Machine element or mechanism – Gearing – Interchangeably locked
Reexamination Certificate
2001-06-22
2002-11-05
Estremsky, Sherry (Department: 3681)
Machine element or mechanism
Gearing
Interchangeably locked
C074S473120, C074S473180
Reexamination Certificate
active
06474186
ABSTRACT:
FIELD OF THE INVENTION
The present invention pertains to a shifting device for an automatic transmission controlled by an electronic control device for vehicles, especially motor vehicles, with a first shifting device, in which different gears to be shifted automatically can be preselected by manual selection, and with a second shifting device, which can be actuated by a selector device and in which the selector device is held in the neutral middle position, from which it can be moved by manual actuation in a first direction for inducing upshiftings and in a second direction for inducing downshiftings, wherein the shifting movements of the selector device are detected by device of sensors and are sent as signals to the control device.
BACKGROUND OF THE INVENTION
Shifting devices in which a driver selects an automatic travel mode by device of a selector lever have been known from practice, e.g., in passenger car automatic transmissions with electronic control. A shift gate with a plurality of sensors is usually provided for this purpose for the selector lever, where a shift position each of a dynamic shifting program is associated with the sensors. Thus, e.g., a shift position P for park, R for reverse, N for neutral (idle) and D for forward travel (drive), in which automatic shifting between the lowest gear and the highest available gear is performed as a function of the speed with which the gas pedal, the engine speed, the vehicle acceleration and other important variables available in an electronic control device are adjusted, can be mechanically selected with the selector lever. The electronic control device of the automatic operation contains for this purpose modules which automatically change the shifting characteristics of the transmission depending on the driving style and the driving situation.
In addition, such prior-art shifting devices frequently have shift positions for a maximum gear to which upshifting is possible. For example, a fifth gear can be blocked with a shift position “
4
” if an excessively frequent gear change between the fourth and fifth gears takes place under certain driving conditions, whereas, e.g., upshifting into a higher gear, e.g., on a longer uphill section and on downhill sections in mountains, is prevented from taking place with a shift position “
2
.” Besides, a shift position for the first gear may, of course, be provided as well. Better utilization of the engine output with the use of the engine brake effect can be achieved by the provision of such shift positions for different shifting ranges and a needless upshifting and downshifting is avoided.
To make possible a single manual shifting between the individual gears and to offer the driver the possibility of manual operation, e.g., to achieve a more sporty driving style, such prior-art shifting devices often have an additional shifting device for the so-called “tap shifting,” in which shifting into the next lower or next higher gear can be performed by tapping a corresponding sensor by device of the selector lever or a separate switch or button.
Such a shifting device has been known from DE 38 07 881 C2, where the “manual program” of tap shifting is embodied by device of a second shift gate which is parallel to the shift gate of the dynamic shifting program. To carry out the manual program, the selector lever is switched over via a transverse gate into a second shift gate, in which it is held in the neutral middle position by springs and induces upshifting and downshifting during manual pivoting by the shifting movements of the selector lever being detected by sensors, whose signals are sent to the control device of the automatic transmission.
In all described solutions with a manual tap shifting, upshifting into a higher gear is performed manually by tapping a plus sensor and downshifting into the next lower gear is performed manually by tapping a minus sensor, in addition to a dynamic shifting program.
In certain driving situations, in which, e.g., downshifting by several gears or intense upshifting is desirable for extremely great acceleration, this has the drawback that the plus sensor or the minus sensor must be tapped repeatedly in succession. Not only does this compromise the operating comfort, but it may also lead to delays in the manual program, which may jeopardize safety, and to inappropriate behavior on the part of the driver in critical driving situations, e.g., during passing.
SUMMARY AND OBJECTS OF THE INVENTION
The object of the present invention is therefore to provide a shifting device for an automatic transmission controlled by an electronic control device for vehicles, especially for motor vehicles, in which downshifting or upshifting by several gears is simplified in terms of operation in a manual program.
A shifting device for an automatic transmission controlled by an electronic control device for vehicles, especially motor vehicles, has a first shifting device in which different gears to be shifted automatically can be preselected by manual selection. The device has a second shifting device, which can be actuated by a selector and in which the selector is held in the neutral middle position, from which it can be moved by manual actuation in a first direction for inducing upshiftings and in a second direction for inducing downshiftings. The shifting movements of the selector are detected by sensors and are sent as signals to the control device. The second shifting device has a shift position for the selector for single downshifting into the next lower gear and another shift position (−−) for maximum downshifting into the gear with the lowest possible ratio and/or a shift position (+) for the selector for single upshifting into the next higher gear and another shift position (++) for maximum upshifting into the gear with the highest possible ratio.
The operating comfort for the desired downshiftings or upshiftings by several gears in the manual program is optimized for the driver with the shifting device according to the present invention.
Contrary to conventional tap shifting, it is no longer necessary to perform a separate tapping movement of the selector device for each gear to which downshifting or upshifting is to be performed, but a single tapping movement is sufficient in order to perform a maximum downshifting or upshifting.
In an especially advantageous embodiment of the present invention, provisions may be made to provide an increased movement resistance for the selector device at the transition from the shift position for the single downshifting into the shift position for the maximum downshifting and at the transition from the shift position for single upshifting into the shift position for maximum upshifting. The driver will thus clearly notice that he selects the shift position for maximum downshifting or maximum upshifting, so that an accidental tapping of this shift position and consequently an undesired shifting or even a shifting compromising the stability of the vehicle is clearly avoided. Provisions may, of course, be made that only one shift position is present for single upshifting while the shift positions for single downshifting and for maximum downshifting are available for the downshifting, because a maximum downshifting is desirable especially for sporty drivers more frequently than a maximum upshifting.
The shifting device according to the present invention is especially suitable for motor vehicles with an electronically controlled vehicle automatic transmission, which may be a sequential automatic transmission or a CVT automatic transmission. However, applications in other types of vehicles, e.g., motorcycles or watercraft with electronically controlled vehicle automatic transmissions are also conceivable, because the drivers of such vehicles also frequently wish to have shiftings, especially downshiftings, with maximum speed by several gears.
The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For
Estremsky Sherry
McGlew and Tutle, P.C.
ZF Lemförder Metallwaren AG
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