JP7518479B2 - Chassis frame structure - Google Patents

Description

The present invention relates to the frame structure of a vehicle chassis, and in particular to technology for improving collision safety.

A bumper frame is provided at the front of the vehicle, extending in the vehicle width direction to absorb the impact during a frontal collision. The shock absorbing parts of the side members supporting the bumper frame deform during a frontal collision, absorbing the impact and reducing the impact on the passenger compartment, etc.
There are several types of vehicle frontal collisions, such as a so-called full overlap where the two vehicles face each other head-on and collide with each other on their entire faces, and a so-called offset collision where the vehicles collide with only one of the left and right sides, etc. In particular, in the case of an offset collision, a local load is generated at one of the left and right ends of the bumper frame, and it is considered that the buffer parts of the bumper frame and side members are deformed more than expected and are unable to absorb the impact sufficiently.

Therefore, a technology has been developed that provides side stays that extend from a cross member attached to the side member and support the left and right ends of the bumper frame, preventing the shock absorbing parts of the bumper frame and side members from deforming more than expected even when a local load is applied to one of the left and right ends of the bumper frame (Patent Document 1).

Japanese Patent Application Publication No. 10-203411

However, with the technology disclosed in Patent Document 1, in consideration of the load that is applied to the other vehicle in the event of an offset collision, there is a possibility that the load at the positions corresponding to the side members or side stays will be locally high, which is not desirable.
On the other hand, reducing the rigidity of the buffer portions of the side members or the side stays may result in a decrease in impact absorbing performance, so there is room for further improvement.

The present invention was made in consideration of these problems, and its purpose is to provide a frame structure for a vehicle chassis that can reduce the localized load applied to the opposing vehicle (the body struck) while maintaining shock absorption performance during a vehicle collision.

In order to achieve the above object, the frame structure of the chassis of the present invention is a frame structure of the chassis that supports a body of a vehicle, and includes a pair of left and right side members extending in a front-rear direction of the vehicle, a bumper frame that is provided at the outer ends of the side members in the front-rear direction of the vehicle to extend in the vehicle width direction and has an extension portion that extends outward in the vehicle width direction from the side members, a first cross member that is provided between the side members and extends in the vehicle width direction, a mount bracket that is provided between the bumper frame of the side members and the first cross member and supports the body, an extension member that extends outward in the vehicle width direction from a position where the mount bracket of the side member is provided to a position facing the extended portion of the bumper frame on the inner side in the front-rear direction of the vehicle, a pillar member that extends downward from the position where the mount bracket of the side member is provided, and and a second cross member provided at a position where the mount bracket is provided between the first cross member and the bumper frame and extending in the vehicle width direction, wherein the mount bracket has a mount support portion to which a mount member connected to the body is attached, and a front wall portion and a rear wall portion which extend downward from the front and rear of the mount support portion with a gap between them and are joined to the outer side of the side member in the vehicle width direction, the extension member extends from the side member between the front wall portion and the rear wall portion, the second cross member is located below the side member and has left and right ends supported by the pillar members, the pillar members are joined to the side of the side member between the front wall portion and the rear wall portion of the mount bracket, and the extension member is joined to the side member via the pillar member between the front wall portion and the rear wall portion of the mount bracket .

As a result, a mount bracket is provided on the cushioning section which is formed in the side member from the bumper frame to the first cross member and which collapses in the fore-and-aft direction of the vehicle when a predetermined load is applied, and an extension member extends outward in the vehicle width direction from the mount bracket and is positioned inward in the fore-and-aft direction of the bumper frame.This makes it possible to firmly support the extension member while moderately allowing movement of the extension member due to deformation of the cushioning section.
In addition, by making the extension member extend between the front wall portion and the rear wall portion which are joined to the outer side surface of the side member in the vehicle width direction, it is possible to increase the strength of the portion of the side member where the pillar member extends.
In addition, by providing a second cross member located between the first cross member and the bumper frame and extending in the vehicle width direction, it is possible to use the force of the second cross member pressing inward in the vehicle front-rear direction to press the extension member outward in the vehicle front-rear direction. In addition, by positioning the second cross member below the side members and supporting the left and right ends with pillar members extending downward from positions where the mount brackets of the side members are provided, joining the pillar members to the side surfaces of the side members between the front wall portions and the rear wall portions of the mount brackets, and joining the extension members to the side members via the pillar members between the front wall portions and the rear wall portions of the mount brackets, it is possible to transmit the force applied to the second cross member around the pillar members as the axis when the buffer portion collapses to the extension member while allowing the second cross member to swing.

