JPH0775931B2 - MacPherson strut suspension - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a MacPherson strut suspension for a vehicle, and more particularly to a suspension used for front wheel suspension and connected to a steering device.

(Prior Art) In a MacPherson strut suspension, a strut upper part of a strut having a strut upper part and a strut lower part slidable relative to the strut upper part is swingably connected to a vehicle body, and the strut lower part is laterally connected to the vehicle body. It is configured by swingably connecting to a suspension arm extending in the direction.

This suspension has features such as a small number of attachment points to the vehicle body and the only lateral member is the suspension arm, so the input to the vehicle body is small and the influence of working accuracy on the suspension geometry is small. In addition, it has advantages such as less lateral space limitation. On the other hand, since there is little change in the camber of the tire when bouncing, the ground camber of the turning outer wheel becomes large on the positive side.

Various proposals have been made for increasing the camber change of a tire at the time of bounce, for example, as shown in FIG.
56-82613) and FIG. 14 (JP-A-63-28707).

In the suspension shown in FIG. 13, the strut upper portion 21 of the strut 20 is swingably connected to the vehicle body 23, and the strut lower portion 22 slidable relative to the strut upper portion 21 is rocked on the suspension arm 24 extending in the lateral direction of the vehicle body. While being movably connected, the portion of the wheel carrier 25 above the rotation axis of the wheel is swingably connected to an assist link 27 via a ball joint 26.
Is swingably connected to the strut lower portion 22, and a portion of the wheel carrier 25 below the rotation axis is swingably connected to the suspension arm 24 via a ball joint 28.

In the suspension shown in FIG. 14, the strut upper portion 21 of the strut 20 is swingably connected to the vehicle body 23, and the strut lower portion 22 is rocked to a portion extending above the L-shaped suspension arm 30 extending upward from the lateral direction of the vehicle body. While movably connected, the portion above the rotation axis of the wheel carrier 31 formed in a U-shape when viewed from the rear is located at the lower part of the strut.
A portion of the wheel carrier 31 below the rotation axis is swingably connected to a corner of the suspension arm 30.

By the way, in order to cope with higher performance of front-wheel drive vehicles, so-called FF vehicles, for example, by installing a turbocharged engine, the front wheels rotate around the kingpin axis during sudden acceleration or deceleration. It is necessary to suppress the attempt as much as possible and ensure the steering stability.

By the braking force acting on the center of the contact surface of the tire, the front wheels are
It attempts to rotate backwards around the kingpin axis and also to rotate forward around the kingpin axis due to the driving force acting at the point where an imaginary vertical plane passing through the center of the tire ground contact plane intersects with the tire rotation axis. The degree of rotation of the former depends on the magnitude of the kingpin offset given by the distance from the intersection of the kingpin axis with the contact surface to the center of the contact surface of the tire, and the degree of rotation of the latter passes through the center of the contact surface of the tire. The distance from the intersection of the virtual vertical plane and the axis of rotation of the tire to the kingpin axis depends on the size of the so-called IK distance.To prevent the front wheel from rotating about the kingpin axis, the kingpin offset and IK The distance must be zero, or as close to zero as possible.

(Problems to be solved by the invention) In the case of FIG. 13, the kingpin axis is the ball joint 26.
It is given as a line connecting the center of and the center of the ball joint 28. As is clear from the figure, in order to make the kingpin offset L ₁ zero and the IK distance L ₂ as close to zero as possible, the ball joint 26 and the ball joint 28 are used.
May be arranged laterally outward of the vehicle body.

However, the upper ball joint 26 is
It must be placed in a predetermined inward position with respect to the lower ball joint 28 in order to provide the kingpin tilt required to provide the restoring force from the tire to the steering wheel. Further, the lower ball joint 28 is in a state of being set to a large swing angle from the viewpoint of achieving the original purpose of increasing the change in camber angle, and when the suspension arm 24 bounces and rebounds, it is substantially the same as the swing angle. Since they are oscillated by the same angle and are largely displaced laterally, the ball joint 28 is limited to the outside to avoid interference between the suspension arm 24 and the wheel brake device. .

The suspension shown in FIG. 14 has the same problem.

