JP3138265B2 - Suspension for vehicle steering wheel - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an improvement in a suspension for a steering wheel used for a vehicle such as an automobile.

2. Description of the Related Art Conventionally, as a suspension for a steered wheel of a vehicle, for example, a suspension shown in Japanese Patent Application Laid-Open No. 61-218408 is known.

In this conventional example, an upper link and a lower link for supporting a knuckle for rotating and supporting a wheel on a vehicle body are respectively constituted by a pair of front and rear arms, and a virtual kingpin is defined by an instantaneous center point of each link when viewed from above the vehicle body. It has become. Then, the virtual kingpin axis is displaced by the movement of the instantaneous center point generated at each link at the time of wheel steering, so that the caster angle at the time of wheel steering can be controlled.

(Problems to be Solved by the Invention) However, in the above conventional example, the instantaneous center point (intersection point of the extension line of each arm as viewed from above the vehicle body) defining the virtual kingpin axis is set outward in the vehicle width direction of the knuckle. Therefore, the knuckle is greatly displaced together with the displacement of the virtual kingpin axis (displacement of the intersection) generated during wheel steering. For this reason, in the above-mentioned conventional example, the wheel house of the vehicle body must be set to be considerably larger than that of a general vehicle in which the virtual kingpin axis is fixedly set. There was a problem that the in-vehicle performance deteriorated.

(Means for Solving the Problems) The present invention has been devised to solve the above problems, and includes an upper link constituted by a pair of front and rear arms between a knuckle for rotatably supporting wheels and a vehicle body. In a suspension for a steering wheel of a vehicle provided with a system and a lower link system, each arm of the two link systems has an inner end pivotally connected to the vehicle body side and an outer end pivotally connected to the knuckle, and The link system includes a front upper arm that extends forward toward the vehicle from the knuckle at the straight traveling position of the wheel and extends toward the vehicle body, and a rear upper arm that is disposed in the vehicle width direction when viewed from above the vehicle body at the straight traveling position. And the distance between the outer ends of the front and rear upper arms is set to be smaller than the distance between the inner ends. A front lower arm that is disposed in the vehicle width direction when viewed, and a rear lower arm that is inclined toward the vehicle rear side from the knuckle and extends toward the vehicle body at the straight-ahead position, and between the outer ends of the front and rear lower arms. The distance is set smaller than the distance between the inner ends, and the outer end of the front upper arm is on the extension of the rear upper arm at the straight-ahead position, and
The rear end of the rear lower arm is located outward of the outer end of the rear upper arm in the vehicle width direction, and the rear end of the rear lower arm is located outside of the front end of the front lower arm in the vehicle width direction at the straight-ahead position. And the casters on the turning inner wheel side are increased during steering.

(Operation) According to the present invention, the upper link system includes a front upper arm that inclines toward the vehicle front side from the knuckle and extends toward the vehicle body at the straight traveling position of the wheel, and a vehicle width direction when viewed from above the vehicle body at the straight traveling position. And a distance between outer ends of the front and rear upper arms is set to be smaller than a distance between inner ends, and the lower link system includes:
A front lower arm that is arranged in the vehicle width direction when viewed from above the vehicle body at the straight-ahead position, and a rear lower arm that is inclined toward the vehicle rear side from the knuckle and extends toward the vehicle body at the straight-ahead position; Since the distance between the outer ends of the lower arms is set to be smaller than the distance between the inner ends, the intersection (instantaneous center) of each extension of the front and rear upper arms and the intersection of each extension of the front and rear lower arms ( The instantaneous center) defines a virtual kingpin axis. When the wheel is steered, the instantaneous center point is displaced back and forth, so that the caster angle at the time of steering can be controlled in the same manner as in the conventional example.

In the present invention, in particular, in the straight traveling position of the wheel, the outer end of the front upper arm is located on an extension of the rear upper arm and is located outside the outer end of the rear upper arm in the vehicle width direction. Since the outer end of the lower arm is located outside of the outer end of the front lower arm in the vehicle width direction and on the rear side of the vehicle, the caster on the turning inner wheel side increases during steering.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a perspective view of a steering wheel suspension according to the present invention. As shown in FIG. 1, a wheel 1 is rotatably supported by a knuckle 2. The knuckle 2 is formed with a knuckle arm 3 protruding rearward. An outer end of a tie rod 4 is pivotally connected to a rear end of the knuckle arm 3 via a ball joint H. The parts are connected to each other via a joint T. Therefore, the steering output of the steering gear box 5 is input to the knuckle 2 via the tie rod 4.

