Automatic transmission and centrifugal balance adjustment method for automatic transmission

A centrifugal balance adjustment method for an automatic transmission which includes a clutch that comprises a cylindrical drum section;

• a cylindrical hub section that opposes the drum section;
• a friction plate that is engaged in an axially slidable manner between the drum section and the hub section;
• a piston that presses the friction plate;
• a hydraulic chamber to which hydraulic oil is supplied to urge the piston in a direction toward the friction plate;
• and a cancellation chamber to which hydraulic oil is supplied to cancel a centrifugal hydraulic pressure applied to the hydraulic oil in the hydraulic chamber, the piston being interposed between the hydraulic chamber and the cancellation chamber, the drum section including communication passages that extend in a radial direction and respectively communicate with the hydraulic chamber and the cancellation chamber, the centrifugal balance adjustment method comprising:
• providing an adjustment member at an end portion on a radially inner side of the communication passage that communicates with the cancellation chamber among the communication passages, the adjustment member being configured to adjust an atmospheric air release position of the communication passage in the radial direction;
• generating the centrifugal hydraulic pressure in each of the hydraulic chamber and the cancellation chamber in a state where the adjustment member is located at a specified position on the radially outermost side;
• and
• adjusting the adjustment member toward a radially inner side so as to thereafter obtain a state where a load in a direction in which the piston presses the friction plate becomes zero.

A centrifugal balance adjustment method for an automatic transmission which includes a clutch that comprises a cylindrical drum section;

• a cylindrical hub section that opposes the drum section;
• a friction plate that is engaged in an axially slidable manner between the drum section and the hub section;
• and a piston that presses the friction plate;
• a hydraulic chamber to which hydraulic oil is supplied to urge the piston in a direction toward the friction plate;
• and a cancellation chamber to which hydraulic oil is supplied to cancel a centrifugal hydraulic pressure applied to the hydraulic oil in the hydraulic chamber, the piston being interposed between the hydraulic chamber and the cancellation chamber, the drum section including communication passages that extend in a radial direction and respectively communicate with the hydraulic chamber and the cancellation chamber, the centrifugal balance adjustment method comprising:
• providing an adjustment member at an end portion on a radially inner side of the communication passage that communicates with the cancellation chamber among the communication passages, the adjustment member being configured to adjust an atmospheric air release position of the communication passage in the radial direction;
• measuring an outer diameter of the hydraulic chamber, an inner diameter of the hydraulic chamber, a radially innermost position of the communication passage that communicates with the hydraulic chamber, and an outer diameter of the cancellation chamber as measurements;
• when the centrifugal hydraulic pressure is generated in each of the hydraulic chamber and the cancellation chamber, calculating, from the measurements, a radial position of the adjustment member such that an engagement-side load matches a disengagement-side load, the engagement-side load being applied to the piston from the hydraulic chamber side toward the cancellation chamber side, and the disengagement-side load being applied to the piston from the cancellation chamber side toward the hydraulic chamber side;
• and
• adjusting the adjustment member to the calculated radial position in advance.