JP7803255B2 - Vehicle undercarriage - Google Patents

Description

The present invention relates to a vehicle undercarriage in which a slide rail for a sliding door is connected to the arm portion of the sliding door and is provided under a rocker that forms the lower edge of the door opening.

Related technology is described in Patent Document 1. In the vehicle of Patent Document 1, a door opening provided in the vehicle body is configured to be able to be opened and closed in the fore-and-aft direction of the vehicle by a sliding door. A cylindrical side sill, which corresponds to the locker of the present application, is provided at the lower edge of this door opening and extends in the fore-and-aft direction of the vehicle. In addition, a battery case is disposed as an internal component under the floor of the vehicle, and this battery case is positioned inside the side sill in the vehicle width direction so as to fit along the side sill.

A slide rail that supports the sliding door so that it can slide is provided inside the side sill, extending in the fore-and-aft direction of the vehicle. A portion of the side sill (cross-sectional shape) is formed into a concave shape that opens outward in the vehicle width direction, and the slide rail is fixed to this concave portion. Furthermore, an arm portion is provided at the lower end of the sliding door so that it protrudes inward in the vehicle width direction, and a roller journaled on this arm portion is slidably fitted into the slide rail. This allows the sliding door to slide in the fore-and-aft direction of the vehicle by sliding the roller along the slide rail.

Japanese Patent Application Laid-Open No. 2019-18822

In the above-mentioned vehicle, there is a demand for placing the slide rail under the rocker. That is, by placing the slide rail under the rocker, the freedom of rocker shape selection is increased, making it easier to ensure the rocker's rigidity. Furthermore, by ensuring the rocker's rigidity, the vehicle's vertical dimensions can be made more compact, making it easier to ensure the rocker's ground clearance (height from the ground). However, when the slide rail is placed under the rocker as described above, the arm portion of the sliding door connected to the slide rail protrudes inward in the vehicle width direction, i.e., toward the internal components. Therefore, with the above-mentioned configuration, care must be taken to prevent the arm portion, when subjected to an impact load during a vehicle collision, from moving inward in the vehicle width direction and striking the internal components with force. The present invention was devised in light of the above points, and the problem it aims to solve is to prevent the arm portion under the rocker from striking the internal components under the floor with force during a vehicle collision, etc.

As a means for solving the above problems, a vehicle undercarriage of a first invention includes a sliding door that opens and closes a door opening in a vehicle body, and a cylindrical locker that forms the lower edge of the door opening. A slide rail that supports the sliding door so that it can slide in an opening and closing direction is provided on the vehicle underside of the locker and is connected to the arm portion of the sliding door. When a direction perpendicular to the opening and closing direction is defined as the vehicle interior/exterior direction in a plan view in the vehicle's vertical direction, the arm portion extends inward toward an internal component disposed under the vehicle floor. In this type of configuration, it is desirable to prevent the arm portion under the rocker from strongly hitting the internal component under the floor during a vehicle collision or the like. Therefore, the vehicle undercarriage of the present invention includes a moving structure that moves the vehicle-inboard end of the arm portion, when an impact load is applied, in a direction intersecting the vehicle interior/exterior direction. In this invention, when an impact load is applied to the arm portion from outside the vehicle, the moving structure functions to move the vehicle-inboard end of the arm portion in a direction intersecting the vehicle interior/exterior direction, i.e., in a direction away from the internal component. This makes it less likely that the arm portion to which an impact load is applied will come into strong contact with the internal member.
Furthermore, the vehicle undercarriage of the first invention is the vehicle undercarriage of the first invention, and the moving structure includes a receiving member provided at a position capable of receiving the vehicle-inner end of the arm portion to which an impact load is applied. In this invention, the arm portion to which an impact load is applied is received by the receiving member and is less likely to move toward the vehicle inward, so that the arm portion bends and deforms in a direction different from the vehicle inward/outward direction. Then, the bending and deformation of the arm portion to which the impact load is applied allows the vehicle-inward end of the arm portion to move in a direction intersecting the vehicle inward/outward direction.

The vehicle undercarriage of the second invention is the vehicle undercarriage of the first invention, but is provided with a moving structure that moves the end of the arm portion on the inside of the vehicle to which an impact load is applied, toward the upper or lower side of the internal member. In this invention, the moving structure allows the end of the arm portion on the inside of the vehicle to be moved toward the upper or lower side of the internal member.

The vehicle undercarriage of the third invention is the vehicle undercarriage of the first invention, wherein the receiving member has a receiving portion that can receive the vehicle-inside end of the arm portion, and is provided between the arm portion and the internal member in the vehicle inside-outside direction. In this invention, when an impact load is applied to the arm portion, the vehicle-inside end of the arm portion can be received by the receiving portion of the receiving member before it reaches the internal member.

The vehicle undercarriage of the fourth invention is the vehicle undercarriage of the first or third invention, and further includes a protruding portion as a moving structure, in which a portion of the arm portion protrudes outward from the fixed portion of the arm portion to the sliding door. In this invention, the arm portion provided at this protruding portion is more reliably bent and deformed by receiving an impact load at the protruding portion. Furthermore, by increasing the length of the arm portion at the protruding portion to ensure excess length, the arm portion is more reliably bent and deformed.

The vehicle understructure of the fifth invention is the vehicle understructure of the first or third invention , in which a weak portion is provided as a moving structure to promote deformation of the arm portion in a direction intersecting the vehicle interior/exterior direction. In this invention, the weak portion acts to allow the arm portion to bend and deform smoothly when an impact load is applied.

