Abstract: A multi-stage automatic transmission using a reduction planetary gear and a planetary gear set in which the respective thrust forces generated thereat are supported by a low bearing load or a low case load. The automatic transmission is provided with a reduction planetary gear, coupled to an input shaft to fix a reaction force element so as to output a reduction rotation to an output element, and a planetary gear set, that outputs a speed shift rotation upon input of the subsequent reduction rotation. During at least first gear driving, there is provided a force transmission route in which thrust forces generated at one element of the reduction planetary gear and one element of the planetary gear set, respectively, are transmitted. In that route, a torsion direction of the spiral teeth of the respective elements are set such that a direction of a thrust force of the element and a direction of the thrust force of the other element are different from each other during first gear driving.

Abstract: The level of quietness for an automatic transmission case is ensured by preventing vibration by improving the rigidity while suppressing the increase in the mass of a transmission case. In an automatic transmission case in which a valve body is attached to a case wall that covers the transmission mechanism, the rigidity of the automatic transmission case is increased by providing, in the case, an enclosing wall that projects out from the case wall and encloses the periphery of the valve body.

Abstract: To ensure durability of a one-way clutch, by reducing surface pressures applied to side bearings, a one-way clutch has end bearings that are disposed between an outer race and an inner race and that maintain concentricity between the races. In a supporting structure wherein one of the outer race and the inner race is fitted to a stationary member and the other race is fitted to a rotational member, a clearance of a fitting portion between the stationary member and one of the races is narrower than a clearance between the rotational member and the other race. A load resulting from whirling of the rotational member is absorbed by the greater clearance, and a high load resulting from radial movements of the race fitted to the stationary member and a weight of the race is supported by the stationary member. Thus, loads applied to the end bearings are reduced.

Abstract: To make it possible to maintain speeds during failures in an automatic transmission that does not have exclusive friction elements corresponding to the attainment of each speed. The hydraulic control apparatus of an automatic transmission, provided with control means 71-74 for supplying regulated pressure to each of the hydraulic servos 81-84 that are first through fourth friction elements to which hydraulic pressure is supplied from the oil path L1, and provided with switching valves (1)-(5) for cutting off the supply of hydraulic pressure to friction elements other than the friction elements that engage in each speed, on the upstream side of the supply paths L31, L32, L10, L11 and L12. Each switching valve is switched by hydraulic pressure (C1-C3, B1 pressures) regulated by the control means that achieve regulated pressure operating conditions during failures, and selective application of signal pressure (So1, So1B, So1C pressures) output by the control means as operating means.

Abstract: A hydraulic control apparatus of automatic transmission comprising a hydraulic pressure source, hydraulic paths, hydraulic servos for operating friction elements which are coupled with the hydraulic source and the hydraulic paths, a control device arranged on the hydraulic paths for operating engagement release through supply/removal of hydraulic pressure to the hydraulic servos and valves which are arranged on the hydraulic path for cutting off hydraulic pressure from the hydraulic pressure source to the hydraulic servo with hydraulic pressure in the downstream side of the control means as signal pressure.

Abstract: A reduction in the weight and size of a speed-change mechanism is obtained by shortening a high-torque transmission system. The speed-change shock is attenuated by reducing an inertia torque in a muilti-stage vehicular automatic transmission. The vehicular automatic transmission is equipped with a planetary gear set that receives a decelerated rotation and a non-decelerated rotation as inputs and outputs a plurality of speed-change rotations, a reduction planetary gear, an input shaft that passes through an inner side of the planetary gear set, first and third clutches that couple the input shaft to two different speed-change elements of the planetary gear set respectively through the reduction planetary gear in an engageable and disengageable manner, and a second clutch that couples the input shaft to the other speed-change element of the planetary gear set in an engageable and disengageable manner.

Abstract: A control system for an automatic transmission includes a fluid transmission unit connected to an engine; a clutch; a hydraulic servo; output RPM detector for detecting the output RPM of the fluid transmission unit; oil pressure generator for generating the oil pressure fed to the hydraulic servo; and a control unit. The control unit includes a booster for raising the oil pressure according to preset characteristics; change rate detector for detecting the RPM change rate of the output RPM in a preset range at the application of the clutch; and a corrector for correcting the preset characteristics by comparing the detected RPM change rate and a reference RPM change rate. The change rate detector detects the RPM change rate only when the output RPM at the time of starting the engagement of the clutch is higher by a preset value than the maximum of the output RPM in the preset range.

