Active roll control system

An active roll control system that may be adapted to actively control roll stiffness of a vehicle by adjusting a mounting position of a stabilizer link connecting a suspension arm with a stabilizer bar of the vehicle on the suspension arm according to a driving condition of vehicle may include a driving unit which including a housing connected with a side of the suspension arm, a rail plate disposed within the housing, and a connector movable along the rail plate, and a stabilizer link of which one end may be connected with an end of the stabilizer bar and the other end may be connected with the connector through a first joint.

CROSS-REFERENCE TO RELATED APPLICATION

The present application claims priority to Korean Patent Application No. 10-2011-0132820 and 10-2011-0132868 filed in the Korean Intellectual Property Office on Dec. 12, 2011, the entire contents of which is incorporated herein for all purposes by this reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an active roll control system for a vehicle. More particularly, the present invention relates to an active roll control system (ARCS) which can actively control roll of a stabilizer bar connected to a pair of upper arms mounted respectively at both sides of a vehicle body through stabilizer links.

2. Description of Related Art

Generally, a suspension system of a vehicle connects an axle to a vehicle body so as to control vibration or impact transmitted from a road to the axle when driving not to be directly transmitted to the vehicle body. Accordingly, the suspension system of a vehicle prevents the vehicle body and freight from being damaged and improves ride comfort.

Such a suspension system, as shown inFIG. 1, includes a chassis spring101relieving impact from the road, a shock absorber103reducing free vibration of the chassis spring101and improving the ride comfort, and a stabilizer bar105suppressing roll of a vehicle (it means that a vehicle inclines with reference to a length direction of the vehicle body).

Herein, the stabilizer bar105includes a straight portion and both ends. Both sides of the straight portion are mounted at the vehicle body107, and the both ends are mounted at a lower arm109or a strut bar that is a suspension arm through the stabilizer link113. Therefore, in a case that left and right wheels111move to the same direction (upward direction or downward direction), the stabilizer bar105does not work. On the contrary, in a case that the left and right wheels111move to the opposite direction (one moves upwardly and the other moves downwardly), the stabilizer bar105is twisted and suppresses the roll of the vehicle body107by torsional restoring force.

That is, when the vehicle body107inclines toward a turning axis by the centrifugal force in a case of turning or heights of the left and right wheels is different from each other by bump or rebound of the vehicle, the stabilizer bar105is twisted and stabilizes position of the vehicle body by torsional restoring force.

Since a conventional stabilizer bar105, however, has a constant torsional rigidity, it is insufficient to secure turning stability under various driving conditions by means of torsional elastic force of the stabilizer bar105only.

Recently, an active roll control system having an actuator including a hydraulic pressure cylinder115and connected to an end of the stabilizer bar105so as to control roll actively has been developed as shown inFIG. 2.

The active roll control system uses the hydraulic pressure cylinder115instead of the stabilizer link113connecting the lower arm109and the end of the stabilizer bar105so as to change a connecting length between the end of the stabilizer bar105and the lower arm109. Therefore, torsional rigidity of the stabilizer bar105is changed.

That is, a lower end of the hydraulic pressure cylinder115is connected to the lower arm109and a front end of a piston rod117of the hydraulic pressure cylinder115is connected to the end of the stabilizer bar105through a ball joint119according to the active roll control system.

According to the active roll control system, an electronic control unit (ECU) controls a hydraulic pressure system including valves, hydraulic pressure pumps, and so on based on signals output from an acceleration sensor, a height sensor, and a steering sensor of the vehicle so as to enhance roll of the vehicle.

The lower end of the hydraulic pressure cylinder115, however, should be assembled through a separate bracket121having a lower end protruded under the lower arm109so as to secure an operation stroke of the hydraulic pressure cylinder115(i.e., actuator) to the maximum. Such a layout can be designed but productivity may be deteriorated.

Since the hydraulic pressure cylinder115is used as the actuator, components for generating and delivering hydraulic pressure (i.e., hydraulic pressure pumps, hydraulic pressure lines, valves and so on) should be necessary.