The object of the present invention is to make it possible to increase the camber change, to reduce the swing angle of the ball joint arranged below the wheel carrier, to make the kingpin offset substantially zero, and to reduce the IK distance as much as possible. It is to provide a MacPherson strut suspension.

(Means for Solving the Problem) According to the present invention, the strut upper part of a strut having a strut upper part and a strut lower part slidable relative to the strut upper part is swingably connected to a vehicle body, and the strut lower part is , A MacPherson strut suspension that is swingably connected to a suspension arm extending in the lateral direction of the vehicle body, and has a portion above and below the rotation axis of the wheel, with the upper portion via a ball joint. And a wheel carrier swingably connected to the lower part of the strut, one end of which is swingably connected to the suspension arm, and the other end of which swings to a lower portion of the wheel carrier via a ball joint. A control link movably connected to the control link and the suspension. The connection point with the pension arm is provided at a position that is displaced outward in the lateral direction of the vehicle body as the suspension arm swings in the bounding direction from the reference state.

Two preferred embodiments are given. In one aspect, the control link forms a rotating pair with the suspension arm at one end, the inner end, and a spherical pair with the wheel carrier at the outer end. In this aspect, the kingpin axis is provided as a line connecting the respective centers of ball joints located above and below the wheel carrier.

In another aspect, the control link consists of two rods. Each rod forms a spherical pair with the suspension arm at the inner end and a spherical pair with the wheel carrier at the outer end. In this aspect, the kingpin axis is with the center of the ball joint located above the wheel carrier,
It is given as a line connecting the intersection of the extension lines of the axes of the two rods, and is, so to speak, a virtual kingpin axis.

(Operation and Effect) When the tire becomes bound and the suspension arm swings, the strut swings, and at the same time, the control link pushes the lower portion of the wheel carrier outward in the lateral direction of the vehicle body. The wheel carrier oscillates around the upper ball joint as it is pushed outward by the control link, but the oscillating strut is also added to the wheel carrier, increasing the overall oscillating angle and Makes a great camber change.

When the tire is bound and the suspension arm swings, for example, in the suspension shown in FIG. 13, the lower ball joint swings at an angle substantially equal to the swing angle of the suspension arm. Since the control link is pushed laterally outward along with the swing, the ball joint at the connecting portion between the control link and the wheel carrier is displaced substantially laterally, and the swing angle of the ball joint is small.

Since a large negative camber change can be given to the tire at the time of bouncing, the tire can be evenly contacted with the road surface.

Since the swing angle of the ball joint located below the wheel carrier is small, the ball joint can be arranged as laterally as possible outside the vehicle body without interfering with the wheel brake device. It is possible to reduce the kingpin offset to zero and shorten the IK distance as much as possible. As a result, when the front wheels receive a braking force or a driving force, it is possible to prevent the front wheels from attempting to rotate around the kingpin axis line, and it is possible to improve steering stability while achieving high performance.

The kingpin axis can be set independently, increasing the flexibility of suspension geometry design.

(Embodiment) The MacPherson strut suspension according to the present invention is basically constructed as shown in FIG. In this suspension, the strut 40 consists of a shock absorber having a structure known per se, and the strut upper part
41 and a lower strut 42. A coil spring (not shown) is arranged between the strut upper portion 41 and the strut lower portion 42. Suspension arm 44, lower strut 42,
The strut upper portion 41 and the vehicle body 46 constitute a first four-bar link.

An axis about which the suspension arm 44 and the vehicle body 46 rotate to form a kinematic pair
48 and the axis 50 around which the suspension arm 44 and the lower part of the strut 42 circulate and pair, but need not be horizontal. The support 52 forming a spherical pair between the strut upper portion 41 and the vehicle body 46 and the axis of the cylinder 43 forming a sliding pair between the strut upper portion 41 and the strut lower portion 42 form an axis 48.
And in an imaginary plane perpendicular to the axis of axis 50.

The suspension arm 44, the control link 54, the wheel carrier 56 and the lower strut 42 form a second four-bar link. In this four-bar link, the suspension arm 44 and the control link 54 form a rotating pair with respect to the shaft 60. The axis 60 may be substantially parallel to the axis 50.