In another aspect, it is preferable that the side member has a buffer portion between the bumper frame and the first cross member, which buckles to absorb impact when a load of a predetermined magnitude or more is applied in the longitudinal direction of the vehicle.
This forms a cushioning section that buckles and absorbs impact when a load of a predetermined amount or more is applied in the fore-and-aft direction of the vehicle between the bumper frame of the side member and the first cross member.When an impact is received by the entire bumper frame, such as in a full overlap collision, the extension member supports the bumper frame, so that the load is applied evenly to the left and right cushioning sections, crushing them equally on both sides.When an impact is received biased toward one side of the bumper frame in the vehicle width direction, such as in an offset collision, the extension member supports the bumper frame, making it possible to reduce the local increase in rigidity at the position corresponding to the cushioning section.

In another aspect, it is preferable that the extension member supports the bumper frame at least when the bumper frame moves inward in the vehicle front-rear direction by a predetermined distance or more.
This makes it possible for the bumper frame to be supported by the extension member at least when the bumper frame moves inward in the fore-and-aft direction of the vehicle by a predetermined distance or more, thereby making it possible for the bumper frame to be supported by the extension member during a relatively large collision in which the bumper frame moves by more than a predetermined distance.

In another aspect, the second cross member is preferably formed with a rigidity reducing portion at the center in the vehicle width direction, which reduces rigidity against bending forces in the vehicle front-rear direction.
As a result, by forming a reduced rigidity section in the center of the second cross member in the vehicle width direction, which reduces the rigidity against forces bending in the fore-and-aft direction of the vehicle, it is possible to use the force that presses the reduced rigidity section of the second cross member toward the center in the fore-and-aft direction of the vehicle during a collision to press the bumper frame outward with the reinforcement section.

According to the frame structure of the present invention, a mount bracket is provided on the buffer section formed in the area from the bumper frame of the side member to the first cross member, which collapses in the longitudinal direction of the vehicle when a predetermined load is applied, and an extension member is provided that extends outward in the transverse direction of the vehicle from the mount bracket and is located inside the transverse direction of the bumper frame. This allows the extension member to be firmly supported by the mount bracket while allowing a moderate amount of movement of the extension member due to deformation of the buffer section. In addition, the extension member is designed to press the bumper frame when the buffer section collapses, so that when the entire bumper frame receives an impact, such as in a full overlap collision, the bumper frame is supported and the buffer section is crushed equally on both sides, and when the impact is biased to one side in the transverse direction of the bumper frame, such as in an offset collision, the extension member supports the bumper frame, reducing the local increase in rigidity at the position corresponding to the buffer section.

This allows the vehicle to maintain its shock absorbing performance during a collision while reducing the localized load on the object being struck.

FIG. 2 is a rear perspective view of the front portion of the vehicle chassis. FIG. FIG. FIG. 2 is an enlarged view of the area A in FIG. 1 is an explanatory diagram illustrating deformation of a front part of a chassis when another vehicle collides with the vehicle from in front of the vehicle in a full overlap manner; 1 is an explanatory diagram illustrating deformation of a front part of a chassis when another vehicle collides with the vehicle from the front in an offset manner; 1 is an explanatory diagram illustrating deformation of a front part of a chassis when another vehicle collides with the vehicle from the front in an offset manner; 1 is an explanatory diagram illustrating deformation of a front part of a chassis when another vehicle collides with the vehicle from the front in an offset manner;

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
1, there is shown a rear perspective view of the front part of a chassis 3 of a vehicle 1. The vehicle 1 is an automobile having a chassis 3 with a frame structure. In other words, the vehicle 1 is configured by mounting a body including a cabin 2, an upper body, an engine, etc. (not shown) on the chassis 3.
The chassis 3 is formed by combining a plurality of frame members, and is the skeleton of the vehicle 1. Specifically, the chassis 3 includes side members 11, a suspension frame 13, a mount bracket 15, a bumper frame 17, and a lower cross member (second cross member) 19.

