Machine element or mechanism – Gearing – Interchangeably locked
Reexamination Certificate
2002-03-07
2003-09-09
Estremsky, Sherry (Department: 3681)
Machine element or mechanism
Gearing
Interchangeably locked
C074S473110, C074S473130, C074S473300
Reexamination Certificate
active
06615682
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a device for gutter selection in a transmission, in particular, in AMT systems (automatic manual transmission) as well as a method for the gutter selection in a transmission.
2. Description of the Related Art
In so-called automatic manual transmissions (AMT) the gears of the transmission are shifted by means of an electro-hydraulic actuator. In this connection, the actuator for a transmission with an “H” shifting pattern is configured of several pistons and corresponding mechanisms in order to carry out the gear shifting movement and/or gutter movement.
Such an actuator is known, for example, from DE 199 31 973 A1. In this connection, a complexly configured unit comprised of actuating devices, sensors, and valve devices is proposed in order to move a selector finger in a gutter of the transmission.
In
FIG. 5
, a different gutter selection actuator is illustrated. As shown in
FIG. 5
, the actuator comprises six piston elements
31
,
32
,
33
,
34
,
35
, and
36
in order to position the selector shaft
37
in one of the transmission gutters N
1
, N
2
, N
3
or N
4
. The position of the piston units
31
through
36
is determined by control of two switching valves SV
1
and SV
2
. Such an actuator requires a complex mechanical configuration and has a plurality of components. This results in an increased manufacturing expenditure and a highly branched hydraulic line system. Moreover, a control must be provided in order to control the two switching valves SV
1
and SV
2
.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a device as well as a method for gutter selection which enables a safe and reliable gutter selection while providing a simple configuration and a simple, inexpensive manufacture.
This object is solved by an actuator for gutter selection comprising a selector shaft with a selector finger and a gutter selection device which is movable back and forth along an axis in order to assume a first position and a second position, wherein the selector finger of the selector shaft can be moved into engagement and out of engagement with the gutter selection device and wherein the position of the gutter selection device can be determined by means of precisely one valve device. The object is further solved by a method for gutter selection comprising the steps of positioning the gutter selection device, movable back and forth along an axis, in a first position depending on the desired next gutter selection; connecting a selector shaft with the gutter selection device; moving the gutter selection device with the selector shaft into a second position so that the selector shaft is positioned in a neighboring gutter; and disengaging the selector shaft from the gutter selection device in order to shift a gear, wherein the movement of the gutter selection device from the first position into the second position is carried out by means of precisely one valve device. Advantageous embodiments are the subject matter of the dependent claims, respectively.
According to the invention, an actuator for gutter selection of a gear positioning device for an automatic manual transmission is thus proposed which comprises a selector shaft with a selector finger and a gutter selection device. The gutter selection device is movable back and forth along an axis and, in this connection, assumes a first position and a second position. In this way, the gutter selection device can assume only precisely two positions. In this connection, the selector finger of the selector shaft can be engaged with and disengaged from the gutter selection device. The position of the gutter selection device is determined in this connection by precisely one valve device.
Accordingly, the gutter selection actuator according to the invention is of a very simple configuration because the selection of the gutter can be realized with a single valve device. In this connection, only one gutter selection device is required which is controlled by the only valve and which must perform only an axial reciprocating movement in order to perform the gutter selection. Accordingly, the actuator according to the invention for gutter selection only has a minimal number of components so that a minimal manufacturing expenditure and a minimal assembly expenditure result. Accordingly, the actuator according to the invention for gutter selection can be manufactured significantly less expensively in comparison to previously employed gutter selection actuators. Due to the minimal number of components the reliability of the system can also be improved.
Moreover, since only one valve device is employed, savings in regard to electronic compounds and in regard to a wiring harness result also, since only one valve device must be controlled. Moreover, the system according to the invention does not require a sensor because the position of the gutter selection device is determined simply by the position of the valve device. Accordingly, no redundancy sensor is necessarily required which could maintain an emergency operation when the sensor fails. Since the gutter selection device and the selector finger are completely out of engagement after gutter selection, it is also ensured that, when the gear is engaged, no forces are exerted by the gutter actuator onto the transmission. This increases the service life of the transmission.
Preferably, the gutter selection device is embodied as a piston which is loaded with a pressure medium. In this connection, the piston can be guided simply in a housing and can have a simple configuration. The control of the piston is realized in this connection via the valve device which supplies the pressure medium to the piston. The pressure medium is preferably a hydraulic liquid.
It is especially preferred to embody the piston as a double-action piston. In this connection, the valve device controls the piston on a certain piston end as a function of the position of the piston. Preferably, the piston has two piston surfaces with differently sized surface areas. This enables that the piston can be loaded on both surfaces with a control pressure of the same magnitude and that the piston is always in a defined position.
Advantageously, the gutter selection device is provided with cutouts for engagement by the selector finger. In this way, a positive-locking connection between the gutter selection device and the selector finger can be provided.
Preferably, the cutouts are arranged such on the gutter selection device that the selector finger can engage the gutter selection device by means of a pivot movement. This enables a simple and safe course of movement for the selector finger for engaging and releasing the gutter selection device.
Preferably, the selector finger can pivot in two directions in and out of the gutter selection device. In this way, the individual gears can be selected by a direct pivot movement out of the gutter selection device. This enables an especially compact configuration.
Preferably, the number of cutouts provided in the gutter selection device is smaller by one compared to the number of the gutters of the transmission. This means that when the transmission has, for example, four gutters, the gutter selection device has three cutouts. In this way, the constructive size of the gutter selection device can be kept small.
Preferably, the stroke of the piston (gutter selection device) matches the spacing of two neighboring gutters of the transmission. This ensures that the selector finger or the selector shaft are moved precisely by one next gutter.
In order to provide an additional safety device in regard to the position of the gutter selection device, a sensor is preferably provided in order to determine the position of the gutter selection device. As has been explained before, the position of the gutter selection device can also be determined according to the invention simply by the position of the valve device.
In order to enable for a shifting process a skipping of gutters, the selecto
Meyer Roland
Schmidt Thomas
Weigert Wolfgang
Wild Andreas
Huckett Gudrun E.
Hydraulik-Ring GmbH
Lewis Tisha D.
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