In a drive unit particularly for motor vehicles comprising
- (a) a clutch assembly (16) having an axis and comprising
- (aa) a first rotor unit (1, 5, 7);
- (ab) a second rotor unit (2, 3);
- (ac) frictional engagement means (2a) on said first rotor unit (1, 5, 7) and said second rotor unit, respectively;
- (ad) biasing means (6) mounted on said first rotor unit (1,5,7) for common rotation therewith and effecting engagement of said frictional engagement means (2a);
- (ae) clutch release means 6a) mounted for common rotation with said first rotor unit (1, 5, 7) and being axially movable between a clutch engagement position (FIG. 1) and a clutch disengagement position, said clutch engagement position being subject to axial shift in dependency on the wear condition of said frictional engagement means (2a);
- (b) a gear box unit comprising
- (ba) a gear box housing (8) and
- (bb) an input shaft (4) having an axis coincident with said axis of said clutch assembly (16) and being connected for common rotation with said second rotor unit (2, 3);
- (c) an annular release force transmission unit (13, 15, 14, 9) surrounding said input shaft (4) and having an axis coincident with the axis of said clutch assembly (16), said annular release force transmitting unit (13, 15, 14, 9) comprising
- (ca) a first annular release force transmitting member (13) adjacent said clutch assembly (16) and engaged for common axial movement and common rotation with said clutch release means (6a),
- (cb) a second annular release force transmitting member (14) adjacent said gear box housing (8) and mounted--under normal operational conditions--for common axial movement and common rotation with said first release force transmitting member (13) and
- (cc) a clutch release bearing assembly (9) comprising
- (cca) a first bearing member (13) connected for common axial and rotational movement with said second release force transmitting member (14) and
- (ccb) a second bearing member (10) mounted for common axial movement with said first bearing member (12) and for free rotation with respect to said first bearing member, said second bearing member (10) being connected to a non-rotating clutch actuating unit (19) for axial movement along said axis of said clutch assembly (16);
- (d) frictional input shaft braking means (40) comprising
- (da) a braking disc member (18) mounted for rotation with said input shaft (4);
- (db) a braking face (8a) stationary with respect to said bear box housing (8);
- (dc) a brake disc member engagement face (17a) mounted on said clutch actuating unit (19) for common axial movement therewith in view of pressing said braking disc member (18) into braking engagement with said braking face (8a) in response to movement of said clutch release means (6a) towards or beyond said clutch disengagement position;
- (e) wear compensating means compensating for the axial shift of said brake disc member engagement face (17a) resulting from wear of said frictional engagement means (2a);
- the improvement comprising thread means (15) having an axis coincident with said axis of said clutch assembly (16) and interconnecting said first release force transmitting member (13) and said second release force transmitting member (14), and frictional torque supporting means (21, 24, 23) frictionally supporting said second release force transmitting member (14) in said clutch engagement position of said clutch release means (6a) aqainst rotation with said first release force transmitting member (13) in response to axial shift of said clutch engagement position of said clutch release means (6a), said clutch engagement position of said clutch release means (6a) being more remote from said gear box housing (8) than said clutch disengagement position;
- said clutch engagement position of said clutch release means (6a) being shifted axially away from said gear box housing (8) in response to increasing wear of said frictional engagement means (2a);
- said braking disc member (18) of said frictional input shaft braking means (40) being located axially between said stationary braking face (8a) directed towards said clutch assembly (16) and said brake disc member engagement face (17a) directed towards said gear box housing (8);
- said frictional torque supporting means (21, 24, 23) comprising a support disc member (21) mounted for common rotation with and axial movement with respect to said second release force transmitting member (14) and being located axially between a torque supporting face (24) of said nonrotating clutch actuating unit (19) and an abutment face (23) of said first rotor unit (1, 5, 7), which abutment face (23) is axially fixed with respect to said first rotor unit (1, 5, 7) and mounted for free rotation with respect thereto;
- said thread means (15) being of such sense that said second release force transmitting member (14) is threaded towards said gear box housing (8) when said support disc member (21) is engaged by said torque supporting face (24) and said abutment face (23) in response to axial shift of said clutch engagement position of said clutch release means (6a) away from said gear box housing (8).