According to the first aspect of the present invention, it is possible to prevent the arm portion under the rocker from strongly hitting an internal component under the floor during a vehicle collision or the like. Also, according to the first aspect, it is possible to bend and deform the arm portion so that it does not strongly hit the internal component. Also, according to the second aspect, it is possible to more reliably prevent the arm portion from strongly hitting the internal component. Also, according to the third aspect, it is possible to more reliably bend and deform the arm portion. Also, according to the fourth aspect, it is possible to even more reliably bend and deform the arm portion. And according to the fifth aspect, it is possible to more smoothly bend and deform the arm portion.

FIG. 1 is a partial perspective side view of a vehicle showing a locker. 2 is a cross-sectional view of the lower part of the vehicle corresponding to the cross section of line II-II in FIG. 1. FIG. 1 is a perspective top view of a vehicle showing internal components. FIG. 2 is an enlarged perspective top view of the lower portion of the vehicle showing the slide rails. 5 is a cross-sectional view of the lower part of the vehicle corresponding to the cross section of line VV in FIG. 4. FIG. 2 is a cross-sectional view of the lower part of a vehicle at the beginning of a vehicle collision. FIG. 1 is a cross-sectional view of the underside of a vehicle at a later stage of a vehicle collision.

Embodiments of the present invention will be described below with reference to Figures 1 to 7. Arrows indicating the fore-and-aft direction, left-and-right direction (vehicle width direction), and up-and-down direction (vehicle height direction) of the vehicle are shown in each figure as appropriate. Note that in Figures 1 and 3, only components on the left side of the vehicle are designated with corresponding symbols. Furthermore, based on Figure 3 (plan view in the vehicle up-and-down direction), the fore-and-aft direction corresponds to the opening and closing direction of the sliding door, and the vehicle width direction perpendicular to the opening and closing direction corresponds to the vehicle inward-outward direction. In each figure, the left side, which is on the outside in the vehicle width direction, corresponds to the outside of the vehicle, and the right side, which is on the inside in the vehicle width direction, corresponds to the inside of the vehicle.

[Vehicle Overview]
Before describing the vehicle's undercarriage, an overview of a vehicle 2 shown in FIG. 1 will be described. A vehicle body 10 of the vehicle 2 has a front door opening 11 corresponding to the front seats and a rear door opening 12 corresponding to the rear seats. The front door opening 11 can be opened and closed by a front door 15 that can rotate about a door hinge (not shown). The rear door opening 12 can be opened and closed by a sliding door 20 that slides in the fore-and-aft direction of the vehicle. A rocker 30, which is a cylindrical frame, is provided at the lower edge of the rear door opening 12 so as to extend in the fore-and-aft direction of the vehicle. A center pillar 13 extending in the vertical direction of the vehicle is provided between the front door opening 11 and the rear door opening 12, and the lower end of the center pillar 13 is connected to the rocker 30.

The vehicle 2 shown in FIG. 1 also has multiple slide rails 17, 18, and 19 provided at appropriate positions to support the sliding door 20 so that it can slide in the fore-and-aft direction of the vehicle (opening and closing direction). For example, in the vehicle 2, an upper slide rail 17 is provided on the upper side of the rear door opening 12. A center slide rail 18 is provided at the center of the height direction on the rear side of the rear door opening 12. A lower slide rail 19 is provided on the lower side of the rear door opening 12, i.e., on the lower side of the rocker 30.

Referring to Figures 1 and 2, the sliding door 20 is provided with guide roller units 25 and the like at its upper, lower, and intermediate positions (for convenience, in Figure 1, only the lowest guide roller unit is designated by the corresponding reference numeral 25). The sliding door 20 is configured so that the corresponding guide roller units 25 and the like move (slide, etc.) along the slide rails 17-19, allowing it to slide along these slide rails 17-19. The sliding door 20 moves linearly in the fore-and-aft direction of the vehicle near the fully open position, and then gradually moves diagonally inward (to the right) in the vehicle width direction as it approaches the fully closed position (see the sliding door movement trajectory Do in Figure 4).

[Vehicle undercarriage]
In the vehicle undercarriage structure of this embodiment, as shown in FIG. 2 , the lower slide rail 19 is disposed on the vehicle underside (below the rocker) of the rocker 30. This increases the degree of freedom in selecting the shape of the rocker 30, making it easier to ensure rigidity. Furthermore, an internal member 3, such as a battery installed under the floor of the vehicle 2, is disposed on the inner side (right side) of the rocker 30 in the vehicle width direction. The rocker 30 is disposed at a height position higher than the height position H of the internal member 3, which facilitates securing a sufficient height distance from the ground (ground clearance). The internal member 3 is formed in a rectangular shape that is elongated in the fore-and-aft direction of the vehicle when viewed from above as shown in FIG. 3 , and is disposed in the area from the front door opening 11 to the rear door opening 12.

In the above-described configuration, as shown in FIG. 2, the arm portion 23 of the sliding door 20 is connected to the lower slide rail 19 located under the rocker. The arm portion 23 is located under the rocker so as to face the inside (right side) in the vehicle width direction, i.e., the internal member 3. With this type of configuration, care must be taken to ensure that when an impact load is applied from the outside (left side) in the vehicle width direction, the arm portion 23 does not move inward in the vehicle width direction and hit the internal member 3 hard. Therefore, in this embodiment, the moving structure 60 described below prevents the arm portion 23 under the rocker from hitting the internal member 3 under the floor hard. The vehicle's undercarriage structure will be described in detail below, in the order of rocker 30, lower slide rail 19, sliding door 20, internal member 3, and moving structure 60.

