JP4766388B2 - Cab back cross member - Google Patents

Description

  The present invention relates to a cab back cross member that is disposed between a cab under member and a loading platform and is attached to a chassis frame.

  A freight vehicle (hereinafter referred to as a cab over truck) having a cab supported at the front part of the chassis frame and a cargo bed supported at the rear part of the chassis frame, and in which the seating position of the driver in the cab is located in front of the engine. Kinetic energy at the time of collision (hereinafter referred to as frontal collision) against a rigid wall (hereinafter referred to as frontal collision) is absorbed mainly by the front end of the strong chassis frame hitting the barrier and effectively deforming. Thus, a living space (hereinafter referred to as a cab living space) is secured in the upper cab, and safety is maintained.

  A vertical joist extending in the vehicle front-rear direction is fixed to the bottom surface of the loading platform disposed behind the cab. The vertical joists are mounted on the upper surface of the chassis frame and fixed by U-bolts. Moreover, since there is a possibility that the fixing in the longitudinal direction of the vehicle body may be insufficient with only the U bolt, a loading platform stopper that spans the chassis frame and the vertical joist is provided. The loading platform stopper is fastened and fixed to the chassis frame and the vertical joist with bolts, and complements the fixing with the U bolts in the longitudinal direction of the vehicle body.

  However, the fixed strength of the loading platform with respect to the chassis frame is set on the assumption that a load of a predetermined weight is loaded on the loading platform, so that the loading load is loaded to the upper limit of the allowable weight on the loading platform. When a frontal collision occurs, it is difficult to completely suppress the forward movement of the loading platform.

  In order to eliminate such inconvenience, a cab back cross member that protrudes upward from the chassis frame is provided between the cab (cab under member) and the loading platform, and the loading platform that moves forward during a frontal collision contacts the cab back cross member. It is known that the movement of the cargo bed is restricted by the bending rigidity of the cab back cross member.

JP-A-8-216934

  However, in the structure in which the lower end portion of the cab back cross member is simply connected to the chassis frame by fastening the bolt, the load at the time of a frontal collision is likely to concentrate on the connecting portion (bolt or the like) between the cab back cross member and the chassis frame. Therefore, the shear failure of the bolt occurs, the connecting portion is easily damaged, and it is difficult to effectively restrict the movement of the cargo bed using the bending rigidity of the cab back cross member. In general, since the cab is supported from below by a cab under member having a bent portion, when an impact force due to a frontal collision acts on the cab under member, the cab under member is centered on the bent portion. In such a case, the entire cab is deformed and it is difficult to secure a cab living space.

  On the other hand, when there is a height difference between the chassis frame of the preceding vehicle and the chassis frame of the cab overtrack, if the cab over track collides with the preceding vehicle (hereinafter referred to as a rear-end collision), the impact force due to the rear-end collision directly acts on the front part of the cab. Therefore, the cab moves toward the rear of the vehicle. However, if the moving cab comes into contact with the cab back cross member, the rearward movement of the cab is remarkably restricted, so that the cab may be deformed toward the rear of the vehicle around the rear-end collision location, and the cab living space may be reduced. There is. Further, when the impact force due to the rear-end collision is applied to the cab under member, the cab under member is bent and deformed similarly to the case of the frontal collision, and it may be difficult to secure a cab living space.

  Therefore, an object of the present invention is to provide a cab back cross member that can suppress cab deformation and further secure a cab living space at the time of a frontal collision or rear-end collision of a cab overtrack.

  In order to achieve the above object, the present invention is arranged between a cab under member that supports a cab from below on the left and right chassis frames extending in the vehicle front-rear direction and a cargo bed located at the rear of the cab in the vehicle. The cab back cross member includes a horizontal portion, two vertical portions, an easily deformable portion, and an energy absorbing member. The horizontal portion extends along the vehicle width direction. The two vertical portions bend downward from both sides in the vehicle width direction of the horizontal portion, and the lower ends thereof are coupled to the two chassis frames, respectively. The easily deformable portion is formed in at least one of the two vertical portions, and stress is concentrated when a load in the vehicle longitudinal direction is input to the vertical portion. The energy absorbing member is provided in the easily deformable portion, and deforms with the deformation of the easily deformable portion to absorb energy when a load from the rear of the vehicle is input to the vertical portion.

