Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60G—VEHICLE SUSPENSION ARRANGEMENTS
  • B60G17/00—Resilient suspensions having means for adjusting the spring or vibration-damper characteristics, for regulating the distance between a supporting surface and a sprung part of vehicle or for locking suspension during use to meet varying vehicular or surface conditions, e.g. due to speed or load
  • B60G17/015—Resilient suspensions having means for adjusting the spring or vibration-damper characteristics, for regulating the distance between a supporting surface and a sprung part of vehicle or for locking suspension during use to meet varying vehicular or surface conditions, e.g. due to speed or load the regulating means comprising electric or electronic elements
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60G—VEHICLE SUSPENSION ARRANGEMENTS
  • B60G21/00—Interconnection systems for two or more resiliently-suspended wheels, e.g. for stabilising a vehicle body with respect to acceleration, deceleration or centrifugal forces
  • B60G21/02—Interconnection systems for two or more resiliently-suspended wheels, e.g. for stabilising a vehicle body with respect to acceleration, deceleration or centrifugal forces permanently interconnected
  • B60G21/04—Interconnection systems for two or more resiliently-suspended wheels, e.g. for stabilising a vehicle body with respect to acceleration, deceleration or centrifugal forces permanently interconnected mechanically
  • B60G21/045—Interconnection systems for two or more resiliently-suspended wheels, e.g. for stabilising a vehicle body with respect to acceleration, deceleration or centrifugal forces permanently interconnected mechanically between wheels on different axles on the same side of the vehicle, i.e. the left or the right side
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60G—VEHICLE SUSPENSION ARRANGEMENTS
  • B60G21/00—Interconnection systems for two or more resiliently-suspended wheels, e.g. for stabilising a vehicle body with respect to acceleration, deceleration or centrifugal forces
  • B60G21/02—Interconnection systems for two or more resiliently-suspended wheels, e.g. for stabilising a vehicle body with respect to acceleration, deceleration or centrifugal forces permanently interconnected
  • B60G21/04—Interconnection systems for two or more resiliently-suspended wheels, e.g. for stabilising a vehicle body with respect to acceleration, deceleration or centrifugal forces permanently interconnected mechanically
  • B60G21/05—Interconnection systems for two or more resiliently-suspended wheels, e.g. for stabilising a vehicle body with respect to acceleration, deceleration or centrifugal forces permanently interconnected mechanically between wheels on the same axle but on different sides of the vehicle, i.e. the left and right wheel suspensions being interconnected
  • B60G21/055—Stabiliser bars
  • B60G21/0551—Mounting means therefor
  • B60G21/0553—Mounting means therefor adjustable
  • B60G21/0555—Mounting means therefor adjustable including an actuator inducing vehicle roll
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60G—VEHICLE SUSPENSION ARRANGEMENTS
  • B60G2202/00—Indexing codes relating to the type of spring, damper or actuator
  • B60G2202/40—Type of actuator
  • B60G2202/41—Fluid actuator
  • B60G2202/413—Hydraulic actuator
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60G—VEHICLE SUSPENSION ARRANGEMENTS
  • B60G2204/00—Indexing codes related to suspensions per se or to auxiliary parts
  • B60G2204/62—Adjustable continuously, e.g. during driving
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60G—VEHICLE SUSPENSION ARRANGEMENTS
  • B60G2400/00—Indexing codes relating to detected, measured or calculated conditions or factors
  • B60G2400/50—Pressure
  • B60G2400/51—Pressure in suspension unit
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60G—VEHICLE SUSPENSION ARRANGEMENTS
  • B60G2600/00—Indexing codes relating to particular elements, systems or processes used on suspension systems or suspension control systems
  • B60G2600/08—Failure or malfunction detecting means
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60G—VEHICLE SUSPENSION ARRANGEMENTS
  • B60G2800/00—Indexing codes relating to the type of movement or to the condition of the vehicle and to the end result to be achieved by the control action
  • B60G2800/90—System Controller type
  • B60G2800/91—Suspension Control
  • B60G2800/912—Attitude Control; levelling control
  • B60G2800/9122—ARS - Anti-Roll System Control

Definitions

• the hydraulic and electrical control circuit of the vehicle roll control system of Figures 1 to 4 is shown in Figure 5.
• the hydraulic circuit includes a fluid pump 80, a fluid reservoir 81, a first directional valve 82, a second direction valve 83, a third directional valve 84, a first pressure control valve 85, a second pressure control valve 86, and a fluid flow divider 87.