[locker]
First, the rocker 30 shown in FIG. 2 is cylindrically formed from an outer rocker 31 and an inner rocker 32 and is provided along the lower edge of the rear door opening 12. The outer rocker 31 has an upper plate surface 311, a lower plate surface 312, and a left plate surface 313, forming a substantially horizontally U-shaped cross section, with the inner side (right side) in the vehicle width direction open. The upper plate surface 311 of the outer rocker 31 is bent inward and upward in the vehicle width direction. The lower plate surface 312 of the outer rocker 31 extends linearly inward in the vehicle width direction and protrudes more inward in the vehicle width direction than the upper plate surface 311. An upper flange portion 31a bent toward the upper side of the vehicle is formed at the upper end of the upper plate surface 311, and a lower flange portion 31b bent toward the lower side of the vehicle is formed at the lower end of the lower plate surface 312. The upper plate surface 311 and the lower plate surface 312 are continuous with a left plate surface 313 that extends in the vertical direction of the vehicle on the outer side (left side) of the outer rocker 31 in the vehicle width direction.

The inner rocker 32 shown in Figure 2 has an approximately horizontal U-shaped cross section formed by its upper plate surface 321, lower plate surface 322, and right side plate surface 323, with the outer side (left side) in the vehicle width direction open. The upper plate surface 321 of the inner rocker 32 juts outward relatively significantly, extending outward in the vehicle width direction before sloping downward. Upper and lower flange portions 32a, 32b bent in the vertical direction of the vehicle are also formed at the upper and lower end positions of the inner rocker 32.

The rocker 30 shown in FIG. 2 is formed with a generally rectangular cylindrical cross section by joining the outer rocker 31 and inner rocker 32 together in the vehicle width direction. Specifically, the upper flanges 31a, 32a and the lower flanges 31b, 32b of the rocker 30 are joined together by welding or other means. Because the rocker 30 is formed with a generally rectangular cylindrical cross section that omits recesses for slide rails, it has a cross-sectional shape that contributes to ensuring rigidity. Furthermore, the rocker 30's highly rigid cross-sectional shape allows for a more compact design, such as by reducing its vertical dimensions. This allows the rocker 30 to be installed at a height higher than the height position H of the internal member 3, thereby contributing to ensuring sufficient ground clearance. Furthermore, by installing the rocker 30 at a relatively high height, the center pillar 13 shown in FIG. 1 can be shortened, thereby minimizing the weight of the vehicle 2. Furthermore, because the rocker 30 does not need to be made any taller than necessary, it also facilitates ease of ingress and egress.

In the rocker 30 shown in Figure 2, the upper flanges 31a, 32a are located near the outer (left) end in the vehicle width direction. A scuff 40, which serves as a tread, is provided on the upper side of the rocker 30, extending in the vehicle width direction. A weather strip WS is fitted in the gap between the front end of the scuff 40 and the rocker 30 (the upper flanges 31a, 32a). A sheet-like carpet 41 is laid on the inner (right) side of the scuff 40 in the vehicle width direction, covering the floor side of the vehicle 2. The lower plate surface 312 of the outer rocker 31 forms the lower surface of the rocker 30, and the lower flanges 31b, 32b are located near the inner end of the lower plate surface 312 in the vehicle width direction.

[Lower slide rail (slide rail)]
Next, the lower slide rail 19 is disposed below the rocker (below the vehicle of the lower plate surface 312) as shown in FIG. 2. The lower slide rail 19 is formed so as to follow the movement locus Do of the sliding door 20 shown in FIG. 4, and has a bent portion 190 and a straight portion 191. The bent portion 190 is formed on the front side of the lower slide rail 19, and is gradually bent inward in the vehicle width direction (to the right) as it approaches the front of the vehicle. The lower slide rail 19 is formed with a proximity region 19A that is relatively close to the internal member 3 in a region from the front end of the bent portion 190 to the rear end. The straight portion 191 is continuous with the rear end of the bent portion 190, and extends linearly so as to follow the opening and closing direction of the sliding door 20 (the vehicle front-rear direction).

In the cross-sectional view shown in FIG. 2 , the lower slide rail 19 is formed from an upper wall portion 192, a lower wall portion 193, and a vertical wall portion 194 connecting the upper and lower wall portions. The upper wall portion 192 is formed with an inverted U-shaped cross section with an open underside, allowing the guide rollers 26 of the guide roller unit 25 (described later) to be slidably fitted therein. The lower wall portion 193 is a flat plate-shaped portion located on the underside of the upper wall portion 192, and is capable of slidably supporting the load rollers 27 of the guide roller unit 25 (described later). The upper wall portion 192 and the lower wall portion 193 are continuous with a vertical wall portion 194 extending in the vertical direction of the vehicle on the inner side (right side) of the upper wall portion 192 in the vehicle width direction. As a result, the lower slide rail 19 is formed in the shape of a hollow column with an open outer side (left side) of the lower slide rail 19, and is configured to allow the guide roller unit 25 of the sliding door 20 (described later) to be inserted from the outer side of the vehicle width direction. Furthermore, the vertical wall portion 194 of the lower slide rail 19 forms the end portion 19E on the inner side in the vehicle width direction.

