JP2004203195A - Suspension link - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a suspension link capable of reducing the manufacturing cost and considerably decreasing the total weight thereof while ensuring excellent function not inferior to that of a known X-link. <P>SOLUTION: Leaf spring pieces 16 and 17 vertically overlap in a facing state to constitute a first I-shaped piece 18, and leaf spring pieces 19 and 20 vertically overlap in a facing state with the first I-shaped piece held therebetween to constitute a second I-shaped piece 21. Longitudinal center portions are intersected with each other and turnably connected to each other by pins 22 and 22'. A pair of elastic brackets 25 face each other with a required space therebetween in the vehicle width direction, and fitted to an accelerator side so as to be inclined inwardly each other in the vehicle width direction. One end portions of the I-shaped pieces 18 and 21 are oscillatably connected to each other, the other end portions are oscillatably connected to a frame in a vehicle portion forward of the accelerator so that a rolling center PO of the vehicle body is located above the brackets 25 and below the center of gravity of a vehicle. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a suspension link.
[0002]
[Prior art]
7 and 8 show an example of a rear suspension structure in a large vehicle such as a truck or a bus. The rear suspension structure is provided below a pair of left and right frames 1 extending in the front-rear direction (left-right direction in FIG. 7) of the vehicle body. An axle 3 extending vertically (in the vertical direction in FIG. 8) and supporting the wheel 2 at both ends thereof is disposed, and a support beam 4 integrated with a lower surface near an end of the axle 3 is provided. An air spring 5 is interposed between the front and rear ends and the lower surface of the frame 1 to absorb vertical vibrations.
[0003]
Further, a bracket 6 extending downward is attached to the frame 1 further forward of the air spring 5 arranged on the front side, and a space between a lower end of the bracket 6 and an intermediate portion of the support beam 4 is provided. The vehicle body is tiltably connected by a stabilizer 7 that increases the roll rigidity of the vehicle body.
[0004]
That is, the stabilizer 7 shown here is generally referred to as a lower rod integrated type stabilizer, and is a hollow pipe (hollow shaft) rotatably installed between the lower ends of the left and right brackets 6. And an arm 9 fixed at one end to both ends of the stabilizer bar 8 and connected at the other end to a bracket 10 provided at an intermediate portion of the support beam 4 via a rubber bush. And the left and right wheels 2 are bridged in a U-shape. When the left and right wheels 2 move up and down simultaneously, the stabilizer bar 8 rotates with respect to the bracket 6 and the stabilizer 7 Although there is no particular work, when the left and right wheels 2 move up and down differently due to cornering or the like, a torsional moment acts on the stabilizer bar 8 and the reaction force causes Has become the wheel 2 so as to form acts like back to the original.
[0005]
Here, the arm 9 of the stabilizer 7 also has a function of determining the position and angle of the axle 3 as a lower torque rod, so that it is not necessary to separately provide a lower torque rod. With the arm 9 alone, it is difficult to reliably suppress the rotational moment (braking force or driving force) about the axis applied to the axle 3 and the displacement moment in the lateral direction.
[0006]
For this reason, the center upper surface of the axle 3 and the inner surfaces of the left and right frames 1 are connected by a V rod 12 functioning as an upper torque rod. More specifically, Branch ends 12a (front ends) of the V rod 12 are connected to brackets 13 extending from the inner surfaces of the left and right frames 1 through rubber bushes, and the center of the V rod 12 is bent. The end 12b (rear end) is connected to a bracket 14 provided above the center of the axle 3 via a rubber bush.
[0007]
If such a V-rod 12 is employed, it is possible to respond to the input in both the front-rear direction and the left-right direction of the vehicle body, so that a parallel link type torque rod is employed. There is no need to separately arrange a lateral rod as a countermeasure for input in the left-right direction, and since it is arranged offset above the lower arm 9, the rotational moment applied to the axle 3 around the axis can be reliably reduced. It becomes possible to suppress.
[0008]
A midway portion of the support beam 4 and the frame 1 immediately above the support beam 4 are connected by a shock absorber 11 extending in the vertical direction, and the shock absorber 11 suppresses the rebound of vibration in the vertical direction. The vibration is damped.
[0009]
On the other hand, in recent years, as a new suspension link replacing the above-described V rod 12, an X link 15 integrally formed so that the overall planar shape forms an X shape as shown in FIG. 9 has been proposed. According to the X-link 15 having such a planar shape, it is possible to respond to an input in both the front-rear direction and the left-right direction of the vehicle body as in the case of the conventional V-rod 12 and to use the left and right by cornering or the like. When the wheels 2 (see FIGS. 7 and 8) move up and down differently, a torsional moment acts, and acts as a stabilizer that returns the left and right wheels 2 to the original state by the reaction force. Therefore, the lower rod-integrated stabilizer 7 as shown in FIGS. 7 and 8 is not required, and can be replaced with a simple parallel link type torque rod.
