JP2000203228A - Vehicular front suspension device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To set high torsional rigidity around the link axis, and to reconcile restraint of road noise and an improvement in comfortableness by connecting both lower arm via a sub-link having the link axis arranged in the center of gravity of one lower arm or on a straight line passing through the vicinity. SOLUTION: Respective wheel side connecting parts 3a, 4a of plural lower arms 3, 4 are swingably connected to a wheel support member 2 for rotatably supporting wheels 1. One lower arm 4 is formed in an L shape curved inside in the car width direction to the link axis L2 for connecting wheel side and car body side both connecting points P21, P22 for preventing interference with the wheels at steering time. Thus, the center of gravity G of the lower arm 4 exists in a position offset to the lower arm 3 side from the link axis L2. In this case, both lower arm 3, 4 are connected by a sub-link 5, and the link axis L3 of the sub-link 5 is arranged so as to be vertical to the link axis L2 and to coincide with a straight line passing through the center of gravity G.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle front suspension device having a lower arm structure.

[0002]

2. Description of the Related Art A conventional front suspension apparatus employs, for example, a lower arm structure as shown in FIG. 13 so that a lower set point P3 of a kingpin shaft is set at a position lower than the respective wheel-side connection points P11 and P12 of the lower arms 3 and 4. Some are positioned outward in the width direction. That is, in this front suspension device, the lower arm is composed of a first lower arm 3 mainly receiving a force in the lateral direction of the vehicle and a second lower arm 4 mainly receiving a force in the longitudinal direction of the vehicle. The intersection point P3 of the straight line L1 passing through the wheel-side connection point P11 and the vehicle body-side connection point P12 and the straight line L2 passing through the wheel-side connection point P21 of the second lower arm 4 and the vehicle body-side connection point P22 is defined as the wheel of each lower arm 3, 4. This is a so-called double pivot type suspension which is located outside of the side connection points P11 and P12 in the vehicle width direction and uses this intersection point P3 as a set point below the virtual kingpin axis.

[0003] In the following description, a straight line passing through two connection points or a straight line connecting two connection points in one link member is appropriately referred to as a link axis. For example, a straight line passing through the wheel-side connection point P12 of the second lower arm 4 and the vehicle body-side connection point P22 is referred to as a link axis L2 of the second lower arm 4.

[0004]

As described above, in the front suspension device in which the lower arm is made up of the two arms 3 and 4 to regulate the lower set point P3 of the virtual kingpin axis, when the wheels are steered, In order to avoid the two lower arms 4 from interfering with the wheels, and to avoid the second lower arms 4 from interfering with the tie rods when the wheels swing up and down, the second lower arm 4 is connected to the first lower arm 3 in plan view.
It is necessary to design the shape curved to the side. As a result, the center of gravity of the second lower arm 4 is located at a position offset from the link axis L2 connecting the wheel-side connection point P12 and the vehicle-body connection point P22 to the first lower arm 3 side. Rotational displacement about the link axis L2 is likely to occur, and rotational resonance may occur at a low frequency, resulting in deterioration of road noise.

As a means for solving this problem, it is conceivable to increase the torsional rigidity of the second lower arm 4 around the connecting axis of the vehicle-body-side connecting portion 4a (for example, an elastic bush). Since the rigidity in other directions is also increased, there is a high possibility that road noise in a high frequency range is increased or riding comfort is deteriorated. Here, as a front suspension device in which the first lower arm 3 and the second lower arm 4 are connected by a sub-link 50, there is a front suspension device proposed in Japanese Patent Laid-Open No. 5-201217 as shown in FIG. The purpose is different from that of the first embodiment, and since the sub-link 50 and each of the lower arms 3 and 4 are connected via the ball joint 51, the effect of improving the torsional rigidity of the second lower arm 4 around the link axis L2. There is no.

The present invention has been made in view of the above-mentioned problems, without impairing the function as a double pivot type suspension, without increasing high frequency road noise and deteriorating ride comfort. It is another object of the present invention to provide a front suspension device capable of improving low-frequency road noise by improving torsional rigidity of a second lower arm around a link axis mainly receiving a force in a vehicle longitudinal direction.