As shown in FIG. 2 , the lower slide rail 19 is fixed to the rocker 30 via connecting members 35, 36, etc., extending in the vehicle width direction. For example, a front connecting member 35 is disposed at the front end of the bent portion 190 of the lower slide rail 19. This front connecting member 35 is bent in a crank shape in cross section, and its left end portion 350 on the outer (left) side in the vehicle width direction is one step higher. The left end portion 350 of the front connecting member 35, which is one step higher, is fixed to the lower plate surface 312 of the rocker 30. The lower slide rail 19 is fixed to the right end portion 351 of the front connecting member 35, which is one step lower, so that it protrudes below the vehicle. The front end of the bent portion 190 of the lower slide rail is disposed directly below the flange portions 31b, 32b on the lower side of the rocker 30.

A rear connecting member 36 is also disposed behind the bent portion 190 shown in Figure 2. Contrary to the front connecting member 35, this rear connecting member 36 has its left end (reference number omitted) fixed to the underside of the rocker 30, which is one step higher on the inner side (right side) in the vehicle width direction. The rear connecting member 36 is formed to extend outward (left side) in the vehicle width direction than the rocker 30, and the lower right end (reference number omitted) is fixed to the lower slide rail 19 so that it protrudes below the vehicle. Referring to Figure 5, the straight portion 191 of the lower slide rail 19 is also fixed to the rocker 30 via another connecting member 37.

As shown in Figures 2 and 5, the lower slide rail 19 is thus disposed below the rocker 30 via connecting members 35-37 fixed to the rocker 30. In the vehicle's undercarriage, the lower slide rail 19 is positioned on the outer side (left side) of the vehicle width, utilizing the space below the sliding door 20, thereby avoiding interference with the internal member 3. Specifically, to avoid interference with the internal member 3, the front end of the bent portion 190 of the lower slide rail 19 is disposed directly below the flange portions 31b, 32b on the underside of the rocker 30. Furthermore, by locating the portion from the rear of the bent portion 190 to the straight portion 191 on the outer side of the rocker 30 in the vehicle width direction, the vehicle width dimension of the lower slide rail 19 is ensured.

[Sliding door]
The sliding door 20 shown in FIG. 2 is formed by joining a door outer panel 20a and a door inner panel 20b at their peripheral edges. A slide rail connecting arm 23 is fixed to the lower end of the door inner panel 20b of the sliding door 20. The arm 23 has a generally L-shaped cross section and is fixed to the lower end of the sliding door 20 by a vertical wall-like fixing portion 23a extending in the vehicle vertical direction. The arm 23 extends substantially horizontally from the lower end of the fixing portion 23a toward the inside of the vehicle (the protruding portion 62, which is a part of the moving member, will be described later in detail). With a guide roller unit 25 (described later) disposed thereon, the arm 23 extends toward the front and inside (right side) of the vehicle width direction as shown in FIG. 4.

[Guide roller unit (end of arm part on inside of vehicle)]
2 and 4, the guide roller unit 25 includes front and rear guide rollers 26 and a load roller 27 (for convenience, the front and rear guide rollers are denoted by the common reference numeral 26 in FIG. 4). The arm portion 23 has an upper support portion 261 for the guide rollers and a lower support portion 271 for the load roller at an end portion 23E on the inner side (right side) in the vehicle width direction shown in FIG. 4. The upper support portion 261 is formed in a substantially U-shape in plan view, and a vertically oriented first shaft member 260 is provided at its bifurcated free end. A horizontally oriented guide roller 26 is rotatably supported by each first shaft member 260, and each guide roller 26 is slidably fitted in the upper wall portion 192 of the lower slide rail 19 shown in FIG. 2.

The arm portion 23 shown in FIG. 4 is provided with a vertically oriented second shaft 270 at its end 23E on the inner side (right side) in the vehicle width direction, and a lower support portion 271 is rotatably supported on this vertically oriented second shaft 270. The lower support portion 271 also supports a horizontally oriented third shaft 272 that protrudes inward in the vehicle width direction, and a vertically oriented load roller 27 is rotatably supported on this third shaft 272. The load roller 27 can be turned to align with the lower slide rail 19 by the lower support portion 271 that supports it rotating around the second shaft 270. The load roller 27 is slidably supported on the lower wall portion 193 of the lower slide rail 19 shown in FIG. 2.

[Internal parts]
Next, the inner member 3 shown in FIGS. 2 and 3 is a member disposed under the floor, i.e., on the vehicle widthwise inner side of the rocker 30 (to the right in FIG. 2 ), as described above. Examples of this type of inner member 3 include an on-board battery and a fuel storage member for storing liquid or gaseous fuel. The inner member 3 is disposed at a height lower than the rocker 30, as shown in FIG. 2 , so that a side surface portion 300 of the inner member 3 in the vehicle width direction faces the lower slide rail 19 and the arm portion 23. The side surface portion 300 of the inner member 3 has a flange portion 301 at its central position in the vehicle up-down direction, which protrudes outward in the vehicle width direction (to the left). An upper portion 302 of the side surface portion 300, which is above the flange portion 301, is disposed at approximately the same height as the lower slide rail 19 and the arm portion 23. Furthermore, a lower portion 303 of the side surface portion 300, which is below the flange portion 301, has a stepped shape that is recessed relatively inward in the vehicle width direction. The recessed lower portion 303 of the side surface portion 300 is disposed at a height lower than the lower slide rail 19 and the arm portion 23 so that an impact absorbing member 50 (described later) can be connected thereto.

