Aisin Aw Co., Ltd.

Akitoshi Kato

Kazumasa Tsukamoto

Masahiro Hayabuchi

Masaaki Nishida

Satoru Kasuya

Hiroshi Kato

Nobutada Sugiura

Takao Taniguchi

Tatsuya Iida

Shuzo Moroto

Tokuyuki Takahashi

Masafumi Kinoshita

Shoichi Miyagawa

Katsuyuki Tanahashi

Mitsutaka Ito

Takuya Ogino

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 helical 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.

Automatic transmission

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.

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.

Automatic transmission for vehicle

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.

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.

Hydraulic servo unit for vehicular power transmission system

A hydraulic servo-mechanism for an automatic transmission, including a hydraulic servo for applying a band brake to engage a band to a drum. The hydraulic servo includes a rod which is selectively positionable to an apply position for applying the band brake, a standby position in which the rod is retracted by a predetermined extent in a release direction from the apply position, and a retracted position in which the rod is further retracted in the release direction from the standby position to release the band brake.

Hydraulic servo-mechanism for an automatic transmission

A band brake drum supporting device for an automatic transmission having a band drum to be retained in a case by fastening a band brake which is joined to a rotary element of the automatic transmission and arranged in the case. The drum includes a band engaging portion and a cylindrical drum supporting portion extending radially inward from the band engaging portion while being offset axially with respect to the band engaging portion. The outer circumference of the drum supporting portion is supported through two axially juxtaposed bearings on a stationary support portion which extends radially outward of the drum supporting portion from the case. The stationary support portion includes a cylindrical boss portion disposed coaxially with the drum supporting portion and engaging at its inner circumference with the two bearings and a planar flange portion extending radially outward from the end portion of the boss portion which is located closer to the band brake.

Band brake drum supporting device for automatic transmission

A 5-speed automatic transmission for a vehicle having a highly efficient top gear, a compact construction and a wide overall range of gear ratios. The automatic transmission has a speed changer which provides five gear stages, namely two speeds on the speed decreasing side and two speeds on the speed increasing side with a direct-coupled gear therebetween. The speed changer includes a ring gear connected to an output shaft, a first carrier, a first sun gear, a second carrier connected to the first carrier, a stepped pinion gear supported by these two carriers, and a sun gear meshing with the pinion gear. The first carrier is connected to an input shaft by a clutch and the first sun gear is connected to the input shaft by a clutch. The first sun gear may be stopped by a first brake, a second brake stops the second sun gear and a third brake is provided to stop a third sun gear. Top gear is achieved by meshing of the pinion gear with the second sun gear and the ring gear. Top gear is thus achieved with the equivalent of only one planetary gear set of intermeshing elements and without loss of efficiency. Also, the arrangement of the three planetary gear sets of the transmission is such that one planetary gear set can be easily removed to make a 4-speed transmission derived from the 5-speed transmission of the invention.

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Anjo, Japan

Akitoshi Kato