JP6735522B2 - Vehicle front structure - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle front structure that can understeer a vehicle.

A front suspension for suspending left and right front wheels and a front wheel steering device are provided at a front portion of an automobile. As an example of such a structure, the present applicant has previously proposed the structure described in Patent Document 1. ing.
In the structure described in the document, the front suspension includes a suspension member that is attached to a front side member and extends in the vehicle width direction, and a lower end of a knuckle to which a front wheel is attached is supported on each of both ends of the suspension member. The lower arms are connected to each other. A vehicle width direction intermediate region of the stabilizer is attached to an upper surface of the suspension member via a bracket provided with a rubber bush, and both vehicle width direction ends of the stabilizer are connected to struts via connecting rods. There is. On the other hand, in the front wheel steering system, a steering gear box is attached to an upper surface of a suspension member via a bracket having a rubber bush, and a knuckle arm is connected to each of both ends of the steering gear box. The tie rod is extended. A steering angle is given to the front wheels by displacing the tie rods in the vehicle width direction by the steering gear box.

However, in the above-mentioned structure, there is still room for improvement as described below.
That is, in designing/manufacturing an automobile, it is often the case that a general driver or the like wants to set the steering characteristic to understeer rather than oversteer or neutral in order to improve steering stability during vehicle turning. On the other hand, it is difficult to positively obtain the steering characteristic of the understeer with a structure in which the front suspension having the above-described conventional stabilizer and the front wheel steering device are simply combined. Therefore, there is room for improvement in this respect.

JP, 2007-131290, A

The present invention has been devised under the circumstances as described above, and provides a vehicle front structure capable of appropriately setting steering characteristics to understeer with a simple configuration. It is an issue.

In order to solve the above problems, the present invention takes the following technical means.

A vehicle front structure provided by the present invention is attached to a vehicle body member and extends in the vehicle width direction, and a lower arm that supports a knuckle on which a front wheel is mounted is connected to each of both ends in the vehicle width direction. Attached to the upper surface of the suspension member and a first rubber bush that enables relative displacement in the vertical direction, and extends in the vehicle width direction and both ends in the vehicle width direction. Each of the parts has a steering gear box in which a tie rod for connecting with the knuckle arm of the knuckle is extended, an intermediate region extending in the vehicle width direction, and both end parts connected to both ends of the intermediate region. In addition, the intermediate region is attached to the upper surface of the suspension member by using a second rubber bush that allows relative displacement in the vertical direction, while each of the both ends is provided with the front wheel. And a stabilizer connected to a member that moves up and down in accordance with the vehicle front structure, wherein regions near both ends of an intermediate region of the stabilizer are raised or lowered relative to the suspension member. At this time, the stabilizer and the steering gear are arranged so that regions of the steering gear box near both ends in the vehicle width direction are lowered or raised in a direction opposite to the regions near both ends of the stabilizer relative to the suspension member. When the vehicle is turning, the front wheel on the outer wheel side and the front wheel on the inner wheel side rebound and the front wheel on the inner wheel side rebounds when the vehicle turns, and the intermediate area of the stabilizer is further provided. The bounding-side end region of the steering gear box correspondingly rises relative to the suspension member, and the bounding-side end region of the steering gear box lowers due to the action of the structural portion. Side tie rod pulls the knuckle arm inward in the vehicle width direction, the front wheel on the outer wheel side is displaced to the toe-out side, while the end portion area on the rebound side of the intermediate area of the stabilizer, the steering gear The region near the end of the box on the rebound side and the tie rod on the rebound side are configured to be displaced to the toe-in side by causing an action opposite to that on the bound side, so that the front wheel on the inner wheel side is displaced . Is characterized by.

