Active roll control system

An active roll control device utilizes a driving torque to move a suspension arm side connection point of a stabilizer link that connects both sides of a stabilizer bar with a suspension arm along a sliding unit such that roll of a vehicle is actively controlled. The sliding unit includes a linear shaft that extends in a vehicle width direction in a housing on the suspension arm, a linear bushing into which the linear shaft is inserted to be slidably moved along the linear shaft in the housing, and a bushing housing that is fixed on an external circumference of the linear bushing, a double ball joint is fixed on an inner side thereof to connect the bushing housing, and the double ball joint is connected to a drive shaft of the drive source through one end of a push rod and a lower end of the stabilizer link.

CROSS-REFERENCE TO RELATED APPLICATION

The present application claims priority of Korean Patent Application Number 10-2011-0132274 filed Dec. 9, 2011, the entire contents of which application is incorporated herein for all purposes by this reference.

BACKGROUND OF INVENTION

1. Field of Invention

The present invention relates to an active roll control device of a vehicle. More particularly, the present invention relates to an active roll control device (ARCS: Active Roll Control System) that actively controls roll with a stabilizer bar that is disposed at both suspension arms through a stabilizer link.

2. Description of Related Art

Generally, a suspension system of a vehicle connects an axle with a vehicle body, and prevents vibration or impact that is transferred from the road from being transferred to the vehicle body while driving to enhance ride comfort.

The suspension system includes a chassis spring that reduces impact transferred from the road, a shock absorber that dampens free vibration of the chassis spring to improve ride comfort, and a stabilizer bar that reduces roll of a vehicle.

The stabilizer bar is fixed on a vehicle body and both end portions thereof are respectively fixed to a lower arm or a strut bar through a stabilizer link.

Accordingly, the stabilizer bar is not operated while left and right wheels are equally moved up/down and reduces roll of a vehicle body through a torsion elastic force while the left and right wheels are differently moved up/down.

FIG. 1is a partial perspective view of a suspension system for a vehicle that uses an active roll control device according to a conventional art.

Referring toFIG. 1, an active roll control device of a conventional art improves a roll characteristic of a vehicle by varying rigidity of a stabilizer bar1according to a driving condition of a vehicle.

The active roll control device includes a stabilizer bar1, a stabilizer link3, a sliding unit5that is disposed on a lower arm7as a suspension arm, and a drive source6.

The stabilizer bar1is mounted on a bracket13of a sub-frame11at a vehicle body side through a mounting bushing15.

Also, one end of the stabilizer link3is connected to one end of the stabilizer bar1through a ball joint (BJ).

Meanwhile, an outer end portion of the lower arm7is connected to a lower side of a knuckle17and includes a housing portion21to form the sliding unit5.

The sliding unit5includes a slide rail23at both sides of the inside of the housing portion21on the lower arm7in a vehicle width direction, and a connector25that is connected to a lower end of the stabilizer link3is disposed between the slide rail23to be guided in a vehicle width direction.

The drive source6includes a motor19having a drive shaft27that is operated in both directions and is disposed at one side of the sub-frame11, and the drive shaft27is connected to the connector25through a push rod29to draw or push the connector25.

The conventional active roll control device that is configured as described above adjusts a connection position of the stabilizer link3on the lower arm7through the operation of the motor19according to the driving condition of the vehicle, and actively controls the lever ratio of the stabilizer link3to adjust the roll rigidity and the turning stability of the vehicle.

Meanwhile, because the above active roll control device is disposed in a narrow space that is formed at a lower portion of a vehicle body, the system has to be compact, but frictional resistance of the sliding unit is a factor that deteriorates the size reduction of the drive source6.

For this, recently there has been a demand for minimizing the frictional resistance between the connector25and the slide rail23of the sliding unit5such that power delivery efficiency of the motor19as a drive source is improved to enable the size reduction.

SUMMARY OF INVENTION

Various aspects of the present invention provide for an active roll control device having advantages of connecting a bushing housing having a linear bushing that slides along both side linear shafts to a stabilizer link and a push rod through a double ball joint and absorbing a vertical load that is applied to the sliding unit and moment loads that are transferred from various directions to minimize frictional resistance.

Various aspects of the present invention provide for an active roll control device that uses a driving torque that is transferred from a drive source to move a suspension arm side connection point of a stabilizer link that connects both sides of a stabilizer bar with a suspension arm along a sliding unit such that roll of a vehicle is actively controlled, wherein the sliding unit includes a linear shaft that is disposed in parallel at both sides along a vehicle width direction in a housing portion that is formed on the suspension arm, a linear bushing into which the linear shaft is inserted to be slidably moved along the linear shaft in the housing portion, and a bushing housing that is fixed on an external circumference of the linear bushing, a double ball joint is fixed on an inner side thereof to connect the bushing housing, and the double ball joint is connected to a drive shaft of the drive source through one end of a push rod and a lower end of the stabilizer link.

Both end portions of the linear shaft may be respectively fixed on a rear/front side of the inside of the housing through a fixed bracket.

A dust cover may cover the linear shaft, one end of the dust cover is connected to the fixed bracket, and the other end thereof is connected to the bushing housing.

