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Electromagnetic Absorber is a new type of intelligent independent suspension system using electromagnetic response. It uses a variety of sensors to detect road conditions and various driving conditions, and transmits them to the electronic controller ECU, which controls the electromagnetic shock absorber to respond instantly, suppress vibration, and maintain the stability of the vehicle body, especially at high speeds and unexpected obstacles. It can even show its advantages. The response speed of the electromagnetic shock absorber is up to 1000 Hz, which is 5 times faster than the traditional shock absorber, which completely solves the problem that the comfort and stability of the traditional shock absorber cannot be balanced, and can adapt to changing driving conditions and arbitrary roads. Excitation, even on the most bumpy roads, electromagnetic shock absorbers can ensure the smooth running of motorcycles, representing the direction of shock absorber development.

Electromagnetic shock absorber

Hitachi

Take the electromagnetic shock absorber developed by Hitachi Japan as an example. This is an active suspension system consisting of a sensor, an electronic controller ECU, a cylindrical linear motor and a spring hydraulic shock absorber. .

The sensors in the system are acceleration sensors and suspension stroke sensors. The acceleration sensor is used to detect the degree of unevenness on the road surface, and sends it to the electronic controller ECU to send instructions to control the linear motor to generate a reaction force motion stroke that is completely opposite to the direction of shock absorber movement to reduce the vibration of the vehicle. The suspension stroke sensor is used to detect the actual motion stroke of the shock absorber, and then feed it back to the electronic controller ECU to correct the reaction force motion stroke of the linear motor in a timely manner.

Core components in the system

It is a linear motor and an electronic controller ECU. The linear motor is actually a linear motor composed of a stator coil and a moving magnet. Its working principle is the same as that of an ordinary rotary motor. The ordinary rotary electric motor uses a change in current to generate a rotating magnetic field in a stator coil of the electric motor, and induces rotation of a rotor magnet. The linear motor can be regarded as a common rotary motor cut from the center of the circle along the radius and then unfolded straight, so that the originally rotating magnetic field becomes a magnetic field traveling in a straight direction, and the rotation of the rotor also becomes a linear movement.

System control of current

The stator coil of a linear motor installed under the spring hydraulic shock absorber is fixed on the shock absorber cylinder. The current intensity in the coil is directly controlled by the electronic controller ECU. The electronic controller ECU detects the actual condition of the road surface based on the acceleration sensor. And the actual motion stroke detected by the suspension stroke sensor, sends instructions to precisely control the strength of the current input to the stator coil, so as to accurately control the linear motor's anti-direction motion damping force and vibration damping force, and alleviate the impact and vibration of the road surface. The larger the input current, the stronger the magnetic field generated in the stator coil, and the greater the damping and damping forces generated by the linear motor in the opposite direction. It can be seen that the system's control of the current is completely related to the driving acceleration and road bumps To adapt.

This means that you can choose the best damping force based on various road and load conditions. When the vehicle is driving on rough and rough roads or changed from single driving to double riding, and the wheels bounced violently, the system automatically controls the stator coil to input a larger current, so that the linear motor generates the opposite direction of the shock absorber. The greater damping force and damping force can offset the severe vibration of the shock absorber. The electronic controller ECU can continuously change the resistance and damping force of the shock absorber 1,000 times within 1 S. Compared with the use of a spring hydraulic shock absorber alone, it can improve the response speed and comfort. The fastest and most advanced intelligent suspension system in the world.

Compared with the non-linear motor, the linear motor can reduce the vibration of the vibration frequency around 1.5 Hz by 8 dB. At present, the electromagnetic shock absorber has been installed on SUV (Sports Utility Vehicles) sports utility vehicles and has been tested, and a large amount of actual driving data has been obtained. It is expected to be installed in small batches on SUV cars and large displacement sports motorcycles by 2009.

Electromagnetic shock absorber developed by Hitachi

Japan

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The high-density permanent magnet set is embedded in the moving piston, and the piston rod is fixed on the shock absorber cylinder through nylon sliding bearings at both ends. A proper gap is left between the cylinder and the piston, so that the permanent magnet piston can be inside the cylinder. Freely reciprocating sliding; the stator coil on the cylinder is connected to the external electronic controller ECU through a connecting wire. When an electric vehicle runs on a road with good vibration damping performance, the lower end of the shock absorber is directly connected to the wheel or the cradle, so the permanent magnet piston in the shock absorber is moved up and down, and the strong magnetic field formed by the high-density permanent magnet is constantly The stator coil is cut, so that the stator coil generates inductive AC power, which is converted into DC power after rectification, and is sent to an electronic control switch. An electronic switch directly controlled by the electronic controller ECU converts the induced electromotive force generated on each electromagnetic shock absorber (average 25 w per stem) and the induced electromotive force generated on other electronic devices (such as brake regeneration current) Collect it and send it to

Electromagnetic rheological shock absorber. The piston of the shock absorber is wound with an electromagnetic coil. When no current passes through the electromagnetic coil, the electromagnetic fluid in the four micro-channels in the piston is not magnetized, and the irregularly arranged magnetic particles are uniformly distributed. In the state, the damping force is the same as that of ordinary damping oil; once the control unit sends out a pulse signal, a voltage will be generated in the coil, which will form a magnetic field and change the arrangement of particles. These particles will be arranged immediately in a direction perpendicular to the movement of the piston, hindering the flow of oil in the micro-channel of the piston, and improving the damping effect. The greater the intensity of the current input into the piston coil, the stronger the magnetic field formed, the better the magnetic particles are magnetized, and the greater the damping force generated. It can be seen that the magnitude of the damping force generated by the magnetorheological fluid changes with the magnitude of the input current. The electronic controller ECU can accurately and accurately control the current intensity of the input piston coil in a timely and accurate manner according to the road conditions and load conditions. The shock absorption performance of the shock absorber achieves the best effect of perfect uniformity of comfort and sportiness, which can ensure the smooth driving of the vehicle even on the most bumpy roads. ^[1]