Method of decelerating a power shift transmission

• US 4,989,470 A
• Filed: 05/10/1990
• Issued: 02/05/1991
• Est. Priority Date: 12/01/1989
• Status: Expired due to Fees

• Current Assignee: Blue Leaf IP Incorporated (CNH Industrial N.V.)
• Original Assignee: Ford New Holland, Inc.
• Inventors: Bulgrien, Garth H.
• Primary Examiner(s): Wright, Dirk
• Application Number:
  US07/521,629
• Time in Patent Office: 271 Days
• Field of Search: 74/335, 74/866, 364/424.1
• US Class Current: 74/335
• CPC Class Codes: B60W 10/02 including control of driveline clutches
• CPC Class Codes: B60W 10/11 Stepped gearings
• CPC Class Codes: B60W 2510/104 Output speed
• CPC Class Codes: B60W 2540/14 Clutch pedal position
• CPC Class Codes: B60W 2540/16 Ratio selector position
• CPC Class Codes: B60W 2710/021 Clutch engagement state
• CPC Class Codes: B60W 2710/1005 Transmission ratio engaged
• CPC Class Codes: B60W 30/18045 Rocking, i.e. fast change between forward and reverse
• CPC Class Codes: F16H 2059/006 Overriding automatic control
• CPC Class Codes: F16H 2059/0239 Up- and down-shift or range or mode selection by repeated movement mechanical step by step selection devices F16H63/14
• CPC Class Codes: F16H 2059/088 Fast forward-reverse-sequence mode
• CPC Class Codes: F16H 2059/6807 Status of gear-change operation, e.g. clutch fully engaged
• CPC Class Codes: F16H 2061/0087 Adaptive control, e.g. the control parameters adapted by learning
• CPC Class Codes: F16H 2061/0216 Calculation or estimation of post shift values for different gear ratios, e.g. by using engine performance tables
• CPC Class Codes: F16H 2312/00 Driving activities
• CPC Class Codes: F16H 2312/02 Driving off
• CPC Class Codes: F16H 2312/022 Preparing to drive off
• CPC Class Codes: F16H 2312/08 Rocking
• CPC Class Codes: F16H 2342/042 Point of engagement
• CPC Class Codes: F16H 59/42 Input shaft speed
• CPC Class Codes: F16H 59/46 : dependent on a comparison between speeds
• CPC Class Codes: F16H 59/56 : dependent on signals from the main clutch
• CPC Class Codes: F16H 61/0059 : Braking of gear output shaft using simultaneous engagement of friction devices applied for different gear ratios
• CPC Class Codes: F16H 61/0213 : characterised by the method for generating shift signals
• CPC Class Codes: F16H 61/0246 : characterised by initiating reverse gearshift
• CPC Class Codes: F16H 61/0248 : Control units where shifting is directly initiated by the driver, e.g. semi-automatic transmissions generation of movements for final actuating mechanisms F16H61/28
• CPC Class Codes: F16H 61/682 : with interruption of drive
• CPC Class Codes: F16H 61/684 : without interruption of drive
• CPC Class Codes: F16H 61/70 : specially adapted for change-speed gearing in group arrangement, i.e. with separate change-speed gear trains arranged in series, e.g. range or overdrive-type gearing arrangements
• CPC Class Codes: F16H 63/42 : Ratio indicator devices
• CPC Class Codes: F16H 63/46 : Signals to a clutch outside the gearbox
• CPC Class Codes: Y10T 74/19251 : Control mechanism

Abstract

A microprocessor controlling a shuttle shift transmission may be programmed while the gearshift lever is in neutral to preselect a forward and reverse gear into which the transmission is shifted when the gearshift lever is moved to a forward or reverse position. The microprocessor may also be programmed so that, in shifting between forward and reverse, the forward and reverse gears selected differ by a pre-programmed amount. The microprocessor may be programmed to control vehicle deceleration by selecting gears in the transmission so that the transmission and/or the vehicle engine become a load for decelerating the vehicle. In the method of decelerating the tractor from relatively high vehicle speeds, the transmission is disconnected from the engine and then locked by simultaneously engaging two clutches for the simultaneous engagement of two gear ratios. A modulation of the final clutch set permits the inertial energy of the tractor to be dissipated.

