JP2012091536A - Vehicle chassis frame - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a truck chassis frame which makes the improvement of durability compatible with the weight reduction of cross members by preventing the generation of a stress concentration so as to enable the deformation of the chassis frame to be absorbed by the whole of cross members by smoothly changing connection portions of end edges of an upper side or a lower side of a vertical wall with end edges of a reinforcing flange in the vehicle width direction, in the cross member which is disposed at the rear end of the truck chassis frame and has the vertical wall and the reinforcing flange bent in the vehicle longitudinal direction at the intermediate portion of either of the upper side or the lower side of the vertical wall.SOLUTION: The cross member has the vertical wall 51 which is extended in the vehicle width direction between read ends of right and left pair of side rails 2, 3 extended in the vehicle longitudinal direction, and the reinforcing flange 54 bent in the vehicle longitudinal direction at the intermediate portion of either of the upper side or the lower side of the vertical wall 51. The connection portions E of the end edges of the vertical wall 51 with those of the reinforcing flange 54 are changed smoothly.

Description

  The present invention relates to weight reduction of a chassis frame for trucks.

  In general, as shown in FIG. 7A, a part of the truck chassis frame is a pair of left and right right side rails 01 extending in the vehicle front-rear direction with an interval in the vehicle width direction of the vehicle. And the left side rail 02 is arrange | positioned. A cross member 03 extending in the vehicle width direction between the pair of right and left right side rails 01 and left side rail 02 and having both ends fixed to the pair of right and left right side rails 01 and left side rail 02 is provided in the vehicle front and rear direction. A plurality are arranged at intervals, and are formed in a ladder shape.

JP-A-2007-99228 (Patent Document 1) is disclosed as a prior art.
In the case of the prior art disclosed in Patent Document 1, as shown in FIGS. 7A and 7B, the cross member 03 includes a cross beam 04 in which a pair of left and right right side rails 01 and left side rails 02 are bridged (of the present application). Equivalent to a cross member), a cross member 06 disposed outside the left and right side rails 01 and 02, and a plate member 05 connecting the upper surfaces of the left and right cross members 06.

  As shown in FIG. 7 (B), the cross beam 04 is located at both ends of the main beam 041 in the vehicle width direction and the main beam 041 that bridges between the left and right side rails 01 and 02, and the left and right side rails 01 and 02. The connecting flange 042 is fastened to the web surfaces 011 and 012 via a fastening member. The main beam 041 has a U-shaped cross-section in which a flange 043 extending from the upper side and the lower side in the vehicle front-rear direction is disposed at the middle in the vehicle width direction.

Therefore, when the left and right side rails 01 and 02 are twisted, the connection portion (Z portion) between the portion of the main beam 041 that is only the vertical wall and the portion where the flange 043 is formed is not smoothly connected. A change in the cross-sectional rigidity at the portion (Z portion) is large, and when the chassis frame is twisted, there is a problem that high stress is easily generated in the portion and cracks are easily generated.
Further, since it has a U-shaped cross section in which a flange 043 extending in the vehicle front-rear direction from the upper side and the lower side of the main beam 041 in the vehicle width direction is provided, the weight increases, The material cost is also increased, and there is a problem that the weight and cost increase.

Further, in Japanese Patent Laid-Open No. 7-290920 (Patent Document 2), as shown in FIG. 8, a pulling hook 08 is attached to the web surface of the rear end portion of the side rail 07. The tow hook 08 engages with the engagement protrusion 081 of the tow hook 08 in the engagement hole 071 at the rear end portion of the side rail 07, and the tow hook 08 is pulled to the mounting hole 072 drilled forward in the vehicle front-rear direction from the engagement hole 071. It is fastened by a spring washer 091 and a nut 092 via a bolt 09 that has passed through the mounting hole 082 of the hook 08.
In this case, the phase of the traction force acting on the traction hook 08 (the engagement position of the traction rope) and the web surface of the side rail 07 to which the traction hook 08 is attached are out of phase in the vehicle width direction. A moment in a direction perpendicular to the web surface acts around the mounting hole 072 on the web surface, and high stress is likely to be generated on the outer peripheral portion of the mounting hole 072 on the web surface, causing deformation and further cracking. There is a problem that is likely to be.