BRIEF SUMMARY

Various aspects of the present invention are directed to providing an active roll control system having advantages of actively controlling roll stiffness of a vehicle by controlling a mounting position of a stabilizer link on a suspension arm through a driving unit disposed at a side portion of the suspension arm and driven by a motor so as to change the mounting position of the stabilizer link.

According to another aspect of the present invention, an active roll control system which can be easily controlled and may have a handy layout when being mounted on a suspension arm is provided.

According to other aspect of the present invention, an active roll control system which minimize friction by applying a ball joint to a connecting portion of a stabilizer link and roller bearings to a connector so as to enhance operation efficiency.

In an aspect of the present invention, an active roll control system that is adapted to actively control roll stiffness of a vehicle by adjusting a mounting position of a stabilizer link connecting a suspension arm with a stabilizer bar of the vehicle on the suspension arm according to a driving condition of the vehicle, may include a driving unit including a housing connected with a side of the suspension arm, a rail plate disposed within the housing, and a connector slidably received in the rail plate and movable along the rail plate, and the stabilizer link of which one end is connected with an end of the stabilizer bar and the other end is pivotally connected with the connector through a first joint.

The housing is opened to upward, a side of the housing being engaged with the suspension arm, and an end of the housing being connected with a knuckle through a second joint, wherein a guide rail is formed to the rail plate, wherein the driving unit may further include a drive motor which may have a screw shaft disposed along a length direction of the rail plate, and mounted to the housing, wherein the connector is engaged with the screw shaft through a screw hole formed at a lower portion thereof within the rail plate, and is slidably supported by the rail plate through roller bearings connected thereto, and to an upper portion of which the first joint is mounted thereto, and wherein a cover is mounted on an upper portion of the housing opened upward and may include a slot corresponding an operation distance of the connector.

The suspension arm is a lower arm which is connected with a sub frame and the knuckle of the vehicle.

The first joint is a ball joint and a ball stud of the ball joint is assembled to an upper portion of the connector by press-fitting or orbital forming.

A nut housing is integrally formed to the end of the stabilizer link and is screw-engaged with the first joint.

The second joint is a ball joint.

A space is formed to a center of the rail plate and the screw shaft is disposed to the space.

The rail plate and the housing are engaged by a bolt.

An end of the screw shaft is supported by a bearing press-fitted to the housing.

The drive motor is a servo motor, rotation speed and rotating direction of which can be controlled.

The roller bearings are connected to sides of the connector as a pair.

In another aspect of the present invention, an active roll control system including a stabilizer bar adapted to actively control roll stiffness of a vehicle according to a driving condition of the vehicle, may include a suspension arm of which a penetrating slot is formed along up and down direction thereof, a driving unit including a housing mounted to an lower portion of the penetrating slot of the suspension arm, a rail plate disposed within the housing, and a connector disposed along the rail plate within the housing, the driving unit selectively moving the connector along the rail plate linearly along the rail plate, and a stabilizer link of which an upper end is connected to an end of the stabilizer bar, a lower portion of which is curved and a lower end of which is connected with the connector by a joint through the penetrating slot.

The penetrating slot is formed near an inward portion of a chassis spring support portion on the suspension arm.

A cover of which a slot corresponding to an operation distance of the connector is formed thereto is engaged to an upper portion of the penetrating slot on the suspension arm.

The housing is opened to upward, wherein a guide rail is formed to the rail plate, wherein the driving unit may further include a drive motor having a screw shaft as a rotation shaft disposed along a length direction of the rail plate and engaged with the housing, wherein the connector is engaged with the screw shaft through a screw hole formed at a lower portion thereof within the rail plate, wherein roller bearings are disposed to sides of the connector and slidably guided by the guide rails, and wherein an upper portion of the connector is connected to the lower end of the stabilizer link through a ball joint.

A ball stud of the ball joint is assembled to the upper portion of the connector by press-fitting or orbital forming.

