower panel that partitions the vehicle compartment and the engine room, left and right front side frames that extend forward from the dashboard lower panel, and a front subframe that is supported by the front side frame and supports the suspension arm In the front body structure of an automobile equipped with
The front sub-frame is configured in a substantially rectangular shape in plan view by left and right vertical members extending in the vehicle body front-rear direction and front and rear horizontal members extending in the vehicle body left-right direction,
The left and right vertical members have arm support portions that support the suspension arm,
A cross member extending in the left-right direction of the vehicle body in a manner to connect the front end portions of the left and right front side frames to each other;
An automobile having a brace arranged so as to form a V shape in a front view is provided in such a manner that the left and right end portions of the cross member and the central portion of the front lateral member are connected to each other. Body front structure.   The cross member has a substantially rectangular cross-section by front and rear side wall portions, an upper wall portion, and a lower wall portion, the upper wall portion extends substantially straight in the left-right direction of the vehicle body, and the lower wall portion is The left and right ends extend obliquely downward toward the front side frame, and the side wall portion has widened portions at the left and right ends that gradually increase in width in the vertical direction of the vehicle body toward the front side frame. The vehicle body front structure according to claim 1, wherein the brace is joined to the widened portion.   The upper end portion of the brace is fixed to the front surface of the cross member, and the lower end portion of the brace is fixed to the front of the lateral member via a bracket. Car body front structure. A mounting portion to which the front subframe is coupled extends downward from a front end portion of the front side frame,
The left and right end portions of the cross member are joined to an upper wall portion and an inner side wall portion of the front side frame, and an inner side wall portion of the attachment portion formed in a state of being continuous with the inner side wall portion. The vehicle body front part structure according to any one of claims 1 to 3, wherein The cross member is a closed cross-sectional member having a substantially rectangular cross section,
The vehicle body front part structure according to any one of claims 1 to 4, wherein the brace has a substantially hat-shaped cross section.

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