Abstract: A stabilizer control apparatus includes a first torsion bar, a second torsion bar, and a connecting and disconnecting means including a rotation member rotating as a unit with the first torsion bar, and a housing accommodating therein the rotation member so as to be rotatable and forming two pressure chambers, the two pressure chambers being filled with a fluid. The connecting and disconnecting means generates a connecting state in which a movement of the fluid to the two pressure chambers is blocked so that a relative rotation between the first torsion bar and the second torsion bar is prohibited and a disconnecting state in which a movement of the fluid to the two pressure chambers is allowed so that the relative rotation between the first torsion bar and the second torsion bar is allowed.

Abstract: A stabilizer bar for controlling the roll of an automotive vehicle has left and right sections, each provided with a torsion rod and a torque arm. The torsion rods are aligned along a transverse axis and attached to a structural component of the vehicle, while the torque arms are connected to the left and right control arms of the vehicle's suspension system. In addition, the bar has a coupling between the torsion rods of the two sections for controlling the torsional stiffness of the bar. The coupling includes a rotor fitted to one of the torsion rods and a housing fitted to the other torsion rod, with the housing receiving the rotor, such that a cavities exist between the rotor and housing. Both the rotor and housing carry vanes, that alternate so that the vanes of the rotor are located between the vanes of the housing. The cavities contain a magneto-rheological fluid.

Abstract: A connection of the stabilizer parts of a two-part stabilizer to an actuator is usually performed in a positive-locking manner, as a result of which an additional axial securing and hydraulic sealing toward the outside become necessary. To simplify the design and the manufacturing process, it is provided that the teeth between the outer rotary part (4) and the second stabilizer part (2) be made clearance-free and welded together by a circumferential weld seam (18), wherein the seam area is preheated to a temperature of 350° C. and subsequently cooled to a martensite content of 30% in the microstructure.

Abstract: A stabilizer control apparatus for controlling a torsional rigidity of a stabilizer arranged between a right wheel and a left wheel of a vehicle includes a turning state detecting device for detecting a turning state quantity of the vehicle, and a switching device for switching the torsional rigidity of the stabilizer and including a first position in which a first torsional rigidity is achieved and a second position in which a lower torsional rigidity than the first torsional rigidity is achieved. The switching device switches between the first position and the second position based on the turning state quantity detected by the turning state detecting device. Further, the switching device switching the first position to the second position when a state in which the turning state quantity detected by the turning state detecting device is equal to or smaller than a predetermined value continues for a predetermined time or more.

Abstract: It is a purpose in a divided stabilizer to increase the springy lengths of the two stabilizer components. The stabilizer components (1, 1?, 2, 2?) have respective rotary parts (4, 4?, 5, 5?) attached and the rotary parts in turn have respective rotary wings (14, 16) attached. A cover flange (8?) is formed at the outer rotary part (4?). An outer rotary wing (14) is radially inwardly directed and attached to the outer rotary part (4?). An inner rotary wing (16) is radially outwardly directed and is attached to the inner rotary part (5?). A second stabilizer part (2, 2?) is attached to the inner rotary part (5?), wherein the outer rotary part (4?) with the outer rotary wing (14) moves relative to the liner rotary part (5?) with the inner rotary wing (16) up to the point where the outer rotary wing (14) contacts the inner rotary wing (16). The rotary wings (14, 16) are rotatable relative to each other up to a predetermined angle. The stabilizer is coordinated in parallel to an axle of a vehicle.

Abstract: Coupling mechanism for a vehicle anti-roll bar comprising a first piece able to be fixed to a first half-bar, a second piece able to be fixed to a second half-bar, the second piece being so arranged as to be moveable in rotation about an axis of rotation A relative to the first piece. The mechanism includes at least one elastically deformable elongate element coupled to the first and second pieces so that relative rotation of the first and second pieces about the axis of rotation A causes elastic flexion deformation of the at least one elongate element, the mechanism including an actuator able to position the at least one elongate element in a first state in which the said at least one elongate element presents a first flexion stiffness for the said elastic flexion deformation, and a second state in which the said at least one elongate element presents a second flexion stiffness for the said elastic flexion deformation.

Abstract: A stabilizer control apparatus operating to contort stabilizer bars ensures the stability of a vehicle, even in the event that one of the front and rear stabilizer bars of the vehicle is stuck in a contorted state.

