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US3733932A Expired / Lapsed US ⏱️ 0.0 years remaining

Hydraulic control system for automatic transmissions

Assignee: Toyota Motor Corp
•
Filing: 1971-05-05
•
Granted: 1973-05-22
•
Expires: 1991-05-05
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Abstract

Abstract A hydraulic control system for automatic transmissions comprising hydraulic servo means operable to actuate clutch means of the transmission assembly, a pressure oil source for generating pressure oil to be supplied to said hydraulic servo means, a pressure control valve adapted to control pressure oil from said pressure oil source to obtain a required line pressure, a throttle valve for generating a throttle pressure corresponding to the opening of the engine throttle valve, a governor valve generating a governor pressure corresponding to the vehicle speed, a manual valve for distributing the line pressure to a required hydraulic servo circuit to achieve a required transmission condition, a 1 - 2 shift valve for shifting between the first speed and second speed conditions of the transmissions according to the vehicle running conditions regulated by the throttle pressure and governor pressure, a 2 - 3 shift valve for shifting between the second speed and third speed conditions of the transmission according to the vehicle running conditions, accumulator means for moderating the application of the line pressure to a servo oil chamber of the clutch means for the third speed, a 2 - 3 timing valve for determining the timing of up or down shift in the second and third speed conditions of the transmission, and an orifice control valve adapted to control the flow rate of the line pressure supplied to the servo oil chamber in the clutch means for the second speed so as to lessen the shift shock. The throttle valve is so arranged that when the opening of the engine throttle valve is less than 1/4 of the full opening, it functions to drain pressure oil from the pressure oil source by a pilot valve in cooperation with a throttle lever thereby to change the controlling action of the pressure control valve so as to obtain an extremely low constant line pressure from said pressure control valve, this valve being also so arranged that when the transmission is in the third speed condition, the controlling action of said valve is further changed by the line pressure supplied to the servo oil chamber in the clutch means for the third speed so as to obtain a still lower line pressure.

Inventors

  • 👤 S Uozumi
  • 👤 I Sakai

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-10-25 00:54
CPC Classifications
F; F16; F16H; F16H61/00; F16H61/02; F16H61/0262; F16H61/0276; F16H61/029; F16H61/0021; F16H61/68; F16H61/684; Y; Y10; Y10T; Y10T74/00; Y10T74/19; Y10T74/19219; Y10T74/19377; Y10T74/19386; Y10T74/19405

