JPH0790799B2 - Chassis frame with packing box - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a chassis frame of a vehicle including a luggage box such as a truck.

(Prior Art) An ordinary truck is composed of a pair of left and right side rails extending in the longitudinal direction of the vehicle body and having a groove-shaped cross-section, and a plurality of rails arranged in the vehicle width direction and having both ends fixed to the side rails. Of the cross member, and a luggage box is mounted on the chassis frame via an intermediate member such as a vertical joist and a subframe, and is tightly fastened to the side rail by a fixing means such as a U bolt. ing.

A member having a groove-shaped or I-shaped cross-section is widely used for the cross member. In any case, the upper flange and the lower flange of the cross member have a plate thickness and a width in the vehicle body front-rear direction (hereinafter referred to as "width"). The rivets or bolts, which are sometimes referred to as flange widths), are formed to be substantially equal, so that the rivets or bolts that fasten these flanges to the side rails directly or indirectly via gussets are also arranged in substantially the same manner.

(Problems to be solved by the invention) When a vehicle such as a truck is used under severe conditions such as traveling at a high speed on a rough road having severe unevenness, a large torsion load acts on the chassis frame, A large stress may be generated in the cross member, especially near the joint with the side rail.

An undercarriage in which a pair of left and right side rails 10 each having a groove-shaped cross section as shown in the conceptual side view of FIG. 10 are fastened with rivets or bolts to both ends of a cross member 12 having a groove-shaped cross section. When a torsion test was performed on the frame 14, when the chassis frame 14 alone was used, the cross member
The upper and lower flanges 12u and 12l of the twelve are subjected to vehicle front-rear direction shearing forces having substantially equal magnitudes as indicated by arrows S _u and S _l in the figure, respectively, but shown in the conceptual side view of FIG. As described above, when the luggage box 18 is mounted on the undercarriage frame 14 via the vertical joists or the sub-frame 16 and is tightly fixed to the side rails 10 by the fixing means 20 such as U bolts,
As indicated by the arrow S _'u and S' _l in the figure, much larger vehicle body longitudinal direction of the shearing force than that of the upper flange 12u has been found to act on the lower flange 12l. This test result shows that in an ordinary truck undercarriage frame in which the packing box 18 is mounted on the undercarriage frame 14, the upper flange 12u and the lower flange 12l of the cross member 12 are arranged in a substantially same manner. The conventional configuration in which the side rails 10 are fastened to the side rails 10 by rivets or bolts is structurally unreasonable, and when the above-mentioned severe traveling is repeatedly performed, the rivets or the rivets that fasten the lower flange 12l to the side rails. There is a problem that defects in strength are likely to occur in the bolt group. When it is attempted to prevent damage to the rivet or the bolt group, or damage to the side rail or cross member plate material that cooperates therewith,
Conventionally, measures have been conventionally taken such as increasing the number of rivets or bolts to be used by interposing reinforcing plates as many as necessary in areas where strength is uncertain. However, there are disadvantages such as a decrease in effective load capacity and deterioration of fuel efficiency.

In view of the above circumstances, the present invention is provided with a luggage box in which the strength of the portions where the upper flange and the lower flange of the cross member are fastened to the side rails is made uniform to improve the durability and reduce the weight. The purpose is to provide a chassis frame.

(Terms) In this specification, the term "equivalent center of gravity" with respect to a plurality of rivets or bolts that fastens the upper and lower flanges of the cross member in the vehicle width direction to the side rails has the following meaning. is there. That is, in FIG. 9, the transverse elastic coefficients of an arbitrary number (two or more) of rivets or bolts R ₁ , R ₂ ... R _i ... R _n-1 , R _n are respectively G ₁ , G ₂ ... G
_i … G _n-1 , G _n , coordinate vector of each rivet or bolt
_{When 1} , _2, ... _i ... _n-1 , _n , the coordinate vector g of the equivalent center of gravity g is It is represented by.