A space is formed to a center of the rail plate and the screw shaft is disposed to the space.

An end of the screw shaft is supported by a bearing press-fitted to the housing.

The drive motor is a servo motor, rotation speed and rotating direction of which can be controlled.

The roller bearings are connected to the sides of the connector as a pair.

The suspension arm is a lower arm which is connected with a sub frame and a knuckle of the vehicle.

In an exemplary embodiment of the present invention, an active roll control system may actively control roll stiffness of a vehicle by controlling a mounting position of a stabilizer link on a suspension arm so as to turning stability of a vehicle may be enhanced.

Particularly, in turning of a vehicle, a mounting position of a stabilizer link is moved to a position at a suspension arm moving range, and thus further roll stiffness may be realized.

Also, by driving a motor, a hydraulic pressure supply system including a hydraulic pressure pump, a hydraulic pressure valve, a hydraulic pressure pipe and so on is not required for hydraulic pressure supply control, and thus layout may be enhanced.

A connector is applied with a ball joint for connecting with a stabilizer link and roller bearings for moving along a rail plate and thus friction may be reduced and operation efficiency may be enhanced.

DETAILED DESCRIPTION

Description of components that are not necessary for explaining the present invention clearly will be omitted and the first and second may be used for the same elements, however it is not limited to the order thereof.

For convenience of explaining an exemplary embodiment of the present invention, the left side will be called an outboard side and the right side will be called an inboard side inFIG. 3.

FIG. 3is a perspective view of an active roll control system according to the various exemplary embodiments of the present invention,FIG. 4is a front view of an active roll control system according to the various exemplary embodiments of the present invention, andFIG. 5is an exploded perspective view of an active roll control system according to the various exemplary embodiments of the present invention.

Referring toFIG. 3andFIG. 4, an active roll control system according to the various exemplary embodiments of the present invention includes a stabilizer bar1, a stabilizer link3and a driving unit5disposed on a lower arm7that is a suspension arm.

Herein, the stabilizer bar1includes a straight portion and both ends.

Both sides of the straight portion of the stabilizer bar1are mounted at a bracket13on the sub frame11through a mounting bushing15.

An upper end of the stabilizer link3is connected to an end of the stabilizer bar1though a ball joint BJ respectively.

The driving unit5is connected to a side of the lower arm7that is the suspension arm through a housing21, and linearly moves a connector25connected to a lower end of the stabilizer link3along a rail plate23within the housing21by operation of a motor27.

Hereinafter, referring toFIG. 5, the driving unit5will be described in detail.

The driving unit5includes the housing21, the rail plate23, the drive motor27, the connector25and a cover29.

The housing21is opened to upward and engaged with a side of the lower arm7by a bolt.

Within the housing21, guide rails35are formed to the rail plate23.

A space37is formed between the guide rails35along the length direction thereof shaped as “V”.

A lower portion of the rail plate23is engaged with the housing21by a bolt.

The drive motor27is engaged within the housing21and a rotary shaft thereof is formed as a screw shaft39, and the screw shaft39is disposed to the space23of the rail plate23penetrating the housing21.

An end of the screw shaft39is rotatably supported by a bearing B press-fitted to the housing21.

The drive motor27is a servo motor, rotation speed and rotating direction of which can be controlled.

Referring toFIG. 6, a screw hole SH is formed to a lower portion of the connector25, and roller bearings41are disposed to sides of the connector25.

The connector25is engaged with the screw shaft39through a screw hole SH within the rail plate23.

The connector25is slidably supported by the guide rails35of the rail plate23through the roller bearings41.

At this time, a pair of roller bearings41is mounted at an upper portion of the connector25and a pair of roller bearings41is mounted at a lower portion of the connector25. However, the number of the roller bearings41can be set arbitrarily.

The connector25is connected with a lower end of the stabilizer link3through a first joint J1.

The first joint J1may be a ball joint BJ1, and a ball stud of the ball joint BJ1is assembled to an upper portion of the connector25by press-fitting or orbital forming.

