METHOD FOR OPERATING AN AUTOMATIC TRANSMISSION APPARATUS AND CORRESPONDING AUTOMATIC TRANSMISSION APPARATUS

Abstract

A method for operating an automatic transmission apparatus having a parking lock device. The parking lock device has a hydraulic apparatus with a hydraulic cylinder and a hydraulic piston arranged therein, which can be placed in at least two positions by a lock apparatus and an emergency unlock apparatus. The hydraulic piston is operatively connected to a shifting shaft of the parking lock device, and a pressure can be adjusted in the hydraulic cylinder by a hydraulic valve. The shifting shaft can be shifted within an operating position range by the hydraulic apparatus. In doing so, upon activation of the emergency unlock apparatus, the shifting shaft is shifted into a position that is outside of the operating position range, and an operating state of the emergency unlock apparatus is checked.

Claims

1-8. (canceled)

9. A method for operating an automatic transmission apparatus having a park locking device, wherein the park locking device has a hydraulic apparatus with a hydraulic cylinder and a hydraulic piston arranged therein, which can be placed in at least two positions by a lock apparatus, as well as an emergency unlock apparatus, wherein the hydraulic piston is operatively connected to a shifting shaft of the park locking device, and a pressure in the hydraulic cylinder can be adjusted by a hydraulic valve, and wherein the shifting shaft can be shifted within an operating position range by the hydraulic apparatus, comprising: upon activation of the emergency unlock apparatus, the shifting shaft is shifted into a position that is outside of the operating position range, and an operating state of the emergency unlock apparatus is checked, wherein an activated emergency unlock apparatus is detected when a position of the shifting shaft, which is outside of the operating position range, is determined over a specific timeframe by a position sensor, and when a distance traveled by the shifting shaft, detected by the position sensor, exceeds a limit value.

10. The method according to claim 9, wherein the checking of the operating state is initiated when at least one of the following occurs: a park position is set on the automatic transmission apparatus; a position of the shifting shaft, which lies within the operating position range, is determined by the position sensor; the lock apparatus is activated for setting the hydraulic piston; and the target current of the hydraulic valve corresponds to the actual current.

11. The method according to claim 9, wherein the checking of the operating state is initiated when a drive setting that is different from the park setting is set on the automatic transmission apparatus.

12. The method according to claim 9, wherein the checking of the operating state is initiated as soon as an internal combustion engine is started and a voltage supply is established for igniting the internal combustion engine.

13. The method according to claim 9, wherein an operating state of the hydraulic apparatus, which has the hydraulic cylinder and the hydraulic valve, is monitored, and an operating state of the lock apparatus is monitored.

14. The method according to claim 13, wherein the checking of the operating state of the emergency unlock apparatus is suspended when the operating state of the hydraulic apparatus and the operating state of the lock apparatus indicate a defect.

15. The method according to claim 9, wherein an electromagnetic lock apparatus is used as the lock apparatus.

16. An automatic transmission apparatus, having a park locking device, wherein the park locking device has a hydraulic apparatus with a hydraulic cylinder and a hydraulic piston arranged therein, which can be placed in at least two positions by a lock apparatus, as well as an emergency unlock apparatus, wherein the hydraulic piston is operatively connected to a shifting shaft of the park locking device and a pressure in the hydraulic cylinder can be adjusted by a hydraulic valve, and wherein the shifting shaft can be shifted within an operating position range by the hydraulic apparatus, wherein, upon activation of the emergency unlock apparatus, the automatic transmission apparatus is designed to shift the shifting shaft into a position that is outside of the operating position range, and an operating state of the emergency unlock apparatus is checked, wherein an activated emergency unlock apparatus is detected when a position of the shifting shaft, which is outside of the operating position range, is determined over a specific timeframe by a position sensor, and when a distance traveled by the shifting shaft, detected by the position sensor, exceeds a limit value.

Description

[0030] The invention is explained in more detail in the following by means of exemplary embodiments shown in the drawing, without limiting the invention. In doing so, the only FIGURE shows a schematic representation of an automatic transmission apparatus having a park locking device.

