Patent Description:
In a vehicle body front section structure disclosed in <CIT>, a front bumper is attached to a front end of a chassis frame (front side frames) through a bumper stay. The bumper stay has an accordion-shaped portion. Main sills (front side members) are disposed at a vehicle upper side of the front side frames further toward a vehicle rear side than the bumper stay. A front panel configuring a floor section of a driving seat is fixed to upper faces of the front side members. Front end portions of the front side members are joined to front end portions of the front side frames through a pair of cab hinge brackets (coupling members). A front cross member that is open toward a vehicle front side is joined to front ends of the front side members. A front member is joined to a front section of the front cross member. The front member includes a forward-extending portion formed with lateral beads.

In this vehicle body front section structure, in cases in which dynamic external force has acted on the vehicle body, the accordion-shaped portion of the bumper stay is compressed in a vehicle front-rear direction, or the lateral beads break, and dynamic external force is absorbed as a result. Since a range at the vehicle rear side of the accordion-shaped portion and the lateral beads is very strong in the vehicle front-rear direction, there is little damage thereto. <CIT> discloses a vehicle body front structure of cab-over vehicle. <CIT> discloses a collision protected front frame structure of a truck. <CIT> discloses a chassis frame structure of a truck.

In the above related art, dynamic external force toward the vehicle body is absorbed over a narrow range further toward the vehicle front side than the front side frames and the front cross members. However, if for example the vehicle were to collide at high speed, the collision load could not be fully absorbed within this range, and damage in a range further toward the vehicle rear side than this range would increase. Thus, there is room for improvement from the perspective of improving collision load absorption performance.

In consideration of the above circumstances, the present disclosure obtains a vehicle front section structure capable of improving collision load absorption performance.

Besides, a vehicle front section structure of a first aspect of the present disclosure includes left and right front side frames, left and right front side members, and left and right coupling members. The left and right front side frames extend along a vehicle front-rear direction at both side sections in a vehicle width direction of a front section of a vehicle, with a deformation portion configured to undergo compression deformation in the vehicle front-rear direction at a time of head-on collision of the vehicle provided at a front end portion of each of the front side frames. The left and right front side members extend along the vehicle front-rear direction at a vehicle upper side with respect to the left and right front side frames, and are configured to support a floor section of a vehicle cabin. The left and right coupling members connect front sections of the left and right front side members and the respective deformation portions, and are configured so as to more readily undergo plastic deformation under a collision load at a time of head-on collision than the left and right front side members.

In the first aspect, the deformation portions are respectively provided at the front end portions of the left and right front side frames that extend along the vehicle front-rear direction at both vehicle width direction side sections of the front section of the vehicle. The left and right deformation portions undergo compression deformation in the vehicle front-rear direction in a vehicle head-on collision. The left and right front side members extend along the vehicle front-rear direction at the vehicle upper side with respect to the left and right front side frames. The floor section of the vehicle cabin is supported by these front side members. The front sections of the left and right front side members and the corresponding left and right deformation portions are connected by the left and right coupling members. Thus, the front sections of the left and right front side members are supported by the left and right deformation portions through the left and right coupling members. The left and right coupling members are configured so as to more readily undergo plastic deformation under collision load at a time of head-on collision than the left and right front side members, and so undergo plastic deformation when the left and right deformation portions undergo compression deformation. Thus, even in configurations in which the left and right coupling members are connected to the corresponding left and right deformation portions, the left and right coupling members can be prevented from hindering compression deformation of the left and right deformation portions. This enables deformation stroke of the left and right deformation portions to be set longer in the vehicle front-rear direction. Moreover, the left and right coupling members can also be utilized as members to absorb collision load. This enables collision load absorption performance to be improved.

A vehicle front section structure of a second aspect of the present disclosure is the first aspect, wherein the left and right coupling members are oriented so as to slope with an upward gradient on progression toward a vehicle rear side.

In the second aspect, the left and right coupling members that connect between the deformation portions provided to front sections of the left and right front side frames and the front sections of the left and right front side members are oriented so as to slope with an upward gradient on progression toward the vehicle rear side. This enables upper end portions of the left and right coupling members to be coupled to vehicle front-rear direction intermediate portions of the front sections of the corresponding left and right front side members. This enables flexing of these intermediate portions to be suppressed under normal circumstances by the left and right coupling members.

