Synchronizer-mechanism-equipped transmission

Patent metadata

Field	Value
Publication number	US-2016290441-A1
Application number	US-201615078117-A
Country	US
Kind code	A1
Filing date	Mar 23, 2016
Priority date	Mar 30, 2015
Publication date	Oct 6, 2016
Grant date	—

Abstract

A synchronizer-mechanism-equipped transmission capable of moving tips of sleeve teeth and ring teeth away from butting each other by moving a synchronizer sleeve with biasing means even if the tips of the sleeve teeth and ring teeth are in contact when actuator driving stops. When sleeve teeth of a synchronizer sleeve that moves during gear shifting are located at a first synchronization position where the sleeve teeth begin to come into contact with ring teeth, a pressing member of a detent mechanism is in contact with a pre-gear-shifting detent recessed portion of a star cam.

First claim

What is claimed is:

1 . A synchronizer-mechanism-equipped transmission comprising:
a gear transmission mechanism having a plurality of driving transmission gears pivotally supported on a main shaft and a plurality of driven transmission gears pivotally supported on a counter shaft, the driving transmission gears and the driven transmission gears constantly meshing with each other for each gear ratio; a synchronizer mechanism in which ring teeth, formed on a synchronizer ring, come between gear dog teeth and sleeve teeth, the gear dog teeth being formed on a first transmission gear that is pivotally supported in a relatively rotatable manner on at least one of the main shaft and the counter shaft, each being a rotating shaft, the sleeve teeth being formed on a second transmission gear or a synchronizer sleeve as a moving sleeve that is pivotally supported on the rotating shaft in such a manner so as to be restricted in relative rotation and axially movable, and in which, during gear shifting, the synchronizer sleeve moves and causes the sleeve teeth to come into contact and mesh with the ring teeth first and then come into contact and mesh with the gear dog teeth so that the synchronizer sleeve and the first transmission gear are synchronized and coupled together; a transmission drive mechanism including:
a shift drum driven to rotate by an actuator; and
a shift fork guided by a lead groove of the shift drum to move axially as a result of rotation of the shift drum, the shift fork engaging with the synchronizer sleeve so as to move the synchronizer sleeve; and
a detent mechanism having a star cam on an outer circumferential end surface of which an uneven cam surface is formed, detent recessed portions associated with gear positions and projecting portions being formed on the uneven cam surface in such a manner so as to alternate continuously, the star cam being provided to rotate integrally with the shift drum, biasing means causing a pressing member to come into contact with and press the uneven cam surface of the star cam and causing the pressing member to slip into a required detent recessed portion, the shift drum being rotated and biased together with the star cam so as to be positioned; wherein when the sleeve teeth of the synchronizer sleeve that moves during gear shifting are located at a first synchronization position where the sleeve teeth begin to come into contact with the ring teeth, the pressing member of the detent mechanism is in contact with a pre-gear-shifting detent recessed portion of the star cam.

2 . The synchronizer-mechanism-equipped transmission of claim 1 , wherein when the sleeve teeth of the synchronizer sleeve that moves during gear shifting are located at a second synchronization position where the sleeve teeth begin to come into contact with the gear dog teeth, the pressing member of the detent mechanism is in contact with a post-gear-shifting detent recessed portion of the star cam.

3 . The synchronizer-mechanism-equipped transmission of claim 1 , wherein the pressing member of the detent mechanism is a roller, pivotally supported at a tip of a detent arm that is biased by the biasing means for coming into contact with and presses the uneven cam surface of the star cam.

4 . The synchronizer-mechanism-equipped transmission of claim 2 , wherein the pressing member of the detent mechanism is a roller, pivotally supported at a tip of a detent arm that is biased by the biasing means for coming into contact with and presses the uneven cam surface of the star cam.

5 . The synchronizer-mechanism-equipped transmission of claim 1 , wherein the sleeve teeth are tapered at both ends thereof in a longitudinal direction by a pair of chamfered surfaces wherein the chamfered surfaces intersect each other at an obtuse angle.