[0007]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, an invention according to a first aspect of the present invention is directed to a wheel supporting member for rotatably supporting a wheel, and a vehicle body side connecting portion vertically swinging to a vehicle body side member. A first lower arm that is connected as possible, extends substantially in the vehicle width direction, and connects a wheel-side connecting portion to the wheel supporting member;
A second lower arm that is connected to the vehicle body-side member so as to be vertically swingable behind the first lower arm in the vehicle front-rear direction and that connects a wheel-side connection portion to the wheel support member. In a front suspension device for a vehicle, a lower set point of a virtual kingpin axis is formed by an intersection of a straight line passing through a side connection point and a wheel side connection point and a straight line passing through a vehicle body side connection portion and a wheel side connection point of a second lower arm. The first lower arm and the second lower arm are connected by a sub-link, and a straight line passing through each connection point between the first lower arm and the second lower arm in the sub-link connects the wheel side connection point and the vehicle body side connection point of the second lower arm. A front suspension device for a vehicle, which is perpendicular or substantially perpendicular to a connecting line and passes through or near the center of gravity of the second lower arm. It is intended to provide.

According to a second aspect of the present invention, a wheel supporting member for rotatably supporting a wheel and a vehicle body-side connecting portion are connected to the vehicle body-side member so as to be vertically swingable and extend substantially in the vehicle width direction. And a first connecting the wheel-side connecting portion to the wheel supporting member.
A lower arm, a second lower arm that is connected to the vehicle body-side member so as to be able to swing up and down in a vehicle front-rear direction with respect to the first lower arm and that connects a wheel-side connection portion to the wheel support member;
A lower set point of the virtual kingpin axis by an intersection of a straight line passing through the vehicle body side connection point and the wheel side connection point of the first lower arm and a straight line passing through the vehicle body side connection portion and the wheel side connection point of the second lower arm. The first lower arm and the second lower arm are connected by a sub-link, and a straight line passing through each connection point between the first lower arm and the second lower arm in the sub-link is a wheel of the second lower arm. A front suspension device for a vehicle, which is perpendicular or substantially perpendicular to a line connecting the side connection point and the vehicle body side connection point and passes through or near the center of gravity of the second lower arm.

According to a third aspect of the present invention, in addition to the configuration of the first or second aspect, the sub-link is connected to the first lower arm and the second lower arm via elastic bushes. The axis of each elastic bush is vertically oriented. Next, the invention described in claim 4 is based on claim 3
According to the configuration described in (1), at least one of the elastic bushes is press-fitted into a mounting portion on the lower arm side.

A fifth aspect of the present invention is characterized in that at least one of the elastic bushes is press-fitted into a mounting portion on the sub-link side with respect to the configuration described in the third aspect. Is what you do. Next, in the invention described in claim 6, the first lower arm and the sub-link are connected to the configuration described in claim 1 or 2 via an elastic bush whose axis is directed vertically. , The second lower arm and the sub-link are connected via a slide bearing whose rotation axis is directed vertically.

[0011] Next, according to a seventh aspect of the present invention, in the configuration according to the first or second aspect, the sub-link is provided on a first lower arm and a second lower arm, respectively.
The rotary shaft is connected via a sliding bearing with the rotating shaft directed in the vertical direction, and is extendable / contractible with respect to the sub-link along a linear direction connecting each connection point of the sub-link with the first lower arm and the second lower arm. It is characterized by providing an adjustment mechanism.

According to an eighth aspect of the present invention, in addition to the configuration of the seventh aspect, the length adjusting mechanism includes a first slide member on the first lower arm side of the sub-link and a first slide member of the sub-link. A second slide member on the side of the second lower arm, wherein both slide members are arranged with their axes oriented in the above-mentioned expansion and contraction direction, and the first slide member is relatively guided by the second stud member. Thus, relative movement is possible only in the expansion / contraction direction.

Next, a ninth aspect of the present invention is characterized in that, in contrast to the configuration of the seventh aspect, the length adjusting mechanism can be expanded and contracted by deformation of an elastic body. is there.

[0014]

According to the first aspect of the present invention, the second aspect
Since the first lower arm and the second lower arm are connected via a sub-link in which the link axis is disposed on a straight line passing through or near the center of gravity of the lower arm, the rigidity of the vehicle body-side connecting member of the second lower arm is set low. Even in this case, the torsional rigidity around the link axis connecting the wheel-side connecting portion and the vehicle-body-side connecting portion in the second lower arm can be set effectively high. As a result, there is an effect that both the suppression of low-frequency road noise and the high-frequency road noise and the suppression of deterioration in riding comfort can be effectively achieved.

Further, the link axis of the sub-link is
Since it is arranged perpendicular or substantially perpendicular to the link axis of the lower arm, the displacement about the link axis of the second lower arm and the displacement about the axis (link axis of the sub-link) perpendicular to the link axis of the second lower arm are: Do not couple. As a result, tuning of the resonance frequency of the second lower arm and the sub link is facilitated, which is advantageous in designing the low-frequency road noise performance of the second lower arm.

