JPH0624353A - Cross member coupling structure for frame for automobile - Google Patents

Abstract

PURPOSE:To ensure the sufficient coupling strength of a cross member with a side rail by decreasing the increase of weight as much as possible. CONSTITUTION:A cross member 1 is coupled to the rear part of the spring support part 22 of a side rail 2, supported through the force of a leaf spring 5, through a gusset 3. A first reinforcing piece 32 is extended in the central direction of the car body of the cross member 1 to the spring support part 22 side of the weld part on the cross member 1 side of the gusset 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cross member connecting structure in a frame of an automobile. More specifically, the present invention relates to a cross member connecting structure in which a cross member is connected near a side rail to which a spring bracket is connected.

[0002]

2. Description of the Related Art Conventionally, a chassis frame of an automobile has a ladder-like frame by connecting both ends of a plurality of cross members arranged in the vehicle width direction between a pair of side rails extending in the vehicle front-rear direction. Is formed. FIG. 4 shows a structure for connecting the cross member to the side rails (see Japanese Utility Model Laid-Open No. 3-77785). Figure 4
In, Fr indicates the front of the vehicle, and Rh indicates the right-hand direction of the vehicle. This cross member coupling structure is one in which both ends of the cross member 1 are coupled to the side rails 2 via trapezoidal gussets 3 which are symmetrical with respect to the axis CL of the cross member 1 in the front and rear of the vehicle.

[0003]

By the way, leaf springs are arranged at the vehicle rear portion of the chassis frame, and both ends of the leaf springs are supported by side rails via spring brackets. A cross member arranged in the vehicle width direction is coupled to the side rail near the supporting portion. FIG. 3 shows a cross-member coupling structure in which the above-mentioned conventional technique is applied to this portion. In FIG. 3, Fr indicates the front of the vehicle, and Rh indicates the right-hand direction of the vehicle.

The upper and lower surfaces of the cross member 1 are welded to the side rails 2 via the gussets 3, and the side surfaces of the cross member 1 have flanges 11 formed by bending the ends of the cross member 1 on the side rails 2. It is joined by welding. The front end of the leaf spring 5 is directly supported by the spring bracket 4, and the rear end of the leaf spring 5 is shackle 15
It is pivotally supported by the spring bracket 4 via. The spring bracket 4 mounts the mounting portion 41 on the side rail 2
It is fixed to the spring support portion 22 of. An axle housing 6 is fixed to a middle portion of the leaf spring 5 by a U bolt seat 7 and a U bolt 7a, and an axle shaft penetrates the inside of the axle housing 6. A bound stopper 8 formed of an elastic member is provided on the lower surface of the side rail 2 above the axle housing 6 to regulate the amount of upward movement of the axle shaft.

FIG. 5 is a diagram showing moments in three axial directions with the vehicle height direction as the H axis, the length direction as the L axis, and the width direction as the W axis. The shaded rectangle near the origin is the end surface of the cross member 1 and is the shaded portion in FIG. The origin is the center of the end surface of the cross member 1.

When the vehicle runs on a rough road, an upward load F1 shown in FIG. 3 is applied to the axle housing 6 from the wheels, and the axle housing 6 moves upward. When the amount of movement is large, the upper surface of the axle housing 6 contacts the lower surface of the bound stopper 8, and a counterclockwise moment S1 acts upward on the side rail 2. As shown in FIG. 5, the moment S1 is largest at the bound stopper 8 and becomes smaller toward the left rear of the L axis.

Considering the case where the vehicle turns a curve or turns to the right, a rightward load F2 is applied to the axle housing 6 from the right wheel, and the axle housing 6
A moment S2 acts on the spring support portion 22 of the side rail 2 in the vehicle outer direction via the leaf spring 5 and the spring bracket 4. Moment S2
As shown in FIG. 5, is substantially constant up to the spring support portion 22, and becomes smaller toward the left of the L axis in FIG.

