JPS6244851Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to improvement of an automobile chassis frame.

Conventionally, in many vehicles such as buses and trucks, the weight of the front and rear portions of the vehicle is supported by rigid axle suspensions. This rigid axle suspension has the advantage of a simple structure and easy maintenance, but the unsprung weight is large and the movement of both left and right wheels is coupled, which can impair ride comfort and handling stability. In order to eliminate these many inconveniences, it is desirable to use an independent suspension. However, it is difficult to attach an independent suspension to a ladder-type chassis frame that is often used in conventional buses.
For example, as shown in FIG.
In the case of a vehicle in which the chassis frame 3 is formed by a pair of long side rails 1 and a large number of cross members 2 that connect these side rails with a distance L maintained in the vehicle width direction B, the pair of side rails 1 are long. By ensuring a predetermined distance L between the rails 1, rigidity against lateral bending due to load is ensured. However, the length L2 of the suspension control arm 4 is restricted by this distance L and the vehicle width L1, making it impossible to obtain a sufficient length L2, and the degree of freedom in selecting the suspension geometry is small. . On the other hand, if the distance L between the pair of side rails 1 is reduced as shown in FIG. 2 in order to ensure a sufficient length L2 of the suspension control arm 4, the chassis frame 3 will be Reduces bending stiffness and torsional stiffness around the vehicle centerline. Moreover, the palm frame 3
In this case, a relatively long outrigger 5 for maintaining rigidity in the vehicle width direction B is attached to the side rail 1, which is disadvantageous in terms of strength.

The purpose of this invention is to provide an automobile chassis frame that can be fitted with an independent suspension that has a large degree of freedom in selecting suspension geometry.

The frame chassis of an automobile according to this invention is formed long in the longitudinal direction of the vehicle, and includes a pair of left and right side rails that are supported by an independent suspension system having a control arm extending in the width direction of the vehicle from the road surface due to the weight of the vehicle, A mounting portion of an independent suspension system is formed in each part of the straight portion of the pair of side rails, and the mounting portions of the independent suspension device are offset to the vicinity of the vehicle center line extending in the longitudinal direction of the vehicle, and the mounting portions are rigidly connected to each other,
A pair of auxiliary rails are provided that face the pair of straight parts at approximately the same interval and have both ends thereof fixed to the side rails, and the pair of auxiliary rails are arranged in the space formed by the deflection of the mounting part. The central part of the auxiliary rail is bent upward so as to straddle the section, and the central part of the auxiliary rail is formed as a vehicle body side attachment part that receives a load from the buffer member of the independent suspension system.

For this reason, only the mounting portion of the pair of side rails where the independent suspension system is attached is biased toward the vehicle center line, which allows a sufficient length of the control arm of the independent suspension system, providing a large degree of freedom in selecting the suspension geometry. In particular, since the auxiliary rail strengthens the rigidity around the mounting portion of the independent suspension system and receives the load from the buffer member, the degree of freedom in the vehicle body structure is expanded. In addition, the other parts of the pair of side rails, that is, the parts other than the mounting portions of the independent suspension system, can ensure sufficient spacing in the vehicle width direction, and can ensure bending rigidity in the lateral direction and torsional rigidity around the vehicle centerline.

This invention will be explained below with reference to the accompanying drawings.

FIG. 3 shows an automobile chassis frame (hereinafter simply referred to as a chassis frame) 6 as an embodiment of this invention. This chassis frame 6 forms the skeleton of a frame-structured vehicle that supports the vehicle weight of a bus (not shown) only by the chassis frame. This chassis frame 6 includes a pair of side rails 7 formed long in the vehicle longitudinal direction A, and a large number of cross members 8 that connect the pair of side rails 7 to each other in the vehicle width direction B so as to maintain an interval L3. It is fixed to the outer surface of each side rail 7 and is attached to the floor plate 9 of the vehicle.
(See FIG. 4). The pair of side rails 7 are made of steel with a substantially U-shaped cross section, and have a straight portion 11 that is substantially parallel to the vehicle center line and has a distance L3 from each other, and a mounting portion 13 for attaching the front suspension 12. It is formed by Both mounting portions 13 of the pair of side rails have an X-shape in plan view.
That is, the mounting portions 13 are biased toward the vehicle center line, overlap each other at the vehicle center line position, and are welded.
Further, a center member 14 serving as a lower rigidity reinforcing member having a closed cross section is welded to the lower surface of the mounting portion 13 in the longitudinal direction A of the vehicle. Furthermore, the side rail 7 has a mounting portion parallel to its mounting portion 13, that is,
A pair of auxiliary rails 15 facing the straight portion 11 at substantially the same distance are welded. The auxiliary rail 15 has both ends welded to the straight portion 11, and its central portion is bent upward, and the entire auxiliary rail 15 is located in the space created by the deflection of the mounting portion 13 toward the vehicle center line. It is formed to straddle the front suspension 12. In this way, the lateral bending rigidity of the mounting portion 13 and the torsional rigidity around the vehicle center line are determined by the center member 1 in addition to the pair of side rails 7.
4 and the auxiliary rail 15.

