JP7708558B2 - Vehicle frame structure - Google Patents

Description

This disclosure relates to a vehicle frame structure.

As an example of technology relating to a frame structure for a vehicle that runs on power supplied from a battery, there is a frame structure described in Patent Document 1. This conventional frame structure includes a ladder frame in which a pair of side rails are provided facing each other in the vehicle width direction, and a power supply unit that is disposed between the pair of side rails and connected to each of the side rails. Each of the pair of side rails is provided with a flange of a predetermined width on both ends of the web. The flange is provided with a narrowed portion at a position corresponding to at least one corner of the power supply unit in the vehicle width direction.

JP 2012-14208 A

In the conventional frame structure described above, the side rails are generally in a straight line. Therefore, in the event of a frontal collision, the side rails are subjected to axial compression, making the structure advantageous in terms of deformation. Meanwhile, in recent years, there has been a demand for lower vehicle floors in order to ensure the vehicle's load capacity. In response to this demand, a frame configuration is being considered in which the side rails are provided with upper and lower kick sections, lowering the rear portion of the frame located below the loading platform by one step relative to the front portion of the frame located below the cab.

However, in a configuration in which upper and lower kick sections are provided on a frame, there is an issue that the upper and lower kick sections tend to lack rigidity, making them prone to deformation or damage in the event of a frontal collision of the vehicle. It is possible to reinforce the upper and lower kick sections by adding separate members such as reinforcing parts, but in this case, the increase in the number of parts will lead to a more complicated configuration and a heavier vehicle.

This disclosure has been made to solve the above problems, and aims to provide a vehicle frame structure that can suppress deformation and damage to the upper and lower kick sections in a frontal collision while avoiding an increase in complexity and weight of the structure.

The vehicle frame structure according to one aspect of the present disclosure is a vehicle frame structure having a pair of left and right side rails extending in the fore-and-aft direction of the vehicle, the side rails having a front side rail located at the front of the vehicle and supporting the front wheels and the cab, a rear side rail located behind the front side rail and supporting the rear wheels and the cargo bed, and upper and lower kick sections that connect the rear side rail one step lower than the front side rail, and a notch is provided in the front portion of the front side rail in the width direction of the vehicle.

In this vehicle frame structure, a notch is provided in the forward portion of the front side rail in the width direction of the vehicle. This notch makes it easier for the portion of the front side rail forward of the notch to be crushed in the event of a frontal collision of the vehicle, improving the efficiency of impact absorption. This makes it possible to suppress deformation and damage to the upper and lower kick parts in the event of a frontal collision while avoiding the need to add additional components such as reinforcing parts to complicate the structure and increase its weight.

The front side rail is a hollow member with a rectangular cross section formed by combining an outer rail located on the outside in the vehicle's width direction with an inner rail located on the inside in the vehicle's width direction, and the cutout may be formed in a corner of the inner rail. By forming the cutout in the corner of the inner rail, it is possible to ensure both the rigidity of the front side rail and its ease of crushing in the event of a front collision. It is also possible to prevent the portion that is crushed in a front collision from spreading outward in the vehicle's width direction. This makes it possible to prevent a decrease in the efficiency of impact absorption.

The upper surface of the inner rail may be provided with a flange portion that extends across the notch in the fore-and-aft direction of the vehicle. This prevents the portion that is crushed in a frontal collision from spreading upward on the vehicle. This reduces the impact of a collision on the cab, which is located above the front side rail.

The vehicle may further include a first cross member that is provided in the width direction of the vehicle to connect the portions of the front side rails that are rearward of the cutouts. The arrangement of this first cross member can prevent the front side rails from expanding in the width direction of the vehicle due to a frontal collision. This allows the portions of the front side rails forward of the cutouts to be crushed more efficiently during a frontal collision, further increasing the efficiency of impact absorption.

The vehicle may further include a suspension member that connects the portion of the front side rail rearward of the notch with the forward portion of the rear side rail. In this case, the collision energy applied to the front side rail during a front collision can be dispersed to the rear side rail via the suspension member. This makes it possible to more reliably prevent deformation and damage to the upper and lower kick portions. In addition, since the front side rail can be prevented from spreading upwards in the event of a front collision, the impact of a collision on the cab located above the front side rail can be more reliably mitigated.

The rear side rail has a wide section adjacent to the upper and lower kick sections, in which the frame width is increased by making the rail spacing larger than that of the front side rail. The wide section includes a front portion of the rear side rail and a second cross member that is provided in the width direction of the vehicle so as to connect the tips of the front portions of the rear side rail, and the suspension member may be connected to the front portion of the rear side rail via the second cross member.

