JP5187105B2 - Body front structure - Google Patents

Description

  The present invention relates to a vehicle body front portion structure, and more particularly to a vehicle body front structure that can improve safety when a vehicle central portion in the vehicle width direction collides with a pole-shaped obstacle.

  The front part of the vehicle body generally connects the left and right end parts of the bumper reinforcement extending in the vehicle width direction at the front end of the vehicle body to the front ends of the pair of left and right front side frames, more specifically via a crash can. Structure is adopted. That is, as the vehicle body front structure, a structure in which the left and right front side frames function as a main shock absorbing member at the time of a frontal collision is adopted.

  The impact safety performance test for frontal collisions is conducted in two ways. The first aspect is a full wrap frontal collision and the second aspect is an offset frontal collision. In the full-wrap frontal collision test, the vehicle is made to collide with a concrete barrier at a predetermined speed. In the offset frontal collision test, one side of the vehicle (overlap ratio 40%) is subjected to frontal collision with a honeycomb-shaped barrier.

  In Patent Document 1, a bumper reinforcement is attached to the front ends of the left and right front side frames via a crash can, and a so-called perimeter frame having a substantially rectangular frame shape as a sub-frame is disposed below the front side frame as a subframe. A vehicle body front structure is disclosed, and it is proposed to absorb collision energy with a crash can when it collides with the pole at low speed in frontal collision with the pole at low speed.

  Patent Document 2 proposes an invention that absorbs collision energy by buckling of the front end portion of the front side frame at the initial stage of collision in a full-wrap frontal collision and offset frontal collision and relaxes the deceleration of the occupant in the late stage of the collision. . Specifically, in Patent Document 2, a pipe extending in the vehicle width direction is provided between the rear end portions of the left and right front side frames having a rectangular closed cross-sectional structure, and the left and right ends of the pipe are arranged on the inner side of the front side frame. A structure that connects to the side is proposed. According to this invention, when the power plant retreats due to a collision, the retreating power plant causes the connecting pipe extending in the vehicle width direction to bend backward, and the rear end portions of the left and right front side frames are bent by the bending of the connecting pipe. By bending the vehicle inward in the vehicle width direction, the deceleration of the occupant in the latter half of the collision can be mitigated.

  Patent Document 3 discloses a collision in a full-wrap frontal collision and an offset frontal collision by connecting the left and right front side frames and a sub-frame (perimeter frame) having a substantially rectangular frame shape arranged in plan view below the left and right front side frames. Proposals are being made to improve the impact strength in the early and mid-collisions and reduce the deceleration in the late-collision period.

JP 2006-175988 A JP 2002-120752 A JP 2004-26888 A

  Incidentally, as described above, typical examples of the frontal collision include a full lap collision and an offset collision, but there are, of course, various aspects in an actual frontal collision accident. One of them is the case of crashing into a power pole or road sign post planted on the side of the road. When a frontal collision occurs on the side of the vehicle against this pole-shaped obstacle, the impact can be absorbed by one of the front side frames as in the offset frontal collision test described above. However, if the center of the vehicle in the vehicle width direction collides with a pole-shaped obstacle, the bumper reinforcement is generally not designed to have the strength to catch it. As a result, the left and right front side frames do not function, and there is a risk that large damage will occur.

  An object of the present invention is to absorb the collision energy using a front side frame when a central portion in the vehicle width direction collides with an obstacle such as a pole that is not widened in the vehicle width direction. The object is to provide a front body structure.

According to the present invention, the above technical problem is
Left and right front side frames extending in the longitudinal direction of the vehicle body and having a closed cross-sectional structure in an engine room where a power plant including an engine is disposed;
In the vehicle body front part structure, which is disposed below the left and right front side frames and has a substantially rectangular frame-shaped subframe in plan view,
The front side frame buckles with respect to the collision load from the front and absorbs the collision energy, and is located behind and bends with respect to the collision load from the front to absorb the collision energy. It has a collision energy absorption structure with a bending area,
The sub-frame is a front connecting portion that connects left and right side portions extending in the front-rear direction along the left and right front side frames and a front end of the left and right side portions, A front connection portion extending in the vehicle width direction at a lower position of the front end portion of each buckling region,
The vehicle body front structure is
Further comprising a collision load transmission member extending toward the left and right front side frame from the front end portion of the side portions of the left and right of the sub-frame,
The collision load transmitting member has an axis extending obliquely upward and rearward,
The upper ends of the left and right collision load transmitting members respectively correspond to the rear end of the buckling region of the left and right front side frames, the boundary between the buckling region and the bending region, or the front end of the bending region. This is achieved by providing a vehicle body front structure characterized in that it is connected to the lower surface of the vehicle body.

