Robot joint structure

1. A robot joint structure comprising:

a first member and a second member that are hollow;

an actuator that rotates the second member about a rotation axis relative to the first member; and

a brake mechanism capable of braking rotation of the second member relative to the first member,

wherein the actuator includes a motor accommodated within the first member and not having a brake, a speed reducer that reduces the speed of rotation of a motor shaft of the motor and that transmits the rotation to the second member, a first gear provided at the motor shaft, and

a second gear provided in the speed reducer and engaged with the first gear, and

the brake mechanism includes a brake body accommodated within the first member, a brake shaft capable of being braked by the brake body, and a third gear provided at the brake shaft and engaged with the second gear,

wherein the first member includes a first section extending along the rotation axis, a second section extending in a direction intersecting the rotation axis, and a bent section provided between the first section and the second section, and,

in a bent space of the bent section, the motor is disposed along the rotation axis.

2. The robot joint structure according to claim 1 ,

wherein the speed reducer includes a hollow section including the rotation axis and extends through the speed reducer along the rotation axis,

the second gear is supported in a rotatable manner about the rotation axis and has a ring shape with a center hole, and

the first gear and the third gear are supported in a rotatable manner about axes that are parallel to the rotation axis and that are set apart from each other in a circumferential direction.