JPH10236342A - Under-frame structure of cab - Google Patents

Abstract

PROBLEM TO BE SOLVED: To offer an under-frame structure of a can to protect the occupants by forming grooves at the two inside corners of the undersurface of an underframe rear mating with a projection on a head pan, preventing generation of a booming sound through heightening of the resonance frequency of this part, furnishing a part reinforced with a reinforcement near the grooves, causing deformation in the part with the grooves and projections in the event of collision, lessening the deformation of the under-frame, and securing the space for the occupants. SOLUTION: A reinforcement 4 is attached to near the boundary between the c-part and d-part of an underframe rear 3 so as to heighten the stiffness of the part, and grooves 5 are formed at the two inside corners of the undersurface of the d-part. The bending stiffness of the cross-section of the under-frame rear 3 formed from the grooves 5 or the groove 5 and projection 6 is smaller than that of the part reinforcement with the reinforcement 4. Therefore, folding occurs at the part with the grooves 5, which allows suppressing the deformation of the under-frame rear 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an underframe structure for supporting a cab of a cab-over type truck, and more particularly to a cab underframe structure for improving occupant protection in a collision or the like.

[0002]

2. Description of the Related Art FIG. 9 shows a general cab-over type truck 13. The truck 13 has a cab 14 and a carrier 15 disposed behind the cab 14. The floor of the cab 14 has a step in the front-rear direction due to a layout related to an engine and a bed.
That is, as shown in FIG. 10, a floor panel 9 of a cab 14 and a bed pan 10 for mounting a bed and the like.
Are supported by an underframe 1 having a U-shaped cross section having an opening on the upper side.

The under frame 1 comprises an under frame front 2 arranged substantially on the front side and an under frame rear 3 connected to the rear. The under frame front 2 includes a front horizontal portion 2a (portion indicated by a), and a front rising portion 2b (indicated by b) which rises inclining from the rear and extends horizontally rearward from the rising end. Further, the rear frame rear 3 is connected to the rear end of the front rising portion 2b and rises rearward to be inclined rearward and rises up (shown by c).
And a rear horizontal portion 3b (denoted by d) extending substantially horizontally rearward from the rising end. In addition,
As shown in FIG. 10, the front horizontal portion 2a is
6 and a portion for supporting each component related to a brake (not shown), a front rising portion 2b and a rear rising portion 3
a corresponds to a portion on which the seat 17 is mounted, and the rear horizontal portion 3
b corresponds to a portion on which a bed (not shown) and the like are mounted. Further, as shown in FIG. 9, a door beam 18 for reducing deformation at the time of collision is arranged on the cab 14 along the front-rear direction. Further, as shown in FIG. 10, a reinforcing member 19 for reinforcing the under frame front 2 is fixed to the under frame front 2 side.

When an impact force F acts from the front side as shown in FIG. 11 at the time of collision with the conventional cab 14 having the above-described structure, the underframe 1 moves to the boundary 20 between the a and b portions and the c portion. Local pressure is applied to the boundary 21 between
It deforms back and forth and collapses. In addition, the high-weight carrier 15 moves forward due to the inertial force at the time of collision, hits the back panel 22 of the cab 14 and presses forward. Under frame rear 3 c
Comparing the part and the d part, the bending rigidity of the part d is
Since the stiffness is higher than the bending rigidity of the boundary 21 of the part, the cab 14 is ultimately greatly deformed in the front-rear direction from the position indicated by the two-dot chain line to the position indicated by the solid line, and the occupant space (indicated by M) between the seat 17 and the steering 16 And the protection of the occupants becomes insufficient.

There are many known techniques for solving the above problems. For example, Japanese Utility Model Registration No. 30021818 (Japanese Utility Model Application No. 6-5524) and Japanese Patent Application Laid-Open No. Hei 5-11225.
No. 4 gazette. Utility Model Registration No. 30021818
The “cab-over-type truck cab floor structure” disclosed in Japanese Patent Application Laid-Open Publication No. H11-163873 has an upper protrusion (11) formed on the upper surface of a bed pan (4a) and an underframe (1) opposed to the upper protrusion (11). ) Is formed with a lower convex portion (1c) penetrating the bottom wall (1b) along the vehicle width direction. By forming the upper convex part (11) and the lower convex part (1c), the bending rigidity of the boundary 21 between the c part and the d part shown in FIG. ) Is higher than the bending rigidity of the portion, and the underframe (1) is bent at the upper convex portion (11) and the lower convex portion (1c) as shown in FIG. Therefore, the occupant space (denoted by M) is shown in FIG.
Is larger than the occupant space M shown in FIG.

