US3903759A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Control system for automatic transmissions
Assignee: Toyota Motor Corp
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Filing: 1973-07-25
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Granted: 1975-09-09
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Expires: 1993-07-25
Abstract
Abstract The disclosed control system actuates predetermined combinations of hydraulic valves which establish the desired gear ratios in a four-forward one-reverse speed transmission of a vehicle. In the control system, a selector selects the desired operating condition, such as drive, reverse, etc., of the transmission. A first sensor arrangement senses the speed of the vehicle and produces corresponding speed signals. A second sensor arrangement responds to the selector and produces operating signals corresponding to the selected conditions. A logic system responds to the signals and, on the basis of the speed and selected conditions, produces electrical indications which represent those valves that must be energized to establish the particular gear ratios that are necessary for operating in the selected conditions. Thus, for example, when the drive condition has been selected, the logic system determines which gear ratio is desired for the particular speed and produces indications selecting the particular valves to be actuated. Driver means then actuate the valves to obtain the resulting gear ratio. The logic system also responds to the extent to which the throttle is opened.
Inventors
- 👤 Masanao Hashimoto
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 15:10
CPC Classifications
F; F16; F16H; F16H61/00; F16H61/02; F16H61/0202; F16H61/0204; F16H61/0206
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
414 words
For a four-forward one-reverse automatic transmission wherein a gear transmission drives wheels in response to operation of a throttle and means including a pluraliTy of hydraulic valves establish a drive ratio in the gear transmission, a control system comprising: means including three shift valves for supplying the hydraulic pressure and relieving the hydraulic pressure from the hydraulic valves according to a predetermined arrangement so that specific gear ratios occurs in response to operation of specific shift valves, first generating means selectively operable by an operator for generating electrical signals indicative of the condition in which the transmission is to operate, second generating means coupled to the throttle and the wheels for generating electrical signals representing an operating condition of the vehicle, logic means response to said first and second generating means for producing electrical values together indicating one of a number of gear shift positions for the transmission in response to the electrical signals from said two generating means, and driver means coupled to said logic means for responding to the electrical values and actuating said three shift valves so as to establish one of a number of specific gear ratios and forward and reverse directions, said first generating means including a plurality of contacts selectively closed by a driver in order to obtain one of six gear ranges; said six gear ranges including reverse gear, neutral, automatic drive range changeable from first to fourth gear, a fixed first gear, a fixed second gear, and a fixed third gear; said second generating means including sensor means coupled to the wheels for producing a signal indicative of the vehicle speed and detecting means responsive to the throttle for generating a signal representative of the load to be placed on the engine, said logic means including three comparators each coupled to said sensing means and said detector means for producing separate logic indications in response to the ratios of the signals applied to each comparator means, said ratios being different for each of the comparator means, said logic means including circuit means responsive to operation of the contacts and said three comparator means for generating the electrical values, said electrical values representing the range determined by the driver and the electrical signal representing the range automatically determined in response to said comparator means, and driving means including three solenoid valves responsive to said logic means, said solenoid valves being actuated in response to electrical values from said circuit means so as to actuate said shift valves.
Claim 2
Dependent Claim
414 words
For a four-forward one-reverse automatic transmission wherein a gear transmission drives wheels in response to operation of a throttle and means including a pluraliTy of hydraulic valves establish a drive ratio in the gear transmission, a control system comprising: means including three shift valves for supplying the hydraulic pressure and relieving the hydraulic pressure from the hydraulic valves according to a predetermined arrangement so that specific gear ratios occurs in response to operation of specific shift valves, first generating means selectively operable by an operator for generating electrical signals indicative of the condition in which the transmission is to operate, second generating means coupled to the throttle and the wheels for generating electrical signals representing an operating condition of the vehicle, logic means response to said first and second generating means for producing electrical values together indicating one of a number of gear shift positions for the transmission in response to the electrical signals from said two generating means, and driver means coupled to said logic means for responding to the electrical values and actuating said three shift valves so as to establish one of a number of specific gear ratios and forward and reverse directions, said first generating means including a plurality of contacts selectively closed by a driver in order to obtain one of six gear ranges; said six gear ranges including reverse gear, neutral, automatic drive range changeable from first to fourth gear, a fixed first gear, a fixed second gear, and a fixed third gear; said second generating means including sensor means coupled to the wheels for producing a signal indicative of the vehicle speed and detecting means responsive to the throttle for generating a signal representative of the load to be placed on the engine, said logic means including three comparators each coupled to said sensing means and said detector means for producing separate logic indications in response to the ratios of the signals applied to each comparator means, said ratios being different for each of the comparator means, said logic means including circuit means responsive to operation of the contacts and said three comparator means for generating the electrical values, said electrical values representing the range determined by the driver and the electrical signal representing the range automatically determined in response to said comparator means, and driving means including three solenoid valves responsive to said logic means, said solenoid valves being actuated in response to electrical values from said circuit means so as to actuate said shift valves.
Claim 3
Dependent Claim
77 words
A system as in claim 1, wherein said circuit means includes a plurality of AND gates each responsive to one of said comparator means and all responsive to operation of one of said contacts indicative of automatic drive, one of said AND gates producing the electrical values operating one of said solenoid valves, the other of said AND gates producing electrical values in cooperating with the first of said AND gates to operate another of said valves.
Claim 4
Dependent Claim
52 words
A system as in claim 2, wherein said circuit means including a pair of inhibitors each connected to said second and third AND gates, said inhibitors being connected to said first AND gate for inhibiting the output of said second and third AND gates when said first AND gate exhibits an output.
Claim 5
Dependent Claim
61 words
A system as in claim 3, wherein one of said inhibitors is connected to a solenoid valve other than the solenoid valve to which said AND gate is connected and a second of said inhibitors is connected to the solenoid valve to which said first AND gate is connected and to the solenoid valve to which the other inhibitor is connected.
Claim 6
Dependent Claim
33 words
A system as in claim 4, wherein said solenoid valves connected to said inhibitors establish four consecutive gears in the transmission on the basis of various combinations of operations of said solenoid valves.
Claim 7
Dependent Claim
21 words
A system as in claim 5, wherein respective ones of said contacts independently operate the valves connected to said inhibitor means.
Claim 8
Dependent Claim
41 words
A system as in claim 6, wheRein said circuit means include means responsive to said contact means for energizing a combination of solenoid valves which operate the shift valves so as to place the transmission in first gear with engine braking.
Claim 9
Dependent Claim
90 words
A system as in claim 7, wherein said circuit means further includes speed comparator means responsive to said sensor means for comparing the speed of the vehicle with a predetermined speed, and inhibitor means responsive to the contact which initiates the first gear with braking and coupled to said speed comparator means for inhibiting the actuation of said shift valves by the solenoid valves producing first gear with braking and alternately selecting the solenoid valves and shift valves which produce second gear when the vehicle speed exceeds the predetermined value.
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) | 1978-09-08 | 1979-03-10 | 1979-09-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-09-08 | 1983-03-10 | 1983-09-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-09-08 | 1987-03-10 | 1987-09-09 | $7700.00 | Window Closed / Lapsed |