Clutch: Description and Operation

Clutches

There are 4 wet type multi disc clutches (low clutch, high clutch, reverse clutch and direct clutch).

Each clutch has two primary rotating parts (the clutch drum and the clutch hub). Power transmission is effected and controlled by these two parts.

The clutch drum and hub are connected to a clutch plate. Pressure applied to the clutch plate results in power transfer. When this pressure is released from the clutch plate, power does not transfer.

The clutch plates at the clutch drum side function as the driven plates. The clutch plates at the clutch hub side function as the drive plates. The drive plates have friction materials on the faces.

Clutch engagement occurs when oil pressure is applied to the piston in the clutch drum. The dish plate acts as a cushion to prevent sudden and violent force applied to the clutch plates, which may causes a rough clutch engagement.

The retaining plate is attached to the driven plate. The retaining plate also serves as a spacer when the clutch is disengaged. It ensures specified clutch clearance.

The piston is returned by return spring forces to ordinal position when the oil pressure is removed through the drain hole. As a result the clutch is disengaged.

The check ball is forced to seal the oil circuit by oil pressure against the oil input hole when the clutch is engaged. When the clutch is released the check ball moves back from the input hole to open the circuit and air is led into the oil chamber. This prevents residual oil pressure build-up in the clutch drum.

The clutch drum and the clutch hub are connected to the planetary gears respectively. Planetary gear rotation acts as the controlling element of the clutch.

Cancel Force Cover





Low Clutch

High Clutch





The JF506E automatic transmission is equipped with the centrifugal oil pressure cancel room in low clutch and high clutch.

The centrifugal oil pressure cancel room improves clutch release time by applying force to the low clutch and the high clutch.

This system improves operating performance of the piston compared with the check ball system.

The piston returns to the original position by centrifugal force that is kept at the pressure room located at the other side of the piston cylinder.

Therefore, the response of the clutch release operation is improved and quick gear change is obtained.

One Way Clutches
The transmission uses two one way clutches.

Low One Way Clutch
The front planetary carrier is fixed by the inner race, which runs free during 1st gear operation.

Reduction One Way Clutch
The reduction sun gear is fixed by the inner race which runs free during 1st, 2nd, 3rd and 4th gear operations.

Roller-Type One-Way Clutch








Normally, rollers are energized to the narrower section via a spring. Therefore, in the direction where the rollers are engaged between the cam and inner race they are united to transmit torque. In the reverse direction, because the rollers move in the direction where the clearance is larger, clearances occur between races and the inner and outer races can rotate to each other.

Sprag-Type One-Way Clutch





Note the difference between sprag diameters "A" and "B" If the inner race tries to turn toward the left, radius "B" (longer than gap "C") firmly locks the sprag to prevent the sprag from moving to the left.