The wheel carrier 56 has a portion 57 that is above the rotation shaft 64 of the tire 62 and a portion 58 that is below the rotation shaft 64. The kingpin axis is the center of a ball joint 66 where the upper portion 57 of the wheel carrier and the lower strut portion 42 form a spherical pair.
Wheel carrier lower part 58 and control link 54
And are given as a line connecting the center of the ball joint 68 forming a spherical kinematic pair.

FIG. 2 shows the suspension of FIG. 1 in a working state. The description of the structure of this suspension which is substantially the same as that of FIG. 1 is omitted.

The suspension arm 44 is bifurcated, and rubber bushes (not shown) are arranged at the bifurcated ends 44a and 44b. The suspension arm 44 swings on the vehicle body 46 by a shaft 48 penetrating the bushes. Connected as possible. A rotation pair of the suspension arm 44 and the vehicle body 46 with respect to the axis 48 is formed by forming the suspension arm 44 with a substantially straight rod, and connecting a strut bar for restricting the longitudinal movement of the vehicle body to the wheel carrier 56. Can also be secured by.

The lower strut 42 is bifurcated, and rubber bushes (not shown) are arranged at the two branched ends 42a and 42b. The lower strut 42 has a shaft 50 passing through these bushes.
It is swingably connected to the suspension arm 44 by. This ensures a rotational pair of the lower strut 42 and the suspension arm 44 about the axis 50.

A bracket 45 protruding downward is provided at a portion of the suspension arm 44 which is located inward of the shaft 50 in the lateral direction of the vehicle body. The shaft 60 is supported by the bracket 45. On the other hand,
The control link 54 is bifurcated and bifurcated 2
Rubber bushes (not shown) are arranged at the two ends 54a, 54b, and the control link 54 is swingably connected to the bracket 45, and thus the suspension arm 44, by a shaft 60 passing through the bushes. As a result, the axis 60 of the suspension arm 44 and the control link 54
The kinematic pair is secured.

The connection point between the suspension arm 44 and the control link 54 is laterally outward from the vehicle body as the suspension arm 44 swings in the bounding direction from the standard state such as when the suspension arm 44 is not bound or rebounded during standard loading. It is provided at a position that is displaced toward. In the illustrated embodiment,
The above structure is secured by projecting the bracket 45 downward from the suspension arm 44 and connecting the control link 54 to the bracket 45 via the shaft 60. In this case, the axis of the shaft 60 becomes the connecting point.

The wheel carrier 56 is a steering knuckle, and a knuckle arm 70 is provided on the upper portion 57. Knuckle arm 70 is tie rod 74 via ball joint 72
The tie rod 74 is connected via a ball joint 76 to a member such as a rack bar of a steering device (not shown).

In FIG. 3 showing the basic constitution of another embodiment of the MacPherson strut suspension, a constitution different from the suspension shown in FIG. 1 will be explained.

The control link 84 is composed of a first rod 85 and a second rod 86. Both rods 85, 86 are arranged at substantially the same level in rear view, and are equivalent to one control link. Suspension arm 44, control link 84, wheel carrier 56 and lower strut 42
Constitutes the second 4-section link.

The suspension arm 44, the first rod 85, the wheel carrier 56 and the second rod 86 constitute a third four-bar link. In this four-bar link, the center of a ball joint 88 in which the first rod 85 and the suspension arm 44 form a spherical pair, and the center of a ball joint 90 in which the first rod 85 and the lower portion 58 of the wheel carrier 56 form a spherical pair. A straight line connecting the center and the center of a ball joint 92 where the second rod 86 and the suspension arm 44 form a spherical pair, and a ball joint 94 where the second rod 86 and the lower portion 58 of the wheel carrier 56 form a spherical pair. The point of intersection with a straight line connecting the center of is the virtual rotation center P. The virtual center of rotation P is determined so as to be located outward of the ball joints 92 and 94 in the lateral direction of the vehicle body when viewed from the rear.

The kingpin axis is a ball joint 66 in which the upper portion 57 of the wheel carrier and the lower strut portion 42 form a spherical pair.
It is given as a line connecting the center of P and the virtual rotation center P.