  According to the present invention, when the front portion of the vehicle collides with an obstacle that does not have a large width in the vehicle width direction such as a pole in a frontal collision, and the collision load is applied to the subframe. Part of the collision load input to the subframe is input to the front side frame via the collision load transmission member, and can be absorbed by the collision energy absorption function of the front side frame. In other words, bumper reinforcement is usually arranged at the front ends of the left and right front side frames, but this bumper reinforcement is used when the pole collides with the center in the longitudinal direction. Usually, it does not have enough rigidity to resist, so there is a risk that the pole may enter the engine room. On the other hand, the collision load input to the subframe is fronted by the collision load transmission member. By inputting to the side frame, the collision energy at the initial stage of the collision can be absorbed using the collision energy absorption function of the front side frame. In other words, if it is attempted to cope with a pole collision by means of bumper reinforcement, it is necessary to increase the rigidity of the bumper reinforcement, which increases the weight of the vehicle body.

  According to the present invention, since the axis of the collision load transmitting member extends obliquely rearward and upward from the subframe, the collision load input to the subframe can be smoothly input to the front side frame.

According to a preferred embodiment of the present invention,
The collision load transmission member includes a first member on the sub-frame side and a second member on the front side frame side, and both the first and second members have a closed cross-sectional structure, The member has an axis extending obliquely upward and rearward from the front end portion of the subframe, and the second member has an axis extending obliquely downward and forward from the lower surface of the front side frame, The upper end of the first member and the lower end of the second member are opposed to each other. According to this embodiment, in the vehicle body assembly, the upper end of the first member on the subframe side and the lower end of the second member on the front side frame side are brought into contact with each other and connected to each other, thereby transmitting a collision load. The member can be made easily.

According to a preferred embodiment of the present invention,
The power plant is mounted on the front side frame via a mount member, and the mount member is disposed at a position offset backward from a position where the collision load transmission member merges with the front side frame. . According to this embodiment, the collision load can be absorbed by the front end portion of the front side frame at a stage before the timing at which the pole collides with the power plant and the power plant moves backward.

  Other objects and advantages of the present invention will become apparent from the following detailed description of the preferred embodiments.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a vehicle body front part structure of the embodiment as viewed from the side, and FIG. 2 is a bottom view of the vehicle body front structure of the embodiment as viewed from below. First, referring to FIG. 1, reference numeral 10 indicates a dash panel, and a vehicle compartment 12 and an engine room 14 are partitioned by the dash panel 10. The vehicle compartment 12 has a floor surface formed by a floor panel 16 having a front end connected to the lower end of the dash panel 10, and the vehicle compartment 12 is provided with an instrument panel 18, a brake pedal 20, an accelerator pedal, and the like. Yes. Reference numeral 22 is a front window.

  In the lower region of the engine room 14, left and right front side frames 24 extending over the entire region of the engine room 14 in the longitudinal direction of the vehicle body are disposed, and the front side frame 24 has a rectangular closed cross-sectional structure. ing. As is known, a bumper reinforcement 26 extending in the vehicle width direction is connected to the front ends of the left and right front side frames 24 via a crash can 28. A perimeter frame as a sub-frame 30 positioned below the front side frame 24 is further disposed in a lower region of the engine room 14. Reference numeral 32 is a front wheel.

  The perimeter frame 30 is positioned at the rear end of the engine room 14 and extends in the vehicle width direction, and the side portion 30b extends forward along the front side frame 24 from both ends of the main body portion 30a in the vehicle width direction. The front end portion of the left and right side portions 30b, 30b extends in the vehicle width direction, and includes a front connection portion 30c that connects the front ends of the left and right side portions 30b, 30b. Sometimes it has a substantially rectangular frame shape.

  An internal combustion multi-cylinder engine 34 is mounted in the engine room 14. The engine 34 is a water-cooled in-line four-cylinder engine and is mounted in the engine room 14 with the engine output shaft directed in the vehicle width direction as best seen in FIG. That is, the engine 34 mounted in the engine room 14 is a horizontal reciprocating engine, and a transaxle 36 is connected to the rear end of the engine 34. In other words, the engine 34 and the transaxle 36 are arranged side by side in the vehicle width direction, and the engine output is distributed to the left and right front wheels 32 via a differential gear 38 (FIG. 1) built in the transaxle 36. This automobile is a front-wheel drive type vehicle, but the present invention can also be applied to a four-wheel drive type vehicle.

  The engine 34 is a water-cooled engine, and the cooling water of the engine 34 is cooled by a radiator 40 fixed to a shroud panel (not shown) between the front end portions of the left and right front side frames 24.

