Traveling drive unit for working vehicle

A traveling drive unit for working vehicle, having a tubular wheel mounting case to be put in rotation integrally with a wheel for working vehicle, a reduction gear mechanism provided in said wheel mounting case and adapted to reduce rotational speed in transmitting rotation of a drive source to said wheel mounting case, and a lubricant oil circulation means for supplying lubricant oil to said reduction gear mechanism, characterized in that;

• said lubricant oil circulation means is comprised of an electric motor, a lubricant circulation pump which is rotationally driven by said electric motor to forcibly circulate lubricant oil pooled in said wheel mounting case, and a motor control means adapted to turn on and turn off said electric motor according to detected temperature by a temperature sensor for detecting temperature of said lubricant oil and detected speed by a speed sensor for detecting rotational speed of said wheel;
• said motor control means is adapted to turn on said electric motor when a temperature of lubricant oil detected by said temperature sensor is higher than a predetermined reference temperature and a speed of said wheel detected by said speed sensor is lower than a predetermined reference speed;
• and
• said motor control means is adapted to turn off said electric motor when said detected temperature is lower than said reference temperature or said detected speed is higher than said reference speed.