A nut housing43is integrally formed to an end of the stabilizer link3and is screw-engaged with a bolt portion of the first joint J1.

A slot S is formed to the cover29corresponding to operation distance of the connector25, and the cover29is engaged with the opened upper portion of the housing21.

The connector25and the stabilizer link3are connected through the slot S of the cover29, and the cover29and the housing21are engaged by a bolt.

The active roll control system controls the mounting position of the stabilizer link3on the lower arm7according to driving condition of a vehicle by driving the drive motor27of the driving unit5mounted to the side of the lower arm7.

Since the mounting position of the stabilizer link3is changed, the roll stiffness of a vehicle due to the stabilizer bar1may be enhanced. That is, resistance characteristic against roll of a vehicle may be enhanced and thus turning stability may be improved.

A protruded portion33is formed to an end of the housing21and is connected to a lower portion of a knuckle17through a second joint J2. The second joint J2may be a ball joint BJ2.

Referring toFIG. 7, operations of the active roll control system according to the various exemplary embodiments of the present invention will be described.

In a case that the vehicle runs straight, the connector25determining the mounting position of the stabilizer link3on the lower arm7is positioned at an initial position P1as shown inFIG. 7.

If the vehicle turns at this state, a controller controls the drive motor27to rotate in one direction based on signals output from an acceleration sensor, a height sensor, and a steering sensor.

Then, the connector25on the screw shaft39moves to “P2” inFIG. 7, the connector25determining the mounting position of stabilizer link3on the lower arm7is positioned at P2, and thus a total roll stiffness of a vehicle due to the stabilizer bar1is enhanced. That is, since resistance characteristic against the roll is increased and thus turning stability of the vehicle may be enhanced.

As described above, in an exemplary embodiment of the present invention, the active roll control system may actively adjust the mounting position of the stabilizer link3on the lower arm7by driving the drive motor27according to the driving condition of a vehicle, and thus the roll stiffness of a vehicle may be enhanced.

When the vehicle turns, the mounting position of the stabilizer link3on the lower arm7is changed, and thus the more resistance characteristic against the roll may suppress the roll of the vehicle body actively.

Also, by driving the motor27, a hydraulic pressure supply system including a hydraulic pressure pump, a hydraulic pressure valve, a hydraulic pressure pipe and so on is not required for hydraulic pressure supply control, and thus layout may be enhanced.

The connector25is applied with the ball joint BJ1for connecting with the stabilizer link3and the roller bearings41for moving along the rail plate23and thus friction may be reduced and operation efficiency may be enhanced.

FIG. 8is a perspective view of an active roll control system according to the various exemplary embodiments of the present invention,FIG. 9is a front view of an active roll control system according to the various exemplary embodiments of the present invention, andFIG. 10is an exploded perspective view of an active roll control system according to the various exemplary embodiments of the present invention.

Referring toFIG. 8toFIG. 10, an active roll control system according to the various exemplary embodiments of the present invention includes a stabilizer bar201, a stabilizer link203and a driving unit205disposed on a lower arm207that is a suspension arm.

Herein, the stabilizer bar201includes a straight portion and both ends.

Both sides of the straight portion of the stabilizer bar201are mounted at a bracket213on the sub frame211through a mounting bushing215.

An upper end of the stabilizer link203is connected to an end of the stabilizer bar201though a ball joint BJ respectively.

An outward end of the lower arm207is connected to a lower portion of a knuckle217through a protruded portion233, and a penetrating slot209is formed up and down direction of the lower arm207. The penetrating slot209is positioned near an inward portion of a chassis spring support portion F on the lower arm207.

The driving unit205is mounted to a lower portion of the penetrating slot209of the lower arm207through a housing221, and linearly moves a connector225connected to a lower end of the stabilizer link203along a rail plate223within the housing221by operation of a motor227.

Hereinafter, referring toFIG. 10, the driving unit205will be described in detail.

The driving unit205includes the housing221, the rail plate223, the drive motor227and the connector225.

