Shift error safeguard for a transmission in a motor-vehicle

A shift safety device (26) for a motor vehicle manual transmission comprising a gear shift shaft (28) that is rotatable for selecting shift gates and being axially movable for shifting gear steps, the shift safety device comprising:

• a blocking element (38) has a contact contour (66), and the blocking element, which during a selector motion towards an adjacent shift gate, is moved by the gear shift shaft (28) using the contact contour (66) thereof against a force of a return spring out of a starting position into a blocked position, the blocking element in the blocked position blocks further selector motion of the gear shift shaft (28), and, during a subsequent shifting motion of the gear shift shaft (28), the blocking element is released and returned by the return spring into the starting position thereof for permitting further selector motion;
• a radially projecting driver arm (36) is disposed on the gear shift shaft (28), a free end (68) of the radially projecting driver arm (36) has a contact contour (72) that interacts with the contact contour (66) of the blocking element (38), the blocking element (38) is movably disposed in a surrounding structure (44) of the gear shift shaft (28) that is fixed to a housing and the blocking element is moved in a direction substantially tangential to an arcuate track that is traversed, during the selector motion, by the free end (68) of the radially projecting driver arm (36) to move the blocking element between the starting position thereof and the blocking position thereof, the blocking element (38) being substantially movably supported in a direction of a linear track traversed by the free end (68) of the radially projecting driver arm (36) during the shifting motion, parallel to a longitudinal axis (32) as defined by the gear shift shaft (28);
• the blocking element (38) is pretensioned, toward the starting position thereof, by the return spring and is pretensioned along the linear track, toward a center position, by centering spring means (62, 64);
• the blocking element (38) is accommodated within a supporting housing (40), the blocking element is movable between the starting position thereof and the blocking position thereof, and the supporting housing (40) is displaceably mounted in the surrounding structure (44);
• and
• the supporting housing (40) is cylindrical with a longitudinal axis which is parallel to the gear shift shaft (28), the supporting housing (40) has a radial recess (48) for movably accommodating the blocking element (38) which is shaped as a plate, the return spring is disposed between the blocking element (38) and a bottom of the radial recess (48), the supporting housing (40) has a first axial side face which supports a first guiding rod (54) which is movably disposed relative to a first bearing mounting (58), and the supporting housing (40) has a second axial side face which supports a second guiding rod (56) which is movably disposed relative to a second bearing mounting (60), and the centering spring means comprises first and second compression springs, which bias the supporting housing (40) toward the center position, the first and the second compression springs are disposed between a respective one of the first and the second axial side faces of the supporting housing (40) and a respective one of the first and the second bearing mountings (58, 60).

A shift safety device (26) for a motor vehicle manual transmission comprising a gear shift shaft (28) that is rotatable during a selector motion to select shift gates and is axially movable during a shifting motion to shift gear steps, the shift safety device comprising:

• a blocking element (38) has a contact contour (66), the blocking element which, during the selector motion of the gear shift shaft towards an adjacent shift gate, is biased by the gear shift shaft (28) using the contact contour (66) thereof against a force of a return spring (50, 52) out of a starting position into a blocked position, the blocking element in the blocked position blocks a further selector motion of the gear shift shaft (28) and, during a subsequent shifting motion of the gear shift shaft (28), the blocking element is released and then returned by the return spring (50, 52) into the starting position thereof for permitting the further selector motion, a radially projecting driver arm (36) is fixed to the gear shift shaft (28), a free end (68) of the radially projecting driver arm (36) has a contact contour (72) that interacts with the contact contour of the blocking element (38),
• the blocking element (38) being movably arranged within a supporting housing that is movably disposed in a surrounding structure (44) of the gear shift shaft (28) such that the blocking element is movable tangentially to an arcuate track that is traversed during the selector motion by the free end (68) of the radially projecting driver arm (36) between the starting position thereof and the blocking position thereof, the blocking element in the starting position thereof extends from the supporting housing,
• the blocking element (38) being substantially movably supported in a direction of a linear track traversed by the free end (68) of the radially projecting driver arm (36) during the shifting motion of the gear shift shaft, parallel to a longitudinal axis (32) of the gear shift shaft (28), and the blocking element (38) being pretensioned, toward the starting position thereof, by the return spring and along the linear track, toward a center position, by centering springs (62, 64).