Between the lower part of the knuckle 2 and the vehicle body, a lateral arm 6 as a front lower arm arranged substantially in the vehicle width direction;
A lower link system comprising a compression arm 7 as a rear upper arm which is located rearward of the lateral arm 6 and extends rearward and inward from the knuckle 2 side is provided. The outer end of the compression arm 7 is pivotally connected to the bottom of the knuckle 2 via a ball joint GN,
The inner end of the compression arm 7 is a rubber bush G
It is pivotally attached to the vehicle body side via. On the other hand, the outer end of the lateral arm 6 is pivotally connected to the knuckle 2 via a ball joint AN, and the ball joint AN is a ball joint.
It is arranged ahead of and above GN. The inner end of the lateral arm 6 is pivotally connected to the vehicle body via a rubber bush A, and the spring constant of the rubber bush A is set to be larger than that of the rubber bush G.

The knuckle 2 is integrally formed with an extension arm 8 that extends to bend above the wheel 1. And, between the upper end of the extension arm 8 and the vehicle body, a lateral arm 9 as a rear upper arm arranged in the vehicle width direction, and located in front of the lateral arm 9 and forward and inward from the knuckle 2 side. Tension arm as extended front upper arm
10 and an upper link system composed of the upper link system and the upper link system.
The outer end of the lateral arm 9 is pivotally connected to the upper end of the extension arm 8 of the knuckle 2 via a ball joint RN, and the inner end of the lateral arm 9 is pivotally connected to the vehicle body via a rubber bush R. On the other hand, the outer end of the tension arm 10 is pivotally connected to the upper end of the extension arm 8 of the knuckle 2 via a ball joint QN, and this ball joint QN is arranged outside the ball joint RN in the vehicle width direction. I have. The inner end of the tension arm 10 is pivotally connected to the vehicle body via a rubber bush Q. The spring constant of the rubber bush Q is set smaller than the spring constant of the rubber bush R.

In FIG. 1, reference numeral 11 denotes a drive shaft for transmitting the driving force input from the engine to the wheels 1, and reference numeral 12 denotes a spring damper unit connected to the vehicle body and the lateral arm 6 of the lower arm system. The lower end of the spring damper unit 12 is connected to the drive shaft 11
In order to avoid buffering, the arm is formed in a forked shape and connected to the lateral arm 6.

FIG. 2 schematically shows a plan view of FIG.
As shown in FIG. 2, in the lower link system, the ball joint GN is located outside and behind the ball joint AN in the vehicle width direction when viewed from above the vehicle body, and a line segment connecting the ball joints GN and AN is provided. Are set forward and inward with respect to the traveling direction. Also,
In the lower link system, the intersection point (instantaneous center point) KL of the extension line between the lateral arm 6 and the compression arm 7, which is the instantaneous rotation center of the link system and defines the virtual kingpin axis, is located slightly behind the center WO of the wheel 1. It has become something.

On the other hand, in the upper link system, the tension arm
The ball joint QN provided at the outer end of the ball joint RN is located on an extension of the axis of the lateral arm 9 when viewed from above the vehicle body and is located outside the ball joint RN in the vehicle width direction. And the line connecting QN is set in the vehicle width direction. For this reason, in the upper link system, the intersection (instantaneous center point) KU of the extension line between the lateral arm 9 and the tension arm 10, which is the instantaneous rotation center of the link system and defines the virtual kingpin axis, is provided.
Corresponds to the center of the ball joint QN in the straight traveling state of the wheel.

FIG. 3 schematically shows a rear view of FIG.
As shown in FIG. 3, the virtual kingpin axis KP defined by the aforementioned instantaneous center points KU and KL is set substantially upright and slightly inclining, and as shown in FIG. WO
Is set slightly positive, and the kingpin offset on the ground contact surface of the wheel 1 is set slightly negative. As is clear from the relationship in FIG. 2, the virtual kingpin axis KP is set to be inclined backward, and the caster trail on the ground contact surface is set to the plus side as shown in FIG. It has become something.