Next, when the invention according to claim 2 is adopted,
Even in a front suspension device in which the second lower arm is disposed forward of the first lower arm in the vehicle front-rear direction, the same operation and effect as the invention according to claim 1 can be obtained. Next, when the invention according to claim 3 is adopted, by connecting the sub-link and each lower arm via the elastic bush, respectively, the assembly error of the sub-link and each lower arm can be absorbed by the elastic bush. As a result, manufacturing becomes easy.

Further, by turning the axis of each elastic bush in the vertical direction, the relative displacement of the first lower arm and the second lower arm due to the turning can be effectively suppressed while effectively suppressing the rotational displacement of the second lower arm around the link axis. It can be absorbed by the torsional rigidity of the bush. Also, since the torsional rigidity of the elastic bush is usually considerably lower than the torsional rigidity,
A more natural snake feel can be obtained than when the bush is arranged with the axial direction coinciding with the other directions.

Next, when the invention according to claim 4 is adopted,
By press-fitting the elastic bush into the mounting portion on the lower arm side, even if the axial length of the elastic bush is increased, the influence on the link layout is reduced. In other words, the axial length of the elastic bush can be set longer. There is an effect that the torsional rigidity of the lower arm around the link axis can be effectively increased.

Next, when the invention according to claim 5 is adopted,
By pressing the elastic bush into the mounting part on the sub-link side, only the hole for bolt penetration for connection needs to be set in the mounting part of the corresponding lower arm. There is an effect that required strength can be easily secured. Next, when the invention according to claim 6 is employed, the assembly error can be absorbed by the elastic bush provided at the connecting portion between the first lower arm and the sub-link, thereby facilitating the manufacture and the displacement of both lower arms due to the snake. Since it can be absorbed, there is an effect that a natural steering feeling can be obtained.

Further, a sliding bearing having higher torsional rigidity than the elastic bush is used for the connecting portion between the second lower arm and the sub-link located near the center of gravity of the second lower arm.
There is an effect that the torsional rigidity around the link axis of the second lower arm can be further increased. Next, when the invention according to claim 7 is adopted, even if the first lower arm and the second lower arm are connected by the sub-link, each connection of the first lower arm and the second lower arm in the sub-link by the length adjustment mechanism. Since the distance between the parts can be expanded and contracted, it is possible to absorb an assembly error and a relative displacement between the two lower arms due to steering. As a result, there is an effect that the assembling becomes easy and a natural steering feeling can be obtained.

Further, since the sub-link and each lower arm are connected by a sliding bearing rotatable about the vertical axis, there is an effect that the torsional rigidity of the second lower arm around the link axis can be further increased. By adopting the invention according to claim 8, there is an effect that the length adjusting mechanism can be realized.

By adopting the invention according to claim 9, there is an effect that the length adjusting mechanism can be realized.

[0023]

Next, an embodiment of the present invention will be described. First, the configuration of the first embodiment will be described with reference to the drawings. FIG. 1 is a diagram showing a lower arm structure according to the present invention in a front suspension device disposed on the left side of a front wheel. The front suspension device arranged on the right side of the front wheel has the same configuration.

In the configuration, the wheel 1 is rotatably supported by a wheel support member 2 made of a knuckle or the like. The wheel support member 2 has a first lower arm 3 extending in the vehicle width direction.
The wheel side connecting portion 3a is swingably connected via a connecting member. The vehicle-body-side connecting portion 3b of the first lower arm 3
Is swingably connected to a vehicle body-side member (not shown) via an elastic bush. The first lower arm 3 mainly receives a force in a vehicle lateral direction.

Further, a second lower arm 4 is disposed forward of the first lower arm 3 in the vehicle longitudinal direction. The wheel-side connecting portion 4a of the second lower arm 4 is swingably connected to the wheel support member 2 via a connecting member. The vehicle body side connecting portion 4b of the second lower arm 4 is swingably connected to a vehicle body side member (not shown) via an elastic bush.

The second lower arm 4 is substantially inward in the vehicle width direction with respect to a link axis L3 connecting the wheel side connection point P21 and the vehicle body side connection point P22 in order to prevent interference with the wheel 1 at the time of turning the wheel. It is substantially L-shaped (the first lower arm 3 side). For this reason, the center of gravity G of the second lower arm 4
Is located at a position offset from the link axis L3 of the second lower arm 4 toward the first lower arm 3. Here, since the second lower arm 4 mainly plays a role of receiving a force acting on the wheel 1 in the front-rear direction of the vehicle, the member rigidity of the second lower arm 4 at the vehicle-body-side connection point P12 of the second lower arm 4 is as small as possible. It is desirable to set low.

