US4572029A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Speed change control method and device of automatic transmission for vehicle
Assignee: Toyota Motor Corp
•
Filing: 1982-01-08
•
Granted: 1986-02-25
•
Expires: 2002-01-08
Abstract
Abstract A speed change method and apparatus for the transmission of a vehicle provides for a speed change stage to produce a reduction gear ratio lower than a predetermined value when the engine temperature is low and vehicle speed is high, otherwise the speed change stage is prohibited from operating.
Inventors
- 👤 Yukio Kinugasa
- 👤 Takehisa Yaegashi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 13:47
CPC Classifications
F; F16; F16H; F16H61/00; F16H61/02; F16H61/0202; F16H61/0204; F16H61/0213; B; B60; B60W; B60W2510/00; B60W2510/06; B60W2510/0676; F16H2061/0232; F16H59/00; F16H59/74; F16H59/78; Y; Y10; Y10S; Y10S477/00; Y10S477/902
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
173 words
A speed change control device of an automatic transmission for a vehicle, said control device comprising: a first voltage producing means for producing voltage related with engine temperature; a second voltage producing means for producing voltage related with vehicle speed; a first comparator for comparing the output voltage of the first voltage producing means with a first predetermined value; a second comparator for comparing the output voltage of the second voltage producing means with a second predetermined value; an oil pressure supply controlling means for controlling oil pressure supply to a hydraulic servo for a friction engaging device upon receiving operating signals when a speed change stage producing a reduction gear ratio lower than a predetermined value is to be performed; and a blocking means for blocking input of the operating signals to the oil pressure supply controlling means only when the engine temperature is lower than the first predetermined value and the vehicle speed is lower than the second predetermined value in response to the outputs of the first and second comparators.
Claim 2
Dependent Claim
173 words
A speed change control device of an automatic transmission for a vehicle, said control device comprising: a first voltage producing means for producing voltage related with engine temperature; a second voltage producing means for producing voltage related with vehicle speed; a first comparator for comparing the output voltage of the first voltage producing means with a first predetermined value; a second comparator for comparing the output voltage of the second voltage producing means with a second predetermined value; an oil pressure supply controlling means for controlling oil pressure supply to a hydraulic servo for a friction engaging device upon receiving operating signals when a speed change stage producing a reduction gear ratio lower than a predetermined value is to be performed; and a blocking means for blocking input of the operating signals to the oil pressure supply controlling means only when the engine temperature is lower than the first predetermined value and the vehicle speed is lower than the second predetermined value in response to the outputs of the first and second comparators.
Claim 3
Dependent Claim
30 words
A speed change control device as defined in claim 1, wherein the first voltage producing means produces voltage related to the temperature of cooling water corresponding to the engine temperature.
Claim 4
Dependent Claim
30 words
A speed change control device as defined in claim 2, wherein the automatic transmission is of a four forward speed type and said speed change stage comprises the fourth speed.
Claim 5
Dependent Claim
21 words
A speed change control device as defined in claim 3, wherein said speed change stage comprises the third and fourth speeds.
Claim 6
Dependent Claim
124 words
A speed change control method of an automatic transmission for a vehicle, comprising the following steps: producing a first voltage related with engine temperature; producing a second voltage related with vehicle speed; comparing the first voltage with a predetermined value; comparing the second voltage with a second predetermined value; controlling an oil pressure supply to a hydraulic servo for a friction engaging device upon receiving operating signals when a speed change stage producing a reduction gear ratio lower than a predetermined value is to be performed; and blocking input of the operating signals only when the engine temperature is lower than the first predetermined value and the vehicle speed is lower than the second predetermined value in response to the first and second comparisons.
Claim 7
Dependent Claim
124 words
A speed change control method of an automatic transmission for a vehicle, comprising the following steps: producing a first voltage related with engine temperature; producing a second voltage related with vehicle speed; comparing the first voltage with a predetermined value; comparing the second voltage with a second predetermined value; controlling an oil pressure supply to a hydraulic servo for a friction engaging device upon receiving operating signals when a speed change stage producing a reduction gear ratio lower than a predetermined value is to be performed; and blocking input of the operating signals only when the engine temperature is lower than the first predetermined value and the vehicle speed is lower than the second predetermined value in response to the first and second comparisons.
Claim 8
Dependent Claim
30 words
A speed change control method as defined in claim 5, wherein the first voltage producing step produces voltage related to the temperature of cooling water corresponding to the engine temperature.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-02-24 | 1989-08-26 | 1990-02-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-02-24 | 1993-08-26 | 1994-02-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-02-24 | 1997-08-26 | 1998-02-25 | $7700.00 | Window Closed / Lapsed |