JP2725476B2 - Horizontal leaf spring suspension - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a horizontal leaf spring type suspension in which leaf springs are arranged so as to be offset behind right and left wheel centers.

[0002]

2. Description of the Related Art In a conventional horizontal leaf spring type suspension, a connecting portion between a lower arm or an upper arm and a vehicle body is located forward of a wheel center, and wheels move up and down in an arc having a center in front. The wheel is rotatably supported by a knuckle spindle. Further, the leaf springs arranged horizontally are offset rearward from the left and right wheel centers and are arranged in the vehicle width direction with the upper surface being horizontal, so that the bending directions of the leaf springs are up and down. A protruding rod extends rearward from an upper portion of the knuckle of the knuckle spindle, and an outer end of the protruding rod and one end of the leaf spring are connected via a connecting rod having a vertical axis. .

[0003]

However, in the above-mentioned horizontal leaf spring type suspension,
When the wheel bounces or rebounds, the wheel center A of the wheel strokes in an arc having a center point G in front as shown in FIG.
Also moves up and down in an arc around the center point G.

[0004] At this time, since the upper end of the connecting rod 3 and the leaf spring 4 are offset behind the wheel center A, the stroke length of the upper end of the connecting rod 3 with respect to the stroke length of the wheel center A is increased. Therefore, the amount of movement of the leaf spring 4 connected to the connecting rod 3 in the vertical direction also increases.

That is, the amount of deflection of the leaf spring 4 with respect to the stroke length of the wheel center A increases in proportion to the rearward offset value of the leaf spring 4 with respect to the wheel center A, and the input value to the vehicle body increases. There is a problem. The wheel center A strokes while drawing an arc-shaped trajectory.
Moves vertically regardless of the trajectory of the wheel center A, so that the connecting rod 3 connecting the leaf spring 4 and the knuckle spindle swings back and forth following the vertical movement of the wheel center A, This is a factor that increases friction.

The present invention has been made in view of the above-described problems, and reduces the amount of deflection of the leaf spring 4 with respect to the stroke length of the wheel center A.
The purpose is to reduce the swing of the connecting rod 3 to improve the riding comfort.

[0007]

In order to achieve the above object, a horizontal leaf spring suspension according to the present invention has a suspension geometry in which a connecting portion between an arm and a vehicle body is located forward of a wheel center. Wheels that move up and down in a circular arc trajectory centered in front,
A knuckle spindle that rotatably supports the wheels,
A projecting portion extending rearward from an upper portion of the knuckle of the knuckle spindle, a connecting rod extending downward by rotatably connecting an upper end portion to an outer end of the projecting portion, and a connecting rod extending downward. A horizontal leaf spring suspension rotatably connected to the lower end and offset rearward from the wheel center and extending in the vehicle width direction; To the connection point at the upper end of the connecting rod
Center of rotation at the connecting point of the lower end of the connecting rod.
It is characterized in that it has placed on the wheel center side of the rotation center that.

It is preferable that the upper surface of the leaf spring is inclined toward the axle so that the bending direction of the leaf spring is closer to the axial direction of the connecting rod.

[0009]

Although the offset of the leaf spring with respect to the wheel center is not changed, since the upper end of the connecting rod approaches the wheel center, the offset value of the upper end of the connecting rod with respect to the wheel center becomes smaller, and the upper end of the connecting rod with respect to the stroke length of the wheel center. The stroke length becomes smaller than before.

Therefore, the amount of deflection of the leaf spring connected to the connecting rod with respect to the stroke length of the wheel center also becomes smaller than before, and the input value to the vehicle body becomes smaller than before. Further, when the axis of the connecting rod is inclined forward and the bending direction of the leaf spring approaches the axis of the connecting rod, the swing of the connecting rod at the connecting portion between the lower end of the connecting rod and the leaf spring is reduced.