  In the above configuration, the cab back cross member disposed between the cab under member and the cargo bed has two vertical portions coupled to the chassis frame. The vertical portion is formed with an easily deformable portion where stress is concentrated when a load in the vehicle front-rear direction is input, and when the load from the rear of the vehicle is input to the vertical portion, An energy absorbing member that is deformed along with the deformation of the deforming portion and absorbs the input energy is provided.

  For this reason, for example, when an impact force (load from the rear of the vehicle) acts on the cab back cross member due to the forward movement of the loading platform due to a frontal collision of the vehicle, the easily deformable portion formed in the vertical portion Since the stress is concentrated, the cab back cross member is bent and deformed toward the front of the vehicle centering on the easily deformable portion, and the energy absorbing member is deformed along with the deformation of the easily deformable portion, and the impact force (energy) from the loading platform. To absorb. That is, since the impact force from the loading platform is effectively absorbed by the deformation of the energy absorbing member, the impact force acting on the coupling portion between the cab back cross member and the chassis frame can be reduced. Accordingly, it is possible to prevent the coupling portion between the cab back cross member and the chassis frame from being damaged, and to effectively prevent the forward movement of the cargo bed by utilizing the deformation of the energy absorbing member. Further, in this case, since the impact force from the cargo bed hardly acts on the cab under member, it is possible to suppress deformation of the entire cab due to bending deformation of the cab under member.

  On the other hand, when the mounting height of the chassis frame of the vehicle is lower than the chassis frame of the front vehicle, the impact force (load from the front of the vehicle) due to the rear collision is caused by the rearward movement of the cab due to the rear collision of the vehicle to the front vehicle. When acting on the back cross member, the cab back cross member bends and deforms toward the vehicle rear side around the easily deformable portion where stress is concentrated. That is, since the rearward movement of the cab is allowed by the deformation of the cab back cross member, the impact force acting on the cab under member can be reduced. Accordingly, since the impact force due to the rear-end collision is unlikely to act on the cab under member, the deformation of the entire cab due to the bending deformation of the cab under member can be suppressed as in the case of a frontal collision.

  Thus, according to the above configuration, the impact force on the cab can be reduced both in the frontal collision and in the rear-end collision, so that the deformation of the cab can be effectively suppressed and the cab living space can be secured.

  In addition, an energy absorbing member that absorbs the impact force of the cab back cross member when the cab back cross member is bent toward the front of the vehicle at the time of a frontal collision, and an easy deformation that allows the cab back cross member to be bent toward the rear of the vehicle at the time of a rear-end collision. Since it is a separate body from the section, the bending strength of the cab back cross member can be individually set according to each collision scene. Therefore, since the bending strength of the cab back cross member can be set as appropriate at each of the frontal collision and the rear-end collision, the cab living space can be ensured at any collision.

  Moreover, you may arrange | position an easily deformable part in the position lower than the lower end of the vehicle front side of a loading platform in a vehicle up-down direction.

  In the above configuration, the easily deformable portion is located below the loading point load input point to which the impact force from the loading platform (load from the rear of the vehicle) is input in the vertical portion, and between the cab back cross member and the chassis frame. It arrange | positions above a coupling | bond part. That is, when an impact force from the cargo bed is input to the cab back cross member due to a frontal collision of the vehicle, the cab back cross member is located on the front side of the vehicle centering on the easily deformable portion disposed below the load loading point. Since it bends and deforms well toward the surface, this impact force can be reliably absorbed by deformation of the energy absorbing member. Therefore, it is possible to efficiently absorb the impact force from the loading platform, so that the cab living space can be further secured.