Claims

1. A method of controlling vehicle deceleration during shuttle shifting of a transmission having an initial clutch set for selectively connecting an engine driven input drive shaft in driving relationship with a first plurality of shafts, a final clutch set for selectively connecting a second plurality of shafts in driving relationship with an output shaft for driving the vehicle, and an intermediate clutch set for selectively connecting the first plurality of shafts in driving relationship with said second plurality of shafts, first gears on said first plurality of shafts for driving all of said first plurality of shafts at the same speed when any clutch of said initial clutch set is energized, and second gears on said first plurality of shafts for driving said second plurality of shafts at different speeds relative to the speeds of said first plurality of shafts when any one clutch of said set of intermediate clutches is energized, said method comprising:

releasing all clutches in said initial set of clutches to disconnect the transmission from the engine;

energizing at least two clutches in said intermediate set of clutches to lock the transmission;

energizing at least one of the clutches in the final set of clutches;

sensing the vehicle speed, and,

when the vehicle speed approaches zero, selectively energizing one clutch in each of said clutch sets to select the speed at which the output shaft will be driven.

2. A method as claimed in claim 1 wherein vehicle speed is sensed by sensing rotation of the output shaft.

11. The method of claim 1 further comprising the steps of:

sensing vehicle speed; and

when said vehicle speed has reached a desired value, releasing all clutches in said intermediate clutch set necessary to unlock said transmission; and

then, selecting a gear ratio by energizing a selective clutch in each of said initial clutch set, said intermediate clutch set, and said final clutch set to select a desired speed of operation corresponding to the desired vehicle speed.

12. The method of claim 11 wherein said sensing step includes:

monitoring the speed of rotation of said output shaft.

14. The method of claim 11 wherein said selecting step effects operation of said vehicle in a direction opposite to the direction of operation of said vehicle prior to said energizing step.

3. A method of controlling vehicle deceleration during shuttle shifting of a power shift transmission having clutches for selectively interconnecting an input drive shaft, an output drive shaft, and a plurality of gears rotatably housed in said transmission in driving relationship with said input and output drive shafts such that a selective engagement of said clutches will effect a varying of the speed of operation of said output shaft for a given speed of operation of said input shaft, said gears being arranged in preselected gear ratios from a low speed to a high speed, the method comprising:

disconnecting said transmission from said input shaft;

locking said transmission to prevent rotation of said gears; and

modulating at least one of said clutches to decelerate the speed of movement of said vehicle to a desired speed of operation by dissipating the inertial energy of said vehicle through said at least one clutch.

4. The method of claim 3 wherein said clutches include an initial clutch set having a plurality of clutches therein for selectively connecting said input drive shaft in driving relationship with a first plurality of shafts and a corresponding set of drivingly engaged first gears and a final clutch set having a plurality of clutches therein for selectively connecting a second plurality of shafts and a corresponding set of drivingly engaged second gears in driving relationship with said output shaft for driving the vehicle, said disconnecting step including the step of:

releasing all clutches in said initial clutch set to disconnect said input drive shaft from said first plurality of shafts.

5. The method of claim 4 wherein said modulating step includes the step of:

engaging at least one of said clutches in said final clutch set to dissipate the inertial energy of said vehicle transmitted through said output shaft.

6. The method of claim 5 wherein said clutches further include an intermediate clutch set for selectively connecting the first plurality of shafts and said first set of gears in driving relationship with said second plurality of shafts and said second set of gears, said locking step including the step of:

engaging at least two of the clutches in said intermediate clutch set, thereby preventing rotation of said first and second plurality of shafts.

7. The method of claim 3 further comprising the steps of:

sensing vehicle speed; and

when said vehicle speed has reached a desired value, unlocking said transmission to permit normal operation thereof; and

then selecting a gear having the desired gear ratio by selectively engaging appropriate clutches.

8. The method of claim 7 wherein said sensing step includes the step of:

monitoring the speed of rotation of said output shaft.

9. The method of claim 8 wherein said selecting step effects operation of said vehicle in a direction opposite to the direction of operation of said vehicle prior to said disconnecting step.

10. A method of controlling vehicle deceleration during shuttle shifting of a transmission having an initial clutch set for selectively connecting an engine driven input drive shaft in driving relationship with a first plurality of shafts, a final clutch set for selectively connecting a second plurality of shafts in driving relationship with an output shaft for driving the vehicle, and an intermediate clutch set for selectively connecting the first plurality of shafts in driving relationship with said second plurality of shafts, first gears on said first plurality of shafts for driving all of said first plurality of shafts at the same speed when any clutch of said initial clutch set is energized, and second gears on said first plurality of shafts for driving said second plurality of shafts at different speeds relative to the speeds of said first plurality of shafts when any one clutch of said set of intermediate clutches is energized, said method comprising:

releasing all clutches in said initial clutch set to prevent the transfer of rotational power from said input drive shaft to said first plurality of shafts;

energizing at least two clutches in said intermediate clutch set to lock said transmission so that said first and second plurality of shafts cannot transfer rotational power and said first and second gears cannot rotate; and

modulating at least one clutch in said final clutch set to decelerate the rotational speed of said output shaft and, therefore, the speed of movement of said vehicle.

13. The method of claim 10 wherein said modulating step dissipates the inertial energy of said vehicle to effect deceleration thereof.