JPH02158461A - Chassis frame for vehicle - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a chassis frame for a vehicle such as a truck.

(Prior Art) A normal truck has a pair of left and right side rails each extending in the longitudinal direction of the vehicle and each having a groove-shaped cross section, and a plurality of side rails arranged in the vehicle width direction and having both ends fixed to the side rails. A front axle and a rear axle are attached to the chassis frame via suspension devices, respectively, and a cab, an engine, a cargo platform, etc. are mounted on the chassis frame.

The above-mentioned cross members include a member having a groove-shaped cross-section, a member having a type 1 cross-section, and a so-called alligator-shaped cross member having a figure-7-shaped expansion part at both ends connected to the side rail. It has been adopted.

(Problem to be Solved by the Invention) When a vehicle such as a truck is overloaded and travels at high speed on a rough road with severe unevenness, a large torsional load acts on the body frame, and the cross member is particularly affected. A large stress is generated near the joint with the side rail. A typical configuration of the side rail and cross member connecting portion in a conventional chassis frame will be explained with reference to FIG. 23.
The reference numeral 10 in the figure generally indicates a chassis frame, and the chassis frame includes a pair of left and right side rails 12 extending in the longitudinal direction of the vehicle and each having a groove-shaped cross section.

(In the figure, only the left side rail is shown.) A gusset 14 having a groove-shaped cross section is provided in the side rail 12.
The gusset 14 is a cross member having a groove-shaped cross section, and the width Y of the upper and lower flanges 16f in the longitudinal direction of the vehicle body (X direction in the figure). is substantially the same over the entire length in the vehicle width direction (X direction in the figure), and a PB test was conducted on the chassis frame 10 equipped with the cross member 16 described above, and the cross member flange 1
The stress generated at the free edge of 6f was investigated, and the 22nd
The results shown by the dotted line S1 in the figure were obtained. In FIG. 22, the vertical axis indicates the distance X from the plane of symmetry of generated stress, Xl indicates the intersection with the gusset 14, and x2 indicates the outer end of the cross member 16 in the vehicle width direction. As shown by the above curve S1, the stress generated at the edge of the flange 16f gradually increases as it moves outward in the width direction from the vehicle symmetry plane, and the stress generated at the edge of the flange 16f gradually increases as it moves outward in the width direction from the plane of vehicle symmetry.
It reaches the maximum value at confirmed.

An object of the present invention is to reduce the stress generated in the cross member of the undercarriage frame near the joint with the side rail, effectively avoid damage to the cross member, and improve the durability and reliability of the undercarriage frame. That is.

(Definition) In this specification, the term "equivalent center of gravity" with respect to a plurality of rivets that fix both ends of the cross member in the vehicle width direction to the side rail with or without a gusset is defined as follows. It is something.

That is, in FIG. 8, an arbitrary number (two or more) of rivets R1
, R2...Ri...Rn, respectively, are G1゜G2...Gi...Gn, and the cross-sectional area of each rivet is Ill HR2...ai...radius, respectively, and each rivet's cross-sectional area is The X coordinate and the X coordinate are respectively X1 t X2 River Xi"'
When Xn and y1gy2°")'i, the equivalent center of gravity G
X coordinate of , in which both ends of a cross member extending in the vehicle width direction are fastened by a plurality of rivets, wherein the cross member has a plurality of rivets arranged at a distance XB in the vehicle width direction from a plane of symmetry of the vehicle. When the width in the longitudinal direction of the vehicle body at the position PB near the equivalent center of gravity is designated as YB, and the width in the longitudinal direction of the vehicle body at the position PA located at a distance XA=XIl/2 in the vehicle width direction from the vehicle symmetry plane is yA7, ( YB/YA)2=1.5 to 2.5,
Further, the shape of the free edge between the PA and PR has a planar shape that expands linearly outward in the width direction of the vehicle.

(Function) According to the present invention, the planar shape of the cross member near the joint end with the side rail is changed to the above-mentioned special shape, that is, the width YB in the longitudinal direction of the vehicle body at the position XB near the equivalent center of gravity of the plurality of rivets; Y in the vehicle body longitudinal direction at the bisecting position XA between the plane of symmetry and the above position XB, and from the above position XA
The width of the vehicle body in the longitudinal direction at each intermediate position up to B is YA
By creating a shape that changes linearly from YB to YB, the maximum stress generated near the joint of the cross member with the side rail can be greatly reduced.