At this time, with respect to the forward inclination of the axis of the connecting rod, an arc which is the locus of the stroke of the wheel center is obtained by suspending the axis with the suspension of the vehicle load during normal use of the vehicle to which the present invention is applied. The closer to the tangential direction the direction perpendicular to the straight line connecting the center point of the connecting rod and the upper end of the connecting rod, that is, the closer the tangential direction, the larger the maximum displacement in the front-rear direction between the trajectory of the upper end of the connecting rod and the trajectory of the bending direction of the leaf spring. And the same amount between the rebound and the rebound, the displacement becomes uniform, and the swinging of the connecting rod in the front-rear direction can be reduced.

[0012]

An embodiment of the present invention will be described with reference to the drawings.
First, as shown in FIGS. 1 and 2, a knuckle spindle 1 rotatably supports a wheel 2, and a knuckle portion of the knuckle spindle 1 is bifurcated up and down to form a knuckle upper portion 1a and a knuckle lower portion 1b. Is formed.
A projecting portion 1c extends rearward from a middle portion of the knuckle upper portion 1a, and an upper end portion 3a of the connecting rod 3 is swingably connected to a rear end of the projecting portion 1c via a bush. The axis K of the connecting rod 3 is inclined forward by about 20 degrees with respect to the vertical line H, and the lower end of the connecting rod 3 is swingably connected to one end of the leaf spring 4 via a fitting. . The leaf spring 4 is offset rearward from the wheel center A, is placed horizontally in the vehicle width direction, and extends to the other wheel 2 side. The upper surface of the leaf spring 4 is inclined about 10 degrees forward with respect to the vertical direction H. The leaf spring 4
Supports the cross member 5 fixed to the vehicle body side at two symmetrical positions thereof in a swingable manner.

One end of a lower arm 6 is swingably connected to the knuckle lower part 1b of the knuckle spindle 1, and the lower arm 6 is extended toward the front side, and the other end is swingably connected to the vehicle body. doing. A lower end of a shock absorber 7 is attached to the lower arm 6, and an upper end of the shock absorber 7 is connected to a vehicle body (not shown).

The knuckle upper part 1a is swingably connected to a support member 8 on the vehicle body side via an upper arm 9. Further, in the suspension having the above-described configuration, the locus of the stroke of the wheel 2 due to the bound and rebound draws an arc having a center point G in front due to the suspension geometry such that the lower arm 6 is extended toward the front side. I have.

In the horizontal leaf spring suspension of the above construction, when the wheel 2 bounces, the wheel center A of the wheel 2 moves upward in an arc having a center point G in front as shown in FIG. Knuckle upper part 1
The upper end 3a of the connecting rod 3 connected to the a through the protruding portion 1c also moves upward in an arc centered on the center point G. Similarly, when the wheel 2 rebounds, the wheel center A of the wheel 2 moves downward in an arc having a center point G on the front side as shown in FIG. The upper end 3a of the connecting rod 3 connected via 1c also moves downward in an arc centered on the center point G.

At this time, since the upper end 3a of the connecting rod 3 is mounted closer to the upper portion 1a of the knuckle than in the prior art, the distance from the center point G to the upper end 3a of the connecting rod 3 becomes shorter, and The stroke length of the upper end 3a of the connecting rod 3 with respect to the stroke length of the center A becomes shorter than before, and the amount of deflection of the leaf spring 4 connected at the lower end of the connecting rod 3 becomes smaller than before.

That is, the amount of deflection of the leaf spring 4 with respect to the stroke length of the wheel center A is reduced without changing the offset value of the leaf spring 4 with respect to the wheel center A, and thus the input value to the vehicle body is reduced. The riding comfort of the vehicle is improved. At this time, as shown in FIG. 4, the upper surface of the leaf spring 4 is tilted toward the wheel center A (front), so that the leaf spring 4
When the bending direction S of the connecting rod 3 approaches the axis of the connecting rod 3 when a normal vehicle load is suspended by the suspension, the connecting rod 3 is connected with the lower end of the connecting rod 3 and the leaf spring 4 in front of and behind the connecting rod 3. The swing in the direction is reduced, and the occurrence of friction can be reduced.