Claims Analysis

Total Claims: 9
Claim 1
Independent Claim 308 words
In a hydraulic control system for an automatic transmission for an engine driven vehicle including an engine, a throttle for said engine, means enabling positioning of said throttle to control said engine, with positioning of said throttle to a first position effecting a lowermost level of engine output and with positioning of said throttle to a second position effecting an uppermost level of engine output, speed change gear means connecting said engine to drive said vehicle, hydraulic servo means for operating said gear change means, a pressure oil source for generating pressure oil supplied to operate said hydraulic servo means, a pressure level control arrangement for controlling the pressure level of oil supplied to said servo means from said oil supply, and conduit means connected to supply pressure oil to said servo means from said oil source through said control arrangement, said control arrangement comprising a pressure control valve controlling the pressure level of pressure oil from said oil source, a first oil chamber in said pressure control valve configured to effect operation of said valve to control the pressure level of oil from said oil source in accordance with the pressure level in said first oil chamber, a throttle valve comprising a movable plug, means for effecting displacement of said plug in accordance with the position of the throttle of said engine, a second oil chamber in said throttle valve, means including said plug for controlling the pressure level in said second chamber in accordance with the position of said engine throttle, and oil passage means connecting said second oil chamber and said first oil chamber to control the pressure in said first oil chamber in accordance with the pressure in said second oil chamber thereby to effect control of the pressure level of oil from said source in accordance with the position of said engine throttle.
Claim 2
Dependent Claim 308 words
In a hydraulic control system for an automatic transmission for an engine driven vehicle including an engine, a throttle for said engine, means enabling positioning of said throttle to control said engine, with positioning of said throttle to a first position effecting a lowermost level of engine output and with positioning of said throttle to a second position effecting an uppermost level of engine output, speed change gear means connecting said engine to drive said vehicle, hydraulic servo means for operating said gear change means, a pressure oil source for generating pressure oil supplied to operate said hydraulic servo means, a pressure level control arrangement for controlling the pressure level of oil supplied to said servo means from said oil supply, and conduit means connected to supply pressure oil to said servo means from said oil source through said control arrangement, said control arrangement comprising a pressure control valve controlling the pressure level of pressure oil from said oil source, a first oil chamber in said pressure control valve configured to effect operation of said valve to control the pressure level of oil from said oil source in accordance with the pressure level in said first oil chamber, a throttle valve comprising a movable plug, means for effecting displacement of said plug in accordance with the position of the throttle of said engine, a second oil chamber in said throttle valve, means including said plug for controlling the pressure level in said second chamber in accordance with the position of said engine throttle, and oil passage means connecting said second oil chamber and said first oil chamber to control the pressure in said first oil chamber in accordance with the pressure in said second oil chamber thereby to effect control of the pressure level of oil from said source in accordance with the position of said engine throttle.
Claim 3
Dependent Claim 129 words
A hydraulic contrOl system according to claim 1, wherein said gear change means include a high speed gear ratio, there being provided means for supplying or excluding oil pressure to said hydraulic servo means thereby to engage or disengage said high speed gear ratio, said system further comprising a third oil chamber in said pressure control valve, means for applying to said third chamber oil pressure representative of said pressure supplied to said hydraulic servo means for engaging and disengaging said high speed gear ratio, said oil pressure applied to said third chamber operating simultaneously with the pressure in said first oil chamber to effect further control of the level of oil pressure from said oil source in dependence upon engagement or disengagement of said high speed gear ratio.
Claim 4
Dependent Claim 34 words
A hydraulic control system according to claim 2, wherein the pressure in said third oil chamber acts upon said pressure control valve in a manner opposed to the pressure in said first oil chamber.
Claim 5
Dependent Claim 43 words
A hydraulic control system according to claim 2, wherein said pressure control valve is structurally configured to lower the level of said oil source pressure supply when said high speed gear ratio is engaged and to raise said level when it is disengaged.
Claim 6
Dependent Claim 71 words
A hydraulic control system according to claim 2, wherein said pressure control valve comprises a plug movable in response to pressures in said first and third oil chambers and means for venting pressure from said pressure oil source thereby to control said oil source pressure supply level, said movable plug being operable to open and close said venting means in accordance with said pressures in said first and third oil chambers.
Claim 7
Dependent Claim 71 words
A hydraulic control system according to claim 1, wherein said throttle valve is structurally configured to effect lowering of the level of said oil source pressure supply when said engine throttle is positioned to effect a level of engine output below a predetermined level, said predetermined level being between said lowermost and said uppermost level, and to effect raising of said supply level when said throttle is above said predetermined level.
Claim 8
Dependent Claim 34 words
A hydraulic control system according to claim 6, wherein said predetermined level is selected to be one-quarter of the full range of said engine throttle positions from said first position to said second position.
Claim 9
Dependent Claim 54 words
A hydraulic control system according to claim 1, comprising means for venting oil pressure in said second oil chamber, said moveable plug of said throttle valve being operable to open and close said venting means to control the pressure in said second oil chamber and thereby control the pressure in said first oil chamber.

References Cited (Backward Citations)

No citation records indexed.

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1976-05-21 1976-11-20 1977-05-22 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1980-05-21 1980-11-20 1981-05-22 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1984-05-21 1984-11-20 1985-05-22 $7700.00 Window Closed / Lapsed

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