• the fluid flow divider 87 has an input fluidly connected to the pump 80, a first outlet 88 fluidly connected to the input of the first pressure control valve 85, and a second output 89 fluidly connected to the input of the second pressure control valve 86.
• Fluid filters may be positioned after the pump 80 and/or before the reservoir 81.
• Figure 6 illustrates a first alternative of the hydraulic and electrical control circuit of the vehicle roll control system shown in Figures 1 to 4.
• Figure 6 is a modification of the hydraulic circuit shown in Figure 5, in which changes have been made to the first and second directional valves 82,83.
• the second directional valve 883 has five ports 95-99.
• the first port 90 of the first directional valve 882 is fluidly connected to the first output 88 of the flow divider 87 and to the second chamber 60 of the front actuator 34;
• the second port 91 is fluidly connected to the second output 89 of the flow divider and to the second chamber 60' of the rear actuator 34';
• the third port 92 is fluidly connected to the fourth port 98 of the second directional valve 883;
• the fourth port 93 is fluidly connected to the first chamber 58' of the rear actuator 34';
• the fifth port 94 is fluidly connected to the first chamber 58 of the front actuator 34.
• the first port 95 of the second directional valve 883 is fluidly connected to the reservoir 81; the second port 96 is fluidly connected to the pump 80; the third port 97 is fluidly connected to the input of the flow divider 87; the fourth port 98 is fluidly connected to the third port 92 of the first directional valve 882; and the fifth port 99 is fluidly connected to the outputs from the first and second pressure control valves 85,86.
• the first and second ports 95,96 are fluidly connected, and the third, fourth and fifth ports 97-99 are fluidly isolated.
• Figure 7 illustrates a second alternative of the hydraulic and electrical control circuit of the vehicle roll control system shown in Figures 1 to 4.
• Figure 7 is a modification of the hydraulic circuit shown in Figure 5, in which changes have been made to the first and second directional valves 82,83, and in which the third directional valve 84 has been split into two separate valves 84 ',84".
• the first and second ports 90,91 are fluidly isolated from one another and from the third and fourth ports 92,93; and the third and fourth ports are fluidly connected.
• the first and second ports 94,95 are fluidly isolated from one another and from the third and fourth ports 96,97; but the third and fourth ports are fluidly connected.
• the two valves 84', 84" of the third directional valve 84 are substantially identical.
• Each valve 84 ',84" has first and second ports 98, 99.
• the first ports 98 are fluidly connected to the reservoir 81.
• the second port 99 of the first valve 84' is fluidly connected to the second chamber 60 of the front actuator 34.
• the second port 99 of the second valve 84" is fluidly connected to the first chamber 58' of the rear actuator 34'.
• valves 84 ',84" have a de-actuated state as shown in Figure 7 is which the first and second ports 98,99 are fluidly isolated; and an actuated state in which the first and second ports are fluidly connected.
• This second alternative essentially has two actuation modes. In a first mode, the directional valves 82, 84" are actuated, and directional valves 83, 84' are de-actuate, to provide an arrangement substantially the same as in Figure 5B.
• the second port 99 is fluidly connected to the seventh port 96 of the first directional valve 82'.
• the third port 100 is fluidly connected to the sixth port 95 of the first directional valve 82'.
• the fourth port 101 is fluidly connected to the fifth port 94 of the first directional valve 82' .
• the fifth port 102 is fluidly connected (via fluid line 66') to the first chamber 58' of the rear actuator 34'.
• the sixth port 103 is fluidly connected (via fluid line 68') to the second chamber 60' of the rear actuator 34'.
• the seventh port 104 is fluidly connected (via fluid line 66) to the first chamber 58 of the front actuator 34.
• the eighth port 105 is fluidly connected (via fluid line 68) to the second chamber 60 of the front actuator 34.
• the first and eighth ports 90,97 are fluidly connected; the second and seventh ports 92,96 are fluidly connected; the third and sixth ports 92,95 are fluidly connected; and the fourth and fifth ports 93,94 are fluidly connected.
• the first, seventh and eighth ports 90, 96, 97 are fluidly connected; the third, fifth and sixth ports 92,94,95 are fluidly connected; and the second and fourth ports 91,93 are closed.
• the hydraulic circuit includes a fluid pump 480, a fluid reservoir 481, a first pair of pressure control valves 485, 485' associated with the front hydraulic actuator 34, a second pair of pressure control valves 486, 486' associated with the rear hydraulic actuator 34', and a fluid flow divider 487.
