Method and device for controlling automatic transmission

Patent metadata

Field	Value
Publication number	US-10302192-B2
Application number	US-201715595869-A
Country	US
Kind code	B2
Filing date	May 15, 2017
Priority date	May 19, 2016
Publication date	May 28, 2019
Grant date	May 28, 2019

Abstract

A method of controlling an automatic transmission is provided. The automatic transmission includes first and second frictional engageable elements and a hydraulic mechanism. The method includes controlling a first hydraulic pressure control valve of the first element to adjust hydraulic pressure to a given value in a first period in response to the gear shift command and increase the hydraulic pressure until first friction plates engaged in a second period, and a second hydraulic pressure control valve of the second element to pre-charge in response to the gear shift command, maintain the hydraulic pressure at a lower value than a highest target value immediately after the pre-charging, and increase the hydraulic pressure until second friction plates engaged immediately after the maintaining the pressure, a time length of the first period being shorter than a time length between a start of the pre-charging and a start of the increasing the pressure.

First claim

What is claimed is:

1. A method of controlling an automatic transmission including a first frictional engageable element, a second frictional engageable element, and a hydraulic mechanism,
the first frictional engageable element including:
a first piston having a first surface and a second surface opposite from each other in axial directions of the first piston, and movable in the axial directions;
a plurality of first friction plates disposed on the first surface side of the first piston;
a first engaging hydraulic pressure chamber for applying hydraulic pressure to the second surface of the first piston and directing the first piston to an engaging position to push the first friction plates to be engaged with each other to be in an engaged state; and
a first disengaging hydraulic pressure chamber for applying hydraulic pressure to the first surface of the first piston and directing the first piston to a disengaging position to cause the first friction plates to be in a disengaged state, the second surface having a larger area for receiving hydraulic pressure than an area of the first surface for receiving hydraulic pressure,

the second frictional engageable element including:
a second piston having a third surface and a fourth surface opposite from each other in axial directions of the second piston, and movable in the axial directions;
a plurality of second friction plates disposed on the third surface side of the second piston; and
a second engaging hydraulic pressure chamber for applying hydraulic pressure to the fourth surface of the second piston and directing the second piston to an engaging position to push the second friction plates to be engaged with each other,

the hydraulic mechanism including:
a first hydraulic pressure control valve having an output port of hydraulic pressure, and for supplying and discharging hydraulic pressure to and from the first engaging hydraulic pressure chamber and the first disengaging hydraulic pressure chamber;
a first oil path communicating the output port of the first hydraulic pressure control valve with the first engaging hydraulic pressure chamber;
a second oil path communicating the output port with the first disengaging hydraulic pressure chamber;
a second hydraulic pressure control valve having an output port of hydraulic pressure, and for selectively supplying and discharging hydraulic pressure to and from the second engaging hydraulic pressure chamber; and
a third oil path communicating the output port of the second hydraulic pressure control valve with the second engaging hydraulic pressure chamber,

the method comprising:
controlling the first friction plates to change from the disengaged state to the engaged state in response to a gear shift command, the controlling the first friction plates including controlling the first hydraulic pressure control valve to:
adjust the hydraulic pressure to a given value in a first period in response to the gear shift command; and
increase the hydraulic pressure until the first friction plates reach the engaged state in a second period directly following the first period; and

controlling the second friction plates to change from the disengaged state to the engaged state in response to a gear shift command, the controlling the second friction plates including controlling the second hydraulic pressure control valve to:
pre-charge the second engaging hydraulic pressure chamber in response to the gear shift command by supplying hydraulic pressure at a highest target value;
maintain the hydraulic pressure at a lower value than the highest target value immediately after the pre-charging the second engaging hydraulic pressure chamber; and
increase the hydraulic pressure until the second friction plates reach the engaged state immediately after the maintaining the hydraulic pressure, a time length of the first period being shorter than a time length between a start of the pre-charging the second engaging hydraulic pressure chamber and a start of the increasing the hydraulic pressure, wherein

the hydraulic pressure in the first period is maintained at the given value,
the second oil path is provided with a pressure reducing valve for preventing the hydraulic pressure inside the first disengaging hydraulic pressure chamber from exceeding a preset value, and
in adjusting the hydraulic pressure, the pressure reducing valve reduces the hydraulic pressure at the given value to be lower than the preset value.

2. The method of claim 1 , wherein the first piston is formed with a through-hole communicating the first engaging hydraulic pressure chamber with the first disengaging hydraulic pressure chamber.

3. The method of claim 2 , wherein a restricting mechanism for restricting an oil flow between the first engaging hydraulic pressure chamber and the first disengaging hydraulic pressure chamber is disposed in the through-hole.

4. The method of claim 3 , wherein a volume of the second engaging hydraulic pressure chamber in the engaged state is smaller than that of the first engaging hydraulic pressure chamber in the engaged state.

5. The method of claim 1 , wherein a first period change of the hydraulic pressure in adjusting the hydraulic pressure to the given value in the first period is changed more gradually than a second period change of hydraulic pressure in the second period where the hydraulic pressure is increased.

6. The method of claim 5 , wherein
the second oil path is provided with a pressure reducing valve for preventing the hydraulic pressure inside the first disengaging hydraulic pressure chamber from exceeding a preset value, and
in adjusting the hydraulic pressure, the pressure reducing valve reduces the hydraulic pressure at the given value to be lower than the preset value.

7. The method of claim 6 , wherein the first piston is formed with a through-hole communicating the first engaging hydraulic pressure chamber with the first disengaging hydraulic pressure chamber.

8. The method of claim 7 , wherein a restricting mechanism for restricting an oil flow between the first engaging hydraulic pressure chamber and the first disengaging hydraulic pressure chamber is disposed in the through-hole.

9. The method of claim 8 , wherein a volume of the second engaging hydraulic pressure chamber in the engaged state is smaller than that of the first engaging hydraulic pressure chamber in the engaged state.

10. A method of controlling an automatic transmission including a first frictional engageable element, a second frictional engageable element, and a hydraulic mechanism,
the first frictional engageable element including:
a first piston having a first surface and a second surface opposite from each other in axial directions of the first piston, and movable in the axial directions;
a plurality of first friction plates disposed on the first surface side of the first piston;
a first engaging hydraulic pressure chamber for applying hydraulic pressure to the second surface of the first piston and directing the first piston to an engaging position to push the first friction plates to be engaged with each other to be in an engaged state; and
a first disengaging hydraulic pressure chamber for applying hydraulic pressure to the first surface of the first piston and directing the first piston to a disengaging position to cause the first friction plates to be in a disengaged state, the second surface having a larger area for receiving hydraulic pressure than an area of the first surface for receiving hydraulic pressure,

the second frictional engageable element including:
a second piston having a third surface and a fourth surface opposite from each other in axial directions of the second piston, and movable i

Assignees

• Mazda Motor

Inventors

• Fukuda Yutaro
• Sasahara Manabu
• Saito Tadashi
• Kubo Tomohiro

Classifications

• F16D25/06

  in which the fluid actuates a piston incorporated in, {i.e. rotating with} the clutch (F16D25/02 takes precedence) · CPC title

• F16H3/66

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

• F16H61/06 Primary

  by controlling rate of change of fluid pressure · CPC title

• F16H2061/062

  for controlling filling of clutches or brake servos, e.g. fill time, fill level or pressure during filling · CPC title

• F16H2063/303

  the friction member is actuated and released by applying pressure to different fluid chambers · CPC title