Mazda Motor Corporation

Koshiro Saji

Shinya Kamada

Shotaro Nagai

Tatsuhiko Iwasaki

Tadashi Saito

Tomotaka Ishizaka

Manabu Sasahara

Masaru Nakagishi

Yuki Tsuchitori

Motomi Kobayashi

Tatsutoshi Mizobe

Kazuhiko Ueda

Yasunari Nakayama

Tatsuya Uesugi

Norio Iwashita

Yutaro Fukuda

Tomohiro Kubo

Yasuo Shigenaka

Masako Shinohara

Kaori Sako

Shinsuke Yoshiura

Masahiro Kaji

An automatic transmission includes a piston movable in an axial direction, a plurality of friction plates disposed on a side of a first surface of the piston, a fastening hydraulic chamber applying a hydraulic pressure to a second surface of the piston to move the piston to a fastening position where the friction plates are pressed to be fastened to each other, a release hydraulic chamber applying a hydraulic pressure to the first surface of the piston to move the piston to a release position where the friction plates are released, and a hydraulic pressure control valve that supplies and discharges the hydraulic pressure to and from each of the fastening hydraulic chamber and the release hydraulic chamber. An area of the second surface of the piston for receiving the hydraulic pressure is set to be larger than an area of the first surface for receiving the hydraulic pressure.

Automatic transmission

Provided is a frictional engagement element including: a plurality of friction plates; a piston movable between a releasing position and an engaging position; and a first urging mechanism and a second urging mechanism configured to urge the piston in an engaging direction from the releasing position toward the engaging position. Urging forces of both of the first urging mechanism and the second urging mechanism act on the piston from the releasing position to a first position in the engaging direction. The urging force of the first urging mechanism acts on the piston from the first position to a second position closer to the engaging position than the first position. The first position is a predetermined position where the piston does not abut against the friction plates, and the second position is a position where the piston abuts against the friction plates and the clearances are reduced.

Frictional engagement element and automatic transmission

A transmission is provided including a transmission case accommodating a transmission mechanism, a hydraulic controller having a valve body and a valve for controlling the transmission mechanism, the valve body formed with a valve insertion hole into which the valve is inserted, and an oil path communicating with the valve insertion hole, and an oil storage for storing oil. At least one of the valve body and the oil storage is integrally formed with the transmission case.

Automatic transmission and method of manufacturing the same

Provided is an automatic transmission including: an input section to which power generated by a drive source is input; an output section configured to output a drive force; and a gear shifting mechanism configured to change a gear ratio. The power is input to the input section without intervention of a hydraulic power transmission device. The gear shifting mechanism includes a predetermined frictional engagement element for achieving a starting gear ratio of a vehicle. The frictional engagement element includes: a plurality of friction plates arranged with clearances therebetween; a piston movable between a releasing position where the friction plates are brought into a released state, and an engaging position where the friction plates are brought into an engaged state by pressing the friction plates; and an urging mechanism configured to urge the piston so that the piston abuts against the friction plates and the clearances are reduced.

A hydraulic control unit for an automatic transmission has a mechanically-operated oil pump (), an electrically-operated oil pump () actuated while an engine () is automatically shut down, and a hydraulic pressure circuit () which controls supply of hydraulic pressure to a frictional engagement element () to be engaged, in the automatic transmission, at a vehicle's start. In the hydraulic pressure circuit, discharge oil from the electrically-operated oil pump is drained from a predetermined drain portion () when a selector valve () is in the first state (in which the mechanically-operated oil pump is a source of the supply of the hydraulic pressure to the frictional engagement element), whereas less discharge oil is drained from the drain portion, compared to the first state, when the selector valve () is in the second state (in which the electrically-operated oil pump is the source of the supply of the hydraulic pressure).

Hydraulic control unit for automatic transmission

An automatic transmission includes a first frictional engagement element (a low clutch), a second frictional engagement element (an L/R brake), two hydraulic chambers (a gap adjustment chamberand a pressure chamber) provided in the second frictional engagement element, a first hydraulic pressure generator(an electric pump) generating a hydraulic pressure during an automatic stop of the engine, and a control unit (a control unit) controlling the hydraulic pressure in the first and second frictional engagement elements. The control unit supplies the hydraulic pressure generated by the first hydraulic pressure generator to the first frictional engagement element and one of the two hydraulic chambers of the second frictional engagement element when the automatic transmission is in the non-traveling range and the engine has been automatically stopped.