JP 2007-99228 A JP 7-290920 A

  Accordingly, the present invention has been made in view of the above-described problems, and is an intermediate between the vertical wall of the cross member disposed at the rear end portion of the truck chassis frame and either the upper side or the lower side of the vertical wall. The cross-sectional rigidity of the vertical wall and the reinforcing flange is formed by connecting the edge of the reinforcing flange bent in the vehicle longitudinal direction to the edge of the upper or lower side of the vertical wall. By changing the width of the cross member so that it can be deformed by the torsion of the chassis frame over a wide range of the cross member, stress concentration is prevented and both the durability of the cross member is improved and the weight is reduced. An object of the present invention is to provide a chassis frame for a truck.

  The present invention achieves such an object, and is arranged in the vehicle width direction between a pair of left and right side rails arranged in the vehicle width direction and extending in the vehicle front-rear direction, and the pair of left and right side rails. A vehicle chassis frame structure having a plurality of cross members having both ends coupled to the side rails, and a vertical wall extending in the vehicle width direction between the rear ends of the pair of side rails, A reinforcing flange bent in the vehicle front-rear direction at an intermediate portion on either one of the upper side or the lower side of the wall, and the edge of the upper side or the lower side of the vertical wall and the edge of the reinforcing flange in the vehicle width direction The bent connection portion is smoothly changed.

In this invention, since the reinforcing flange bent in the vehicle longitudinal direction is arranged on either the upper side or the lower side with respect to the conventional cross member having a U-shaped cross section, the weight and material cost can be reduced. .
In addition, since the bent connection portion between the edge of the vertical wall and the edge of the reinforcing flange in the vehicle width direction is smoothly changed, the cross-sectional rigidity change of the portion is changed gently. Since the deformation of the chassis frame can be carried out by the entire part, it has the effect of preventing stress concentration and improving the durability of the cross member.

  Preferably, in the present invention, the height h of the vertical wall of the portion of the cross member where the reinforcing flange is disposed is lower than the height H of the portion of the vertical wall alone, The connecting portion at the edge to the reinforcing flange tip may be formed so as to smoothly change from vertical to horizontal.

By adopting such a configuration, the height h of the vertical wall of the portion where the reinforcing flange is disposed is made lower than the height H of the portion of the vertical wall alone, thereby reducing the difference in the cross-sectional rigidity between the two and the vertical wall. Since the connecting part at the edge from the wall to the tip of the reinforcing flange is formed to smoothly change from the vertical to the horizontal direction, the change in the cross-sectional rigidity of the connecting part becomes gentle, and the deformation absorption range for side rail torsion And the deformation due to the twist from the side rails is easily absorbed by the entire cross member, thereby having the effect of preventing local stress concentration.
Further, by reducing the height h of the vertical wall, the weight and material cost can be reduced.

  Preferably, in the present invention, a mounting flange disposed at an end portion in the vehicle width direction of the cross member and bent rearward in the front-rear direction along the web surface of the side rail is attached to a seat for mounting the web surface and the tow hook. It is good to pinch with.

With such a configuration, the mounting flange of the cross member is sandwiched between the side rail web and the mounting seat of the tow hook, so that the load due to the torsion of the side rail is affected by the mounting hole of the mounting flange and the mounting hole of the tow hook. It has the effect of being able to reduce the stress generated in each mounting hole by being dispersed in both.
On the other hand, the force applied to the tow hook by towing the vehicle, etc., exerts a force in the direction parallel to and perpendicular to the side rail web surface, but the cross member mounting flange reinforces the side rail web surface. It also has the effect of acting as a member.

According to the present invention, since the reinforcing flange bent in the vehicle front-rear direction is arranged on either the upper side or the lower side, weight and material costs can be reduced.
In addition, since the bent connection portion between the edge of the vertical wall and the edge of the reinforcing flange in the vehicle width direction is smoothly changed, the change in cross-sectional rigidity of the portion changes gently. Since the deformation can be carried out by the entire part, the stress concentration is prevented and the durability of the cross member is improved.
Further, since the mounting flange of the cross member is sandwiched between the side rail web and the traction hook mounting seat, it has an effect as a reinforcing member for the side rail web surface.

