JP4729021B2 - Body front structure - Google Patents

Description

  The present invention relates to a vehicle body front structure, and more particularly to a vehicle body front structure of a tunnel portion behind a transmission.

  Conventionally, a flat floor surface of a front part of a car body has been provided with a tunnel part having a long hole that bulges upward and extends in the front-rear direction of the car body, and a transmission cover attached to the periphery of the long hole. (For example, refer to Patent Document 1).

FIG. 6 is a perspective view of a main part showing the structure of a conventional automobile tunnel.
As shown in FIG. 6, each flange portion 210 of the transmission cover 200 has a lateral dimension of a portion extending from a convex portion 220 formed in the tunnel portion 100 to a through hole 230 for installing a shift lever. It is formed larger than the horizontal dimension. Therefore, the transmission cover 200 is set so that the rigidity in the vicinity of the ridge portion where deformation starts to occur in the tunnel portion 100 behind the convex portion 220 is increased, and the tunnel portion 100 behind the convex portion 220 is arranged in the front-rear direction. It prevents deformation when it receives a collision load (in the direction of arrow A).

  As a result, when the automobile has a severe frontal collision, the deformation of the tunnel portion 100 behind the convex portion 220 is delayed in the transmission cover 200, so that the tunnel portion 100 is sequentially deformed from the front toward the rear (arrow A direction). It is possible to absorb more collision energy.

  FIG. 7 is a diagram showing the installation relationship between a tunnel portion and a transmission of a conventional automobile, (a) is a schematic front view of the tunnel portion, and (b) is moved in collision with the transmission installation position with respect to the tunnel portion. It is the schematic which shows the position of a transmission. FIG. 8 is a schematic view showing the installation relationship between the tunnel portion and the transmission of another conventional automobile and the position of the transmission moved in collision.

  When the automobile has a severe collision, for example, as shown in phantom lines in FIG. 7B and FIG. 8, the transmission 300 installed beside the engine may be pushed backward by the opponent vehicle. . As a method for preventing the tunnel members 100A and 100B and the cross members 400A and 400B connected to the dashboard panel 500 from hitting the retreating transmission 300, for example, the cross member 400A shown in FIG. There are two methods, a method of installing the device in a shifted manner and a method of installing the cross member 400B shown in FIG. 8 in a retracted position.

  As shown in FIG. 7B, in the method in which the installation position of the cross member 400A extending in the vehicle width direction of the vehicle body is shifted upward by the height H1 from the transmission 300, the retreated transmission 300A contacts the tunnel portion 100A. Can be installed without touching.

  Further, as shown in FIG. 8, in the method in which the cross member 400B is installed at a position having a further rearward margin with respect to the retraction amount L1 of the transmission 300B at the time of a collision, the cross member 400B is not brought into contact with the transmission 300B. Can be installed.

Japanese Patent No. 3042080 (paragraphs 0009 and 0010, FIGS. 1 and 6)

  In the vehicle floor structure disclosed in Patent Document 1, as shown in FIG. 6, when an impact force A is applied to the rear of the tunnel portion 100 at the time of a severe collision, particularly at the front end of the tunnel portion 100. A relatively large load is applied to the region B and the region C behind the convex portion 220 to facilitate deformation. In this case, since the collision energy is absorbed by the deformation of the tunnel portion 100 triggered by the deformation of the regions B and C, it is necessary to secure the regions B and C. The problem is that space is reduced.

  Further, in the method shown in FIGS. 7A and 7B, when the height H1 of the installation position of the cross member 400A is increased, the tunnel portion 100A is moved along with the increase of the installation position of the cross member 400A. Since the height H2 increases and becomes a large shape, there is a problem that the thickness of the member forming the tunnel portion 100A must be increased in order to give the tunnel portion 100A rigidity.

  Further, in the method shown in FIG. 8, when the installation position of the cross member 400B is moved backward with respect to the reverse movement of the transmission 300 at the time of a collision, it is necessary to move the occupant's boarding position backward as well. As the installation position of the cross member 400B is changed, other peripheral members such as the dashboard panel 500 must be moved or the shape thereof must be changed. For this reason, there has been a problem that a large restriction or the like occurs in the design or packaging of the vehicle body.

  The present invention has been developed to solve the above-described problems, and it is an object of the present invention to provide a vehicle body front structure capable of absorbing collision energy at the time of vehicle collision without impairing the degree of freedom of vehicle body design. To do.