A vehicle front section structure of a third aspect of the present disclosure is the second aspect, wherein a front cross member that extends along the vehicle width direction is joined to front end portions of the left and right front side members. End portions of the front cross member in the vehicle width direction are respectively supported by the left and right deformation portions via left and right pillar members. The left and right coupling members are disposed at the vehicle rear of the left and right pillar members, and span, as bracing, between the left and right pillar members and the corresponding left and right front side members.

In the third aspect, both vehicle width direction end portions of the front cross member that are joined to the front end portions of the left and right front side members are supported by the respective deformation portions of the left and right front side frames through the left and right pillar members. The left and right coupling members are disposed at the vehicle rear of the left and right pillar members, and span in the form of bracing between the left and right pillar members and the corresponding left and right front side members. This enables the left and right pillar members and the left and right front side members to be reinforced under normal circumstances by the left and right coupling members serving as bracing.

A vehicle front section structure of a fourth aspect of the present disclosure is any one of the first aspect to the third aspect, wherein respective rear sections of the left and right front side frames and respective rear sections of the left and right front side members each include a kick section that slopes with a downward gradient on progression toward a vehicle rear side.

In the fourth aspect, in a vehicle head-on collision, the left and right front side frames and the left and right front side members undergo deformation at the respective kick sections sloped in the above-described manner. This deformation also enables collision load to be absorbed, thereby enabling collision load absorption performance to be further improved. Moreover, as a result of this deformation, the left and right front side frames and the left and right front side members are displaced obliquely toward the vehicle upper-rear side in a parallel or substantially parallel state. This enables the floor section of the vehicle cabin supported by the left and right front side members to be made to retreat obliquely toward the vehicle upper-rear side, namely toward the opposite side to an object that has collided with the vehicle. Occupant safety is better secured as a result.

A vehicle front section structure of a fifth aspect of the present disclosure is the fourth aspect, further including a power unit that is disposed between the left and right front side frames and that is supported by the left and right front side frames.

In the fifth aspect, the left and right front side frames and the left and right front side members undergo deformation at the respective kick sections in a vehicle head-on collision, and are displaced obliquely toward the vehicle upper-rear side in a parallel or substantially parallel state. When this occurs, the power unit disposed between the left and right front side frames and supported by the left and right front side frames is displaced obliquely toward the vehicle upper-rear side together with the floor section of the vehicle cabin supported by the left and right front side members. This enables the power unit to be prevented from crashing into the floor section of the vehicle cabin, thereby enabling damage to the power unit as a result of such a collision to be prevented.

A vehicle front section structure of a sixth aspect of the present disclosure is the fourth aspect or the fifth aspect, further including a cross member that connects front end portions of the respective kick sections of the left and right front side members in the vehicle width direction.

In the sixth aspect, the front end portions of the respective kick sections of the left and right front side members are connected in the vehicle width direction by the cross member. This for example enables the deformation at the respective kick sections of the left and right front side members to be stabilized.

A vehicle front section structure of a seventh aspect of the present disclosure is the sixth aspect, further including a seat frame that is configured to support a seat of the vehicle and has a front end portion supported by the cross member.

In the seventh aspect, the front end portion of the seat frame that supports the vehicle seat is supported by the cross member. In a vehicle head-on collision, the left and right front side members undergo deformation at the respective kick sections, and the cross member is displaced obliquely toward the vehicle upper-rear side together with the left and right front side members and the seat frame. This enables the seat supported by the seat frame to be made to retreat toward the opposite side to a colliding object.

A vehicle front section structure of an eighth aspect of the present disclosure is any one of the first aspect to the seventh aspect, wherein each of the left and right front side members forms a closed cross-section together with the floor section, and each of the left and right coupling members includes a portion formed with an open cross-section.

Since the eighth aspect is configured as described above, the left and right coupling members are easily made to more readily undergo plastic deformation under collision load at a time of head-on collision than the left and right front side members.

As described above, the vehicle front section structure according to the present disclosure enables collision load absorption performance to be improved.

Explanation follows regarding a vehicle front section structure <NUM> according to an exemplary embodiment of the present disclosure, with reference to <FIG>. Note that some of the reference numerals may be omitted from the drawings in order to facilitate viewing of the drawings. In the respective drawings, the arrow FR, the arrow LH, and the arrow UP respectively indicate a vehicle front side (direction of progress), a vehicle left side, and a vehicle upper side, as appropriate. Moreover, unless specifically stated otherwise, simple reference to front and rear, left and right, and up and down directions refers to front and rear in a vehicle front-rear direction, left and right in a vehicle left-right direction (vehicle width direction), and up and down in a vehicle vertical direction.