These show the schematic plan view of the rear part of the chassis frame for trucks concerning embodiment of this invention. These show the schematic perspective view of the cross member concerning embodiment of this invention. These show the front view which concerns on embodiment of this invention, and the expanded view of the 1st reinforcement flange. Shows a cross-sectional view taken along the line XX in FIG. These show the joint structure figure of the cross member and side rail concerning the embodiment of the present invention. Shows a view in the direction of arrow Y in FIG. (A) is a schematic diagram of a cross member according to the prior art, and (B) is a detailed diagram of a single product of a cross beam (corresponding to the cross member of the present application). Fig. 2 shows a structure for attaching a tow hook according to the prior art.

Hereinafter, the present invention will be described in detail with reference to embodiments shown in the drawings.
However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention only to specific examples unless otherwise specifically described. Only.

  FIG. 1 is a schematic plan view of a rear portion of a chassis frame 1 for a truck according to an embodiment of the present invention. The chassis frame 1 has a right side rail 2 that is spaced in the vehicle width direction and extends in the vehicle front-rear direction. An intermediate cross member 4 and a rear cross member 5 which extend in the vehicle width direction between the left side rails 3 and are fixed to the left and right side rails 2 and 3 at both ends are ladder-like with a space in the front-rear direction. Is formed.

2 is a perspective view of the rear cross member 5 according to the embodiment of the present invention, FIG. 3 is a developed shape view of the reinforcing flange, and FIG. 4 is a sectional view taken along the line XX of FIG.
At both ends of the vertical wall 51 of the rear cross member 5 in the vehicle width direction, mounting flanges 52 that are attached to the web surfaces 21 of the left and right side rails 2 and 3 are disposed. The mounting flange 52 is bent rearward along the web surface 21 (see FIG. 5) of the left and right side rails 2 and 3. At the upper edge of the vertical wall 51, as shown in a developed view of the reinforcing flange 54 by a two-dot chain line in FIG. 3, the front end portion 541 of the reinforcing flange 54 is bent in a substantially horizontal state toward the rear of the vehicle. Yes. The height h of the vertical wall 513 in the bent portion is lower than the height H of the vertical wall 512 in the portion only of the vertical wall. (Refer to FIG. 3 and FIG. 4) In the connection portion E between the vehicle width direction edge 542 of the reinforcing flange 54 and the upper edge 511 which is the edge of the vertical wall 51, the upper edge 511 of the vertical wall 51 faces upward (vertical direction). To the horizontal direction of the front end portion 541 of the reinforcing flange 54, and is formed in a curved shape so as to follow the edge 542 in the vehicle width direction of the reinforcing flange 54. (See Figure 4)
In this embodiment, the reinforcing flange 54 is provided on the upper edge 511 side of the vertical wall 51. However, even if the reinforcing flange 54 is provided on the lower edge side of the vertical wall 51, it is easy to obtain the same effect.

  This is because the height h of the vertical wall 513 of the portion where the reinforcing flange 54 is disposed is made smaller than the height H of the vertical wall 512 of the portion of the vertical wall 51 alone, thereby reducing the difference in both section rigidity, Since the end edge of the connecting portion E from the vertical wall 51 to the distal end portion 541 of the reinforcing flange 54 is formed so as to smoothly change from the vertical to the horizontal direction, the cross-sectional rigidity change of the connecting portion E becomes gentle, and the left and right sides The range of deformation absorption with respect to the torsion of the rails 2 and 3 is increased, and there is an effect of preventing local stress concentration.

  Furthermore, since the reinforcing flange 54 bent in the longitudinal direction of the vehicle is arranged on either the upper side or the lower side with respect to the conventional cross member having a U-shaped cross section, the weight and material cost can be reduced.

The mounting flanges 52 disposed at both ends of the rear cross member 5 have a substantially L-shaped outer diameter as shown in FIGS. 4 and 6, and are attached to the web surfaces 21 of the side rails 2 and 3. Two holes 521 are formed on the bottom side and one on the upper side.
The left mounting flange 52 is fastened to the inner web surface 21 of the left side rail 3 by bolts 7, washers 8 and nuts 9 as fastening members.
Further, the right mounting flange 52 is bolted to the inner web surface 21 of the right side rail 2 by the mounting seat 61 of the pulling hook 6 through two mounting holes 521 drilled on the bottom side. 7, and is fastened by a washer 8 and a nut 9. One mounting hole 521 drilled on the upper side is fastened to the web surface 21 inside the side rail 2 by bolts 7, washers 8 and nuts 9.

