Synchromesh automatic transmission

• US 20080210034A1
• Filed: 02/28/2008
• Published: 09/04/2008
• Est. Priority Date: 03/01/2007
• Status: Active Grant

• Current Assignee: Mitsubishi Jidosha Engineering Kabushiki Kaisha, Mitsubishi Jidosha Kogyo Kabushiki Kaisha
• Original Assignee: Mitsubishi Jidosha Engineering Kabushiki Kaisha
• Inventors: Matsumoto, Koji, Murakami, Tsuyoshi, Yamaura, Hiroki, Komori, Katsuhiro
• Granted Patent: US 7,762,154 B2
• Time in Patent Office: Days
• US Class Current: 74/335
• 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 2063/208 using two or more selecting fingers
• CPC Class Codes: F16H 2200/0052 the gear ratios comprising six forward speeds
• CPC Class Codes: F16H 3/006 power being selectively transmitted by either one of the parallel flow paths
• CPC Class Codes: F16H 61/32 Electric motors actuators or related electrical control means therefor
• 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 63/20 with preselection and subsequent movement of each final output mechanism by movement of the final actuating mechanism in two different ways, e.g. guided by a shift gate
• CPC Class Codes: F16H 63/3408 the locking mechanism being moved by the final actuating mechanism
• CPC Class Codes: F16H 63/36 Interlocking devices
• CPC Class Codes: Y10T 74/19233 Plurality of counter shafts
• CPC Class Codes: Y10T 74/19251 Control mechanism
• CPC Class Codes: Y10T 74/20098 Separate actuator to disengage restrictor
• CPC Class Codes: Y10T 74/20104 Shift element interlock

Abstract

A synchromesh automatic transmission includes a lug lock portion which is engaged with a shift lug separately from a shift finger and enables a shift fork to be controlled so as to be located at a neutral position, a shift selector mechanism which achieves a target shift stage by engaging the shift finger with the shift lug of the shift fork corresponding to the target shift stage and displacing this shift fork in a shift direction, and an interlock mechanism which controls a shift fork that is different from the target shift stage so as to be located at a neutral position by displacing the lug lock portion following movement of the shift finger in a selection direction and engaging this lug lock portion with the shift lug of the shift fork that is different from the target shift stage.

Claims

1. A synchromesh automatic transmission comprising:

a plurality of shift forks for changing a shift stage;

a plurality of shift lugs which are provided to drive said each shift fork and are aligned in a row;

a shift finger which is engaged with one of said plurality of shift lugs and displaces a corresponding shift fork to a shift position; and

a selector shaft which is elongated along the row of the shift lugs, supports the shift finger so as to be displaced in a selection direction and enables the shift finger to be selectively engaged with one of said plurality of shift lugs,

wherein the synchromesh automatic transmission further comprises;

a lug lock portion which is engaged with the shift lug separately from the shift finger and enables the shift fork to be controlled so as to be located at a neutral position;

a shift selector mechanism which achieves a target shift stage by engaging the shift finger with the shift lug of the shift fork corresponding to the target shift stage and displacing this shift fork in a shift direction; and

an interlock mechanism which controls a shift fork that is different from the target shift stage so as to be located at a neutral position by displacing the lug lock portion following movement of the shift finger in a selection direction and engaging this lug lock portion with the shift lug of the shift fork that is different from the target shift stage.

2. The synchromesh automatic transmission according to claim 1,

wherein the lug lock portion is arranged on an interlock shaft that is elongated substantially in parallel with the selector shaft.

3. The synchromesh automatic transmission according to claim 1,

wherein the interlock mechanism engages the lug lock portion with the shift lugs of all shift forks other than the target shift stage.

4. The synchromesh automatic transmission according to claim 1, further comprising:

a twin clutch transmission mechanism having driving gears of respective shift stages arranged on a plurality of input shafts that enable to selectively input power from an engine while dividing the shift stages into predetermined shift stage groups,

wherein the interlock mechanism allows the lug lock portion to be engaged with a shift lug of a shift fork that belongs to the same group as the target shift stage but is different from the target shift stage.

5. The synchromesh automatic transmission according to claim 4, further comprising:

a twin clutch transmission mechanism having driving gears of respective shift stages arranged on a plurality of input shafts that enable to selectively input power from an engine while dividing the shift stages into predetermined shift stage groups,

wherein the interlock mechanism allows the lug lock portion to be engaged with the shift lugs of all shift forks that belong to the same group as the target shift stage and are other than the target shift stage.

6. The synchromesh automatic transmission according to claim 1,

wherein the shift lugs have lug members having groove portions and these lug members are aligned in series with their groove portions facing each other, and

the lug lock portion includes a tabular piece body which stops within the groove portion of the shift lug of the shift fork that is different from the target shift stage when the shift finger is arranged on the shift lug of the target shift stage and a taper face which is formed on end faces on the opposite sides in the selection direction of this piece body and returns the shift lug to the neutral position when the shift lug is made in a shift state.

7. The synchromesh automatic transmission according to claim 4,

wherein the shift lugs have lug members having groove portions and these lug members are aligned in series with their groove portions facing each other, and

the lug lock portion includes a tabular piece body which stops within the groove portion of the shift lug of the shift fork that is different from the target shift stage when the shift finger is arranged on the shift lug of the target shift stage and a taper face which is formed on end faces on the opposite sides in the selection direction of this piece body and returns the shift lug to the neutral position when the shift lug is made in a shift state.

8. The synchromesh automatic transmission according to claim 1,

wherein the shift lugs have lug members having groove portions and these lug members are aligned in series with their groove portions facing each other, and

the lug lock portion includes a piece body which stops within the groove portion of the shift lug of the shift fork that is different from the target shift stage when the shift finger is arranged on the shift lug of the target shift stage and a conically-shaped face which is formed on end faces on the opposite sides in the selection direction of this piece body and returns the shift lug to the neutral position when the shift lug is made in a shift state.

9. The synchromesh automatic transmission according to claim 4,

wherein the shift lugs have lug members having groove portions and these lug members are aligned in series with their groove portions facing each other, and

the lug lock portion includes a piece body which stops within the groove portion of the shift lug of the shift fork that is different from the target shift stage when the shift finger is arranged on the shift lug of the target shift stage and a conically-shaped face which is formed on end faces on the opposite sides in the selection direction of this piece body and returns the shift lug to the neutral position when the shift lug is made in a shift state.