Abstract: Second and third clutches are axially aligned so that the back side of the second clutch and the front side of the third clutch oppose each other, and a first clutch is positioned radially inward of the second and third clutches. Further, a clutch drum is extended so as to be used in common by the second and third clutches, the second clutch is engaged and disengaged from the axial front side by a second piston of a second oil pressure actuator, and the third clutch is engaged and disengaged from the axial rear side by a third piston of a third oil pressure actuator. The first through third clutches are positioned in a compact manner and can be independently operated.

Abstract: Second and third clutches are axially aligned so that the back side of the second clutch and the front side of the third clutch oppose each other, and a first clutch is positioned radially inward of the second and third clutches. Further, a clutch drum is extended so as to be used in common by the second and third clutches, the second clutch is engaged and disengaged from the axial front side by a second piston of a second oil pressure actuator, and the third clutch is engaged and disengaged from the axial rear side by a third piston of a third oil pressure actuator. The first through third clutches are positioned in a compact manner and can be independently operated.

Abstract: A compact automatic transmission for a vehicle capable of preventing increase in relative rotational speed between shift elements. A planetary gear unit is provided with a sun gear to which rotation of an input shaft is input, a carrier that can be stopped from rotating, and a ring gear for outputting, to a planetary gear set, rotation that is reduced in speed relative to that of the input shaft. A clutch is connected/disconnected, the input shaft and the sun gear are appropriately connected/disconnected, and the carrier is appropriately stopped/unstopped by a brake and a one-way clutch. This prevents relative rotational speed between shift elements of the gear unit that does not participate in a shifting operation from excessively increasing. When the clutch is disposed between the input shaft and the sun gear, the torque capacity of the clutch can be reduced as compared with the case where it is disposed between the gear unit and the gear set.

Abstract: A compact automatic transmission for a vehicle capable of preventing increase in relative rotational speed between shift elements. A planetary gear unit is provided with a sun gear to which rotation of an input shaft is input, a carrier that can be stopped from rotating, and a ring gear for outputting, to a planetary gear set, rotation that is reduced in speed relative to that of the input shaft. A clutch is connected/disconnected, the input shaft and the sun gear are appropriately connected/disconnected, and the carrier is appropriately stopped/unstopped by a brake and a one-way clutch. This prevents relative rotational speed between shift elements of the gear unit that does not participate in a shifting operation from excessively increasing. When the clutch is disposed between the input shaft and the sun gear, the torque capacity of the clutch can be reduced as compared with the case where it is disposed between the gear unit and the gear set.

Abstract: A hydraulic actuator has a hub, an annular recessed groove on the inner peripheral surface of the hub and an oil chamber, from which a slanted oil channel is pierced to the bottom of the recessed groove. Accordingly, there is no need for the slanted oil channel to extend to the inner peripheral surface of the hub, by which the slanted oil channel can save its length. The oil is sent from the supply oil channel formed in the boss section to the annular recessed groove of the hub in slidable contact with the boss section, and to the oil chamber through the slanted oil channel.

Abstract: In an automatic transmission mounted on a front engine and front drive vehicle, a valve body is positioned not to be obstructed by a vehicle side subframe, and lower sections of the transaxle casing, transaxle housing and rear cover form an oil reservoir space. Also, the lower part of the front differential device is isolated from the oil reservoir space by an oil reservoir plate and a side weir formed on the transaxle housing, but oil flows partly between the isolated areas. By this structure, the oil reservoir space is formed extending generally over the lower part of the integrated casing, and, in particular, is formed from the large space below the transaxle casing and the housing.

Abstract: A sequence valve for the first brake (B.sub.1) is installed, and the forward four speed modes are attained by two solenoid valves. At in the second speed mode of D range, hydraulic pressure is applied to the second brake hydraulic servo to restrain certain rotating element through the one-way clutch. After the application to the second brake hydraulic servo is completed, then the hydraulic pressure is applied to the sequence valve for the first brake, and through the sequence valve, the hydraulic pressure is applied to the first brake hydraulic servo. Accordingly, when up shifting from the first speed mode to the second speed mode, the shifting is conducted smoothly by the engagement of the second brake, after that the first brake is engaged. When up shifting from the third speed mode to the fourth speed mode, the first brake hydraulic servo is swiftly drained by the 3-4 shift valve.

Abstract: A ring gear and an outer race of a one-way clutch are linked and secured in the axial direction. The outer peripheral section of a disk-shaped supporting member engages teeth of the ring gear and supports the ring gear, and a tapered snap ring is mounted in an indented groove with a tapered surface formed in the ring gear so that the side surface of the outer peripheral section of the support member is in intimate contact with the end surface of the outer race, and the support member is thus secured and prevented from withdrawing. An oil sump for lubricant supplied from the inner radial side is formed on the inner peripheral part of the outer race defined by the intimately contacted outer race and the support member. The ring gear of the planetary gear unit rotates when the automatic transmission actuates, and the integral support member also rotates based on the rotation of the ring gear.

Abstract: A carrier is provided with a flange-shaped carrier cover directly secured to a pinion shaft which supports a pinion, and the carrier cover is integrally formed to a countershaft by heat forging. The carrier cover is formed with a lubricant oil hole extending from the countershaft toward the pinion shaft, and the countershaft is formed with a small diameter on the side bounded by the carrier cover where the planetary gear unit is positioned, and with a large diameter on the opposite side. As a result, the countershaft has a high degree of strength and forms a compact gear unit in the axial direction. Lubricant is supplied from a lubricant oil hole in the center of the shaft to a lubricant oil hole formed in the carrier cover, and is forcedly fed to the support surface of the pinion through oil holes in the pinion shaft. The axial force from the counterdriven gear is applied to a thrust bearing between the hub and the carrier cover, and the axial force is backed up by the large diameter section of the shaft.

