Suspension provided with a load responsive device

Abstract

A vehicle suspension comprises a hub carrier on which a wheel hub is suitable for being mounted, a suspension arm having an outer end connected to the hub carrier by a ball joint and an inner end suitable for being attached to a suspended structure of the vehicle, and a shock absorber. At least one load responsive device is arranged on the suspension arm, the load responsive device comprising a sensor able to generate an output signal in response to a load applied to the suspension arm, wherein a control unit is configured to receive the output signal generated by the sensor and to adjust the stiffness of the shock absorber through a valve adapted to vary passage cross-sections of the fluid contained in the shock absorber.

Claims

1. A vehicle suspension, comprising a hub carrier, on which a wheel hub is suitable for being mounted, a suspension arm having an outer end connected to the hub carrier by a ball joint and an inner end suitable for being attached to a suspended structure of a vehicle, and a shock absorber, wherein at least one load responsive device is arranged on the suspension arm, said load responsive device comprising a sensor generating an output signal in response to a load applied to the suspension arm, wherein a control unit is configured to receive the output signal generated by the sensor and to adjust stiffness of the shock absorber through a valve adapted to vary passage cross-sections of fluid contained in the shock absorber, and wherein said load responsive device is arranged between the ball joint and a seat that houses the ball joint on the outer end of the suspension arm.

2. The vehicle suspension of claim 1, wherein the control unit is configured to adjust motion of the vehicle based on said output signal.

3. A vehicle suspension, comprising a hub carrier configured to have a wheel hub mounted thereon, a suspension arm having an outer end connected to the hub carrier by a ball joint and an inner end adapted to be attached to a suspended structure of a vehicle, a shock absorber, and a valve adapted to vary fluid-passage cross-sections through the shock absorber to change stiffness of the shock absorber, said vehicle suspension further comprising at least one load responsive device fitted at the ball joint, said load responsive device comprising a fluid device fluidically connected to the valve and able to generate a fluid pressure in response to a load applied to the ball joint.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a representation of a vehicle in a Cartesian coordinate system;

(2) FIG. 2 schematically represents a first embodiment of a suspension according to the present disclosure;

(3) FIG. 3 schematically represents an embodiment of a suspension not according to the present disclosure;

(4) FIG. 4 schematically represents a second embodiment of a suspension according to the present disclosure;

(5) FIG. 5 represents a prospective view of a detail of the suspension in FIG. 4; and

(6) FIG. 6 is a cross-sectional view taken along the line A-A of FIG. 5.

DETAILED DESCRIPTION

(7) In FIGS. 2, 3 and 4, a MacPherson-type suspension is shown, indicated collectively at 1.

(8) It is understood, however, that the present disclosure is not limited to such type of suspension but applies in general to any type of suspension for a vehicle wherein, on a connecting member between the suspended structure of the vehicle and the wheel, a load may be detected in the event of acceleration, braking or steering.

(9) For the purposes of the present disclosure, connecting member means any member, including an arm, a hinge, a rod, a lever, and a hub carrier, which connects the suspended structure of the vehicle to the wheel hub and transmits the forces at play.

(10) The suspension 1 shown in FIG. 2 comprises a hub carrier 2, on which may be mounted the hub of a wheel (not shown), comprising an upper end 2a and a lower end 2b.

(11) The suspension 1 further comprises a spring-shock absorber unit 3 comprising a shock absorber 4 and a spring 5. The spring-shock absorber unit 3 has a lower end 3a rigidly connected to the upper end 2a of the hub carrier 2 and an upper end 3b adapted to be connected to a suspended structure S of the vehicle.

(12) The suspension 1 further comprises a three-point suspension arm 6 having a fork shape, arranged transversely to the longitudinal (and running) direction of the vehicle. The suspension arm 6 has an outer end 6a connected by a spherical hinge to the lower end 2b of the hub carrier 2 and to two internal ends 6b (corresponding to the two branches of the suspension arm) suitable to be connected by a hinge to the suspended structure S of the vehicle. In FIG. 2, reference numeral 7 indicates a ball joint placed in a seat obtained at the external end 6a of the suspension arm, and reference numeral 8 indicates silent-block bushings arranged in respective seats made in the inner ends 6b of the suspension arm.

(13) At least one load responsive device is located on the suspension arm 6 and/or on the hinge of the outer end of the suspension arm and/or on the hinges of the inner ends of the suspension arm and/or on the hub carrier. Such load responsive device is able to generate an output signal in response to a load applied to the suspension arm 6.

(14) In the embodiment of FIG. 2, the load responsive device is configured as a sensor able to generate an output signal in response to a load applied to the suspension arm 6. In particular, FIG. 2 illustrates two sensors 10 positioned on the respective branches of the suspension arm 6, two sensors 20 positioned between the respective silent-block bushings 8 and the respective seats that house the silent-block bushings, and one sensor 30 positioned between the ball joint 7 and the seat that houses the ball joint 7, obtained at the outer end 6a of the suspension arm 6.

(15) The sensors 10, 20 and 30 also allow to detect individually the loads to which the suspension arm 6 is subjected when the vehicle is cornering, accelerating or braking. When properly positioned, the sensors also allow differentiation between loads due to acceleration and loads due to braking.

(16) The sensors 10, 20, 30 may be strain sensors, pressure sensors or displacement sensors or any other type of sensor adapted to detect the loads to which the arm is subjected.

(17) The sensors 10, 20, 30 are operatively connected to a control unit 40 configured to receive the output signal generated by the sensors 10, 20, 30 and to adjust the motion of the vehicle based on such output signal.

