Drive system

Abstract

A drive system has a simple construction without a dedicated generator and permits improved energy efficiency in operating a motive power source in cooperation with an electric drive source. An output shaft of an engine is connected to a sun gear of a planetary gear assembly. An electric motor is connected, via gears, to a carrier rotatably supporting a planetary pinion gear that rotates around the outer circumference of the sun gear while rotating on its axis in engagement with the sun gear. An input shaft of a steptronic transmission is connected to a ring gear that rotates in engagement with the planetary pinion gear. The drive system further includes an engine clutch that directly couples the output shaft of the engine to the ring gear, a ring gear brake that regulates the rotation of the ring gear, and a torque converter clutch and a torque converter for transmitting the driving force of the electric motor to an output shaft of the steptronic transmission.

What is claimed is:  
     
         1 . A drive system comprising: 
 a motive power source;    an electric drive source serving as a generator and also as a motor;    a planetary gear mechanism; and    a transmission,    wherein the planetary gear mechanism comprises three rotary elements, namely, a sun gear rotating about the center of a central shaft, a carrier which rotatably supports a planetary pinion gear moving about the outer periphery of the sun gear while rotating on its axis in engagement with the sun gear and which rotates about the center of the central shaft, and a ring gear rotating about the center of the central shaft on the outer side of the planetary pinion gear while being meshed with the planetary pinion gear,    one of the three rotary elements of the planetary gear mechanism is connected to an output shaft of the motive power source,    another one of the rotary elements is connected to an input shaft of the transmission, and    the remaining one of the rotary elements is connected to an input/output shaft of the electric drive source.    
     
     
         2 . The drive system according to  claim 1 , comprising rotation regulating means for regulating the rotation of the rotary element connected to the input shaft of the transmission.  
     
     
         3 . The drive system according to  claim 1 , comprising motive power connecting/disconnecting means for switching connection and disconnection between the output shaft of the motive power source and the input shaft of the transmission.  
     
     
         4 . The drive system according to any one of  claims 1  to  3 , wherein 
 the transmission comprises a steptronic transmission having an input shaft provided with a train of input gears and an output shaft provided with a train of output gears meshing with the train of input gears, and  
 the drive system comprises driving force transmitting means provided between the input/output shaft of the electric drive source and the output shaft of the steptronic transmission for adjusting a driving force output from the electric drive source and transmitting the adjusted driving force to the output shaft of the steptronic transmission.  
 
     
     
         5 . The drive system according to  claim 4 , wherein the driving force transmitting means comprises a torque converter.  
     
     
         6 . The drive system according to any one of  claims 1  to  3 , wherein 
 the transmission comprises a steptronic transmission having an input shaft provided with a train of input gears and an output shaft provided with a train of output gears meshing with the train of input gears, and  
 the drive system comprises speed changing control means for controlling the rotational speed of the electric drive source such that the rotational speed of the input shaft of the steptronic transmission corresponds to the rotational speed obtained by multiplying the rotational speed of the output shaft of the steptronic transmission by a gear ratio of a new speed when performing speed change processing on the steptronic transmission.  
 
     
     
         7 . The drive system according to  claim 4 , comprising transmitted driving force control means for adjusting a driving force to be transmitted to the output shaft of the steptronic transmission from the input/output shaft of the electric drive source by the driving force transmitting means on the basis of the rotational speed of the output shaft of the steptronic transmission during the speed change processing performed in the steptronic transmission.  
     
     
         8 . The drive system according to  claim 1 , wherein 
 the drive system is mounted on a movable body, and comprises:    motive power source control means for controlling an output of the motive power source according to an instruction for a predetermined driving condition; and    electric drive source control means for controlling an output of the electric drive source so that an actual speed of the movable body follows a target speed of the movable body set according to the driving condition instruction.    
     
     
         9 . The drive system according to  claim 8 , comprising driving force managing means for determining an output of the motive power source according to a charged condition of storage means connected to the electric drive source.  
     
     
         10 . The drive system according to  claim 8  or  9 , wherein the electric drive source control means determines an output of the electric drive source by using response specifying control that permits variable designation of an attenuation behavior and an attenuation speed of a difference between the target speed and the actual speed of the movable body so as to make the actual speed of the movable body follow the target speed.  
     
     
         11 . The drive system according to  claim 8  or  9 , comprising: 
 braking means for braking the movable body; and  
 braking control means for determining a braking force of the braking means by using response specifying control that permits variable designation of an attenuation behavior and an attenuation speed of a difference between the target speed and the actual speed of the movable body so as to make the actual speed of the movable body follow the target speed.  
 
     
     
         12 . The drive system according to  claim 11 , wherein 
 the electric drive source control means determines an output of the electric drive source by using response specifying control that permits variable designation of an attenuation behavior and an attenuation speed of a difference between the target speed and the actual speed of the movable body so as to make the actual speed of the movable body follow the target speed, and    an attenuation speed of the difference between the target speed and the actual speed of the movable body in the response specifying control used by the electric drive source control means is set to be higher than an attenuation speed of the difference between the target speed and the actual speed of the movable body in the response specifying control used by the braking control means.