JP2009137543A - Front structure of vehicle body - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a front structure of a vehicle body for absorbing energy at a lower part of a vehicle more securely by securing a degree of freedom of engine layout of a sub-frame. <P>SOLUTION: The front structure 11 of the vehicle body is provided with the sub-frame 14 of a square frame shape for supporting front wheels and an engine which is attached to the vehicle body lower part. The sub-frame 14 has energy absorbing bar members (a left front first bar member 66, a right front first bar member 68, a left rear second bar member 72 and a right rear second bar member 74) attached for absorbing energy applied from outward at inside of a left front corner part 64, a right front corner part 67, a left rear corner part 71 and a right rear corner part 73. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a vehicle body front structure including a rectangular frame-shaped subframe that is attached to a lower portion of a vehicle body and supports an engine.

Some vehicle body front structures have a substantially cross-shaped reinforcing member disposed in the lower part of the engine room. The reinforcing members are attached to the left and right front frames with the engine cross members extending toward the left and right front wheels, joined to the radiator panel with the U-shaped frames facing both ends from the center of the engine cross members to the front, and the engine cross members There are some which are joined to the left and right front frames with both ends of the V-shaped frame facing from the center to the rear (see, for example, Patent Document 1).
Japanese Patent Laid-Open No. 11-157468 (page 7, FIG. 1)

  However, the front body structure of Patent Document 1 has a problem that the space under the engine is blocked by the engine cross member, the U-shaped frame, and the V-shaped frame, and the layout of the engine room is limited.

  An object of the present invention is to provide a vehicle body front structure that secures the degree of freedom of engine layout of a subframe, increases the strength of the subframe, and absorbs energy more reliably at the lower part of the vehicle.

  In the invention according to claim 1, in the vehicle body front part structure including the rectangular frame-shaped subframe that is attached to the lower part of the vehicle body and supports the front wheels and the engine, the subframes are arranged on the inner sides of the corners from the outside. An energy absorbing bar member for absorbing the applied energy is attached.

  In the invention according to claim 2, the subframe includes a left beam member positioned in the vicinity of the front wheel, a right beam member, a weakened portion formed at one end of the left beam member included in the corner, and a right beam member. And a weakened portion formed at one end.

  In the invention according to claim 1, since the energy absorption bar member that absorbs energy applied from the outside is attached to the inside of each corner portion of the subframe of the vehicle body front structure, the engine is arranged in the center of the subframe. Even if the engine is supported by the subframe, the engine and the energy absorbing bar member do not interfere with each other. Therefore, there is an advantage that the degree of freedom of the engine layout of the subframe can be ensured.

  Further, when the load is transmitted to the subframe, the load can be transmitted and dispersed by the energy absorbing bar member, and the strength of the subframe can be increased.

  Further, when the load is transmitted, the sub frame can transmit the load by the energy absorbing bar member, and can absorb the energy more reliably in the lower part of the vehicle.

  In addition, when the subframe has a front offset and a large load, for example, when a large load is applied only to the left, the left side of the vehicle body and the left of the subframe are deformed rearward, and the right side of one vehicle body is Although it turns to the left side, the right-side strength is also increased by the energy absorbing bar member on the right side of the subframe, which means that the resistance to bending on the right side of the vehicle body is increased, and the bending on the right side of the vehicle body can be suppressed. . Therefore, deformation toward the vehicle interior can be suppressed.

  In the invention according to claim 2, the subframe includes a left beam member positioned in the vicinity of the front wheel, a right beam member, a weakened portion formed at one end of the left beam member included in the corner, and a right beam member. A weak portion formed at one end, so that the load applied to the front surface of the vehicle is absorbed by the deformation of the weak portion, and when the load applied to the energy absorption bar member increases with the deformation of the weak portion, the energy absorption bar is further increased. There is an advantage that energy can be absorbed more by deformation of the member.

The best mode for carrying out the present invention will be described below with reference to the accompanying drawings.
FIG. 1 is a side view of a vehicle body front structure according to the present invention.
FIG. 2 is a perspective view of the vehicle body front part structure of the present invention, and shows a state viewed from below.