[Impact absorbing member]
In the vehicle undercarriage, an impact absorbing member 50 can be provided on the outer side (left side) of the inner member 3 in the vehicle width direction. For example, the impact absorbing member 50 shown in Figures 2 and 3 is a member that can absorb impact loads applied from the outer side in the vehicle width direction, and is connected to the side portion 300 of the inner member 3. This impact absorbing member 50 is provided with a connecting portion 51 that connects to the side portion 300 in a region on the inner side (right side) in the vehicle width direction as shown in Figure 2. This connecting portion 51 is formed so as to protrude inward in the vehicle width direction from a lower portion of the impact absorbing member 50, and is fitted into a lower portion 303 of the side portion 300 of the inner member 3. In addition, a connecting plate portion 52 is fixed to the underside of the connecting portion 51 by fastening or the like (see first fastening point FX1 in Figure 2). This connecting plate 52 is formed to extend inward in the vehicle width direction from the connecting portion 51, and the inner portion of the connecting plate 52 in the vehicle width direction is fixed to the inner member 3 by fastening or the like (see second fastening point FX2 in Figure 2). As a result, the connecting portion 51 of the impact absorbing member 50 is sandwiched between the flange portion 301 of the inner member 3 and the connecting plate 52, and is connected to the lower portion 303 of the side surface portion 300 by recessed and projecting engagement.

2 and 4, the impact absorbing member 50 is formed to extend outward (to the left) from the inner member 3 in the vehicle width direction, protruding outward in the vehicle width direction beyond the rocker 30. In the vicinity region 19A of the lower slide rail 19 shown in FIG. 4, the impact absorbing member 50 protrudes outward in the vehicle width direction further than the lower slide rail 19. More specifically, referring to FIG. 2, if the position of the vehicle width outer end of the bent portion 190 in the vicinity region 19A is defined as a reference position 19X, the vehicle width outer end 50X of the impact absorbing member 50 is located at the same position as or further outward in the vehicle width direction than the reference position 19X. The impact absorbing member 50 gradually protrudes outward in the vehicle width direction more than the lower slide rail 19 as it moves toward the front of the vehicle in the vicinity region 19A. This enables the impact absorbing member 50 to be the first to receive an impact load applied to the vicinity region 19A from the vehicle width outer side.

As shown in Figures 3 and 4, the impact absorbing member 50 is formed to extend in the fore-and-aft direction of the vehicle, and has a length that covers approximately the entire length of the inner member 3. This allows the impact absorbing member 50 to receive an impact load applied from the outside (left side) in the vehicle width direction before the inner member 3. Furthermore, by being provided over approximately the entire length of the inner member 3, the impact absorbing member 50 is able to press against the center of gravity 3C of the inner member 3. In other words, the center position of the inner member 3 in the vehicle width direction and the fore-and-aft direction is the center of gravity 3C. If an imaginary line VL is set that extends in the vehicle width direction through the center of gravity 3C of the inner member 3, the impact absorbing member 50 is arranged so that a portion of it overlaps the imaginary line VL.

[Moving structure]
2 and 4, the vehicle undercarriage is further provided with a moving structure 60 that moves the vehicle-inner (right) end 23E of the arm portion 23 toward the vehicle upper side when an impact load is applied. This moving structure 60 can be composed of a receiving portion 61 of the impact absorbing member 50 and a protruding portion 62 and a weakened portion 63 of the arm portion 23. That is, as shown in FIG. 2, the impact absorbing member 50 is provided with a vertical wall-shaped receiving portion 61 that protrudes toward the vehicle upper side, thereby forming a receiving member that can receive the vehicle-width-direction-inner (right) end 23E of the arm portion 23. The vertical wall-shaped receiving portion 61 is provided so as to protrude toward the vehicle upper side on the vehicle-width-direction outer side (left side) of the connecting portion 51, and is therefore positioned between the arm portion 23 and the upper portion 302 of the internal member 3 in the vehicle width direction. Furthermore, the receiving portion 61 is positioned so as to receive the vehicle-width-direction-inner end 23E of the arm portion 23, thereby also receiving the vehicle-width-direction-inner end 19E of the lower slide rail 19.

The arm portion 23 shown in Figure 2 is provided with a protruding portion 62 that protrudes outward in the vehicle width direction (left side) as a moving structure 60. This protruding portion 62 of the arm portion 23 is formed by bending the lower end of the fixed portion 23a outward in the vehicle width direction, and protrudes further outward in the vehicle width direction than the fixed portion 23a (the point where it is fixed to the sliding door 20). This allows the arm portion 23 to withstand impact loads applied from the outside in the vehicle width direction at the protruding portion 62. Furthermore, by bending the lower end of the fixed portion 23a to form the protruding portion 62, the length of the bent portion that forms the protruding portion 62 is increased.

The upper surface of the arm portion 23 shown in Figure 2 is provided with a weak portion 63 that constitutes the moving structure 60, approximately at the middle in the vehicle width direction. This weak portion 63 is a groove-shaped, thin-walled portion provided on the upper surface of the arm portion 23, and is weaker and more easily bent than the rest of the arm portion 23. The weak portion 63 extends linearly in the fore-and-aft direction of the vehicle on the upper surface of the arm portion 23, following the side portion 300 of the internal member 3 shown in Figure 4. With the weak portion 63 provided in the middle in the vehicle width direction, the arm portion 23 is thus more likely to bend and deform downward toward the vehicle, starting from the weak portion 63 (see Figure 7).