  The horizontally placed engine 34 employs a front intake and a rear exhaust type (FIG. 1). An intake pipe 42 is connected to the front surface of the cylinder head of the engine 34 and an exhaust pipe 44 is connected to the rear surface. ing.

  Referring to FIG. 2, in the perimeter frame 30, the front ends of the left and right side portions 30b are connected to the front side frame 24 by the first bolts 46, and the left and right rear ends of the main body 30a are the second bolts. 48 are connected to the left and right floor frames 50. This will be described in detail later. Reference numeral 52 in FIG. 2 indicates a side sill extending along the left and right side edges of the floor panel 50.

  The perimeter frame 30 is provided with vehicle width direction inner end pivot points 56a, 58a of the first and second lower arms 56, 58 included in the suspension mechanism 54 of the front wheel 32, and is located relatively forward. The pivot point 56a of the first lower arm 56 is disposed on the left and right side portions 30b of the perimeter frame 30, and the pivot point 58a of the second lower arm 58 located rearward is disposed on the left and right ends of the main body portion 28a of the perimeter frame 30. (Fig. 2). In the figure, reference numeral 60 indicates a steering link mechanism.

  3 and 4 are diagrams showing a structure for connecting the front end portion of the perimeter frame 30 to the front side frame 24. FIG. Referring to FIGS. 3 and 4, a first bracket 62 extending downward is provided at the front end portion of the front side frame 24. On the other hand, a second bracket 64 extending upward is provided at the front end portion of the perimeter frame 30, and a rubber bush 66 is disposed on the second bracket 64. The front end portion of the perimeter frame 30 and the front end portion of the front side frame 24 above the perimeter frame 30 are connected to each other via a long bolt 46 and a rubber bush 66. In FIG. 3, reference numeral 68 indicates a suspension tower, and reference numeral 70 indicates an apron panel. The apron panel 70 has a lower edge welded to the front side frame 24, and an apron reinforcement 72 is disposed on the upper edge of the apron panel 70.

  FIG. 5 is a view showing a structure for connecting the rear end portion of the perimeter frame 30 to the floor frame 50. Referring to FIG. 5, the front end of floor panel 16 is extended forward by kick-up panel 74. The kick-up panel 74 extends obliquely downward from the front toward the rear, and its front end is joined to the lower end of the dash panel 10. A cross section taken along VI-VI in FIG. 5 is shown in FIG. 6, and a cross section taken along VII-VII in FIG. 5 is shown in FIG. FIG. 8 shows a cross section taken along the line VIII-VIII in FIG.

  With reference to FIGS. 5 and 8, the floor frame 50 is extended forward by an extended floor frame 76 extending along the kick-up panel 74. The extension floor frame 76 is formed with a stepped portion 76a having a shape cut out forward on the lower surface thereof. The rear end of the perimeter frame 30 is received by the stepped portion 76a and is extended by the second bolt 48. It is fixed to the lower surface of the frame 76. As can be seen from FIG. 8, a sleeve 80 is disposed at the rear end of the perimeter frame 30 via a rubber bush 78, and the second bolt 48 is inserted into the sleeve 80 and attached to the extended floor frame 76. It is screwed onto a nut 82 that has been welded in advance. In FIG. 8, reference numeral 84 denotes a reinforcing panel.

  Referring again to FIGS. 1 and 3 to 5, a collision load transmission member 84 is interposed at the front end portion of the perimeter frame 30 between the front side frame 24 positioned above the perimeter frame 30. The collision load transmission member 84 has an axis extending obliquely upward and rearward from the perimeter frame 30, and the collision load input to the perimeter frame 30 is transmitted to the front side frame 24 by the collision load transmission member 84. .

  The collision load transmission member 84 has a lower end portion extending obliquely rearward and upward from an upper surface of the front end portion of the perimeter frame 30, specifically, a base portion of the second bracket 64 of the perimeter frame 30, and an upper end thereof is a front end. It is connected to the lower surface of the side frame 24. In the embodiment, the collision load transmitting member 84 connects the first closed cross-section member 86 on the perimeter frame 30 side and the second closed cross-section member 88 on the front side frame 24 side to each other using a bolt / nut combination 90. It is comprised by.

