192 clutches and power-stop control – Clutches – Plural clutch-assemblage
Reexamination Certificate
1999-10-22
2001-03-27
Bonck, Rodney H. (Department: 3681)
192 clutches and power-stop control
Clutches
Plural clutch-assemblage
C192S052500, C192S054300, C192S054510, C192S085060, C192S083000, C192S04100R
Reexamination Certificate
active
06206161
ABSTRACT:
TECHNICAL FIELD
This invention relates to torque transmitting mechanisms for automatically shifting power transmissions and more particularly to such transmissions having a one-way torque transmitting mechanism.
BACKGROUND OF THE INVENTION
Many of the currently available passenger vehicles have automatically shifting transmissions to provide a plurality of discrete gear ratios between the engine and the drive wheels. Most of these transmissions employ at least one directional sensitive torque transmitting mechanism or one-way drive mechanism to accommodate a smooth ratio interchange. Generally this interchange occurs between the first forward ratio and the second forward ratio. The more premium of the automatic shifting transmissions utilize more than one direction sensitive torque transmitting mechanism.
These transmission mechanisms also have a positive torque transmitter in parallel with the direction sensitive mechanism to accommodate engine coast braking. For example, when negotiating a steep grade, it is desirable to manually engage one of the lower drive ratios such as low gear or second gear. If this ratio is established, during normal driving, by a one-way device, it becomes necessary to also include a selectively engageable friction torque transmitter, such as a clutch or brake, to enforce engine coast braking which will augment or perhaps supersede any necessary vehicle service brake application.
The direction sensitive torque transmitters most often found in the automotive vehicle transmission are of the roller or sprag variety. These one-way mechanisms of course add cost to the transmission. The friction torque transmitter used in parallel with these one-way devices is generally a multi-plate fluid operated mechanism. In many design configurations, the one-way device is located radially inward of a portion of the friction mechanism resulting in the friction mechanism having a larger outer diameter than necessitated by the design requirements.
In an effort to overcome some of the deficiencies of the combination of a one-way torque transmitting mechanism and a parallel friction torque transmitting mechanism, it has been proposed to employ a valve mechanism within the friction torque transmitter that is direction sensitive. One such device is described in a Society of Automotive Engineering (SAE) publication 930911 and U.S. Pat. Nos. 5,031,746 and 5,106,348 issued to Erkki Koivunen. While these devices are effective in eliminating the roller or sprag, they require additional valving and cam surfaces to be incorporated into the friction torque transmitting mechanism.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide an improved torque transmitting mechanism providing both direction sensitive torque transmission and selectively controlled bi-directional torque transmission.
In one aspect of the present invention, a multi-plate friction mechanism has a threaded hub drivingly connected with one set of friction plates and threadably engaged with a threaded portion of a transmission slidably housing a fluid operated piston. In another aspect of the present invention, a stop member is secured with the threaded portion to limit the travel of the threaded hub in one direction along the threaded portion.
In yet another aspect of the present invention, a bearing supporting relative rotation is positioned between the piston housing and an apply plate that is drivingly connected with the threaded hub. In still another aspect of the present invention, the threaded hub is secured with a stationary portion of the transmission and the bearing is secured with the piston.
In a further aspect of the present invention, a single fluid operated friction torque transmitting mechanism is controlled to operate as a coast braking torque transmitter, a direction sensitive torque transmitter and a conventional fluid operated torque transmitter. In a yet further aspect of the present invention, the torque transmitter can be either a stationary reaction member, such as a brake, or a rotating member, such as a clutch.
REFERENCES:
patent: 1841284 (1932-01-01), Gillett
patent: 2799375 (1957-07-01), Forster
patent: 3273681 (1966-09-01), Seifert
patent: 3730314 (1973-05-01), Herr et al.
patent: 4253557 (1981-03-01), Bunger
patent: 5106348 (1992-04-01), Koivunen
patent: 5281190 (1994-01-01), Koivunen
patent: 5462147 (1995-10-01), Sherman
patent: 6039160 (2000-03-01), Joppeck
“The Weller Clutch” as described in Gott, Philip G., “Changing Gears; The Development of the Automotive Transmission” SAE Historical Series, 1991 originally published in Roos, Delmar G., James, William S., “Free Wheeling” SAE Transactions, vol. 26, 1931, p. 393.
Hurst, John W., “Chrysler's New 300 Sterndrive”, SAE 770713.
Koivunen, Erkki et al. “The Multi-Mode Clutch—A New Technology for Free-Wheeler Shifting Automatic Transmissions” SAE 930911.
Bonck Rodney H.
General Motors Corporation
Hargitt Laura C.
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