Abstract: A roll bar (1?) for a motor vehicle is proposed according to the present invention, with an unsplit torsion bar (5?), which is rotatably fastened to a vehicle chassis (3), is connected to two opposite wheel suspensions (4?) of the said axle of the vehicle, and has a torsion area for the elastic coupling of spring action movements of the opposite wheel suspensions (4?), wherein the roll bar (1?) has, furthermore, a first torsion tube (8?), which surrounds the unsplit torsion bar (5?) at least in a first partial area (B?) of its torsion area, and whose first end (8a?) is connected to the unsplit torsion bar (5?), rotating in unison therewith, and whose second end (8b?) can be connected to the unsplit torsion bar (5?) by means of a clutch arrangement (9?) in such a way that it selectively rotates in unison therewith, so that the torsional stiffness of the roll bar (1?) can be varied.

Abstract: Roll stabilizer for the chassis of a motor vehicle having an actuator (3) arranged between stabilizer halves (1, 2) and rotating them relative to one another around a rotational axis, when necessary. The actuator (3) is provided with a failsafe device (34), which connects the two stabilizer halves (1, 2) in a torque proof manner, when necessary.

Abstract: A decoupled anti-roll system comprising a left anti-roll bar fastened at one end to a left suspension arm, a right anti-roll bar fastened at one end to a right suspension arm, a clutch mounted to connect or separate the left and right anti-roll bars, oil pressure generating apparatus configured to generate oil pressure during a vehicle roll, an accumulator connected to the oil pressure generating apparatus, and actuators for activating the clutch via the oil pressure generated from the oil pressure generating apparatus to connect or separate the left and right anti-roll bars, whereby the left and right anti-roll bars are connected to each other only when a vehicle rolls, thus improving a car's ride and steering.

Abstract: In a suspension system (20) for use in a vehicle including a body, left and right front wheels (10), and left and right rear wheels (12), a front-wheel-associated cylinder device (52) which controls a relative displacement of the left and right front wheels, and a rear-wheel-associated cylinder device (62) which controls a relative displacement of the left and right rear wheels are associated with each other with a working fluid. A first-chamber-associated valve (190) is provided in a first-chamber-associated passage (90) which connects between respective first chambers (74) of the front-wheel-associated cylinder device and the rear-wheel-associated cylinder device, such that the first-chamber-associated valve is located between the first chamber of the front-wheel-associated cylinder device and a first fluid accommodating device (200).

Abstract: A roll control system for a motor vehicle comprising a torsion bar (16); a first hydraulic actuator (12) connected to one end (20) of the torsion bar and connectable to an axle (34) of the vehicle; a second hydraulic actuator (14) connected to the other end (28) of the torsion bar and connectable to the axle of the vehicle; a hydraulic control system (62) connected to the hydraulic actuators and including a source of fluid pressure (66), a fluid reservoir (68), at least one supply valve (74, 76), and a pressure control valve (70); and an electrical control system (64) controlling the hydraulic system dependent on sensed vehicle conditions; wherein each hydraulic actuator comprises a rebound chamber (42, 52) and a compression chamber (40, 50) separated by a piston (38, 48), and a piston rod (18, 26) attached to the piston and extending through and out of the rebound chamber; wherein, during straight line motion of the vehicle, the electrical control system actuates the supply valve or valves to isolate the reb

Abstract: An active roll control system includes a stabilizer bar, a stabilizer link having a screw gear formed therein, a rack movably connected to the outside of the stabilizer link, and an electric motor connected to the stabilizer link. The rack has a mating screw gear formed in the inner surface thereof to correspond to a screw gear of the stabilizer link.

Abstract: An apparatus for controlling stiffness of an anti-roll bar for a vehicle, comprising: An apparatus for controlling stiffness of an anti-roll bar for a vehicle includes an anti-roll bar provided with piezoelectric ceramics, the anti-roll bar interconnecting both lower arms of a vehicle suspension system, a power converter connected to a power supply to change an amount of electric power and to supply the electric power to the piezoelectric ceramics of the anti-roll bar, and a controller connected to the power converter to calculate an amount of the electric power needed for providing the piezoelectric ceramics with optimal stiffness based on previously stored vehicle speed and steering angle in response to data detected by a vehicle speed sensor and a steering angle sensor and to control the power converter such that the calculated electric power can be supplied to the piezoelectric ceramics.