The link axis L of the first lower arm 3
Intersection P3 between the first lower arm 4 and the link axis L2 of the second lower arm 4
Are the wheel-side connection points P11, P21 of the lower arms 3, 4.
The intersection P3 regulates the lower set point of the virtual kingpin axis. The first lower arm 3 and the second lower arm 4 are connected via a sub link 5. The link axis L3 connecting each connection point of the sub-link 5 with the lower arms 3 and 4 is substantially coincident with a straight line perpendicular to the link axis L2 of the second lower arm 4 and passing through the center of gravity G of the second lower arm 4. Are located in

Next, the configuration of the sub-link 5 and the connection structure between the sub-link 5 and the lower arms 3 and 4 will be described. As shown in FIG. 2, the sub-link 5 is a rod-shaped link member, and has a cylindrical portion 6 at each end, which forms a mounting portion. An elastic bush 7 is press-fitted into each of the cylindrical portions 6, and an inner cylinder 8 is provided on an inner diameter surface of the elastic bush 7. In addition, the connecting portion between the first lower arm 3 and the sub-link 5 is provided in FIG.
As shown in the figure, a through hole 9 whose axis is up and down is opened. Similarly to the first lower arm 3, a mounting hole with a vertical axis is opened at a connection portion of the second lower arm 4 with the sub link 5 (not shown).

The mounting hole 9 is provided above the through hole 9.
The first lower arm 3 and the sub-link 5 are connected to each other by mounting bolts 10 penetrating the inner cylinder 8 and the inner cylinder 8 in a state where the inner cylinder 8 is arranged coaxially. Reference numeral 11 denotes a nut,
Reference numeral 12 represents a washer. The sub link 5 and the second lower arm 4 are also connected in a similar configuration. Thereby, each lower arm 3, 4 and the sub-link 5
Each has a configuration in which the shafts are connected via elastic bushes 7 whose up and down directions.

Next, the operation and effects of the above configuration will be described. In the front suspension device of the present embodiment, the first lower arm 3 and the second lower arm 4 are connected to the sub-links 5 arranged on a line passing through the center of gravity G of the second lower arm 4.
Are connected via. As a result, even if the member rigidity of the vehicle-body-side connecting portion 4b of the second lower arm 4 is set low in consideration of the riding comfort, the second lower arm 4 does not
The torsional rigidity of the lower arm 4 around the link axis L2 can be set effectively high.

That is, by setting the member rigidity of the vehicle-body-side connecting portion 4b of the second lower arm 4 to be low, the high-frequency road noise is reduced and the riding comfort is avoided, and the link axis L2 of the second lower arm 4 is reduced. Since the surrounding torsional rigidity can be set high, low-frequency road noise can be reduced. Moreover, the link axis L of the sub-link 5
Since 3 passes through or near the center of gravity G of the second lower arm 4, the torsional rigidity of the second lower arm 4 around the link axis L2 can be effectively set high.

Further, the link axis L3 of the sub-link 5
Is perpendicular to, that is, perpendicular to, the link axis L2 of the second lower arm 4, so that the link axis L2 of the second lower arm 4 is
The displacement around the sub-link 5 and the displacement around the link axis L3 of the sub-link 5 are not coupled. As a result, even if the second lower arm 4 and the first lower arm 3 are connected by the sub link 5, tuning of the resonance frequency of the second lower arm 4 becomes easy,
This is an advantageous configuration for low frequency road noise performance design.

In this embodiment, each lower arm 3
By connecting the sub-link 4 to the sub-link 5 via the elastic bush 7, the assembly error of the lower arm can be absorbed by the bending of the elastic bush 7, so that the manufacture becomes easy. In addition, since the axis of each elastic bush 7 is oriented in the vertical direction, the torsional rigidity of the second lower arm 4 around the link axis L2 can be set high effectively even through the elastic bush 7, and the wheel steering is effective. The relative displacement between the first lower arm 3 and the second lower arm 4 can be absorbed by the torsional rigidity of the elastic bush 7. At this time, since the torsional rigidity of the elastic bush 7 is usually considerably lower than the torsional rigidity, a natural steering feel can be obtained as compared with the case where the axial direction of the elastic bush 7 is aligned with the other directions. Can be.

In this embodiment, since the elastic bush 7 is press-fitted into the cylindrical portion 6 (mounting portion) of the sub-link 5, the lower arms 3 and 4 have the mounting holes 9 through which the bolts 10 pass. What is necessary is just to provide as an attachment part. For this reason, even when the attachment portion to the sub link 5 is provided on the lower arms 3 and 4, the strength required for the lower arms 3 and 4 can be easily secured.