As described above, the moments S1 and S2 applied to the cross member 1 change in value before and after the vehicle with respect to the axis CL thereof, and the moment value is larger on the spring bracket 4 side. However, in the conventional structure, the gusset is formed symmetrically with respect to the axis line CL in the front and rear of the vehicle. Therefore, when trying to reduce the weight of the gusset, the coupling strength on the spring bracket side is insufficient, and conversely,
When trying to satisfy the strength of the spring bracket side, there is a problem that the coupling strength on the side opposite to the spring bracket side becomes excessive and the weight becomes heavy.

The moment S3 applied to the cross member 1 in the W-axis direction is small at the vehicle center line, and is outside the vehicle, that is, W in FIG.
It gets bigger toward the right side of the axis. Therefore, the apparent rigidity increases as the cross member 1 approaches the vehicle center.

In the cross member connecting structure of the automobile frame according to the present invention, the gusset connecting portion side having a large acting moment is transmitted to the portion having high rigidity to enhance the connecting strength and reduce the weight increase as much as possible. The purpose is to ensure good bond strength.

[0011]

[Means for Solving the Problems] To solve the above-mentioned problems, the cross member connecting structure for an automobile frame of the present invention employs the following means. That is, a pair of side rails are arranged in the vehicle front-rear direction, both ends of the leaf springs are supported by the respective support portions of the side rails, and the front and rear portions between the support portions of the side rails are arranged in the vehicle width direction. In a cross member connecting structure for an automobile frame in which both ends of a provided cross member are connected, the cross member is connected to the side rail via a gusset, and the gusset has one end connected to the side rail and the other. The end of the gusset is welded to the cross member, and the portion of the gusset to be welded to the cross member is formed by extending the weld end of the side rail on the support side toward the vehicle center rather than the opposite weld end. It is characterized by

[0012]

The welding end of the side rail of the gusset on the side of the supporting portion, which supports the leaf spring, is extended in the vehicle center direction from the welding end on the opposite side, so that the side rail of the cross member is joined to the supporting portion. The moment applied to the
Moment can be transmitted to the cross member of the cross member, which has apparently high rigidity, toward the center of the vehicle for reinforcement.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a perspective view showing a rear portion of a frame of an automobile, and FIG. 2 is a perspective view of coupling of the cross member of FIG. 1 to a side rail as seen obliquely from below.

1 is a cross member, 2 is a side rail, 3
Is a gusset, 4 is a spring bracket, and 5 is a leaf spring. The side rail 2 is formed in a box shape with a closed cross section and extends in the vehicle front-rear direction. And FIG.
The side rail 2 on the right side and the side rail 2 on the left side (not shown) are arranged in a pair. An obliquely extending step portion 21 is formed in the middle portion of the side rail 2 so that the clearance between the axle housing 6 and the side rail 2 at the time of bouncing can be secured.

The cross member 1 is, as shown in FIGS. 1 and 2,
It has a box shape with a closed cross section and extends in the vehicle width direction, and flanges 11 are formed on two side surfaces at both ends thereof. The side surface flanges 11 are welded to a pair of left and right side rails 2, respectively, and gussets 3 are welded to the upper and lower surfaces. By side rail 2
Is bound to. A plurality of cross members 1 are provided in the vehicle front-rear direction, and are also arranged at the rear portion of the spring support portion 22 of the side rail 2 as shown in FIG. Then, together with the side rails 2, a ladder-shaped chassis frame is formed.

As shown in FIG. 2, the gusset 3 is formed in a substantially trapezoidal shape with the bottom 31 as the bottom, and the two top points of the top bottom 34 are projected to form the first reinforcing piece 32 and the second reinforcing piece 33. ing. The first reinforcing piece 32 is formed longer than the second reinforcing piece 32, and when the gusset 3 is welded to the cross member 1 and the side rail 2, the first reinforcing piece 32 is located on the side of the spring supporting portion 22 of the side rail 2. Place it so that it comes to. In the gusset 3, the portion of the upper bottom 34 from the first reinforcing piece 32 to the second reinforcing piece 33 is welded to the cross member 1, and the portion of the lower bottom 31 is welded to the side rail 2 to form the cross member 1 and the side rail 2. Reinforces the joint.