  The vehicle body front structure 11 is included in the vehicle body 13 of the vehicle 12, has a subframe 14 at the lower portion, and an energy absorption mechanism 15 is attached to the subframe 14.

The subframe 14 is used for the same purpose as the existing one, and supports the engine 21 and the front suspension 22 (see FIG. 5). Then, the vehicle body 13 is lifted from below the front body 23 as indicated by an arrow a1 and assembled to the lower part of the left front side frame 25 and the right front side frame 26 (vehicle body lower part 94). Details will be described later.
A front wheel 27 is supported on the front suspension 22 (see FIG. 5).

  The vehicle body 13 includes an underbody 31 that forms the floor of the passenger compartment 28, a left side body 32 provided to the left of the underbody 31, a right side body 33 provided to the right, and a front body 23 having an engine room 34 provided in front. I have.

  The underbody 31 includes a left side sill 36 that forms the left end, a left front floor frame 37 that extends along the left side sill 36, a right side sill 38 that forms the right end, and a right front floor frame 41 that extends along the right side sill 38.

  The front body 23 includes a left front side frame 25, a right front side frame 26, a front end of the left front side frame 25, a front bumper beam 44 attached to the front end of the right front side frame 26 via an extension 42, And the sub-frame 14 attached to the lower part of the right front side frame 26.

FIG. 3 is a perspective view of a subframe provided in the vehicle body front part structure of the present invention. This will be described with reference to FIG.
Specifically, the subframe 14 includes a left beam member 51 disposed and connected below the left front side frame 25 and a right beam member 52 disposed and connected below the right front side frame 26. A front beam member 55 connected to one end 53 of the left beam member 51 and one end 54 of the right beam member 52, a left rear end 25a of the left front side frame 25, and a right front side frame 26. And a rear beam member 58 connected to the other end portion 56 of the left beam member 51 connected to the right rear end portion 26a and the other end portion 57 of the right beam member 52.

Further, the subframe 14 has an energy absorption mechanism 15 joined to the inner side 62 of its corner 61.
The energy absorbing mechanism 15 is joined to the left front first bar member 66, which is an energy absorbing bar member joined to the left front corner 64 of the subframe 14 with a bolt 65, and to the right front corner 67 with a bolt 65. The right front first bar member 68 that is an energy absorbing bar member, the left rear second bar member 72 that is an energy absorbing bar member joined to the left rear corner portion 71 with a bolt 65, and the right rear corner portion 73, and a right rear second bar member 74 which is an energy absorbing bar member joined to a bolt 73 with a bolt 65.

The left front corner 64 is a predetermined range from the corner.
The right front corner portion 67, the left rear corner portion 71, and the right rear corner portion 73 are also within a predetermined range from the corner, like the left front corner portion 64.

The left front first bar member 66 forms a main body 76 in a rectangular tube shape, and a fastening end portion 77 is formed in a plate shape in connection with the main body 76.
The right front first bar member 68 is the same as the left front first bar member 66.
The left rear second bar member 72 and the right rear second bar member 74 are the same as the left front first bar member 66.
Note that the left front first bar member 66 to the right rear second bar member 74 are fastened with bolts 65, but do not use the bolts 65, and transmit force to the left beam member 51 and the right beam member 52. You may be made to be.

The left beam member 51 is formed with a first fastening portion 81 that fastens the fastening end portion 77 of the left front first bar member 66 at the center, and the fastening end portion 77 of the left rear second bar member 72 is fastened. A second fastening portion 82 is formed. And the left weak part 83 which is a weak part is formed in the one end part 53. FIG.
The left fragile portion 83 is in a form that is weaker than other parts (stress concentration is likely to occur), and, for example, the thickness is reduced or a groove is formed at the center between the first fastening portion 81 and the corner. Is.

The right beam member 52 has a third fastening portion 84 that fastens the fastening end portion 77 of the right front first bar member 68 at the center, and fastens the fastening end portion 77 of the right rear second bar member 74. A fourth fastening portion 85 is formed. And the right weak part 86 which is a weak part is formed in the one end part 54. FIG.
The right fragile portion 86 is in a form that is weaker than other parts (stress concentration is likely to occur), and, for example, a thin wall or a groove is formed in the center between the third fastening portion 84 and the corner. Is.