  According to the present invention, the cab living space can be further ensured with a simple configuration because the deformation of the cab can be effectively suppressed both during the frontal collision and during the rear-end collision.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. 1 is a schematic side view of a cab overtrack of the present embodiment, FIG. 2 is an enlarged view of a portion II in FIG. 1, FIG. 3 is a cross-sectional view taken along arrow III-III in FIG. 5 is an enlarged view of the main part of FIG. 4, FIG. 6 is a perspective view of the cab back cross member, FIG. 7 is an enlarged side view of the main part showing the arrangement state of the cab back cross member, and FIG. 9 is a schematic side view showing a state, FIG. 9 is an enlarged side view of a main part showing a state at the time of a frontal collision, and FIG. In the figure, FR indicates the front of the vehicle, UP in the figure indicates the top of the vehicle, and arrows in FIGS. 9 and 10 indicate the direction of the load. Moreover, the left-right direction in the following description means the left-right direction in the state which faced the vehicle front.

  As shown in FIGS. 1 and 4, the cab overtrack 1 includes a chassis frame 2 extending in the vehicle front-rear direction on both sides in the vehicle width direction, a cab 3 supported from below on the front portion of the chassis frame 2, and a chassis. A loading platform 4 supported from below at the rear of the frame 2, a cab under member 31 that supports the cab 3 from below, and a cab back cross member 5 disposed between the cab under member 31 and the loading platform 4. ing.

  As shown in FIG. 1, the loading platform 4 is opposed to the front iron plate 6 disposed in the vehicle width direction behind the cab 3 through an appropriate gap, and from both ends of the front iron plate 6 in the vehicle width direction to the rear. And a rear gate 8 that opens and closes the rear ends of the rear plate 7 at the rear of the vehicle body, and forms a bottom surface of a rectangular housing space defined by the front iron plate 6, the upper plate 7 and the rear gate 8. And a vertical joist 10 fixed to the lower surface of the bottom plate 9 and extending in the front-rear direction on both sides in the vehicle width direction.

  As shown in FIGS. 2 and 3, the vertical joist 10 includes a bottom wall 11, side walls 12 and 13 extending upward from opposite ends of the bottom wall 11, and opposite directions from the upper ends of both side walls 12 and 13. And has a reverse hat-shaped cross-section with flanges 14 and 15 extending in a bent manner. Both flanges 14 and 15 are fixed to the lower surface of the bottom plate 9 of the loading platform 4, thereby forming a closed cross section between the vertical joists 10 and the bottom plate 9.

  The chassis frame 2 has a substantially rectangular shape including a bottom wall 17, side walls 18 and 19 that extend upward from both ends of the bottom wall 17, and an upper wall 20 that connects upper ends of both side walls 18 and 19. Has a closed cross section. The vertical joist 10 is placed on the chassis frame 2 with its bottom wall 11 in contact with the upper wall 20 of the chassis frame 2, and fixed on the chassis frame 2 by U bolts 21.

  Bolt insertion holes 22 are formed at the upper ends of both side walls 12 and 13 of the vertical joist 10, respectively. The U bolt 21 includes a bottom bar portion 23 inserted into the bolt insertion hole 22 and a side bar portion that is bent downward from both ends of the bottom rod portion 23 protruding outside the both side walls 12 and 13 of the vertical joist 10. 24, 25. The distal ends of the side bar portions 24 and 25 are inserted through the fixing plate 26 and hinged with the nut 27. By tightening the nut 27, the vertical joist 10 is fastened and fixed to the chassis frame 2 between the fixing plate 26 and the bottom bar portion 23 of the U bolt 21. Further, the vertical joist 10 and the chassis frame 2 are connected by a stopper member 28. The stopper member 28 is fastened and fixed to the vertical joists 10 and the chassis frame 2 by bolts 29 and nuts (not shown).

