Synchronizer for a manual transmission especially for a motor vehicle

A synchronizer (1) for a manual transmission with first and second idler gears (3, 4) rotatably mounted on a transmission shaft (2);

• a synchronizer sleeve (5) is non-rotatably mounted on the transmission shaft (2) such that the synchronizer sleeve (5) can shift axially, the synchronizer sleeve (5) is releasably connectable to one of the first and the second idler gears (3, 4) via a toothed engagement and comprises a shifting flange (6) having openings (8) arranged around a periphery thereof, first and second synchronizer rings (10, 11), which can be held apart from one another by locking pins (9) distributed around a periphery, which can be inserted through the openings (8), the synchronizer comprising:
• at least one of the first and second synchronizer rings (11) has a double cone;
• the double cone (11a, 11b) is positionable in non-positive contact simultaneously with an outer coupling ring (12) that has an inner cone (12a) and an inner coupling ring (13) that has an outer cone (13a);
• and
• the inner and outer coupling rings (12, 13) can be positively connected to and axially supported against the adjacent idler gear (3).