As illustrated in <FIG>, a vehicle <NUM> applied with the vehicle front section structure <NUM> according to the present exemplary embodiment is what is referred to as a body-on-frame vehicle in which a vehicle body <NUM> is supported by a ladder frame <NUM>. As an example, the vehicle <NUM> is a bus. Although not illustrated in the drawings, the vehicle body <NUM> of the vehicle <NUM> has a substantially rectangular block-shaped external profile. As an example, the vehicle <NUM> is an electric vehicle. First, explanation follows regarding an outline of a framework structure of the vehicle <NUM>.

The ladder frame <NUM> includes a left and right pair of side frames <NUM> and plural cross members <NUM>, <NUM>. The left and right side frames <NUM> extend along the front-rear direction at both vehicle width direction side sections of the vehicle <NUM>. The plural cross members <NUM>, <NUM> each extend along the vehicle width direction so as to be arrayed in the front-rear direction with a spacing therebetween. The left and right side frames <NUM> are connected in the vehicle width direction by the plural cross members <NUM>, <NUM>.

The left and right side frames <NUM> are respectively configured by left and right front side frames <NUM>, left and right central side frames <NUM>, and left and right rear side frames (not illustrated in the drawings). The left and right front side frames <NUM> extend along the front-rear direction at both vehicle width direction side sections of a front section of the vehicle <NUM>. The left and right central side frames <NUM> extend along the front-rear direction at both vehicle width direction side sections of a front-rear direction central section of the vehicle <NUM>. The left and right rear side frames extend along the front-rear direction at both vehicle width direction side sections of a rear section of the vehicle <NUM>. The front side frames <NUM>, the central side frames <NUM>, and the rear side frames are each formed in an angular tube shape using a steel material or the like, and each have a rectangular closed cross-section profile as viewed along the front-rear direction. Note that plural non-illustrated cross members are also provided between the left and right central side frames <NUM>, and between the left and right rear side frames.

A front section 18F of each of the left and right front side frames <NUM> extends in a straight line along the front-rear direction. A front end portion of each of the front sections 18F (namely, a front end portion of each of the left and right front side frames <NUM>) configures a deformation portion 18F1 that undergoes axial compression deformation in the front-rear direction at a time of head-on collision of the vehicle <NUM>. Plural beads <NUM> that extend along the vertical direction as an example are formed arrayed along the front-rear direction on left and right side faces of each of the deformation portions 18F1. The deformation portions 18F1 are therefore weaker with respect to load in the front-rear direction than other locations of the respective front sections 18F. Front-rear direction intermediate portions of the respective front sections 18F are connected in the vehicle width direction by the cross member <NUM>. A suspension tower <NUM> is fixed to a vehicle width direction outer face of each of the front sections 18F.

A front side portion of a rear section 18R of each of the left and right front side frames <NUM> configures a kick section 18R1 that slopes with a downward gradient on progression toward the rear side. A rear side portion of the rear section 18R extends in a straight line along the front-rear direction. Each of the rear sections 18R is bent into substantially a crank shape at bend portions <NUM>, <NUM> on both front and rear sides of the kick section 18R1. The bend portion <NUM> on the front side is bent so as to bulge toward the upper-rear side, whereas the bend portion <NUM> on the rear side is bent so as to bulge toward the lower-front side. Front portions of the respective kick sections 18R1 (namely, front portions of the respective rear sections 18R) are connected in the vehicle width direction by the cross member <NUM>. Front end portions of the left and right central side frames <NUM> are joined to rear end portions of the respective rear sections 18R.

A motor <NUM> for causing the vehicle <NUM> to travel is disposed between the left and right front side frames <NUM>. The motor <NUM> is supported by the left and right front side frames <NUM> through the cross members <NUM>, <NUM> and a non-illustrated support member or the like. An electronic unit <NUM> that controls power supplied to the motor <NUM> is disposed above the motor <NUM>. The electronic unit <NUM> is supported by the left and right front side frames <NUM> through a support frame <NUM>. As an example, the support frame <NUM> includes a front and rear pair of cross frame sections (not allocated reference numerals) that span between the left and right front side frames <NUM>, and a left and right pair of side frame sections (not allocated reference numerals) that span between the front and rear cross frame sections, so as to have a ladder shape in plan view. The motor <NUM> and the electronic unit <NUM> configure a power unit <NUM>.