(Example) Examples of the present invention will be specifically described below with reference to the accompanying drawings. (Members or portions that are substantially the same as or correspond to those of the conventional configuration explained with reference to FIG. 23 are given the same reference numerals, and redundant explanation will be omitted.) First, FIG. In the first embodiment of the present invention shown in FIGS. 4 and 5, the cross member 16 has a vertical flange 16f formed by extending seven upper and lower flanges 16f outward in the vehicle width direction and bending them at right angles. ', and a vertical flange 16f' is fixed to the web 12w of the side rail 12 by a plurality of rivets 18. Since the plurality of rivets 18 are arranged on the web 12w of the side rail 12, the distance tG/2 between the equivalent center of gravity G and the plane of symmetry of the vehicle yO is
It is substantially equal to - of the entire length of the cross member 16 in the vehicle width direction, that is, in the X direction.

The planar shape of the cross member 16, that is, the seven upper and lower lunges 16
As shown in the figure, the width of the front and rear of the vehicle body is substantially equal from the vehicle symmetry plane yO to the intermediate position PA in the vehicle width direction.
YA, and the width in the longitudinal direction of the vehicle expands linearly from the same position PA to position PB near the outer edge in the vehicle width direction, forming YB.
It is formed so that More specifically, the position PB is set in the vicinity of the equivalent center of gravity G (including the center of gravity position G, of course) in the vehicle width direction, and the intermediate position PA has a distance XA from the vehicle symmetry plane yO that is equal to the vehicle symmetry of the position PR. face yO
It is set at equal distances from the point. And, between the widths YA and YB at the positions PA and PB, (YB
/YA) 2=2 is established.

The undercarriage frame 10 equipped with the cross member 16 having the above shape was subjected to a torsion test under the same conditions as the previous undercarriage frame shown in FIG.
When we measured the stress generated at the free edge of the flange 16f, we found that the maximum stress generated near the joint with the side rail 12 was sufficiently reduced, as shown by the solid line S2 in FIG. It has been confirmed that the vehicle is highly safe when driving on rough roads under such conditions, and that durability and reliability can be significantly improved. FIG. 5 also shows that when the cross member 16 is connected to the web 12w of the side rail 12 by the rivet 18, the web 16w of the cross member 16 is connected to the web 16w of the cross member 16 vertically.
This is a modification of the first embodiment in which a cross member flange 16W' is formed and the vertical flange 16W' is connected to the web 12w of the side rail.
can be reduced in substantially the same way as in the case of FIG.

In addition, tests were conducted by varying the width YA and YB of the cross member flange 16f in the longitudinal direction of the vehicle body, and it was found that the above (Yn/'A) = 2 was optimal;
It has been confirmed that when the value is 5 or more, the stress reduction effect reaches a plateau and there is a problem of unnecessarily increasing weight, while when the above value is 1.5 or less, the stress reduction effect is not sufficient and concerns about strength increase. Ta.

Next, FIGS. 2 and 6 show a second embodiment of the present invention,
In this embodiment, a cross member 16 having a groove-shaped cross section and having a planar shape similar to that of the first embodiment has seven flange 16 on its upper and lower sides.
f is fixed to the corresponding upper and lower flanges 12f of the side rail 12 by a plurality of rivets 18. The width YB of the seven flange 16f in the longitudinal direction of the vehicle body at a position PB that is substantially equidistant from the vehicle symmetry plane yO to the equivalent center of gravity G of the rivet group, and the distance XA from the vehicle symmetry plane yO = XB/
2 It is formed so that two things hold true.

Furthermore, FIGS. 3 and 7 show a third embodiment of the present invention,
In this embodiment, upper and lower flanges 16f of a cross member 16 having a groove-shaped cross-section and a planar shape similar to that of the first embodiment are fixed to corresponding flanges 14f of a gusset 14 having a groove-shaped cross-section by a plurality of rivets 18. The web 14w of the gusset 14 is fixed to the web 12w of the adjacent side rail by a rivet 20.

Width YB of the seven flange 16f in the longitudinal direction of the vehicle body at position XB, which is substantially equidistant from the plane of vehicle symmetry yo to the equivalent center of gravity G of the plurality of rivets 18, and the distance from the plane of vehicle symmetry yo, XA=XB/2. Between the width YA in the longitudinal direction of the vehicle body at the bisecting position, (YB/Y cut 2 = 1.5
The dimensions of each part are determined so that a relationship of ~2.5, preferably 2, is established.

When the stress generated at the free edge of the cross member flange 16f was examined by torsion tests for the second and third embodiments, results were obtained that approximated the curve S2 in FIG. 22, and the side It has been confirmed that the maximum stress generated in the seven flange 16f near the joint with the rail 12 can be reduced more effectively than in the past.

