Lock-synchronisied gearbox shift system

Details Lock-synchronisied gearbox shift system Lock-synchronisied gearbox shift system

1996-01-22

1998-07-21

Lorence, Richard M.

192 clutches and power-stop control

Clutches

Progressive engagement

192 5333, 192 5334, 192 5335, 192 5351, 74339, F16D 2306

Patent

active

057823316

DESCRIPTION:

BRIEF SUMMARY
The invention concerns a transmission shift system with a lock synchronizing arrangement.


BACKGROUND OF THE INVENTION

For transmission of the driving power and adaptation of the engine torque to the required traction of a vehicle, multi-step gearshift transmissions are being practically exclusively used today.
The shift system can be considerably simplified by means of a synchronizing mechanism. In the synchronization, the torque adaptation of the transmission elements to be interconnected can be automatic or controlled in order to prevent double clutching when upshifting or double clutching with actuating the throttle when downshifting. The driving security is clearly increased, since quick, reliable and also noiseless gear changing is possible even in critical driving situations.
In the synchronized vehicle transmissions existing at present, synchronizing mechanisms are predominantly used for each individual gear.
The lock synchronization with taper adapter is widely propagated. In this system friction cones adapt to each other with positive engagement of the speeds of the transmission elements to be connected. This type of synchronization is used for transmissions both in passenger cars and in commercial vehicles.
Such a lock synchronization has been disclosed, for example, in "ZF-B-Sperr-synchronisierung"--publication 42290/R 2964-367 of March 1967.
The lock synchronization there described has a synchronizer ring provided with outer teeth which, when shifting, is pressed against the friction cone of the clutch member and turns until reaching detents on the synchronizer member in relation to a sliding sleeve. Thereby the chamfered tooth front surfaces of locking teeth of the synchronizer ring press against those of the sliding sleeve thus preventing further movement of the sliding sleeve. Only when the friction cone surfaces have produced the synchronous speed of the parts to be coupled, will the synchronizer ring be turned back under the constant pressure of the sliding sleeve through the facets of the teeth front faces. The lock is thus released and gearing teeth of the sliding sleeve are inserted in the teeth of the clutch member.
When idling, the sliding sleeve is in an axial central position. Springs compress the stop bolts in detents of the sliding sleeve. The idle wheels can freely rotate on their shafts. The speed difference between the synchronizer ring and the clutch member, and the drag torque between the friction surfaces thereof, causes the synchronizer ring to turn relative to the sliding sleeve and thus blocks a gear shift.
In a locking position, the sliding sleeve has first pushed the synchronizer ring toward the friction cone of the clutch member via the stop bolts and pressure pieces. The teeth front faces have thus passed the gearshift force from the sliding sleeve directly to the synchronizer ring. As long as a speed difference exists between the synchronizer ring and clutch member, the friction torque on the friction cone surfaces of the synchronizer ring and clutch member is stronger than the restoring torque through the chamfered teeth front faces. The sliding sleeve is therefore locked against extending into the clutch member.
Only when the speed difference between the synchronizer ring and clutch member has been equalized and the friction torque thus removed, does the sliding sleeve rotate the synchronizer ring back to the "tooth on tooth gap" position. The sliding sleeve is then inserted via the locking teeth of the synchronizer ring into the likewise front-side chamfered teeth of the clutch member.


SUMMARY OF THE INVENTION

Departing from this prior art, the problem to be solved by this invention is to obtain, with short shift strokes and slight shifting forces, a great locking security and an improved driving feel with a uniform shifting force cycle.
The problem is solved by transmission shift systems with lock synchronization having the claimed features.
The coupling teeth of the known synchronization mechanisms have facets which make the meshing operation possible. Sin

REFERENCES:
patent: 2394098 (1946-02-01), Peterson et al.
patent: 2753728 (1956-07-01), Kelbel
patent: 4271943 (1981-06-01), Kuzma
patent: 4770280 (1988-09-01), Frost

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