[0031] The FIGURE shows a schematic representation of an automatic transmission apparatus 1, which is allocated to a motor vehicle, for example. In this context, the automatic transmission apparatus 1 may be provided in an operative connection between a drive apparatus of the motor vehicle and at least one driven axle of the motor vehicle. The automatic transmission apparatus 1 provides a park locking device 2, which has a hydraulic apparatus 3. The hydraulic apparatus has a hydraulic cylinder 4 and a hydraulic piston 5 arranged in said cylinder. The hydraulic piston 5 is operatively connected to a shifting shaft 6 of the park locking device 2, particularly directly attached to it.

[0032] With the assistance of the hydraulic apparatus 3, the shifting shaft 6 can be shifted in this regard, preferably within an operating position range. Furthermore, the park locking device 2 provides a lock apparatus 7, which has, for example, a plurality of electromagnetic assemblies 8. The shifting shaft 6 and/or the hydraulic piston 5 can be set at certain positions within the operating position range by means of the electromagnetic assemblies 8. The hydraulic cylinder 4 is hydraulically connected to a hydraulic valve 9. In particular, the hydraulic cylinder 4 is hydraulically connected to a hydraulic pressure source via the hydraulic valve 9. This means that the pressure in the hydraulic cylinder 4 can be adjusted by means of the hydraulic valve 9 and the hydraulic piston 5 can be shifted in this respect within the hydraulic cylinder 4.

[0033] In the schematic representation shown here, the hydraulic cylinder 4 is only connected to the one hydraulic valve 9. Obviously, there may be a provision that several hydraulic valves 9 or a hydraulic valve assembly is hydraulically connected to the hydraulic piston 4, wherein the valves or the assembly is (are) preferably provided on opposite sides of the hydraulic piston 5, so that the hydraulic piston 5 can optionally be loaded with hydraulic pressure by either side and can be shifted in this respect.

[0034] The park locking device is activated by means of the hydraulic apparatus 3 via the shifting shaft 6. In a first position, the park locking device 2 in this case is provided to release the automatic transmission apparatus 1, while, in a second position, the park locking device 2 locks the automatic transmission apparatus 1, so that an operative connection in this respect is interrupted between an input shaft 10 and an output shaft 11. In particular, the output shaft 11 can be completely set by means of the park locking device 2 so that the motor vehicle is secured against rolling away.

[0035] It is then a provision that the shifting shaft 6 can be shifted by means of an emergency unlock apparatus 12 (only implied here). The emergency unlock apparatus 12 is used to deactivate the park locking device 2, i.e. to effect the unlocking of the automatic transmission apparatus 1 when this is no longer possible based on the hydraulic apparatus 3 and/or the lock apparatus 7, for example, because a control unit activates the hydraulic apparatus 3 and the lock apparatus 7 for permanent activation of the park locking device 2. With the assistance of the emergency unlock apparatus 12, the shifting shaft 6 can be shifted in such a way that it is outside of the operating position range.

[0036] A provision is that an operating state of the emergency unlock apparatus 12 is checked. In doing so, an activated emergency unlock apparatus 12 should be detected when, particularly over a specific timeframe, a position of the shifting shaft 6 is determined that is outside of the operating position range by means of a position sensor, which is not shown here. A provision may also be to record a distance by which the shifting shaft is shifted by means of the position sensor, in particular over the timeframe. If the recorded distance exceeds a certain limit value, particularly if the position of the shifting shaft 6 recorded by means of the position sensor deviates at least by the limit value from that position in which the park locking device is activated, the activated emergency unlock apparatus 12 is detected, particularly when additionally the position is outside of the operating position range.

[0037] In addition, there can be a check to determine whether the lock apparatus 7 has set the hydraulic piston 5 in one of the positions over the specific timeframe. Additionally or alternatively, there can be a check to determine whether a deviation between a target current of the hydraulic valve 9 and an actual current is smaller than a certain limit value over the specific timeframe. For example, several, and particularly all, of the aforementioned conditions must be fulfilled so that the activated emergency unlock apparatus 12 is detected.

[0038] In this manner, a reliable detection is possible as to whether the automatic transmission apparatus 1 has been released by means of the emergency unlock apparatus 12.