(Means for Solving the Problems) A chassis frame with a luggage box according to the present invention was created to achieve the above object, and includes a pair of left and right extending in the vehicle body front-rear direction and having a groove-shaped cross-section. The crossrail is provided in the vehicle width direction and has a groove-shaped or I-shaped cross-section. The upper flange and the lower flange of the crossmember are connected to the siderail by a plurality of rivets or bolts. A cross comprising the chassis frame directly or indirectly fastened via a gusset, and a luggage box mounted on the chassis frame and fastened to the side rails by a fixing means such as a U bolt. The number of rivets or bolts for fastening the upper flange of the member to the side rail is n _u , the cross-sectional area of each rivet or bolt is A _ui , the rivet or bolt is R is the distance from the equivalent center of gravity g _u of the group to the center line of each rivet or bolt.
_ui , the number of rivets or bolts for fastening the lower flange of the cross member to the side rail is n _l , the cross-sectional area of each rivet or bolt is A _li , and the rivet or bolt group's equivalent center of gravity gl to each rivet or bolt. When the distance to the center line of the bolt is r _li , the rivet of the upper flange and the lower flange or the bolt group is It is characterized in that it is arranged so as to satisfy.

(Operation) According to the present invention, the rivets or the bolts for fastening the upper flange and the lower flange of the cross member to the side rails are arranged so as to satisfy the above expression, so that the strength of the fastening portion is equalized. With, and thus improved durability.

(Embodiment) An embodiment of the present invention will be specifically described below with reference to FIGS. First, in the first embodiment of the present invention shown in FIGS. 1 to 3, the chassis frame 14 includes a pair of left and right side rails extending in the vehicle front-rear direction and having a groove-shaped cross section.
10 and a large number of rivets 22 on the same rail 10w
Alternatively, groove-shaped gussets 24 fixed by bolts of substantially the same effect and upper flanges 24u and lower flanges 24l of the gussets are respectively provided with corresponding ends of upper flanges 12u and lower flanges 12l in the vehicle width direction. Multiple rivets 26u
And 26l or a cross-member 12 of grooved cross section fastened with substantially the same bolts.

As shown in the perspective view of FIG.
Upper flange 12u flange width bu and lower flange 12l
The flange width of bl is the shearing force acting on the upper flange and the lower flange when the chassis frame is twisted, as already described with respect to the chassis frame with the luggage box in FIG.
It is shaped to accommodate S _u ′ and S _l ′. In the illustrated example, the upper flange 12u and the lower flange 12l have the same plate thickness, but it is of course possible to change the plate thickness together with the flange widths bl and bu to adapt to the shearing forces S _u ′ and S _l ′. Is.

The upper flange 12u is shown with n _u = 4 rivets 26u
Is fastened to the upper flange 24u of the gusset 24, and the equivalent center of gravity of these rivets 26u group is gu. Meanwhile lower flange 12l is fastened to the lower flange 24l of the gusset 24 by the illustrated case n _l = 8 rivets 26l, rivets 2
The equivalent center of gravity of the 6l group is gl. The coefficients that represent the degree of suppression of the shearing force generated on each rivet are M _u (upper flange) and M _l
(Lower flange) , The rivet group 26u is arranged based on M _u so as to maintain necessary and sufficient strength against the shearing force S _u ′ acting on the upper flange 12u, and similarly. In represented, the rivet group 26l is disposed based on the M _l so as to retain sufficient strength in the need to shear forces S _l 'acting on lower flange 12l. The vehicle front-rear direction shearing force acting on the upper flange 12u and the lower flange 12l is the torsional rigidity of the chassis frame 14 itself, the torsional rigidity of the luggage box 18, and the constraint condition between the chassis frame 14 and the luggage box 18. Depending on the characteristics of each vehicle, the ratio between M _l and M _u is appropriately determined within the range of 1.2 ≦ M _l / M _u ≦ 5. If M _l / M _u is larger than 5, the bending buckling strength of both upper and lower flanges becomes too large when a vertical bending load is applied to the cross member.
In order to obtain the strength required for the upper flange of the cross member, the lower flange becomes large, which causes a problem that the weight increases, which impairs practicality.