In order to solve the above problem, the vehicle body front structure according to claim 1 is provided with a crushable zone at a front end of a tunnel portion provided on a floor portion of a passenger compartment, and a vehicle length in front of the crushable zone. the directionally extension on, a vehicle body front structure transmission is installed, before SL at both ends in the vehicle width direction of the crushable zone, front and rear of the vehicle body are arranged at a distance from the tunnel portion A front side frame extending in the direction, a cross member adjacent in the vehicle width direction of the crushable zone, and a tunnel extending in the vehicle longitudinal direction behind the end of the tunnel portion in the vehicle width direction and the frame, are provided, the front side frame and said tunnel frame, the linked by the cross member, the crushable zone, Tsuyoshi installed in the cabin side A metal consisting of plate slab high, is installed in the engine room side, with is provided so as to form a hollow closed cross-section on the lower surface of the thick plate of the front end portion of the tunnel portion, than the thickness material The transmission is formed by joining a thin plate made of a metal plate material having low rigidity, and the thin plate is retracted by a crash stroke of the engine room and the front side frame in a severe frontal collision. It is installed in the position which the upper end part of contact | abuts .

According to the invention described in claim 1, in the crushable zone provided at the front end of the tunnel portion, the plate material installed on the engine room side is set to be lower in rigidity than the plate material installed on the vehicle compartment side. Thus, for example, when a severe frontal collision that causes the engine room to be crushed, a power train such as a transmission arranged from the engine room toward the tunnel part is pushed backward toward the vehicle body, The transmission hits the crushable zone. At the time of such a collision, in the crushable zone, a crash stroke (the amount of deformation in the collision direction at the time of collision) is ensured so that a plate material with low rigidity on the engine room side is crushed by the transmission to absorb the collision energy. Therefore, it is possible to suppress the tunnel portion from being deformed at the time of collision.
Furthermore, according to the invention described in claim 1, the front side frame disposed at a distance from the tunnel portion and extending in the front-rear direction of the vehicle body at both ends in the vehicle width direction of the crushable zone, A tunnel frame extending in the front-rear direction of the vehicle body is provided at an end of the tunnel portion in the vehicle width direction, and the front side frame and the tunnel frame are connected by a cross member. A tunnel frame that holds the end is firmly connected to the front side frame and held.
When the transmission hits the front end of the tunnel part in a severe collision, the cross member is buffered by hitting the crushable zone, and the vehicle compartment side of the tunnel part is protected by a rigid plate material, and the vehicle width of the tunnel part is Since the end portion in the direction is held by the tunnel frame, the tunnel portion can be protected from impact. As a result, the installation position of the cross member can be arranged at the height of the lower position of the tunnel portion, and the installation position of the cross member, the front end position of the tunnel portion, and the installation position of the dashboard portion can be set. Since it can be configured close to the engine room side (front side), the vehicle compartment space can be widened.
Since the deformation of the tunnel part at the time of a vehicle collision can be suppressed by a crushable zone or the like, it is possible to improve the degree of freedom of installation of the cross member and to arrange it at an effective position that can ensure the rigidity of the vehicle body, It is possible to reduce the weight of the vehicle body by forming the tunnel frame from a light metal such as an aluminum alloy or a lightweight material.
The vehicle can install the cross member at the lower position of the tunnel portion, so that the installation position of the skeleton such as the front side frame and the tunnel frame connected to the cross member is installed at a low position. Will be able to. Along with this, it is possible to lower the vehicle floor and lower the vehicle height to improve the degree of freedom in designing the vehicle body, and also to lower the center of gravity position of the vehicle body, so that the exercise performance can be improved. it can.

The vehicle body front structure according to claim 2 is the vehicle body front structure according to claim 1, wherein the dashboard lower installed along the vehicle width direction below the dashboard upper has a U-shaped cross section. It is characterized by being joined so as to close the opening of the cross member made of the above metal material .

According to the invention described in claim 2, since the dashboard lower is joined so as to close the opening of the cross member made of a metal material having a U-shaped cross section, the rigidity is improved.

The vehicle body front structure according to claim 3 is the vehicle body front structure according to claim 1 or 2, wherein the thick plate is formed of a steel plate, and the thin plate is a thick plate made of the steel plate. It is characterized by being formed of a plate material made of an aluminum alloy having a lower rigidity .

