GEAR CHANGE DEVICE FOR A MOTOR VEHICLE

• US 20130019705A1
• Filed: 11/29/2011
• Published: 01/24/2013
• Est. Priority Date: 07/20/2011
• Status: Active Grant

• Current Assignee: C.R.F. Societa Consortile Per Azioni
• Original Assignee: C.R.F. Societa Consortile Per Azioni
• Inventors: Pregnolato, Gianluigi, Piazza, Andrea, Piacenza, Gianni
• Granted Patent: US 9,016,154 B2
• Time in Patent Office: Days
• US Class Current: 74/331
• CPC Class Codes: F16H 2003/0931 each countershaft having an output gear meshing with a single common gear on the output shaft
• CPC Class Codes: F16H 2063/025 Final output mechanisms for double clutch transmissions
• CPC Class Codes: F16H 2200/0056 the gear ratios comprising seven forward speeds
• CPC Class Codes: F16H 3/006 power being selectively transmitted by either one of the parallel flow paths
• CPC Class Codes: F16H 3/093 with two or more countershafts
• CPC Class Codes: F16H 61/688 with two inputs, e.g. selection of one of two torque-flow paths by clutches
• CPC Class Codes: F16H 63/18 the final actuating mechanism comprising cams
• CPC Class Codes: Y10T 74/19233 Plurality of counter shafts
• CPC Class Codes: Y10T 74/19288 Double clutch and interposed transmission

Abstract

A gear change device for including a first and a second primary shaft, selectively connectable to a driving shaft of a motor vehicle by a double clutch engagement device, and a first and a second secondary shaft. A plurality of gear selector devices rotatably couples each of freely rotatable gear wheels with the shaft on which it is mounted, and at least one rotatable actuator drum, for controlling the selector devices, having a plurality of cam tracks. The selector devices include respective fork-like actuator members and each has a cam follower element engaged in a respective cam track of the respective actuator drum. Each pair of cam tracks adjacent w each other provided on an actuator drum controls fork-like actuator members which are associated to different secondary shafts and which have the cam follower elements thereof engaged on the drum in positions angularly spaced with respect to each other.

Claims

1. Gear change device for a motor vehicle, comprising:

a first primary shaft and a second primary shaft coaxial with respect to each other, selectively connectable a driving shaft of the motor vehicle by a double clutch engagement device,

a first secondary shaft and a second secondary shaft, whose axes are parallel and spaced from the common axis of said primary shafts, and having respective output pinions intended to mesh with a gear wheel of a differential,

a plurality of pairs of gear wheels, corresponding to a plurality of forward gear ratios and to at least one reverse gear ratio, wherein the gear wheels of each pair are one rigidly connected in rotation with one of the primary shafts or with one of the secondary shafts while the other is freely rotatable on one of the secondary shafts or on one of the primary shafts, respectively

a plurality of gear selector devices for rotatably coupling each of said freely rotatable gear wheels with the shaft on which it is mounted,

wherein the reverse gear ratio is defined by;

a first reverse gear wheel mounted freely rotatable on the first secondary shaft and connectable in rotation with the first secondary shaft by one of said selector devices, with the aim of selecting the reverse gear,

at least one rotatable actuator drum, for controlling said selector devices, having a plurality of cam tracks,

wherein said selector devices include respective fork-like actuator members slidably mounted in a direction parallel to the axes of said primary and secondary shafts and each having a cam follower element engaged in a respective cam track of said at least one actuator drum,

wherein each pair of cam tracks adjacent to each other provided on said at least one actuator drum controls fork-like actuator members which are associated to different secondary shafts and which have the cam follower elements thereof engaged on said at least one drum in positions angularly spaced with respect to each other.

2. Gear change device according to claim 1, wherein at least two cam tracks adjacent to each other of said at least one actuator drum occupy drum sections axially superimposed with respect to each other, so that the overall space axially occupied by the two tracks is smaller than the sum of the single axial overall dimensions of said tracks.

3. Gear change device according to claim 1, wherein each of said fork-like actuator members has an extended body with a fork-shaped end and the opposite end carrying the respective cam follower element, said body of each fork-like actuator member being slidably mounted on a pair of guide rods spaced from each other and parallel to the axes of said primary and secondary shafts.

4. Gear change device according to claim 3, wherein the axes of the two secondary shafts and the common axis of said primary shafts have a triangular arrangement, with said secondary shafts arranged on one side, with respect to said common axis, which is diametrically opposite to the side on which said at least one drum is arranged, said actuator members having the extended bodies thereof shaped with a curvature surrounding said primary shafts.

5. Gear change device according to claim 3, further comprising two pairs of cam tracks and two pairs of fork-like actuator members respectively associated to the two secondary shafts, the two actuator members associated to the same secondary shaft being slidably mounted on the same pair of guide rods

6. Gear change device according to claim 5, further comprising a single drum carrying two pairs of cam tracks axially distributed along the drum.

7. Gear change device according to claim 5, further comprising two drums coaxially mounted one on the extension of the other and carrying two respective pairs of cam tracks, axially distributed along the two drums.

8. Gear change device according to claim 1, further comprising two pairs of cam tracks and that the cam tracks of each pair, which are associated to different secondary shafts, controls either all, even or all odd forward gears.

9. Gear change device according to claim 4, further comprises two pairs of cam tracks and two pairs of fork-like actuator members respectively associated to the two secondary shafts, the two actuator members associated to the same secondary shaft being slidably mounted on the same pair of guide rods.