FIG. 4 shows the suspension of FIG. 3 in a working state. 2 or 3 in this suspension
Descriptions of the configurations that are substantially the same as those in the figure are omitted.

In place of the bracket from the suspension arm 44, two arm portions 96 and 97, which are spaced from each other in the front and rear direction, are projected downward, and the arm portion 96 is connected to the first rod 85 via the ball joint 88 and to the arm portion. 97 is connected to the second rod 86 via the ball joint 92.

The lower part 58 of the wheel carrier 56 is bifurcated, one end 58a of which is branched to the first rod 85 via the ball joint 90, and the other end 58b to the first rod 85 via the ball joint 94. It is connected to two rods 86.

The connection point between the suspension arm 44 and the control link 84 is laterally outward from the vehicle body as the suspension arm 44 swings in the bounding direction from the standard state such as when the suspension arm 44 is not bound or rebounded during standard loading. It is provided at a position that is displaced toward. In the illustrated embodiment,
The above structure is ensured by projecting two arm portions 96, 97 downward from the suspension arm 44 and connecting the two rods 85, 86 of the control link 84 to these arm portions via ball joints 88, 92. ing. In this case, the line connecting the centers of the ball joint 88 and the ball joint 92 becomes the connection point.

The operation of the first embodiment will be described below with reference to FIG. 5 in a rear view and FIG. 6 showing the movement of each component with reference to the lower part of the strut.

In FIGS. 5 and 6, the solid line indicates the reference state,
The broken line indicates the bound state. When the strut upper part 41 makes a clockwise θ ₁ rotation from the reference state around the ball joint 52 with the bounce, the suspension arm 44
With respect to the lower portion 42 of the strut about the axis 50, and rotates by θ ₂ counterclockwise from the reference state. Then, the shaft 60 rotates by θ ₂ counterclockwise about the shaft 50 with respect to the lower portion 42 of the strut,
In order to move the ball joint 68 to the right through the control link 54, the wheel carrier 56 rotates with respect to the lower strut 42 by θ _{3 in the} clockwise direction from the reference state around the ball joint 66. Further, the tire 62 rotates θ ₄ clockwise from the reference state.

If each angle when facing in the above-mentioned direction is positive, θ ₄ =
The relationship of θ ₁ + θ ₃ is established, and θ ₄ is the camber change obtained by the present invention. With the conventional MacPherson strut suspension, only a camber change of θ ₁ was obtained, but according to the present invention, the angle θ
A camber change with a correction angle of ₃ is obtained. The correction angle θ _{3 in} this case depends on the positional relationship of the shaft 60 with respect to the shaft 50, in other words, the distance R from the shaft 50 to the shaft 60 and the angle θ _{5 at} which the straight line connecting the shaft 50 and the shaft 60 is a vertical line. Greatly affected.

The 10th angle change due to bounce and rebound
As shown in the figure, the camber angle θ _{4 in} the case of the present invention
It can be seen that is changing from a positive value at rebound to a negative value at bound almost linearly. The broken line θ ₁ is the camber angle change of the conventional MacPherson strut suspension.

Next, regarding the kingpin axis, the swing angle of the ball joint 68 accompanying the bounce is approximately equal to the swing angle of the suspension arm 44 in the conventional MacPherson strut suspension, as shown in FIG. However, in the present invention, it is smaller than the conventional one. As a result, the ball joint 68 can be arranged as laterally as possible in the lateral direction of the vehicle body, and the kingpin tilt angle can be reduced to a required limit with the kingpin offset being zero. This means that the inter-IK distance L ₂ can be reduced.

The operation of the second embodiment is as shown in FIG. 7 in a rear view and FIG. 8 showing the movement of each component with reference to the lower part of the strut. Since the solid line indicates the reference state, the broken line indicates the bound state, and the orientation measured from the reference state at each angle is the same as that of the first embodiment, detailed description will be omitted.
In FIGS. 7 and 8, ball joints 88 and 92 are used instead of the shaft 60, rods 85 and 92 are used instead of the control link 54.
86 is shown, and ball joints 90, 94 are shown in place of shaft 68.