The side members 11 are arranged in a pair on the left and right sides and are rectangular pillar members made of, for example, iron that extend in the fore-and-aft direction of the vehicle. The side members 11 are located below the center in the vertical direction of the vehicle 1. The pair of left and right side members 11 are fixed to each other by multiple cross member members that extend in the vehicle width direction, such as the suspension frame 13 and the lower cross member 19, so that relative swaying is suppressed.

The suspension frame 13 is a frame that is provided between the side members 11 and includes a front cross member member (first cross member) 13a and a rear cross member member 13b that extend in the vehicle width direction. This suspension frame 13 is provided with a lower arm (not shown) that supports the drive shaft and can reduce vibrations and shocks transmitted from the ground to the vehicle 1.

Referring to Figure 2, a side view of the front part of the chassis 3 is shown. Also, refer to Figure 3, a bottom view of the front part of the chassis 3 is shown. An extension (buffer part) 12 is formed at the front part of the side member 11. This extension 12 is formed in the range from the front end 11a of the side member 11 to the front end of the front cross member member 13a of the suspension frame 13, and is formed so that it buckles to absorb shock when a load of a predetermined magnitude or more is applied in the fore-and-aft direction of the vehicle.

Referring to Figure 4, an enlarged view of range A in Figure 1 is shown. The mount bracket 15 is a frame on which the cabin (body) 2 of the vehicle 1 is placed via a mount member 16. The mount bracket 15 is disposed on the outer side of the pair of left and right side members 11 in the vehicle width direction, between the front end 11a of the side members 11 and the front end of the front cross member member 13a, i.e., in the extension 12.

This mount bracket 15 is formed by bending a flat plate member, and includes a mount support portion 15a to which a mount member 16 that is connected to the cabin 2 is attached, as well as a front wall portion 15b and a rear wall portion 15c that extend downward at a distance from each other from the front and rear ends of the mount support portion 15a and are joined to the outer side surface of the side member 11 in the vehicle width direction. As a result, the mount bracket 15 is formed in a box shape that is open to the outer side and downward in the vehicle width direction.

The bumper frame 17 has a lower buffer member 21, an upper buffer member 23, and a fixing bracket 25, and is located at the front end of the chassis 3. The front side of the bumper frame 17 is covered by a resin bumper (not shown) provided at the front end of the vehicle 1.
The lower buffer member 21 is a buffer member that extends in the vehicle width direction and is fixed to the front end 11a of the side member 11 by, for example, bolts. The lower buffer member 21 extends from the position where it is fixed to the front end 11a of the side member 11 to the outside in the vehicle width direction, and an end (extension) 21a is bent so as to incline toward the rear. The upper buffer member 23 is a buffer member that extends in the vehicle width direction and is located above the lower buffer member 21. The upper buffer member 23 is bent so that an end on the outside in the vehicle width direction is inclined toward the rear. The upper buffer member 23 is fixed to the lower buffer member 21 by a plurality of fixing brackets 35 that extend in the vehicle up-down direction.

Therefore, when a load is applied from the front to the rear of the vehicle, such as in a frontal collision of the vehicle 1, the entire bumper frame 17 can bear the load applied from the front of the side member 11 and above it to the rear.
The lower cross member 19 is a frame member extending in the vehicle width direction and located below the side members 11 and between the suspension frame 13 and the bumper frame 17. By providing this lower cross member 19, the chassis 3 can suppress relative rocking of the pair of left and right side members 11 and increase the rigidity of the chassis, similar to the multiple cross member members (not shown) provided on the side members 11. In addition, the lower cross member 19 is provided with a deformation hole (rigidity reducing portion) 19a extending in the up-down direction at the center in the vehicle width direction.

Here, a pillar member 31 , an extension member 33 and a guide member 35 are disposed near the left and right ends of the lower cross member 19 .
The pillar members 31 are framework members extending downward from positions between the front wall portion 15b and the rear wall portion 15c of the mount bracket 15 in each of the left and right side members 11. The lower ends of the pillar members 31 are, for example, welded to both left and right ends of the lower cross member 19. Therefore, the lower cross member 19 is supported below the mount bracket 15 so as to be suspended at both left and right ends by the pillar members 31.