According to the invention described in claim 3, the crushable zone may be formed by forming a thick plate from a steel plate having a high rigidity and forming a thin plate from a plate material made of an aluminum alloy having a lower rigidity than a plate material having a high rigidity.

  According to the vehicle body front part structure according to the present invention, the vehicle body front part structure can improve the degree of freedom of the vehicle body design and can absorb the collision energy at the time of vehicle collision by the crushable zone provided at the front end of the tunnel part. Can be provided.

The best mode for carrying out the present invention will be described in detail with reference to the drawings. Hereinafter, the description will be made assuming that the traveling direction of the vehicle is “front”, the backward direction is “rear”, and the vehicle width direction is “left” and “right”.
FIG. 1 is a main part schematic diagram showing a vehicle body front part structure according to an embodiment of the present invention. FIG. 2 is a schematic plan view showing an installation state of the front side frame, the cross member, and the tunnel frame in the vehicle body front structure according to the embodiment of the present invention. FIG. 3 is a view showing the vehicle body front part structure according to the embodiment of the present invention, and is a perspective view showing a state when the tunnel part is looked up from below. 4A and 4B are views showing an installation state of the cross member in the vehicle body front part structure according to the embodiment of the present invention. FIG. 4A is an enlarged cross-sectional view taken along the line XX of FIG. 3, and FIG. FIG. FIG. 5 is a diagram showing a vehicle body front part structure according to the embodiment of the present invention, and is a perspective view showing an installation state of a thick plate in a tunnel part.

≪Vehicle configuration≫
First, a vehicle 1 to which a vehicle body front structure according to an embodiment of the present invention is applied will be described.
As shown in FIG. 1, a vehicle 1 is an automobile having an engine room ER at the front portion of a vehicle body, and a vehicle compartment (guest room) R disposed in the engine room ER with a partition wall 3 interposed therebetween. FR (front engine / rear drive) and four-wheel drive passenger cars. As shown in FIG. 2, a pair of front side frames 4, 4, cross members 5, 5, tunnel frames 6, 6 forming a skeleton of the vehicle body are provided below a dashboard portion (not shown) of the vehicle 1. The floor frames 7, 7 and side sills (not shown) are installed substantially symmetrically.
The vehicle 1 has a power unit 2 (see FIG. 2) in the engine room ER, and the type and type of the vehicle 1 are not particularly limited as long as the vehicle 1 includes a tunnel portion 81 to be described later on the floor surface portion of the passenger compartment R. Hereinafter, the present invention will be described by taking the case of an FR passenger car as an example.

≪Engine room configuration≫
As shown in FIG. 1, a power unit 2 is installed in the center of the engine room ER, a bumper (not shown) is disposed on the front side of the engine room ER, and a partition wall on the rear side of the engine room ER. 3 and a dashboard portion (not shown) are installed, and a pair of front side frames 4 and 4 (see FIG. 2) disposed in the front-rear direction of the vehicle body are installed on the left and right below the engine room ER. Yes. The engine room ER and the front side frames 4 and 4 (see FIG. 2) have a structure having a crash stroke that is crushed and deformed to absorb the collision energy when the vehicle 1 has a severe frontal collision.

≪Power unit configuration≫
As shown in FIG. 1, the power unit 2 includes, for example, an engine 21 and a transmission 22 installed in the vicinity of the engine 21. The power unit 2 includes a mounting member (not shown) and the front side frames 4 and 4. It is installed in the approximate center of the engine room ER with a subframe interposed.
The power unit 2 only needs to have a power train described later, and a clutch may be installed between the engine 21 and the transmission 22.

The engine 21 is a power source of the vehicle 1 and includes, for example, a gasoline engine, a diesel engine, an electric motor, a hybrid engine, or the like.
The transmission 22 is a power transmission device that transmits the output of the engine 21 to drive wheels via a power train such as a propeller shaft or a universal joint (not shown), and may be an automatic transmission or a manual transmission. The transmission 22 is disposed from the engine room ER toward the tunnel portion 81 of the floor panel 8, and is installed at a height at which the upper end portion 22a moves backward upon a severe collision and hits a crushable zone 84 described later. Yes.