The vehicle body <NUM> is supported from the lower side by the ladder frame <NUM> with the above configuration. The vehicle body <NUM> includes floor paneling <NUM> configuring floor sections of a vehicle cabin <NUM>. The floor paneling <NUM> includes a front floor panel <NUM> configuring a floor section at a front section of the vehicle cabin <NUM>, a central floor panel <NUM> configuring a floor section at a front-rear direction intermediate section of the vehicle cabin <NUM>, and a rear floor panel (not illustrated in the drawings) configuring a floor section at a rear section of the vehicle cabin <NUM>. The front floor panel <NUM>, the central floor panel <NUM>, and the rear floor panel are each configured of sheet steel or the like.

A front section of the front floor panel <NUM> configures a driving seat floor section 46F extending along the front-rear direction and the vehicle width direction. A rear section of the front floor panel <NUM> configures a sloped section 46R that slopes with a downward gradient on progression toward the vehicle rear side. The driving seat floor section 46F is disposed spaced apart from and at the upper side with respect to the front sections 18F of the left and right front side frames <NUM>, and the sloped section 46R is disposed spaced apart from and at the upper side with respect to the rear sections 18R of the left and right front side frames <NUM>. The above-mentioned electronic unit <NUM> is disposed below the driving seat floor section 46F. A front end portion of the central floor panel <NUM> is joined to a rear end portion of the sloped section 46R. The central floor panel <NUM> extends along the front-rear direction and the vehicle width direction. A non-illustrated battery that stores power for supply to the above-mentioned motor <NUM> is disposed below the central floor panel <NUM>.

The front floor panel <NUM> is supported by the left and right front side frames <NUM> through a left and right pair of front side members <NUM>. The left and right front side members <NUM> extend along the front-rear direction at the upper side and vehicle width direction outside with respect to the left and right front side frames <NUM>. The left and right front side members <NUM> are each manufactured by for example pressing sheet steel, and are joined to a lower face of the front floor panel <NUM> by a means such as welding. Specifically, as illustrated in <FIG>, each of the front side members <NUM> has a hat-shaped cross-section profile open toward the upper side as viewed along the front-rear direction, and is joined to the lower face of the front floor panel <NUM> at left and right flanges <NUM> provided at upper end portions of the front side member <NUM>. Thus, a closed cross-section extending along the vehicle front-rear direction is formed by each of the front side members <NUM> and the front floor panel <NUM>.

A front section 48F of each of the left and right front side members <NUM> extends in a straight line along the front-rear direction, and is joined to a lower face of the driving seat floor section 46F of the front floor panel <NUM>. A rear section 48R of each of the left and right front side members <NUM> configures a kick section 48R that slopes with a downward gradient on progression toward the vehicle rear side, and is joined to a lower face of the sloped section 46R of the front floor panel <NUM>. Each of the kick sections 48R is bent into substantially a crank shape at bend portions <NUM>, <NUM> at both front and rear sides. The bend portion <NUM> on the front side is bent so as to bulge toward the upper-rear side, whereas the bend portion <NUM> on the rear side is bent so as to bulge toward the lower-front side.

A front cross member <NUM> that extends along the vehicle width direction is disposed at front end portions of the left and right front side members <NUM>. The front cross member <NUM> is configured of sheet steel or the like, and has a hat-shaped cross-section profile open toward the front side as viewed along the vehicle width direction. A flange that for example overlays a rear face of the front cross member <NUM> is provided at the front end portion of each of the left and right front side members <NUM>, and the flange is fixed to the rear face of the front cross member <NUM> by a means such as bolt-fastening. The front end portions of the left and right front side members <NUM> are thereby connected in the vehicle width direction by the front cross member <NUM>.

Both vehicle width direction end portions of the front cross member <NUM> are supported by the front end portions (namely, the respective deformation portions 18F1) of the left and right front side frames <NUM> through left and right front pillar members <NUM>. The left and right front pillar members <NUM> correspond to "left and right pillar members" of the present disclosure. Each of the left and right front pillar members <NUM> is for example formed by pressing sheet steel, and has a box shape open toward the front and upper sides. For example, a non-illustrated flange formed to an upper end portion of each of the front pillar members <NUM> is fixed to the front cross member <NUM> by a means such as welding or bolt-fastening. A lower end portion of each of the front pillar members <NUM> is fixed to the corresponding front side frame <NUM> through a bracket <NUM>. The bracket <NUM> is fixed to a vehicle width direction outside face of the corresponding deformation portion 18F1 by a means such as welding. The front pillar member <NUM> is mounted on an upper face of the corresponding bracket <NUM>, and is fixed to the bracket <NUM> by a means such as bolt-fastening.

