An actuator with switchable releasing speed includes an actuation rod, a screw, and a motor. The motor drives the screw rotating so that the actuation rod axially moves relative to the screw. The motor includes a stator, a rotor, a plurality of commutators, and at least three brushes. The at least three brushes have a positive brush, a negative brush, and at least one auxiliary brush. The positive brush is connected to a positive DC voltage. One of the negative brush and the least one auxiliary brush is adjusted to connect to a negative DC voltage so as to change a rotational speed of the rotor, thereby controlling a movement speed of the actuation rod. Accordingly, the releasing speed of the actuator is switchable.

An actuator with switchable releasing speed includes an actuation rod, a screw, and a motor. The motor drives the screw rotating so that the actuation rod axially moves relative to the screw. The motor includes a stator, a rotor, a plurality of commutators, and at least three brushes. The at least three brushes have a positive brush, a negative brush, and at least one auxiliary brush. The positive brush is connected to a positive DC voltage. One of the negative brush and the least one auxiliary brush is adjusted to connect to a negative DC voltage so as to change a rotational speed of the rotor, thereby controlling a movement speed of the actuation rod. Accordingly, the releasing speed of the actuator is switchable.

An actuator with switchable releasing speed includes an actuation rod, a screw, and a motor. The motor drives the screw rotating so that the actuation rod axially moves relative to the screw. The motor includes a stator, a rotor, a plurality of commutators, and at least three brushes. The at least three brushes have a positive brush, a negative brush, and at least one auxiliary brush. The positive brush is connected to a positive DC voltage. One of the negative brush and the least one auxiliary brush is adjusted to connect to a negative DC voltage so as to change a rotational speed of the rotor, thereby controlling a movement speed of the actuation rod. Accordingly, the releasing speed of the actuator is switchable.

A communicating hole, which communicates between a clearance space and the outside of a cover member, is formed in the cover member, and a seal cap is fitted to and retained in a distal-end opening of the communicating hole. The seal cap includes a cap main body having a ventilation through hole formed in an internal axial direction and an outer peripheral wall configured to engage with the communicating hole, a supporting portion fitted, from the outside, into a recessed groove formed in an outside end face of the cap main body, and a ventilation filter located on a bottom face of the recessed groove and retained and sandwiched between the cap main body and the supporting portion. Therefore, an internal pressure rise in the clearance space between the cover member and an electric motor can be effectively suppressed, and thus improved mountability and retainability can be obtained.