  The first closed cross-section member 86 may have a substantially right-angled triangle shape with the rear surface standing upright, or may have a shape extending obliquely upward and rearward, but its lower end is a perimeter frame. 30 and the second bracket 64 are arc welded. The first closed cross-section member 86 is formed with a first flange 86a facing rearward at its upper end. On the other hand, the second closed cross-section member 88 has a shape in which an upper end thereof is arc-welded to the lower surface of the front side frame 24 and extends obliquely downward and forward, and a second flange facing forward is provided at the lower end thereof. 88a is formed, and these first and second flanges 86a and 88a are opposed to each other in a vertical plane in this embodiment. Referring to FIG. 9, an elastic sheet 92 is interposed between the first and second flanges 86 a and 88 a of the first and second closed cross-section members 86 and 88. By interposing the elastic sheet 92 in this way, the degree of freedom of connection between the first and second flanges 86a and 88a can be improved without impairing the collision load transmission function of the collision load transmission member 84.

  Referring to FIG. 1, reference numeral 94 indicates an engine mount member. The power plant including the horizontal engine 34 and the transaxle 36 is mounted on the left and right front side frames 24 via mount members 94 at one end and the other end in the output shaft direction, that is, the vehicle width direction. Here, as a collision energy absorbing structure of the front side frame 24, the front end portion of the front side frame 24 is set as a buckling region A, and a region behind the buckling region A is set as a bending region B. When a collision load of frontal collision is applied to the front side frame 24, the buckling region A buckles, and then the rear bending region B is bent three-dimensionally to absorb the collision energy.

  Still referring to FIG. 1, the upper end of the above-described collision load transmitting member 84 is preferably connected to the rear end of the buckling region A or the boundary between the buckling region A and the bending region B or the front end of the bending region B. . In addition, the connection portion for the front side frame 24 is set so that the upper end of the collision load transmission member 84 is preferably located at a position offset forward from the engine mount member 94.

  If the collision load input to the front side frame 24 through the collision load transmission member 84 is absorbed using the buckling area A of the front side frame 24 with respect to the connecting portion at the upper end of the collision load transmission member 84, buckling is possible. The upper end of the collision load transmission member 84 is connected to the center portion in the front-rear direction of the region A. In this case, the collision load transmission member 84 is disposed in an upright state, and the collision load transmission member 84 is disposed. Thus, the collision load vector input to the front side frame 24 crosses the axis of the front side frame 24 at a large angle, and the load transmission in the axial direction of the front side frame 24 deteriorates.

  When the rising angle of the collision load transmission member 84 is reduced with respect to the connection portion at the upper end of the collision load transmission member 84, the load transmission in the axial direction of the front side frame 24 becomes smooth. With this in mind, the connecting portion of the upper end of the collision load transmitting member 84 is the rear end of the buckling area A of the front side frame 24 or the boundary between the buckling area A and the bending area B or the front end of the bending area B. It becomes. When the collision load transmitting member 84 is connected to the boundary between the buckling area A and the bending area B of the front side frame 24 or the front end of the bending area B, the axis of the front side frame 24 in the bending area B can be understood from FIG. In order to avoid the interference with the vertical movement trajectory of the front wheel drive shaft caused by the stroke of the front wheel suspension mechanism 54, a mountain-like line is drawn so that the rising angle of the collision load transmission member 84 can be reduced. In addition, there is an advantage that load transmission in the axial direction of the front side frame 24 becomes smooth. However, when absorbing the load input to the front side frame 24 from the collision load transmitting member 84, energy absorption cannot be expected due to buckling of the buckling region A of the front side frame 24.

  The buckling area A and the bending area B of the front side frame 24 are configured so that the most efficient energy absorption is performed when a collision load is input from the front end of the front side frame 24 due to a full-wrap frontal collision and an offset frontal collision. Although designed, the bending area B in the embodiment is such that the collision load is directly applied to the bending area B of the front side frame 24 through the perimeter frame 30 and the collision load transmitting member 84 by the pole collision without passing through the buckling area A. When the power is input, the energy can be designed to be absorbed efficiently by bending by the front side frame 24. Therefore, the collision load can be efficiently absorbed by the front side frame 24 regardless of the mode of the full-wrap frontal collision, offset frontal collision, or pole collision.

  In a frontal collision, for example, when a pole or the like collides with the center in the vehicle width direction, the collision load is input to the left and right crash cans 28 via the bumper reinforcement 26, and the crash cans 28 are buckled. Is input to the front side frame 24. Further, when the vehicle width direction center portion of the bumper reinforcement 26 is bent and deformed rearward due to the collision of the pole, the pole collides with the perimeter frame 30, and this collision load is applied to the left and right side portions of the perimeter frame 30. Input to 30b.

