Device and method for sensing the position of a shift fork of a transmission

A device (30) having a Hall sensor apparatus (10) for sensing a position of a shift fork (7) in a transmission (1), comprising:

• the shift fork (7) operatively connected to a piston rod (6) of a shifting piston (2) that moves axially in a shifting cylinder (3);
• a sliding sleeve (8) engaged with the shift fork, which is arranged in an axially slidable fashion on a transmission shaft (9), wherein a sliding of the sliding sleeve (8) engages or disengages a transmission stage of the transmission (1);
• a magnet (13, 28) operating as a signal generator and arranged on an adjustable actuating element selected from the group consisting of:
• the shifting piston (2), the piston rod (6), and the shift fork (7);
• a 3D Hall sensor (11, 29) operating as a signal receiver arranged in a positionally fixed fashion relative to the magnet (13, 28), wherein the 3D Hall sensor operates as a signal receiver operable to spatially sense a magnetic field generated by the magnet (13, 28);
• and
• an electronic control unit (31) connected to the 3D Hall sensor,
• wherein the electronic control unit (31) is operable to determine a current position of the shift fork (7) from a position of the magnet (13, 28) relative to a position of the 3D Hall sensor (11, 29), and converts the position of the shift fork to a signal, under consideration of a linear movement, a rotational movement, or a pivoting movement of the adjustable actuating element (2, 6, 7),
• wherein the 3D Hall sensor (11, 29) has a sensor head (14) with an electrical interface (24) and a sensor finger (15) connected to the sensor head (14), wherein the sensor finger (15) projects through a housing wall (17) of the transmission into the oil space (19) of the transmission (1) in the direction of an assigned magnet (13, 28), and the sensor head (14) is attached to an outer side of the housing wall (17) of the transmission in an oil-tight fashion with respect to the oil space (19).

A method for determining a position of a shift fork (7) in a transmission (1) with a Hall sensor apparatus (10), comprising the following steps:

• attaching a magnet to a shifting piston, a piston rod, or a shift fork, wherein the shift fork (7) is operatively connected to the piston rod (6) of the shifting piston (2), the shifting piston is guided in an axially movable fashion in a shifting cylinder (3), and the shift fork (7) engages a sliding sleeve (8) which is axially slidable on a transmission shaft (9) to engage or disengage a transmission stage of the transmission (1), and
• spatially sensing a magnetic field of the magnet (13, 28) via a positionally fixed single 3D Hall sensor (11, 29),
• wherein at least two of the following three movements move the magnet therewith and change the position of the magnet with respect to the positionally fixed single 3D Hall sensor (11, 29), and a current position of the shift fork (7) is determined via a sensor signal of the single 3D Hall sensor (11, 29) based on the at least two of the following three movements:
• a linear actuating movement of the shifting piston or of the piston rod, a rotational actuating movement of the shifting piston (2) or of the piston rod (6), and a pivoting movement of the shift fork (7).