 Subsequently, the operation of the present embodiment will be described.

First, the basic operation of the suspension will be described. The lower link system is constituted by the lateral arm 6 and the compression arm 7, and the upper link system is constituted by the lateral arm 8 and the tension arm 10. The front-rear force is supported by the compression arm 7 and the tension arm 10,
The lateral force acting on the wheel 1 is supported by the lateral arms 6, 9, and the force applied to the wheel 1 can be efficiently distributed and supported by each arm. In the lower link system, the spring constant of the rubber bush A is set to be larger than the spring constant of the rubber bush G, and in the upper link system, the spring constant of the rubber bush R is set to be larger than the spring constant of the rubber bush Q. From
The camber rigidity against lateral force is high and stable steering stability is ensured, and the rigidity against longitudinal force is set relatively low, so that the ride comfort when riding on the protrusion is improved.

In addition, when the wheel 1 is running straight, the virtual kingpin axis KP
Is set substantially upright, and since the kingpin offset at the contact surface of the wheel 1 and the center WO is extremely small, the braking force acting on the contact surface of the wheel 1 and the wheel 1
The moment force acting around the virtual kingpin axis KP is reduced by the driving force and the engine braking force acting on the center WO of the vehicle, and the change in the steering force or the steering holding force with respect to the change in the driving and braking force can be suppressed.

Further, since the upper link system and the lower link system are each configured by two arms and the virtual kingpin axis KP is set, the arm outer end position and the kingpin angle can be individually set. And the upper link system is installed above the wheel 1,
The actual length of the upper link system in the vehicle width direction (here, the length of the lateral arm 9 in the vehicle width direction) can be set relatively long, and the camber change and tread change with respect to the vertical stroke of the wheel are reduced.

Next, the operation when the wheel is steered will be described with reference to FIGS. 4 and 5. When the wheel 1 becomes the turning outer wheel (in the illustrated case, the wheel 1 is steered to the right), the lower link system and The upper link system is in the state shown by the dashed line in FIGS. That is, in the lower link system, as shown in FIG. 4, the line segment (the lower part of the knuckle 2) connecting the ball joints AN and GN is displaced rearward and outward of the vehicle, and the instantaneous center point (the virtual kingpin axis) is defined. The intersection of the extension lines of the arms 6 and 7 as viewed from above the vehicle body) is the KLo displaced backward and inward from the KL point when traveling straight. On the other hand, in the upper link system, as shown in FIG. 5, the line connecting the ball joints RN and QN (the upper end of the knuckle 2) is displaced inward and rearward of the vehicle, and the momentary center point defining the virtual kingpin axis (The intersection of the extension lines of both arms 9, 10 as viewed from above the vehicle body) is KUo displaced backward and inward from the KU point when traveling straight
Becomes

When the wheel 1 is a turning inner wheel (in the illustrated case, the wheel 1 is steered to the left), the lower link system and the upper link system are in the states shown by broken lines in FIGS. That is, in the lower link system, as shown in FIG. 4, the line connecting the ball joints AN and GN (the lower part of the knuckle 2) is displaced inward and forward of the vehicle, and the instantaneous center point defining the virtual kingpin axis is KLi is displaced forward and inward from the KL point when traveling straight. On the other hand, in the upper link system, as shown in FIG. 5, the line connecting the ball joints RN and QN (the upper end of the knuckle 2) is displaced forward and inward of the vehicle, and the instantaneous center point defining the virtual kingpin axis is formed. Is KUi displaced forward and inward from the KU point when traveling straight.

As described above, in the turning outer wheel, since the lower portion of the knuckle 2 is displaced outward and the upper end of the knuckle 2 is displaced inward, the camber angle of the wheel rotatably supported by the knuckle 2 changes in the negative direction. As shown in Figs. 4 and 5, the inner displacement of the lower part of the knuckle 2 is much larger than that of the upper end of the knuckle 2, so that the camber angle of the wheel changes in the positive direction. Will do. As a result, a preferable steering camber change is obtained, and the grounding properties of the turning outer wheel and the inner wheel are improved, so that the cornering power that can be exhibited by the tire is increased, and the turning performance of the vehicle is improved.

