US4785689A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Failsafe system in automatic transmission
Assignee: Toyota Motor Corp
•
Filing: 1986-12-23
•
Granted: 1988-11-22
•
Expires: 2006-12-23
Abstract
Abstract A failsafe system in an automatic transmission includes: a device for detecting rotary speed of an output shaft of the automatic transmission; a device for detecting either rotary speed of a rotary member other than the output shaft of the automatic transmission or engine rotary speed. When a correlation between the output shaft rotary speed and either the rotary speed of the rotary member or the engine rotary speed is abnormal, control oil pressure in a hydraulic control device of the automatic transmission is increased, whereby slippage in frictionally engaging devices in the hydraulic control device of the automatic transmission during non-shift are effectively eliminated.
Inventors
- 👤 Kunihiro Iwatsuki
- 👤 Yoshio Shindo
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 18:43
CPC Classifications
F; F16; F16H; F16H61/00; F16H61/0021; F16H61/12; F16H59/00; F16H59/36; F16H59/46; F16H2059/465; F16H61/04; F16H2061/0462; F16H59/38; F16H59/40; F16H61/68; F16H61/684; F16H61/686; Y; Y10; Y10S; Y10S477/00; Y10S477/906
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
154 words
A failsafe system in an automatic transmission for a vehicle, comprising: means for detecting an output shaft rotary speed of said automatic transmission; means for detecting engine rotary speed; means for detecting engine load; means for detecting whether a lockup clutch of said automatic transmission is engaged; means for detecting whether a prescribed period of time has elapsed from either a shift judgment or a shift command of said automatic transmission; means for determining a correlation between said output shaft rotary speed and said engine rotary speed when said engine load is higher than a predetermined value, said lockup clutch is engaged, and said prescribed period of time has elapsed from either of said shift judgment or shift command of said automatic transmission; means for judging whether said correlation is abnormal; and means for increasing oil pressure in a hydraulic control device of said automatic transmission when said correlation is judged to be abnormal.
Claim 2
Dependent Claim
154 words
A failsafe system in an automatic transmission for a vehicle, comprising: means for detecting an output shaft rotary speed of said automatic transmission; means for detecting engine rotary speed; means for detecting engine load; means for detecting whether a lockup clutch of said automatic transmission is engaged; means for detecting whether a prescribed period of time has elapsed from either a shift judgment or a shift command of said automatic transmission; means for determining a correlation between said output shaft rotary speed and said engine rotary speed when said engine load is higher than a predetermined value, said lockup clutch is engaged, and said prescribed period of time has elapsed from either of said shift judgment or shift command of said automatic transmission; means for judging whether said correlation is abnormal; and means for increasing oil pressure in a hydraulic control device of said automatic transmission when said correlation is judged to be abnormal.
Claim 3
Dependent Claim
21 words
The failsafe system as set forth in claim 1, wherein said oil pressure in the hydraulic control device is line pressure.
Claim 4
Dependent Claim
34 words
The failsafe system as set forth in claim 1, further comprising: an electromagnetic proportion valve; wherein said oil pressure in the hydraulic control device is increased by the control of said electromagnetic proportion valve.
Claim 5
Dependent Claim
33 words
The failsafe system as set forth in claim 1, further comprising: a duty valve; wherein said oil pressure in the hydraulic control device is increased by the duty control of said duty valve.
Claim 6
Dependent Claim
43 words
The failsafe system as set forth in claim 1, further comprising: means for judging whether said correlation is shifted more than a predetermined value; wherein said judging means judges said correlation is abnormal when said correlation is shifted more than said predetermined value.
Claim 7
Dependent Claim
55 words
The failsafe system as set forth in claim 1, further comprising: means for judging whether said correlation is shifted more than a predetermined value for a predetermined period of time; wherein said judging means judges said correlation is abnormal when said correlation is shifted more than said predetermined value for a predetermined period of time.
Claim 8
Dependent Claim
31 words
The failsafe system as set forth in claim 1, further comprising: a warning device; wherein, when said correlation is judged to be abnormal, a warning is issued from said warning device.
Claim 9
Dependent Claim
149 words
A failsafe system in an automatic transmission for a vehicle, comprising: means for detecting rotary speed of an output shaft of said automatic transmission; means for detecting rotary speed of a turbine shaft of said automatic transmission; means for detecting engine load; means for detecting whether a prescribed period of time has elapsed from either a shift judgment or a shift command of said automatic transmission; means for determining a correlation between the rotary speed of the output shaft and the rotary speed of the turbine shaft when said engine load is higher than a predetermined value, and said prescribed period of time has elapsed from either of said shift judgment or shift command of said automatic transmission; means for judging whether said correlation is abnormal; and means for increasing oil pressure in a hydraulic control device of said automatic transmission when said correlation is judged to be abnormal.
Claim 10
Dependent Claim
149 words
A failsafe system in an automatic transmission for a vehicle, comprising: means for detecting rotary speed of an output shaft of said automatic transmission; means for detecting rotary speed of a turbine shaft of said automatic transmission; means for detecting engine load; means for detecting whether a prescribed period of time has elapsed from either a shift judgment or a shift command of said automatic transmission; means for determining a correlation between the rotary speed of the output shaft and the rotary speed of the turbine shaft when said engine load is higher than a predetermined value, and said prescribed period of time has elapsed from either of said shift judgment or shift command of said automatic transmission; means for judging whether said correlation is abnormal; and means for increasing oil pressure in a hydraulic control device of said automatic transmission when said correlation is judged to be abnormal.
References Cited (Backward Citations)
DE2125178A1
Cited
US3937108A
Cited
DD136415A1
Cited
JPS5536611A
Cited
US4393732A
Cited
JPS5649447A
Cited
JPS5649450A
Cited
US4414863A
Cited
US4331046A
Cited
GB2084673A
Cited
JPS57173647A
Cited
US4506564A
Cited
JPS599356A
Cited
JPS6011753A
Cited
JPS6092931A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-11-22 | 1992-05-23 | 1992-11-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-11-22 | 1996-05-23 | 1996-11-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-11-22 | 2000-05-23 | 2000-11-22 | $7700.00 | Window Closed / Lapsed |