Locking device for reverse gear of a motor vehicle transmission, especially for an automobile

Claim 2

A locking device for a reverse speed of a motor vehicle transmission, especially an automobile, the transmission including a transmission housing, a driven shaft, a friction ring adapted to be brought into frictional engagement with a reverse gear wheel when shifting into a reverse speed, the friction ring cooperating with a dog which is spring-loaded in an axial direction, the dog selectively displacing locking elements into a locking position for preventing engagement of the reverse gear wheel during predetermined operating conditions of the transmission, characterized in that the friction ring is non-rotatably and slidably mounted on the driven shaft between the gear wheel and the dog, the gear wheel is freely rotatably mounted on the driven shaft and is adapted to be selectively coupled thereto, and in that the dog is arranged on portions of the transmission housing so as to be coaxial with respect to the driven shaft.

Claim 3

A locking device according to claim 1, characterized in that the transmission housing includes a neck portion disposed coaxially to the driven shaft, a sleeve is non-rotatably connected with the neck portion of the transmission housing, the dog is slidably connected with the sleeve, and in that the sleeve is provided with at least one opening having guide surface means for guiding a movement of at least one of the locking elements.

Claim 4

A locking device according to claim 2, characterized in that a plurality of openings are provided in the sleeve spaced from each other in a circumferential direction, each of the openings includes guide surface means for guiding the movement of at least one locking element, and in that the locking elements are ball-shaped members interposed between the neck portion of the transmission housing and a portion of the dog.

Claim 5

A locking device according to claim 3, characterized in that the dog includes depressions for accommodating the ball-shaped members.

Claim 6

A locking device according to claim 4, characterized in that each of the guide surface means includes an axially directed guide surface, a further guide surface adjoining said axially directed guide surface and extending in a circumferential direction corresponding to a forward movement of the driven shaft, and a locking surface extending diagonally at least with respect to said further guide surface over at least a first linear portion thereof.

Claim 7

A locking device according to claim 5, characterized in that the gear wheel includes an inner cone portion having a frictional surface, the dog is arranged on an outer circumference of the neck portion of the transmission housing and includes a frictional surface along an outer circumference thereof, the friction ring includes a frictional surface along an inner and outer circumference thereof which respectively cooperate with the frictional surfaces on the dog and the gear wheel, a coupling ring is non-rotatably mounted on the driven shaft with the friction ring being disposed on the coupling ring, and in that, during a shifting operation of the transmission, the frictional surfaces of the gear wheel, friction ring and dog are brought into engagement with the dog being displaced in an axial direction along the neck portion of the transmission housing against biasing forces of compression springs when the locking device is ineffective, whereby the gear wheel meshes with a spline gearing of the coupling ring.

Claim 8

A locking device according to claim 5, characterized in that the dog is supported on an inner circumference of the neck portion of the transmission housing and cooperates with the friction ring by a frictional surface located on an inner circumference of the dog.

Claim 9

A locking device according to claim 7, characterized in that the gear wheel includes an axially extending elongated hub having splines disposed on an outer circumference thereof for engagement with splines provided on a sliding sleeve, the sliding sleeve including a frictional surface along an outer conical portion thereof, the friction ring is fashioned as a conical ring and is disposed on a coupling ring of the driven shaft, the friction ring includes a frictional surface engageable with the frictional surface of the sliding sleeve, and in that the coupling ring is arranged on the driven shaft adjacent the elongated hub and cooperates with the dog.

Claim 10

A locking device according to claim 7, characterized in that the gear wheel is provided with axial openings therein and a coupling means for a sliding sleeve of a shift gear disposed between the gear wheel and a gear of a forward speed, a first conical ring and a second conical ring are provided, said first and second conical rings being arranged on respective sides of the gear wheel, displaceably mounted pin means extend through the axial openings of the gear wheel for non-rotatably connecting the first conical ring with the second conical ring, the sliding sleeve is provided with a frictional surface cooperable with a portion of the first conical ring, and in that said second conical ring is brought into a frictional engagement with an inner conical portion of the friction ring during a shifting operation with the friction ring cooperating with an outer conical portion with the dog.