This operation is constituted by a lateral arm 6 in which the lower link system is arranged substantially in the vehicle width direction and a compression arm 7 which is arranged inward and rearward in the vehicle width direction. It is possible to efficiently obtain the configuration by including the arranged lateral arm 9 and the tension arm 10 arranged inward and forward in the vehicle width direction.

Here, in particular, the operation of the upper link system will be described in more detail. The fact that the displacement of the line segment (upper end of the knuckle 2) connecting the ball joints RN and QN is small both when the outer ring is turned and when the inner ring is turned is fifth. It is clear from the figure. That is, in the upper link system, the displacement of the ball joint QN during steering of the wheel is extremely slightly suppressed because the ball joint QN is located on the extension of the lateral arm 9 when the wheel 1 is in the straight traveling state. As described above, the instantaneous center point KU that defines the virtual kingpin axis can be displaced relatively large while suppressing the displacement of the upper end of. And, suppressing the displacement of the upper end of the knuckle 2 to a small value means that the displacement of the wheel 1 can be suppressed to a small value, whereby the expansion of the wheel house of the vehicle can be suppressed.

As for the change of the caster angle, which is the inclination angle in the front-rear direction of the virtual kingpin axis, as shown in FIG. 6, the line connecting the instantaneous center points of the upper link system and the lower link system is viewed from above the vehicle body. The length of the front-rear component is almost the same on the turning outer wheel side as when traveling straight, and is larger on the turning inner wheel side than when traveling straight, so the caster angle on the turning outer wheel side hardly changes, but the caster angle on the turning inner wheel side increases. Will do. For this reason, as the steering angle increases, the caster angle and caster trail on the turning inner wheel side increase to secure the steering wheel return force (self-aligning torque), while the caster angle when traveling straight is small, and therefore, the steering response at the beginning of steering is small. The force can be reduced to improve the maneuverability of the vehicle. Here, as a method of increasing the caster angle during steering to secure the steering wheel return force, it is conceivable to increase the caster angle on the turning outer wheel side. In this case, however, the displacement of the instantaneous center point (KL) of the lower link system is considered. It is necessary to increase the displacement of the instantaneous center point (KU) of the upper link system by keeping it small, and to suppress the displacement of the instantaneous center point (KL) of the lower link system by using ball joints AN and GN
The distance between them must be set small, and in practice it is difficult to shorten this distance due to the size of the ball joint, and such a method cannot provide a sufficient effect. For this reason, in this embodiment, the displacement of the instantaneous center point (KL) of the lower link system is made relatively large, and the steering wheel return force is secured on the turning inner wheel side, so that the distance between the ball joints AN and GN is given a margin. The design flexibility has been increased.

In addition, since the steering wheel returning force is secured on the inner ring side as described above, there is no need to increase the displacement of the instantaneous center point (KU) of the upper link system. Since the length can be set relatively long,
From this point, the camber change and tread change with respect to the vertical stroke of the wheel can be reduced. That is, to increase the displacement of the instantaneous center point (KU) of the upper link system, the distance between the ball joints RN and QN must be set large, and the length of the upper link system in the vehicle width direction is inevitably shortened. Although the camber change with respect to the vertical stroke becomes large, the handle return force is secured on the inner wheel side in the present embodiment, so there is no such restriction on the setting, and the setting of the upper link system for suppressing the camber change is not required. It is possible.

According to the above embodiment, the following effects can be obtained.

First, since the arms for supporting the longitudinal force and the lateral force applied to the wheel 1 are separately set in the upper link system and the lower link system, the force applied to the wheel 1 can be efficiently dispersed and supported by each arm. It is easy to set the elasticity of the bush provided at the inner end of each arm, and the bush receiving the lateral force is hard and the bush receiving the longitudinal force is set soft, so that the steering stability of the vehicle is secured. While maintaining good ride comfort, the effect is easily achieved.

In addition, the upper link and the lower link are each configured by a pair of arms, so that the virtual kingpin axis KP is formed.
Is set substantially upright, and the kingpin offset at the ground contact surface of the wheel 1 and the center WO is extremely small. Therefore, the moment force acting around the virtual kingpin axis KP is reduced, and the steering force or the steering for the change in the driving and braking forces is reduced. A change in force can be suppressed, and an effect of reducing a steering force due to a change in road surface, a change in steer force due to mounting of a chain, and vibration such as shimmy can be obtained.