6 . The synchronizer-mechanism-equipped transmission of claim 5 , wherein an end portion of each of the ring teeth on a side of the sleeve teeth is formed tapered by chamfered surfaces.

7 . The synchronizer-mechanism-equipped transmission of claim 5 , wherein an end portion of each of the gear dog teeth on a side of the sleeve teeth is formed tapered by chamfered surfaces.

8 . The synchronizer-mechanism-equipped transmission of claim 3 , and further including a pawl ratchet mechanism operatively connected to a master arm wherein swinging the master arm rotates the shift drum.

9 . The synchronizer-mechanism-equipped transmission of claim 8 , wherein the pawl ratchet mechanism includes a ratchet input member, a ratchet output member and a pair of pawls, wherein a protrusion formed on the ratchet input member is fitted for freely sliding into an elongated opening formed in a swinging tip portion of the master arm.

10 . The synchronizer-mechanism-equipped transmission of claim 9 , wherein the ratchet output member rotates integrally with the shift drum with the pawls being incorporated between the outer circumference of the ratchet input member and an inner circumference of the ratchet output member.

11 . A synchronizer-mechanism-equipped transmission comprising:
a gear transmission mechanism having a plurality of driving transmission gears pivotally supported on a main shaft and a plurality of driven transmission gears pivotally supported on a counter shaft; a synchronizer mechanism wherein ring teeth, formed on a synchronizer ring, come between gear dog teeth and sleeve teeth, the gear dog teeth being formed on a first transmission gear that is pivotally supported in a relatively rotatable manner on at least one of the main shaft and the counter shaft, each being a rotating shaft, the sleeve teeth being formed on a second transmission gear or a synchronizer sleeve as a moving sleeve that is pivotally supported on the rotating shaft in such a manner so as to be restricted in relative rotation and axially movable; said synchronizer sleeve moves and causes the sleeve teeth to come into contact and mesh with the ring teeth first and then come into contact and mesh with the gear dog teeth so that the synchronizer sleeve and the first transmission gear are synchronized and coupled together during gear shifting; a transmission drive mechanism including:
a shift drum driven to rotate by an actuator; and
a shift fork guided by a lead groove of the shift drum to move axially as a result of rotation of the shift drum, the shift fork engaging with the synchronizer sleeve so as to move the synchronizer sleeve; and
a detent mechanism comprising:
a star cam on an outer circumferential end surface of which an uneven cam surface is formed;
detent recessed portions associated with gear positions and
projecting portions being formed on the uneven cam surface so as to alternate continuously;
biasing means causing a pressing member to come into contact with and press the uneven cam surface of the star cam and causing the pressing member to slip into a required detent recessed portion;
said star cam being provided to rotate integrally with the shift drum, the shift drum being rotated and biased together with the star cam so as to be positioned;
wherein when the sleeve teeth of the synchronizer sleeve that moves during gear shifting are located at a first synchronization position where the sleeve teeth begin to come into contact with the ring teeth, the pressing member of the detent mechanism is in contact with a pre-gear-shifting detent recessed portion of the star cam.

12 . The synchronizer-mechanism-equipped transmission of claim 11 , wherein when the sleeve teeth of the synchronizer sleeve that moves during gear shifting are located at a second synchronization position where the sleeve teeth begin to come into contact with the

Assignees

• Honda Motor Co Ltd

Inventors

• Tsukada Yoshiaki
• Kanno Yoshihisa
• Nakamura Kazuhiko
• Kojima Hiroyuki
• Ozeki Takashi
• Takamoto Hiroshi

Classifications

• F16H2063/3093

  Final output elements, i.e. the final elements to establish gear ratio, e.g. coupling sleeves or other means establishing coupling to shaft · CPC title

• F16H3/006

  power being selectively transmitted by parallel flow paths, e.g. dual clutch transmissions · CPC title

• F16D23/06

  and a blocking mechanism preventing the engagement of the main clutch prior to synchronisation · CPC title

• F16H3/091 Primary

  including a single countershaft · CPC title

• F16D11/00

  Clutches in which the members have interengaging parts (arrangements for synchronisation F16D23/02) · CPC title