Abstract: An automatic transmission comprises a reduction planetary gear, two clutches transmitting a decelerated rotation transmitted from the reduction planetary gear, and a planetary gear set comprising two elements to which the decelerated rotation is inputted through the two clutches. The reduction planetary gear and the two clutches are arranged in one side of the planetary gear set. The second clutch is closer to the planetary gear set than the clutch. The input side member of the first clutch is connected to an output element of the reduction planetary gear and the input side member of the second clutch. The output side member of the first clutch is extended through the radial inner space of the second clutch and connected to one of the two elements of the planetary gear set. Thus, no member is arranged in the radial outer side of the both clutches, and the both clutches are radially enlarged.

Abstract: An automatic transmission, which establishes automatic shifts in a multiple gear stages by selectively inputting a plurality of input rotations to a planetary gear set, includes first and third clutches connected through a reduction planetary gear to an input shaft and transmits a decelerated rotation to the planetary gear set and a second clutch directly connected to the input shaft and transmits a non-decelerated rotation to the planetary gear set. The reduction planetary gear is arranged on the end of a boss portion of a transmission case wall and the one element is fixed to the end of the boss portion, hydraulic servos of the first and third clutches are arranged on the boss portion, a hydraulic servo of a second clutch is arranged in the other side of the reduction planetary gear from the hydraulic servos, and the hydraulic paths for the hydraulic servos are formed in the boss portion.

Abstract: An automatic transmission establishing multiple gear stages includes a reduction planetary gear, at least two clutches transmitting a decelerated rotation transmitted from the reduction planetary gear, and a planetary gear set inputted the decelerated rotation transmitted through the two clutches. The reduction planetary gear and the two clutches are arranged in one side of the planetary gear set. The reduction planetary gear is arranged between the clutches.

Abstract: An automatic transmission includes a planetary gear set inputted a decelerated rotation and a non-decelerated rotation and outputting a plurality of shift rotations, a reduction planetary gear, an input shaft, first and third clutches which are able to engage/disengage for connecting the input shaft through the reduction planetary gear to two different decelerated rotation input elements of the planetary gear set individually, and a second clutch which is able to engage/disengage for connecting the input shaft to a non-decelerated rotation input element. The first clutch, the third clutch and the reduction planetary gear are arranged together, and the second clutch is arranged in the other side of the planetary gear set.

Abstract: A rotational direction of a rotational element at a high speed gear stage is different from a operational direction of a reaction torque at a low speed gear stage. The rotation by the reaction torque at the low speed gear stage is stopped with a self-energizing operation of a band brake operated by a hydraulic servo. A waiting pressure, which is lower for a predetermined amount than a engagement pressure at the self-energizing operation, and with which a basis of a racing amount occurs after a synchronizing point, is applied to the hydraulic servo until the synchronization is determined. The waiting pressure increases to the engagement pressure after determining the synchronization so that the rotational element is stopped gradually as preventing a long shift time.

Abstract: A lubricant control apparatus for an automatic transmission including a lubricating unit for feeding the lubricating oil to the portions of a speed change mechanism so that the heat to be generated in the speed change mechanism may be absorbed and recovered by the lubricating oil. The lubricant control apparatus includes a detector that detects the acting state of the speed change mechanism; a determiner that determines a necessary lubricating oil flow on the basis of the calorific value in the speed change mechanism, the calorific value being calculated from the detected acting state of the speed change mechanism; and a structure for feeding the lubricating oil to the speed change mechanism on the basis of the determined necessary lubricating oil flow. The lubricant control apparatus feeds an optimum lubricating oil flow according to the acting state of the speed change mechanism.

Abstract: A shift control system of an automatic transmission sets a predetermined gear stage by applying a first frictional engagement element and releasing a second frictional engagement element. A pressure regulating mechanism regulates an oil pressure to be fed to or drained from the first frictional engagement element. A failure detector detects a failure of an apparatus to participate in the regulation and control of the oil pressure which is to be fed to or drained from at least one of the first and second frictional engagement elements. A gear stage inhibitor inhibits the setting of the predetermined gear stage if the failure is detected by the failure detector.