  As shown in FIG. 4, the cab under member 31 has a substantially U-shaped cross section and extends in the vehicle front-rear direction on both sides in the vehicle width direction below the cab 3. The cab under member 31 includes a front portion 32 disposed substantially horizontally on the front side of the vehicle, a bent portion 33 that is bent from the rear end of the front portion and extends obliquely upward of the vehicle, and a rear end of the bent portion 33. A rear portion 34 that bends and extends substantially horizontally toward the rear of the vehicle, and is fixed to the cab 3 by welding or the like in contact with the lower surface of the cab 3. . The front end of the front portion 32 is supported to be tiltable by a tilt shaft (not shown) of a front cab mount disposed at the front end of the chassis frame 2. The rear end of the rear portion 34 is detachably supported by a cab mount column (not shown) of a rear cab mount fixed to the chassis frame 2 via a lock mechanism (not shown).

  As shown in FIGS. 4 to 6, the cab back cross member 5 includes a cab back cross member main body 36 and an energy absorbing member 37, and is coupled to the chassis frame 2 via a mounting bracket 38.

  The cab back cross member main body 36 is formed of a pipe-like member, and includes a horizontal portion 39 extending in the vehicle width direction, two vertical portions 40 extending downward from both sides of the horizontal portion 39 in the vehicle width direction, and a vertical portion 40. And a notch (easily deformable portion) 41 to be formed. Further, the inner width between the lower end portions 42 of the two vertical portions 40 is set substantially equal to the interval along the vehicle width direction of the outer surface of the left and right chassis frames 2.

  As shown in FIG. 6, the notch 41 has a substantially U-shaped cross section (not shown) that opens from the side of the vertical portion 40 on the front side of the vehicle toward the rear of the vehicle, and a plate that has substantially the same shape as the opening. 43. The plate 43 is fixed to the cab back cross member main body 36 by welding the outer peripheral edge of the plate 43 with the opening closed from the front side of the vehicle. The notch 41 opens toward the front of the vehicle in a state where the cab back cross member main body 36 is fixed to the chassis frame 2 and is lower than the lower end 48 on the vehicle front side of the loading platform 4 in the vehicle vertical direction. It arrange | positions in a low position (refer FIG. 7). Thus, since the notch 41 is formed in the vertical part 40 of the cab back cross member main body 36, when a load in the vehicle vertical direction acts on the vertical part 40 above the notch 41, the notch 41. The cab back cross member main body 36 bends and deforms around the notch 41 as the load is input.

  As shown in FIGS. 4 and 5, the mounting bracket 38 has a substantially plate shape, and a concave portion along the outer surface shape of the cab back cross member main body 36 is bent at an intermediate portion thereof. A plurality of bolt insertion holes (not shown) are formed at predetermined positions on the side walls of the mounting bracket 38 and the chassis frame 2. The vertical portion 40 of the cab back cross member body 36 is inserted into the bolt insertion holes of the mounting bracket 38 and the chassis frame 2 with the lower end portion 42 sandwiched between the recess of the mounting bracket 38 and the outer surface of the chassis frame 2. Each bolt 46 is inserted, and a nut 47 is hinged and tightened to each bolt 46 to be fastened and fixed to the chassis frame 2.

  As shown in FIGS. 4 to 6, the energy absorbing member 37 is an EA material (energy absorber material) having energy absorbing characteristics, for example, high structural materials such as ordinary structural steel S45C and SAPH440, dual phase steel, and the like. And has a substantially semicircular cross section that can be fitted to the notch 41. The energy absorbing member 37 is fixed to the cab back cross member main body 36 by welding or the like only at the edge of the lower surface of the energy absorbing member 37 in a state where the energy absorbing member 37 is fitted to the notch 41.

  Next, the operation of the cab back cross member at the time of collision will be described with reference to FIGS. 1 and 7 to 10.

  As shown in FIG. 7, in the state before the collision, the cab back cross member 5 is substantially vertically upward from the surface of the upper wall 20 of the chassis frame 2 between the cab 3 (cab under member 31) and the loading platform 4. Protrusively.