As shown in FIG.
6, a suspension support 17 that is pivotally connected to the suspension support 17, vertical control arms 18 and 19 that regulate the vertical movement of the suspension support 17, and a coil spring that elastically transmits the vehicle weight from the center of the auxiliary rail 15 to the upper control arm 18. 20. This vertical control arm 18,
In order to obtain a desired suspension geometry, the respective lengths L4 and L5 of the wheel 19 are set within the range of the vehicle width L6. The upper control arm 18 is pivotally connected to the upper part of the suspension support 17 and the mounting part 13 of the side rail, respectively, and the lower control arm 19 is connected to the lower part of the suspension support 17 and the arm connecting part 141 at the lower end of the center member 14, respectively. It is pivoted. Therefore, even if a large lateral force is applied from the wheel 16 side via the upper and lower control arms 18 and 19, the lateral force is absorbed through the pair of mounting parts 13 and the center member 14, which are stiffened by being rigidly connected to each other. It can be securely received on both side rails. Furthermore, since the upper and lower control arms 18 and 19 receive braking force and impact from the road surface from the wheel 16 side, they are bifurcated to ensure durability against these forces and also to ensure rigidity as a positioning link for the wheel 16. (See Figure 3). For this reason, each wheel 1
Part of the braking force and impact from the 6 side is provided by the coil spring 20.
The information is transmitted to the center of the auxiliary rail 15 through the bifurcated upper and lower control arms 18 and 19.
As a result, the signal is transmitted to two points a and b on the mounting portion 13 side and two points c and d on the arm connecting portion 171. In this way, the braking force and impact from the wheels 16, that is, the reaction force from the road surface due to the weight of the vehicle, is divided into a plurality of parts by the front suspension 12 and applied to the chassis frame 6. Therefore, the reaction force from the road surface, which is transmitted to the mounting part 13 as an axial force through the bifurcated shaft part of the upper control arm 18, is divided into smaller parts by the front suspension 12, and the two points on the side rail 7 are divided into smaller parts by the front suspension 12. As for the strength and rigidity at points a and b, the burden of reaction force is smaller than in the case of a rigid axle suspension, so the weight of the side rail can be reduced by that amount.

The chassis frame 6 shown in FIG. 3 has an X-shaped mounting portion 13 formed on a portion of a pair of side rails 7, followed by a straight portion 11 with a distance L3. This attachment portion 13 is sufficiently offset toward the vehicle center line side, and there is sufficient space between it and the vehicle width L6, so that the front suspension 12, which is an independent suspension, can be easily attached.
Furthermore, the vertical control arms 18 and 19 of the front suspension to be attached can have the desired lengths L4 and L5, thereby increasing the degree of freedom in selecting the suspension geometry. Furthermore, since the straight portion 11 maintains a sufficient distance L3, sufficient strength can be ensured at this portion.

In the chassis frame 6 shown in FIG. 3, the mounting portions 13 of the pair of side rails are sufficiently offset from the vehicle center line, and both mounting portions 13 in this area are directly welded, but as shown in FIG. , the deflection of the mounting portion 25 may be reduced and the interval L7 may be provided. The pair of side rails 23 of this chassis frame 22 are formed by a straight portion 24 that maintains a spacing L8, and a mounting portion 25 that maintains a spacing L7 smaller than this spacing L8.
Incidentally, since this chassis frame 22 includes the same members as the chassis frame 6 shown in FIG. 3, the same members are given the same numbers and their explanations will be omitted. The mounting portions 25 of the pair of side rails 23 are attached to plate-shaped brackets 21 that are long in the vehicle width direction B while maintaining the distance L7.
The upper surfaces thereof are connected, and the lower surfaces thereof are connected by a center member 26 having a closed cross section. Furthermore, an auxiliary rail 15 similar to that shown in FIG. 3 is welded to the side rail 23 in parallel with the mounting portion 25 thereof. Therefore, the side rail attachment portion 25 can ensure lateral bending rigidity at that position and torsional rigidity around the vehicle centerline by using the center member 26 and the auxiliary rail 15. Furthermore, since the distance L7 is also formed in the attachment portions 25 of the pair of side rails, the bending rigidity and the like are further strengthened compared to the chassis frame 6 shown in FIG. 3. As shown in FIG. 7, the front suspension 12 attached to the mounting part 25 further connects the control arm 18 to the upper part of the suspension support 17.
The lower control arm 19 is connected to the lower part of the suspension support 17 and the center member 2 by pivoting to the ends of the bracket 21 as the mounting part 25.
6, respectively. At this time, the length L9 of the bracket 21 in the vehicle width direction
is a shape that can be changed relatively easily, so when the chassis frame 22 is used for multipurpose purposes as a chassis frame for many types of automobiles, it is necessary to change the shape of this bracket to ensure the desired suspension geometry for each type of car. Length L9 can be easily adjusted,
convenient.