[0010]
[Problems to be solved by the invention]
However, in the past, since the X-link 15 was manufactured as an integrally molded product by forging, there was a problem that the manufacturing cost was high, and the overall weight was large, and the workability at the time of assembly was high. There was a problem that became worse.
[0011]
The present invention has been made in view of the above-mentioned circumstances, and has a new function that can reduce the manufacturing cost and significantly reduce the overall weight while securing excellent functions not inferior to the conventional X-link. The purpose is to provide suspension links.
[0012]
[Means for Solving the Problems]
According to the present invention, a first leaf spring piece and a second leaf spring piece face each other up and down to form a first I-piece, and the first I-piece is sandwiched therebetween. The third leaf spring piece and the fourth leaf spring piece are vertically overlapped in a state of facing each other to form a second I-piece, and each of the first and second I-pieces is attached to each other. The central portions in the longitudinal direction are arranged so as to intersect with each other, and the intersecting portions are tiltably connected by pins penetrating in the up-down direction, while a pair of elastic brackets face each other at a required interval in the vehicle width direction and are mutually opposed to each other. Attached to the axle side so as to incline inward in the width direction, one end of each of the first and second I-shaped pieces is swingably connected to each of the brackets, and the first and second I-shaped pieces are connected. The other end of each piece is in front of the axle in the vehicle A suspension that is swingably connected to the frame and that the rolling center of the vehicle body determined by the tilting posture of each bracket is arranged above each bracket and below the center of gravity of the vehicle. Link.
[0013]
Thus, the X-shaped suspension link is constituted only by assembling the first to fourth leaf spring pieces which can be manufactured at low cost by using the ordinary leaf spring production process. Therefore, the manufacturing cost can be significantly reduced as compared with the case where an X-shaped integrally molded product is manufactured by forging.
[0014]
If the height of the first and second I-pieces is set to be slightly larger than the height of the cross-section of each arm portion of the conventional X-link, the distance between the upper and lower leaf spring pieces can be reduced. Is a gap, and the total cross-sectional area of each other is smaller than the cross-sectional area of each arm portion of the conventional X-link, the substantial second moment of area (the geometrical bending of the beam cross-section with respect to the bending moment) Since there is no significant difference in the numerical value representing the difficulty), it is possible to significantly reduce the overall weight without lowering the strength as compared with the X-link of an integrally molded product by forging.
[0015]
In particular, the first to fourth leaf spring pieces have higher toughness as compared with a normal leaf material, and the intersections of the first and second I-shaped pieces are tiltably connected to each other to reduce shear stress. It is designed so that it does not act, so that each leaf spring piece has a structure with less burden that only needs to respond to simple bending stress, and it is in a state of facing each I-shaped piece, The rational arrangement is adopted so that when one of the upper and lower parts is compressed and deformed, the other is tensilely deformed. It becomes possible to plan.
[0016]
In addition, one end of each I-shaped piece is swingably connected to the axle via a pair of elastic brackets, and the rolling center of the vehicle body is adjusted by the tilting posture of each bracket. Since it is arranged above the bracket and below the position of the center of gravity of the vehicle, the position of the center of the rolling, which is the starting point of the rolling of the vehicle body, is higher than before and the distance between the center of gravity of the vehicle and the distance between the centers of the vehicles are shorter, When rolling, an anti-rolling moment acts to significantly suppress the generation of a rolling moment.
[0017]
When the generation of the rolling moment is remarkably suppressed as described above, the torsional moment that each I-shaped piece must bear to fulfill the function as a stabilizer at the time of cornering is greatly reduced. It is possible to further reduce the size and weight of the piece.
[0018]
Further, in the present invention, it is preferable that each bracket is also tilted to the rear of the vehicle so that the center of compliance steer determined by the tilting posture of each bracket is disposed rearward of the vehicle than the axle. When a reaction force acts on the ground contact portion of the wheel from the road surface in the opposite direction to the centrifugal force during cornering, the compliance steer appears in an understeering tendency such that it turns to the turning side with respect to the center of the vehicle in top view, and this understeering tendency The rollover steer is canceled by the compliance steer.