  Part of the collision load input to the left and right side portions 30 b of the perimeter frame 30 is distributed to the front side frame 24 by the collision load transmission member 84. Since the axis of the collision load transmission member 84 extends obliquely upward and rearward from the perimeter frame 30 and intersects the front side frame 24, in other words, the collision load transmission path by the collision load transmission member 84 is the front side frame. 24, the collision load input from the perimeter frame 30 to the front side frame 24 via the collision load transmission member 84 is applied to the front side frame 24 directly. The collision energy can be absorbed using the collision energy absorption function by the portion of the front side frame 24 that is joined to the load and behind the load.

  Therefore, in the event of a pole collision, most of the collision energy can be absorbed by the front side frame 24 until the timing at which the pole enters the engine room 14 and collides with the power plant including the engine 34.

  Further, by disposing the engine mount member 94 (FIG. 1) behind the upper end of the collision load transmission member 84, the pole retracts the power plant, and the load accompanying the retreat of the engine passes through the engine mount member 94. Thus, the collision energy can be absorbed using the front side frame 24 before the timing of transmission to the front side frame 24.

  Of course, even in a full-wrap frontal collision and offset frontal collision, when a collision load is input to the perimeter frame 30, a part of the collision load can be absorbed by the front side frame 24.

It is the figure which looked at the vehicle body front part structure of the Example from the side. It is the bottom view which looked at the body front part structure of the example from the lower part. It is the figure which looked at the front end part of the front side frame and the perimeter frame from diagonally forward outside the vehicle. It is the figure which looked at the front-end part of the front side frame and the perimeter frame from the diagonally back on the engine room side. It is the figure which looked at the rear end part of the front side frame and the perimeter frame from the side. It is sectional drawing of the front side frame along the VI-VI line of FIG. It is sectional drawing of the floor frame extension part along the VII-VII line of FIG. FIG. 6 is a cross-sectional view taken along line VIII-VIII in FIG. 5, illustrating a connection structure of a rear end portion of the perimeter frame. It is a principal part expansion perspective view for demonstrating the structure of the collision load transmission member extended diagonally upward and back from the front-end part of a perimeter frame, and an upper end being connected with the lower surface of a front side frame.

Explanation of symbols

14 Engine room 24 Front side frame 26 Bumper reinforcement 28 Crash can 30 Perimeter frame (subframe)
34 Engine 36 Transaxle 84 Collision load transmitting member 86 First closed section member (perimeter frame side)
86a First flange of vertical surface 88 Second closed cross-section member (front side frame side)
88a Vertical flange second flange 92 Elastic sheet 94 Engine mount member

Claims (5)

Left and right front side frames extending in the longitudinal direction of the vehicle body and having a closed cross-sectional structure in an engine room where a power plant including an engine is disposed;
In the vehicle body front part structure, which is disposed below the left and right front side frames and has a substantially rectangular frame-shaped subframe in plan view,
The front side frame buckles with respect to the collision load from the front and absorbs the collision energy, and is located behind and bends with respect to the collision load from the front to absorb the collision energy. It has a collision energy absorption structure with a bending area,
The sub-frame is a front connecting portion that connects left and right side portions extending in the front-rear direction along the left and right front side frames and a front end of the left and right side portions, A front connection portion extending in the vehicle width direction at a lower position of the front end portion of each buckling region,
The vehicle body front structure is
Further comprising a collision load transmission member extending toward the left and right front side frame from the front end portion of the side portions of the left and right of the sub-frame,
The collision load transmitting member has an axis extending obliquely upward and rearward,
The upper ends of the left and right collision load transmitting members respectively correspond to the rear end of the buckling region of the left and right front side frames, the boundary between the buckling region and the bending region, or the front end of the bending region. The vehicle body front part structure characterized by being connected to the lower surface of the vehicle. The collision load transmission member includes a first member on the subframe side and a second member on the front side frame side,
Both the first and second members have a closed cross-sectional structure;
The first member has an axis extending obliquely upward and rearward from the front end of the subframe,
The second member has an axis extending obliquely downward and forward from the lower surface of the front side frame,
2. The vehicle body front structure according to claim 1, wherein an upper end of the first member and a lower end of the second member are opposed to each other on a first surface and a second surface that extend in a vertical direction . A first flange facing backward is formed at the upper end of the first member, and a first surface extending up and down is constituted by the first flange ,
A second flange facing forward is formed at the lower end of the second member, and a second surface extending vertically is constituted by the second flange .
The vehicle body front part structure according to claim 2 , wherein the first and second flanges are connected in a state of facing each other. The vehicle body front part structure according to claim 3 , wherein an elastic member is interposed between the first and second flanges. The power plant is mounted on the front side frame via a mount member,
The vehicle body front structure according to any one of claims 1 to 4, wherein the mount member is disposed at a position offset rearward from a position where the collision load transmission member joins the front side frame.

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