Front end portions of the respective kick sections 48R of the left and right front side members <NUM> are supported by the left and right front side frames <NUM> through left and right rear pillar members <NUM>. Each of the left and right rear pillar members <NUM> is for example formed by pressing sheet steel, and has a box shape open toward the vehicle width direction center side and the upper side. For example, a flange formed to an upper end portion of each of the rear pillar members <NUM> is fixed to the front end portion of the corresponding kick section 48R by a means such as welding. A lower end portion of each of the rear pillar members <NUM> is fixed to the corresponding front side frame <NUM> through a bracket <NUM>. The bracket <NUM> is fixed to a vehicle width direction outside face of the front end portion of the corresponding kick section 48R by a means such as welding. The corresponding rear pillar member <NUM> is mounted on an upper face of the bracket <NUM>, and is fixed to the bracket <NUM> by a means such as bolt-fastening.

The left and right front side members <NUM> are supported from the lower side by the left and right front side frames <NUM> through the front cross member <NUM>, the front pillar members <NUM>, the brackets <NUM>, the rear pillar members <NUM>, and the brackets <NUM>. The front floor panel <NUM> is supported from the lower side by the left and right front side members <NUM>. An instrument panel <NUM> is mounted and fixed to an upper face of the front section of the front floor panel <NUM>.

The front end portions of the respective kick sections 48R of the left and right front side members <NUM> are connected in the vehicle width direction by a seat cross member <NUM> (see <FIG> and <FIG>). The seat cross member <NUM> corresponds to a "cross member" of the present disclosure. The seat cross member <NUM> is for example formed in an angular tube shape using a steel material, and extends along the vehicle width direction. Both vehicle width direction end portions of the seat cross member <NUM> are joined to the front end portions of the respective kick sections 48R by a means such as welding. A rear end portion of the driving seat floor section 46F is joined to an upper face of the seat cross member <NUM> by a means such as welding. The seat cross member <NUM> supports a front end portion of a seat frame <NUM> from the lower side.

The seat frame <NUM> is a frame that supports a driving seat <NUM>, configuring a seat of the vehicle <NUM>, from the lower side. The seat frame <NUM> includes a left and right pair of vertical sections <NUM> extending along the vertical direction, and a horizontal section <NUM> extending rearward from upper end portions of the left and right vertical sections <NUM>. Brace portions <NUM> span in the form of bracing between lower end portions of the vertical sections <NUM> and front-rear direction intermediate portions of the horizontal section <NUM>. The lower end portions of the vertical sections <NUM> are fixed to the rear end portion of the driving seat floor section 46F and to the seat cross member <NUM> by a means such as bolt-fastening. A rear end portion of the horizontal section <NUM> is fixed to vertical direction intermediate portions of a left and right pair of support pillars <NUM> that project upward from the front end portion of the central floor panel <NUM>.

The left and right support pillars <NUM> are for example each formed in an angular tube shape using a steel material or the like, extend along the vertical direction, and are arrayed in the vehicle width direction with a spacing therebetween. Plural passenger seats <NUM> are disposed at the rear side of the left and right support pillars <NUM>. The plural passenger seats <NUM> are arranged in a row along the vehicle width direction, and are fixed to the left and right support pillars <NUM> through brackets or the like. Although not illustrated in the drawings, plural other passenger seats are provided in a rear area inside the vehicle cabin <NUM>.

As illustrated in <FIG>, <FIG>, <FIG>, and <FIG>, in the vehicle front section structure <NUM> according to the present exemplary embodiment, the deformation portions 18F1 of the left and right front side frames <NUM> and the corresponding front sections 48F of the left and right front side members <NUM> are connected by left and right coupling members <NUM>. As an example, the vehicle front section structure <NUM> is configured with left-right symmetry.

As illustrated in <FIG> and <FIG>, each of the left and right coupling members <NUM> includes an upper fixing portion <NUM> fixed to the front section 48F of the corresponding left or right front side member <NUM>, a lower fixing portion <NUM> fixed to the left or right front pillar member <NUM> and the corresponding bracket <NUM>, and an intermediate coupling portion <NUM> that couples the upper fixing portion <NUM> and the lower fixing portion <NUM> together. The upper fixing portion <NUM>, the lower fixing portion <NUM>, and the intermediate coupling portion <NUM> are each manufactured by for example pressing sheet steel.