≪Configuration of front side frame≫
As shown in FIG. 2, the front side frames 4 and 4 are a pair of members that form a skeleton of the vehicle body, and are formed of, for example, a steel square pipe member having a rigid cross-section and a square shape. The front side frames 4 and 4 are arranged from the left and right front end portions of the engine room ER toward the rear along the vehicle body, and the rear end portions are welded so as to be continuous with the cross members 5 and 5 and the floor frames 7 and 7. Further, the rear ends of the cross members 5 and 5 are welded to the tunnel frames 6 and 6, and the rear ends of the floor frames 7 and 7 are welded to left and right side sills (not shown). Forming part of the framework of the car body. As described above, the rear end portions of the front side frames 4 and 4 have the cross members 5 and 5 and the floor frames 7 and 7 installed in a substantially Y shape so that the direction of the load from the front is on the rear side. Bifurcated into two branches.

≪Cross member configuration≫
As shown in FIG. 2, the cross members 5 and 5 are skeleton members arranged substantially in the left-right direction with respect to the vehicle body. For example, a cross-shaped U-shaped grooved steel having rigidity (FIG. 4A). , (B)) is formed by bending. The cross members 5, 5 are front side frames 4, 4 extending in the front-rear direction of the vehicle body at positions separated from the front end portions in both the left and right directions of the tunnel portion 81, and the front-rear direction of the vehicle body at the left and right ends of the tunnel portion 81. This is a member that is interposed between the tunnel frames 6 and 6 that extend to each other and connects the two. The cross members 5, 5 are arranged in a state of expanding obliquely forward from the front ends of the tunnel frames 6, 6 toward the rear ends of the front side frames 4, 4, and are installed below the dashboard lower 31. Has been. In other words, the cross members 5 and 5 are side sills (not shown) arranged at the left and right ends of the vehicle body from the front ends of the ladder-shaped tunnel frames 6 and 6 through the rear end portions of the front side frames 4 and 4. It is installed towards.

A flange portion as a welding allowance is formed at the front end portions of the cross members 5 and 5, and the flange portions are welded to the inner rear end portions of the front side frames 4 and 4. A flange portion as a welding allowance is formed at the left and right end portions of the central portion of the cross members 5 and 5, and the flange portion is welded to the lower end portion of the dashboard lower 31. A flange portion as a welding allowance is formed at the rear end portions of the cross members 5 and 5, and the flange portions are welded to the front end portions of the tunnel frames 6 and 6.
Center-side halves 5 a and 5 a formed on the rear side of the left and right cross members 5 and 5 are arranged at the left and right end portions of the front end portion of the tunnel portion 81 to form the skeleton of the tunnel portion 81. A thin plate 83 (see FIG. 1) and a thick plate 82 forming a crushable zone 84 are installed at the front end portion of the tunnel portion 81 between the central half portions 5a and 5a.

  As shown in FIG. 2, the cross members 5, 5 are substantially the same as the member first half 31 a of the dashboard lower 31 in plan view due to the crushable zone 84 being interposed between the left and right cross members 5, 5. The cross members 5 and 5 can be arranged at the same height as the lower end portion of the tunnel portion 81 as shown in FIG. It is possible. The cross members 5 and 5 are members also called dash lower cross members.

<< Configuration of tunnel frame >>
As shown in FIG. 2, the tunnel frames 6 and 6 are made of a pair of left and right metal members extending in the vehicle front-rear direction at the left and right end portions of the tunnel portion 81 installed at the center of the floor portion of the passenger compartment R. The skeleton member is formed in a hollow shape by a light metal such as an aluminum extrusion material. The two tunnel frames 6 and 6 have a ladder frame structure formed in a ladder shape by the erection member 61, and are strong enough to allow a hand brake, a shift lever, etc. to be installed on the console part formed by the tunnel part 81. Has been improved. Since the left and right tunnel frames 6 and 6 are firmly connected in this way, the left and right cross members 5 and 5 installed at the tip can also be firmly connected and held.
As shown in FIG. 4B, the tunnel frames 6 and 6 (only one of them is shown) have the front ends of the tunnel frames 6 and 6 being cross members 5 and 5 and a dashboard portion (not shown) of the vehicle 1. It is fixed in a state of being sandwiched and sandwiched by a dashboard lower 31 installed in the lower part.

