Patent ID: 12228191

DETAILED DESCRIPTION

As used in the description that follows, directional terms such as “upper” and “lower” are used with reference to the orientation of the elements as presented in the figures. Accordingly, “upper” indicates a direction toward the top of the figure and “lower” indicates a direction toward the bottom of the figure. The terms “left” and “right” are similarly interpreted. The terms “inward” or “inner” and “outward” or “outer” indicate a direction that is generally toward or away from a central axis of the referred to part, whether or not such an axis is designated in the figures. An axial surface is therefore one that faces in the axial direction. In other words, an axial surface faces in a direction along the central axis. A radial surface therefore faces radially, generally away from or toward the central axis. It will be understood, however, that in actual implementation, the directional references used herein may not necessarily correspond with the installation and orientation of the corresponding components or device.

Referring now to the drawings, a torque converter architecture embodying the principles of the present invention is generally illustrated inFIG.1and designated at10. The torque converter architecture10is positioned between the prime mover12and the input of a subsequent/downstream drivetrain element, gear reduction mechanism or other device14, one of which is seen inFIG.2. The prime mover10may be an internal combustion engine (ICE) and electric motor (EM) or combination of the two (ICE/EM).

As its general components, the torque converter architecture10includes a selectable switching device16, a torque converter18and an output20, such as an output shaft. During operation, torque from the prime mover12is transferred to the selectable switching device16. Depending on the state of the selectable switching device16, the torque from the prime mover12may be directed to the torque converter18and then the output20(a first operational state) or directly to the output20(as second operational state). When a direct drive condition is desired between the output of the prime mover12and the input of the downstream device14, the selectable switching device16passes torque directly to the output20. In this second operational state, the torque converter18is completely bypassed and no rotational input is provided to the torque converter18.

The torque converter18provides a hydrodynamic circuit that is configured to multiply an input torque and transmit the increased torque as an output torque to the driven downstream device14. The torque converter18includes a front cover22and a rear cover24, which together cooperate to define a shell26. The shell26further defines an internal chamber28where the hydrodynamic circuit is provided.

An input shaft29transmits torque to the torque converter18, which is received by the shell26, typically at the front cover22, and transferred to an impeller30, which is typically attached internally to the rear cover24. The impeller30directs the hydrodynamic fluid radially outward and then axially forward, toward a turbine32. The force imparted on the turbine32by the fluid rotationally drives the turbine32. From the turbine32, the fluid is directed radially inward and subsequently axially back toward the impeller30. A stator34, positioned between the turbine32and the impeller30and supported by a one-way clutch35, redirects the fluid so as to efficiently transfer the fluid to the impeller30, thereby multiplying the torque being transferred.

The turbine32is connected to a turbine output hub36, and the turbine output hub36transfers the output torque by way of an intermediate output member37and a one-way clutch38to the output member20, which transmits the torque to the downstream device14. As an alternate to the one-way clutch38, a clutch/selectable device may be used. A damper assembly, not shown, may also be provided in the torque converter18for NVH isolation before transfer of the output torque to the output member20.

As previously mentioned, typically, a lock-up clutch assembly comprised of a piston/clutch assembly is provided within a torque converter to allow the torque converter to lock the input from its front cover with the turbine output hub. Locked-up in this manner, torque being transmitted to the downstream device bypasses the hydrodynamic circuit of the impeller and turbine. However, the front and rear covers, impeller, turbine, stator, damper and other components of the torque converter are still rotating, along with the associated inertia and efficiency losses.

With the present torque converter architecture18, a lock-up clutch is omitted from the torque converter18in favor of the upstream selectable switching device16. Thus, in addition to avoiding losses due to rotation of the torque converter during a lock-up condition, the torque converter's overall mass is reduced and a high pressure hydraulic circuit, for operating the lock-up clutch, is removed.

The architecture10embodying the principles of the present invention may be implemented in other constructions utilizing torque transfer devices other than torque converters. For example, another device, such as a fluid coupling device, hydrostatic coupling device or other device that transmits torque, could be used in place of the torque converter18.