As illustrated in <FIG>, the upper fixing portion <NUM> is formed in an elongated shape with its length along the vehicle front-rear direction, and has a substantially L-shaped cross-section profile as viewed along the front-rear direction. The upper fixing portion <NUM> includes as integral parts a lower wall <NUM> overlaid on a lower face of the corresponding front side member <NUM>, a side wall <NUM> that extends toward the upper side from a vehicle width direction outside end portion of the lower wall <NUM> and is overlaid on a vehicle width direction outside face of the corresponding front side member <NUM>, and a flange <NUM> that extends toward the vehicle width direction outside from an upper end portion of the side wall <NUM> and is overlaid on a lower face of the flange <NUM> of the corresponding front side member <NUM>. The upper fixing portion <NUM> is fixed to the corresponding front side member <NUM> by a means such as welding. A front portion side of the upper fixing portion <NUM> is bent obliquely toward the lower-front side so as to project obliquely toward the vehicle lower-front side with respect to the corresponding front side member <NUM>. The intermediate coupling portion <NUM> is fixed to this projecting portion.

As illustrated in <FIG>, <FIG>, <FIG>, the intermediate coupling portion <NUM> is formed in an elongated shape, and extends obliquely toward the lower-front side from the projecting portion of the upper fixing portion <NUM>. Similarly to the upper fixing portion <NUM>, the intermediate coupling portion <NUM> has a substantially L-shaped cross-section profile as viewed along its length direction, and includes as integral parts a lower wall <NUM>, a side wall <NUM>, and a flange <NUM>. The lower wall <NUM>, the side wall <NUM>, and the flange <NUM> of the intermediate coupling portion <NUM> are overlaid on the lower wall <NUM>, the side wall <NUM>, and the flange <NUM> of the upper fixing portion <NUM>. As an example, the side wall <NUM> of the intermediate coupling portion <NUM> and the side wall <NUM> of the upper fixing portion <NUM> are fastened and fixed together by a bolt <NUM> (see <FIG> and <FIG>; not allocated a reference numeral in <FIG>), and a nut (not illustrated in <FIG>; not allocated a reference numeral in <FIG>).

As illustrated in <FIG> and <FIG>, the lower fixing portion <NUM> includes as integral parts a fixing wall <NUM> sandwiched between a lower face of the corresponding front pillar member <NUM> and the upper face of the corresponding bracket <NUM>, a sloped wall <NUM> extending obliquely toward the upper-rear side from a rear end of the fixing wall <NUM>, a side wall <NUM> extending toward the front side from a vehicle width direction outside end portion of the sloped wall <NUM>, and a flange <NUM> extending toward the vehicle width direction outside from a front end portion of the side wall <NUM> with a lower end portion connected to a rear end portion of the fixing wall <NUM>. The fixing wall <NUM> is fixed to the lower face of the corresponding front pillar member <NUM> by a means such as welding to the front pillar members <NUM>, and is also fixed to the corresponding bracket <NUM> by a means such as bolt-fastening. The sloped wall <NUM> and the side wall <NUM> of the lower fixing portion <NUM> are overlaid on the lower wall <NUM> and the side wall <NUM> of the intermediate coupling portion <NUM>. As an example, the side wall <NUM> of the lower fixing portion <NUM> and the side wall <NUM> of the intermediate coupling portion <NUM> are fastened and fixed by a bolt <NUM> (see <FIG> and <FIG>; not a allocated reference numeral in <FIG>), and a nut (not illustrated in <FIG>; not allocated a reference numeral in <FIG>).

Each of the coupling members <NUM> with the above configuration is oriented so as to slope with an upward gradient on progression toward the vehicle rear side at the vehicle rear of the corresponding front pillar member <NUM>, and spans in the form of bracing between the front pillar member <NUM> and a front-rear direction intermediate portion of the front section 48F of the corresponding front side member <NUM>. The intermediate coupling portion <NUM> of the coupling member <NUM> and locations peripheral thereto are formed with an L-shaped cross-section profile (namely, an open cross-section profile). The coupling members <NUM> are configured so as to more readily undergo plastic deformation under collision load at a time of head-on collision of the vehicle <NUM> than the front side members <NUM>.

Next, explanation follows regarding operation and advantageous effects of the present exemplary embodiment.