According to such a configuration, the scan tearing properties, can be understeer.
In the present invention, as a means for making the steering characteristic understeer, the stabilizer and the steering gear box are provided with a structure portion that associates these with the state in which the seesaw operation is possible so that they are displaced in the opposite directions. By such means, it is possible to appropriately suppress the complication of the entire structure, the increase in size, and the increase in weight, and to reduce the manufacturing cost.
In addition, since the stabilizer and the steering gear box are relatively moved up and down with respect to the suspension member against the elastic force of the first and second rubber bushes, the elasticity of these first and second rubber bushes is increased. By changing the ratio, it is possible to adjust so as to obtain a desired amount of understeer.

Other features and advantages of the present invention will become more apparent from the following description of the embodiments of the invention with reference to the accompanying drawings.

(A) is a partial cross-section main part plan view showing an example of the vehicle front part structure which concerns on this invention, (b) is an essential part enlarged view of (a). It is a partial cross section principal part rear view of the arrow II of FIG.1(b). FIG. 3 is a sectional view taken along line III-III in FIG. It is a schematic plan view which shows an example of the turning state of a vehicle.

Hereinafter, preferred embodiments of the present invention will be specifically described with reference to the drawings.

The vehicle front portion structure A shown in FIGS. 1 and 2 includes a structure portion B for attaching a steering gear box 1 and a stabilizer 2 shown in FIG. 3, which will be described later, to a suspension member 3. The basic configuration other than the related configuration is common to the conventionally known configuration described in Patent Document 1. Therefore, a part common to Patent Document 1 will be briefly described.

The vehicle front structure A includes a suspension member 3 that constitutes a front suspension FS that suspends a pair of left and right front wheels 9 (9a, 9b), a pair of left and right lower arms 30, and a stabilizer 2. Further, a steering gear box 1 constituting a front wheel steering device and a pair of left and right tie rods 4 are also provided.

The suspension member 3 has a hollow shape formed by joining, for example, an upper member and a lower member, extends in the vehicle width direction, and is attached to the pair of left and right front side members 80. The pair of front side members 80 correspond to an example of the vehicle body member according to the present invention, and are members that extend in the vehicle front-rear direction at both vehicle width direction outer side portions of the vehicle front portion. The pair of lower arms 30 are connected at their base end sides to both vehicle width direction ends of the suspension member 3 via front and rear rubber bushes 31 and 32, and are swingable in the vertical height direction. The lower portion of the knuckle 5 to which the front wheel 9 is attached via a hub 50 is connected to the tip end portion of each lower arm 30 via a ball joint 57. The knuckle 5 and the front wheel 9 can be horizontally rotated (changed in direction) about the ball joint 57.

The steering gear box 1 extends in the vehicle width direction, and two locations near both ends in the vehicle width direction are attached to the upper surface of the suspension member 3 by using the structure B of FIG. 3 described later. The tie rods 4 are members extending further outward in the vehicle width direction from both ends of the steering gear box 1 in the vehicle width direction. More specifically, one end of the tie rod 4 is connected to an end of a rack 10 (a part of which is shown in FIG. 3) located inside the steering gear box 1 via a ball joint 19. There is. The other end of the tie rod 4 is connected to the knuckle arm 5a at a position on the vehicle rear side of the wheel center C. The steering gear box 1 displaces the tie rod 4 in the vehicle width direction in response to a steering operation by a driver. Based on the displacement of the tie rod 4, the orientations of the knuckle 5 and the front wheel 9 change.

The stabilizer 2 has an intermediate region 20 that overlaps with the upper side of the suspension member 3 and extends in the vehicle width direction, and both end portions 21 that are connected to this intermediate region 20 and are bent toward the vehicle front side. It is connected to the strut 59 via the connecting rod 22 (see also FIG. 2). The lower part of the strut 59 is connected to the upper part of the knuckle 5. Two positions of the intermediate region 20 near the both ends in the vehicle width direction are attached to the upper surface of the suspension member 3 by utilizing the structure B of FIG. 3 described later.