For the selectable switching device16, it will be appreciated that various types of selectable clutches/devices may be employed. Illustratively, such devices include, without limitation, hydraulic clutches, synchronizers, and selectable electric clutches. As described, such devices must be of a type that when implemented allow the torque transferred from the selectable switching device16to be alternately directed to the input shaft29of the torque converter18or directly to the output member20.

While schematically illustrated inFIG.1, seen inFIG.2is modified physical implementation of the torque converter architecture10. As seen therein, the prime mover12is represented by a torque generator, namely an electric motor (EM)40having a fixed stator41and rotatable rotor42. (While shown as an EM, the prime mover12could alternatively be shown as an internal combustion engine (ICE) or a combination of both.) When torque is provided via the rotor42of the EM40, torque is transferred to the selectable switching device16. Depending on the state of the selectable switching device16, torque is transferred to one of two output drive members44,46and, respectively, to either the input shaft29of the torque converter18or to output member20, but not simultaneously to both. As seen inFIG.2, the output member20is provided as an output shaft and is concentrically located within the input shaft29. The output member20and input shaft29are supported for independent rotation relative to one another by bearings or other means.

When directing torque to the torque converter18, torque is transferred from the selectable switching device16to the input shaft29, which is fixedly coupled to the front cover22of the torque converter's shell26and rotationally drives the rear cover24. As discussed above, the fluid coupling between the impeller30(which is carried by the rear cover24) and turbine32drives the turbine32and the stator34efficiently reverts the hydraulic fluid back to the impeller, whereby torque is multiplied and transferred back to the turbine32. The turbine32again includes a turbine output hub36that is coupled via the one-way clutch38to the output member20and drives the output shaft20in the first state of the selectable switching device16.

As seen inFIG.2, the output member20is also the input shaft46of the downstream device14, which is shown as a gearbox or transmission48. The gearbox48includes a shift fork50axially riding on a shift rail52to couple the input shaft48to either forward drive gear set54or a rearward drive gear set56, via a synchronizer58, thereby providing both forward and rearward operation of the gearbox48. Provided in this manner, when torque is directed through the through the torque converter18, it will be appreciated that torque multiplication can be employed during both forward and rearward operation and outputted via output shaft60to a further driven device or component (not shown). It will further be appreciated that various types of engaging/switching mechanisms between the forward and reverse could be employed in place of that described above.

When directing torque and bypassing the torque converter18, torque is transferred from the selectable switching device16directly to the output member20via output drive46. The output member20thereafter directly operates as the input shaft48of the downstream device14/gearbox48as described above, absent of torque multiplication.

In an alternative construction of the architecture, a second torque transfer device64may be implemented between the selectable switching device16and the output member20when the selectable switching device16is in the second state. The second torque transfer device64is preferably of a different variety of torque transfer device than the torque converter18and, for example, may be a slip clutch or a peak torque limiter or other device.

With the prime mover12(shown as EM40inFIG.2) directly driving the output member20, the torque converter18is not driven, maximizing efficiency, and may actually cease to rotate. To enable reconnecting of the non-driven torque converter18with the prime mover12over the operating speed range of the system, optionally, a synchronizing device62may be employed. The synchronizing device62is seen in the schematic drawing ofFIG.1.

The synchronizing device62brings the input shaft29, shell26and impeller30of torque converter18up to a speed, which is within a specific speed differential range, relative to the rotation of output member of the prime mover12, thereby allowing the selectable switching device16to be readily re-engaged for transmitting torque through the torque converter18. Alternatively, the synchronizing device62may bring the input shaft29up to a speed, within the specific speed differential range, relative to the rotation of the output member20.

The synchronizing device62may be provided in the form of a hydraulic clutch, an electric clutch, an e-motor, or other device (manual or automatic). A clutch device is schematically shown inFIG.1as the synchronizing device62), but is not limited thereto. In another alternate construction, the synchronizing device62may be combined and/or integrated into a single device16′ with the selectable switching device16.

The above description is meant to be illustrative of at least one preferred implementation incorporating the principles of the invention. One skilled in the art will really appreciate that the invention is susceptible to modification, variation and change without departing from the true spirit and fair scope of the invention, as defined in the claims that follow. The terminology used herein is therefore intended to be understood in the nature of words of description and not words of limitation.