(18) Alternatively or in combination, the control unit 40 may be configured to adjust the viscous damping coefficient of the shock absorber 4, or to control a valve V to adjust the fluid passage cross-sections contained in the shock absorber, based on the output signal of the sensors 10, 20, 30.

(19) Alternatively or in combination, the control unit 40 may be configured to control a fluid roll control cylinder (not shown) located between the hub carrier and the shock absorber and/or spring member, or to control an active suspension actuator (not shown) based on the output signal.

(20) The output signals from sensors 10, 20, 30 may be combined with those from other sensors placed on the vehicle to achieve greater accuracy. For example, a useful sensor could be a thermometer and/or a hygrometer, to estimate the tire friction coefficient.

(21) FIG. 3 illustrates an embodiment not according to the present invention. The same reference numbers have been assigned to elements corresponding to those of the preceding embodiment. Such elements will not be described further.

(22) In the embodiment of FIG. 3, the load responsive device is configured as a fluid cylinder 50 (in the example, two cylinders positioned on the branches of the suspension arm 6) able to generate a fluid pressure (e.g. by compression of cylinders) in response to a load applied to the suspension arm 6. A roll control actuator or cylinder 60, fluidically connected to the fluid cylinder 50, is arranged between the hub carrier 2 and the spring-shock absorber unit 3 to adjust the height of the spring-shock absorber unit 3 in response to the fluid pressure generated by the fluid cylinder 50. A pressure multiplier 70 may be installed between the fluid cylinder 50 and the roll control cylinder 60.

(23) According to alternative embodiments (not shown), in place of the spring-shock absorber unit, only a spring, or only a shock absorber, may be used.

(24) According to alternative embodiments (not shown), instead of the fluid cylinder, another type of fluid device may be positioned in the area of the joint or the silent-block bushings or in any area of the connecting members, which may have any configuration (for example a membrane or a deformable wall) so as to generate a fluid outlet/inlet following a load applied to the connecting member itself.

(25) When the vehicle is cornering, the fluid cylinders 50 compress, sending the fluid contained therein to the pressure multiplier 70 which in turn sends it into the roll control cylinder 60 placed between the hub carrier 2 and the spring-shock absorber unit. 3.

(26) A flow measurement sensor (not shown) may be positioned between the cylinder 50 and the cylinder 60. Such flow measurement sensor is operatively connected to a control unit (not shown) configured to receive the output signal generated by the sensor and to adjust the motion of the vehicle on the basis of such output signal, with the possible aid of a temperature and/or humidity sensor.

(27) Alternatively or in combination, the control unit may be configured to adjust the viscous damping coefficient of the shock absorber 4, and/or to control an active suspension actuator (not shown), based on the output signal of the flow measurement sensor.

(28) The control implemented by the system described above may be combined with the control implemented by sensors located on the vehicle.

(29) According to a further embodiment (not shown), a roll control cylinder connected to a fluid reservoir may be provided between the hub carrier and the spring-shock absorber unit, the spring or the shock absorber. Such cylinder may be controlled by a control unit on the basis of signals supplied by sensors arranged on one or more connecting members of the suspension.

(30) FIG. 4 illustrates a second embodiment of the present disclosure. The same reference numbers have been assigned to elements corresponding to those of the preceding embodiments. Such elements will not be further described.

(31) In the embodiment of FIG. 4, the load responsive device is configured as a fluid cylinder 50 (in the example, two cylinders positioned on the branches of the suspension arm 6, or alternatively a fluid device 50 located in the joint area, or alternatively a fluid device 50 located in the area of the silent-block bushings) able to generate a fluid pressure (e.g. by compressing the cylinders) in response to a load applied to the suspension arm 6. The shock absorber may vary its stiffness as the size of the fluid passage cross-sections contained therein varies, through an adjustment valve V. Such valve is in turn controlled by the pressure of the fluid of the load responsive device 50.

(32) According to alternative embodiments (not shown), instead of the fluid cylinder, another type of fluid device may be positioned in the area of the connecting members, which may have any configuration (for example a membrane or a deformable wall) so as to generate a fluid outlet/inlet following a load applied to the connecting member.

(33) With reference to FIGS. 5 and 6, a fluid device 50 is arranged at the ball joint 7. The ball joint conventionally comprises a ball shank 7a for connecting to the hub carrier 2, a ball joint body 7b and a plastic bearing 7c interposed between the ball shank 7a and the ball joint body 7b. The ball joint further comprises a support 7d of elastomeric material provided with an armature 7e made of metallic material, through which the body 7b of the ball joint is connected to the end 6a of the suspension arm 6. In the illustrated example, the fluid device 50 is made as a pair of chambers in the support 7d made of elastomeric material and filled with fluid. The chambers of the fluid device 50 are fluidically connected to the adjustment valve V by small connection tubes 51.

(34) When the vehicle is cornering, the fluid devices 50 compress, sending the fluid contained therein to the adjustment valve V that adjusts the stiffness of the shock absorber.

(35) A flow measurement sensor (not shown) may be positioned between the cylinder 50 and the adjustment valve of the shock absorber. The flow measurement sensor is operatively connected to a control unit (not shown) configured to receive the output signal generated by the sensor and to adjust the motion of the vehicle on the basis of such output signal, with the possible aid of a temperature and/or humidity sensor.

(36) Alternatively or in combination therewith, the control unit (not shown) may be configured to adjust the viscous damping coefficient of the shock absorber 4, and/or to control an active suspension actuator (not shown), based on the output signal of the flow measurement sensor.

(37) The control carried out by the system described above may be combined with the one carried out by sensors located on the vehicle.