Hydro-mechanical threshing rotor control system for an agricultural combine

Abstract

A hydro-mechanical control system for an agricultural combine threshing rotor is operable 1) to transfer torque to the rotor so as to maintain rotor velocity within an acceptable range of a commanded velocity despite small fluctuations in rotor load and engine speed, 2) to reduce wear on mechanical components of the rotor drive system during rotor acceleration, 3) to employ the most efficient combination of mechanical and hydrostatic rotor drive characteristics during steady state operation of the rotor and 4) to reduce the likelihood of engine stall. The system includes a mechanical motor such as an engine, a hydrostatic motor, and a gearset disposed between both motors and the rotor. A clutch is operable to selectively couple the mechanical motor to the gearset, and a brake is selective operable to selectively arrest a driven gear of the gearset from rotation.

1 . A method of driving a threshing rotor of an agricultural combine, comprising: 
 (A) coupling a hydrostatic motor to said rotor and driving said rotor to accelerate from a prevailing velocity to at least generally a commanded rotational velocity; and    (B) coupling a mechanical motor to said rotor when a conditional threshold is reached.    
   
   
       2 . The method as recited in  claim 1 , wherein said motors are selectively coupled to said rotor via a common gearset, and further comprising controlling operation of said gearset to selectively couple said mechanical motor and/or said hydrostatic motor to said rotor via the gearbox.  
   
   
       3 . The method as recited in  claim 2 , wherein 
 during acceleration of said rotor from rest, the step (A) comprises coupling only said hydrostatic motor to said rotor while leaving said mechanical motor uncoupled from said rotor, and the step (B) comprises initiating coupling of said mechanical motor to said rotor when a conditional threshold is reached and then modulating operation of said hydrostatic motor to maintain the rotor velocity at least substantially at the commanded rotor velocity.    
   
   
       4 . The method as recited in  claim 3 , further comprising selecting one of a plurality of desired rotor speed ranges by operation of a multi-speed gearbox located between said gearset and said rotor, and wherein said commanded rotor velocity varies with the selected rotor speed range.  
   
   
       5 . The method as recited in  claim 2 , further comprising modulating operation of said hydrostatic motor in response to detected changes in rotor velocity when said hydrostatic motor and said mechanical motor are both coupled to said rotor.  
   
   
       6 . The method as recited in  claim 5 , wherein the modulating step comprises increasing an output speed of said hydrostatic motor at least generally proportionally with a difference between an actual rotor velocity and the commanded rotor velocity.  
   
   
       7 . The method as recited in  claim 2 , wherein the step of controlling operation of said gearset comprises releasing a ring-to-frame brake and engaging a mechanical motor-to-ring clutch to couple said mechanical motor to said rotor.  
   
   
       8 . The method as recited in  claim 7 , wherein the step of controlling operation of said gearset comprises releasing said clutch and engaging said brake during initial acceleration of said rotor from rest and releasing said brake and engaging said clutch during steady state operation of said rotor.  
   
   
       9 . The method as recited in  claim 2 , further comprising uncoupling said mechanical motor from said rotor, and deslugging said rotor by controlling operation of said hydrostatic motor so as to unjam said rotor.  
   
   
       10 . The method as recited in  claim 9 , wherein the controlling step comprises manually operating said controller to alternatively and repeatedly run said hydrostatic motor in forward and reverse directions and displaying rotor velocity during deslugging.  
   
   
       11 . A method of accelerating a threshing rotor of an agricultural combine from rest, comprising: 
 (A) coupling a hydrostatic motor to said rotor and driving said rotor to accelerate said rotor while leaving a mechanical motor uncoupled from said rotor; and    (B) when said rotor at least approaches a commanded velocity, coupling a mechanical motor to said rotor while leaving said hydrostatic motor coupled to said rotor.    
   
   
       12 . A method of controlling steady-state operation of a threshing rotor of a harvesting machine, the method comprising: 
 (A) coupling a mechanical motor and a hydrostatic motor to said rotor via a common gearset; and    (B) monitoring the rotational velocity of said rotor; and    (C) controlling said hydrostatic motor to accelerate or decelerate said rotor as required to maintain rotor velocity within a designated range of a commanded rotor velocity.    
   
   
       13 . The method as recited in  claim 12 , wherein the step (C) comprises increasing fluid flow to said hydrostatic motor if the actual velocity of said rotor is below said range and decreasing fluid flow if the actual velocity of said rotor is above said range.  
   
   
       14 . The method as recited in  claim 12 , 
 wherein the step (A) comprises engaging a mechanical motor-to-ring clutch to couple a ring of said gearset to said mechanical motor, and releasing a ring-to-frame brake that brakes said ring from rotation.    
   
   
       15 . A threshing rotor drive system, comprising: 
 (A) an agricultural threshing rotor;    (B) a mechanical motor;    (C) a hydrostatic motor;    (D) a gearset located between said motors and said rotor; and    (E) a control system that controls said gearset so as to at least selectively couple at least one of said motors to said rotor, said control system being dimensioned and configured to couple said hydrostatic motor to said rotor and to control said hydrostatic motor to drive said rotor to accelerate from a prevailing velocity to at least generally a commanded rotational velocity.    
   
   
       16 . The drive system as recited in  claim 15 , further comprising a multi-speed gearbox coupling said gearset to said rotor, said gearbox being settable to select one of a plurality of rotor speed ranges.  
   
   
       17 . The drive system as recited in  claim 15 , wherein said gearset includes a sun gear coupled to said hydrostatic motor, a plurality of planet gears coupled to said rotor, and a ring gear operatively coupled to said planet gears, and further comprising a clutch that is responsive to said controller to selectively couple said mechanical motor to said ring gear and a brake that is responsive to said controller to selectively arrest said ring gear from rotation.  
   
   
       18 . The drive system as recited in  claim 15 , wherein said mechanical motor comprises an engine of a harvesting machine incorporating said rotor.  
   
   
       19 . The drive system as recited in  claim 18 , further comprising a variable output pump which drives said hydrostatic motor and which is driven by said engine.  
   
   
       20 . A method of permitting an agricultural harvesting implement operator to send rotor speed commands and receive readout of system parameters.  
   
   
       21 . A method of accelerating to and maintaining rotor velocity at a predetermined commanded velocity from rest, comprising: 
 sequentially accelerating the rotor hydrostatically, using a hydrostatic drive path that includes a pump and a motor, then further controlling rotor acceleration by control of a clutch, a brake and a pump valve coil current, thereby accelerating the rotor to the commanded velocity, then, once the commanded velocity has been achieved, maintaining at least essentially constant velocity by using a mechanical drive path for primary power and the hydrostatic path only to adjust rotor velocity as required to maintain the rotor velocity at at least essentially the commanded velocity.