Control device for an automatic transmission

• US 6,740,006 B2
• Filed: 09/17/2002
• Issued: 05/25/2004
• Est. Priority Date: 08/20/1999
• Status: Expired due to Fees

• Current Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: Tabata, Atsushi
• Primary Examiner(s): HO, HA DINH
• Application Number:
  US10/244,373
• Publication Number:
  US 20030013571A1
• Time in Patent Office: 616 Days
• Field of Search: 475/254, 477/97, 477/901, 477/903, 477/125, 477/118, 701/52, 701/65
• US Class Current: 477/118
• CPC Class Codes: F16H 2059/0239 Up- and down-shift or range or mode selection by repeated movement mechanical step by step selection devices F16H63/14
• CPC Class Codes: F16H 59/0204 for automatic transmissions with means for range selection and manual shifting, e.g. range selector with tiptronic
• CPC Class Codes: F16H 61/0213 characterised by the method for generating shift signals
• CPC Class Codes: F16H 61/16 Inhibiting or initiating shift during unfavourable conditions, e.g. preventing forward reverse shift at high vehicle speed, preventing engine over speed unintentional control input F16H61/18
• CPC Class Codes: Y10S 477/901 Control signal is slope

Abstract

A control device for an automatic transmission which prevents an automatic transmission from executing a “busy-shift” caused by a lower gear ratio of the highest gear, and which reduces revolutions of a driving power source at high speed. The control device includes an automatic shift mode, an independent manual shift mode, and a highest gear control. The automatic shift mode automatically determines a gear ratio of the automatic transmission on the basis of a driving condition of a vehicle having the automatic transmission. The manual shift mode determines a gear ratio of the automatic transmission by a driver'"'"'s intention. The highest gear control controls the automatic transmission, so that the smallest gear ratio set by the manual shift mode is smaller than the smallest gear ratio set by the automatic shift mode. If the gear ratio of the highest gear of the automatic shift mode is not so small, a shift caused by a change of a driving condition does not easily occur. The busy-shift can be avoided in the automatic transmission.

Claims

1. A control device for an automatic transmission comprising:

a plurality of gears including a highest gear;

means for determining a high vehicle speed condition; and

a highest gear prohibition means for prohibiting the smallest gear ratio of the gears of the automatic transmission when a running resistance of the vehicle is equal to or over a predetermined value and the high vehicle speed condition is determined to be present.