Crawler-type work machine

A crawler-type work machine comprising:

• left and right planetary gear mechanisms disposed between an input shaft and left and right output shafts;
• left and right steering clutches configured to rotate about the input shaft and switch between transmitting and blocking rotational power from the input shaft to the left and right output shafts using the left and right planetary gear mechanisms;
• left and right steering brakes configured to brake the left and right output shafts;
• a turning motor configured to cause the left and right steering clutches to rotate so that a rotation speed difference is produced between the left and right output shafts;
• a controller configured to control the left and right steering clutches, the left and right steering brakes, and the turning motor to cause the crawler-type work machine to travel in a straight travel mode, a slow turning mode, or a pivot turning mode,
• in the straight travel mode, the controller being configured to cause the left and right steering clutches to engage, cause the left and right steering brakes to disengage, and stop the turning motor;
• in the slow turning mode, the controller being configured to cause the left and right steering clutches to engage, cause the left and right steering brakes to disengage, and drive the turning motor;
• in the pivot turning mode, the controller being configured to cause an inside steering clutch corresponding to a steering direction of the left and right steering clutches to disengage, and cause an inside steering brake corresponding to the steering direction of the left and right steering brakes to brake, and drive the turning motor;
• and
• when switching from the pivot turning mode to the straight travel mode or the slow turning mode, the controller being configured to maintain a rotation speed of the turning motor until after a first timing at which the inside steering clutch begins partial engagement.