Here, in the above embodiment, the sublink 5
However, the present invention is not limited to this. The sub-link 5 may be plate-shaped, or may be curved midway. In short, a straight line passing through each connection point of the sub-link 5 with the first lower arm 3 and the second lower arm 4, that is, the link axis L3 of the sub-link 5,
The second lower arm 4 may be perpendicular or substantially perpendicular to the link axis L2, and may pass through or near the center of gravity G of the second lower arm 4. However, the center of gravity G of the sublink 5
Is preferably on the link axis L3 of the sub-link 5.

The sub-link 5 and each lower arm 3, 4
The connection with the elastic bush 7 may be made straight and connected with mounting bolts with the shaft up and down without interposing the elastic bush 7, but when the elastic bush 7 is interposed, the mounting error is reduced. This is advantageous in terms of ease of manufacturing and the like. Next, a second embodiment will be described with reference to the drawings. In addition, the first
Components and the like similar to those of the first embodiment are denoted by the same reference numerals, and the details thereof are omitted.

The basic configuration of this embodiment is the same as that of the first embodiment, except that the lower arms 3 and 4
Connection structure is different. In the second embodiment, as shown in FIG. 4, an elastic bush 7 is provided on the mounting portion side of the lower arm 3.
This is an example of press-fitting. As shown in FIG. 5, the mounting portions 21 provided at both ends of the sub link 5 each have a U-shaped cross section, and are respectively attached to a pair of plate members 21 a vertically opposed across the lower arms 3 and 4. Bolt hole 21b
Is open.

Further, a through-hole 9 whose axis is up and down is formed in a connection portion of the first lower arm 3 with the sub-link 5, and an outer cylindrical member 20 is coaxially fixed in the through-hole 9, and a lower arm is provided. Side mounting portion is configured. The elastic bush 7 is press-fitted coaxially in the outer cylinder member 20. Then, the mounting bolts 10 are penetrated in a state where the bolt holes 21b provided in the pair of plate members 21a are arranged coaxially with the outer cylinder member 20, that is, the elastic bush 7, thereby connecting the two.

Thus, each of the lower arms 3 and 4 and the sub-link 5 are connected via the elastic bush 7 whose axis is up and down. The connection structure between the second lower arm 4 and the sub-link 5 has the same configuration. Other configurations are the same as those of the first embodiment. In the present embodiment, the lower arm 3,
Since the elastic bush 7 is pressed into the mounting part on the 4 side,
Even if the axial length of each elastic bush 7 is increased, the lower arms 3 and 4
The influence on the link layout is small because the portion protruding upward and downward is small. Therefore, since the axial length of the elastic bush 7 can be made longer than in the first embodiment, the torsional rigidity of the second lower arm 4 around the link axis L2 can be further increased.

Other functions and effects are the same as those of the first embodiment. Here, the structure of the mounting portion of the sub-link 5 is not limited to the above-described configuration, and may be, for example, the same structure as in the first embodiment. Next, a third embodiment will be described with reference to the drawings. Note that the same components as those in the first embodiment are denoted by the same reference numerals, and the details are omitted.

The basic configuration of this embodiment is the same as that of each of the above embodiments, except for the connection structure of the sublink 5 to each of the lower arms 3 and 4. In the present embodiment, as shown in FIG. 6, the sub-link 5 and the first lower arm 3 employ a structure similar to that of the first embodiment or the second embodiment, and an elastic bush whose shaft is directed vertically. 7 are connected.

Further, the sub-link 5 and the second lower arm 4 are connected via a slide bearing 25 whose rotation axis is directed vertically. The sliding bearing 25 is rotatably supported only around the rotation axis. Other configurations are the same as those of the above embodiments. In the third embodiment, the connection between the first lower arm 3 and the sub-link 5 located distal from the center of gravity G of the second lower arm 4 is performed via the elastic bush 7, so that the assembly error can be reduced by the bending of the elastic bush 7. As a result, the production becomes easier. Further, since the relative displacement of the lower arms 3 and 4 due to the wheel turning can be absorbed by the elastic bush 7, a natural steering feeling can be obtained.

Further, the sliding member 25 having higher torsional rigidity as compared with the elastic bush 7 is used as a connecting member between the second lower arm 4 and the sub-link 5 near the center of gravity G of the second lower arm 4, thereby achieving the first embodiment. The torsional rigidity around the link axis L2 of the second lower arm 4 can be set higher than in the embodiment and the second embodiment. Other functions and effects are the same as those of the above embodiments.