Abstract: The invention relates to a stabilizer for a motor vehicle. Known one-piece stabilizers are designed either solely for operation in road traffic or solely for off-road operation. Two-piece stabilizers that comprise an engaging and disengaging clutch have disadvantages regarding quality and safety. The invention provides a clutch, drivers (14, 17) of which form at least two adjustable gaps in the peripheral direction. The gaps can be filled by at least two locking elements (25) that can be displaced to a certain extent. The locking elements (25) and said drivers (14, 17) are constantly in positive engagement with one another in the peripheral direction and are adjusted to one another in such a manner that the locking elements (25) and the drivers (14, 17) are interlocked without play in the locked final position and that they can be rotated towards one another across a limited angle in the unlocked final position.

Abstract: Roll stabilizer for the chassis of a motor vehicle having an actuator (3) arranged between stabilizer halves (1, 2) and rotating them relative to one another around a rotational axis, when necessary. The actuator (3) is provided with a failsafe device (34), which connects the two stabilizer halves (1, 2) in a torque proof manner, when necessary.

Abstract: In a stabilizer control apparatus for a vehicle, a stabilizer includes a pair of stabilizer bars disposed between a right wheel and a left wheel of the vehicle, and an actuator having an electric motor and a speed reducing mechanism disposed between the stabilizer bars. A desired torque for the electric motor is calculated on the basis of a vehicle behavior and a steering operation of a vehicle driver, and estimated is a torsional torque created on each end portion of each of the stabilizer bars mounted on the vehicle. According to a feedback controller, the electric motor is controlled in response to the result compared between the desired torque and the estimated torsional torque.

Abstract: An adjustable stabilizer bar assembly is disclosed. The adjustable stabilizer bar assembly includes a cylindrical housing; a first primary half bar, having an inner end and an outer end, wherein the inner end of the first primary half bar is mounted to the cylindrical housing and the outer end of the first primary half bar is mounted to a vehicle suspension; a splined cylindrical housing; a second primary half bar, having an inner end and an outer end, wherein the inner end of the second primary half bar is mounted to the splined cylindrical housing and the outer end of the second primary half bar is mounted to the vehicle suspension; a splined torsion bar, adjustably disposed between the cylindrical housing and the splined cylindrical housing; and a slidable assembly, disposed about the second primary half bar, wherein the slidable assembly can slide back and forth along the second primary half bar to uncover a portion of the splined torsion bar.

Abstract: A stabilizer for a motor vehicle has a torsion bar divided into two shafts (1 and 2). The two shafts (1 and 2) are connected to one another via a mechanical coupling. The coupling has a locking disk, which is connected to a first of the two shafts (1), rotating with it in unison, and on the circumference of which at least one locking area is formed, and a housing (3), which is connected to the second shaft (2), rotating with it in unison. At least one locking mechanism (10), which is complementary to the locking area and engages the locking area in the coupled state of the coupling, is mounted movably on the housing (3). Furthermore, a spring (11), by which the locking mechanism (10) is pretensioned in the direction of the locking disk, is connected to the housing (3) and to the locking mechanism (10).

Abstract: The piston 10 is constituted so as to rotate relative to the first cylinder 8 while moving relative to the first cylinder 8 in the axial direction when fluid is supplied to and discharged from the interior of the first cylinder 8, and the piston 16 is constituted to be incapable of rotation relative to the second cylinder 9, but capable of movement relative to the second cylinder 9 in the axial direction. Hence when fluid is supplied to and discharged from the interior of the first cylinder 8, the piston 10 is caused to rotate relative to the first cylinder 8 while moving relative to the first cylinder 8 in the axial direction, and the piston 16 is caused to move relative to the second cylinder 9 in the axial direction but prevented from rotating relative to the second cylinder 9. As a result, torsional elasticity is generated in shaft portions 4a and 5a.

Abstract: An adaptive suspension system for a motor vehicle varies suspension parameters in response to steering input. The system includes a sensor to measure changes in the power assist steering mechanism that indicate a change in vehicle direction and a shock variable suspension member changed in response to a change in vehicle direction. The sensor measures pressure changes in the power assist steering system such that the suspension system is optimized to accommodate specific vehicle maneuvering. In another embodiment, the variable suspension member is in hydraulic communication with the hydraulic circuit of the power assist steering mechanism such that pressure changes caused by steering input triggers changes in the suspension system to accommodate vehicle maneuvering.

Abstract: A drive unit is provided for the coaxial twisting movement of two stabilizer halves (1, 3) of a motor vehicle axle stabilizer with a tubular housing.

