AUTOMATIC TRANSMISSION CONTROL DEVICE

• US 20180259065A1
• Filed: 10/21/2016
• Published: 09/13/2018
• Est. Priority Date: 10/28/2015
• Status: Active Grant

• Current Assignee: Jatco Limited (Nissan Motor Co., Ltd.)
• Original Assignee: Jatco Limited (Nissan Motor Co., Ltd.)
• Inventors: FUJII, Ryosuke, SHIOKAWA, Hiroaki
• Granted Patent: US 10,641,386 B2
• Time in Patent Office: Days
• CPC Class Codes: F16H 2061/0411 by control of shaft brakes
• CPC Class Codes: F16H 2061/0488 during range shift from neutral (N) to drive (D)
• CPC Class Codes: F16H 2200/0056 the gear ratios comprising seven forward speeds
• CPC Class Codes: F16H 2200/2012 with four sets of orbital gears
• CPC Class Codes: F16H 2200/2051 with eight engaging means
• CPC Class Codes: F16H 2200/2071 using three freewheel mechanism
• CPC Class Codes: F16H 2200/2087 three freewheel mechanisms
• CPC Class Codes: F16H 2312/022 Preparing to drive off
• CPC Class Codes: F16H 3/66 composed of a number of gear trains without drive passing from one train to another
• CPC Class Codes: F16H 59/42 Input shaft speed
• CPC Class Codes: F16H 59/70 dependent on the ratio established
• CPC Class Codes: F16H 59/72 dependent on oil characteristics, e.g. temperature, viscosity
• CPC Class Codes: F16H 59/78 Temperature
• CPC Class Codes: F16H 61/0437 by using electrical signals F16H61/0403 and F16H61/061 take precedence
• CPC Class Codes: F16H 61/686 with orbital gears

Abstract

In an automatic transmission control device of the invention configured to start an increase in engagement pressure of a start-up engagement element, when a determination threshold value for determining that a turbine rotational speed has reduced is reached or exceeded, the determination threshold value when a selection operation from a non-traveling range to a traveling range is made before a prescribed period of time from starting of an engine has elapsed, is increased and set greater than the determination threshold value when the selection operation is made after the prescribed period of time has elapsed. Accordingly, a reduction in the turbine rotational speed can be accurately determined, and thus it is possible to suppress torque fluctuations, occurring owing to engagement of a second brake, which is the start-up engagement element.

Claims

1. An automatic transmission control device configured to start an increase in engagement pressure of a start-up engagement element when a determination threshold value for determining that an input shaft rotational speed of an automatic transmission has been determined to have reduced is reached or exceeded, characterized in that,

the determination threshold value when a selection operation from a non-traveling range to a traveling range is made before a prescribed period of time from starting of an engine has elapsed, is increased and set greater than the determination threshold value when the selection operation is made after the prescribed period of time has elapsed.

2. The automatic transmission control device as recited in claim 1, wherein:

the determination threshold value when an oil temperature during a starting period of the engine is less than a prescribed oil temperature is increased and set greater than the determination threshold value when the oil temperature is greater than or equal to the prescribed oil temperature.

3. The automatic transmission control device as recited in claim 1, wherein:

the determination threshold value is a prescribed count value for determining a count value of a sequence of events that the input shaft rotational speed has been determined to have reduced.

4. The automatic transmission control device as recited in claim 1, further comprising:

a planetary gear train having a first planetary gear, a second planetary gear, a third planetary gear, and a fourth planetary gear arranged from a side of an input shaft to a side of an output shaft, in that order;

an input rotating member configured to extend toward an outer diameter side from the input shaft and connected to a ring gear of the second planetary gear between the second planetary gear and the third planetary gear;

a first connecting member connected at one end to a carrier of the second planetary gear between the first planetary gear and the second planetary gear, and at the other end to a ring gear of the fourth planetary gear, and configured to cover an outer diameter side of the second planetary gear and the third planetary gear;

a planetary gearset constituted by connecting respective two rotating elements of the first planetary gear and the second planetary gear;

a plurality of engagement elements that determine a gear ratio of the planetary gear train;

a first rotation sensor that detects a rotational speed of the first connecting member; and

a second rotation sensor that detects a rotational speed of a rotating element of the planetary gearset, the rotating element having the rotational speed different from the first connecting member,

wherein the input shaft rotational speed is calculated based on the rotational speed detected by the first rotation sensor and the rotational speed detected by the second rotation sensor.