• the fluid flow divider 487 has an input fluidly connected to the pump 480, a first outlet 488 fluidly connected to the input of the first pressure control valve 485 associated with the front actuator 34, and a second output 489 fluidly connected to the input of the first pressure control valve 485' associated with the rear actuator 34'.
• the first pair of pressure control valves 485,485' associated with the front actuator 34 are fluidly connected in series, with the output of one valve 485 fluidly connected to the input of the other valve 485'.
• the output of the other valve 485' is fluidly connected to the reservoir 481.
• the second chamber 60 of the front actuator 34 is fluidly connected to the input of the one valve 485 by way of fluid line 68.
• the first chamber 58 of the front actuator 34 is fluidly connected to the output of the one valve 485 by way of fluid line 66.
• the second pair of pressure control valves 486, 486' associated with the rear actuator 34' are fluidly connected in series, with the output of the one valve 486 fluidly connected to the input of the other valve 486' .
• the output of the other valve 486' is fluidly connected to the reservoir 481.
• the second chamber 60' of the rear actuator 34' is fluidly connected to the input of the one valve 486 by way of fluid line 68'.
• the first chamber 58' of the rear actuator 34' is fluidly connected to the output of the one valve 486 by way of fluid line 66' .
• the pump 480 may be driven by the vehicle engine and hence continuously actuated. Alternatively, the pump 480 may be driven by an electric motor or any other suitable means, either continuously, or variably.
• the first pair of pressure control valves 485, 485' are actuated to adjust the pressure differential between the first and second chambers 58,60 of the front hydraulic actuator 34.
• the control module 70 actuates the valves 485, 485', 486, 486' dependent on predetermined vehicle conditions which are determined by signals from one or more sensors, such as a first pressure sensor 76 (which detects the fluid pressure associated with the front hydraulic actuator 34), a second pressure sensor 77 (which detects the fluid pressure associated with the rear hydraulic actuator 34'), a lateral g sensor 74 (which monitors the sideways acceleration of the vehicle), a steering sensor 72 (which monitors the steering angle of the front wheels 12), a vehicle speed sensor 78, and/or any other relevant parameter. If the control module 70 detects that roll control is required
• the first directional valve 482 is solenoid actuated, and has a de actuated state (shown in Figure 10) in which the first and second ports 490, 491 are fluidly connected, and the third and fourth ports 492, 493 are isolated from one another and from the first and second ports. In the actuated state of the first directional valve 482, the first and fourth ports 490, 493 are fluidly connected, and the second and third ports 491, 492 are fluidly connected.
• the second directional valve 483 has a first port 494 fluidly connected to the second output 489 of the flow divider 487; a second port 495 fluidly connected to the output of the one pressure control valve 486 of the second pair; a third port 496 fluidly connected to the first chamber 58' (by way of fluid line 66') of the rear hydraulic actuator 34'; and a fourth port 497 fluidly connected to the second chamber 60' (by way of fluid line 68') of the rear hydraulic actuator 34'.
• the second directional valve 483 is solenoid actuated, and has a de-actuated state (shown in Figure 10) in which the first and second ports 494, 495 are fluidly connected, and the third and fourth ports 496, 497 are isolated from one another and from the first and second ports. In the actuated state of the second directional valve 483, the first and fourth ports 494, 497 are fluidly connected, and the second and third ports 495, 496 are fluidly connected.
• the control module 70 is connected to, and actuates, the directional valves 482, 483 dependent on the predetermined vehicle conditions.
• Figure 11 illustrates a sixth alternative of the hydraulic and electrical control circuit of the vehicle roll control system shown in Figures 1 to 4.
• Figure 11 is a modification of the hydraulic circuit shown in Figure 9 in which a first directional valve 582 is positioned in the fluid lines 68,68', and in which a second directional valve 583 is positioned in the fluid lines 66,66'.
• the first directional valve 582 has a first port 590 fluidly connected to the first output 488 of the flow divider 487; a second port 591 fluidly connected to the second output 489 of the flow divider 487; a third port 592 fluidly connected to the second chamber 60' (by way of fluid line 68') of the rear hydraulic actuator 34'; and a fourth port 593 fluidly connected to the second chamber 60 (by way of fluid line 68) of the front hydraulic actuator 34.