According to Figure 4, the extension members 33 are a pair of left and right members that are located between the front wall portion 15b and the rear wall portion 15c of the mount bracket 15, are joined to the extensions 12 of the side member 11 via the upper ends of the pillar members 31, and extend outward in the left-right direction.
The extension member 33 is located rearward of the bumper frame 17 in the vehicle front-rear direction (inner side in the vehicle front-rear direction), more specifically, rearward of the lower buffer member 21 and spaced a predetermined distance rearward of the guide member 35. The extension member 33 extends inclined, for example, 30° toward the vehicle front relative to the lower cross member 19 when viewed from the vehicle up-down direction, and is formed to extend from a portion spaced a certain distance from the side member 11 inclined, for example, 10° toward the vehicle front relative to the lower cross member 19.

As a result, the mount bracket 15 firmly supports the extension member 33, while the extension member 33 being provided on the mount bracket 15 also increases the rigidity of the mount bracket 15. Furthermore, since the extension member 33 is located on the front side of the mount bracket 15 in the vehicle longitudinal direction, when another vehicle 100 (described later) collides with the vehicle 1 from the front in the vehicle longitudinal direction, the extension member 33 receives the load from the other vehicle 100 before the mount bracket 15, thereby reducing the load applied to the mount bracket 15. Furthermore, since the mount bracket 15 is disposed on the extension 12, movement of the extension member 33 due to deformation of the extension 12 can be appropriately tolerated.

The guide member 35 is a flat plate member disposed in a position on the lower buffer member 21 of the bumper frame 17 corresponding to the front of the extension member 33, i.e., at the end 21a of the lower buffer member 21. When the guide member 35 comes into contact with the extension member 33 in the event of a frontal collision of the vehicle 1 described below and moves a predetermined distance rearward, it can press the extension member 33 rearward while preventing the extension member 33 from piercing the lower buffer member 21.

Next, the deformation and effect of the front of the chassis 3 when another vehicle (collided body) 100 collides from the front of the vehicle 1 will be described. Hereinafter, a case in which the other vehicle 100 collides with the entire left-right side of the bumper frame 17 as shown in Figure 5 will be referred to as a "full overlap collision," and a case in which the other vehicle 100 collides from the center to the left side of the bumper frame 17 as shown in Figures 6 to 8 will be referred to as an "offset collision."

Referring to Figure 5, there is shown an explanatory diagram illustrating the deformation of the front of the chassis 3 when another vehicle 100 collides with the vehicle 1 from the front in a full overlap manner. When another vehicle 100 collides with the front of the vehicle 1 in a full overlap manner and a load is applied uniformly in the vehicle width direction to the bumper frame 17, the buffer area C is crushed and contracted in the front-to-rear direction of the vehicle. Here, the buffer area C corresponds to the portion from the front end 11a of the side member 11 in the chassis 3 to the front cross member member 13a of the suspension frame 13. In other words, the buffer area C includes the extension 12.

When another vehicle 100 collides with the front portion of the bumper frame 17 and a predetermined load is applied to the left and right extensions 12, the left and right extensions 12 are crushed backward.
As a result, in the event of a full overlap collision, vehicle 1 collides with other vehicle 100 on the entire width of the vehicle via the bumper frame 17, thereby preventing the rigidity of vehicle 1 from becoming locally high, and ultimately preventing localized high loads from being applied to the other vehicle 100.

In addition, since the extension member 33 supports both the left and right sides of the bumper frame 17, when the extension 12 is crushed, it presses the bumper frame 17 so that the load is applied equally to the left and right, and the extension 12 can be crushed equally on the left and right sides.
In particular, since the lower cross member 19 is supported by the pillar members 31, it can swing rearward about the upper ends of the pillar members 31 as an axis, and thus can absorb impact while reducing the increase in rigidity of the buffer section C caused by the lower cross member 19. Furthermore, since the extension member 33 has a lower rigidity than the lower cross member 19, it can absorb impact while effectively reducing the increase in rigidity of the buffer section C caused by the extension member 33 when the front cross member 13a is crushed.