In FIG. 9 comparing the kingpin axis of the MacPherson strut suspension of the second embodiment according to the present invention with the kingpin axis of the conventional MacPherson strut suspension, in the second embodiment, the kingpin axis K ₁ is the wheel. While it is given by the line connecting the center of the ball joint 66 above the carrier and the virtual center of rotation P, in the conventional case, the kingpin axis K ₂ is a ball arranged at the connecting portion of the strut upper portion 41 with the vehicle body. It is given by a line connecting the center of the joint 52 and the center of the ball joint 100 arranged at the connecting portion between the suspension arm 44 and the lower portion of the wheel carrier 56. As is clear from this figure, the kingpin offset is zero in the second embodiment, but L ₁
Therefore, the conventional one has L ₂ larger than L ₃ with respect to the inter-IK distance L ₃ of the second embodiment.

Next, the action and effect of the present invention will be confirmed from another viewpoint.

As shown in FIG. 11, in the case of the present invention, the wheel carrier
The momentary center of the 56 with respect to the vehicle body is the T point, but the momentary center of the wheel carrier in the case of the conventional MacPherson strut suspension is the S point, and in the case of the present invention, the momentary center approaches the wheel carrier 56. Therefore, the change in camber angle of the wheel carrier viewed from the vehicle body is larger in the present invention.

In FIG. 12, the straight line connecting the ball joint 50 and the ball joint 66 is a, the straight line connecting the ball joint 50 and the shaft 60 is b, the control link 54 is c, and the wheel carrier 56 is d. The instantaneous center of the member c with respect to the member a is the intersection 99 of the extension line of the member b and the member d.

When the swing angle Δθ ₆ of the member c is represented by Δθ ₂ , Becomes Here, l (i-j) is the distance between i and j.

On the other hand, between Δθ ₆ and −Δθ ₃ , And the relationship of Δθ ₇ = Δθ ₃ + Δθ ₆ . If Δθ ₇ is expressed using Δθ ₂ , Becomes Here, since member b and member d are arranged almost vertically, even if member c is inclined, l _(60-99) and l _(68-99)
Is almost equal to. Therefore, Because of the structure, l _(50-60) is _shorter than l _(60-99) and l _(66-68) , Therefore, in the case of the present invention, it can be seen that the swing angle of the ball joint 68 is smaller than that of the conventional MacPherson strut suspension.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a basic configuration of a first embodiment of a MacPherson strut suspension according to the present invention, and FIG.
FIG. 1 is a schematic view showing the embodiment of FIG. 1 in an operating state, FIG. 3 is a schematic view showing the basic constitution of a second embodiment of a MacPherson strut suspension according to the present invention, and FIG. 4 is that of FIG. FIG. 5 and FIG. 6 are schematic views in the operating state, FIG. 5 and FIG. 6 are rear views showing the action of the MacPherson strut suspension shown in FIG. 1 and FIG. 2, and FIG. 7 and FIG. The rear view showing the action of the MacPherson strut suspension shown in the figure, FIG. 9 is the rear view showing the effect of the MacPherson strut suspension shown in FIGS. 3 and 4, and FIG. 10 is the camber obtained by the present invention. FIG. 11 and FIG. 12 are schematic diagrams showing the effect of the MacPherson strut suspension according to the present invention. FIG. 13 and FIG. It is a schematic diagram of a Pherson strut suspension. 40: Strut, 41: Upper strut, 42: Lower strut, 44: Suspension arm 48, 50, 60: Shaft, 54, 84: Control link, 56: Wheel carrier, 66, 68, 88, 90, 92, 94: Ball joint.

Claims (1)

[Claims] 1. A suspension in which a strut upper portion of a strut having a strut upper portion and a strut lower portion slidable relative to the strut upper portion is swingably connected to a vehicle body, and the strut lower portion extends laterally of the vehicle body. A MacPherson strut suspension that is swingably connected to an arm and has a portion above and below a rotation axis of a wheel, the upper portion of which can swing to the lower portion of the strut via a ball joint. And a control link that is swingably connected to the suspension arm at one end and swingably connected to a lower portion of the wheel carrier via a ball joint at the other end. And a connection point between the control link and the suspension arm , As the suspension arm swings from the reference state in the bound direction, provided at a position displaced toward the outside of the vehicle body in the lateral direction, MacPherson strut type suspension.