[Opening and closing operation of the sliding door (function of the lower slide rail)]
Here, the opening and closing operation of the sliding door 20 by the lower slide rail 19 will be described. First, when the sliding door 20 is in the fully open position as shown in FIG. 5 , the sliding door 20 is positioned on the vehicle rear side of the rear door opening 12, as indicated by the dashed lines in FIGS. 3 and 4 . At this time, the guide roller unit 25 provided on the arm portion 23 is positioned at the rear end position of the straight portion 191 of the lower slide rail 19, as indicated by the dashed line in FIG. 4 . Next, the sliding door 20 is slid toward the front of the vehicle (in the closing direction) to fully close the rear door opening 12. At this time, referring to FIG. 4 , the guide roller unit 25 moves toward the front of the vehicle along the straight portion 191 of the lower slide rail 19, causing the sliding door 20 to move linearly toward the front of the vehicle (see the movement locus Do of the sliding door 20 shown in FIG. 4 ). Next, the guide roller unit 25 moves along the bent portion 190, causing the sliding door 20 to gradually move inward (to the right) in the vehicle width direction as it approaches the fully closed position. When the sliding door 20 is fully closed, the guide roller unit 25 of the arm portion 23 is positioned at the front end of the bent portion 190 (see the state indicated by the solid line in FIG. 4).

[Sliding door in fully closed state]
As shown in FIG. 2 , when the sliding door 20 is in the fully closed position, an exterior portion (garnish) at the lower end of the sliding door 20 covers the outer side (left side) of the lower slide rail 19 in the vehicle width direction. The arm portion 23 of the sliding door 20 is connected to the lower slide rail 19 below the rocker, and the underfloor internal member 3 is disposed on the inner side (right side) of the arm portion 23 in the vehicle width direction. In this type of configuration, as described above, care must be taken to prevent the arm portion 23, which receives an impact load from the outer side of the vehicle width direction, from moving inward in the vehicle width direction and strongly hitting the internal member 3. Therefore, the vehicle undercarriage is provided with a moving structure 60 that moves the inner end 23E of the arm portion 23, to which an impact load is applied, toward the upper side of the vehicle. In the above configuration, when an impact load is applied to the arm portion 23 from the outer side of the vehicle width direction, the inner end 23E of the arm portion 23 in the vehicle width direction is moved in a direction away from the internal member 3. Therefore, the function of the moving structure 60 (receiving portion 61, protruding portion 62, and fragile portion 63) will be described in more detail below.

[Function of the moving structure]
4 and 6 , let us consider a case in which an impact load F1 during a vehicle side collision is applied to the front end position of the lower slide rail 19, i.e., the position where the arm portion 23 is disposed in the fully closed state. In the above-described configuration, the impact load F1 during a vehicle side collision is applied to the arm portion 23, causing the arm portion 23 to move inward (to the right) in the vehicle width direction (see the direction indicated by reference symbol A2 in FIG. 6 ). Furthermore, the arm portion 23 has a protruding portion 62 that protrudes outward (to the left) in the vehicle width direction, so that the protruding portion 62 can more reliably bear the impact load F1. Furthermore, as described above, the receiving portion 61 of the impact absorbing member 50 is disposed at the end of the arm portion 23's movement. Therefore, the end 23E of the arm portion 23 on the inner side in the vehicle width direction is received by the receiving portion 61 of the impact absorbing member 50 (receiving member) before reaching the inner member 3.

As shown in Figure 6, an impact load F1 is applied to the arm portion 23 from the outside (left side) in the vehicle width direction, with the end 23E on the inside (right side) side of the arm portion 23 supported by the support portion 61. The arm portion 23 has a groove-shaped weakened portion 63 extending in the fore-and-aft direction of the vehicle to facilitate bending deformation. Therefore, when the impact load F1 is applied to the arm portion 23, it bends smoothly from the weakened portion 63 toward the bottom of the vehicle, forming an inverted V-shape, as shown in Figure 7. At this time, the length of the arm portion 23 is increased by the protruding portion 62, ensuring sufficient length to allow bending deformation toward the bottom of the vehicle. This excess length allows the arm portion 23 to bend more reliably toward the bottom of the vehicle. As the arm portion 23 bends and deforms into an inverted V shape, the end portion 23E on the inner side in the vehicle width direction of the arm portion 23 moves toward the upper side of the vehicle relative to the internal member 3, i.e., in a direction away from the internal member 3 (see the arrow indicated by the symbol A3 in Figure 7). In this way, by using the movement structure 60 to move the end portion 23E on the inner side in the vehicle width direction of the arm portion 23 in a direction away from the internal member 3, the arm portion 23 is less likely to come into strong contact with the internal member 3.

[Vehicle undercarriage advantages]
In the above-described configuration, when an impact load is applied to the arm portion 23 from the outside in the vehicle width direction (left side), the end portion 23E on the inside in the vehicle width direction (right side) of the arm portion 23 is moved by the movement structure 60 in a direction intersecting the vehicle width direction, i.e., in a direction away from the internal member 3. This makes it less likely that the arm portion 23 to which the impact load is applied will strongly hit the internal member 3. Therefore, according to this embodiment, it is possible to prevent the arm portion 23 below the rocker from strongly hitting the internal member 3 on the underfloor side in the event of a vehicle collision, etc.