The bushing housing may include a socket groove that is formed between both linear shafts, and both ends of a center shaft of the double ball joint are inserted into the socket groove to be fixed thereto.

The bushing housing may have a linear bushing that slides along both side linear shafts adjusts a connection position of the stabilizer link on the suspension arm by using the driving torque of the motor inside the housing portion of the suspension arm according to the driving conditions of the vehicle such that the roll rigidity of the vehicle is actively controlled to improve the turning stability of the vehicle.

Also, the linear bushing slides along both side linear shaft of the sliding portion such that the sliding unit absorbs the vertical load that is applied thereto and the moment loads of various directions to minimize the frictional resistance.

Thereby, the power delivery efficiency of the motor is improved to be able to reduce the size of the system.

DETAILED DESCRIPTION

FIG. 2is a perspective view of a lower arm that is assembled to a sliding unit that is applied to an active roll control device according to various embodiments of the present invention,FIG. 3is an exploded perspective view of a sliding unit that is applied to an active roll control device according to various embodiments of the present invention, andFIG. 4is a cross-sectional view of a sliding unit that is applied to an active roll control device according to various embodiments of the present invention.

Referring toFIG. 2toFIG. 4, an active roll control device according to various embodiments of the present invention varies a rigidity value of the stabilizer bar1depending on the driving conditions of the vehicle to actively improve the roll of the vehicle.

As shown inFIG. 1, the active roll control device basically includes the stabilizer bar1, a stabilizer link3, a sliding unit5that is formed on a lower arm7that is a suspension arm, and a drive source6.

Both sides of the stabilizer bar1are disposed on a bracket13of a sub-frame11at a vehicle body side through a mounting bushing15.

And, an upper end of the stabilizer link3is connected to one end of the stabilizer bar1through a ball joint (BJ).

Meanwhile, an outside end portion of the lower arm7is connected to a lower side of the knuckle17and forms a housing portion21at one side thereof to house the sliding unit5.

Referring toFIGS. 2 and 3, the sliding unit5includes a linear shaft23that is disposed at both sides of the inside of the housing portion21on the lower arm7and a bushing housing25is respectively disposed on the linear shaft23to be connected to a lower end of the stabilizer link3, wherein the bushing housing25is guided in a vehicle width direction along the linear shaft23.

Also, the drive source6includes a motor19that has a drive shaft27that is moved forward/reward to be disposed at one side of the sub-frame11, and the drive shaft27is connected to both sides bushing housing25through the push rod29and pushes or draws the bushing housing25.

Accordingly, the active roll control device having such a structure as described above adjusts a connection position of the stabilizer link3on the lower arm7through the operation of the motor19depending on the driving conditions of the vehicle to vary the lever ratio of the stabilizer link3such that the roll rigidity of the vehicle is actively controlled to improve the turning stability of the vehicle.

Meanwhile, such active roll control device is disposed in a narrow space that is formed at a lower portion of the vehicle body and therefore has to have a compact structure, and for this, frictional resistance of the sliding unit5is minimized to enhance the power delivery efficiency of the motor19in various embodiments of the present invention such that the drive source6is reduced in size.

Hereinafter, referring toFIG. 3andFIG. 4, the configuration of the sliding unit5will be described.

As shown, the sliding unit5includes the linear shaft23, the bushing housing25, and a linear bushing31.

Two linear shafts23are disposed in parallel at both sides along a vehicle width direction inside the housing portion21, and both ends of the linear shafts23are inserted into the fixed bracket24that is fixed on a rear/front inner surface of the inside of the housing portion21to be fixed.

In this configuration, the linear bushing31is slidably disposed on the linear shaft23along an axial direction.

Also, the linear bushing31that is disposed on the linear shaft23is forcibly inserted into an interior circumference of the bushing housing25and is disposed to be moved along the linear shaft23together with the linear bushing31.

The bushing housing25has a socket groove43that is formed therebetween.

That is, both ends of the center shaft41of a double ball joint2BJ that is connected to the push rod29of the drive shaft27of the motor19and to the stabilizer link3are respectively inserted into the socket groove43such that the bushing housing25is simultaneously connected to the push rod29and the stabilizer link3.

A dust cover26that is flexibly transformed covers the linear shaft23to prevent foreign materials from entering.

That is, a dust cover26is disposed at both sides across the bushing housing25on the linear shaft23and both ends thereof are fixed on the bushing housing25and the fixed bracket24.

In this configuration, the dust cover26is folded in a short stroke or unfolded in a long stroke depending on the position of the bushing housing25on the linear shaft23.

Accordingly, the sliding unit5having such a structure as described above absorbs a vertical load and moment load of various directions that are transferred between the linear shaft23and the linear bushing31and also enables the linear bushing32to be slid on the linear shaft23while the vehicle variously moves, particularly in a bump or rebound condition, such that the power delivery efficiency of the motor19is enhanced.

That is, while a vertical load is generated in the bump or rebound condition of the vehicle, a circularly distributed load that is formed between the linear shaft23and the linear bushing31minimizes the frictional resistance of the sliding.

For convenience in explanation and accurate definition in the appended claims, the terms upper or lower, front or rear, inside or outside, and etc. are used to describe features of the exemplary embodiments with reference to the positions of such features as displayed in the figures.