Next, the operation of the vehicle body front structure of the present invention will be described.
The vehicle body front structure 11 shown in FIGS. 2 and 3 has an energy absorbing bar member (a left front first bar member 66, a right front first bar member 68, an inner side 62 of a corner portion 61 of a rectangular frame-shaped subframe 14). Since the left rear second bar member 72 and the right rear second bar member 74) are attached, even if the engine 21 is arranged in the center of the subframe 14 and the engine 21 is supported by the subframe 14, the engine 21 and the energy The absorbing bar members (the left front first bar member 66, the right front first bar member 68, the left rear second bar member 72, and the right rear second bar member 74) do not interfere with each other. Accordingly, it is possible to ensure the degree of freedom of the engine layout of the subframe 14.

FIG. 4 is a view for explaining the load transmission mechanism of the vehicle body front structure according to the present invention.
When a load is applied to the front surface 88 of the vehicle 12 as indicated by an arrow b1, the vehicle body front structure 11 applies a load from the front bumper beam 44 to the left front side frame 25 and the right front side frame 26 via the extension 42 by the arrow b2. It is transmitted like. At that time, since the load transmitted to the left front side frame 25 and the right front side frame 26 is also transmitted to the subframe 14, it is transmitted to the left beam member 51 and the right beam member 52 as indicated by an arrow b3.

  The load transmitted to the subframe 14 is further transmitted to the left front first bar member 66 and the right front first bar member 68 as indicated by arrows b4 and b5, and is transmitted to the left beam member 51 and the right beam member 52 as indicated by arrow b6.

  In the left beam member 51, a load is transmitted from the center to the second left second bar member 72 as indicated by an arrow b7, and the rear beam member 58 is passed to the rear end 91 of the left beam member 51 as indicated by an arrow b8. It is transmitted as follows.

  In the right beam member 52, the load is transmitted from the center to the right rear second bar member 74 as indicated by an arrow c1, and the rear beam member 58 is passed to the rear end 92 of the right beam member 52 via the arrow c2 as indicated by the arrow c3. It is transmitted as follows. Therefore, the strength of the subframe 14 can be increased.

  Thus, the load applied to the front surface 88 is transmitted by the left front first bar member 66, the right front first bar member 68, the left rear second bar member 72, and the right rear second bar member 74, which are energy absorbing bar members. Therefore, energy can be absorbed by the vehicle body lower portion 94 of the vehicle 12, and energy can be absorbed more reliably.

  Along with the load (arrow b9) reaching the rear end 91 of the left beam member 51, the load transmitted to the left front side frame 25 is transmitted to the left front floor frame 37 and the left side sill 36 of the underbody 31.

  Along with the load (arrow c3) reaching the rear end 92 of the right beam member 52, the load transmitted to the right front side frame 26 is transmitted to the right front floor frame 41 and the right side sill 38.

  FIGS. 5A and 5B are conceptual diagrams for explaining the energy absorbing mechanism of the vehicle body front structure according to the present invention, and are views seen from below the vehicle 12. (A) shows the mechanism when the load is small, and (b) shows the mechanism when the load is large. Both (a) and (b) are conditions when a load is applied to a position offset to the left from the center of the front surface 88 of the vehicle 12. 1 to 3 will be used in combination.

The vehicle body front structure 11 shown in (a) is an energy absorbing bar member (a left front first bar member 66, a right front first bar member 68, a left front) in which a small load is formed on the subframe 14 when the load is small and offset. The force (stress) applied to the left beam member 51 of the sub-frame 14 is reduced by being transmitted to the rear second bar member 72 and the right rear second bar member 74), particularly the left front first bar member 66.
As a result, the deformation of the sub-frame 14 is suppressed, and only the front bumper beam 44 and the extension 42 in front of the sub-frame 14 are deformed. Therefore, when only the deformed front bumper beam 44 and the extension 42 are repaired, the repair is completed and the repair cost is reduced. Can be reduced.

When the vehicle body front part structure 11 shown in (b) is offset and has a large load, first, the left front corner part 64 of the subframe 14 is simultaneously deformed to absorb energy. Further, when the load is large, the left fragile portion 83 provided in the left beam member 51 is deformed or cracked, and the left beam member 51 bends as shown by an arrow d1, thereby continuously absorbing energy. it can.
As a result, it is possible to prevent the front body 23 from being deformed inside the vehicle compartment 28.