• the first directional valve 582 is solenoid actuated, and has a de-actuated state (shown in Figure 11) in which the first and second ports 590, 591 are fluidly connected, and the third and fourth ports 592, 593 are fluidly connected but isolated from the first and second ports.
• the second directional valve 583 has a first port 594 fluidly connected to the output of the one pressure control valve 485 of the first pair; a second port 595 fluidly connected to the output of the one pressure control valve 486 of the second pair; a third port 596 fluidly connected to the first chamber 58' (by way of fluid line 66') of the rear hydraulic actuator 34'; and a fourth port 597 fluid connected to the first chamber 58 (by way of fluid line 66) of the front hydraulic actuator 34.
• the second directional valve 583 is solenoid actuated, and has a de-actuated state (shown in Figure 11) in which the first and second ports 594, 595 are fluidly connected, and the third and fourth ports 596,597 are fluidly connected but isolated from the first and second ports. In the actuated state of the second directional valve 583, the first and fourth ports 594, 597 are fluidly connected, and the second and third ports 595, 596 are fluidly connected.
• the control module 70 is connected to, and actuates, the directional valves 582, 583 dependent on the predetermined vehicle conditions.
• the operation of this sixth alternative is substantially the same as the operation of the arrangement shown in Figure 10.
• Figure 12 illustrates a seventh alternative of the hydraulic and electrical control circuit of the vehicle roll control system shown in Figures 1 to 4.
• Figure 12 is a modification of the hydraulic circuit shown in Figure 10 in which the first and second directional valves have been combined into a single directional valve 682 is positioned in the fluid lines 66,66', 68,68'.
• the directional valve 682 has a first port 690 fluidly connected to the first output 488 of the flow divider 487; a second port 691 fluidly connected to the output of the one pressure control valve 485 of the first pair; a third port 692 fluidly connected to the first chamber 58 (by way of fluid line 66) of the front hydraulic actuator 34; and a fourth port 693 fluidly connected to the second chamber 60 (by way of fluid line 68) of the front hydraulic actuator 34.
• the directional valve 682 has a fourth port 694 fluidly connected to the second output 489 of the flow divider 487; a fifth port 695 fluidly connected to the output of the one pressure control valve 486 of the second pair; a seventh port 696 fluidly connected to the first chamber 58' (by way of fluid line 66') of the rear hydraulic actuator 34'; and an eighth port 697 fluidly connected to the second chamber 60' (by way of fluid line 68') of the rear hydraulic actuator 34'.
• the directional valve 682 is solenoid actuated, and has a de-actuated state (shown in Figure 12) in which the first and second ports 690, 691 are fluidly connected, the third and fourth ports 692, 693 are isolated from one another and from the other ports, the fifth and sixth ports 694, 695 are fluidly connected, and the seventh and eighth ports 696, 697 are isolated from one another and from the other ports.
• the first and fourth ports 690, 693 are fluidly connected
• the second and third ports 691, 692 are fluidly connected
• the fifth and eighth ports 694, 697 are fluidly connected
• the sixth and seventh ports 695, 696 are fluidly connected.
• the control module 70 is connected to, and actuates, the directional valve 682 dependent on the predetermined vehicle conditions.
• the operation of this seventh alternative is substantially the same as the operation of the arrangement shown in Figure 10.
• Figure 13 illustrates an eighth alternative of the hydraulic and electrical control circuit of the vehicle roll control system shown in Figures 1 to 4.
• Figure 13 is a modification of the hydraulic circuit shown in Figure 12.
• the directional valve 782 has a first port 790 fluidly connected to the first output 488 of the flow divider 487; a second port 791 fluidly connected to the output of the one pressure control valve 485 of the first pair; a third port 792 fluidly connected to the first chamber 58 (by way of fluid line 66) of the front hydraulic actuator 34; and a fourth port 793 fluidly connected to the second chamber 60 (by way of fluid line 68) of the front hydraulic actuator 34.
• the directional valve 782 has a fourth port 794 fluidly connected to the second output 489 of the flow divider 487; a fifth port 795 fluidly connected to the output of the one pressure control valve 486 of the second pair; a seventh port 796 fluidly connected to the first chamber 58' (by way of fluid line 66') of the rear hydraulic actuator 34'; and an eighth port 797 fluidly connected to the second chamber 60' (by way of fluid line 68') of the rear hydraulic actuator 34' .