  As shown in FIGS. 1 and 9, when the cab overtrack 1 collides frontally with the barrier surface 51, the kinetic energy is absorbed mainly by effectively deforming the front end of the strong chassis frame 2. At this time, since the chassis frame 2 is rapidly decelerated, the loading platform 4 starts moving forward. When the lower end 48 of the loading platform 4 hits and presses against the upper portion of the cab back cross member 5, an impact force (load) from the loading platform 4 acts on the cab back cross member 5.

  If the impact force acts on the upper part of the cab back cross member that does not have the notch 41 and the energy absorbing member 37, the lower end of the cab back cross member is coupled to the chassis frame 2 by the bolt 46. Therefore, an excessive impact force acts on the joint portion, and the bolt 46 is broken. In such a case, since the forward movement of the loading platform 4 is allowed, the loading platform 4 comes into contact with the rear portion of the cab 3 and an impact force from the loading platform 4 acts on the cab 3. At this time, when an impact force from the loading platform 4 acts on the cab under member 31 that supports the cab 3 from below, the cab under member 31 is bent upwardly around the bent portion 33 (see FIG. 4) of the cab under member 31. As a result, the entire cab 3 is deformed.

  On the other hand, in the cab back cross member 5 according to the present embodiment, when an impact force from the loading platform 4 acts on the upper part of the cab back cross member 5, stress concentrates on the notch portion 41 formed in the vertical portion 40. Therefore, the cab back cross member 5 is bent and deformed toward the vehicle front side with the notch 41 as the center. At this time, the energy absorbing member 37 is deformed in the compressing direction along with the deformation of the notch 41 and absorbs the impact force from the loading platform 4. That is, since the impact force from the loading platform 4 is effectively absorbed by the deformation of the energy absorbing member 37, the impact force acting on the coupling portion (bolt 46 and the like) between the cab back cross member 5 and the chassis frame 2 is reduced. be able to. Accordingly, it is possible to prevent the connecting portion between the cab back cross member 5 and the chassis frame 2 from being damaged, and to effectively prevent the forward movement of the cargo bed 4 by utilizing the deformation of the energy absorbing member 37. Further, in this case, since the impact force from the loading platform 4 hardly acts on the cab under member 31, it is possible to suppress deformation of the entire cab 3 due to bending deformation of the cab under member 31.

  On the other hand, as shown in FIGS. 8 and 10, when the mounting height of the chassis frame 2 of the cab overtrack 1 is lower than the chassis frame 53 of the front vehicle 52, if the cab overtrack 1 collides with the front vehicle 52, the cab Since the impact force due to the rear-end collision directly acts on the front portion of the cab 3, the cab 3 starts to move rearward and hits the cab back cross member 5 to be prevented from moving.

  If this impact force acts on the upper part of the cab back cross member that does not have the notch 41, the impact force acts on the cab under member 31 that supports the cab 3 from below. The cab under member 31 is bent upwardly with the bent portion 33 (see FIG. 4) as the center, and the entire cab 3 is deformed.

  On the other hand, in the cab back cross member 5 according to the present embodiment, when an impact force due to a rear-end collision acts on the cab back cross member 5, the cab back cross member 5 has a vehicle rearward centered on the notch 41 where stress is concentrated. Bend to the side. Moreover, since only the edge of the lower surface of the energy absorbing member 37 is joined to the plate 43 of the notch 41, the energy absorbing member 37 does not hinder the deformation of the notch 41. That is, since the rearward movement of the cab 3 is permitted by the deformation of the cab back cross member 5, the impact force acting on the cab under member 31 can be reduced. Therefore, even when the cab over track 1 collides with the forward vehicle 52, deformation of the entire cab 3 due to bending deformation of the cab under member 31 can be suppressed. The edge of the lower surface of the energy absorbing member 37 is fixed to the outer peripheral edge of the opening of the notch 41. For example, the front end of the energy absorbing member 37 or the edge of the upper surface is connected to the notch 41. It is also possible to fix to the outer peripheral edge of the opening.

