Abstract: A variable damping force shock absorber includes a cylinder defining therein first and second fluid chambers separated by a valve body. The valve body defines first and second fluid paths for fluid communication between the first and second fluid chambers. A harder damping characteristics valve is associated with the first fluid path. On the other hand, a softer damping characteristics valve is associated with the second fluid path. The valve body has a pair of coaxial arranged grooves. The inner groove is in communication with the first fluid path. Valve seats are formed along respective outer circumference of the inner and outer grooves. The second fluid path is provided with means for varying the fluid path area.

Abstract: An elastically deflectable sensor body has an inner peripheral portion engaging with a first portion of a radially extending wall of a lid closing one end of a cylinder of a shock absorber for movement therewith and an outer peripheral portion engaging with a second portion of the radially extending wall. A first pair of diametrically opposed strain gages and a second pair of diametrically opposed strain gages are placed on the sensor body. A first Wheatstone bridge circuit has the two diametrically opposed strain gages of the first pair in series. A second Wheatstone bridge circuit has the two diametrically opposed strain gages of the second pair in parallel.

Abstract: According to the present invention, a sensor arrangement of a vibration isolation apparatus has a generally annular sensor plate with a plurality of strain sensing elements mounted on a radially extending portion which is elastically deformable upon application of input load. The sensor plate is elastically deformed upon elastic deformation of the radially extending portion.

Abstract: A shock absorber has a cylinder tube coaxially arranged with a strut tube for defining therebetween an annular reservoir chamber and an upper reservoir chamber which is separated from the annular reservoir chamber. A first fluid path is defined for permitting fluid flow from a lower fluid chamber in the cylinder tube to an upper fluid chamber and the annular reservoir chamber in response to bounding stroke of vibration. A second fluid path is also defined for permitting fluid flow from the lower fluid chamber and the annular reservoir chamber to the upper fluid chamber and the upper reservoir chamber, in response to rebounding stroke of vibration. A first flow restriction means is disposed in the first path for generating damping force in response to bounding stroke of vibration, which damping force is variable depending upon the magnitude of the bounding stroke in essentially linear variation characteristics.

Abstract: A rotary actuator comprises a housing made of a synthetic resin. A rotor carrying a plurality of permanent magnet of alternate polarity with respect to the adjacent magnet, and stator having a plurality of electromagnet which is selectively energized, are aligned in axial alignment to each other. Magnetic conductor plates are provided in alignment with the rotor and the stator. The magnetic conductor plates are supported on the inner periphery of the resin housing in opposition to the rotor and the stator for forming part of a magnetic circuit.

Abstract: An automotive suspension system includes means for monitoring bounding and rebounding strokes for producing a stroke indicative signal, and means for detecting frequency of bounding and rebounding strokes based on the stroke indicative signal. The suspension characteristics are hardened when the detected frequency is lower than a predetermined stroke frequency threshold for providing higher driving stability. On the other hand, when the detected stroke frequency is higher than or equal to the stroke frequency threshold, the suspension characteristics are switched between harder suspension characteristics and softer suspension characteristics depending upon stroke position for absorbing vibration energy and assuring riding comfort.

Abstract: A suspension control system is designed to adjust suspension characteristics between hard and soft for bounding and rebounding stroke independently of each other. The system has a sensor means for monitoring speed of a vehicular body as a sprung mass for producing a vehicle body speed indicative signal, which vehicle body speed indicative signal has a variable signal polarity depending upon the direction of vibration, and a sensor means for monitoring relative speed between the vehicular body and a vehicular wheel as an unsprung mass for producing a relative speed indicative signal which also has a variable signal polarity depending upon the direction of relative movement of the vehicular body and the vehicular wheel. A control unit detects a combination of signal polarities of the vehicle body speed indicative signal and the relative speed indicative signal for adjusting damping characteristics for bounding and rebounding vibration independently of each other and depending on the detected combination.

Abstract: A rotary actuator is designed for rotatingly drive a rotary body, such as a rotary valve member for adjusting damping force to be created by a variable damping force shock absorber. The rotary actuator takes a layout of a permanent magnet and an electromagnet arranged in vertically spaced relationship. Vertical layout of the permanent magnet and the electromagnet reduces plane area required for installation.