• the directional valve 782 is solenoid actuated, and has a de-actuated state (shown in Figure 13) in which the first and second ports 790, 791 are fluidly connected, the fifth and sixth ports 794, 795 are fluidly connected, the third and seventh ports 792, 796 are fluidly connected, and the fourth and eighth ports 793, 797 are fluidly connected.
• the first and fourth ports 790, 793 are fluidly connected
• the second and third ports 791, 792 are fluidly connected
• the fifth and eighth ports 794, 797 are fluidly connected
• the sixth and seventh ports 795, 796 are fluidly connected.
• the control module 70 is connected to, and actuates, the directional valve 782 dependent on the predetermined vehicle conditions.
• the operation of this eighth alternative is substantially the same as the operation of the arrangement shown in Figure 10.
• the above-described embodiments of Figures 9 to 13 all operate in substantially the same way, but provide different hydraulic circuit arrangements for their respective fail-safe modes, as illustrated in the drawings. Also, the selection is dependent on the type of hydraulic actuator that is used.
• the valves of the hydraulic circuit are actuable to provide fluid pressure to the first fluid chamber of the front hydraulic actuator which is different from the fluid pressure provided to the first fluid chamber of the rear hydraulic actuator; and/or actuable to provide fluid pressure to the second fluid chamber of the front hydraulic actuator which is different from the fluid pressure provided to second fluid chamber of the rear hydraulic actuator.
• the directional valves are solenoid actuated.
• the directional valves may be hydraulically actuated by first and second pilot (on/off) valves, which pilot valves are controlled by the control module 70.
• the present invention is also applicable for use with a vehicle roll control system, the front portion 122 of which is as shown in Figure 14 and the rear portion of which is substantially identical to the front portion.
• the front portion 122 comprises a torsion bar 126, a first arm 128, and a hydraulic actuator 134.
• the first arm 128 is fixed at one end 138 to one end 140 of the torsion bar 126.
• the other end 142 of the first arm 128 is connected to one of the shock absorbers 120.
• the hydraulic actuator 134 has a piston rod 164 which is fixed to the other end 187 of the torsion bar 126.
• the housing 156 of the actuator 134 is connected to the other shock absorber 120.
• the hydraulic actuator 134 is substantially the same as the actuator 34 described above with reference to Figures 1 to 5, and has a fluid line 166 connected to a first fluid chamber inside the housing, and another fluid line 168 connected to a second fluid chamber inside the housing.
• the first and second fluid chambers inside the housing 156 are separated by a piston secured to the piston rod 164.
• the fluid lines 166,168 for each hydraulic actuator are connected to a hydraulic circuit as shown in Figure 5, which is controlled by a control circuit as shown in Figure 5, or any one of the arrangements shown in Figures 6 to 13.
• the roll control system is operated in substantially the same manner as that described above with reference to Figures 1 to5, or any one of Figures 6 to 13.
• the present invention is also applicable for use with a vehicle roll control system as shown in Figure 15.
• the front portion 222 of the system comprises a torsion bar 226, a first arm 228, a second arm 228', and a hydraulic actuator 234.
• the rear portion of the system is substantially identical.
• the first arm 228 is fixed at one end 238 to one end 240 of the torsion bar 226.
• the other end 242 of the first arm 228 is connected to one of the shock absorbers 220.
• the second arm 228' is fixed at one end 238' to the other end 287 of the torsion bar 226.
• the other end 242' of the second arm 228' is connected to the other shock absorber 220'.
• the torsion bar 226 is split into first and second parts 290,292, respectively.
• the first and second parts 290,292 of the torsion bar 226 have portions 294,296, respectively, which are axially aligned.
• the axially aligned portions 294,296 are connected by a hydraulic actuator 234.
• the hydraulic actuator 234, as shown in Figure 16, comprises a cylindrical housing 256 which is connected at one end 239 to the portion 294 of the first part 290 of the torsion bar 226.
• the actuator 234 further comprises a rod 241 positioned inside the housing 256, extending out of the other end 243 of the housing, and connectable to the portion 296 of the second part 292 of the torsion bar 226.
• the rod 241 has an external screw thread 249 adjacent the housing 256.
• Balls 251 are rotatably positioned in hemispherical indentations 253 in the inner surface 255 of the housing 256 adjacent the screw thread 249.
• the balls 251 extend into the screw thread 249.
• the rod 241 is slidably and rotatably mounted in the housing 256 at the other end 243 by way of a bearing 259 positioned in the other end 243. This arrangement allows the rod 241 to rotate about its longitudinal axis relative to the housing 256, and to slide in an axial direction A relative to the housing.