Japanese Unexamined Patent Publication No. 5-112254 discloses an "automobile body structure" in which a body frame supporting a floor panel (1) is a rear frame (10) as a main frame and a sub-frame fitted inside the rear frame (10). (30), a notch (15) of a low-rigidity portion is formed in the rear frame (10), and a notch of the low-rigidity portion that merges with the notch (15) in the event of a collision in the subframe (30). (3
5), the bending rigidity at the time of collision is reduced, and the notches (15) and (35) are greatly deformed at the time of impact to reduce the impact force and secure the occupant space. .

[0007]

The floor structure disclosed in Japanese Utility Model Registration No. 30021818 is effective in securing the occupant space M as described above, but has the following problems. is there. Vibration transmitted from an engine or the like and vibration accompanying the passage of exhaust sound and intake sound are transmitted to the cab. Of these, the most from the engine and the cab vibrates significantly at low rotations. With respect to the vibration of the cab, a low-rigidity portion such as a back panel resonates and vibrates greatly, and the rigidity of the underframe that supports the cab also has a considerable effect. That is, as described above, the upper convex portion (11) and the lower convex portion (1c) of the underframe (1),
In particular, since the lower convex portion (1c) is formed in a shape that greatly reduces the bending rigidity of the portion, the resonance frequency of this portion is low, and resonates with the vibration of the engine or the like at low rotation. For this reason, the cab shakes greatly, and a so-called muffled sound is generated in the vehicle interior. This muffled sound is a squeaking sound and gives the occupant a discomfort.

On the other hand, in the vehicle body structure disclosed in Japanese Patent Application Laid-Open No. 5-112254, since the notch (15) and the notch (35) do not unite during normal operation, the bending rigidity of the rear frame (10) is high, and It is not a cause. However, at the time of collision, the notch (15) and the notch (3)
The combination with 5) is not always performed smoothly,
There is a problem of lack of stability.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and it is possible to eliminate the generation of muffled noise, secure an occupant space at the time of a collision or the like, and implement a cab that is relatively simple and inexpensive to implement. An object is to provide an underframe structure.

[0010]

SUMMARY OF THE INVENTION In order to achieve the above objects, the present invention provides an underframe front having a U-shaped cross section having an opening at an upper portion, and an underframe front connected to the underframe front and having an upward opening. And an underframe comprising an underframe rear extending substantially horizontally from the rising end and extending rearward from the rising end, and a floor panel and a bed pan mounted on the underframe front and the underframe rear. A reinforcement that reinforces the underframe rear is fixed near a boundary between a rising portion of the underframe rear and a horizontal portion extending substantially horizontally rearward from the rising portion, and a reinforcement for the underframe rear is fixed. U
The cab has an underframe structure in which concave grooves are formed at both corners at the bottom of the U-shaped cross section. More specifically, a convex portion having an appropriate length is formed in a vehicle width direction on an upper surface side facing the concave groove of the horizontal portion of the bed pan, and the convex portion and / or the concave groove are formed. The bending stiffness of the cross section including the above is formed to be lower than the bending stiffness of the cross section of the reinforce portion.

