Double disconnect transmission reverser
In accordance with an example embodiment, a transmission reverser may include a forward mode and a reverse mode. In the forward mode, a forward clutch is in the engaged condition causing an output gear to rotate with an output shaft. In the reverse mode, a reverse clutch and a disconnect clutch are in engaged conditions causing a counter shaft to rotate relative to the output shaft based upon the ratios of a first reverse gear to an idler gear and the idler gear to a second reverse gear and further causing the output gear to rotate relative to the counter shaft based upon the ratio of a third reverse gear to the output gear.
1. A transmission reverser comprising:
an output shaft receiving rotational power input and operably connected to the output of a transmission, the output shaft including a first reverse gear and an output gear;
an idler shaft including an idler gear engaged with the first reverse gear;
a counter shaft including a second reverse gear engaged with the idler gear and a third reverse gear engaged with the output gear;
a forward clutch including engaged and disengaged conditions, the forward clutch releasably connecting the output gear with the output shaft in the engaged condition;
a reverse clutch including engaged and disengaged conditions;
a disconnect device including engaged and disengaged conditions, the disconnect device releasably connecting the third reverse gear with the counter shaft in the engaged condition;
wherein the transmission reverser is operable in:
a forward mode which includes the forward clutch in the engaged condition causing the output shaft to transmit the rotational power input to the output gear; and
a reverse mode which includes the reverse clutch and the disconnect device in the engaged conditions causing the output shaft to transmit the rotational power input to the output gear through the first, second and third reverse gears, the idler gear and the counter shaft.
2. The transmission reverser of claim 1 , further comprising:
a countershaft brake including engaged and disengaged conditions, the countershaft brake impeding the rotation of the counter shaft in the engaged condition.
3. The transmission reverser of claim 1 , wherein the reverse clutch releasably connects the second reverse gear with the counter shaft in the engaged condition.
4. The transmission reverser of claim 1 , wherein the reverse clutch releasably connects the first reverse gear with the output shaft in the engaged condition.
5. The transmission reverser of claim 1 , wherein the counter shaft rotates in the same direction as the output shaft and in the opposite direction of the output gear in the reverse mode.
6. The transmission reverser of claim 1 , wherein the forward mode further includes the reverse clutch and the disconnect device in the disengaged conditions.
7. The transmission reverser of claim 1 , wherein the forward mode further includes the reverse clutch in the disengaged condition and the disconnect device in the engaged condition at slow forward speeds.
8. The transmission reverser of claim 2 , wherein the forward mode further includes the countershaft brake in the engaged condition.
9. The transmission reverser of claim 2 , wherein the reverse mode further includes the forward clutch and the countershaft brake in the disengaged conditions.
10. The transmission reverser of claim 1 , wherein the forward clutch is mounted about the output shaft.
11. The transmission reverser of claim 1 , wherein the reverse clutch is mounted about the counter shaft.
12. The transmission reverser of claim 1 , wherein the reverse clutch is mounted about the output shaft.
13. The transmission reverser of claim 1 , wherein the disconnect device is a clutch mounted about the counter shaft.
14. A method of shifting from a forward mode and a reverse mode in a transmission reverser comprising:
disengaging a countershaft brake which allows a counter shaft to rotate;
engaging a disconnect device to releasably connect a third reverse gear to the counter shaft, the third reverse gear in engagement with an output gear;
disengaging a forward clutch to disconnect the output gear from an output shaft; and
engaging a reverse clutch which causes the output shaft to transmit rotational power input to the output gear through the first, second and third reverse gears, the idler gear and the counter shaft.
15. The method of claim 14 , wherein the counter shaft rotates in the same direction as the output shaft when the reverse clutch is engaged.
16. The method of claim 14 , wherein the reverse clutch releasably connects the second reverse gear with the counter shaft in the engaged condition.
17. The method of claim 14 , wherein the reverse clutch releasably connects the first reverse gear with the output shaft in the engaged condition.
18. A method of shifting from a reverse mode and a forward mode and a forward mode in a transmission reverser comprising:
disengaging a reverse clutch which allows a counter shaft to rotate independently of an output shaft;
engaging a forward clutch to releasably connect an output gear to the output shaft causing the output gear to rotate with the output shaft;
disengaging a disconnect device to disconnect a reverse gear from the counter shaft which allows the counter shaft to rotate independently of the output gear; and
engaging a countershaft brake to impede the rotation of the counter shaft.
19. The method of claim 18 , wherein the disconnect device remains engaged and the countershaft brake remains disengaged at slow forward speeds.
20. The method of claim 18 , wherein engaging the countershaft brake impedes the rotation of the reverse clutch.