In the vehicle front section structure <NUM> with the above configuration, the deformation portions 18F1 are respectively provided to the front end portions of the left and right front side frames <NUM> that extend along the front-rear direction at both vehicle width direction side sections of the front section of the vehicle <NUM>. The left and right deformation portions 18F1 undergo compression deformation in the front-rear direction in a vehicle head-on collision. The left and right front side members <NUM> extend along the front-rear direction at the upper sides with respect to the left and right front side frames <NUM>. The front floor panel <NUM> of the vehicle cabin is supported by these front side members <NUM>. The front sections 48F of the left and right front side members <NUM> and the corresponding left and right deformation portions 18F1 are connected by the left and right coupling members <NUM>. Thus, the front sections 48F of the left and right front side members <NUM> are supported by the left and right deformation portions 18F1 through the left and right coupling members <NUM>. This enables the supported rigidity of the front floor panel <NUM> by the front sections 48F of the left and right front side members <NUM> under normal circumstances to be increased.

The left and right coupling members <NUM> are configured so as to more readily undergo plastic deformation under collision load at a time of head-on collision than the left and right front side members <NUM>, and so the coupling members <NUM> undergo plastic deformation when the left and right deformation portions 18F1 undergo compression deformation. Thus, even in configurations in which the left and right coupling members <NUM> are connected to the corresponding left and right deformation portions 18F1, the left and right coupling members <NUM> can be prevented from hindering compression deformation of the left and right deformation portions 18F1. This enables deformation stroke of the left and right deformation portions 18F1 to be set longer in the front-rear direction. Moreover, the left and right coupling members <NUM> can also be utilized as members to absorb collision load. This enables collision load absorption performance to be improved.

The left and right coupling members <NUM> are oriented so as to slope with an upward gradient on progression toward the vehicle rear side. This enables upper end portions of the left and right coupling members <NUM> to be coupled to the front-rear direction intermediate portions of the front sections 48F of the corresponding left and right front side members <NUM>. This enables flexing of the front-rear direction intermediate portions of the front sections 48F to be suppressed under normal circumstances by the left and right coupling members <NUM>. The supported rigidity of the front floor panel <NUM> by the front sections 48F can be effectively increased as a result.

Moreover, in the present exemplary embodiment, both vehicle width direction end portions of the front cross member <NUM> that are joined to the front end portions of the left and right front side members <NUM> are supported by the respective deformation portions 18F1 of the left and right front side frames <NUM> through the left and right front pillar members <NUM>. The left and right coupling members <NUM> are disposed at the rear of the left and right front pillar members <NUM>, and span in the form of bracing between the left and right front pillar members <NUM> and the corresponding left and right front side members <NUM>. This enables the left and right front pillar members <NUM> and the left and right front side members <NUM> to be reinforced under normal circumstances by the left and right coupling members <NUM> serving as bracing.

Furthermore, in the present exemplary embodiment, the respective rear sections 18R, 48R of the left and right front side frames <NUM> and of the left and right front side members <NUM> include the kick sections 18R1, 48R that slope with a downward gradient on progression toward the vehicle rear side. Thus, stress concentrates at the bend portions <NUM>, <NUM>, <NUM>, <NUM> of the kick sections 18R1, 48R at a time of head-on collision of the vehicle <NUM>, and the kick sections 18R1, 48R undergo deformation at these bend portions <NUM>, <NUM>, <NUM>, <NUM> (see the front side frame <NUM> and the front side member <NUM> illustrated by double-dotted dashed lines in <FIG>). This deformation also enables collision load to be absorbed, thereby enabling collision load absorption performance to be further improved.

Moreover, as a result of this deformation, the left and right front side frames <NUM> and the left and right front side members <NUM> are displaced obliquely toward the vehicle upper-rear side in a parallel or substantially parallel state. This enables the front floor panel <NUM> (not illustrated in <FIG>) of the vehicle cabin <NUM> supported by the left and right front side members <NUM> to be made to retreat obliquely toward the vehicle upper-rear side, namely toward the opposite side to an object that has collided with the vehicle. Occupant safety is better secured as a result.

Moreover, when the above-described deformation occurs, the power unit <NUM> supported by the left and right front side frames <NUM> is displaced obliquely toward the vehicle upper-rear side together with the front floor panel <NUM> of the vehicle cabin <NUM> supported by the left and right front side members <NUM>. This enables the electronic unit <NUM> of the power unit <NUM> to be prevented from crashing into the lower face of the front floor panel <NUM> of the vehicle cabin <NUM>, thereby enabling damage to the power unit as a result of such a collision to be prevented.