Furthermore, in this embodiment, the movement structure 60 allows the inner (right) end 23E of the arm portion 23 in the vehicle width direction to move toward the upper side of the internal member 3. In this embodiment, when an impact load is applied to the arm portion 23, it is received by the impact absorbing member 50 (receiving member), making it difficult for the arm portion 23 to move inward in the vehicle width direction, resulting in bending deformation in a direction other than the vehicle width direction. The bending deformation of the arm portion 23 in response to the impact load causes the inner end 23E of the arm portion 23 in the vehicle width direction to move in a direction intersecting the vehicle width direction. In this embodiment, when an impact load is applied to the arm portion 23, the inner end 23E of the arm portion 23 in the vehicle width direction is received by the receiving portion 61 of the impact absorbing member 50 (receiving member) before it reaches the internal member 3. In this embodiment, the impact load is received by the protruding portion 62, thereby more reliably bending and deforming the arm portion 23 provided on this protruding portion 62. Additionally, by increasing the length of the arm portion 23 at the protruding portion 62 and ensuring excess length, the arm portion 23 can bend and deform more reliably. In this embodiment, the weakened portion 63 allows the arm portion 23 to bend and deform smoothly when an impact load is applied.

[Another benefit of the vehicle's undercarriage (impact absorbing member function)]
Furthermore, in the above-described configuration, the impact absorbing member 50 serves to prevent the lower slide rail 19 from strongly hitting the inner member 3. Now, with reference to FIGS. 4 and 6 , let us consider a case in which an impact load F1 during a vehicle side collision is applied to the proximity region 19A of the lower slide rail 19. In this case, in the above-described configuration, the outer (left) end 50X of the impact absorbing member 50 in the vehicle width direction is positioned at the same position as the reference position 19X (the position of the outer end of the lower slide rail 19 in the vehicle width direction) or protrudes outward in the vehicle width direction from there, as described above. Therefore, the outer end 50X of the impact absorbing member 50 in the vehicle width direction is the first to bear the impact load F1 during a vehicle side collision. Then, as shown in FIG. 6 , the impact absorbing member 50 is crushed and deformed to absorb the impact load F1, thereby reducing the impact load F1 applied to the lower slide rail 19. As a result, the lower slide rail 19 is prevented from moving inward (to the right) in the vehicle width direction due to the reduction in the impact load F1, and is therefore less likely to come into strong contact with the internal member 3.

Referring also to FIG. 6 , the impact absorbing member 50 is connected to the side surface 300 of the inner member 3 at a connection point 51 on the vehicle's inner (right) side in the vehicle width direction. As a result, when an impact load F1 is applied to the impact absorbing member 50, the impact absorbing member 50 presses the inner member 3, which is in contact with the connection point 51, inward in the vehicle width direction, i.e., in the direction away from the lower slide rail 19 (see the arrow indicated by symbol A1 in FIG. 6 ). At this time, a portion of the impact absorbing member 50 can press against the center of gravity 3C of the inner member 3, allowing the inner member 3 to move inward in the vehicle width direction more stably. Furthermore, the impact absorbing member 50 is provided with a receiving portion 61 positioned to receive the inner end 19E of the slide rail 19 in the vehicle width direction. Therefore, when an impact load F1 is applied to the lower slide rail 19, the receiving portion 61 of the impact absorbing member 50 receives the lower slide rail 19 just before the inner member 3. The lower slide rail 19, to which the impact load F1 is applied, presses the impact absorbing member 50, which is provided with the receiving portion 61, inward in the vehicle width direction. This causes the impact absorbing member 50 to move the inner member 3 further inward in the vehicle width direction, maintaining the distance between this inner member 3 and the slide rail 19 and making it possible to avoid contact between them as much as possible.

The vehicle undercarriage of this embodiment is not limited to the above-described embodiment and may take various other forms. While the configuration of the moving structure is illustrated in this embodiment, this is not intended to limit the configuration of the moving structure. For example, the moving structure may be configured to move the outer end of the arm portion in a direction intersecting the vehicle's interior/exterior direction. In the case of Figure 4, the intersecting direction can be at least one of the vehicle's upper, lower, front, and rear directions. Furthermore, when the outer end of the arm portion is bent using the moving structure, the direction of movement (bending direction) can be determined taking into account the relative positions of the arm portion, the impact absorbing member, and the rocker. That is, when the vertical gap between the arm portion and the impact absorbing member is relatively large, it is desirable to bend the arm portion toward the bottom of the vehicle. In this case, it is desirable to provide a weak portion on the upper surface of the arm portion. Furthermore, when the vertical gap between the arm portion and the rocker is relatively large, it is desirable to bend the arm portion toward the top of the vehicle. In this case, it is desirable to provide a weak portion on the lower surface of the arm portion. The weak portions may be groove- or hole-shaped thin portions or through-holes (including elongated holes) intermittently provided on the arm portion. Furthermore, when the arm portion is bent in the vehicle longitudinal direction, a notched weak portion extending in the vehicle longitudinal direction may be provided on either the front or rear periphery of the arm portion. Furthermore, it is desirable to provide at least one of the above-described configurations, particularly a receiving member, as the moving structure. Examples of such receiving members include an impact absorbing member, as well as a member disposed on the vehicle exterior of the internal member (such as a locker, an underfloor framework member, or a receiving member separate from these). Furthermore, the receiving member (receiving portion) may be in contact with the arm portion before the impact load is applied. Furthermore, when a protruding portion is provided, examples of such a protruding portion include a side wall-shaped portion or a thick portion protruding from the arm portion toward the vehicle exterior. The opening and closing direction of the slide rail is not necessarily limited to the vehicle longitudinal direction. Furthermore, a vehicle may be equipped with multiple internal members of the same or different types, and the configuration of this embodiment may be applied to at least one of the multiple internal members. The rocker only needs to be tubular and omit the recess for the slide rail, and various shapes such as a rectangular or cylindrical shape can be used.