Abstract: A stabilizer arrangement for a motor vehicle has a torsion bar with two bar parts with first ends which can each be connected with a wheel suspension of a wheel axle having two wheels. The stabilizer arrangement, in addition, has a clutch with first and second clutch elements. The clutch form-lockingly connects or separates two second ends of the bar parts situated adjacent to one another. For a form-locking connection, each clutch element has at least two form closure elements. When the clutch is separated, each clutch element can be rotated relative to the other. The stabilizer arrangement also has an operating device for the separation of the clutch. In order to simplify the operating device of the clutch, the form closure elements of the first or second clutch element form engaging elements movably linked thereto. For a separation of the clutch, the engaging elements are movable independently of one another. The elements are displaceable independently of one another by the operating device.

Abstract: Stabilizer for a motor vehicle with a torsion bar divided into two shafts 1 and 2, wherein the two shafts 1 and 2 are connected to one another via a mechanical coupling. The coupling has a locking disk, which is connected to a first of the two shafts 1, rotating with it in unison, and on the circumference of which at least one locking area is formed, and a housing 3, which is connected to the second shaft 2, rotating with it in unison. At least one locking means 10, which is complementary to the locking area and engages the locking area in the coupled state of the coupling, is mounted movably on the housing 3. Furthermore, a spring 11, by which the locking means 10 is pretensioned in the direction of the locking disk, is connected to the housing 3 and to the locking means 10.

Abstract: A suspension system for a vehicle. A control arm is attachable to the vehicle frame by a first bushing and by a second bushing and is attachable to the knuckle by a ball joint. A torsion spring assembly has a torsion tube and a torsion bar positioned within the torsion tube. A first end portion of the torsion bar is attached to a first end portion of the torsion tube, and a second end portion of the torsion bar extends beyond a second end of the torsion tube and is attached to the control arm. No portion of the torsion tube is immobilized with respect to the frame. A moment bar has a first end portion attached to the torsion tube and has a second end portion attachable to the frame.

Abstract: An adjustable stabilizer bar (10) for a vehicle comprises a primary torsional reaction segment (12). The primary reaction segment includes an outer tube (36) selectively engaged through a splined cog (58) to a torsional bar (42). The cog (58) can be positioned to provide zero torsional stiffness by decoupling the outer tube (36) from the torsional bar (42) and it can be positioned to vary the torsional stiffness between minimum and maximum torsional stiffness positions wherein the cog engages the outer tube (36) to the torsional bar (42).

Abstract: A housing attaches a stabilizer bar to the body of a vehicle and includes pin stops which actively control the stiffness of the stabilizer bar. A spring positioned about each of the pins provide a retaining spring force on the head of the pin, preventing the pins from moving into an aperture in the housing. When a sensor detects that lateral acceleration or yaw rate exceeds a threshold value, an actuator drives pins to overcome the spring force, pushing the pins into the aperture. When the pins are actuated, a protrusion on the stabilizer bar is trapped between the pins. When the vehicle turns and the stabilizer bar axially twists, the protrusion eventually contacts one the pins, preventing further rotation and stiffening the stabilizer bar.

Abstract: An adaptive suspension system for a motor vehicle varies suspension parameters in response to steering input. The system includes a sensor to measure changes in the power assist steering mechanism that indicate a change in vehicle direction and a shock variable suspension member changed in response to a change in vehicle direction. The sensor measures pressure changes in the power assist steering system such that the suspension system is optimized to accommodate specific vehicle maneuvering. In another embodiment, the variable suspension member is in hydraulic communication with the hydraulic circuit of the power assist steering mechanism such that pressure changes caused by steering input triggers changes in the suspension system to accommodate vehicle maneuvering.

Abstract: Improvements for a vehicle stabilizer bar assembly having a pair of stabilizer bar members that are selectively uncoupled via a clutch assembly to provide a vehicle with improved traction. A first improvement concerns a reserve powering apparatus for powering the clutch assembly in the event of an electrical failure that prevents the vehicle power source from transmitting electrical power to the clutch assembly. A second improvement concerns a speed sensing apparatus for inhibiting the operation of the stabilizer bar assembly in a disengaged condition if the speed of the vehicle is greater than or equal to a predetermined speed threshold. A third improvement concerns a logic for controlling the engagement and disengagement of a pair of stabilizer bar assemblies.

