Power tool

A power tool, including:

• a motor that is housed within a tool body,
• a spindle that is rotatably disposed in a front end region of the tool body, and
• a speed changing mechanism that is disposed between an output shaft of the motor and the spindle and serves to change the rotational speed of the output shaft and transmit the rotational speed to the spindle, the speed changing mechanism including:
• first and second gear trains each having one set of a sun gear that is rotated by the output shaft, a planetary gear that engages with the sun gear and can revolve while rotating and an internal gear that engages with the planetary gear and can rotate on the sun gear, and
• a carrier that is connected to the spindle and rotatably supports the first planetary gear of the first gear train and the second planetary gear of the second gear tram, characterized in that:
• the power tool comprises a speed changing part that is slid in the longitudinal direction of the tool body by a user from the outside of the tool body, wherein:
• the speed changing part can move among first to third speed change positions, wherein, in the first speed change position, the speed changing part locks the first internal gear of the first gear train to the tool body and thus prevents the first internal gear from rotating, while allowing the second internal gear of the second gear train to rotate without locking the second internal gear to the tool body,
• in the second speed change position, the speed changing part locks the second internal gear to the tool body and thus prevents the second internal gear from rotating, while alb wing the first internal gear to rotate without locking the first internal gear to the tool body, and
• in the third speed change position, the speed changing part connects the first and second internal gears together and allows the first and second internal gears to rotate together without locking the first and second internal gears to the tool body,
• when the speed changing part is placed in the first speed change position, the carrier is rotated at a predetermined first speed which is defined by a speed reduction ratio of the first gear train,
• when the speed changing part is placed in the second speed change position, the carrier is rotated at a predetermined second speed which is defined by a speed reduction ratio of the second gear train and is faster than the first speed,
• when the speed changing part is placed in the third speed change position, the carrier is rotated together with the first and second sun gears at a predetermined third speed faster than the second speed, and
• the first speed change position is located on one end side in the sliding direction of the speed changing part, the second speed change position is located on the other end side, and the third speed change position is located in an intermediate position between the first and second speed change positions.