[0019]
That is, regardless of the type of the existing suspension that is generally used, the axle trajectory is set to be slightly inclined backward from the viewpoint of improving ride comfort by reducing road impact input. When a centrifugal force acts on the anti-turning side during cornering and rolling occurs, the turning side of the vehicle body rises up against the axle and the anti-turning side sinks, and the axle moves on the backward inclined track on the turning side where the vehicle body lifts up. On the anti-turn side where the vehicle body sinks, the axle relatively rises on the backward tilted track and displaces rearward, and the entire axle turns counterclockwise with respect to the center of the vehicle in top view. Axle steer is generated by leaning toward the side, which tends to cause rollover steer, which reduces the turning radius in the steering direction determined on the front side.
[0020]
Therefore, if rollover steer, which is a common problem with such existing suspensions, can be suppressed by setting a compliance steer that tends to understeer, it can greatly contribute to improving steering stability during cornering. .
[0021]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0022]
FIGS. 1 to 6 show an embodiment of the present invention. As shown in FIGS. 1 and 2, in the suspension link of this embodiment, a first leaf spring piece 16 and a second leaf spring are used. The first I-shaped piece 18 is formed by vertically stacking the pieces 17 facing each other, and the third leaf spring piece 19 and the fourth A second I-shaped piece 21 is formed by vertically stacking the spring pieces 20 facing each other, and each of the first and second I-shaped pieces 18 and 21 intersects with each other at the longitudinal central portions thereof. And are connected in a tiltable manner by pins 22 and 22 ′ having a double pipe structure penetrating the crossing portion in the vertical direction.
[0023]
Here, the first to fourth leaf spring pieces 16, 17, 19, and 20 are all formed to have substantially the same shape as shown in FIG. Eyes 16a, 17a, 19a, and 20a are formed at one end in the longitudinal direction of each of the leaf spring pieces 16, 17, 19, and 20 at the other end in the longitudinal direction. The eyes 16b, 17b, 19b, and 20b are formed so as to be shifted to one side in the width direction so as to be opposite to the one end side, and when they are overlapped with each other in a state where they face each other, The eye 16a and eye 17a, the eye 16b and eye 17b, the eye 19a and eye 20a, and the eye 19b and eye 20b are arranged side by side in the width direction without interference to form a boss portion.
[0024]
Further, through holes 16c, 17c, 19c, and 20c are formed in the center portions in the longitudinal direction of the leaf spring pieces 16, 17, 19, and 20 to allow the pins 22, 22 'to slidably pass therethrough. As shown in FIG. 4, the upper and lower ends of each of the leaf spring pieces 16, 17, 19, and 20 are crushed through the tubular rivets forming the pins 22 and 22 ′ in a state where they are matched with each other, so that Each of the I-shaped pieces 18 and 21 is held on each of the pins 22 and 22 'so as to be connected to be tiltable.
[0025]
When the X-type link mechanism configured as described above is installed between the frame 1 side and the axle 3 side, the eye 16a is connected to one end of each of the first and second I-type pieces 18 and 21. , 17a and 19a, 20a are fitted with swinging pins 24 via rubber bushes 23, and both ends of each swinging pin 24 are attached to the axle 3 side of the bracket 25. It is designed to be connected to the upper end.
[0026]
Here, the bracket 25 is made of a leaf spring material or the like and has elasticity so as to form an S-shaped side shape as shown in FIG. 1, and has a vehicle width across an intermediate portion of the axle 3. Are mounted on the axle 3 so as to face each other at a required interval in the direction and incline inward in the vehicle width direction, and in the present embodiment, the brackets 25 are set so as to also incline toward the rear of the vehicle. .
[0027]
On the other hand, a cylindrical boss formed by the eyes 16b, 17b and 19b, 20b at the other end of each of the first and second I-shaped pieces 18, 21 swings through a rubber bush (not shown) in the same manner as described above. A moving pin is inserted and mounted, and both ends of each rocking pin are connected to the left and right frames 1 via brackets. Parts should just be adopted.
[0028]
Furthermore, the intersection of the line segment from the left and right extending upward so as to pass through the center of each rubber bush 23 on one end side of the first and second I-shaped pieces 18 and 21 and to follow the tilting posture of each bracket 25. P _O is retracted by X from the connection position between one end of each of the first and second I-shaped pieces 18, 21 and each bracket 25 to the rear of the vehicle, and the position of the first and second I-shaped pieces 18, 21 is reduced. is arranged at a position raised by Z upward from the connecting level between the one end and the bracket 25, determines the vehicle body rolling center axis P _R of the intersection point P _O to a position that passes through the longitudinal direction of the vehicle, the intersection point P _O vertically being adapted to the body of the compliance steer the central axis P _C is determined in a position through which, in the present embodiment, as shown in FIG. 5, the rolling center axis P _R is and the vehicle center of gravity G in above said each bracket 25 than It disposed towards, moreover, as shown in FIG. 6, the compliance steer the central axis P _C is adapted to be positioned rearward than the axle 3.
