Kayaba Industry Company, Ltd.

The Foundation for the Promotion of Industrial Science

Kayaba Kogyo Kabushiki Kaisha

Hideki Yamagata

Tomoyuki Fujita

Koichiro Akatsuka

Hideki Tsuchiya

Yoshiharu Miya

Kenji Yazaki

Mamoru Hosogai

Takuhiro Kondo

Yoshihiro Suda

Masakazu Nakazato

Yoichi Shimoura

Ryuji Naide

Masato Ikeguchi

Kouji Hio

Richard J Hellinga

A solenoid actuator () attached to hydraulic equipment comprises a shaft () connected to the hydraulic equipment, a plunger () fixed to the shaft (), a coil () which magnetically drives the plunger (), and a first bearing () and a second bearing () supporting the shaft () on either sides of the plunger (). A plunger front chamber () is formed between the first bearing () and the plunger (), and a plunger rear chamber () is formed between the plunger () and the second bearing (). By providing a plunger exterior oil passage () on the outside of the plunger () to connect the plunger front chamber () to the plunger rear chamber (), working oil flows through the plunger exterior oil passage () every time the plunger () strokes, thereby preventing a deposit of contaminant on the plunger () without increasing a stroke resistance of the plunger ().

Solenoid actuator

A solenoid actuator () comprises a case () made of a magnetic material and housing a coil () wound on a bobbin (), and a pressure tube () made of a non-magnetic material and fitted into a hollow portion of the bobbin (). A base () and a sleeve () made of a magnetic material are disposed in the pressure tube (). A plunger () provided in an operation chamber () formed in the base () and the sleeve () strokes according to energization of the coil () to axially drive a shaft () fixed to the plunger (). The pressure tube () ensures that magnetic flux is transferred between the case () and the sleeve () while preventing pressure variation in the operation chamber () from being transmitted to the bobbin (), thereby achieving a high response and a pressure tightness in the solenoid actuator ().

A solenoid actuator () attached to a hydraulic equipment comprises a shaft () connected to the hydraulic equipment, a plunger () fixed to the shaft (), a coil () which magnetically drives the plunger (), and a first bearing () and a second bearing () supporting the shaft () on both sides of the plunger (). A plunger front chamber () is formed between the first bearing () and the plunger (), a plunger rear chamber () is formed between the plunger () and the second bearing (), and a second bearing rear chamber () is formed on the opposite side of the second bearing () to the plunger rear chamber (). To secure an oil flow between these chambers, a plunger exterior oil passage (), a second bearing oil passage (), and a shaft-penetrating oil passage () are provided, thereby realizing a preferable balance between oil pressures acting on the second bearing ().

An electromagnetic damper control device including a first member containing a magnet, and a second member containing a solenoid combined to permit relative rotation. The relative rotation of the first and second members induces an electromagnetic force in a solenoid that serves as a damping force to a motion. The device further comprises a current limiter device operated by a voltage generated in the solenoid due to the relative rotation of the first member and second member. The current limiter devices regulates the electrical current flowing in the solenoid to a specific value based on the voltage generated in the solenoid so that by regulating the damping force of the electromagnetic damper a desired damping force can be applied to the electromagnetic damper without requiring external electrical power.

Electromagnetic damper control device

An electromagnetic shock absorber according to the present invention has a shock absorber bodywhich makes telescopic motion in response to an input from outside. The shock absorber bodycomprises a ball screw mechanism, which converts the telescopic motion into rotary motion and is composed of a ball nutand a screw shaft, and power transmitting sectionsandhaving elastic bodies which transmit the rotary motion of the ball screw mechanismto a rotary shaftof a motorwhile shifting a transmission phase when transmission torque of the rotary motion is changed. The motorgenerates electromagnetic resistance to oppose against rotations which input into the rotary shaft. Thus, vibration or the like which inputs into the shock absorber bodyfrom outside is damped by the electromagnetic resistance of the motor. Due to the power transmitting sectionsandwhich delay a rotary phase, moment of inertia of a rotor of the motoris eased when a shocking load inputs into the shock absorber body. Therefore, it is possible to make a vehicle more comfortable to drive when the electromagnetic shock absorber is applied as a shock absorber of the vehicle.

Electromagnetic shock absorber

A magnetic scale formed by arranging a non-magnetic material at a predetermined pitch in the direction of motion of a piston rod, and a pair of magnetic sensors which output two sine waves with a phase difference of 90.degree. corresponding to the pitch of said magnetic scale, are provided. The peak voltages of the sensor output at each pitch of the magnetic scale are updated and stored. Center voltages are computed from the peak voltages at each pitch, and a coarse displacement is computed based on the result of comparing the center voltages and sensor outputs. Correction coefficients of the sensor outputs are computed from the peak voltages and center voltages, and the sensor outputs are compensated based on these correction coefficients. A fine displacement is then computed by an inverse trigonometric function from the two corrected signals, and a displacement signal is output by adding the coarse displacement to the fine displacement.

Growing community of inventors

Sagamihara, Japan

Hideki Yamagata