JPH075101B2 - Rear wheel suspension spring mounting device for trucks - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rear wheel suspension spring mounting device for a truck, especially for a rear two-axle truck.

(Prior Art) An example of a conventional rear wheel suspension spring mounting device for a rear two-axle truck will be described with reference to FIGS.
In the figure, reference numeral 10 generally indicates a chassis frame, which has a pair of left and right side rails 12 having a groove-shaped cross section and extending in the vehicle front-rear direction, and a cross member 14 extending in the vehicle width direction. It consists of A spring mounting member 16 (generally referred to as a trunnion base) for suspending a rear wheel is mounted on the lower side of the joint portion between the side rail 12 and the cross member 14 by a bolt or a rivet in a mode described in detail later, and the spring is mounted on the spring. A spring support base (20) is rotatably mounted on a trunnion (18) supported by a mounting member (16) and protruding outward in the vehicle width direction.

A central portion of a leaf spring mounting 22 formed by stacking a plurality of leaf springs on the spring support base 20 is supported by a fixing means such as a U bolt 24. A rear-front axle axle housing 26 is supported on the front end portion of the leaf spring device 22, and a rear-rear axle axle housing 28 is supported on the rear end portion. Further, the lower end portion of the spring mounting member 16 is mounted with a radius rod which is connected to the other end of a radius rod (not shown) pivotally attached to the rear front axle housing 26 and the rear rear axle housing 28, respectively. The part 16 'is integrally formed.

The spring mounting member 16 supports most of the sprung weight of the vehicle including the loaded cargo via the leaf spring device 22 and the radius rod, and at the time of starting, stopping, turning, etc., shear load, bending load, and torsion load, Furthermore, since it is operated under extremely harsh load conditions by receiving these combined loads, it is needless to say that sufficient strength and durability itself are required, but the spring mounting member 16 described above is used. Similarly, sufficient strength and durability are also required for the mounting member mounting portion of the chassis frame 10 that receives all the loads.

Therefore, as shown in detail in FIGS. 6 and 7, the groove-shaped members are back-to-back and the respective web portions are integrally joined by rivets or the like to form an assembly member having an I-shaped cross section. The following reinforcing structure is adopted in the connecting portion between the cross member 14 and the side rail 12.
That is, the inner end of the upper gusset 30u is fixed to the upper flange 14u of the cross member 14 by rivets or bolts 32, and the outer end of the gusset 30u is fixed by the rivets or bolts 34 arranged in a row. Is fixed to the upper flange 12u of the. Also cross member 14
The lower flange 14l of the lower gusset 30l having an L-shaped bent portion on the outer end thereof, the inner end of the lower gusset 30l, the reinforcing plate 36 disposed below the lower flange 12l of the side rail, and the intermediate between the two. The spacer 38 and the rivet 40 are
, And then the outer end of the lower gusset 30l, the lower side flange 12l of the side rail, and the reinforcing plate 36 are fastened together by a number of rivets or bolts 42 arranged in a row. An L-shaped bent portion of 30 l is fixed to the web 12w of the side rail 12 by a bolt or a rivet 44. Although not shown in FIG. 6, as clearly shown in FIG. 7, the upper end flange portion of the spring supporting member 16 is integrally fastened and fixed by the rivets or bolts 40 and 42. .

The reinforcing structure at the joint between the side rail 12 and the cross member 14 is such that the lower flange 12l of the side rail 12 that first receives the various loads transmitted from the spring mounting member 16 is connected to the reinforcing plate 36, the spacer 38 and the lower gusset 30l. The points that are reinforced by the side rails, the upper and lower gussets 30u and 30l that are reinforcement members, and the reinforcement plate 36 are all side rails.
It is characterized in that the upper and lower flanges 12u and 12l of the twelve are connected by a large number of bolts or rivets 34 and 42 arranged in a line.

(Problems to be Solved by the Invention) In the above-described conventional configuration, the load of the rear wheel coming into the chassis frame 10 from the trunnion 18 through the spring mounting member 16 is reduced by the row of bolts or rivets 42 to the lower flange of the side rail. It is transmitted from the reinforcing plate 36 fixed to the 12l to the cross member 14 through the flange 12l and the lower gusset 30l, and further from the cross member 14, fixed to the upper flange 12u of the side rail by a row of bolts or rivets 34. Upper gusset adapted to be transmitted to gusset 30u but secured to side rail flanges 12u and 12l by a row of bolts or rivets 34 and 42.
There is a problem in that the contribution of 30u and the reinforcing plate 36 to the bending rigidity of the side rails is low, and the vertical flanges 12u and 12l of the side rails that generate a larger stress than the web portion due to vertical bending and torsional deformation of the chassis frame 10 ,
Since a large number of holes for inserting the bolts or rivets 34 and 42 are drilled, there is a problem that the strength of the flanges 12u and 12l is significantly reduced. Furthermore, side rail 12
Most of the height of the web 12w is a single plate member that is not reinforced at all.
Since a space is formed between 14 webs 14w,
As shown in FIG. 8, by the upward force indicated by the arrow P, the web 12w of the side rail is deformed into an S shape and the lower flange 12l is bent at an acute angle with respect to the web 12w. It is easy to cause such deformation, and as a result,
There is a problem that stress is concentrated on the connecting portion between the web 12w of the side rail 12 and the lower flange 12l and the bent portion of the lower gusset 30l, and a crack as indicated by a symbol C in the drawing is likely to occur. As a result of these, there are disadvantages that the number of parts is large, the structure is complicated, the manufacturing cost is increased, and the weight is increased. I was worried about chipping and durability.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a rear wheel suspension spring mounting device for a truck, which has a simple structure, a small number of parts, is inexpensive, is lightweight, and has excellent durability by solving the above-mentioned drawbacks of the conventional structure. It is what