Moreover, in the present exemplary embodiment, the front end portions of the respective kick sections 48R of the left and right front side members <NUM> are connected in the vehicle width direction by the seat cross member <NUM> (see <FIG> and <FIG>). This for example enables the deformation at the respective kick sections 48R of the left and right front side members <NUM> to be stabilized.

Moreover, the seat cross member <NUM> supports the front end portion of the seat frame <NUM> that supports the driving seat <NUM> of the vehicle <NUM>. At a time of head-on collision of the vehicle <NUM>, the left and right front side members <NUM> undergo deformation at the respective kick sections 48R, and the seat cross member <NUM> is displaced obliquely toward the vehicle upper-rear side together with the left and right front side members <NUM> and the seat frame <NUM>. This enables the driving seat <NUM> supported by the seat frame <NUM> to be made to retreat toward the opposite side to the colliding object.

Moreover, in the present exemplary embodiment, the left and right front side members <NUM> each form a closed cross-section profile together with the front floor panel <NUM>, whereas the intermediate coupling portions <NUM> and so on of the left and right coupling members <NUM> are formed with an open cross-section profile. Due to this configuration, the left and right coupling members <NUM> are easily made to more readily undergo plastic deformation under collision load at a time of head-on collision than the left and right front side members <NUM>.

Note that although the left and right coupling members <NUM> are configured including locations formed with an open cross-section profile in the above exemplary embodiment, there is no limitation thereto, and configuration of the left and right coupling members may be modified as appropriate. For example, the left and right coupling members may be manufactured using a tube-shaped material.

Moreover, although the above exemplary embodiment includes the seat cross member <NUM> that connects between the front end portions of the respective kick sections 48R of the left and right front side members <NUM> in the vehicle width direction, and the front end portion of the seat frame <NUM> is supported by the seat cross member <NUM>, there is no limitation thereto. The installation locations of the cross member that connects between the left and right front side members <NUM> in the vehicle width direction and of the seat frame may be modified as appropriate.

Moreover, although the driving seat <NUM> is supported by the seat frame <NUM> in the above exemplary embodiment, there is no limitation thereto, and the seat supported by the seat frame may be a seat other than the driving seat (such as a front passenger seat).

Moreover, although the above exemplary embodiment includes the power unit <NUM> that is disposed between the left and right front side frames <NUM> and is supported by the left and right front side frames <NUM>, there is no limitation thereto. A configuration in which the power unit is installed to a rear section of the vehicle may be employed.

Moreover, although the respective rear sections of the left and right front side frames <NUM> and the respective rear sections of the left and right front side members <NUM> include the kick sections 18R1, 48R in the above exemplary embodiment, there is no limitation thereto. For example, the left and right front side frames may each be formed in a straight line along the vehicle front-rear direction.

Moreover, although the left and right coupling members <NUM> span in the form of bracing between the left and right front pillar members <NUM> (pillar members) and the left and right front side members <NUM> in the above exemplary embodiment, there is no limitation thereto. For example, lower end portions of the left and right coupling members may be directly coupled to deformation portions of the left and right front side frames without being coupled through left and right pillar members.

Claim 1:
A vehicle front section structure (<NUM>), comprising:
left and right front side frames (<NUM>) that extend along a vehicle front-rear direction at both side sections in a vehicle width direction of a front section of a vehicle (<NUM>), with a deformation portion (18F1) provided at a front end portion of each of the front side frames (<NUM>) and configured to undergo compression deformation in the vehicle front-rear direction at a time of head-on collision of the vehicle (<NUM>);
left and right front side members (<NUM>) that extend along the vehicle front-rear direction at a vehicle upper side with respect to the left and right front side frames (<NUM>), and that are configured to support a floor section (<NUM>) of a vehicle cabin (<NUM>);
left and right coupling members (<NUM>) that connect front sections of the left and right front side members (<NUM>) and the respective deformation portions (18F1), and are configured so as to more readily undergo plastic deformation under a collision load at a time of head-on collision than the left and right front side members (<NUM>), and
characterized in that respective rear sections of the left and right front side frames (<NUM>) and respective rear sections of the left and right front side members (<NUM>) each include a kick section (18R1, 48R) that slopes with a downward gradient on progression toward a vehicle rear side,
wherein the kick sections (18R1, 48R) are configured to undergo deformation at a time of a head-on collision of the vehicle (<NUM>) so as to displace the left and right front side frames (<NUM>) and the left and right front side members (<NUM>) obliquely toward the vehicle upper-rear side.