• a piston chamber 261 is defined inside the housing 256.
• the rod 241 sealing extends into the piston chamber 261 to define a piston rod 264, and a piston 262 is secured to the end of the piston rod inside the piston chamber.
• the piston 262 makes a sealing sliding fit with the housing 256 and divides the chamber 261 into a first fluid chamber 258 and a second fluid chamber 260.
• the first fluid chamber 258 is fluidly connected to fluid line 266, and the second fluid chamber 260 is fluidly connected to fluid line 268.
• the fluid lines 266,268 are connected to a hydraulic circuit as shown in Figure 5, which is controlled by a control circuit as shown in Figure 5, or any one of the arrangements shown in Figures 6 to 13.
• the roll control system 222 is operated in substantially the same manner as that described above with reference to Figures 1 to 5, or any one of Figures 6 to 13 An alternative arrangement for the hydraulic actuator of Figure 16 is shown in Figure 17.
• the actuator 334 comprises a cylindrical housing 356 which is connected at one end 339 to the portion 294 of the first part 290 of the torsion bar 226.
• the actuator 334 further comprises a rod 341 positioned inside the housing 356, extending out of the other end 343 of the housing, and connectable to the portion 296 of the second part 292 of the torsion bar 226.
• the rod 341 has an external screw thread 349 adjacent the housing 356.
• Balls 351 are rotatably positioned in hemispherical indentations 353 in the inner surface 355 of the housing 356 adjacent the screw thread 349. The balls 351 extend into the screw thread 349.
• the rod 341 is slidably and rotatably mounted in the housing 356 at the other end 343 of the housing by way of a bearing 359 positioned in the other end.
• the rod 341 makes a sliding guiding fit with the inner surface 355 of the housing 356 at its end 341' remote from the second part 292 of the torsion bar 226. This arrangement allows the rod 341 to rotate about its longitudinal axis relative to the housing 356, and to slide in an axial direction A relative to the housing.
• First and second fluid chambers 358,360 are defined inside the housing 356.
• the rod 341 makes a sealing fit with the inner surface 355 of the housing 356 by way of seal 371 to define a piston 362.
• the first fluid chamber 358 is positioned on one side of the piston 362, and the second fluid chamber 360 is positioned on the other side of the piston.
• a seal 369 is positioned adjacent the bearing 359.
• a portion 364 of the rod 341 defines a piston rod which extends through the second fluid chamber 360.
• the first fluid chamber 358 is fluidly connected to fluid line 366, and the second fluid chamber 360 is fluidly connected to fluid line 368.
• the fluid lines 366,368 are fluidly connected with one of the hydraulic circuits shown in Figures 5 to 8 to actuate the actuator 334.
• a further alternative arrangement of hydraulic actuator 334' is shown in Figure 18.
• the actuator 334' is substantially the same as the actuator 334 shown in Figure 17, but without the sliding guiding fit of the free end 341' of the rod 341 with the housing 356.
• the cross-sectional area of the first fluid chamber of each hydraulic actuator described above is substantially double the cross-sectional area of the piston rod of the hydraulic actuator, when considered on a radial basis.
• a hydraulic actuator is provided for both the front of the vehicle and the rear of the vehicle, and these hydraulic actuators are substantially the same.
• the hydraulic actuator for the front of the vehicle may be a different type to the hydraulic actuator for the rear of the vehicle.
• the hydraulic actuator may include a check valve (not shown, but preferably mounted in the piston) which allows flow of hydraulic fluid from the first fluid chamber to the second fluid chamber only when the fluid pressure in the first fluid chamber is greater than the fluid pressure in the second fluid chamber.
• the second fluid chamber can be connected to a reservoir during servicing of the actuator to bleed air from the hydraulic fluid.
• the presence of the check valve reduces the risk of air being sucked into the second fluid chamber should the fluid pressure in the second fluid chamber fall below the fluid pressure in the first fluid chamber, and provides further improvements in ride comfort.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Vehicle Body Suspensions (AREA)

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• 2004
  • 2004-05-10 GB GB0410357A patent/GB0410357D0/en not_active Ceased
• 2005
  • 2005-04-27 EP EP05736186A patent/EP1747106A1/de not_active Withdrawn
  • 2005-04-27 WO PCT/EP2005/004508 patent/WO2005108127A1/en not_active Application Discontinuation

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