Why do we use a twin countershaft transmission in a heavy duty truck?

The primary objective of a twin countershaft transmission is to ensure that the multiple countershafts each carry an equal share of the total torque being transmitted from the input shaft of the transmission to the output.

What does a countershaft do in a transmission?

In a normal sliding gear transmission there are two shafts, a main shaft and a counter shaft. A counter shaft is a manual transmission shaft driven by the clutch shaft and its input gear. The counter shaft rotates in a direction counter to engine rotation.

What is the primary reason manufacturers use multiple countershaft transmissions?

Multiple-countershaft transmissions make the manufacturing process a little easier. D., p1217, multiple countershaft transmissions shorten transmission length, decrease weight, and decrease the torque load as more of the mainshaft gear teeth are used to transfer the load to the mainshaft.

What is single countershaft transmission?

A countershaft transmission comprising: a first shaft having first and second gears connected to rotate; a second shaft having a third gear rotatable and fourth and fifth gears freely rotatably mounted in intermeshing engagement with the first and second gears respectively; an idler sixth gear in intermeshing …

Which type of transmission requires double clutching between shifts?

Double-clutching (also called double de-clutching outside of the United States) is a method of shifting gears used primarily for vehicles with an unsynchronized manual transmission, such as commercial trucks and specialty vehicles.

What is the function of synchronizers in a truck transmission?

When you change gears, a slider, or shift sleeve, moves over the gear you have selected and locks it to the output shaft. A synchronizer adjusts the speed of the shaft so that the gears align more quickly as you shift.

What is an idler gear?

Definition of idler gear 1 : a gear placed between a driving and a driven gear to transfer motion without change of direction or gear ratio. 2 : a gear for support or guidance instead of power transmission.

How does a countershaft work?

Countershaft. The countershaft (aka layshaft) sits just below the output shafts. The countershaft connects directly to the input shaft via a fixed speed gear. Whenever the input shaft spins, so does the countershaft, and at the same speed as the input shaft.

What eliminates the need for double clutching techniques?

Synchronizers, or synchromesh gears, are what make shifts smooth and quick. They also eliminate the need to double clutch, or the act of using the clutch twice during each shift.

Which gear is the reverse drive gear in a cluster gear?

A shows input shaft; B the output shaft, C the Layshaft (cluster gear), and D shows the reverse gear. The forward one is called the Input shaft.

What is a cluster shaft?

: a set of gears of different sizes mounted as a unit on the same shaft.