This is because when the traction force is applied to the traction hook 6 by the traction rope 62, there is a phase difference in the vehicle width direction between the operation point of the traction rope 62, the traction force application portion of the traction hook 6 and the attachment portion to the side rail 2. Therefore, a pressing force in a direction perpendicular to the web surface 21 of the side rail 2 acts, but an attachment flange 52 is interposed between the web surface 21 and the traction hook 6. It has an effect as a reinforcing plate.
The acting force in the vehicle longitudinal direction of the traction hook 6 is arranged in the L-shape of the attachment flange 52 in addition to the two attachment holes 521 arranged in the portion sandwiched between the traction hook 6 and the web surface 21. The stress generated in each mounting hole 521 is reduced by being dispersed on the web surface 21 of the side rail 2 through fastening members such as bolts fastened to one mounting hole 521 drilled on the upper side of the three places. It has an effect that can be done.

According to the present embodiment, the rear cross member 5 disposed at the rear end portions of the left and right side rails 2 and 3 has a vertical wall 51 extending in the vehicle width direction, and either the upper side or the lower side of the vertical wall 51. And the height h of the vertical wall 513 where the reinforcing flange 54 is formed is made lower than the height H of the vertical wall 512 of the vertical wall only portion. In addition to reducing the difference in cross-sectional rigidity between the portion where the reinforcing flange 54 is formed and the vertical wall 512 of the vertical wall only portion, the bent connection portion between the end edge of the vertical wall 51 and the front end portion 541 of the reinforcing flange 54 Since the structure is such that E is smoothly changed, the entire rear cross member 5 absorbs deformation due to torsion of the left and right side rails 2 and 3, and the stress concentration portion is eliminated. Has the effect of reducing .
Further, since the mounting flange 52 is interposed between the web 21 of the right side rail 2 and the mounting seat 61 of the tow hook 6 in the tow hook mounting portion, the mounting flange 52 is located on the side against the acting force of the tow hook 6. It has an effect as a reinforcing plate of the rail 2.

  The present invention can be applied to a ladder-type chassis frame that can be flexibly deformed against torsional deformation of a vehicle to prevent generation of high stress and reduce weight and cost.

DESCRIPTION OF SYMBOLS 1 Chassis frame 2 Right side rail 3 Left side rail 5 Rear cross member 6 Tow hook 21 Web surface 51 Vertical wall 52 Mounting flange 54 Reinforcement flange 61 Mounting seat 511 Upper edge 521 Mounting hole 541 Tip part 542 Car width direction edge E Connection Part

Claims (3)

A pair of left and right side rails arranged in the vehicle width direction, each extending in the vehicle front-rear direction, and extending between the pair of left and right side rails in the vehicle width direction, both ends thereof being coupled to the side rail. In the vehicle chassis frame structure having a plurality of cross members,
The cross member disposed between the rear end portions of the pair of side rails has a vertical wall extending in the vehicle width direction, and a vehicle front-rear direction at an intermediate portion of either the upper side or the lower side of the vertical wall. A vehicle having a bent reinforcing flange, and smoothly changing the bent connecting portion between the edge of the upper or lower side of the vertical wall and the edge of the reinforcing flange in the vehicle width direction. Chassis frame structure.   The height h of the vertical wall of the portion where the reinforcing flange of the cross member is disposed is lower than the height H of the portion of the vertical wall only, and the end from the vertical wall to the tip of the reinforcing flange 2. The chassis frame structure for a vehicle according to claim 1, wherein the connecting portion of the edge is formed so as to smoothly change from a vertical direction to a horizontal direction.   A mounting flange disposed at an end portion in the vehicle width direction of the cross member and bent rearward in the front-rear direction along the web surface of the side rail is sandwiched between the web surface and a mounting seat of the tow hook. The chassis frame structure for a vehicle according to claim 1.

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