In particular, when the axis K of the connecting rod 3 is suspended by a suspension of a normal body load in a vehicle to which the present invention is applied, the center point G of the arc which is the locus of the stroke of the wheel center A is connected to the connecting rod 3. Upper end 3
a, the maximum displacement in the front-rear direction of the upper end 3a of the connecting rod 3 with respect to the bending direction S of the leaf spring 4 is the same in both the bounce and the rebound. , And the displacement becomes uniform, so that the connecting rod 3 does not swing a lot (for example, at the time of bounce) as in the related art (see FIG. 5), and the swing of the connecting rod 3 in the front-rear direction becomes smaller, Generation of friction by the connecting rod 3 is further reduced.

If the stroke of the wheel 2 is in a suspension geometry such that the rebound is larger than the rebound than the bounce, the angle of the deflection direction S of the leaf spring 4 with respect to the vertical line H is determined by the connecting rod 3. Is slightly smaller than the inclination angle of the axis K with respect to the vertical line H, so that the maximum displacement of the connecting rod 3 upper end 3a in the front-rear direction with respect to the bending direction S of the leaf spring 4 becomes
The displacement becomes uniform by approaching the same amount at the time of bounce and at the time of rebound, and the swing of the connecting rod 3 in the front-rear direction can be reduced.

Similarly, also in the case of a suspension geometry in which the stroke of the wheel 2 is smaller during rebound than when bound, the angle of the leaf spring 4 in the bending direction S is slightly larger than the inclination angle of the connecting rod 3. This makes it possible to reduce the swing of the connecting rod 3 in the front-rear direction.

[0021]

As described above, the leaf spring type suspension according to the present invention has the advantage that the amount of deflection of the leaf spring with respect to the stroke length of the wheel center can be reduced without changing the offset value of the leaf spring from the wheel center. As a result, the input value to the vehicle body is reduced, and the riding comfort of the vehicle can be improved.

At this time, by making the bending direction of the leaf spring closer to the axis of the connecting rod which is also inclined, the swinging of the connecting rod is reduced and the occurrence of friction can be reduced.

[Brief description of the drawings]

FIG. 1 is a side view of a horizontal leaf spring suspension according to the present embodiment.

FIG. 2 is a rear view of the same.

FIG. 3 is a schematic diagram illustrating a relationship between a stroke of a wheel center and a stroke of a leaf spring in the present embodiment.

FIG. 4 is a schematic diagram showing a relationship between a stroke of a wheel center and a stroke of a leaf spring in a second embodiment.

FIG. 5 is a schematic diagram showing a relationship between a stroke of a wheel center and a stroke of a leaf spring in a conventional example.

[Explanation of symbols]

 1 Knuckle spindle 1a Knuckle upper part 1c Projecting part 2 Wheel 3 Connecting rod 4 Leaf spring 6 Lower arm 9 Upper arm A Wheel center G Center point K Axis of connecting rod S Leaf spring bending direction

Claims (2)

(57) [Claims] 1. A wheel that moves up and down in a circular locus having a forward center by a suspension geometry such that a connecting portion between an arm and a vehicle body is located forward of a wheel center, and the wheel is rotatable. A knuckle spindle to be supported, a projecting portion extending rearward from an upper portion of the knuckle of the knuckle spindle, and an upper end portion at an outer end of the projecting portion.
A connecting rod that is rotatably connected and extends downward, and a horizontally mounted leaf spring that is rotatably connected to a lower end of the connecting rod and that is offset rearward from the wheel center and extends in the vehicle width direction. In the horizontal leaf spring type suspension provided with the upper end of the connecting rod with respect to the vertical movement trajectory of the leaf spring.
Is connected to the lower end of the connecting rod.
Horizontal leaf spring suspension is characterized in that it has placed on the wheel center side of the rotation center of junction points. 2. The horizontal leaf spring suspension according to claim 1, wherein an upper surface of the leaf spring is arranged to be inclined toward the axle.