Referring to Figures 6 to 8, there are shown explanatory diagrams that explain the deformation of the front of the chassis 3 when another vehicle 100 offset collides from the front of the vehicle 1. When another vehicle 100 offset collides from the front of the vehicle 1 and a load is applied rearward from the center in the vehicle width direction to the left side of the bumper frame 17, the left side of the center in the left-right direction of the buffer range C is crushed and compressed in the fore-and-aft direction of the vehicle as shown in the order of Figures 6 to 8.

Specifically, first, the front contraction portion 12b mainly collapses (see FIG. 6). At this time, the extension member 33 comes into contact with the guide member 35 arranged on the bumper frame 17 that has moved a predetermined distance rearward in the vehicle longitudinal direction, and is pressed rearward. As a result, when the extension 12 collapses, the extension member 33 presses the bumper frame 17 to support it, thereby reducing the local increase in rigidity at the position corresponding to the extension 12.

In addition, when the extension member 33 is pressed rearward in this manner, a rotational force is generated in the lower cross member 19, with the pillar member 31 as an axis, pressing the vicinity of the deformation hole 19a forward. Therefore, the force with which the other vehicle 100 presses the vehicle 1 rearward can be used to move the vicinity of the deformation hole 19a of the lower cross member 19 forward, so that the center of the lower cross member 19 in the vehicle width direction can be brought into contact with the other vehicle 100 via the bumper frame 17 at an early stage.

In addition, in the event of an offset collision with another vehicle 100 from the front of the vehicle 1, the lower cross member 19 bends near the deformation hole 19a, so that the impact can be absorbed not only by the extension 12 but also by absorbing the impact when the lower cross member 19 is bent. Furthermore, since the lower cross member 19 has the deformation hole 19a formed therein, it can bend near the deformation hole 19a, and therefore can come into contact with the other vehicle 100 sooner than, for example, when a lower cross member without the deformation hole 19a is used.

When the other vehicle 100 continues to travel toward the vehicle 1, the lower cross member 19 is bent at the deformation hole 19a (see FIGS. 7 and 8). The lower cross member 19 bent at the deformation hole 19a in this manner is pressed rearward by the other vehicle 100 in the vicinity of the deformation hole 19a. At this time, a force is generated in the extension member 33 in the rotational direction, which presses the left end forward with the pillar member 31 as an axis.
As a result, as the portion of the left lower cross member 19 near the deformation hole 19a is pressed rearward by the other vehicle 100, the extension member 33 can be pressed toward the front of the vehicle like a lever, so that the left side of the bumper frame 17 can be pressed against the other vehicle 100.

Therefore, even if the right extension 12 does not collapse due to an offset collision and the left extension 12 alone is insufficient to absorb the impact, resulting in lower cushioning compared to a full overlap collision, the lower cross member 19 can be deformed to bend and the extension member 33 can press the left side of the bumper frame 17 against the other vehicle 100, thereby increasing the rigidity of the left side of the cushioning range C and ensuring cushioning equivalent to that of a full overlap collision.

In particular, by utilizing the force of the other vehicle 100 pressing the vehicle 1 rearward, the center and left end of the bumper frame 17 in the vehicle width direction are pressed toward the front of the vehicle via the lower cross member 19 and the extension member 33, the rigidity of the entire bumper frame 17 can be made uniform, and ultimately the occurrence of localized loads applied to the other vehicle 100 can be reduced.
As described above, the chassis frame structure of the present invention is a chassis frame structure that supports the cabin 2, which is part of the body of the vehicle 1, and includes a pair of left and right side members 11 extending in the fore-and-aft direction of the vehicle, a bumper frame 17 that is provided on the outer side of the side members 11 in the fore-and-aft direction of the vehicle, i.e., at the front end 11a on the front side of the side members 11, extending in the vehicle width direction, and has an end portion 21a that extends outward in the vehicle width direction beyond the side members 11, and a front cross member member 13a that is provided between the side members 11 and extends in the vehicle width direction.

