Load-Responsive Transmission "An intelligence independent from electronics"

A passively operating automatic transmission capable of switching its reduction ratio in response to load torque is developed. The reduction ratio is switched by a non-contact magnetic clutch using a passive magnetic mechanism without any accessory components. The absence of mechanical friction at the non-contact magnetic clutch resolves the problems concerning the wear and maintenance, shock while switching the clutch is greatly reduced and the actuator is protected from overloads.

Prototype transmission (80 mm thickness, 97 mm length, 1.6 kg mass)

Simple structure

The transmission passively switches its reduction ratio (SVG 1.2 kB) using only magnetic mechanisms and no accessory components such as actuators, sensors, electronics or power supply are necessary.

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Wear free, maintenance free

The non-contact magnetic clutch eliminates the problems of wear and maintenance.

Moderate transition

Due to the elasticity of the magnetic clutch works as a shock absorber to moderate the transition, the impact and noise while switching reduction ratio is reduced.

Protection against overloads

The actuator is protected from overloads since the magnetic clutch begins to slip (SVG 2.4 kB).

High efficiency

The non-contact magnetic mechanism achieves high efficiency (SVG 1.2 kB) over 85%.

The transmission is a two-stage discrete variable transmission that switches between high and low reduction using a non-contact magnetic clutch. When the load is low, the input is directly connected to the output (low reduction). As the load torque increases, the magnetic clutch switches to a high reduction and the input is transmitted to the output through a pre-reduction device. The magnetic clutch is switched by a passive mechanism exerting alternative axial slide responding to load torque.

Basic configuration

Non-contact magnetic clutch

Low reduction	High reduction

Passive switching mechanism

Low reduction	High reduction

Animated operation (XVL 5.6 kB)

By implementing the load-responsive transmission on the chair-lift (a support equipment that assists a person to stand up by elevating the seat with motor), it is possible to achieve both motion as:

When the user is not seated, low reduction is selected

→ Quick adjusting of the seat height

As the user is seated, high reduction is selected

→ Forceful elevation of the body weight

No special operation for switching the transmission is required of the user.

Chair-lift equipped with load-responsive transmission (video WMV 340 kB)