PROBLEM TO BE SOLVED: To provide a maximum speed limiting device of a bicycle, which limits automatically the maximum speed of a bicycle independently of the intention of a driver. SOLUTION: A magnet 34 is fixed on the frame side, and a rotatable conducting plate 42 which can expand in the radial direction is coupled with the wheel side. Rotation of the wheel is transferred to the conducting plate 42, which is energized to the closed side with a coil spring (elastic body) 45. When the rotating speed of the wheel exceeds a specified value, the conducting plate 42 rotating together with the wheel expands, and a braking force F is generated coping with the magnet 34 fixed on the frame side. When the running speed of a bicycle increases and the rotating speed of the wheel exceeds the prescribed value, an electromagnetic force due to an eddy current is generated as the braking force F, and applies damping to the rotation of the wheel, so that the running speed of the bicycle is kept at most a prescribed value, independently of the intention of a driver. Thereby the maximum speed is automatically limited.

Maximum speed limiting device of bicycle

In one embodiment, the device comprises a first member in a kinematic relationship with at least one further member to form a system. The system interacts when an external energising force is imposed on the system causing the members to respond due to their kinematic and dynamic characteristics and thereby creating relative motion between the members. A trigger member is coupled to the at least the first member and moves in response to a pre-determined system movement. When the trigger member moves, the trigger member imposes a braking action on the system or members thereof. The speed or intensity of the braking action imposed by the trigger member on the system or members thereof is controlled by the trigger member rate of movement. This rate of movement is in turn governed by a magnetic flux interaction between the trigger member and the at least one first member causing formation of a magnetically induced eddy current force between the parts.

Tuning of a kinematic relationship between members

A single row rotating-type eddy current braking apparatus for use with a rotor mounted on a powered shaft comprises a support ring, a plurality of magnets, a plurality of ferromagnetic switching plates, and a support body. The switching plates or magnets are capable of rotating with respect to each other to effect braking. The dimensions of the switching plates and angular displacement of the magnets and switching plates are controlled to minimize drag torque when in a non-braking state. The switching plates can be made to rotate and the bearing can be employed in combination with the rotating and stationary components to alleviate problems such as thermal expansion and wear. The apparatus also utilizes a pneumatic cylinder designed to rotate in the direction of the shaft rotation to achieve a braking state, and can employ a single rod double acting cylinder to switch between braking and non-braking states.

Eddy current braking apparatus

This eddy-current retarding device includes: a magnet holding member that is coaxially provided to a rotating shaft and holds plural permanent magnets in a circumferential direction; a brake member that includes paired disk portions disposed on both sides of the magnet holding member in the axial direction of the rotating shaft, a connecting portion that connects the paired disk portions, and an eddy-current generating portion that causes eddy current due to rotation of the permanent magnets, and this brake member being supported in a relatively rotatable manner with respect to the rotating shaft; and a friction brake that causes a friction member to press against the brake member at the time of braking to bring the brake member to a stop.

Eddy-current retarding device

PROBLEM TO BE SOLVED: To provide a parasol type magnet braking device which naturally brakes when the rotational speed exceeds the specified range, so that the rotational speed is not increased. SOLUTION: A plurality of arms 11, 11, etc., to be opened outwardly are fitted to a perpendicular rotary shaft 3 in a oscillating manner, magnets 13, 13, etc., are attached to a tip of the arms, a fixed cylinder 14 formed of a nonmagnetic metal is provided outside the arms in a concentric manner with the rotary shaft 3, the arm 11 is opened by the centrifugal force when the rotational speed of the rotary shaft is increased, and the clearance from the fixed cylinder 14 is decreased to apply a brake.

Parasol-type magnet brake, and high-speed vertical-axis rotary body

PROBLEM TO BE SOLVED: To provide an eddy current speed reducer which has a mechanism for automatically returning a magnet support cylinder to a non-braking position, prevents the occurrence of drag torque at the time of non-braking, and possesses a simple device configuration. SOLUTION: The eddy current speed reducer is equipped with a brake drum 7 coupled with a rotating shaft, an immovable guide cylinder disposed in the brake drum and provided with an inner cavity with a rectangular cross section, a magnet support cylinder 14 provided in the inner cavity, a plurality of magnets 24 provided on the outer peripheral surface of the magnet support cylinder at equal intervals in the peripheral direction so that polarities alternately change, and a plurality of ferromagnetism parts provided on positions corresponding to the magnets. The respective ferromagnetism parts 121 and coupled parts 122 form an integral ferromagnetic 15, and an actuator 20 is provided which is connected to the magnet support cylinder 14 so as to rotate the magnet support cylinder 14 in the peripheral direction and in the direction opposite to the usual rotation of the brake drum 7 from the non- braking position, in which two adjacent magnets with different polarities are disposed partly facing to the shared ferromagnetism part 121 to the braking positions opposed to the respective magnets. COPYRIGHT: (C)2003,JPO

Hisayuki Takahashi

Papers

Eddy-current speed reducer