  As described above, according to the present embodiment, since the impact force on the cab 3 can be reduced both in the frontal collision and in the rear-end collision, the deformation of the cab 3 is effectively suppressed and the cab living space is secured. Can be done.

  In addition, an energy absorbing member 37 that absorbs the impact force of the cab back cross member 5 when the cab back cross member 5 is bent toward the front side of the vehicle at the time of a frontal collision, and allows bending deformation of the cab back cross member 5 toward the rear side of the vehicle at the time of rear-end collision. Since the cutout portion 41 is a separate body, the bending strength of the cab back cross member 5 can be individually set according to each collision scene. Therefore, since the bending strength of the cab back cross member 5 can be set as appropriate at each of the frontal collision and the rear-end collision, the cab living space can be ensured at any collision.

  The notch 41 is below the loading point load input point where the impact force from the loading platform 4 is input in the vertical portion 40, and is a coupling portion between the cab back cross member 5 and the chassis frame 2 (such as a bolt 46). It is formed above. That is, when an impact force from the loading platform 4 is input to the cab back cross member 5 due to a frontal collision of the cab over track 1, the cab back cross member 5 has a notch 41 disposed below the loading platform load input point. Since it is favorably bent and deformed toward the front side of the vehicle as the center, this impact force can be reliably absorbed by the deformation of the energy absorbing member 37. Therefore, since the impact force from the loading platform 4 can be efficiently absorbed, the cab living space can be further secured.

  In the present embodiment, the shape of the energy absorbing member 37 is formed in a substantially semicircular cross section. For example, as shown in FIGS. 11A and 11B, the shape of the energy absorbing member is substantially columnar. It is also possible to form the cutout portion so as to have a substantially U-shaped cross section.

  As mentioned above, although the embodiment to which the invention made by the present inventor is applied has been described, the present invention is not limited by the discussion and the drawings that form part of the disclosure of the present invention according to this embodiment. That is, it should be added that other embodiments, examples, operation techniques, and the like made by those skilled in the art based on this embodiment are all included in the scope of the present invention.

It is a model side view of the cab overtrack of this embodiment. It is the II section enlarged view of FIG. FIG. 3 is a cross-sectional view taken along the line III-III in FIG. 2. It is a principal part perspective view of FIG. It is a principal part enlarged view of FIG. It is a perspective view of a cab back cross member. It is a principal part enlarged side view which shows the arrangement | positioning state of a cab back cross member. It is a model side view which shows the state immediately before the rear-end collision of a cab overtrack. It is a principal part enlarged side view which shows the state at the time of a frontal collision. It is a principal part enlarged side view which shows the state at the time of a rear-end collision. It is a perspective view which shows the other example of an energy absorption member.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Cab over track 2 Chassis frame 3 Cab 4 Loading platform 5 Cab back cross member 31 Cab under member 36 Cab back cross member main body 37 Energy absorption member 39 Horizontal part 40 Vertical part 41 Notch part (easy deformation part)
42 Lower end 48 Lower end

Claims (2)

A cab back cross member disposed between a cab under member that supports a cab from below on left and right chassis frames extending in the vehicle front-rear direction and a cargo bed located at the vehicle rear of the cab,
A horizontal portion extending along the vehicle width direction;
Two vertical portions that bend and extend downward from both sides in the vehicle width direction of the horizontal portion, and whose lower end portions are respectively coupled to the left and right chassis frames;
An easily deformable portion that is formed on at least one of the two vertical portions, and stress is concentrated when a load in the vehicle longitudinal direction is input to the vertical portion;
An energy absorbing member that is provided in the easily deformable portion and deforms with the deformation of the easily deformable portion to absorb energy when a load from the rear of the vehicle is input to the vertical portion;
A cab back cross member characterized by comprising: The cab back cross member according to claim 1,
The cab back cross member, wherein the easily deformable portion is disposed at a position lower than a lower end of a front side of the loading platform in a vehicle vertical direction.

Images