By selecting the above M _l / M _u to an appropriate value of 1.2 or more and 5 or less, the strength of the rivet group of the upper flange 12u and the strength of the rivet group of the lower flange 12l are substantially equal to each other and there is no excess or deficiency. As a result, the durability and reliability of the joint between the cross member 12 and the side rail 10 can be effectively improved, and the same effect can be obtained when bolts are used instead of rivets. Can be accommodated. Further, as shown in the drawing, the flange widths bu and bl of the upper flange 12u and the lower flange 12l of the cross member 12 are set to have appropriate sizes according to the shearing forces acting on the respective flanges, so that the cross member itself is also There are benefits that can reduce weight.

Next, a second embodiment of the present invention shown in FIGS. 4 and 5 will be described. In this embodiment, the upper flange 12u of the cross member 12 similar to that of the first embodiment has the side rail 10
Are fastened directly to the upper flange 10u of the cross rail 12 with n _u (four in the illustrated case) rivets 26u or substantially the same bolts, and the lower flange 12l of the cross member 12 is connected to the lower flange 10l of the side rail 10. n _l (8 in the figure)
Rivets 26l or bolts of substantially the same effect.

Like the first embodiment, the shearing moment M _u rivets or bolts groups upper flange 12u, the ratio of the shear moment M _l rivets or bolts group lower flange 12l, 1.2
Within the range of ≦ M _l / _Mu ≦ 5, the shearing force S _u ′ acting on the upper flange and the lower flange in the vehicle front-rear direction is appropriately selected according to the torsional rigidity of the chassis frame 14 and the luggage box 18 and the like.
And S _l ′, the strength of each rivet or bolt group can be made appropriate without excess or deficiency, and as a result, the durability of the joint between the cross member 12 and the side rail 10 and The reliability can be improved.
Also, the flange width b _u of the upper flange 12 _{u of} the cross member 12
And a flange width bl of the lower flange 12l, by a dimensionally adapted to the shear force as the respective illustrated S _u 'and S _l', as in the first embodiment, weight reduction of the cross member 12 itself Can be achieved at the same time.

Further, FIGS. 6 and 7 show a third embodiment of the present invention,
In this embodiment, the webs of the two groove-shaped members are brought into contact with each other back to back and integrally joined by a large number of rivets 28 to form a cross member 12 having an I-shaped cross section, and an upper flange of the cross member is formed. The 12u are directly fastened to the upper flange 10u of the side rail 10 by n _u (four in the illustrated case) rivets 26u or bolts of substantially the same effect, and the lower flange 12l of the cross member 12 is fixed to the side rail 10. rivet 26l of n _l pieces beneath flange 10l of (eight in the illustrated)
Alternatively, they are directly fastened by substantially the same bolts.

Similar to the first and second embodiments, the shearing moment M _u rivets or bolts groups upper flange, lower flange
The ratio of the shear moment M _l rivets or bolts groups 12l, undercarriage frame 14 and packing box within a _{1.2 ≦ M l / M u ≦} 5
18 selected appropriately depending on the torsional rigidity of, by adapting to the shearing force S _u 'and S _l' acting on upper flange and lower flange, and the intensity of each rivet or bolt group as each appropriate Therefore, the durability of the cross member 12 and the side rails 10 can be improved. Further, the flange widths bu and bl of the upper flange and the lower flange of the cross member 12 are set to the shearing force S _u ′ and
By adjusting the dimension to S _l ′, the weight of the cross member can be reduced at the same time. Further, instead of the cross member shown in FIG. 7, as shown in FIG. 8, the plate material forming the upper flange 12u, the plate material forming the lower flange 12l, and the plate material forming the web 12w are joined by welding. The I-shaped cross-member 12 thus formed can be used, and in this case, substantially the same effect can be obtained.

Furthermore, when fixing both ends of the cross member 12 shown in FIGS. 7 and 8 to the side rails 10, they can be indirectly fastened using gussets as in the first embodiment.