The structural portion B of FIG. 3 is a structure in which the support portion 6A for the steering gear box 1 and the support portion 6B for the stabilizer 2 are fastened together with the suspension member 3 using bolts and nuts 87, 87a. More specifically, the support portion 6A for the steering gear box 1 includes a bracket portion (outer cylinder portion) 11 formed integrally with the steering gear box 1, and a through hole 12 penetrating the bracket portion 11 in the vertical height direction. It is provided with an inner cylinder portion 61 with a flange that is inserted therein and through which the bolt 87 is inserted, and a first rubber bush 60a that is interposed between the inner cylinder portion 61 and the bracket portion 11. On the other hand, the support portion 6B for the stabilizer 2 has a configuration in which the second rubber bush 60b into which the stabilizer 2 is inserted is held inside the bracket 62. The inner tubular portion 61 is sandwiched between the upper portion 62a and the lower portion 62b of the bracket 62. The bolt 87 is inserted through the upper portion 62a and the lower portion 62b of the bracket 62 and the inner side of the inner cylindrical portion 61, whereby the support portions 6A and 6B described above are fastened together.

The steering gear box 1 and the stabilizer 2 can be raised and lowered relative to the suspension member 3 within a range in which the first and second rubber bushes 60a and 60b can be deformed. In addition, in the structure B shown in FIG. 3, when the stabilizer 2 moves up or down while deforming the second rubber bush 60b, the steering gear box 1 deforms the first rubber bush 60a. A seesaw operation that descends or rises in the direction opposite to that of the stabilizer 2 occurs. This is because the bolt 87 is located between both the steering gear box 1 and the stabilizer 2, and this bolt 87 can serve as a fulcrum of seesaw operation, and whether the steering gear box 1 or the stabilizer 2 is raised or lowered while supporting the other. This is based on the fact that the supporting portions 6A and 6B are provided in a state of interfering with each other so as to affect the state.

Next, the operation of the vehicle front structure A will be described.

First, consider the case where the vehicle V makes a left turn as shown in FIG. In this case, since the right side of the vehicle body sinks due to centrifugal force, the right front wheel 9a (outer wheel) rises relative to the vehicle body, and the right side of the front suspension FS becomes the bound side. On the bound side, the stabilizer 2 rises relative to the suspension member 3 as shown by an arrow Na in FIG. Then, as shown by the arrow Nb in FIG. 2 and FIG. 3, the steering gear box 1 descends opposite to the suspension member 3 contrary to the above.

Here, as shown in FIG. 2, when the steering gear box 1 descends as shown by an arrow Nb, the ball joint 19 of the tie rod 4 also descends, so that the inclination angle α2 of the tie rod 4 in the vertical height direction increases. That is, when the front wheel 9a simply bounces, the tie rod 4 assumes an inclined posture with an inclination angle α1 as shown by an imaginary line L1 in FIG. 2, but when the ball joint 19 is lowered, The inclined posture shown by the imaginary line L2 with a larger inclination angle α2 becomes the position P2 in which the knuckle arm 5a is additionally pulled inward by an appropriate amount s1 inward in the vehicle width direction from the original position P1 (see FIG. 1( See also b)). As a result, the front portion of the front wheel 9a on the right side is turned to the right side on the outer side in the vehicle width direction by a proper angle from the original steering angle (toe-out side).

On the other hand, the left side of the front suspension FS is the rebound side unlike the above, but on this rebound side, the stabilizer 2 descends relative to the suspension member 3, and as a result, the steering gear box 1 faces the suspension member 3. And then rise. In this way, the rebound side performs an operation that is upside down from the above-mentioned bound side. As a result, according to the same principle as described above, the front portion of the left front wheel 9b is turned to the right side on the inner side in the vehicle width direction by a proper angle than the original steering angle (toe-in side).

For this reason, the steering characteristics of the vehicle V can be made understeer and the maneuverability can be improved. Since the main part of the vehicle front structure A is bilaterally symmetric, it is of course possible to obtain the same action when the vehicle V turns right as when turning left.