The housing221is opened to upward and engaged with a lower portion near the penetrating slot209by a bolt.

Guide rails235shaped as a pocket is formed to the rail plate223within the housing221.

A space237is formed between the guide rails235along the length direction thereof shaped as “V”.

A lower portion of the rail plate223is engaged with the housing221by a bolt.

The drive motor227is engaged within the housing221and a rotary shaft thereof is formed as a screw shaft239, and the screw shaft239is disposed to the space223of the rail plate223penetrating the housing221.

An end of the screw shaft239is rotatably supported by a bearing B press-fitted to the housing221.

The drive motor227is a servo motor, rotation speed and rotating direction of which can be controlled.

A screw hole SH is formed to a lower portion of the connector225, and roller bearings241are disposed to sides of the connector225.

The connector225is engaged with the screw shaft239through a screw hole SH within the rail plate223.

The connector225is slidably supported by the guide rails235of the rail plate223through the roller bearings241.

At this time, a pair of roller bearings241is mounted at an upper portion of the connector225and a pair of roller bearings241is mounted at a lower portion of the connector225. However, the number of the roller bearings241can be set arbitrarily.

The connector225is connected with a lower end of the stabilizer link203through a ball joint BJ.

An upper end of a stabilizer link203is connected to an end of the stabilizer bar201through a ball joint BJ, a lower portion of the stabilizer link203is curved and a lower end of the stabilizer link203is inclined connected with the connector225by a ball joint BJ through the penetrating slot209.

A ball stud BS of the ball joint BJ is assembled to an upper portion of the connector225by press-fitting or orbital forming beforehand.

A cover229of which a slot S corresponding to an operation distance of the connector225is formed thereto is engaged to an upper portion of the penetrating slot209on the lower arm207.

The connector225and the stabilizer link203are connected through the slot S of the cover229, and the cover229and the housing221are engaged by a bolt.

The active roll control system controls the mounting position of the stabilizer link203on the lower arm207according to driving condition of a vehicle by driving the drive motor227of the driving unit205mounted to the side of the lower arm207.

Since the mounting position of the stabilizer link203is changed, the roll stiffness of a vehicle due to the stabilizer bar201may be enhanced.

Referring toFIG. 11, operations of the active roll control system according to the various exemplary embodiments of the present invention will be described.

In a case that the vehicle runs straight, the connector225determining the mounting position of the stabilizer link203on the lower arm207is positioned at an initial position P1as shown inFIG. 11.

If the vehicle turns at this state, a controller controls the drive motor227to rotate in one direction based on signals output from an acceleration sensor, a height sensor, and a steering sensor.

Then, the connector225on the screw shaft239moves to “P2” inFIG. 11, the connector225determining the mounting position of stabilizer link203on the lower arm207is positioned at P2, and thus a total roll stiffness of a vehicle due to the stabilizer bar201is enhanced. That is, since resistance characteristic against the roll is increased and thus turning stability of the vehicle may be enhanced.

As described above, in an exemplary embodiment of the present invention, the active roll control system may actively adjust the mounting position of the stabilizer link203on the lower arm207by driving the drive motor227according to the driving condition of a vehicle, and thus the roll stiffness of a vehicle may be enhanced.

When the vehicle turns, the mounting position of the stabilizer link203on the lower arm207is changed, and thus the more resistance characteristic against the roll may suppress the roll of the vehicle body actively.

Also, by driving the motor227, a hydraulic pressure supply system including a hydraulic pressure pump, a hydraulic pressure valve, a hydraulic pressure pipe and so on is not required for hydraulic pressure supply control, and thus layout may be enhanced.

Also, the stabilizer link203is curved, and thus a lower portion of the chassis spring support portion F may be utilized for the operation distance of the connector225so that the roll stiffness due to the stabilizer link203may be enhanced.

The connector225is applied with the ball joint BJ for connecting with the stabilizer link203and the roller bearings241for moving along the rail plate223and thus friction may be reduced and operation efficiency may be enhanced.