The chassis frame structure according to the present invention also includes a mount bracket 15 that is provided between the bumper frame 17 of the side member 11 and the front cross member member 13a and supports the cabin 2, and an extension member 33 that extends outward in the vehicle width direction from the position where the mount bracket 15 of the side member 11 is provided, and extends to a position facing the end 21a of the bumper frame 17 on the inner side in the vehicle longitudinal direction.

Therefore, the extension 12, which is formed in the area from the bumper frame 17 of the side member 11 to the front cross member member 13a and which collapses in the vehicle longitudinal direction when a certain load is applied, is provided with a mount bracket 15 and an extension member 33 that extends outward in the vehicle width direction from the mount bracket 15 and is located on the rear side of the bumper frame 17 in the vehicle longitudinal direction. This allows the extension member 33 to be firmly supported by the mount bracket 15 while allowing an appropriate amount of movement of the extension member 33 due to deformation of the extension 12. Furthermore, by providing the extension member 33 to the mount bracket 15, the rigidity of the mount bracket 15 can also be increased.

Furthermore, the extension member 33 extends outward in the vehicle width direction from the mounting bracket 15 of the side member 11 to a position facing the inner side of the end 21a of the bumper frame 17 in the vehicle longitudinal direction, i.e., it is located in front of the mounting bracket 15 in the vehicle longitudinal direction. Therefore, when another vehicle 100 collides with the vehicle 1 from the outside in the vehicle longitudinal direction, the extension member 33 receives the load from the other vehicle 100 before the mounting bracket 15, thereby reducing the load applied to the mounting bracket 15.

The side member 11 has an extension 12 between the bumper frame 11 and the front cross member member 13 that buckles to absorb impact when a load of a predetermined magnitude or more is applied in the fore-and-aft direction of the vehicle. For example, when the entire bumper frame 17 receives an impact, such as in a full overlap collision, the bumper frame 17 is supported so that the load is applied evenly to the left and right extensions 12, and the left and right extensions 12 can be crushed equally. When the bumper frame 17 receives an impact biased to one side in the vehicle width direction, such as in an offset collision, the extension member 33 supports the bumper frame 17, reducing the local increase in rigidity at the position corresponding to the extension 12.

Furthermore, the extension member 33 is designed to support the bumper frame 17 at least when the bumper frame 17 moves rearward in the vehicle's fore-and-aft direction by a predetermined distance or more, so that the bumper frame 17 can be supported by the extension member 33 in the event of a relatively large collision in which the bumper frame 17 moves by more than a predetermined distance.
The mount bracket 15 has a mount support portion 15a to which a mount member 16 connected to the cabin 2 is attached, and a front wall portion 15b and a rear wall portion 15c which extend downwardly with a gap between them from the front and rear of the mount support portion 15a and are joined to the outer side surface of the side member 11 in the vehicle width direction.The extension member 33 extends from the side member 11 between the front wall portion 15b and the rear wall portion 15c, thereby increasing the strength of the portion of the side member 11 from which the pillar member 31 extends.

Furthermore, the lower cross member 19 is provided at a position where the mount bracket 15 is located between the front cross member member 13a and the bumper frame 17 in the fore-and-aft direction of the vehicle and extends in the vehicle width direction, so that the force pressing the lower cross member 19 rearward in the fore-and-aft direction of the vehicle can be utilized to press the extension member 33 forward in the fore-and-aft direction of the vehicle.
The lower cross member 19 is provided with a pillar member 31 extending downward from the position where the mounting bracket 15 of the side member 11 is provided, and is positioned below the side member 11 and has its left and right ends supported by the pillar member 31. The pillar member 31 is joined to the side of the side member 11 between the front wall portion 15b and the rear wall portion 15c of the mounting bracket 15, and the extension member 33 is joined to the side member 11 via the pillar member 31 between the front wall portion 15b and the rear wall portion 15c of the mounting bracket 15. Therefore, while allowing the lower cross member 19 to swing, the force applied to the lower cross member 19 when the extension 12 collapses can be transmitted to the extension member 33 around the pillar member 31 as an axis.

