Abstract: An oil temperature responsive hydraulic control system for an automatic transmission includes a hydraulic servo for applying/releasing a frictional engagement element; a pressure regulator valve for regulating oil pressure fed to the hydraulic servo; and a signal pressure oil passage for applying a pressure regulating signal pressure to the pressure regulator valve. A control valve is arranged in the signal pressure oil passage for changing the effective diameter of the signal pressure oil passage responsive to change in oil temperature.

Abstract: An optical disc for a key physically stores first security information. The optical disc logically stores second security information. The first security information is equal to security information physically recorded on a legitimate optical disc. The second security information is equal to security information logically recorded on the legitimate optical disc.

Abstract: An optical disc on which a number of spiral trains of regular pits and at least one train of irregular pits are formed. The regular pits of each of the trains is arranged symmetrically with respect to the center of a track. Each of the irregular pits has a predetermined shape different from a shape of each of the regular pits. An arrangement of the train of the irregular pits being differs from an arrangement of each of the trains of the regular pits. A tracking error signal being obtained from the train of the irregular pits. An irregular pit can not be copied even when a normal optical disc containing such an irregular pit is copied by performing a conventional copying method. Thus, an illegal copy disc can be discriminated from a normal optical disc by checking whether or not an irregular pit is included in an optical disc to provide good copy protection by easily detecting an illegal copy disc.

Abstract: An optical disc has a sequence of pits which extends along a track. The pit sequence represents a recorded signal divided into data blocks. The pit sequence includes a normal pit train and an unusual pit train. The normal pit train is symmetrical with respect to a center of the track. The unusual pit train is different from the normal pit train in at least one of shape and pit arrangement. The unusual pit train is at a position having a predetermined relation with the data blocks.

Abstract: A hydraulic control circuit for an automatic transmission which has a plurality of hydraulic type frictional engagement elements for switching gear stages and a lockup clutch juxtaposed to a hydraulic power transmission device for transmitting engine power to the gearing. The hydraulic control circuit includes a lockup relay valve for switching oil pressure between an application side oil chamber and a release side oil chamber of the lockup clutch to apply and release the lockup clutch and a lockup switching valve for switching the lockup relay valve. A lockup control valve functions to increase the pressure difference between the application side oil chamber and the release side oil chamber at the time of application of the lockup clutch, as a signal pressure rises. A transient pressure control valve controls the transient pressure of a hydraulic frictional engagement element in accordance with the signal pressure.

Abstract: An automatic transmission for an automotive vehicle has a plurality of friction devices for selectively coupling a number of rotary elements in a planetary gear mechanism to one another, and a hydraulic circuit for controlling changeover of the friction devices. The hydraulic circuit includes a regulator valve for generating line pressure, a manual valve for selectively changing over the line pressure to the hydraulic circuit, a plurality of shift solenoids for directly controlling engaging hydraulic pressure of the friction devices by duty control when a shift is made, and a plurality of relay valves controlled by the solenoid valves, wherein the solenoid valves are duty-controlled independently of one another. With such an arrangement, one accumulator is sufficient and the number of valves can be reduced, so that the valve body can be made more compact. In addition, highly precise shock control is possible with regard to all shift conditions.

Abstract: A brake band drum for a planetary gear-type automatic transmission in which a clutch is formed inside a press-manufactured planetary gear input member coupled to a press-manufactured clutch cylinder and one member of a planetary gear mechanism, and a band brake is arranged on the outer peripheral side of the clutch cylinder or planetary gear input member, characterized in that the clutch cylinder or planetary gear input member is fitted by being splined, and an engaging surface of the band brake is formed on an outer peripheral surface of the clutch cylinder or planetary gear input member. Thus, the brake band drum is formed by fitting the brake band drum and clutch cylinder together. This makes it possible to dispense with electron beam welding. As a result, costs and weight can be reduced.

Abstract: An automatic transmission having a one-way brake in which an outer race is fixed to a rotational member of a planetary gear unit or to a transaxle case and, conversely, an inner race is fixed to the transaxle case or the rotational member of the planetary gear unit, characterized in that the rotational member is provided with an oil infeed plate co-rotatable therewith. Oil dispersed from the input shaft of the transmission is introduced to the one-way brake by pressure produced by the centrifugal force of the rotating oil infeed plate. Thus, burn-out of the one-way clutch is prevented since the clutch is sufficiently lubricated at the time of overrun.

Abstract: A parking mechanism for a transmission, comprising: a coupling member engageable simultaneously with two gears for different gear positions of the transmission when a change device provided besides a driver's seat is set in a "parking" position.