The sliding bearing 25 may be slidable in the direction of the rotating shaft. Next, a fourth embodiment will be described with reference to the drawings. Note that the same reference numerals are given to the same components and the like as in the above embodiments, and the details are omitted. The basic configuration of this embodiment is the same as that of each of the above embodiments. However, as shown in FIG. 7, the lower arms 3 and 4 of the sub-link 5 are connected via slide bearings 25, respectively. Each sliding bearing 25 has a rotating shaft set up and down, and is capable of sliding displacement about the rotating shaft.

The sub-link 5 has a length adjusting mechanism 26 at the center in the longitudinal direction. This length adjustment mechanism 26
As a result, the sub-link 5 can be extended and contracted along the direction of the link axis L3, and the connecting portion of the sub-link 5 with the first lower arm 3 and the connecting portion with the second lower arm 4 are relatively positioned around the link axis L3. Rotational displacement is possible.

That is, the connecting portion between the lower arms 3 and 4 and the sub-link 5 is connected to the link axis L of the sub-link 5.
Along with being able to approach and separate along three directions,
Even if the lower arms 3 and 4 are connected by the sub-link 5, the length adjustment mechanism 26 allows the relative rotation displacement of the lower arms 3 and 4 about the link axis L3. In the present embodiment, since the sub-link 5 and each of the lower arms 3 and 4 are not connected via the elastic bush 7, the elastic bush 7 does not absorb an assembly error or the like. Since the length of the sub-link 5 can be extended and contracted along the link axis L3, an assembling error can be absorbed, so that the assembling property is easy, and furthermore, the relative displacement of the lower arms 3, 4 due to steering. , The natural steering feeling can be obtained.

Further, since the first lower arm 3 and the second lower arm 4 and the sub-link 5 are connected together by the slide bearing 25, the second lower arm 4 is further compared with the above-described embodiments.
The torsional rigidity around the link axis L2 can be set high. Next, a first embodiment of the length adjusting mechanism 26 will be described. In the first embodiment, a sliding structure is applied to the length adjusting mechanism 26, and the length adjusting mechanism 26 has a configuration as shown in FIG.

The length adjusting mechanism 26 is disposed coaxially from the inner diameter side and includes an inner cylinder 27, a middle cylinder 28, and an outer cylinder 29. The inner cylinder 27 forms a first slide member. Further, the middle cylinder 28 is fixed to the inner diameter surface of the outer cylinder 29 by press-fitting or the like, so that the second cylinder 28 and the outer cylinder 29
A slide member is configured. A slight gap is provided between the inner diameter surface of the middle cylinder 28 and the outer diameter surface of the inner cylinder 27, and the middle cylinder 28, the outer cylinder 29, and the inner cylinder 27 are relatively positioned around the axis. It is rotatable and relatively displaceable in the axial direction. That is, the inner cylinder 27 is relatively guided by the inner diameter surface of the middle cylinder 28 and is slidable in the direction of the link axis L3. Further, a flange portion 30 is formed at an end of the inner cylinder 27, and the flange portion 30 and the middle cylinder 2 are formed.
8 interferes with the axial end surface of the outer cylinder 2,
It is structured to prevent it from coming off from 9.

The sub-link 5 is separated into two link members 5a and 5b at the center in the longitudinal direction. The inner cylinder 27 is coaxially fixed to one of the link members 5a and the other link member. An outer cylinder 29 is coaxially fixed to 5b. Reference numeral 31 denotes a hood for preventing moisture and dust from entering. By providing the length adjusting mechanism 26, the length of the sub-link 5 expands and contracts by the inner cylinder 27 sliding relative to the outer cylinder 29 (the middle cylinder 28) in the direction of the link axis L3. That is, the distance between the connecting portions of the sub-link 5 with the lower arms 3 and 4 approaches along the link axis L3.
It is designed to leave.

In order to improve the slip between the outer diameter surface of the inner cylinder 27 and the inner diameter surface of the middle cylinder 28, a low friction material such as Teflon (registered trademark) is attached to at least one of the surfaces. Lubricating oil may be filled between the two. Next, a second embodiment of the length adjusting mechanism 26 will be described. In the second embodiment, the elastic bush 7 is applied to the length adjusting mechanism 26, and the length adjusting mechanism 26 has a configuration as shown in FIG.

The length adjusting mechanism 26 is coaxially provided with the outer cylinder 29.
And the inner cylinder 27 are arranged, and the middle cylinder 2 is
8 is press-fitted and fixed. Further, a cylindrical elastic body 32 is interposed between the inner diameter surface of the middle cylinder 28 and the inner diameter surface of the inner cylinder 27. Further, a flange portion 30 is formed at an end of the inner cylinder 27, and the flange portion 39 and the axial end surface of the middle cylinder 28 interfere with each other, so that the inner cylinder 27 is prevented from coming off from the outer cylinder 29. ing.