(Means for Solving the Problem) A rear wheel suspension spring mounting device according to the present invention is arranged between a pair of side rails extending in the vehicle front-rear direction and between the side rails, and extends in the vehicle width direction. An undercarriage frame having a cross member, a spring mounting member for supporting a spring for suspending rear wheels, a vertical side thereof fixed to the web of the side rail, and an upper end of the spring mounting portion below the lateral side thereof. An L-shaped bracket to which the flange portion is fixed, the lower flange of the cross member is fastened and fixed together with the lateral side of the bracket and the upper end flange of the spring mounting member, and the web of the cross member is the vertical side of the bracket. It is also characterized in that it is fastened and fixed together with the web of the side rail.

(Operation) According to the present invention, the spring mounting member that supports the rear wheel suspension spring is fixed to the lower side of the horizontal side of the L-shaped bracket, and the vertical side of the bracket is fixed to the web of the side rail. On the other hand, the web of the cross member is fastened and fixed together with the vertical side of the bracket to the web of the side rail. Therefore, the loads in the vertical direction, the vehicle width direction, and the vehicle body front-rear direction applied to the spring mounting member during traveling are reasonably transmitted to the web of the side rail in which the generated stress is smaller than that of the upper and lower flanges.

(Embodiment) An embodiment of the present invention will be specifically described below with reference to Figs. (Note that members that are substantially the same as or correspond to those of the conventional configuration described with reference to FIGS. 5 to 8 are denoted by the same reference numerals, and duplicate description will be omitted.) Side rail 12 of chassis frame 10 An inner stiffener 46 having a groove-shaped cross-section is inserted inside the inner side of the inner stiffener, and the outer surfaces of the upper and lower flanges 46u and 46l and the web 46w of the inner stiffener are respectively opposed to the upper and lower flanges 12u and 12l of the side rail 12 and the web. It is formed so as to be substantially in surface contact with the inner surface of 12w. Further, an L-shaped bracket 48 extending in the vehicle front-rear direction is inserted inside the inner stiffener 46, and a vertical side 50 of the bracket 48 is a web 46 of the inner stiffener 46.
Abutting on w, and by many bolts or rivets 52, side rail web 12w and inner stiffener web 46w
Is stuck to. The horizontal side 54 of the bracket 48 contacts the lower flange 46l of the inner stiffener 46 via the lower flange 14l of the cross member 14, and the horizontal side 54, the lower flange 14l of the cross member, the lower flange 46l of the inner stiffener, and the spring mounting. The upper end flange 56 of the member 16 is integrally fastened and fixed by a large number of bolts or rivets 58. Furthermore, the bracket 48 has its vertical side 50
The inclined reinforcing wall or the stay 60 that connects the horizontal side 54 with the horizontal side 54 is integrally formed by play or the like, or separately manufactured and fixed to the vertical side 50 and the horizontal side 54 by any means such as rivets.
The vertical side 50 and the horizontal side 54 are, as apparent from the figure, other adjacent members, that is, the side rails 12, the inner stiffener 46.
The cross member 14 is made of a thicker plate material and is reinforced by the inclined reinforcing wall or stay 60, and has a sufficiently higher rigidity than the adjacent members.

A vertical flange 62 is formed at the end of the web 14w of the cross member 14 by being bent into an L shape. The vertical flange 62 is formed by a plurality of bolts or rivets 64 and the vertical side 50 of the bracket and the inner stiffener. The web 46w and the side rail web 12w are fastened together. Further, the upper flange 14u of the cross member 14 is fixed to the upper flange 46u of the inner stiffener extending beyond the upper flange 12u of the side rail toward the vehicle body center line side by a bolt or a rivet 66.