FIG. 9 shows a fourth embodiment of the present invention, in which a cross member 16 having an I-shaped cross section as shown in FIG. 12 is used.

The cross member 16 has seven vertical langes 16f', similar to those shown in FIG. ing.

The cross member 16 is located slightly on the vehicle symmetry plane yo side from the equivalent center of gravity G of the plurality of rivets 18, and is located slightly on the vehicle symmetry plane yo side.
Let YB be the width of the flange 16f in the longitudinal direction of the vehicle at a distance of XB from YB, and let YA be the width of the flange 16f in the longitudinal direction of the vehicle at a position PA that is distance XA-XB/2 from the plane of vehicle symmetry yO. When, YB
and YA (Ya/YA) 2= 1.5・~2,
5. Preferably, two relationships are established, where PA and PB
The flange 16f is formed to have a planar shape that expands linearly between the two.

As described above, the undercarriage frame includes the cross member 16 having a planar shape in which the vicinity of the joint with the side rail 12 expands linearly outward, and the normal width of the cross member 16 in the longitudinal direction of the vehicle body is substantially equal over the entire length. ■A torsion test was carried out under road-to-road conditions for the undercarriage frame equipped with a cross member with a shaped cross-section, and the stresses generated at the free edges of the upper and lower seven flange 16f of the cross member were compared. As in the case of , it was confirmed that the maximum stress was significantly reduced compared to that provided with the conventional cross member of the same type, and therefore durability and reliability could be effectively improved.

FIG. 10 shows a fifth embodiment of the present invention. In this embodiment, a cross member 16 having an I-shaped cross section and having a planar shape similar to that of the fourth embodiment has its upper and lower flanges 16f connected to the corresponding upper and lower sides of the side rail 12. Multiple rivets 1 on flange 12f
It is fixed by 8. A position PB that is substantially equidistant from the vehicle symmetry plane yo to the equivalent center of gravity G of the rivet group
(YB/
/Y□)2-1.5 to 2.5, preferably 2, is set so that the relationship holds true.

Furthermore, FIG. 11 shows a sixth embodiment of the present invention. In this embodiment, a cross member 16 having an I-shaped cross section and having a planar shape similar to that of the fifth embodiment has upper and lower flanges 16f having a groove-shaped cross section. The gusset 14 has a web 14w secured to a corresponding flange 14f of the side rail by a plurality of rivets 18, and a web 14w of the gusset 14 is secured to a web 12w of an adjacent side rail by a rivet 2o.

The width YB of the flange 16f in the longitudinal direction of the vehicle body at a position PR that is substantially equidistant from the plane of symmetry yo of the vehicle to the equivalent center of gravity G of the plurality of rivets 18 is the distance XA-XB/2 from the plane of symmetry yO of the vehicle. (YB/YA) 2=1 between the width YA in the longitudinal direction of the vehicle body at the trisection position PA
．． The dimensions of each part are determined so that a relationship of 5 to 2.5, preferably 2, is established.

A torsion test was conducted for each of the fifth and sixth embodiments, and the stress generated at the free edge of the cross member flange 16f was investigated. When compared with the stress generated at the free edge of the flange of a cross member with the same normal ■-shaped cross-section,
Results substantially similar to the curves S2 and Sl in FIG. 22 are obtained, and in the fifth and sixth embodiments, the maximum stress generated is significantly reduced, and therefore durability and reliability are effectively improved. It was recognized that Moreover, instead of the cross member 16 having a so-called integral type 1 cross-sectional shape as shown in FIG. 12, members 16a and 16b having a groove-shaped cross section as shown in FIG. 13 are used back to back. It has been confirmed that substantially the same effect can be obtained even in the assembly type cross member 16 which is physically connected with the rivets 22 to form a square cross section.