Abstract: In an automatic transmission, a small-capacity second clutch that does not engage for reverse drive is mounted forward of a counter drive gear, and the other engaging elements of relatively larger capacity, that is, first and third clutches and first to third brakes, are disposed rearward of the counter drive gear, so that an axially extending space is formed between the counter drive gear and the second clutch, which space is utilized to accommodate a parking gear. Such an arrangement of engaging elements allows the counter shaft to be placed closer to the input shaft without the parking gear interfering with the second clutch, thereby enabling a more compact automatic transmission. Furthermore, since there is no need to relocate the counter drive gear rearward, the length of the counter shaft can be reduced, thereby enabling still greater compactness.

Abstract: A control system for a vehicular automatic transmission includes a speed change mechanism including an output element that is connected to the drive shaft of a vehicle to transmit power, and a rotary element connected to the output element. A control system for the speed change mechanism is also provided. The control system includes a hydraulic servo actuated brake for retaining the rotary element to check the rotation of the output element in a vehicle roll back direction. The brake includes a band brake that establishes different application forces depending on whether the brake operates by a self-energizing action or a de-energizing action according to the rotational direction of the rotary element.

Abstract: A hydraulic servo device for an automatic transmission is presented with a reduced axial length as a result of the manner in which oil pressure is fed into the cylinder. The hydraulic servo device includes a cylinder, a piston position to slide within the cylinder, a rod connected to the piston, and a cover member for closing the open end of the cylinder. The cover member, in association with the cylinder and the piston, defines an oil chamber in the cylinder. An oil passage for feeding an oil pressure to the oil chamber is formed by an opening in the cover member.

Abstract: When a vehicle is halted with the transmission in a forward drive range, an input clutch is disengaged to enhance the fuel efficiency and, at the same times a hill-hold brake is engaged to prevent the vehicle from rolling backward on a steep up-slope. At that time, the hydraulic pressure P.sub.C-1 of the input clutch C1 is gradually reduced by .DELTA.P.sub.CIR (P.sub.C-1 =P.sub.C-1 -.DELTA.P.sub.CIR) while the hydraulic pressure P.sub.B-1 of the hill-hold brake B1 is increased gradually so as to satisfy an equation P.sub.B-1 =K1+K2 X e where .DELTA.P.sub.cir is a change in hydraulic pressure which is required for gradually disengaging the first clutch C1, K1 is a hill-hold brake pressure at which braking resistance begins, K2 is hill-hold brake pressure producing a fully braked condition, and e is the input/output rotational-speed ratio of a torque converter Subsequently during start of vehicle movement, the hydraulic pressure P.sub.C-1 of the input clutch C1 is gradually increased (P.sub.C-1 =p.sub.C-1 +.

Abstract: A hydraulic servo unit for a vehicular power transmission system having a helical gear, including a clutch for connecting predetermined rotary elements to each other and a hydraulic servo for applying the clutch, the hydraulic servo including a cylinder, a piston fitted in the cylinder, a push member abutting against the piston through a bearing for transmitting the push force of the piston to the clutch, and a return spring for the piston, one of the rotary elements including a reaction member opposed to the push member for transmitting the push force of the piston to a case, and the cylinder is a stationary cylinder formed in the case. Further, the return spring is arranged between the push member and the reaction member and is loaded to apply a load higher than the thrust force of the helical gear, as acting upon the reaction member.

Abstract: An automatic transmission for a vehicle with a reverse gear brake that includes a case. A predetermined rotational element, having gear teeth and an axis, is disposed within the case. The predetermined rotational element only operates as a rotational element when achieving a reverse gear mode. A brake has a gear member. The gear member is attached to the case so that it cannot rotate relative to the case, but is movable along the axis of the predetermined rotational element so that it can be engaged and disengaged with the teeth of the predetermined rotational element. The predetermined rotational element is fixed to the case so that it cannot rotate relative to the case when the gear teeth engage the gear member.