Automatic transmission with passages connecting apply and cancel chambers

An automatic transmission having a plurality of friction elements, one of the friction elements being engaged and another one of the friction elements being disengaged during a shifting operation, the friction elements being disposed around a transmission shaft drivingly connected to an engine crankshaft, the automatic transmission comprising;

• a piston pushing the one friction element for the engagement;
• means defining a first apply chamber to which operating pressure is applied to stroke said piston for the engagement of the one friction element;
• means defining a cancel chamber to which disengagement pressure for disengaging the one friction element is applied, said cancel chamber being disposed opposite to said first apply chamber with respect to said piston, said cancel chamber being formed such that an outer diameter of a pressure receiving surface of said cancel chamber is the same as that of said first apply chamber;
• means defining a second apply chamber to which engagement pressure for engaging the another friction element to be engaged is applied;
• means defining a passage which communicates with said cancel chamber and said second apply chamber;
• wherein a friction element of the plurality of the friction elements is splined between a drum and a hub, the friction element being engaged by the pushing of a piston to apply engagement pressure to an apply chamber, a cancel chamber defined by the piston and a partition wall being disposed opposite to the apply chamber relative to the piston and formed to cancel a piston pushing force caused by a centrifugal force in the first apply chamber by a pushing force caused by a centrifugal force in the cancel chamber, and
• said automatic transmission further comprising means defining a clutch lubrication passage between the partition wall and the hub for supplying lubricant to the friction element and
• means defining a passage which communicates with the first apply chamber and said clutch lubrication passage.

An automatic transmission having a plurality of friction elements, one of the friction elements being engaged and another of the friction elements being disengaged during a shifting operation, the friction element being disposed around a transmission shaft drivingly connected to an engine crankshaft, the automatic transmission comprising:

• a clutch having a clutch piston pushing the one friction element for the engagement;
• means defining a first apply chamber to which operating pressure is applied to stroke said piston for the engagement of the one friction element;
• means defining a cancel chamber to which disengagement pressure for disengaging the one friction element is applied, said cancel chamber being disposed opposite to said first apply chamber with respect to said piston, said cancel chamber being formed such that an outer diameter of a pressure receiving surface of said cancel chamber is the same as that of said first apply chamber;
• means defining a second apply chamber to which engagement pressure for engaging the another friction element to be engaged is applied;
• means defining a passage communicates with said cancel chamber and said second apply chamber;
• wherein the automatic transmission has a gear train which is provided with a plurality of rotating members;
• the automatic transmission further comprising a cylindrical drum connected with one of the rotating members;
• said clutch connecting the one rotating member to another of the rotating members said clutch being disposed inside of said cylindrical drum;
• a brake by which the one rotating member is selectively stopped, said brake being disposed outside of said cylindrical drum;
• and
• said clutch piston for engaging said clutch by its pushing operation, said clutch piston being generally coaxial with said brake such that said clutch piston and said brake are in contact with a surface perpendicular to an axis of the automatic transmission.