A groove is formed in the underframe below the bed pan, but the groove is formed only at both corners, and the rigidity of this portion is relatively high, and the resonance frequency deviates from the muffled sound. . Reinforcing reinforcement is fixed at the boundary between the horizontal portion and the rising portion, and this portion has higher bending rigidity than the concave groove portion. Therefore, at the time of collision, only the concave groove portion in the bed portion is bent, and the boundary is not deformed, so that the occupant space can be secured. In addition,
Even when the convex portions and the concave grooves are formed, by giving the same degree of bending stiffness as described above, it is possible to enhance both the rigidity of the underframe and the effect of preventing deformation at the time of collision.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a cab underframe structure of the present invention will be described below in detail with reference to the drawings. As shown in FIG. 1, the underframe 1 includes an underframe front 2 and an underframe rear 3 connected thereto. The under frame rear 3 is fitted and fixed behind the under frame front 2,
For the sake of explanation, the structure is as follows. That is,
The under frame front 2 is composed of a front horizontal portion 2a (portion a) and a front rising portion 2b (portion b) which rises inclining from the rear end of the front horizontal portion 2a and extends substantially horizontally from the rising end. The frame rear 3
A rear rising portion 3a (portion c) which is connected to the front rising portion 2b and rises obliquely rearward, and is formed from a rear horizontal portion 3b (portion d) extending substantially horizontally rearward from the rising end. You. The underframe front 2 and the underframe rear 3 both have a U-shaped cross section having an opening 8 above.

The floor panel 9 has openings 8 on the a and b portions of the underframe front 2 of the pair of underframes 1 and 1 and the c portion of the underframe rear 3 which are juxtaposed at appropriate intervals. And placed on a bed pan 10
Is mounted on the d portion of the underframe rear 3 with its opening 8 closed. In addition, a flange 11 is provided at a contact portion of the underframe 1 with the floor panel 9 and the bed pan 10.
Is formed.

As shown in FIGS. 1 and 2, the underframe 1 of the present invention is characterized in that a reinforce 4 and a concave groove 5 are provided. Further, a feature is that the convex portion 6 is formed on the upper surface side of the bed pan 10. Hereinafter, these structures and the like will be described in detail.

As shown in FIG. 3, the reinforcement 4 is arranged from the portion c to the portion d of the rear frame rear 3, and
It is fixed to the upper surface of the bottom 7 of the underframe rear 3. The reinforce 4 may have a flat plate shape as shown by a solid line in FIG. 4 or may have a cross-sectional shape having flange portions 12 on both sides of the flat plate portion as shown by a dotted line.
In addition, the flange portions 12 are fixed to the inside of both side surfaces of the underframe rear 3. By appropriately setting the thickness and shape of the reinforce 4, the bending rigidity at the boundary between the portion c and the portion d increases.

On the other hand, as shown in FIGS. 3 and 5, a concave groove 5 is formed in the d portion of the underframe rear 3. Groove 5
As shown in FIG. 5, the lower frame rear 3 has a shape in which both corners of the bottom portion 7 are depressed inward. Therefore,
The bottom 7 without the groove 5 is kept in its conventional shape.

As shown in FIGS. 3 and 5, a bed pan 10 fixed to the upper surface of the d portion of the underframe rear 3 is provided.
A convex portion 6 is formed on the upper surface of. The convex portion 6 is formed at a position facing the concave groove 5 and, as shown in FIG. 1, is formed by an appropriate length along the vehicle width direction. Here, the bending rigidity in the cross section including the concave groove 5 and the convex part 6 is the reinforcement 4
Is lower than the bending rigidity of the portion of the underframe rear 3 to which the lower frame 3 is fixed. Further, since the concave groove 5 is formed only at both corners of the under frame rear 3, the bending rigidity of this portion is higher than that shown in the conventional utility model registration No. 3002918, and the resonance frequency is also high.

Next, the deformation of the cab underframe structure of the present invention at the time of collision will be described. FIG. 6 shows the cab 14 before collision and the underframe 1 supporting the same. Reinforces 4 are fixed at the boundaries between the c-portion and the d-portion of the underframe rear 3, and concave grooves 5 are formed at both corners on the lower surface of the d-portion of the underframe rear 3. Further, a convex portion 6 is formed at a position facing the concave groove 5 of the bed pan 10.

When the impact force F acts on the cab 14 in the state shown in FIG. 6 from the front, as shown in FIG. 7, the front side of the cab 14 is first dented. Along with this, the boundary 20 between the portions a and b of the underframe front 2 is bent. However, the boundary 2 between the portions c and d of the underframe rear 3
1 is reinforced by the reinforce 4, the boundary 21 is hardly deformed and the b of the underframe front 2
It moves only slightly upward with the bending of the part.

