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 be able 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 by means of the left and right planetary gear mechanisms;
• left and right steering brakes configured to respectively 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 steering lever configured to be operated in a left turning direction and a right turning direction using a neutral position as a point of reference;
• and
• a controller configured to control the left and right steering clutches, the left and right steering brakes, and the turning motor in response to an operating direction and an operating amount of the steering lever,
• the controller being further configured to
• cause the left and right steering clutches to engage, cause the left and right steering brakes to release, and drive the turning motor so that, among the left and right output shafts, the rotation speed of an inside output shaft corresponding to the operating direction becomes lower than the rotation speed of an outside output shaft opposite to the operating direction as the operating amount increases when the operating amount is greater than a first predetermined amount and a quick turn instruction has not been received from an operator;
• and
• reduce an engagement rate of the inside steering clutch corresponding to the operating direction among the left and right steering clutches and cause the inside steering brake corresponding to the operating direction among the left and right steering brakes to brake while continuously driving the turning motor, when the operating amount is greater than the first predetermined amount and the quick turn instruction has been received.