Abstract: An adjustable stabilizer bar (10) for a vehicle comprises a primary torsional reaction segment (12). The primary reaction segment includes an outer tube (36) selectively engaged through a splined cog (58) to a torsional bar (42). The cog (58) can be positioned to provide zero torsional stiffness by decoupling the outer tube (36) from the torsional bar (42) and it can be positioned to vary the torsional stiffness between minimum and maximum torsional stiffness positions wherein the cog engages the outer tube (36) to the torsional bar (42).

Abstract: A housing attaches a stabilizer bar to the body of a vehicle and includes pin stops which actively control the stiffness of the stabilizer bar. A spring positioned about each of the pins provide a retaining spring force on the head of the pin, preventing the pins from moving into an aperture in the housing. When a sensor detects that lateral acceleration or yaw rate exceeds a threshold value, an actuator drives pins to overcome the spring force, pushing the pins into the aperture. When the pins are actuated, a protrusion on the stabilizer bar is trapped between the pins. When the vehicle turns and the stabilizer bar axially twists, the protrusion eventually contacts one the pins, preventing further rotation and stiffening the stabilizer bar.

Abstract: An assembly for use as part of a vehicle suspension system includes an adjustable roll rate that is automatically adjusted responsive to maneuvers of the vehicle. A stiffener element is coupled with a stabilizer bar. The stiffener element increases the roll rate responsive to the vehicle wheels being turned. In one example, the stiffener element is a metallic plate that rotates into various positions responsive to the vehicle wheel being turned. The further the wheel turns, the further the plate rotates and the greater the increase in the roll rate.

Abstract: An electromechanical stabilizer for the chassis of a vehicle, particularly a motor vehicle, is provided having an actuator which is integrated between two stabilizer halves and, as required, rotates the two stablizer halves with respect to one another by a rotation angle. The actuator consists of an electric motor as well as of a transmission connected to the output side of this electric motor. The transmission has a transmission ratio which changes as a function of the angle of rotation. The transmission is designed such that the smallest possible transmission ratio occurs in the neutral position while the stabilizer halves are not rotated with respect to one another. For large angles of rotation, this transmission ratio changes in the “infinite” direction. The transmission having a variable transmission ratio can be constructed for example, as a hypocycloidal transmission with linear guides or as an eccentric transmission.

Abstract: A vehicle roll control system comprises a torsion bar and a first arm extending-substantially perpendicular to the torsion bar. The first arm is fixed to the torsion bar at one end and connectable to one of the axles at the other end. A hydraulic actuator is attached to the torsion bar; and a control connected to the hydraulic actuator controls the operation thereof on detection of a predetermined vehicle condition. The hydraulic actuator comprises a housing, a piston making a sealing sliding fit inside the housing to define a first fluid chamber and a second fluid chamber, and a piston rod connected to the piston and extending through the second fluid chamber and out of the housing.

Abstract: A vehicle roll control system has a torsion bar and a first arm extending substantially perpendicular to the torsion bar. The first arm is fixed to the torsion bar at one end and connectable to one of the axles at the other end. A hydraulic actuator is attached to the torsion bar; and a control connected to the hydraulic actuator controls the operation thereof on detection of a predetermined vehicle condition. The hydraulic actuator comprises a housing, a piston making a sealing sliding fit inside the housing to define a first fluid chamber and a second fluid chamber, and a piston rod connected to the piston and extending through the second fluid chamber and out of the housing.

Abstract: The invention relates to an electromechanical stabilizer for the chassis of a vehicle, particularly a motor vehicle, having-an actuator which is integrated between two stabilizer halves and, as required, rotates the latter with respect to one another by a rotation angle, which actuator consists of an electric motor as well as of a transmission connected to the output side of this electric motor. In this case, the transmission has a transmission ratio which changes as a function of the angle of rotation. The transmission is preferably designed such that the smallest possible transmission ratio occurs in the neutral position while the stabilizer halves are not rotated with respect to one another, and in that, for large angles of rotation, this transmission ratio changes in the “infinite” direction. For example, the transmission which has a variable transmission ratio can be constructed as a hypocycloidal transmission with linear guides or as an eccentric transmission.

