Patent US3710651A successfully refreshed from Google Patents.
US3710651A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Line pressure regulating system for automatic power transmission
Assignee: Nissan Motor Co Ltd
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Filing: 1971-03-08
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Granted: 1973-01-16
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Expires: 1991-03-08
Abstract
Abstract A system for regulating a line pressure in a hydraulic control circuit for an automatic power transmission that is capable of reducing the line pressure to a sufficiently low level to prevent shift shock at the time of gear shifting. When gear shifting is to be effected, a gear shift command signal is supplied to an electronic line pressure control circuit including a monostable multivibrator to keep the multivibrator in a metastable state for a predetermined period of time. During the time period the electronic line pressure control circuit generates a line pressure reduction signal which is supplied to a pressure regulating valve arrangement, thereby reducing the line pressure to the sufficiently low level. The line pressure is normally maintained at a sufficiently high level to prevent slippage of the friction-drive-establishing devices of the automatic power transmission.
Inventors
- 👤 N Irie
- 👤 N Marumo
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 15:05
CPC Classifications
F; F16; F16H; F16H61/00; F16H61/0021; F16H61/04; F16H61/0437; G; G05; G05D; G05D16/00; G05D16/20; G05D16/2093; G05D16/2095; G05D16/2097; F16H61/02; F16H61/0202; F16H61/0251; F16H2061/026
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
289 words
A system for regulating a line pressure in a hydraulic control circuit for an automatic power transmission, for a motor vehicle having an internal combustion engine provided with an intake manifold and a throttle valve, having a plurality of friction-drive-establishing devices, comprising: a first means for producing a first electric signal corresponding to vehicle speed, a second means for producing a second electric signal corresponding to a throttle opening, a first circuit means for determining proper reduction gear ratios under different driving conditions of the motor vehicle in response to said first and second electric signals to produce a gear shift command signal, said first circuit means consisting of a Schmidt Trigger circuit having a common input connected to said first and second means, a first electronic actuator responsive to said gear shift command signal for operating the hydraulic control circuit so as to effect a transition to a proper reduction gear ratio, a second circuit means for producing a line pressure reduction signal for a predetermined length of time in response to said gear shift command signal, said second circuit means consisting of means for producing a trigger pulse in response to said gear shift command signal and means for producing said line pressure reduction signal in response to said trigger pulse, a second electronic actuator responsive to said line pressure reduction signal, and a hydraulic control means for reducing said line pressure to a predetermined level sufficiently low by means of said second electronic actuator in order to prevent shift shock, said hydraulic control means including a means for sensing a vacuum in the intake manifold and said line pressure being normally maintained at a sufficiently high level in order to prevent slippage of the friction-drive-establishing devices.
Claim 2
Independent Claim
289 words
A system for regulating a line pressure in a hydraulic control circuit for an automatic power transmission, for a motor vehicle having an internal combustion engine provided with an intake manifold and a throttle valve, having a plurality of friction-drive-establishing devices, comprising: a first means for producing a first electric signal corresponding to vehicle speed, a second means for producing a second electric signal corresponding to a throttle opening, a first circuit means for determining proper reduction gear ratios under different driving conditions of the motor vehicle in response to said first and second electric signals to produce a gear shift command signal, said first circuit means consisting of a Schmidt Trigger circuit having a common input connected to said first and second means, a first electronic actuator responsive to said gear shift command signal for operating the hydraulic control circuit so as to effect a transition to a proper reduction gear ratio, a second circuit means for producing a line pressure reduction signal for a predetermined length of time in response to said gear shift command signal, said second circuit means consisting of means for producing a trigger pulse in response to said gear shift command signal and means for producing said line pressure reduction signal in response to said trigger pulse, a second electronic actuator responsive to said line pressure reduction signal, and a hydraulic control means for reducing said line pressure to a predetermined level sufficiently low by means of said second electronic actuator in order to prevent shift shock, said hydraulic control means including a means for sensing a vacuum in the intake manifold and said line pressure being normally maintained at a sufficiently high level in order to prevent slippage of the friction-drive-establishing devices.
Claim 3
Dependent Claim
108 words
A system according to claim 1, in which said means for producing a trigger pulse comprises a series combination of an invertor, a first differentiator and a first diode and a series combination of a second differentiator and a second diode, and said means for producing said line pressure reduction signal in response to said trigger pulse comprises a monostable multivibrator adapted to be kept in metastable state, said two series combinations being connected in parallel with the input of said monostable multivibrator and the length of time during which said monostable multivibrator is kept in its metastable state determining the duration of said line pressure reduction signal.
Claim 4
Dependent Claim
30 words
A system according to claim 2, in which said length of time increases as said vehicle speed rises and further increases in proportion to an increase in said throttle opening.
Claim 5
Dependent Claim
25 words
A system according to claim 1, in which said second electronic actuator comprises a solenoid coil connected to said second circuit means and a plunger.
Claim 6
Dependent Claim
380 words
A system according to claim 1, in which said hydraulic control means comprises a first main line leading from the outlet port of an engine driven fluid pump, a regulator valve connected to said first main line and having an axially slidable spool therein, said spool being slidable in one direction to increase the pressure in said first main line and in the opposite direction to reduce the pressure in said first main line tending to slide said spool in the opposite direction, a vacuum valve connected through a branch line to said first main line and having an axially slidable spool therein, said spool being operatively connected to the intake manifold vacuum seNsor in such a manner that as the intake manifold vacuum increases said spool slides in one direction and as the intake manifold vacuum decreases said spool slides in the opposite direction, a second main line connected to said vacuum valve in such a manner that when said spool slides in one direction the pressure in said second line decreases and when said spool slides in the opposite direction the pressure increases an amplifier valve having an axially slidable spool and connected to said second main line in such a manner that the pressure in said second main line exerts a force on said spool tending to slide it in one direction, said spool being operatively connected to said regulator valve spool in such a manner that when said amplifier valve spool slides in one direction said regulator valve spool slides also in said one direction, a third line connected to said second line through an orifice, said third main line being connected to said regulator valve in such a manner that the pressure in said third main line tends to cause the regulator valve spool to slide in said opposite direction, a nozzle connected to said third main line, said nozzle being operatively closed by means of said plunger of the second electronic actuator in response to said line pressure reduction signal, whereby when said solenoid coil is energized by said line pressure reduction signal, the pressure in said third main line increases so as to cause said regulator valve spool to slide in said opposite direction and reduce the pressure in said first main line.
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) | 1976-01-16 | 1976-07-17 | 1977-01-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-01-16 | 1980-07-17 | 1981-01-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-01-16 | 1984-07-17 | 1985-01-16 | $7700.00 | Window Closed / Lapsed |