As a result, the inner cylinder 27 and the outer cylinder 29 (middle cylinder 28) can be relatively displaced relative to each other by a predetermined amount around the link axis L3 by the torsion of the elastic body 32, and the elastic body 32 bends. And the inner cylinder 2 with respect to the outer cylinder 29
7 can be relatively displaced in the direction of the link axis L3 by a predetermined amount. The sub-link 5 is separated into two link members 5a and 5b at the center in the longitudinal direction. The inner cylinder 27 is coaxially fixed to one of the link members 5a, and the other is externally connected to the other link member 5b. A tube 29 is fixed coaxially.

With the provision of the length adjusting mechanism 26, the length of the sub-link 5 is expanded and contracted by the inner cylinder 27 sliding axially relative to the outer cylinder 29 (middle cylinder 28). ing. Here, the length adjusting mechanism 26 is not limited to the above embodiments. For example, the sub-link 5 itself may be constituted by a cylinder device and the length adjusting mechanism 26 may be provided.

Further, in all of the above embodiments, the front suspension device in which the second lower arm 4 is disposed forward of the first lower arm 3 in the vehicle longitudinal direction is described as an example. As shown in FIG. The present invention is also applicable to a case where the second lower arm 4 is disposed rearward of the first lower arm 3 in the vehicle front-rear direction. That is, the first lower arm 3 and the second
The lower arm 4 is connected with the sub-link 5 by a sub-link 5, and the link axis L 3 of the sub-link 5 is arranged close to a straight line perpendicular to the link axis L 2 of the second lower arm 4 and passing through the center of gravity G of the second lower arm 4. .

Any of the above-described structures is adopted as the structure for connecting the sub-link 5 to each of the lower arms 3 and 4 and the structure of the sub-link 5. As a result, the same operation and effect as those of the above embodiments can be obtained.

[0056]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In this embodiment, the sublink 5 according to the present invention is used.
It was confirmed that the double pivot type suspension device connecting the two lower arms 3 and 4 at the same time as the conventional double pivot type suspension device turned the wheel 1 at the time of turning around the virtual kingpin axis. is there.

FIG. 11 shows the movement of the wheel 1, the first lower arm 3, and the second lower arm 4 during steering in the front suspension according to the first embodiment. FIG. 12 is a comparative example and shows the movements of the wheel 1, the first lower arm 3, and the second lower arm 4 when the conventional double pivot type front suspension is steered.

As can be seen from FIGS. 11 and 12,
Even if both lower arms 3 and 4 are connected by sub-link 5 by employing the front suspension device of the present invention to reduce low-frequency road noise of second lower arm 4, relative displacement of both lower arms 3 and 4 by elastic bush 7. It can be understood that the wheel 1 is rotating around the virtual kingpin axis, similarly to the conventional double pivot type front suspension. The same applies to other embodiments.

[Brief description of the drawings]

FIG. 1 is a plan view for explaining a front suspension device according to a first embodiment of the present invention.

FIG. 2 is a diagram illustrating a mounting portion of a sub-link according to the first embodiment of the present invention.

FIG. 3 is a diagram for explaining a connection structure between a first lower arm and a sub link according to the first embodiment of the present invention.

FIG. 4 is a view for explaining a connection structure between a first lower arm and a sub-link according to a second embodiment of the present invention.

FIG. 5 is a diagram illustrating a configuration of a sub-link attachment portion according to a second embodiment of the present invention.

FIG. 6 is a plan view for explaining a front suspension device according to a third embodiment of the present invention.

FIG. 7 is a plan view for explaining a front suspension device according to a fourth embodiment of the present invention.

FIG. 8 is a cross-sectional view illustrating an example of a length adjusting mechanism according to the embodiment of the present invention.

FIG. 9 is a cross-sectional view illustrating an example of a length adjusting mechanism according to the embodiment of the present invention.

FIG. 10 is a plan view for explaining a front suspension device according to an embodiment of the present invention.

FIG. 11 is a diagram showing a movement at the time of steering in the front suspension device according to the embodiment of the present invention.

FIG. 12 is a diagram showing a movement at the time of turning in a conventional front suspension device.

FIG. 13 is a plan view for explaining a conventional front suspension device.