Abstract: A motor actuator has a rotary member driven by an electric motor and a position encoder for detecting the actuator at a desired position for stopping the motor. The position encoder employs a strategy of arranging a plurality of brush contactors in axially offset arrangement. The axial arrangement of the brush contactor may reduces required radial space.

Abstract: A suspension control system for an automotive vehicle employs a suspension system provided between a vehicle body and a suspension member rotatably supporting a road wheel, the suspension system incorporating means for varying suspension characteristics between at least a first mode with a softer suspension characteristic and a second mode with a harder suspension characteristic. A lateral acceleration sensor is provided for monitoring lateral acceleration exerted on the vehicle body to produce a lateral acceleration indicative signal. A control unit processes the lateral acceleration indicative signal in such a manner that the control unit detects initiation of vehicular rolling on the basis of the sum value for producing a first suspension control signal ordering the second mode and detects termination of vehicular rolling on the basis of magnitude of lateral acceleration for producing a second suspension control signal ordering the first mode.

Abstract: A variable damping characteristics shock absorber includes a piezoelectric unit which serves as a sensor for detecting piston stroke and an actuator for adjusting stiffness of a flow restriction valve and thus for adjusting the damping characteristics of the shock absorber. The shock absorber includes a pair of flow restriction valves, in which one of valve is active in response to a piston bounding stroke for generating damping force by restricting the fluid flow and the other is active in response to a piston rebounding stroke for generating a damping force by restricting fluid flow. The piezoelectric unit is disposed between two valves in such a manner that it may monitor piston strokes both in the bounding and rebounding stroke directions and adjust stiffness of both of the flow restriction valves.

Abstract: An automotive suspension system employs a pressure sensor means designed for monitoring fluid pressure in a fluid chamber of shock absorber to be compressed during piston bounding stroke. Variable suspension characteristics to vary suspension mode between HARD mode and SOFT mode so that suspension mode is normally set in SOFT mode and switched into HARD mode when variation rate of the output of the sensor means becomes greater than a predetermined rate and when the output of the sensor means represents a pressure higher than a predetermined level in the piston bounding stroke.

Abstract: A variable damping characteristics shock absorber includes a piezoelectric transducer which is responsive to piston stroke for producing a piston stroke indicative signal. The piston stroke indicative signal includes component indicative of piston strike direction so as to enable control of the damping characteristics depending upon the piston stroke direction.

Abstract: An automotive suspension system employs a pressure sensor means designed for monitoring fluid pressure in a fluid chamber of shock absorber to be compressed during piston bounding stroke. Variable suspension characteristics to vary suspension mode between HARD mode and SOFT mode so that suspension mode is normally set in SOFT mode and switched into HARD mode when the peak value of variation rate of the output of the sensor means is detected. The suspension system is provided a deadband for maintaining the suspension mode unchanged even when the peak of variation rate is detected.

Abstract: A hydraulic shock absorber is provided a capability of quick response in such an extent that harder damping characteristics is provided during bounding stroke in each vibration cycle and softer damping characteristics is provided during rebounding stoke in each vibration cycle. The hydraulic shock absorber is controlled the damping characteristics for damping road shock by switching damping characteristics between harder damping characteristics and softer damping characteristics during normal mode operation. On the other hand, in attitude change suppression mode, suspension characteristics for suppressing vehicular body attitude change irrespective of the vibration mode.

Abstract: A rotary actuator is designed for rotatingly driving a rotary body, such as a rotary valve member, for adjusting damping force to be created by a variable damping force shock absorber. The rotary actuator takes a layout of a permanent magnet and an electromagnet arranged in vertically spaced relationship. Vertical layout of the permanent magnet and the electromagnet reduces plane area required for installation.

Abstract: An improved control system for electrically adjustable shock absorbers features a fault detector, a system-stop unit, and optional indicators and voltage-supply stabilization systems. The fault detector times the interval between an adjustment command from the operator and completion of the requested shock absorber adjustment, which is itself controlled by a feed-back system. If the adjustment is not completed within a predetermined period of time, the fault detector shuts down the control system via the system-stop unit and may illuminate the optional indicators. A stabilized power supply allows reliable use of the control system in hostile environments such as vehicles, and power-supply current limiting unit prevents electrical overloads in case of short-circuits or the like while facilitating detection of such electrical faults by the fault detector.