[0029]
In addition, as a supplementary explanation, the rolling center when the conventional X-link is adopted is located at a height position passing through the X-shaped intersection in the vehicle front-rear direction. In the case of the V-rod, The height is such that it passes through the center bent end (rear end) of the V shape in the front-rear direction of the vehicle. The center is usually located.
[0030]
Thus, by configuring the suspension link in this manner, the first to fourth leaf spring pieces 16, 17, 19, and 20, which can be manufactured at low cost by using a normal leaf spring production process, are provided. Since the X-type suspension link can be formed only by assembling, the manufacturing cost is greatly reduced as compared with the case of manufacturing the X-type integrally molded product by forging.
[0031]
Further, if the height of the first and second I-shaped pieces 18 and 21 is set so as to be slightly larger than the height of the cross section of each arm portion of the conventional X-link, the upper and lower leaf spring pieces are set. Even if there is a gap between 16, 17, and 19, 20 and the sum of the cross-sectional areas is smaller than the cross-sectional area of each arm portion of the conventional X-link, a substantial second moment of area (bending) Since there is no significant difference in the moment, a numerical value indicating the difficulty in geometrically bending the beam cross section), the overall weight is significantly reduced without lowering the strength as compared with the X-link of an integrally molded product by forging. It becomes possible.
[0032]
In particular, the first to fourth leaf spring pieces 16, 17, 19, and 20 have higher toughness as compared with a normal leaf material, and have an intersection between the first and second I-shaped pieces 18, 21. Are connected so as to be tiltable by the pins 22 and 22 'so that no shearing stress is exerted thereon, so that the leaf spring pieces 16, 17, 19 and 20 can cope only with a simple bending stress, thereby reducing the burden. The structure is such that each I-shaped piece is facing each other, and a reasonable arrangement is adopted such that when one of the upper and lower parts is compressed and deformed, the other is pulled and deformed. Therefore, it is possible to achieve a very reasonable weight reduction under the condition that the same function as the conventional X link is secured.
[0033]
In addition, one end of each of the I-shaped pieces 18 and 21 is swingably connected to the axle 3 via an elastic bracket 25. since the rolling center P _O is are to be disposed below and the vehicle center of gravity G at higher than each of the brackets 25, the vehicle center-of-gravity position of the rolling center P _O as a base point of the vehicle body rolling is higher than the conventional The distance between G and G is shortened, and an anti-rolling moment acts during rolling, so that generation of a rolling moment is significantly suppressed.
[0034]
That is, as shown in FIG. 5, when a centrifugal force acting toward the counter-turning side during cornering and FY, the centrifugal force FY is because they act in an anti-turning side to the vehicle center of gravity G, that from the rolling center P _O Assuming that the height dimension to the vehicle center of gravity G located above is LZ, the rolling moment MO for rolling the vehicle body is given by the following equation:
MO = LZ × FY
Is represented by
[0035]
In FIG. 5, when the centrifugal force FY acts on the vehicle center of gravity G, the bracket 25 is deformed from the solid line position in FIG. 5 to the position indicated by the imaginary line, and the rolling center P _O is also shifted to the position of P _O ′ indicated by the imaginary line. Since the vehicle moves, assuming that the weight on the vehicle body acting on the vehicle center of gravity G is WZ and the amount of deviation of the rolling center P _O is LY, the anti-rolling moment MA is given by the following equation:
MA = LY × WZ
Is represented by
[0036]
Therefore, the actual rolling moment M acting on the vehicle body when the vehicle turns is represented by the following equation:
M = MO-MA = LZ × FY-LY × WZ
As a result, the rolling moment M is reduced, and an anti-rolling effect can be provided on the vehicle body side.
[0037]
When the generation of the rolling moment is remarkably suppressed in this way, the torsional moment that each I-shaped piece 18, 21 must bear in order to fulfill the function as a stabilizer at the time of cornering is greatly reduced. It is possible to further reduce the size and weight of each of the I-shaped pieces 18, 21.
[0038]
Therefore, according to the above embodiment, an X-type link mechanism having excellent functions not inferior to the conventional X-link is manufactured at low cost by assembling the first to fourth leaf spring pieces 16, 17, 19, and 20. Therefore, the manufacturing cost can be significantly reduced, and the overall weight can be significantly reduced.