In the present embodiment, the steering gear box 1 and the stabilizer 2 are attached to the suspension member 3 via the structural portion B, and the attachment means are commonly used. Therefore, it is possible to improve productivity by reducing the structure, reduce the weight, and reduce the manufacturing cost. In addition, the strength of the understeer can be easily adjusted by changing the elastic moduli of the first and second rubber bushes 60a and 60b and the position of the structure B.

The present invention is not limited to the contents of the above-mentioned embodiment. The specific configuration of each part of the vehicle front structure according to the present invention can be modified in various ways within the scope intended by the present invention.

In the above-described embodiment, when the stabilizer 2 moves up or down, as a means for lowering or rising the steering gear box 1 in the opposite direction, a support portion 6A for the steering gear box 1 and a support for the stabilizer 2 are provided. Although the portion 6B and the portion 6B are fastened together by the bolt 87, the present invention is not limited to this. For example, it is possible to employ a means of bolting a bracket that supports the stabilizer to the bracket portion that supports the steering gear box. Further, in the present invention, in a state where the steering gear box 1 and the stabilizer 2 are separately attached to the upper surface of the suspension member 3, the steering gear box 1 and the stabilizer 2 are connected by an appropriate connecting member, and It is also possible to adopt a configuration in which the intermediate portion of the connecting member serves as a rotation fulcrum that functions as a fulcrum of the seesaw operation. With such a configuration as well, when the stabilizer 2 moves up or down, the steering gear box 1 can be moved down or up in the opposite direction, and the effect intended by the present invention can be obtained.
Both ends of the stabilizer may be attached to, for example, a lower arm instead of the strut, and the point is that it may be connected to a member that moves up and down with the front wheel.

A vehicle front structure B structure part (structure part relating the stabilizer and the steering gear box to the state in which the seesaw operation is possible)
1 Steering Gear Box 2 Stabilizer 3 Suspension Member 30 Lower Arm 4 Tie Rod 5 Knuckle 5a Knuckle Arm 6A Support (for Steering Gear Box)
6B support (for stabilizer)
60a, 60b First and second rubber bushes

Claims (1)

A suspension member that is attached to the vehicle body member and extends in the vehicle width direction, and a lower arm that supports a knuckle to which a front wheel is attached is connected to each of both ends in the vehicle width direction,
A first rubber bush that enables relative displacement in the vertical direction is attached to the upper surface of the suspension member, extends in the vehicle width direction, and is provided at both ends in the vehicle width direction. A steering gear box in which a tie rod that is connected to the knuckle arm of the knuckle is provided,
A second rubber having an intermediate region extending in the vehicle width direction and both end portions connected to both ends of the intermediate region, and the intermediate region being capable of relative displacement in the vertical direction on the upper surface portion of the suspension member. While being attached using a bush, each of the both ends is a stabilizer connected to a member that moves up and down with the front wheel,
A vehicle front structure comprising:
When the regions near both ends of the intermediate region of the stabilizer are raised or lowered relative to the suspension member, the regions near both ends of the steering gear box in the vehicle width direction of the stabilizer are opposed to the suspension member. A structure is further provided that associates the stabilizer and the steering gear box with a seesaw-operable state so that the stabilizer and the steering gear box are lowered or raised in a direction opposite to the both-ends-side region ,
When the front wheel on the outer wheel side bounces and the front wheel on the inner wheel side rebounds when the vehicle turns, the bounding side end area of the intermediate area of the stabilizer rises relative to the suspension member. Correspondingly, as a result of the bounding side end portion region of the steering gear box descending due to the action of the structural portion, the bounding side tie rod pulls the knuckle arm inward in the vehicle width direction, and the outer ring Side front wheel is displaced to the toe-out side,
The rebound side end region of the intermediate region of the stabilizer, the rebound side end region of the steering gear box, and the rebound side tie rod cause an operation opposite to that of the bound side, thereby causing the inner ring to move. The vehicle front structure is characterized in that the front wheel on the side is configured to be displaced to the toe-in side .

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