US3859873A — Line pressure modulating device for an automatic …

Claim 1

Independent Claim 298 words

A line pressure modulating device for a hydraulic control system of an automatic power transmission of a motor vehicle having an accelerator pedal, the hydraulic control system having a manual selector valve communicating with a source of line pressure, a throttle valve transmitting a throttle pressure representative of the output torque of a vehicle engine, and a governor valve transmitting a governor pressure varying in dependence on the rotational speed of an output shaft of the automatic power transmission, said device comprising, in combination, a line pressure regulator valve communicating with said source of line pressure and responsive to said throttle pressure from said throttle valve for regulating the line pressure in dependence thereon, a first control valve communicating with said line pressure regulator valve and responsive to said governor pressure from said governor valve, a second control valve communicating with said first control valve and said manual selector valve to receive from said manual selector valve line pressure, an electric actuating means to actuate said second control valve, and a first switch electrically connected to said electric actuating means, said first switch being mechanically linked with said accelerator pedal to close when said accelerator pedal is released, said electric actuating means being energized when said first switch is closed for Actuating said second control valve to cause the same to transmit line pressure from said manual selector valve to said first control valve, and said first control valve being movable to a position to transmit line pressure applied thereto to said line pressure regulator valve when said governor pressure is below a first predetermined level, whereby said line pressure regulator valve is movable to a position to decrease the level of line pressure when said accelerator pedal is released while the motor vehicle is at a standstill.

Claim 2

Dependent Claim 298 words

A line pressure modulating device for a hydraulic control system of an automatic power transmission of a motor vehicle having an accelerator pedal, the hydraulic control system having a manual selector valve communicating with a source of line pressure, a throttle valve transmitting a throttle pressure representative of the output torque of a vehicle engine, and a governor valve transmitting a governor pressure varying in dependence on the rotational speed of an output shaft of the automatic power transmission, said device comprising, in combination, a line pressure regulator valve communicating with said source of line pressure and responsive to said throttle pressure from said throttle valve for regulating the line pressure in dependence thereon, a first control valve communicating with said line pressure regulator valve and responsive to said governor pressure from said governor valve, a second control valve communicating with said first control valve and said manual selector valve to receive from said manual selector valve line pressure, an electric actuating means to actuate said second control valve, and a first switch electrically connected to said electric actuating means, said first switch being mechanically linked with said accelerator pedal to close when said accelerator pedal is released, said electric actuating means being energized when said first switch is closed for Actuating said second control valve to cause the same to transmit line pressure from said manual selector valve to said first control valve, and said first control valve being movable to a position to transmit line pressure applied thereto to said line pressure regulator valve when said governor pressure is below a first predetermined level, whereby said line pressure regulator valve is movable to a position to decrease the level of line pressure when said accelerator pedal is released while the motor vehicle is at a standstill.

Claim 3

Dependent Claim 294 words

A line pressure modulating device as claimed in claim 1, in which said line pressure regulator valve has a first port communicating with said source of line pressure through a flow restricting means, a second port communicating with said source of line pressure, a third port communicating with said throttle valve to receive said throttle pressure therefrom, a fourth port communicating with said first control valve, and a fifth port through which fluid under pressure is drained off when said second port is brought into fluid communication with said fifth port, a first valve spool slidably movable within said line pressure regulator valve having a first valve land to control fluid communication between said second port and said fifth port, a second valve land exposed to line pressure from said first port, a third valve land adjacent to said second valve land having a diameter greater than that of said second valve land, said third and second valve lands being exposed to line pressure from said fourth port, and fourth and fifth lands said fourth land having a diameter less than that of said fifth land, said fourth and fifth lands being exposed to line pressure from said third port, and a first compression spring biasing said first valve spool in a direction to decrease the degree of fluid communication between said second port and said fifth port, said first valve spool being movable against the force of said first compression spring in another direction to increase the degree of fluid communication between said second port and said fifth port when line pressure is applied to said fourth port of said line pressure regulator valve, whereby line pressure is reduced when said accelerator pedal is released while the motor vehicle is at a standstill.

Claim 4

Dependent Claim 156 words

A line pressure modulating device as claimed in claim 2, in which said first control valve has a sixth port communicating with said second control valve, a seventh port communicating with said fourth port of said line pressure regulator valve, and an eighth port communicating with said governor valve to receive therefrom governor pressure, a second valve spool having a sixth valve land to control communication between said seventh and eighth ports, said second valve spool having a seventh valve land exposed to said governor pressure from said eighth port, and a second compression spring biasing said second valve spool in one direction to establish fluid communication between said sixth and seventh ports, said second valve spool being movable by the force of said second compression spring to establish fluid communication between said sixth and seventh ports when said governor pressure is below said first predetermined level indicating that the motor vehicle is at a standstill.

Claim 5

Dependent Claim 139 words

A line pressure modulating device as claimed in claim 3, in which said second control valve has a ninth port communicating with said manual selector valve to receive fluid under line pressure therefrom and a tenth port communicating with said sixth port of said first control valve, a third valve spool having an eighth valve land to control fluid communication between said ninth and tenth ports, and a third compression spring biasing said third valve spool in one direction to interrupt fluid communication between said ninth and tenth ports, said third valve spool engaging with said electric actuating means and being movable against the force of said third compression spring thereby in another direction to estaBlish fluid communication between said ninth and tenth ports to transmit line pressure to said sixth port when said electric actuating means is energized.

Claim 6

Dependent Claim 19 words

A line pressure modulating device as claimed in claim 1, in which said electric actuating means is a solenoid.

Claim 7

Dependent Claim 120 words

A line pressure modulating device as claimed in claim 1, further comprising a kickdown valve which is interposed between said first and second control valves, and a second switch electrically connected to said electric actuating means in parallel with said first switch, said second switch being mechanically linked with said accelerator pedal and closing when said accelerator pedal is depressed beyond a second predetermined value, said kickdown valve communicating with said throttle valve and being exposed to throttle pressure therefrom, whereby when said throttle pressure exceeds a third predetermined value, said kickdown valve is actuated to transmit line pressure therefrom to cause a kickdown operation of the automatic transmission, and block fluid communication between said first and second control valves.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1978-01-13	1978-07-15	1979-01-14	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1982-01-13	1982-07-15	1983-01-14	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1986-01-13	1986-07-15	1987-01-14	$7700.00	Window Closed / Lapsed

Line pressure modulating device for an automatic power transmission

Abstract

Inventors

Bibliographic Details

Claims Analysis

References Cited (Backward Citations)

USPTO Annuity & Maintenance Windows

Assigned Categories & Tags

Assign Category Tag