While this embodiment exemplifies the configuration of a slide rail and an impact absorbing member as a structure related to the aforementioned other advantages, the configuration of these members is not intended to be limiting. In a vehicle undercarriage, the vehicle-outside end of the impact absorbing member can be positioned at an appropriate position on the slide rail or along substantially the entire length of the slide rail, at the same position as the reference position (the position where the vehicle-outside end of the slide rail is located) or further outward from the reference position. For example, referring to FIG. 4, the vehicle-outside end of the impact absorbing member can be positioned along substantially the entire length of the bent portion, or along part or substantially the entire length of the straight portion, at the same position as the reference position or further outward from the reference position. Furthermore, the impact absorbing member may simply be adjacent to the internal member and does not necessarily need to be connected. As long as the impact absorbing member can contact the internal member when an impact load is applied, a gap may be provided between the two members (they may be close to each other). The impact absorbing member may also be provided on at least a portion of the internal member (side portion) in the fore-and-aft direction of the vehicle. In this case, it is desirable, but not limited to, that a portion of the impact absorbing member be positioned on an imaginary line passing through the center of gravity of the internal member. In this embodiment, an example in which a receiving portion is provided on an impact absorbing member has been described. However, the receiving portion can also be provided on various members (such as the above-mentioned receiving member) arranged on the vehicle widthwise outer side of the internal member. The receiving portion can also have various shapes in addition to a vertical wall shape, and the surface on the outer side of the vehicle can be tapered (for example, a tapered shape sloping toward the upper right in Figure 4). At least part of the structure related to other advantages can be omitted as needed.

2 Vehicle 3 Internal member 3C (of internal member) Center of gravity 300 Side portion 301 (of internal member) Flange portion 302 Upper portion 303 (of internal member) Lower portion 10 Vehicle body 11 Front door opening 12 Rear door opening 13 Center pillar 15 Front door 17 Upper slide rail 18 Center slide rail 19 Lower slide rail (slide rail of the present invention)
190 Bent portion 191 Straight portion 192 Upper wall portion 193 Lower wall portion 194 Vertical wall portion 19X Reference position (position of the end of the slide rail on the vehicle outer side)
19A Proximal region 19E Vehicle width direction inner end of lower slide rail (vehicle inner end of slide rail)
20 Sliding door 20a Door outer panel 20b Door inner panel 23 Arm portion 23a Fixing portion 23E Vehicle width direction inner end of arm portion (vehicle inner end of arm portion)
25 Guide roller unit 26 Guide roller 27 Load roller 30 Rocker 31 Rocker outer 311 (of rocker outer) upper plate surface 312 (of rocker outer) lower plate surface 313 (of rocker outer) left plate surface 32 Rocker inner 321 (of rocker inner) upper plate surface 322 (of rocker inner) lower plate surface 323 (of rocker inner) right plate surface 31a, 32a Upper flange portions 31b, 32b Lower flange portions 35 Front connecting member 350 (of front connecting member) left end portion 351 (of front connecting member) right end portion 36 Rear connecting member 37 Another connecting member 40 Scuff 41 Carpet 50 Impact absorbing member (receiving member)
50X: Outer end of the impact absorbing member in the vehicle width direction (outer end of the impact absorbing member on the vehicle side)
51 Connection portion 52 Connection plate portion 60 Moving structure 61 Receiving portion 62 Protruding portion 63 Weak portion 260 First shaft member 261 Upper support portion 270 Second shaft member 271 Lower support portion 272 Third shaft member FX1, FX2 Fastening point WS Weather strip VL Virtual line

Claims (5)

A vehicle undercarriage having a sliding door that opens and closes a door opening in a vehicle body, and a cylindrical locker that forms a lower edge of the door opening,
A slide rail that supports the sliding door so that the sliding door can slide in an opening and closing direction is provided on the vehicle underside of the locker so as to be connected to an arm portion of the sliding door, and when a direction perpendicular to the opening and closing direction is defined as an inside-outside direction of the vehicle based on a plan view in the vehicle up-down direction, the arm portion extends toward the inside of the vehicle so as to face an internal member arranged on the underside of the floor of the vehicle,
a moving structure is provided that moves the end portion of the arm portion on the inside of the vehicle to which the impact load is applied in a direction intersecting with the vehicle inward/outward direction,
The moving structure is a vehicle undercarriage in which a receiving member is provided at a position capable of receiving the end of the arm portion on the inside of the vehicle when an impact load is applied . 2. The vehicle undercarriage structure according to claim 1, further comprising a moving structure that moves the end of the arm portion on the vehicle inner side to which an impact load is applied to the vehicle upper side or lower side of the internal member. 2. The vehicle undercarriage structure according to claim 1, wherein the receiving member has a receiving portion for receiving an end portion of the arm portion on an inner side of the vehicle, the receiving portion being provided between the arm portion and the internal member in the vehicle inside-outside direction . 4. The vehicle undercarriage structure according to claim 1, wherein the moving structure includes a protruding portion that protrudes a part of the arm portion toward the outside of the vehicle beyond a fixed portion of the arm portion relative to the sliding door . 4. The vehicle undercarriage structure according to claim 1, wherein the moving structure is provided with a weakened portion that promotes deformation of the arm portion in a direction intersecting with the vehicle interior-exterior direction .