≪Configuration of floor frame≫
As shown in FIGS. 2, 3, and 5, the floor frames 7 and 7 are skeleton members for holding the floor panel 8, and are respectively installed on the lower surfaces of the left and right floor panels 8. The front ends of the floor frames 7, 7 are welded to the rear ends of the front side frames 4, 4, and the rear ends are welded to the side surfaces of the left and right side sills (not shown) on the passenger compartment side.

<< Configuration of bulkhead >>
As shown in FIGS. 1, 4 and 5, the partition wall 3 is a member for partitioning the engine room ER and the vehicle compartment R, and is formed by bending a metal flat plate member such as a relatively thin steel plate. Has been. The partition wall 3 is composed of a dashboard upper (not shown) extending in the left-right direction, a dashboard lower 31 installed along the vehicle width direction below the dashboard upper, and the like.

As shown in FIGS. 2 and 5, the dashboard lower 31 is a plate member that forms the lower part of the dashboard portion, and is a member that partitions the engine room ER and the vehicle compartment R installed vertically in the vehicle width direction. The outer half is joined to the central half 51a of the cross member 5 and the floor panels 8 and 8 by being bent from the lower end of the front half 31a of the member toward the floor side of the passenger compartment R. Member latter half part 31b.
As shown in FIG. 3 and FIG. 4 (a), the member front half part 31a is installed so as to close and join the rear end openings of the cross members 5 and 5 made of a metal material having a U-shaped cross section. The engine room ER and the vehicle compartment R are interposed.
As shown in FIG. 5, the member rear half part 31b is fixed by spot welding or the like by bending the lower end part of the member front half part 31a into a substantially L shape so as to overlap the floor panel 8 and the tunnel frames 6 and 6. .

≪Configuration of floor panel≫
As shown in FIG. 1, the floor panel 8 is a metal flat plate member that forms the floor surface of the front seat of the passenger compartment R, and has a tunnel portion 81 at the center portion along the vehicle front-rear direction. At the front end of the tunnel portion 81 of the floor panel 8, there are a thick plate 82 made of a plate material having a high rigidity on the vehicle compartment R side, and a thin plate 83 made of a plate material having a lower rigidity than the thick plate (a plate material having a high rigidity) 82 on the engine room ER side. The crushable zone 84 comprised by these is provided.

  Even if the floor panel 8 is laid with a single flat plate on the entire floor surface of the front seat of the passenger compartment R including the tunnel portion 81, the floor surface on the driver seat side and the floor on the passenger seat side are provided. The surface and the tunnel portion 81 may be either three pieces in which the respective flat plate members are connected and laid. That is, a flat plate member such as a transmission cover other than the floor panel 8 may be installed in the tunnel portion 81.

<Configuration of tunnel part>
The tunnel portion 81 is a center portion of the floor portion having strength and rigidity that is called a so-called floor tunnel. The tunnel portion 81 is opened in accordance with a power train (not shown) or the like disposed below the tunnel portion 81, and a thin plate 83 whose thickness is formed in a U-shape (tunnel shape) having a substantially downward cross section when viewed from the front is described later. It is formed by a thicker plate 82, the tunnel frames 6 and 6, and a resin material (not shown) that covers the tunnel R side of the tunnel portion 81. The tunnel part 81 is formed along the vehicle body from the rear part of the transmission 22 installed in the engine room ER toward the rear seat side central part of the passenger compartment R. In the tunnel portion 81, for example, a power train such as a propeller shaft (not shown), piping, wires, and the like are arranged.

<Structure of thick plate>
The thick plate 82 is made of a metal plate such as a steel plate or an aluminum alloy plate, and is fixed to the tunnel frames 6 and 6 and the dashboard lower 31 installed at the left and right ends of the tunnel portion 81 by spot welding or industrial adhesive. ing.

<Structure of thin plate>
The thin plate 83 is made of a metal plate such as a thin steel plate or an aluminum alloy plate as compared with the thick plate 82, and is made of a plate material whose rigidity is set lower than that of the thick plate 82. The thin plate 83 is joined to the thick plate 82 by spot welding or the like so that a crushable zone 84 having a hollow closed cross section is formed on the lower surface of the thick plate 82 at the front end of the tunnel portion 81.

