CLUTCH, BRAKE AND MOTOR CONTROLS FOR SYNCHRONIZED GEAR SHIFTING

• US 3,834,499 A
• Filed: 09/25/1972
• Issued: 09/10/1974
• Est. Priority Date: 09/25/1971
• Status: Expired due to Term

• Current Assignee: Giovanni Candellero, Stefano Aimo
• Original Assignee: Giovanni Candellero, Stefano Aimo
• Inventors: Candellero, Giovanni, Aimo, Stefano
• Primary Examiner(s): Wyche, Benjamin W.
• Application Number:
  US05/292,035
• Time in Patent Office: 715 Days
• Field of Search: 192/.033,.09,.092,4A,3.56,3.58 74/339,340
• US Class Current: 477/73
• CPC Class Codes: B60W 10/06 including control of combustion engines
• CPC Class Codes: B60W 10/11 Stepped gearings
• CPC Class Codes: B60W 2710/021 Clutch engagement state
• CPC Class Codes: B60W 2710/0605 Throttle position
• CPC Class Codes: B60W 2710/1005 Transmission ratio engaged
• CPC Class Codes: B60W 30/18 Propelling the vehicle
• CPC Class Codes: F16H 2003/123 using a brake
• CPC Class Codes: F16H 2061/0411 by control of shaft brakes
• CPC Class Codes: F16H 2061/305 Accumulators for fluid supply to the servo motors, or control thereof
• CPC Class Codes: F16H 3/12 with means for synchronisation not incorporated in the clutches
• CPC Class Codes: F16H 61/0403 Synchronisation before shifting
• CPC Class Codes: Y10T 74/19284 Meshing assisters
• CPC Class Codes: Y10T 74/19288 Double clutch and interposed transmission

Abstract

This invention provides an electronic gear synchronisation system for a motor vehicle gear box in which the input and output shaft speeds are recorded by respective transducers and the respective speed signals provided thereby are utilised in an electronic control unit to control the selective operation of accelerator means (e.g., the vehicle engine) and decelerator means (e.g., a shaft brake) acting on the gearbox input shaft so as to bring the ratio of the speeds of the input and output shafts into conformity with the preselected gear ratio, in a short time interval between disengagement of one pair of gears and engagement of another selected pair of gears.

Claims

1. A gear changing system for a motor vehicle comprising a synchromesh gear box having an input shaft connectable to the vehicle engine, a friction clutch for selectively connecting said input shaft into said vehicle engine, an output shaft shaft connectable to the driving wheels of the vehicle, pairs of selectively interchangable gears connecting the output shaft to the input shaft and manual selector means for preselecting a pair of gears for interengagement, said system further comprising accelerator and decelerator means for the engine, decelerator means for acting on said input shaft, gear acceleration clutch means operatively connecting said wheels and said output shaft, actuation means for engaging and disengaging the gears and said friction clutch, actuation means for controlling the accelerator and decelerator means and electrical circuits for controlling all of said actuator means, said electrical circuits including tachometric elements which are operatively associated with the power transmission from the engine to the gear box and with said output shaft, each of said tachometric elements being connected to respective frequency-amplitude conversion means and to means by which a ratio between the signals produced by said tachometric elements can be obtained, said ratio being equal to the value which corresponds to the transmission ratio of the selected pair of gear wheels, said electrical circuits also comprising first control means for the actuation means for engaging and disengaging the friction clutch, second control means for the actuation means for controlling the accelerator and decelerator means, third control means for the actuation means for engaging and disengaging the gears, correlation indicating means for indicating the state of engagement of said gears and said clutch activated by said actuation means and logic correlation circuits for controlling the electrical circuits for the control means whereby upon selective operation of said manual selector means said first control means will activate the actuation means for disengaging said friction clutch, said third control means will activate the actuation means for disengaging the originally engaged gears and said second control means will activate the actuation means for controlling the acceleration or deceleration means upon disengagement of said friction clutch when shifting up or down, said first control means activating the actuation means for engaging said friction clutch upon disengagement of said gears and said second control means activating the actuation means for the acceleration and deceleration means of the engine to obtain synchronization and upon synchronization said third control means activating the actuation means for engaging the preselected new gears and preventing further action of the second control means with respect to the actuation means for the accelerator and decelerator means for the engine, said second control means also controlling the activation of said gear acceleration means when shifting down during the continued activation of the actuation means or the accelerator means for the engine.

2. A gear changing system as set forth in claim 1 wherein said second control means is comprised of two summing circuits each having two inputs, one of which is connected directly to the output of the frequency-amplitude conversion means of one of said tachometric elements and the other of which is connected via an inverter to the output of the frequency-amplitude conversion means of the other of said tachometric elements, each of said summing circuits being connected to the logic correlation circuits through intermediate trigger circuits.

3. A gear changing system as set forth in claim 2 Further comprising interdiction means for said trigger circuit comprising a differential amplifier having inputs connected to each of frequency-amplitude conversion means and an output connected to said logic correlation circuits through additional trigger circuits.

4. A gear changing system as set forth in claim 1 wherein said gear box includes a normal ratio gear and a reduced ratio gear each adapted to be synchronously connected to said input shaft.