Lubricant oil state warning device for a working vehicle

A travel drive apparatus for a working vehicle, comprising:

• a tubular wheel mounting case provided on a working vehicle and rotating integrally with a wheel;
• a reduction gear mechanism provided in said wheel mounting case to reduce the speed of rotation of a drive source and transmit it to said wheel mounting case;
• lubricant oil circulation means for supplying a lubricant oil to said reduction gear mechanism;
• a temperature sensor for detecting a temperature (T) of said lubricant oil;
• and
• a speed sensor for detecting a rotational speed (V) of said wheel, characterized in that;
• said lubricant oil circulation means being constituted by an electric motor, a lubricant pump for forcibly circulating the lubricant oil pooled in said wheel mounting case by being driven by said electric motor, and control means for controlling the drive and stop of said electric motor in accordance with the rotational speed (V) of said wheel,
• said control means comprising:
• motor stop means for stopping the drive of said electric motor when the speed (V) of said wheel detected by said speed sensor has become faster than a predetermined determination speed (V1);
• temperature difference determination means for comparing the temperature (T) of said lubricant oil detected by said temperature sensor and a predetermined warning temperature (Toh) and determining whether or not a temperature difference (ΔT) between them is within a range of a predetermined threshold value (α, β) when said electric motor is stopped by said motor stop means;
• and
• warning signal output means for outputting a signal for warning that a temperature state of said lubricant oil or a traveling state is not normal, when it is determined by said temperature difference determination means that said temperature difference (ΔT) is within the range of the threshold value (α, β).