Abstract: Improvements for a vehicle stabilizer bar assembly having a pair of stabilizer bar members that are selectively uncoupled via a clutch assembly to provide a vehicle with improved traction. A first improvement concerns a reserve powering apparatus for powering the clutch assembly in the event of an electrical failure that prevents the vehicle power source from transmitting electrical power to the clutch assembly. A second improvement concerns a speed sensing apparatus for inhibiting the operation of the stabilizer bar assembly in a disengaged condition if the speed of the vehicle is greater than or equal to a predetermined speed threshold. A third improvement concerns a logic for controlling the engagement and disengagement of a pair of stabilizer bar assemblies.

Abstract: A vehicle suspension system control unit (40) is arranged to determine from a lateral accelerometer (42) and vehicle speed sensor (44) when the vehicle is executing a series of opposite turns in a slalom type manner which are likely to cause a build-up of body roll. In this situation the roll control system is modified from a regime in which some body roll is allowed, to a regime in which body roll is substantially prevented thereby to prevent the build up of body roll during slalom type maneuvers.

Abstract: Actuator having at least three coupling elements connected with stabilizers (3, 5) and coupling splines (4, 16, 17), wherein one axially movable coupling element (10) is prestressed by a spring (11) while the other coupling elements are firmly connected with said stabilizers, and a pressure chamber (12) whose internal pressure regulates the disengagement operation.

Abstract: A stabilizer bar assembly for a vehicle having a pair of laterally-spaced wheels. The stabilizer bar assembly includes first and second stabilizer bar members and a clutch assembly. Each of the first and second stabilizer bar members is coupled to one of the pair of laterally-spaced wheels. The clutch assembly is coupled to the first and second stabilizer bar members and is operable in a first condition and a second condition. Operation of the clutch assembly in the first condition permits the first and second stabilizer bar members to rotate independently of one another so as to the stabilizer bar assembly from copying the motion of one of the wheels to the other one of the wheels. Operation of the clutch assembly in a second condition couples the first and second stabilizer bar members for rotation with one another, so as to reduce vehicle body roll.

Abstract: A system for roll stabilization of vehicles, in particular motor vehicles, is described, where actuating arrangements are provided. At least one sensor detects a roll parameter, and at least one slewing drive is arranged between halves of the front and/or rear chassis stabilizer, thus creating an initial stress of the stabilizer halves to reduce or suppress the rolling motion and, in the event of roll, applying a counter-torque to the vehicle body as a function of output signals of the sensor. The slewing drive is an electromechanical slewing drive and includes an arrangement for locking the swiveling of the stabilizer halves with respect to one another.

Abstract: A roll control actuator (34) for installation between first and second axially aligned parts (14,16) of a torsion bar (12) has a cylindrical housing (36) connectable by an end wall (38) to the second part of the torsion bar. A rod (40) is positioned inside the housing, extends out of the other end (42) of the housing, and is connectable to the second part of the torsion bar. A cylindrical inner sleeve (46) is positioned inside the housing between the housing and the rod; and the housing, the rod, and the inner sleeve are coaxial on an axis (A), with the rod being rotatable about the axis relative to the housing.

Abstract: A stabilizer effectiveness control device that has an actuator for changing the apparent torsion rigidity of a stabilizer provided between the left and right wheels of a motor vehicle, a control device for controlling the output of the actuator, and a device for detecting the degree of sharpness of a turn when the vehicle is turning. The actuator is driven and controlled in response to the degree of sharpness of the turn when the vehicle is turning so as to change the torsion rigidity of the stabilizer between the left and right wheels of the vehicle. When the sharpness of the turn is small the change in attitude of the vehicle body is controlled by the actuator to prioritize vehicle riding comfort, whereas when the degree of sharpness of the turn is increased the actuator bottoms out, thus allowing the intrinsic rigidity of the stabilizer to control the handling or running stability of the vehicle.

Abstract: A roll control actuator (34) for installation between first and second axially aligned parts (14,16) of a torsion bar comprises a first cylindrical housing (36) connectable at one end (38) to the first part of the torsion bar and having a cylindrical wall (44) with an inner surface (68) and a second cylindrical housing (40) connectable at one end (42) to the second part of the torsion bar and having a cylindrical wall (46) with an inner surface (50,72). The cylindrical wall of the first housing is coaxial with, rotatable relative to, and axially fixed relative to, the cylindrical wall of the second housing. A shaft (62) positioned inside the first and second housings is capable of moving in the axial direction relative to the first and second housings. A first tripot joint (76) is mounted on the shaft and has rollers (80) positioned in helically extending grooves (70) formed in the inner surface of the cylindrical wall of the first housing.