Furthermore, the camber angle changes in the negative direction in the turning outer wheel and the camber angle changes in the positive direction in the turning inner wheel due to the vehicle width direction displacement of the upper and lower knuckles during steering, so that the camber angle change when turning the vehicle is reduced. The effect of suppressing the grounding of the wheels is improved and the turning performance is improved.

In addition, since the displacement of the upper portion of the knuckle 2 during steering is small, it is possible to suppress an increase in the size of the wheel house, and to achieve an effect of being excellent in space efficiency and vehicle mountability.

Further, since the number of casters on the turning inner wheel side increases during steering, the steering wheel returning force can be efficiently secured, while the caster angle at the time of straight traveling is small, so that the steerability of the vehicle is improved.

In addition, since the steering wheel return force is set on the turning inner wheel side, the displacement of the instantaneous center point of the lower link system can be set relatively large, so the distance between the ball joints GN and AN needs to be set extremely small. Without
There is an advantage that the arrangement of the ball joints GN and AN becomes easy.

Furthermore, since the displacement of the instantaneous center point of the lower link system is set to be relatively large as the setting for obtaining the steering wheel return force on the turning inner wheel side, the displacement of the instantaneous center point of the upper link system can be set small. Moreover, since the upper link system is installed above the wheel 1, the length of the upper link in the vehicle width direction can be set relatively long.
The camber change and the tread change with respect to the vertical stroke of the wheel are reduced.

It should be noted that the present invention is not limited to the above-described embodiment at all, and it is needless to say that various modifications can be made without departing from the spirit of the present invention.

(Effects of the Invention) As described above in detail with the embodiment, according to the present invention, the caster angle can be positively controlled by displacing the virtual kingpin axis at the time of steering, and at the same time, at the time of steering. Since the movement of the knuckle can be reduced and the expansion of the wheel house can be suppressed, a steering wheel suspension for a vehicle whose caster angle is controlled in accordance with the steering of the wheel is provided without deteriorating space efficiency and in-vehicle mountability. It has the effect of doing.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an embodiment of the present invention, and FIG.
FIG. 3 is a schematic rear view of FIG. 1, FIG. 4 is an operation explanatory view of a lower link system, FIG. 5 is an operational explanatory view of an upper link system, and FIG. 6 is a plane of a virtual kingpin axis. It is operation | movement explanatory drawing which shows the displacement in vision. 1 ... wheel, 2 ... knuckle, 6 ... lateral arm, 7 ... compression arm, 9 ... lateral arm, 10 ... tension arm, KP ... virtual kingpin axis

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-61-218408 (JP, A) JP-A-63-116914 (JP, A) JP-A-2-57413 (JP, A) JP-A-2- 3503 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) B60G 3/18-3/26

Claims (1)

(57) [Claims] 1. A steering wheel suspension for a vehicle in which an upper link system and a lower link system each comprising a pair of front and rear arms are provided between a knuckle for rotatably supporting wheels and a vehicle body. Each of the arms has an inner end pivotally connected to the vehicle body and an outer end pivotally connected to the knuckle, and the upper link system inclines toward the vehicle front side from the knuckle at the straight-ahead position of the wheel. A front upper arm extending to the side, and a rear upper arm disposed in the vehicle width direction when viewed from above the vehicle body at the straight-ahead position, and a distance between outer ends of the front and rear upper arms is greater than a distance between inner ends. The lower link system includes: a front lower arm disposed in a vehicle width direction when viewed from above the vehicle body at the straight traveling position; A rear lower arm that is inclined toward the vehicle rear side from the knuckle and extends toward the vehicle body, and a distance between the outer ends of the front and rear lower arms is set to be smaller than a distance between the inner ends. The outer end is located on an extension of the rear upper arm in the straight-ahead position, and is located outside the outer end of the rear upper arm in the vehicle width direction, and the outer end of the rear lower arm is in the straight-ahead position. ,
Outside of the outer end of the front lower arm in the vehicle width direction, and
A suspension for a steered wheel of a vehicle, which is located on the rear side of the vehicle and configured to increase the number of casters on a turning inner wheel side during steering.