FIG. 14 shows a seventh embodiment of the present invention, and in this embodiment, as shown in FIG. 17, the upper member 16u has a hat-shaped cross-section for most of its length except for both ends, and is flat. A lower member 16t made of a plate with a large number of rivets 24
The upper member 16u and the lower member 1
Expand 6t into a 7-shape and attach to each tip 7 lunge 16
An alligator-shaped cross member 16 formed with u' and 16t' is used. The cross member 16 is fixed to the side rail 12 by fastening the mounting 7 flange 16u' and 16t' to the side rail web 12 w IK with a plurality of rivets 18. (Note that the lower member 161 of the cross member 16 is replaced by the upper member 16
The cross member 1 is made by using a member with a hat-shaped cross section as in u and integrally joining them with rivets 24 facing each other.
It may also form a 6. ) The cross member 16 has a width YB in the longitudinal direction of the vehicle body at a position PB that substantially coincides with the equivalent center of gravity G of the plurality of rivets 18 and is a distance XB from the vehicle symmetry plane yo, and When YA is the width in the longitudinal direction of the vehicle body at position PA, which is a distance of XA=XB/2,
Between YB and YA (YB/YA) = 1.5 to 2.5,
Preferably, two relationships are established, and the planar shape of the cross member expands linearly between PA and PB.
It is formed to have a letter shape.

Regarding the undercarriage frame equipped with the cross member 16 having the above-described planar shape and the undercarriage frame equipped with a normal alligator-type p/o cross member whose width in the longitudinal direction of the vehicle body is substantially equal over the entire length, the cross member 16 has a substantially concave shape. A torsion test was conducted under the conditions of − to examine the stress generated at the front and rear edges of the cross member. It has been confirmed that the maximum stress is significantly reduced and therefore durability and reliability are improved.

15 and 18 show an eighth embodiment of the present invention. In this embodiment, the ends in the vehicle width direction of the upper member 16u and lower member 16t of the alligator cross member 16 having the same planar shape as the seventh embodiment are provided with a plurality of rivets 18, respectively.
It is fastened to the upper and lower flanges 12f of the side rail 12 by.

The cross member 16 has a width YB in the longitudinal direction of the vehicle body at a position PB that is substantially equidistant from the vehicle symmetry plane yO to the equivalent center of gravity G of the rivet group, and a distance XA-XB/2 from the vehicle symmetry plane yO. When the width of the vehicle body in the longitudinal direction at the distant position PA is defined as YA, there is a gap between YB and YA (YB/YA)2=i, 5 to 2.5, preferably 2.
It is formed so that the following relationship is established.

Further, FIGS. 16 and 19 show a ninth embodiment of the present invention, in which the upper member 16u and lower member 161 of the alligator-shaped cross member 16 have the same planar shape as the seventh embodiment. The ends in the width direction are each fixed to seven corresponding flanges 14f of a gusset 14 having a groove-shaped cross-sectional shape by a plurality of rivets 18, and the gusset 14 connects its web 14w to the web 12 of the adjacent side rail.
w with rivets 20. The above black,
The width of the smenpa 16 in the vehicle body longitudinal direction at a position substantially equidistant XB from the vehicle symmetry plane yO to the equivalent center of gravity G of the plurality of rivets 18 is defined as YB, and the vehicle symmetry plane yO
When YA is the width in the longitudinal direction of the vehicle body at position PA, which is a distance XA=XB/2 from It is formed in such a way that a relationship is established.

Regarding the above-mentioned 8th and 9th embodiments, a torsion test was conducted to investigate the stress generated at the front and rear edges of the cross member. As in the 7th embodiment, the side rail
It is recognized that the maximum stress generated near the joint with No. 2 is significantly reduced compared to the conventional method. Furthermore, the alliedeta type cross member 1 shown in FIGS. 17 to 19
In each case, the upper member 16u and the lower member 16t extend over the entire length of the cross member, and a closed cross-section is formed in the middle part except for the 7-shaped parts at both ends in the vehicle width direction, and the torsion shape is relatively high. Although it is rigid, as shown in FIG. 20, the lower member 16t is fixed only to the end of the upper member 16u to form a figure-7 joint, and thus the middle part of the cross member. Substantially the same effect can be achieved even in the alidata type cross member 16, which is composed only of the upper member 16u with an open cross section and has relatively low torsional rigidity.

Next, in a tenth embodiment of the present invention shown in FIG. 21, two cross members 16 having a groove-shaped cross section similar to those in the first to third embodiments are arranged side by side with a gap C in the longitudinal direction of the vehicle body. The gap C is, for example, 30 mm to 80 mm. Each cross member 16 has seven upper and lower flanges 16f, and upper and lower flanges 14f of a common gusset 14 having a groove-shaped cross section.
The gusset 14 connects its web 14w to the web 12w of the side rail.
It is fixed to by a large number of rivets 20.