Such a wide portion contributes to both ensuring space for arranging a battery, etc., when the vehicle is an electric vehicle, and ensuring load capacity by lowering the vehicle's floor. On the other hand, by connecting the suspension member to the front portion of the rear side rail via the second cross member that constitutes the wide portion, deformation or damage to the second cross member in the event of a frontal collision can be suppressed. This helps protect vehicle objects within the arrangement space.

This disclosure makes it possible to suppress deformation and damage to the upper and lower kick parts in a frontal collision while avoiding an increase in complexity and weight of the structure.

1 is a plan view showing a main portion of a vehicle frame structure according to an embodiment of the present disclosure. FIG. FIG. 2 is a side view of FIG. 1 . FIG. 2 is a perspective view showing the configuration of a front portion of a front side rail.

Below, a preferred embodiment of a vehicle frame structure according to one aspect of the present disclosure will be described in detail with reference to the drawings.

Figure 1 is a plan view showing a main part of a frame structure of a vehicle according to an embodiment of the present disclosure. Also, Figure 2 is a side view of Figure 1. The frame structure 1 of the vehicle shown in Figures 1 and 2 is a structure applied to a large vehicle such as a truck, and has a ladder frame structure. The vehicle may be, for example, an electric vehicle that runs by driving a motor with battery power.

The vehicle frame structure 1 is composed of a pair of left and right side rails 2, 2 that extend in the front-rear direction of the vehicle, and multiple cross members 3, 4, 5 that extend in the width direction of the vehicle and connect the side rails 2, 2 to each other. The side rails 2, 2 and the cross members 3, 4, 5 are all composed of long metal members.

The side rails 2, 2 are shaped and positioned approximately symmetrically on the left and right. The side rail 2 has a front side rail 11 located at the front of the vehicle and supporting the front wheels 6 and the cab 7, a rear side rail 12 located behind the front side rail 11 and supporting the rear wheels (not shown) and the cargo bed 8, and upper and lower kick sections 13 that connect the rear side rail 12 one step lower than the front side rail 11. The side rail 2 is also provided with a suspension member 9 that supports the front wheels 6 by a suspension device such as a leaf spring.

The tips of the front portions 11a, 11a of the front side rail 11 are connected by a cross member 3. The front portions 11a, 11a of the front side rail 11 are also connected by a cross member (first cross member) 4 behind the cross member 3. Various parts such as the vehicle motor, inverter, and gears are arranged in the space between the left and right front side rails 11, 11.

The rear side rail 12 has a wide section K in which the rail spacing is made larger than the rail spacing of the front side rails 11, 11 to increase the frame width. In this embodiment, the wide section K is provided adjacent to the upper and lower kick sections 13 by the front sections 12a, 12a of the left and right rear side rails 12, a cross member 5 (second cross member) connecting the tips of the front sections 12a, 12a of the rear side rails 12, and a cross member (not shown) connecting the tips of the rear sections of the rear side rails 12, 12 rearward of the cross member 5. The wide section K has a rectangular shape in a plan view. For example, a high-voltage battery that serves as a power source for the vehicle is arranged in the space inside the wide section K.

The upper and lower kick sections 13 slope gently downward, continuing from the rear portion 11b of the front side rail 11, and are connected to the cross member 5 of the wide portion K. That is, the upper and lower kick sections 13 are connected to the front portion 12a of the rear side rail 12 via the cross member 5 of the wide portion K. The upper and lower kick sections 13 lower the rear side rail 12 by one step relative to the front side rail 11, making it possible to lower the position of the cargo bed 8. This ensures the vehicle's load capacity.

The suspension member 9 is disposed at the height of the rear side rail 12 and extends in the front-to-rear direction of the vehicle, slightly inside the vehicle width direction of the front side rail 11. The front portion 9a of the suspension member 9 extends outward in the vehicle width direction toward the front side rail 11, and the tip of the front portion 9a is connected to the front portion 11a of the front side rail 11 by an anchor. The rear portion 9b of the suspension member 9 is suspended from the rear portion 11b of the front side rail 11 and is connected to the cross member 5 of the wide portion K. In other words, the rear portion 9b of the suspension member 9 is connected to the front portion 12a of the rear side rail 12 via the cross member 5 of the wide portion K.

Next, the configuration of the above-mentioned front side rail 11 will be described in more detail. Figure 3 is a perspective view showing the configuration of the front part of the front side rail. As shown in the figure, the front side rail 11 is formed by joining an outer rail 21 located on the outside in the vehicle width direction and an inner rail 22 located on the inside in the vehicle width direction.

The outer rail 21 has a side plate 23 and flanges 24, 25 provided at the upper and lower ends of the side plate 23, forming a C-shaped cross section. The inner rail 22, like the outer rail 21, has a side plate 26 and flanges 27, 28 provided at the upper and lower ends of the side plate 26, forming a C-shaped cross section. The front side rail 11 is formed by overlapping the flanges 27, 28 of the inner rail 22 on the flanges 24, 25 of the outer rail 21 and joining them together, forming a hollow member with a rectangular cross section.