Abstract: A stator shaft is press-fitted and secured to the inner peripheral surface of a pump cover positioned between a torque converter and a automatic transmission mechanism section. Bushings are fitted to a part opposing the press-fit section with reference to the outer peripheral surface of an input shaft fabricated with a uniform diameter with the exception of the rear end part, and to a part slightly forward of the above-mentioned part, respectively, and an oil channel for the torque converter feed pressure is formed between the two bushings. As a result, the forward end section of the input shaft is supported in a freely rotatable manner by the bushings which are relatively close to each other. The torque converter feed pressure is fed from an oil channel formed in the pump cover to an oil channel between the two bushings, and through the cross hole and the center hole formed in the input shaft to the torque converter.

Abstract: The first and second emergency control valves are a back up device in case all solenoid valves are in failure (non electrified). When the first and second solenoid valves are all off due to wire disconnection and the like in case the manual valve is at the 3 range, a 1-2 shift valve is constrained by the first emergency control valve, so that the hydraulic control device becomes the third speed mode. In case t#e manual shift lever is at the 2 range and a 2-3 shift valve, the 2-3 shift valve are constrained by the first and the second emergency control valves, so that the hydraulic control device becomes the second speed mode. In case the manual shift lever is at the 1 range, the first emergency control valve is constrained, and the 2-3 shift valve is constrained by the second emergency control valve, so that the hydraulic control device becomes the first speed mode. When the manual valve is at the D range, the fourth speed mode is attained in case the first and second solenoid valves are all off.

Abstract: A plurality of oil channels formed in a casing is communicated with a single rotating hydraulic actuator. The casing comprises a transaxle casing on which a valve body is disposed, and a rear cover is fixed to the transaxle casing. The oil channels extend outwardly from a boss section in the casing and are radially arranged in a single plane of the rear cover. Oil from the hydraulic actuator is instantly exhausted through oil holes of an inner drum, an annular indented groove of the boss section, indented portions of sector shape and the oil channels.

Abstract: A thrust washer has a protrusion which is formed with a projecting pawl. The rotating member is formed with a through hole, into which the protrusion of the thrust washer is inserted, such that the pawl is projected out on the opposed surface remote from the thrust washer of the rotating member, whereby the upstanding surface of the pawl is used as a stop means. Thus, the thrust washer is positively secured to the rotating member.

Abstract: An orifice is installed on an oil passage to a hydraulic servo for a direct clutch. In forward high speed running, a line pressure from the D range port of a manual valve is supplied to the hydraulic servo through an oil passage used for forward high speed running and a three way cock (non manual type). Then comparatively large amount of oil is supplied to the servo in accordance with the high speed running. In reverse running, the line pressure from the R range port of the manual valve is supplied to the servo through the orifice and the three way cock. Consequently, comparatively small amount of oil is supplied to the hydraulic servo.

Abstract: In an automatic transmission provided with an automatic transmission mechanism section with a planetary gear unit and a torque converter, a snap ring groove is defined by an annular flange section for a stator shaft and a pump cover, and the reaction from a return spring is borne in the annular flange section. A stator shaft, which bears the stator reaction of a torque converter, is engagingly secured in a center hole section of an oil pump assembly, an annular flange section projecting to the radially outer side is formed at one end of the stator shaft, the snap ring groove is defined from the annular flange section and an annular recessed section of the oil pump assembly to receive the snap ring, and a receiving member for the return spring of the hydraulic actuator is maintained by the snap ring installed in the snap ring groove.

Abstract: In a dual planetary gear of an automatic transmission, tooth surface pressure generated at a relatively short pinion is decreased and distributed since the pinion is formed as a pair of pinions. These pinions can be pinions which mesh with a sun gear or pinions which mesh with a ring gear and a single first pinion. Torque exerted on the ring gear (or the sun gear) is transmitted to the sun gear (or the ring gear) through one point of contact (or two) between the sun gear and one pinion (or a pair of pinions) and the ring gear and two points of contact (or one) between a pair of pinions (or one pinion) and the ring gear.

Abstract: A thick-walled, narrow-width oil strainer positioned in a space formed between the contact surfaces of the transaxle casing and transaxle housing of an automatic transmission is disclosed. Both the upper body and lower bodies of the oil strainer are constructed with an angled cross section to provide a deep suction section and a deep discharge section. A filter element is supported by being interposed between the peripheral edge sections and supporting bosses of the two bodies, and is slanted at a prescribed angle with respect to the suction section and the discharge section. The strainer is mounted with the right and left openings of the discharge section interposedly supported by the pump body and the transaxle casing, so that the oil discharged from the valve body is sucked directly into the pump through the suction section, and the oil in the oil sump is sucked into the pump through the filter element.

Abstract: In an automatic transmission mechanism for an automatic transmission mounted on automobiles having two planetary gears, a one-way clutch functioning in shifting up and down between third and fourth speed is laid, and a fourth clutch is laid between the one-way clutch and an input member, and a hydraulic actuator to operate both a third clutch and a fourth clutch is laid, whereby the one-way clutch functioning in shifting up and down between third and fourth speed, plural clutches laid in the automatic transmission mechanism, the third clutch, the fourth clutch and the actuators for these clutches are in all laid in end portion of the automatic transmission mechanism.