Compact actuator arrangement

An actuator comprising:

• a motor comprising a housing and a drive shaft, the motor arranged to rotate the drive shaft relative to the housing about a drive shaft axis;
• a first torque transfer device comprising a first drive member on the drive shaft and a first driven member on a second shaft, the first drive member being arranged to transfer torque to the first driven member, such that the first torque transfer device is arranged to transfer torque from the drive shaft to the second shaft, the second shaft being rotatable about a second shaft axis spaced from the drive shaft axis;
• an output torque transfer device comprising an output drive member on the second shaft and an output driven member, the output drive member being arranged to transfer torque to the output driven member, such that the output driven member rotates about an output axis;
• a first connection flange fixed to the motor housing at an axial end of the motor housing opposite to the end of the motor housing where the drive shaft extends;
• and
• a second connection flange arranged such that the drive shaft is between the second connection flange and the motor housing, the second connection flange being fixed to the motor housing via a cross member,
• wherein (a) the motor housing is arranged at least partially inside the output driven member or (b) the output driven member is fixed to the motor housing.

A robotic joint comprising:

• a first member;
• a second member pivotably coupled to the first member;
• and
• an actuator comprising:
• a motor comprising a housing and a drive shaft, the motor arranged to rotate the drive shaft relative to the housing about a drive shaft axis;
• a first torque transfer device comprising a first drive member on the drive shaft and a first driven member on a second shaft, the first drive member being arranged to transfer torque to the first driven member, such that the first torque transfer device is arranged to transfer torque from the drive shaft to the second shaft, the second shaft being rotatable about a second shaft axis spaced from the drive shaft axis;
• and
• an output torque transfer device comprising an output drive member on the second shaft and an output driven member, the output drive member being arranged to transfer torque to the output driven member, such that the output driven member rotates about an output axis,
• wherein the actuator is arranged to rotate the first member relative to the second member, wherein the motor is coupled to the second member, and wherein the second shaft is supported by the first member, and
• wherein the first member is arranged to pivot relative to the second member about the drive shaft axis.