The front portion 11a of the front side rail 11 has a notch 30 in the width direction of the vehicle. The notch 30 is formed at a corner of the inner rail 22 at a fixed distance from the tip of the front side rail 11. In the example of FIG. 3, rectangular notches 30, 30 are provided at both the corner 22a between the side plate 26 and the upper flange portion 27 and the corner 22b between the side plate 26 and the lower flange portion 28. At the position of the notch 30, the internal space of the front side rail 11 is exposed from the inner rail 22 side. The positions of the two notches 30, 30 in the front-rear direction of the vehicle are equal to each other. The widths of the two notches 30, 30 in the front-rear direction of the vehicle are also equal to each other.

The flange portion 27 on the upper surface of the inner rail 22 extends in the front-rear direction of the vehicle, straddling the notch 30. More specifically, this flange portion 27 extends from the tip of the front side rail 11 beyond the notch 30. The width of the flange portion 27 gradually decreases rearward from the notch 30. In the rear portion where the flange portion 27 is not present, the inner rail 22 is composed only of the side plate 26 and the flange portion 28 on the lower surface. Therefore, rearward of the notch 30, the upper surface of the front side rail 11 is formed only by the flange portion 24 on the upper surface of the outer rail 21.

As shown in Figs. 1 and 2, the cross member 4 is provided in the width direction of the vehicle so as to connect the portions of the front side rail 11 rearward of the notch 30. Furthermore, in this embodiment, the connection position P1 between the front portion 9a of the suspension member 9 and the front portion 11a of the front side rail 11 coincides with the connection position P2 between the front side rail 11 and the cross member 4. The notch 30 and the connection positions P1 and P2 may be adjacent to each other or may be spaced apart by a certain distance.

As described above, in the vehicle frame structure 1, the front portion 11a of the front side rail 11 is provided with a notch 30 in the width direction of the vehicle. This notch 30 makes it easier for the portion of the front side rail 11 forward of the notch 30 to be crushed in the event of a frontal collision of the vehicle, improving the efficiency of impact absorption. Therefore, it is possible to suppress deformation and damage of the upper and lower kick portions 13 in the event of a frontal collision while avoiding the complication and weight increase of the configuration due to the addition of separate members such as reinforcing parts.

In this embodiment, the front side rail 11 is a hollow member with a rectangular cross section, formed by combining an outer rail 21 located on the outside in the vehicle's width direction and an inner rail 22 located on the inside in the vehicle's width direction. The notches 30 are formed in the corners 22a, 22a of the inner rail 22. By forming the notches 30 in the corners 22a, 22a of the inner rail 22 in this way, it is possible to ensure both the rigidity of the front side rail 11 and its ease of crushing during a front collision. In addition, it is possible to prevent the portion that is crushed during a front collision from spreading outward in the vehicle's width direction. This makes it possible to prevent a decrease in the efficiency of impact absorption.

In this embodiment, a flange portion 27 is provided on the upper surface of the inner rail 22, straddling the notch 30 and extending in the fore-and-aft direction of the vehicle. This makes it possible to prevent the portion that is crushed in a frontal collision from spreading upward on the vehicle. Therefore, the impact of a collision on the cab 7, which is located above the front side rail 11, can be mitigated.

In this embodiment, a cross member 4 is provided in the width direction of the vehicle to connect the portions of the front side rails 11 rearward of the cutouts 30. This arrangement of the cross member 4 can prevent the front side rails 11, 11 from expanding in the width direction of the vehicle due to a frontal collision. As a result, the portions of the front side rails 11 forward of the cutouts 30 are more efficiently crushed in the event of a frontal collision, further increasing the efficiency of impact absorption.

In this embodiment, a suspension member 9 is provided that connects the portion of the front side rail 11 rearward of the notch 30 to the front portion 12a of the rear side rail 12. This allows the collision energy applied to the front side rail 11 during a front collision to be dispersed to the rear side rail 12 via the suspension member 9. This makes it possible to more reliably prevent deformation and damage to the upper and lower kick portions 13. In addition, since the front side rail 11 can be prevented from spreading upwards of the vehicle during a front collision, the impact of a collision on the cab 7 located above the front side rail 11 can be more reliably mitigated.

In this embodiment, the rear side rail 12 has a wide section K adjacent to the upper and lower kick sections 13, in which the rail spacing is made larger than the rail spacing of the front side rails 11, 11 to increase the frame width. The suspension member 9 is connected to the front portion 12a of the rear side rail 12 via the cross member 5 of the wide section K. The wide section K contributes to both ensuring space for arranging a battery, etc., when the vehicle is an electric vehicle, and ensuring the load capacity by lowering the vehicle floor. On the other hand, by connecting the suspension member 9 to the front portion 12a of the rear side rail 12 via the cross member 5 constituting the wide section K, deformation or damage of the cross member 5 in the event of a frontal collision can be suppressed. This provides protection for vehicle objects in the arrangement space.