<Configuration of crushable zone>
The crashable zone 84 is installed at a position where the upper end portion 22a of the transmission 22 that has moved backward by the crash stroke of the engine room ER and the front side frames 4 and 4 abuts during a severe frontal collision to absorb the collision energy. In order to prevent the tunnel portion 81 from being deformed, it is installed. That is, the transmission 22 is installed on the extension in the vehicle length direction in front of the crushable zone 84.
Front side frames 4, 4 that are arranged at a distance from the tunnel portion 81 and extend in the front-rear direction of the vehicle body at both ends in the left-right direction of the crashable zone, and the left-right ends of the tunnel portion 81 Tunnel frames 6 and 6 extending in the front-rear direction of the vehicle body are provided. The front side frames 4 and 4 and the tunnel frames 6 and 6 are connected by cross members 5 and 5 (see FIGS. 2, 3 and 5). The crushable zone 84 has a differential thickness structure formed by joining a thin plate 83 installed on the engine room ER side to a thick plate 82 installed on the vehicle compartment R side.

≪Operation of the front body structure≫
Next, referring to FIG. 1 mainly with reference to FIGS. 2 to 5, the operation of the vehicle body front structure according to the embodiment of the present invention is an example in which the vehicle 1 has a severe frontal collision (frontal collision) with another vehicle. Will be described.
As shown in FIG. 1, when the vehicle 1 travels, for example, when a severe frontal collision with another vehicle occurs, a bumper (not shown) installed at the front of the vehicle 1 is moved rearward by the other vehicle. When pressed, the front end portions of the front side frames 4 and 4 are pressed via a bumper beam (not shown). Since the front side frames 4 and 4 are crushed and deformed together with the engine room ER by another vehicle, the collision energy can be appropriately absorbed by the crash stroke.

  When the front side frames 4 and 4 and the engine room ER are crushed by another vehicle, the radiator, the engine 21, the transmission 22 and the like installed in the engine room ER are pressed by the other vehicle, and the rear side of the arrow D ( Move in the direction of the passenger compartment R). Then, the transmission 22 moves rearward as indicated by a virtual line in FIG. 1, and the upper end portion 22 a crushes the thin plate 83 of the crushable zone 84 installed at the front end portion of the tunnel portion 81. As a result, the crash energy is absorbed by the crushable zone 84 and the movement of the transmission 22 is stopped.

  In the crushable zone 84, the thick plate 82 and the thin plate 83 form a closed cross section having a differential thickness structure, so that the thin plate 83 has appropriate rigidity and buffering properties. For this reason, it is possible to absorb the collision energy by the crash stroke in which the thin plate 83 is crushed in the transmission 22 that has moved due to a severe collision, and the transmission 22 can be received only by the thin plate 83. For this reason, the transmission 22 retreating by the thin plate 83 of the crushable zone 84 is locally received, and the thick plate 82 hardly deforms. Therefore, the tunnel portion 81 installed around the thick plate 82 and the periphery of the tunnel portion 81 The contact of the transmission 22 with the member is suppressed, and it is possible to prevent the tunnel portion 81 and its surrounding members from being deformed or destroyed by the collision load at the time of collision.

  As a result, the cross members 5 and 5 adjacent to the crushable zone 84 in the left and right outer direction are not in contact with the transmission 22 even if the transmission 22 is retracted due to a severe collision. Installation in the vehicle, a configuration close to the engine room ER on the front side of the vehicle body, and a configuration in which the engine 21 and the transmission 22 are close to the vehicle body center side (vehicle compartment R side) compared to the conventional case. Is possible. As a result, the floor of the vehicle body and the height of the vehicle can be reduced, the position of the center of gravity of the vehicle body can be changed as appropriate to improve the motion performance of the vehicle 1, and the degree of freedom in the design of the vehicle body is improved. be able to.

Further, by installing the cross members 5 and 5 and the partition 3 installed on the cross members 5 and 5 close to the front side (engine room ER side), the vehicle interior R space can be expanded.
Thus, by providing the crushable zone 84 at the front end of the tunnel portion 81, the retracted transmission 22 can be received locally, so that the cross members 5 and 5 provided on the peripheral portion can be connected to the coupling efficiency and load. It can be arranged at a position with good transmission efficiency.

  Moreover, since the tunnel part 81 has the crushable zone 84, since it has rigidity and intensity | strength, while making it possible to form the tunnel frames 6 and 6 with light metals, such as an aluminum extrusion material, crushable zone Since 84 is formed of a light thin plate 83, the weight of the vehicle body can be reduced. Since the tunnel frames 6 and 6 are welded in a state where the front ends are surrounded and sandwiched between the cross members 5 and 5 and the dashboard lower 31, the tunnel frames 6 and 6 can be firmly held on the vehicle body to improve the rigidity.

