Automatic transmission

Patent metadata

Field	Value
Publication number	US-9927027-B2
Application number	US-201715466944-A
Country	US
Kind code	B2
Filing date	Mar 23, 2017
Priority date	Mar 24, 2016
Publication date	Mar 27, 2018
Grant date	Mar 27, 2018

Abstract

The automatic transmission which includes a third brake element formed by a support member including a first cylindrical portion having a first sliding surface at an outer peripheral surface thereof, a second cylindrical portion having a second sliding surface at an inner peripheral surface thereof and a third cylindrical portion having a third sliding surface at an inner peripheral surface thereof, an inner side piston, inner edge portion of which is in contact with the first sliding surface and an outer edge portion of which is in contact with the second sliding surface and an outer side piston which includes a first piston cylindrical portion, outer edge of which is in contact with the second sliding surface over an entire periphery thereof and a second piston cylindrical portion, outer edge portion of which is in contact with the third sliding surface over an entire periphery thereof.

First claim

What we claim is:

1. An automatic transmission comprising:
a housing;
a plurality of planetary gear mechanisms accommodated in the housing and arranged coaxially with a rotation axis line;
a double chamber brake having a first hydraulic chamber and a second hydraulic chamber for connecting or disconnecting one element of one of the plurality of planetary gear mechanisms to or from the housing, wherein
the double chamber brake includes;
a support member which is formed with a first cylindrical portion formed cylindrically and arranged coaxially with the rotation axis line, the first cylindrical portion having a first sliding surface on an outer peripheral surface thereof, a second cylindrical portion cylindrically formed and arranged coaxially with the first cylindrical portion at an outer peripheral surface side of the first cylindrical portion, the second cylindrical portion having a second sliding surface on an inner peripheral surface thereof, a connecting portion connecting the first cylindrical portion and the second cylindrical portion at each one end in a rotation axis line direction and a third cylindrical portion cylindrically formed and an inner diameter thereof being larger than an inner diameter of the second cylindrical portion and connected to the second cylindrical portion at another end thereof in the rotation axis line direction, the third cylindrical portion having a third sliding surface on an inner peripheral surface thereof;
an inner side piston provided with the first hydraulic pressure chamber between the connecting portion of the support member and the inner side piston, an annular shape inner edge portion of the inner side piston being in contact with an entire periphery of the first sliding surface of the first cylindrical portion of the support member and an annular shape outer edge portion being in contact with an entire periphery of the second sliding surface of the second cylindrical portion of the support member;
an outer side piston provided adjacent to the inner side piston, the outer side piston having a first piston cylindrical portion formed cylindrically and arranged coaxially with the rotation axis line, an outer edge portion of the first piston cylindrical portion being in contact with an entire periphery of the second sliding surface, a second piston cylindrical portion cylindrically formed and arranged coaxially at an outer peripheral surface side of the first piston cylindrical portion with the first piston cylindrical portion, an outer edge portion of the second piston cylindrical portion being in contact with an entire periphery of the third sliding surface and a piston connecting portion formed with the second hydraulic pressure chamber between the second cylindrical portion and the piston connecting portion and connecting the first piston cylindrical portion and the second piston cylindrical portion;
a plurality of outer plates, each having an annular plate shape and arranged along in the rotation axis line direction, the plurality of outer plates being prevented from moving in a peripheral direction relative to the housing and being allowed to be movable along the rotation axis line, the plurality of outer plates being pushed by the outer side piston; and
a plurality of inner plates, each having an annular plate shape and each being provided between the outer plates, the plurality of the inner plates being prevented from moving in a peripheral direction relative to the one element of the one of the plurality of planetary gear mechanisms and being allowed to be movable along the rotation axis line.

2. The automatic transmission according to claim 1 , wherein,
the outer side piston includes a contacting portion formed opposing to the inner side piston and extending towards an inner peripheral side of the first piston cylindrical portion the contacting portion being in contact with the inner side piston.

3. The automatic transmission according to claim 2 , wherein,
the inner side piston moves in a first direction where the inner side piston is separated from the connecting portion due to an expansion of the first hydraulic pressure chamber when a hydraulic pressure is supplied to the first hydraulic pressure chamber and the outer side piston moves in the first direction by a movement of the contacting portion accompanied by the movement of the inner side piston and wherein
only the outer side piston moves in the first direction due to an expansion of the second hydraulic pressure chamber when a hydraulic pressure is supplied to the second hydraulic pressure chamber.

4. The automatic transmission according to claim 2 , wherein,
a communication hole is provided at the contacting portion of the outer side piston for fluidically connecting a first space formed between the contacting portion and the inner side piston and a second space formed at the opposite side to the first space across the contacting portion.

5. The automatic transmission according to claim 4 , wherein,
the communication hole controls fluid flow between the first space and the second space in response to an expansion or contraction of the first space caused by a movement of the outer side piston relative to the inner side piston.

6. The automatic transmission according to claim 1 , wherein,
the contacting portion is formed in a stepped shape in cross section and the inner side piston is formed in a corresponding stepped shape in cross section to be in contact with the contacting portion in the stepped shape in cross section.

7. The automatic transmission according to claim 1 , further comprising:
a third space recessively formed at an opposite side to the inner side piston across the contacting portion;
a biasing member provided in the third space and contacting the contacting portion at one end thereof for biasing the contacting portion in an opposite direction to the first direction; and
a biasing member supporting member fixed to the support member and supporting the other end of the biasing member.

Assignees

• Aisin Seiki

Inventors

• Niimi Hideaki
• Nakamura Hideki
• Suwa Keita
• Todo Minoru
• Fukaya Tsuyoshi
• Nakajima Takuya

Classifications

• F16D55/24

  with a plurality of axially-movable discs, lamellae, or pads, pressed from one side towards an axially-located member · CPC title

• F16H2200/2046

  with six engaging means · CPC title

• B60T1/062

  acting on transmission parts · CPC title

• F16H63/3026 Primary

  comprising friction clutches or brakes (band brake actuating mechanisms F16H63/3003) · CPC title

• F16H3/66

  composed of a number of gear trains without drive passing from one train to another · CPC title