The present disclosure is not limited to the above embodiment. For example, in the above embodiment, the front portion 11a of the front side rail 11 has the notch 30 on the inner rail 22 side, but the notch 30 may also be provided on the outer rail 21 side. The notch 30 does not necessarily have to be provided on both corners 22a, 22b, but may be provided on only one of the corners 22a, 22b. The notch 30 may be provided on the side plate 26 instead of the corners 22a, 22b. The front side rail 11 does not necessarily have to be composed of the outer rail 21 and the inner rail 22, but may be composed of a single hollow member.

The connection position P1 between the front portion 9a of the suspension member 9 and the front portion 11a of the front side rail 11 does not necessarily have to coincide with the connection position P2 between the front side rail 11 and the cross member 4. For example, the connection position P1 between the front portion 9a of the suspension member 9 and the front portion 9a of the front side rail 11 may be located rearward of the connection position P2 between the front side rail 11 and the cross member 4.

1...vehicle frame structure, 2...side rail, 4...cross member (first cross member), 5...cross member (second cross member), 6...front wheel, 7...cab, 8...cargo bed, 9...suspension member, 11...front side rail, 11a...front portion, 12...rear side rail, 12a...front portion, 13...upper and lower kick portions, 21...outer rail, 22...inner rail, 22a, 22b...corner portion, 27...flange portion, 30...notch portion, K...wide portion.

Claims (9)

A frame structure of a vehicle having a pair of left and right side rails extending in a front-rear direction of the vehicle,
The side rails include:
a front side rail located at a front side of the vehicle and supporting a front wheel and a cab;
a rear side rail located rearward of the front side rail and supporting a rear wheel and a cargo bed;
and an upper and lower kick portion that connects the rear side rail to a lower level relative to the front side rail,
A notch is provided in a front portion of the front side rail in a width direction of the vehicle,
the front side rail is a hollow member having a rectangular cross section formed by combining an outer rail located on the outer side in a width direction of the vehicle and an inner rail located on the inner side in the width direction of the vehicle,
The cutout portion is formed at a corner portion of the inner rail,
A vehicle frame structure in which a flange portion extending in the fore-and-aft direction of the vehicle is provided on an upper surface side of the inner rail, straddling the cutout portion . The vehicle frame structure according to claim 1, further comprising a first cross member arranged in the width direction of the vehicle to connect the portions of the front side rails rearward of the cutouts. The vehicle frame structure according to claim 1 or 2, further comprising a suspension member that connects a portion of the front side rail rearward of the notch and a front portion of the rear side rail. The rear side rail has a rail spacing greater than that of the front side rail, thereby forming a wide portion adjacent to the upper and lower kick portions, and the wide portion has a frame width greater than that of the front side rail.
the wide portion includes a front portion of the rear side rail and a second cross member provided in a width direction of the vehicle so as to connect tips of the front portions of the rear side rails together,
4. The vehicle frame structure according to claim 3, wherein the suspension member is connected to a front portion of the rear side rail via the second cross member. A frame structure of a vehicle having a pair of left and right side rails extending in a front-rear direction of the vehicle,
The side rails include:
a front side rail located at a front side of the vehicle and supporting a front wheel and a cab;
a rear side rail located rearward of the front side rail and supporting a rear wheel and a cargo bed;
and an upper and lower kick portion that connects the rear side rail to a lower level relative to the front side rail,
A notch is provided in a front portion of the front side rail in a width direction of the vehicle,
A vehicle frame structure further comprising a suspension member connecting a portion of the front side rail rearward of the cutout portion and a front portion of the rear side rail. The rear side rail has a rail spacing greater than that of the front side rail, thereby forming a wide portion adjacent to the upper and lower kick portions, and the wide portion has a frame width greater than that of the front side rail.
the wide portion includes a front portion of the rear side rail and a second cross member provided in a width direction of the vehicle so as to connect tips of the front portions of the rear side rails together,
6. The vehicle frame structure according to claim 5, wherein the suspension member is connected to a front portion of the rear side rail via the second cross member. The front side rail includes an outer rail located on an outer side in a width direction of the vehicle,
The inner rail is connected to the inner side of the vehicle in the width direction to form a hollow member having a rectangular cross section.
7. The vehicle frame structure according to claim 5, wherein the cutout portion is formed at a corner portion of the inner rail. The vehicle frame structure according to claim 7, wherein a flange portion is provided on the upper surface side of the inner rail, straddling the notch and extending in the fore-and-aft direction of the vehicle. 8. A vehicle frame structure according to claim 5, further comprising a first cross member provided in the width direction of the vehicle so as to connect portions of the front side rails rearward of the cutout portions.