Similar to the chassis frame 6 shown in FIG. 3, the chassis frame 22 shown in FIG. You can make it bigger.

In FIG. 8, a pair of side rails 27 are attached to the mounting part 2.
The chassis frame 29 is shown divided into eight parts. This chassis frame 29 has side rails 27
The members of the straight portion 30 and the center member 30, which serves as the attachment portion 28 and has a closed cross section with a large vertical width, are integrally connected by welding. Since this chassis frame 29 includes the same members as the chassis frames 6 and 22 shown in FIGS. 3 and 5, the same members are given the same reference numerals and their explanations will be omitted. Since this center member 30 is made of a material with sufficient strength and rigidity, sufficient lateral bending rigidity and torsional rigidity around the vehicle centerline of the mounting portion 28 can be ensured, and the mounting portion 28 is located on the vehicle centerline side. Since it is sufficiently offset, the front suspension 12 can be easily installed, and the degree of freedom in selecting the suspension geometry can be increased. Moreover, the length of the side rail 27 in the longitudinal direction A of the vehicle is ensured by welding, which has the advantage that the length of each component of the side rail 27 can be short, making it easy to mold.

In the above description, the front suspension supports the weight of the vehicle using the coil springs 20, but in addition to this, air springs can also be used.

As mentioned above, by using a chassis frame to which this invention is applied, an independent suspension can be installed on a bus, truck, or special purpose vehicle. This increases the degree of freedom in selecting the suspension geometry.Furthermore, each mounting part is rigidly connected to each other to strengthen rigidity, so when lateral force from the wheel is received via the control arm. In addition, this lateral force can be reliably received by both side rails, and the auxiliary rail can strengthen the torsional rigidity around the mounting portion 13 and the lateral bending rigidity in the plane direction, thereby improving the running stability of the vehicle. In addition, the auxiliary rail can be used as a mounting portion on the vehicle body side for receiving the load from the buffer member (coil spring 20, etc.) while maintaining a sufficient degree of freedom in design.

[Brief explanation of the drawing]

1 and 2 are plan views of essential parts of different conventional chassis frames, and FIGS. 3, 5, and 8 are plan views of essential parts of different embodiments of this invention. Figure 4 is the X in Figure 3.
- An X-ray sectional view, FIG. 6 is a side view of the main part of the chassis frame shown in FIG. 5, FIG. 7 is a sectional view taken along the Y-Y line in FIG. 5, and FIG. It is a Z line sectional view. 6, 22, 29... Palm frame, 7, 2
3, 27... Side rail, 8... Cross member, 13, 25, 28... Mounting part, A... Vehicle longitudinal direction, B... Vehicle width direction,... Vehicle center line, 1
1, 24, 30... Straight portion, 15... Auxiliary rail, 20... Coil spring.

Claims (1)

[Scope of Claim for Utility Model Registration] 1. A pair of left and right sides that are long in the longitudinal direction of the vehicle and receive the reaction force from the road surface due to the weight of the vehicle via an independent suspension system having a control arm extending in the width direction of the vehicle. A mounting section for an independent suspension device that is offset to the vicinity of the vehicle center line extending in the longitudinal direction of the vehicle is formed in each part of the straight portion of the pair of side rails, and the mounting sections are rigidly connected to each other. In addition, a pair of auxiliary rails are provided that face the pair of straight parts at substantially the same distance and have both ends thereof fixed to the side rails, and the pair of auxiliary rails are formed by the deflection of the mounting part. 1. A chassis frame for an automobile, characterized in that the auxiliary rail is bent upward so as to straddle the space, and the central portion of the auxiliary rail is formed as a mounting portion on the vehicle body side that receives a load from a buffer member of the independent suspension system. 2. The independent suspension is of a double-width bone type, and a lower rigidity reinforcing member protruding downward from the attachment portions is fixed to each attachment portion of the pair of side rails, and the lower control arm of the independent suspension is The automobile chassis frame according to claim 1, which is supported by the mounting portion via the lower rigidity reinforcing member.