A hydraulic control circuit includes: a shift valve configured to be switched between a state of supplying oil pressure to a clearance adjusting chamber of an LR brake and a state of discharging the oil pressure from the clearance adjusting chamber of the LR brake; and a linear SV configured to control the oil pressure supplied to a pressing chamber of the LR brake. The hydraulic control circuit further includes a source pressure oil passage through which oil pressure equal to the oil pressure supplied from the shift valve to the clearance adjusting chamber is supplied to a source pressure port a of the linear SV. By discharging the oil pressure in the clearance adjusting chamber at the time of opening malfunction of the linear SV, the oil pressure in the pressing chamber is also discharged through a drain port of the shift valve.

Hydraulic control device of automatic transmission

A hydraulic control device of an automatic transmission configured such that: a first gear stage is formed by engagement of an LR brake and a low clutch; a third gear stage by engagement of the low clutch and an R35 brake; and a reverse gear stage by engagement of the LR brake and the R35 brake. The hydraulic control device includes a cut valve configured to be switched between a first state where a source pressure port of a third linear solenoid valve (SV) configured to control an oil pressure supplied to the R35 brake is connected to an oil pressure source and a second state where the pressure is discharged from the port. The cut valve becomes the second state when the third gear stage is shifted to the first gear stage, and the oil pressure supplied to the low clutch is less than a predetermined oil pressure.

A control method for an automatic transmission in which a starting gear shift stage is attained by fastening a predetermined brake element and a predetermined clutch element includes a step of supplying, when a command, which is for fastening the predetermined brake element and the predetermined clutch element that is to be fastened to input output rotation on an engine side to a transmission mechanism, and which is also for attaining the starting gear shift stage is detected, hydraulic pressure to the clutch element and then fastening the clutch element, and a step of supplying, after the step, the hydraulic pressure to the brake element to start the fastening of the brake element and controlling rotation, which is input to the transmission mechanism, to a target number of rotations. It is possible to satisfactorily attain the starting gear shift stage without a shock while dispensing with a one-way clutch.

Automatic transmission control method, control device, and automatic transmission system

A hydraulic control device of an automatic transmission is provided, which includes a hydraulic control circuit with a pressure reducing valve including a first friction element for achieving a first gear position and a second friction element for achieving a second gear position that produces a lower speed than the first gear position. The hydraulic control circuit further includes a switch valve formed with an input port which is inputted with the line pressure in a forward gear position range, and which is switched between a first state where the input port communicates with a first oil path communicating with the first friction element in a failure state of power distribution to the plurality of hydraulic control valves, and a second state where the input port communicates with the second friction element in the same power distribution failure state. The switch valve includes various control ports to control its function.

A vehicle idle stop system is disclosed. The idle stop system comprises an engine, an automatic transmission, a first oil pump driven by said engine and generating hydraulic pressure which is supplied to a friction element of said automatic transmission, a second oil pump capable of operating and generating hydraulic pressure which is supplied to a friction element of said automatic transmission during an engine stop, and a controller. The controller is configured to control the engine to stop when a predetermined engine stop condition is satisfied, and to control the second oil pump to supply hydraulic pressure to a predetermined friction element coupled to a forward starting gear of the automatic transmission, the hydraulic pressure supplied to couple the predetermined friction element when the engine is automatically stopped and when a gear range of the automatic transmission is in a neutral range.

Idle stop control device for vehicle

An oil-pressure output device (electric pump unit) is arranged on an outer wall face of an automatic transmission which is positioned on an opposite side to an engine (left side of a vehicle). An arrangement position of the oil-pressure output device is out of a movable range of one of the steered driving wheels which is located on the opposite side to the engine (left front wheel). Accordingly, a simpler layout change between a case of attaching the oil-pressure output device to the automatic transmission and another case of not attaching the one can be provided, so that commonality of components or layout of the automatic transmission and its surrounding devices and structures can be provided.

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Hiroshima, Japan

Koshiro Saji