(Advantages of the Invention) As described above, the chassis frame with a luggage box according to the present invention is provided with a pair of left and right side rails extending in the vehicle front-rear direction and having a groove-shaped cross section, and a cross-sectional shape arranged in the vehicle width direction. Is a groove-shaped or I-shaped cross member, and both ends of an upper flange and a lower flange of the cross member are fastened to the side rail directly or indirectly through gussets by a plurality of rivets or bolts, respectively. A rivet for fastening an upper flange of the cross member to a side rail, comprising a chassis frame and a luggage box mounted on the chassis frame and fastened to the side rail by a fixing means such as a U bolt. Or the number of bolts
n _u , the cross-sectional area of each rivet or bolt is A _ui , the distance from the equivalent center of gravity gu of the rivet or bolt group to the center line of each rivet or bolt is r _ui, and the lower flange of the cross member is the side rail. The number of rivets or bolts to be fastened is n _l , and the cross-sectional area of each rivet or bolt is
A _li , when the distance from the equivalent gravity center gl of the rivet or bolt group to the center line of each rivet or bolt is r _li , the rivet or bolt group of the upper flange and the lower flange, It is possible to effectively improve the durability and reliability of the joint portion between the side rail and the cross member in the chassis frame with a luggage box and to achieve weight reduction at the same time. Because it is possible, it is industrially beneficial.

[Brief description of drawings]

FIG. 1 is a plan view showing the first embodiment of the present invention (center plane O-
Left side of O) and bottom view (right side of center plane OO), FIG. 2 is a perspective view showing the cross member 12 in FIG. 1 extracted, and FIG. 3 is a line III-III of FIG. FIG. 4 is a partial sectional view taken along the arrow direction, FIG. 4 is a plan view (left side of the center plane OO) and a bottom view (right side of the center plane OO) showing the second embodiment of the present invention, and FIG. The drawing is a partial cross-sectional view taken along the line VV of FIG. 4 as seen in the direction of the arrow, and FIG. 6 is a plan view (left side of the center plane OO) and bottom view (showing the third embodiment of the present invention). Center plane OO
7), FIG. 7 is a sectional view of the cross member 12 in FIG. 6, FIG. 8 is a sectional view similar to FIG. 7 showing a modified example of the cross member 12 in FIG. 6, and FIG. 9 is a rivet or bolt. FIG. 10 is a diagram for explaining the equivalent center of gravity g of the group, FIG. 10 is a conceptual side view showing a mode of shearing force acting on the upper flange and the lower flange of the cross member when the chassis frame alone is twisted, and FIG. Is No. 10 when the chassis frame with packing box is twisted
It is a conceptual side view similar to a figure. 10 …… Side rail, 12 …… Cross member, 14 …… Car frame, 18 …… Packing box.

Claims (1)

[Claims] 1. A pair of left and right side rails extending in the front-rear direction of a vehicle body and having a groove-shaped cross section, and a cross member disposed in the vehicle width direction and having a groove-shaped or I-shaped cross-section. Both ends of the upper and lower flanges of the cross member are respectively fastened to the side rails directly or indirectly through gussets by a plurality of rivets or bolts, and U bolts mounted on the chassis frame. In which the luggage box is fastened to the side rails by the fixing means of No. 3, the number of the rivets or bolts for fastening the upper flange of the cross member to the side rails is n _u , and the cross-sectional area of each rivet or bolt is To
A _ui , the distance from the equivalent center of gravity gu of the rivet or bolt group to the center line of each rivet or bolt is r _ui, and the number of rivets or bolts for fastening the lower flange of the cross member to the side rail is n _l , The cross-sectional area of each rivet or bolt is A _li , and the distance from the equivalent center of gravity g _l of the rivet or bolt group to the center line of each rivet or bolt is r _li , the rivet or bolt of the upper flange and the lower flange is Flock Chassis frame with a packing box, which is arranged so as to satisfy