Also in this embodiment, by configuring each cross member 16 in the same manner as in the third embodiment shown in FIG. 3, it is possible to reduce the maximum stress generated at the free end edge of each cross member flange 16f. This effectively prevents damage to the cross member and improves durability and reliability. In addition, the above two cross members 16 installed in parallel
are fastened to the web 12w of the side rail 12 with a plurality of rivets 18, similar to the first embodiment shown in FIG. Even when the cross members 16 are fixed to the upper and lower seven orthogonals 12f with a plurality of rivets 18, the same effect as in the first embodiment can be obtained by forming the planar shape of each cross member 16 to be substantially the same as in FIGS. 1 and 2, respectively. Obtainable.

In all of the embodiments described above, even if the cross member 16 is bent in the vertical direction to avoid interference with the differential, propeller shaft, etc., the effects and advantages of the present invention described above remain substantially unchanged.

(Effects of the Invention) As described above, in the vehicle chassis frame according to the present invention, the side rails extending in the longitudinal direction of the vehicle body are provided with a plurality of rivets at both ends of the cross member extending in the vehicle width direction. In the cross member, the width in the longitudinal direction of the vehicle body at a position PB near the equivalent center of gravity of the plurality of rivets, which is a distance XB from the vehicle symmetry plane in the vehicle width direction, is defined as YB, and the width in the vehicle body longitudinal direction is YB. Distance XA from surface to width direction
When the width of the vehicle body in the longitudinal direction at position PA, which is distanced from =XB/2, is y, -mo-, (YE/YA) 2= i
, s~2.5, and the shape of the free edge between the PA and PB has a planar shape that expands linearly outward in the width direction of the vehicle, This can effectively reduce the stress generated in the cross member during high-speed driving on rough roads under overload conditions and prevent damage to the cross member, thereby increasing the durability and reliability of the cross member and ultimately the undercarriage frame. It has the advantage of improving

[Brief explanation of the drawing]

FIG. 1 is a plan view showing a first embodiment of the invention, FIG. 2 is a plan view showing a second embodiment of the invention, and FIG. 3 is a plan view showing a third embodiment of the invention.
4 is a sectional view taken along line IV-IV in FIG. 1 in the direction of the arrow; FIG. 5 is a similar sectional view showing a modification of FIG. 4; FIG. 6 is a plan view showing the embodiment; is a cross-sectional view taken along the line ■-■ in Fig. 2 in the direction of the arrow, Fig. 7 is a cross-sectional view taken along the line ■-■ in Fig. 3 in the direction of the arrow, and Fig. 8 is the equivalent of multiple rivets. A diagram explaining the center of gravity, FIG. 9 is a plan view showing the fourth embodiment of the present invention, FIG. 10 is a plan view showing the fifth embodiment of the present invention, and FIG. 11 is a plan view showing the sixth embodiment of the present invention. 1st plan view showing
2 is a sectional view of a cross member in the fourth to sixth embodiments, FIG. 13 is a similar sectional view showing a modification of the cross member shown in FIG. 12, and FIG. 14 is a sectional view of a seventh embodiment of the present invention. A plan view showing an example; FIG. 15 is a plan view showing an eighth embodiment of the present invention; FIG. 16 is a plan view showing a ninth embodiment of the present invention;
17 is a sectional view taken along the xvn-shoulder line in FIG. 14 in the direction of the arrow, FIG. 18 is a sectional view taken along the 1-1 line in FIG. IXX-D (
FIG. 20 is a sectional view taken along the X-ray in the direction of the arrow, showing the alligator-shaped cross member 16 in FIGS. 17 to 19.
FIG. 21 is a partial side view showing a modification of the first embodiment of the present invention.
FIG. 22 is a diagram showing the manner in which stress is generated in the cross member 16 in the first embodiment in comparison with the conventional device shown in FIG. 23, and FIG. 23 is a diagram showing the conventional chassis. FIG. 2 is a partial plan view showing a typical configuration of a frame. 10... Chassis frame, 12... Side rail, 1
6...Cross member 18...Rivet, G...
Equivalent center of gravity of 18 groups of rivets.

Claims (1)

[Claims] In a vehicle in which both ends of a cross member extending in the vehicle width direction are fastened to side rails extending in the direction of the vehicle body using a plurality of rivets, the cross member has a distance in the vehicle width direction from the plane of symmetry of the vehicle. Let Y_B be the width in the longitudinal direction of the vehicle body at position P_B near the equivalent center of gravity of the plurality of rivets separated by X_B. When the width in the direction is Y_A, (Y_B/Y_A
)^2=1.5 to 2.5, and the above P_A and P
A vehicle chassis frame characterized in that the shape of the free edge between it and _B has a planar shape that expands linearly outward in the width direction of the vehicle.