Torque restriction mechanism, drive device, and robot device
AssigneeMitsubishi Electric Corporation
InventorAkiko Hamada
Life of this patent
Estimating the term…
Abstract
A torque restriction mechanism is provided by which torque cutoff and torque transmission can be reliably performed without being affected by a rotation state of the drive unit, and damage to a collision object can be reduced even with a simple configuration. The torque restriction mechanism includes a first clutch and a second clutch. The first clutch cuts off torque to a driven unit when reaction torque at a stationary portion of a motor equals or exceeds a first value. The second clutch that transmits torque in accordance with a rotation state of a rotor of the motor, cuts off torque to the driven unit when the reaction torque equals or exceeds a second value larger than the first value.
Claims19
A torque restriction mechanism to be connected to a housing and a stationary portion that includes a stator of a motor for rotating a driven unit with respect to the housing of a drive device for housing the motor, and to transmit or cut off torque from the housing to the stationary portion, the torque restriction mechanism comprising:
- a first clutch to cut off the torque to the driven unit when reaction torque generated in the stationary portion due to rotation of the driven unit equals or exceeds a predetermined first value;
- and
- a second clutch to transmit the torque based on a rotation state of a rotor of the motor to be connected to the driven unit,
- wherein the second clutch cuts off the torque to the driven unit when the reaction torque equals or exceeds a second value larger than the first value.
A drive device comprising:
- an electric motor that includes a stator and a rotating rotor;
- a housing that houses the electric motor and that transfers torque generated by the electric motor;
- a magnetic clutch that magnetically attaches the electric motor to the housing, the magnetic clutch disengages the electric motor from the housing in response to receiving a reaction torque greater than the magnetic force holding the electric motor to the housing;
- a locking clutch that attaches the electric motor to the housing, the locking clutch includes an actuator that engages the locking clutch with the electric motor to enable and disable torque control by the locking clutch, the locking clutch disengages the electric motor from the housing in response to receiving a reaction torque that exceeds a locking force holding the actuator of the locking clutch to the electric motor;
- a controller configured to control the electric motor, compute an angular acceleration of the electric motor based on the control of the electric motor, and operate the actuator of the locking clutch to enable the locking clutch in response to determining that the angular acceleration of the electric motor is equal to, or greater than, a predetermined threshold, wherein
- the magnetic clutch and the locking clutch are configured to disengage the electric motor from the housing without receiving a command from the controller to disengage the housing.
A drive device comprising:
- an electric motor that includes a stator and a rotating rotor;
- a housing that houses the electric motor and that includes an electric motor fixing plate attached to the electric motor and a sliding plate that supports the electric motor fixing plate, the housing transfers torque generated via the rotating rotor of the electric motor;
- a magnetic clutch magnetically attached between the housing and the electric motor fixing plate to transfer torque from the electric motor to the housing, the magnetic clutch disengages the electric motor fixing plate from the housing in response to a reaction torque greater than a magnetic force holding the electric motor fixing plate to the housing to release the housing from the rotating rotor and allow the electric motor to freely rotate on the sliding plate without transferring torque to the housing;
- a torque cutoff detection sensor that outputs a torque cutoff signal in response to the magnetic clutch disengaging the electric motor fixing plate from the housing;
- a locking clutch attached to the housing that engages with the electric motor fixing plate to enable torque transfer from the electric motor to the housing, the locking clutch includes an actuator that enables and disables torque control by the locking clutch;
- and
- a controller electrically connected to the electric motor, the torque cutoff detection sensor, and the actuator of the locking clutch, the controller is configured to
- control the rotating rotor,
- determine an angular acceleration of the electric motor based on the control of the rotating rotor,
- operate the actuator of the locking clutch to enable torque control by the locking clutch in response to determining that the angular acceleration of the electric motor is equal to, or greater than, a predetermined threshold, and
- stop current supply to the rotating rotor in response to receiving the torque cutoff detection signal from the torque cutoff detection sensor.
Dependencies are inferred from the claim text.