[Modification]
The present invention is not limited to the above-described embodiment, and various modifications and changes can be made within the scope of the technical idea. The present invention extends to these modifications and changes. Of course.

In the embodiment, the case where the crushable zone 84 is formed by the thick plate 82 and the thin plate 83 has been described, but the crushable zone 84 is not limited to this. For example, in the crushable zone 84, the thick plate 82 is formed of a plate material such as a strong steel plate, and the thin plate 83 is formed of a light alloy such as an aluminum alloy having a lower rigidity than a high rigidity plate material or a plate material made of a resin material. You may have done. That is, you may form with a board material with high rigidity and a board with low rigidity by the dissimilar material from which rigidity differs.
Further, a cushioning material such as a foam material or a soft resin material may be provided in the crushable zone 84 formed in a hollow shape by the thick plate 82 and the thin plate 83.

  In addition, the joining method of each member is not limited to the aspect demonstrated by above-mentioned embodiment, What is necessary is just to select suitably from well-known joining methods, such as welding, adhesion | attachment, and mechanical joining. Not too long.

It is a principal part schematic diagram which shows the vehicle body front part structure which concerns on embodiment of this invention. FIG. 3 is a schematic plan view showing an installation state of a front side frame, a cross member, and a tunnel frame in the vehicle body front part structure according to the embodiment of the present invention. It is a figure which shows the vehicle body front part structure which concerns on embodiment of this invention, and is a perspective view which shows a state when a tunnel part is looked up from the downward direction. It is a figure which shows the installation state of the cross member in the vehicle body front part structure which concerns on embodiment of this invention, (a) is the XX expanded sectional view of FIG. 3, (b) is the YY expanded of FIG. It is sectional drawing. It is a figure which shows the vehicle body front part structure which concerns on embodiment of this invention, and is a perspective view which shows the installation state of the thick board in a tunnel part. It is a principal part perspective view which shows the structure of the tunnel part of the conventional motor vehicle. It is a figure which shows the installation relationship of the tunnel part and transmission of the conventional motor vehicle, (a) is a schematic front view of a tunnel part, (b) is the position of the transmission which collided with the installation position of the transmission with respect to the tunnel part, and FIG. It is the schematic which shows the installation relationship of the tunnel part and transmission of another conventional motor vehicle, and the position of the transmission which collided and moved.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Vehicle 2 Power unit 3 Bulkhead 4 Front side frame 5 Cross member 6 Tunnel frame 8 Floor panel 22 Transmission 31 Dashboard lower 81 Tunnel part 82 Thick board (plate material installed in the passenger compartment side)
83 Thin plate (plate material installed on the engine room side)
84 Crashable zone ER Engine room R Car compartment

Claims (3)

A crushable zone is provided at the front end of the tunnel provided on the floor of the passenger compartment .
On the extension in the vehicle length direction in front of the crushable zone, a vehicle body front structure in which a transmission is installed ,
Front side frames arranged at a distance from the tunnel portion and extending in the front-rear direction of the vehicle body at both ends in the vehicle width direction of the crushable zone;
A cross member adjacent to the crushable zone in the vehicle width direction;
A tunnel frame extending in the front-rear direction of the vehicle body is provided behind the end of the tunnel portion in the vehicle width direction, and
The front side frame and the tunnel frame are connected by the cross member,
The crushable zone is a thick plate made of a highly rigid metal plate installed on the passenger compartment side;
It is installed in the engine room side, with is provided so as to form a hollow closed cross-section on the lower surface of the thick plate of the front end portion of the tunnel portion, consisting of the set metal plate lower rigidity than the thickness material Formed by joining thin plates,
The vehicle body front structure according to claim 1, wherein the thin plate is installed at a position where the upper end portion of the transmission that has moved backward by a crash stroke of the engine room and the front side frame comes into contact in a severe frontal collision . A dashboard lower installed along the vehicle width direction below the dashboard upper is joined so as to close the opening of the cross member made of a metal material having a U-shaped cross section. The vehicle body front part structure according to claim 1. The thick plate is formed of a steel plate,
The vehicle body front structure according to claim 1 or 2, wherein the thin plate is formed of a plate material made of an aluminum alloy having lower rigidity than the thick plate made of the steel plate .

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