FIG. 14 is a plan view for explaining a conventional front suspension device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Wheel 2 Wheel support member 3 1st lower arm 4 2nd lower arm 5 Sublink 6 Sublink cylindrical part (mounting part) 7 Elastic bush 9 Through hole 21 Sublink and mounting part 25 Slide bearing 26 Length adjustment mechanism 27 Inner cylinder (First slide member) 28 Middle cylinder (second slide member) 29 Outer cylinder (second slide member) 32 Elastic body P11 Wheel-side connection point of first lower arm P12 Body-side connection point of first lower arm P21 Second body of second lower arm Wheel side connection point P22 Body side connection point of second lower arm P3 Lower set point of virtual kingpin axis G Center of gravity of second lower arm G L1 Link axis of first lower arm L2 Link axis of second lower arm L3 Link axis of sub link

Claims (9)

[Claims] 1. A wheel supporting member rotatably supporting a wheel, and a vehicle body-side connecting portion is connected to the vehicle body-side member so as to be vertically swingable and extends substantially in the vehicle width direction, and the wheel-side connecting portion is connected to the wheel supporting member. A first lower arm connected to the first lower arm and a second lower arm connected to the vehicle-side member so as to be vertically swingable behind the first lower arm in the vehicle front-rear direction and to connect a wheel-side connecting portion to the wheel supporting member. The intersection of the straight line passing through the vehicle-side connection point and the wheel-side connection point of the first lower arm and the straight line passing through the vehicle-body-side connection portion and the wheel-side connection point of the second lower arm constitutes a lower set point of the virtual kingpin axis. In a front suspension device for a vehicle, a first lower arm and a second lower arm are connected by a sub-link, and a straight line passing through each connection point between the first lower arm and the second lower arm in the sub-link. The front suspension apparatus for a vehicle, characterized in that passing through the center of gravity or in the vicinity thereof of the second lower arm with are perpendicular or substantially perpendicular to a line connecting the wheel-side connecting point of the second lower arm and the vehicle body-side coupling point. 2. A wheel supporting member for rotatably supporting a wheel, and a vehicle body-side connecting portion connected to the vehicle body-side member so as to be vertically swingable and extending substantially in the vehicle width direction, and the wheel-side connecting portion is connected to the wheel supporting member. A first lower arm connected to the first lower arm, and a second lower arm connected to the vehicle body-side member so as to be vertically swingable ahead of the first lower arm in the vehicle front-rear direction and connecting a wheel-side connection portion to the wheel support member. The intersection of the straight line passing through the vehicle-side connection point and the wheel-side connection point of the first lower arm and the straight line passing through the vehicle-body-side connection portion and the wheel-side connection point of the second lower arm constitutes a lower set point of the virtual kingpin axis. In a front suspension device for a vehicle, a first lower arm and a second lower arm are connected by a sub-link, and a straight line passing through each connection point between the first lower arm and the second lower arm in the sub-link. The front suspension apparatus for a vehicle, characterized in that passing through the center of gravity or in the vicinity thereof of the second lower arm with are perpendicular or substantially perpendicular to a line connecting the wheel-side connecting point of the second lower arm and the vehicle body-side coupling point. 3. The sub-link is connected to each of a first lower arm and a second lower arm via an elastic bush, and the axis of each elastic bush is vertically oriented. The vehicle front suspension device according to claim 1 or 2. 4. The front suspension device for a vehicle according to claim 3, wherein at least one of the elastic bushes is press-fitted into a mounting portion on a lower arm side. 5. The vehicle front suspension device according to claim 3, wherein at least one of the elastic bushes is press-fitted into a mounting portion on a sub-link side. 6. The first lower arm and the sub-link are connected via an elastic bush whose shaft is oriented vertically, and the second lower arm and the sub-link are connected via a slide bearing whose rotating shaft is oriented vertically. 3. The front suspension device for a vehicle according to claim 1, wherein the front suspension device is connected to the vehicle. 7. The sub-link is connected to a first lower arm and a second lower arm via slide bearings whose rotation axes are directed vertically, and the first lower arm of the sub-link is connected to the sub-link. The front suspension device for a vehicle according to claim 1 or 2, further comprising a length adjusting mechanism capable of extending and contracting along a linear direction connecting each connecting point with the second lower arm. 8. The length adjusting mechanism includes a first slide member on the first lower arm side of the sub-link and a second slide member on the second lower arm side of the sub-link. 8. The apparatus according to claim 7, wherein the first slide member is relatively guided only by the second stud member and is relatively movable only in the expansion and contraction direction, while being arranged in the expansion and contraction direction. A front suspension device for a vehicle according to claim 1. 9. The front suspension device for a vehicle according to claim 7, wherein the length adjusting mechanism is expandable and contractable by deformation of an elastic body.