According to this structure, the load of the rear wheel transmitted to the spring mounting member 16 through the trunnion 18 from the leaf spring device 22 for suspending the rear wheel during traveling of the truck is equal to the flange 56 at the upper end of the spring mounting member. Is transmitted to the lateral side 54 of the L-shaped bracket 48 having high rigidity through the lower flange 46l of the inner stiffener and the lower flange 14l of the cross member, which are fastened together to the vertical side 50 of the bracket 48 and the web of the cross member 14. It is transmitted to the web 12w of the side rail 12 via the vertical flange 62 formed at the end. That is, as shown in FIG. 3, by the rear wheel load acting on the lower flange 14l of the cross member 14, the web 12w is passed through the vertical flange 62 fixedly fastened to the web 12w by bolts or rivets 52. An action force f _h in the vehicle width direction and an action force f _{v in the} vertical direction (hence resultant force f _r ) are generated in the upper part of the web 12w, and at the same time, in the lower part of the same web 12w via the bolts or rivets 52, the lower part of the web 12w. Tensile force f in the vehicle width direction
_t is generated. As shown in FIG. 4, the rear wheel load acting on the horizontal side 54 of the bracket 48 causes the vertical side 50 to move.
Bolts or rivets 52 of the upper portion Kurumahaba direction of the applied force f _'h and vertical action force f' _v (hence force f _'r) are occurring in the same time the lower portion of the web 12w side rails via Kurumahaba direction tensile force f _'t is induced in the lower portion of the web 12w through. In this way, a substantial part of the rear wheel load is transmitted to the web 12w of the side rail 12 via the L-shaped bracket 48 and the cross member 14 without difficulty, so that the upper and lower flanges 12u and 12l of the side rail are excessively large. Stress does not occur. Also, the side rail 12
The inner stiffener web 46w, the vertical side 50 of the bracket 48 with high rigidity, and the vertical flange 62 of the cross member web are fastened together to the web 12w of the above, and are sufficiently reinforced so that even when overloaded, As shown in FIG. 8, no significant S-shaped deformation is caused, so that there is a problem that the stress is concentrated on the connecting portion between the web 12w and the lower flange 12l and the crack C is generated unlike the conventional case. Absent. Furthermore, since it is not necessary to form a large number of bolts or rivet insertion holes for fixing gussets or the like on the upper and lower flanges 12u and 12l of the side rail 12, the flange strength may decrease due to the large number of holes. Absent. As a result of these integrations, it is possible to realize a highly reliable configuration that has a small number of parts, a simple structure, is inexpensive, and is lightweight, and that can sufficiently withstand severe rough road driving in a significantly overloaded condition. it can.

Although the inner stiffener 46 is inserted inside the side rail 12 in the above-described embodiment, the inner stiffener can be omitted depending on the load condition of the vehicle. Further, in the above-mentioned embodiment, a normal I-shaped member is illustrated as the cross member 14, but a so-called back-to-back fixed web of two groove-shaped members as shown in FIG. 6 and FIG. A double channel type member or the like can be appropriately used. In the same embodiment, the vertical flange 62 at the web end of the cross member is formed integrally with the web 14w, but the L type member made separately is used. One vertical side may be fixed to the web 14w by rivets or the like, and the other side may be the vertical flange 62.

(Advantages of the Invention) As described above, the truck rear wheel suspension spring mounting device according to the present invention is arranged between a pair of side rails extending in the vehicle front-rear direction and the side rails and extending in the vehicle width direction. An undercarriage frame having existing cross members, a spring mounting member for supporting a spring for rear wheel suspension, and a vertical side thereof fixed to the web of the side rail and below the lateral side of the spring mounting member. An L-shaped bracket to which an upper end flange portion is fixed, the lower flange of the cross member is fastened and fixed together with the lateral side of the bracket and the upper end flange of the spring mounting member, and the web of the cross member is vertical to the bracket. It is characterized by being fastened together with the side rail together with the side rail web, and has a simple structure, a small number of parts, and excellent durability. The rear wheel suspension spring mounting device for the rack can be provided at low cost, which is industrially beneficial.

[Brief description of drawings]

FIG. 1 is a front view of an essential part showing an embodiment of the present invention, FIG. 2 is a side view as seen from the direction of arrow II in FIG. 1, and FIGS. 3 and 4 are a cross member 14 and an L-shaped bracket 48. FIG. 5 is a conceptual diagram showing a load transmission mode to the side rail web 12w, FIG. 5 is a schematic side view showing an example of a rear wheel suspension device in a conventional rear two-axle vehicle, and FIG. 6 is a spring mounting member in FIG. FIG. 7 is a perspective view showing the chassis frame structure of the mounting portion (however, the spring mounting member 30 is omitted), FIG. 7 is a front view seen from the direction of arrow VII in FIG. 6, and FIG. 8 is FIG. It is a front view showing the modification of the chassis frame shown. 10 …… chassis frame, 12 …… side rail, 14 …… cross member, 16 …… spring mounting member, 18 …… trunnion, 48 …… L-shaped bracket.

Claims (1)

[Claims] 1. A chassis frame including a pair of side rails extending in the front-rear direction of a vehicle body and a cross member arranged between the side rails and extending in the vehicle width direction, and a spring for suspending rear wheels. A spring mounting member and an L-shaped bracket whose vertical side is fixed to the web of the side rail and an upper end flange portion of the spring mounting member is fixed to the lower side of the horizontal side, and which is below the cross member. A flange is fastened and fastened together to a lateral side of the bracket and an upper end flange of a spring mounting member, and a web of the cross member is fastened and fastened together with a vertical side of the bracket to a web of the side rail. Rear wheel suspension spring mounting device