Next, as shown in FIG. 8, when the inertial force P from the loading platform 15 acts on the back panel 22, the portions of the d-shaped groove 5 and the convex portion 6 of the underframe rear 3 where the bending rigidity is low are reduced. Bend. However, the boundary 21 between the part c and the part d of the reinforce 4 hardly deforms. As described above, the overall deformation of the underframe 1 is reduced, and as shown in FIG. 8, a relatively large occupant space M can be secured, and the occupant can be protected.

Further, as described above, since the portion where the concave groove 5 is formed is formed with higher rigidity than the conventional one in which the muffled sound is generated, the resonance frequency of this portion is high, and the muffled sound is generated. Is prevented. Further, the underframe structure of the cab according to the present invention is a relatively simple one that simply reinforces the underframe with the reinforce 4 and forms the concave groove 5, and can be implemented at low cost. Also, the present invention can be applied to existing vehicles.

[0022]

【The invention's effect】

1) According to the cab underframe structure according to claims 1 and 3 of the present invention, the bending stiffness of the portion reinforced by the reinforce is higher than the bending stiffness of the portion in which the concave groove is formed, so that, for example, at the time of collision. Is bent from the concave groove portion, a relatively wide occupant space is secured, and the occupant can be protected. Further, since the concave groove is formed only at both corners, the resonance frequency is higher than that of the conventional one, and generation of a muffled sound is prevented. In addition, by providing the underframe with the reinforcement, the mounting rigidity of a floor panel or the like as a noise shutter panel can be improved as compared with the related art. 2) According to the cab underframe structure of the second aspect of the present invention, by forming a convex portion on the bed pan side at a position facing the concave groove of the underframe, the resonance frequency at which a muffled sound is generated can be obtained. Can also have a higher resonance frequency.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a structure of an underframe of the present invention and a floor panel, a bed pan and the like mounted on the underframe.

FIG. 2 is a partial perspective view showing a structure of an underframe rear of the present invention.

FIG. 3 is a partial side view of the underframe rear of the present invention.

FIG. 4 is a sectional view taken along line AA of FIG. 3;

FIG. 5 is a sectional view taken along line BB of FIG. 3;

FIG. 6 is a schematic diagram showing the shapes of a cab and an underframe before a collision according to the present invention.

FIG. 7 is a schematic diagram showing a deformed state of a cab and an under frame in an early stage of a collision.

FIG. 8 is a schematic view showing a deformed state of a cab and an under frame in a late stage of a collision.

FIG. 9 is a side view of a conventional cab-over type truck vehicle.

FIG. 10 is a side view showing a general structure of a conventional cab and underframe before collision.

FIG. 11 is a schematic view showing a deformed state of the cab and the under frame shown in FIG. 10 in a late stage of collision.

[Explanation of symbols]

 Reference Signs List 1 under frame 2 under frame front 2a front horizontal portion (a portion) 2b front rising portion (b portion) 3 under frame rear 3a rear rising portion (c portion) 3b rear horizontal portion (d portion) 4 reinforce 5 concave groove 6 convex Part 7 Bottom part 8 Opening part 9 Floor panel 10 Bed pan 11 Flange 12 Flange part 13 Truck car 14 Cab 15 Carrier 17 Seat 20 Boundary 21 Boundary 22 Back panel

Claims (3)

[Claims] 1. An underframe front having a U-shaped cross section having an opening at an upper portion thereof, and connected to a rear portion thereof. The underframe front rises inclining upward, and extends rearward along a substantially horizontal direction from a rising end. An underframe comprising an underframe rear and a floor panel and a bed pan mounted on the underframe front and the underframe rear, wherein the underframe rear includes a rising portion and a rising portion. Reinforcements for reinforcing the underframe rear are fixed near the boundary with the horizontal portion extending substantially horizontally rearward, and concave grooves are formed at both corners of the bottom of the U-shaped cross section of the horizontal portion. A cab underframe structure, characterized in that: 2. The cab according to claim 1, wherein a convex portion having an appropriate length is formed in a vehicle width direction on an upper surface side of the bed pan opposite to the concave groove of the horizontal portion. Under frame structure. 3. The bending stiffness of a cross section including the convex portion and / or the concave groove is formed to be lower than the bending stiffness of a cross section of a portion of the reinforce. Cab under frame structure.