Since the pillar member 31 extends downward from the rear side of the mount bracket 15, the strength of the portion of the side member 11 to which the pillar member 31 is attached can be increased.
Furthermore, a deformation hole 19a is formed in the center of the vehicle width direction in the lower cross member 19, which reduces the rigidity against bending forces in the fore-and-aft direction of the vehicle.Therefore, the force with which the deformation hole 19a of the lower cross member 19 is pressed toward the center in the fore-and-aft direction of the vehicle during a collision can be used to press the bumper frame 17 outward by the reinforcement portion.

This concludes the explanation of the chassis frame structure according to the present invention, but the present invention is not limited to the above embodiment and can be modified without departing from the spirit and scope of the invention.
For example, in this embodiment, the extension 12, bumper frame 17, lower cross member 19, etc. are arranged at the front of the vehicle 1, and the case where another vehicle 100 collides with the vehicle 1 from the front is described, but the rear of the vehicle 1 may be configured in a similar manner to prepare for the case where another vehicle 100 collides with the vehicle 1 from the rear.

In addition, in this embodiment, the lower cross member 19 is located below the side members 11, and the left and right ends are supported by pillar members 31 extending downward from the extensions 12 of the side members 11, and the extension members 33 are fixed to the lower cross member 19 via the pillar members 31 and the mount brackets 15. However, the lower cross member 19 may be fixed to the rear side of the left and right side members 11 in the vehicle width direction without using the pillar members 31. In this case, the extension members 33 may be fixed to the lower cross member 19 only via the mount brackets 15.

In addition, in this embodiment, the guide member 35 is spaced a certain distance behind the lower cushioning member 21, but it may be in contact with the end 21a of the lower cushioning member 21.

1 Vehicle 2 Cabin (body)
3 Chassis 11 Side member 11a Front end (end portion)
12 Extension (buffer section)
13a: Front cross member (first cross member)
15 Mount bracket 15a Mount support portion 15b Front wall portion 15c Rear wall portion 16 Mount member 17 Bumper frame 19 Lower cross member (second cross member)
19a Deformation hole (reduced rigidity portion)
19b Rear end (inner end)
21a End (extension)
31 Pillar member 33 Extension member 41 Outer member 43 Inner member 100 Another vehicle (collision target)

Claims (4)

A frame structure for a chassis that supports a body of a vehicle,
A pair of left and right side members extending in a front-rear direction of the vehicle;
a bumper frame provided at an outer end of the side member in the vehicle front-rear direction so as to extend in a vehicle width direction and having an extension portion extending outward in the vehicle width direction from the side member;
a first cross member provided between the side members and extending in a vehicle width direction;
a mount bracket provided between the bumper frame of the side member and the first cross member and supporting the body;
an extension member extending outward in a vehicle width direction from a position where the mount bracket of the side member is provided and extending to a position facing the extension portion of the bumper frame on an inner side in the vehicle front-rear direction;
a pillar member extending downward from a position of the side member where the mount bracket is provided;
a second cross member provided at a position where the mount bracket is provided between the first cross member and the bumper frame in a vehicle front-rear direction and extending in a vehicle width direction ,
the mount bracket has a mount support portion to which a mount member to be connected to the body is attached, and a front wall portion and a rear wall portion extending downward from the front and rear of the mount support portion with a space between them and joined to a side surface of the side member on an outer side in the vehicle width direction,
the extension member extends from the side member between the front wall portion and the rear wall portion,
the second cross member is located below the side members and has left and right ends supported by the pillar members,
the pillar member is joined to a side surface of the side member between the front wall portion and the rear wall portion of the mounting bracket,
The extension member is joined to the side member via the pillar member between the front wall portion and the rear wall portion of the mount bracket.
A frame structure for a vehicle chassis. The chassis frame structure as described in claim 1, characterized in that a buffer portion is provided between the bumper frame of the side member and the first cross member, which buckles to absorb impact when a load of a predetermined magnitude or more is applied in the fore-and-aft direction of the vehicle. 3. The frame structure according to claim 1, wherein the extension member supports the bumper frame at least when the bumper frame moves inward in the vehicle front-rear direction by a predetermined distance or more. 2. The chassis frame structure according to claim 1 , wherein the second cross member is formed with a rigidity reducing portion at a center in a vehicle width direction, the rigidity reducing portion reducing rigidity against bending forces in a vehicle front-rear direction.

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