US 11,754,148 B2
Gear transmission
Yusuke Morita, Sakai (JP); and Toshifumi Yasuda, Sakai (JP)
Assigned to Kubota Corporation, Osaka (JP)
Filed by Kubota Corporation, Osaka (JP)
Filed on May 5, 2021, as Appl. No. 17/308,339.
Claims priority of application No. 2020-168723 (JP), filed on Oct. 5, 2020.
Prior Publication US 2022/0107006 A1, Apr. 7, 2022
Int. Cl. F16H 3/089 (2006.01); F16H 63/38 (2006.01); F16H 61/682 (2006.01); F16H 63/18 (2006.01); F16H 59/10 (2006.01); F16H 61/02 (2006.01); F16H 37/02 (2006.01); B60K 17/34 (2006.01)
CPC F16H 3/089 (2013.01) [F16H 61/682 (2013.01); F16H 63/18 (2013.01); F16H 63/38 (2013.01); B60K 17/34 (2013.01); F16H 37/021 (2013.01); F16H 59/10 (2013.01); F16H 61/0297 (2013.01); F16H 2702/00 (2013.01)] 4 Claims
OG exemplary drawing
 
1. A gear transmission comprising:
a plurality of shift gears;
a plurality of shifters slidably supported on a shifter support shaft and engaged, respectively, with the plurality of shift gears;
a shift drum having a drum axis parallel with a support axis of the shifter support shaft and having, at an outer circumference portion, a plurality of shifter operational cam portions to which the plurality of shifters are engaged, respectively;
a speed changing operation shaft operably coupled to the shift drum;
a drum operating gear formed in the shift drum; and
a transmission gear formed in the speed changing operation shaft and configured to engage with the drum operating gear,
wherein, power from the speed changing operation shaft is transmitted to the shift drum via the drum operating gear and the transmission gear, and as the shift drum is rotated about the drum axis by a rotation operation of the speed changing operation shaft, the plurality of shifters are slid by the shifter operational cam portions, thereby to engage or disengage the shift gears to or from speed changing gears for setting speeds;
a detent mechanism for fixing the shift drum in position at a rotation operation position where the shift gear and one of the speed changing gears are brought into an engaged state;
wherein the detent mechanism comprises:
a positioning rotation portion formed in the shift drum;
a positioning arm disposed on the speed changing operation shaft, the positioning arm being engageable with a positioning action portion formed in the positioning rotation portion for fixing the positioning rotation portion at a rotation position at which the shift drum is brought to the rotation operation position where the engaged state is created; and
a positioning spring configured to urge the positioning arm for its engagement to the positioning action portion;
wherein the speed changing operation shaft is provided in parallel juxtaposition with the drum axis; and
wherein the positioning arm is rotatably supported by the speed changing operation shaft, and is extended from the speed changing operation shaft to the positioning rotation portion during rotation of the speed changing operation shaft.