Lubrication control apparatus for vehicle in-wheel motor unit

Abstract

Each oil pump ( 32 ) is drivingly controlled in such a way that, in a low vehicle speed region lower than a set vehicle speed VSP 1 at which a stirring resistance by oil within an in-wheel unit case ( 3 ) is not in excess of an allowance level, a suction and supply quantity denoted by a solid line characteristic is provided. In other words, the oil pump(s) is stopped until the vehicle speed reaches to a predetermined vehicle speed VSP 0 at which a remaining oil within an oil passage is scattered in all directions and becomes disappeared after the start of vehicle in an oil pump stopped state including a vehicle stop at which the lubrication is not necessary.

1 . A lubrication control apparatus for in-wheel motor units for use in an in-wheel motor driven vehicle in which road wheels are driven by means of the individual in-wheel motor units in order for the vehicle to be travelable and in which individual oil pumps lubricate within the in-wheel motor units through oil sucked and supplied from lower parts of respective in-wheel motor unit cases, the lubrication control apparatus comprising: oil pump driving control means for drivingly controlling the oil pumps to stop the oil pumps when the vehicle is in a vehicle stopped state and to activate the oil pumps when a vehicle speed has reached to a predetermined vehicle speed. 
     
     
         2 . The lubrication control apparatus for the in-wheel motor units for use in the in-wheel motor driven vehicle as claimed in  claim 1 , wherein the predetermined vehicle speed to activate the oil pumps is a vehicle speed at which a remaining oil in an oil suction and supply passage to suck and supply oil is scattered in all directions and becomes disappeared. 
     
     
         3 . The lubrication control apparatus for the in-wheel motor units for use in the in-wheel motor driven vehicle as claimed in  claim 1 , wherein the oil pump driving control means sets the predetermined vehicle speed in accordance with a traveling distance of the vehicle in the oil pump stopped state. 
     
     
         4 . The lubrication control apparatus for the in-wheel motor units for use in the in-wheel motor driven vehicle as claimed in  claim 3 , wherein the oil pump driving control means determines the vehicle traveling distance in the oil pump stopped state by an integration of the vehicle speed with respect to time during a travel in the oil pump stopped state to contribute on the setting of the predetermined vehicle speed. 
     
     
         5 . The lubrication control apparatus for the in-wheel motor units for use in the in-wheel motor driven vehicle as claimed in  claim 1 , wherein the oil pump driving control means drivingly controls the oil pumps such that oil suction and supply quantities from the oil pumps are gradually increased as the vehicle speed is increased in a low vehicle speed region which is lower than a set vehicle speed at which a stirring resistance of oil at each of the lower parts within the in-wheel motor unit cases does not exceed an allowance level after the vehicle speed has reached to the predetermined vehicle speed. 
     
     
         6 . The lubrication control apparatus for the in-wheel motor units for use in the in-wheel motor driven vehicle as claimed in  claim 5 , wherein the in-wheel motor driven vehicle is travelable by driving at least pair of right and left road wheels through the individual in-wheel motor units and the oil pump driving control means drivingly controls the oil pumps such that the oil suction and supply quantities when the vehicle speed is increased and reached to the set vehicle speed are predetermined quantities at which oil levels at the lower parts within the respective cases of the in-wheel motor units which provide the pair of left and right in-wheel motor units are mutually the same. 
     
     
         7 . The lubrication control apparatus for the in-wheel motor units for use in the in-wheel motor driven vehicle as claimed in  claim 6 , wherein the oil pump driving control means drivingly controls the oil pumps such that each of the oil suction and supply quantities from the oil pumps is maintained at a predetermined quantity in a high vehicle speed region of the vehicle speed equal to or higher than the set vehicle speed. 
     
     
         8 . The lubrication control apparatus for the in-wheel motor units for use in the in-wheel motor driven vehicle as claimed in  claim 6 , wherein the predetermined quantity related to each of the oil suction and supply quantities is a minimum oil quantity required for the lubrication within each of the in-wheel motor units. 
     
     
         9 . The lubrication control apparatus for the in-wheel motor units for use in the in-wheel motor driven vehicle as claimed in  claim 1 , wherein the oil pump driving control means drivingly controls the oil pumps to activate the oil pumps under a condition such that the vehicle speed is raised to the predetermined vehicle speed at which a remaining oil in an oil suction and supply passage to suck and supply oil is scattered in all directions and becomes disappeared after the travel start of the vehicle and drivingly controls the oil pumps to activate the oil pumps from a vehicle speed lower than the predetermined vehicle speed including the stop of the vehicle in accordance with a demanded driving torque of the vehicle. 
     
     
         10 . The lubrication control apparatus for the in-wheel motor units for use in the in-wheel motor driven vehicle as claimed in  claim 1 , wherein the oil pump driving control means activates the oil pumps when the vehicle speed has reached to the predetermined vehicle speed after the start of traveling of the vehicle and drivingly controls the oil pumps such that the oil pumps are activated at a lower vehicle speed than the predetermined vehicle speed.