When the load is further increased, the compression load applied to the left front first bar member 66 increases, and further energy absorption (second stage energy absorption) is performed by deformation of the left front first bar member 66. it can.
At that time, the load is also transmitted to the right front first bar member 68, so that the right front first bar member 68 is also deformed to absorb energy (second stage energy absorption).

The remaining energy is transmitted through the rear end 91 of the left beam member 51 to the left front floor frame 37 and the left side sill 36 as indicated by an arrow d2.
Further, since the load is transmitted to the left rear second bar member 72 and the right rear second bar member 74, the strength of the subframe rear portion 95 of the subframe 14 can be improved, and the interior of the vehicle interior 28 of the front body 23 can be improved. It is possible to prevent deformation.

  In this behavior, a tensile load is generated on the right front side frame 26 to which no load is directly applied, as indicated by an arrow d3, but the right energy absorbing bar member (the right front first bar member 68, the right rear When the load is transmitted to the second bar member 74), the strength of the subframe 14 is improved, and the tensile force (stress) applied to the right front side frame 26 can be reduced. Therefore, deformation of the front body 23 toward the inside of the vehicle compartment 28 can be prevented more reliably.

  If the energy absorbing bar member (the left front first bar member 66, the right front first bar member 68, the left rear second bar member 72, the right rear second bar member 74) is a vehicle having a sub-frame, it has its own length. By adjusting the, it can be installed on an existing subframe.

  The energy absorbing bar member (the left front first bar member 66, the right front first bar member 68, the left rear second bar member 72, the right rear second bar member 74) is changed by changing the plate thickness, cross-sectional shape, and material itself. As a result, the strength of the subframe 14 can be easily controlled.

  The energy absorbing bar member (the left front first bar member 66, the right front first bar member 68, the left rear second bar member 72, the right rear second bar member 74) is changed by changing the plate thickness, cross-sectional shape, and material itself. Therefore, it is possible to change the shape of the subframe 14 such as the thickness and cross section of the subframe 14, and the energy absorbing bar members (the left front first bar member 66, the right front first bar member 68, The overall weight of the subframe 14 including the left rear second bar member 72 and the right rear second bar member 74) can be reduced.

  In addition, although the vehicle body front part structure of the present invention is adopted in the front part of the vehicle in the embodiment, it can be adopted also in the vehicle body rear part if a subframe is used in the rear part of the vehicle.

  The vehicle body front part structure of the present invention is suitable for a subframe employed in the front part of a vehicle.

It is a side view of the vehicle body front part structure of this invention. It is a perspective view of the vehicle body front part structure of this invention. It is a perspective view of the sub frame with which the vehicle body front part structure of the present invention is provided. It is a figure explaining the load transmission mechanism of the vehicle body front part structure of this invention. It is a conceptual diagram explaining the energy absorption mechanism of the vehicle body front part structure of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 11 ... Vehicle body front part structure, 14 ... Sub-frame, 21 ... Engine, 27 ... Front wheel, 51 ... Left beam member, 52 ... Right beam member, 53 ... One end part of left beam member, 54 ... One end part of right beam member, 61 ... Corner, 62 ... Inside, 64 ... Left front corner, 66 ... Energy absorbing bar member (left front first bar member), 67 ... Right front corner, 68 ... Right front first bar member, 71 ... Left rear corner, 72: left rear second bar member, 73: right rear corner portion, 74 ... right rear second bar member, 83 ... weak portion (left weak portion), 86 ... weak portion (right weak portion), 94 ... lower part of the vehicle body.

Claims (2)

In the vehicle body front part structure including a rectangular frame-shaped subframe that is attached to the lower part of the vehicle body to support the front wheels and the engine,
The vehicle body front structure, wherein the sub-frame has an energy absorbing bar member for absorbing energy applied from the outside inside each corner.   The sub-frame includes a left beam member positioned near the front wheel, a right beam member, a weakened portion formed at one end portion of the left beam member included in the corner portion, and one end portion of the right beam member. The vehicle body front part structure according to claim 1, further comprising a formed weak part.

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