The spring bracket 4 has a mounting portion 41 having a U-shaped cross section as shown in FIG. 1, and a cylindrical portion 4 is provided at the tip of a base portion 42 which is bent in a square shape from the side surface of the mounting portion 41.
3 is provided. As for the spring bracket 4, the mounting portion 41 is inserted into the spring supporting portion 22 of the side rail 2 from the side as shown in FIG.
It is bound by stopping at a.

The leaf spring 5 has leaf springs stacked in multiple stages and has mounting portions 51 at both ends.
A shaft 17 is rotatably supported at one end of a shackle 15 through a shaft 17. Further, the leaf spring 5 is supported by the side rail 2 by pivotally supporting the other end of the shackle 15 by the shaft 16 on the cylinder 43 of the spring bracket 4. An axle housing 6 which is disposed in the vehicle width direction at the center of the leaf spring 5 and has an axle shaft passed inside is fixed by a U-bolt seat 7 and a U-bolt 7a in a prismatic portion, and an upper side rail 2 thereof. A bound stopper 8 formed of an elastic member and protruding downward is attached to the lower surface. The bound stopper 8 limits the amount of upward movement of the axle housing 6.

The above-mentioned moments S1 and S2 are applied to the vehicle.
In the case where the cross member 1 is applied, although the value of the moment acting on the joint portion of the cross member 1 on the spring support portion 22 side is large, the first reinforcing piece 32 of the gusset 3 is changed to the second reinforcing piece 33
By forming the cross member 1 closer to the center of the vehicle and forming it longer, sufficient strength can be obtained at the joint portion of the cross member 1 on the spring support portion 22 side, the increase in the weight of the chassis frame itself can be minimized, and the cross member 1 and the side member can be prevented. Sufficient bonding strength of the rail 2 can be secured.

[0020]

As described above, in the cross member connecting structure for an automobile frame according to the present invention, the gusset welding end on the supporting portion side having a large acting moment extends from the welding end on the opposite side toward the vehicle center, By transmitting the moment to the portion having high rigidity, it is possible to enhance the coupling strength, minimize the increase in the weight of the chassis frame itself, and secure the sufficient coupling strength between the cross member and the side rail.

[Brief description of drawings]

FIG. 1 is a perspective view of a frame as seen from a side of a vehicle, showing a cross member coupling structure according to an embodiment of the present invention.

FIG. 2 is a perspective view showing a cross member coupling structure as seen from below the vehicle in one embodiment of the present invention.

FIG. 3 is a perspective view of a frame as seen from the side of the vehicle, showing a cross member coupling structure in the related art.

FIG. 4 is a perspective view showing a connecting portion of a cross member and a side rail in a conventional technique.

FIG. 5 shows moments S1, S2 applied to side rails,
It is a moment figure which shows S3.

[Explanation of symbols]

 1 ... Cross member 2 ... Side rail 3 ... Gusset 5 ... Leaf spring 22 ... Spring support part (support part) 32 ... First reinforcement piece (welding end) 33 ... Second reinforcement piece (weld end)

Claims (1)

[Claims] 1. A pair of side rails are disposed in a vehicle front-rear direction, both ends of a leaf spring are supported by respective support portions of the side rails, and vehicle widths are provided at front and rear positions between the support portions of the side rails. In a cross member coupling structure for an automobile frame, in which both ends of a cross member arranged in a direction are coupled, the cross member is coupled to the side rail through a gusset, and one end of the gusset is the side rail. The other end of the gusset is welded to the cross member by welding the other end of the gusset to the support member side of the side rail so as to extend in the vehicle center direction from the opposite weld end. A cross member coupling structure for an automobile frame, which is characterized by being formed as follows.