[0039]
Also, since in the present embodiment is, and are configured to compliance steer central axis P _C determined by tilting posture of each bracket 25 having elasticity is disposed rearward from the axle 3, for example, as shown in FIG. 6 When the vehicle turns rightward as indicated by arrow A, the entire axle 3 is inclined so as to face the turning side with respect to the center of the vehicle when viewed from above, and axle steer occurs, whereby the steering direction determined by the front side is obtained. Even if a roll understeer is newly generated to increase the turning radius of the vehicle, as shown by the arrow B, when a reaction force acts on the ground contact portion of the wheel 2 from the road surface in a direction opposite to the centrifugal force, the compliance steer occurs. Appears in an understeer tendency that turns to the turning side with respect to the center of the vehicle when viewed from above. So that is canceled.
[0040]
That is, regardless of the type of the existing suspension that is generally used, the trajectory of the axle 3 is set to be slightly inclined backward from the viewpoint of improving the riding comfort by reducing the road impact input. When rolling occurs due to centrifugal force acting on the anti-turning side during cornering, the turning side of the vehicle lifts up against the axle 3 and the anti-turning side sinks, and the axle 3 tilts backward on the turning side where the vehicle lifts up. On the other side where the vehicle body sinks, the axle 3 relatively rises on the backward inclined track and displaces rearward, while the axle 3 is entirely displaced rearward on the anti-turn side where the vehicle body sinks. Axle steer is generated by inclining toward the anti-turn side with respect to the center, thereby easily causing rollover steer, which reduces the turning radius in the steering direction determined on the front side. In the direction.
[0041]
Therefore, if rollover steer, which is a common problem with such existing suspensions, can be suppressed by setting compliance steer with an understeer tendency, it can greatly contribute to improving steering stability during cornering. .
[0042]
It should be noted that the suspension link of the present invention is not limited to the above-described embodiment, but may be applied to various types of suspension structures, and may be variously modified without departing from the gist of the present invention. Obviously you can get it.
[0043]
【The invention's effect】
According to the suspension link of the present invention described above, various excellent effects as described below can be obtained.
[0044]
(I) According to the invention described in claim 1 of the present invention, it is possible to significantly reduce the manufacturing cost while securing excellent functions not inferior to the conventional X-link, and furthermore, to greatly increase the total weight. The weight can be reduced.
[0045]
(II) According to the second aspect of the present invention, the rollover steer can be suppressed by causing the compliance steer at the time of cornering to have an understeer tendency, thereby improving the steering stability at the time of cornering. Can be planned.
[Brief description of the drawings]
FIG. 1 is a perspective view showing an example of an embodiment of the present invention.
FIG. 2 is a schematic diagram for explaining the arrangement configuration of FIG. 1 in a simplified manner.
FIG. 3 is a single-piece drawing of each leaf spring piece of FIG. 1;
FIG. 4 is a cross-sectional view of an intersection of the suspension link of FIG. 1;
FIG. 5 is a schematic diagram illustrating the principle of generation of an anti-rolling moment.
FIG. 6 is a schematic diagram illustrating the principle of suppressing rollover steering.
FIG. 7 is a schematic diagram showing a conventional example.
8 is a view in the direction of arrows VIII-VIII in FIG. 7;
FIG. 9 is a perspective view showing an example of a conventional X-link.
[Explanation of symbols]
1 Frame 3 Axle 16 First leaf spring piece 17 Second leaf spring piece 18 First I-shaped piece 19 Third leaf spring piece 20 Fourth leaf spring piece 21 Second I-shaped piece 22 Pin 22 ′ Pin 25 Resilient bracket

Claims (2)

A first leaf spring piece and a second leaf spring piece are stacked one on top of the other in a state of facing each other to form a first I-piece, and a third leaf piece is sandwiched between the first I-piece. A leaf spring piece and a fourth leaf spring piece are stacked one on top of the other in a state of facing each other to form a second I-piece, and each of the first and second I-pieces is placed at the longitudinal center of each other. Are arranged so as to intersect with each other, and the intersecting portions are tiltably connected by pins penetrating in the vertical direction, while a pair of elastic brackets face each other at a required interval in the vehicle width direction and mutually inward in the vehicle width direction. Attached to the axle side so as to tilt, one end of each of the first and second I-pieces is swingably connected to each of the brackets, and each of the first and second I-pieces is The other end to a frame that is forward of the vehicle from the axle Suspension link to swingably connected, characterized in that the rolling center of the vehicle body determined by the tilting attitude of each bracket is configured to be disposed below and the vehicle center of gravity above said each bracket. The suspension link according to claim 1, wherein each bracket is also tilted to the rear of the vehicle, and a center of compliance steer determined by the tilting posture of each bracket is arranged rearward of the vehicle from the axle.

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