DRIVE MODE SELECTION SYSTEM FOR TRANSMISSIONS

• US 3,695,121 A
• Filed: 10/05/1970
• Issued: 10/03/1972
• Est. Priority Date: 10/05/1970
• Status: Expired due to Term

• Current Assignee: Donald H. Lee, Gordon D. Corrigan, Howard E. Olsen, Robert J. Petry
• Original Assignee: Donald H. Lee, Gordon D. Corrigan, Howard E. Olsen, Robert J. Petry
• Inventors: Corrigan, Gordon D., Petry, Robert J., Lee, Donald H., Olsen, Howard E.
• Primary Examiner(s): Husar, C. J.
• Application Number:
  US05/078,077
• Time in Patent Office: 729 Days
• Field of Search: 74/753 91/DIG.1
• US Class Current: 475/132
• CPC Class Codes: F15B 11/121 providing distinct intermediate positions F15B11/13 takes precedence
• CPC Class Codes: F15B 13/0402 for linearly sliding valves, e.g. spool valves
• CPC Class Codes: F15B 13/0431 the electrical control resulting in an on-off function
• CPC Class Codes: F16H 2061/026 On-off solenoid valve
• CPC Class Codes: F16H 59/08 Range selector apparatus
• CPC Class Codes: F16H 59/105 consisting of electrical switches or sensors
• CPC Class Codes: F16H 61/0286 Manual valves
• CPC Class Codes: F16H 61/12 Detecting malfunction or potential malfunction, e.g. fail safe in control of hydrostatic gearing F16H61/4192; Circumventing or fixing failures
• CPC Class Codes: Y10S 74/01 Hydraulic control systems automatic automotive controls

Abstract

Transmission operation selector system in which a selector valve is moved to predetermined control positions by the force of line pressure acting on a differential area of the selector valve and the opposing force of a signal pressure in a control chamber at one end of the valve. Signal pressure is controlled by solenoid operated valves operatively connected to a selector switch controlled by the vehicle operator. A line feed valve which controls the supply of operating fluid to the selector valve is controlled by a solenoid operated valve and cooperating pressure switches to cut off the feed of the fluid to the selector valve to prevent vehicle motion other than that selected when any one solenoid has failed.

Claims

1. In a drive mode selector system for an automatic transmission having a plurality of predetermined operations comprising low speed forward drive and automatic change speed forward drive, a hydraulically operated selector valve having a shiftable valve element, a source of fluid pressure, fluid conducting means connecting said source to said selector valve so that the pressure provided by said source provides a force urging said shiftable valve element in a predetermined direction, said selector valve having an expansible control chamber hydraulically connected to said fluid pressure source for receiving pressure fluid therefrom which urges said shiftable valve element in an opposite direction, a series of spaced exhaust ports formed in said selector valve communicating with said expansible control chamber, valve means normally closing each of said ports to permit the pressure of the fluid from said source to build up in said expansible control chamber and thereby urge said shiftable valve element to a first position to condition the transmission for a forward drive operation, and operator means for said valve means selectively opening any of said ports to decay the pressure in said expansible control chamber so that said shiftable valve element will move to a second position to close said opened port thereby conditioning the transmission for another forward drive operation.

2. The selector system defined in claim 1 wherein said first position of said shiftable valve element is established by a stop mechanism which mechanically contacts said shiftable valve element to condition the transmission for low range forward drive, said shiftable valve element having first and second lands with opposing cross-sectional areas providing a differential land area operatively connected to said source so that fluid pressure can exert a force on said shiftable valve element to move said shiftable valve element to said second position to condition the transmission for automatic change-speed forward drive when a first of said exhaust ports is opened by said operator means, said shiftable valve element having a control land which opens said expansible chamber to exhaust in response to increased pressure in said expansible chamber by uncovering said first exhaust port so that opposing forces on said shiftable valve element will maintain said shiftable valve element in said second forward drive position.

3. In a drive mode selector system for an automatic transmission control, a selector valve, a source of fluid pressure, fluid conducting means connecting said source to said selector valve, said valve having a shiftable valve element with lands having facing end areas providing an area differential so that pressure from said source fed to said valve will urge said valve element in a predetermined direction, an expansible control chamber formed by said shiftable valve element, a series of exhaust ports communicating with said expansible control chamber, valve means for closing and opening each of said exhaust ports, control means operatively connected to said valve means to effect the opening of any of said ports thereby allowing the pressure to decay in said expansible control chamber so that said shiftable valve element is moved by the force exerted by fluid pressure on said differential area of said lands to a position in which said opened port is blocked by said shiftable valve element to thereby seal said expansible control chamber so that the hydraulic forces acting on said shiftable valve element maintain said shiftable valve element in a predetermined position.

4. In a drive mode selection system for a transmission comprising a hydraulically operated transmission control, said control including a drive mode selector valve having a hydraulically actuated selector valve element, a source of operating fluid for said selector valve, a line feed valve operatively disposed between said source and said selector valve, said line feed valve having a first control chamber with an exhaust, control means for opening and closing said control chamber with respect to said exhaust, a second control chamber formed by said selector valve element, fluid conducting means hydraulically connecting said second control chamber to said line feed valve, a plurality of openings spaced longitudinally in said second control chamber, exhaust means operatively connected to each of said openings, control means for each of said spaced openings to normally block said openings, operator means for said control means to effect the selective opening and closing of each of said openings to control the pressure in said control chamber to thereby position said selector valve element in predetermined positions, first and second fluid passage means hydraulically connecting said selector valve to said transmission controls, and first switch means operatively connected to said first fluid passage means and to said line feed valve for exhausting said line feed valve only when said selector valve element is in a first predetermined position and second switch means operatively connected to said second fluid passage means and to said line feed valve for exhausting said line feed valve only when said selector valve element is in another predetermined position so that said transmission will stay in the same drive direction or become neutralized in the event that any one of said control means for said spaced openings fails.

5. The drive mode selection system for a transmission as set forth in claim 4 in which said control means for each of said spaced openings comprises valve means, a solenoid for each of said valve means, a source of electrical energy, said solenoids being operatively connected to said source of electrical energy, a control switch operatively connected to said source of electrical energy and to each of said solenoids, said switch having contact means selectively movable to predetermined positions to control the opening and closing of said openings and thereby the position of said selector valve.

6. A control for an automatic change speed transmission for vehicles comprising a source of hydraulic pressure, hydraulic controls for automatically changing the input/output speed ratio of the transmission in accordance with operating signals such as transmission output speed and vehicle engine torque demand, a line feed valve operatively connected to said source, selector valve means for directing operating fluid to said hydraulic controls to selectively condition the transmission for predetermined operations such as reverse, low forward drive and automatic change-speed forward drive, fluid passage means for hydraulically connecting said line feed valve and said selector valve, said selector valve means having a shiftable valve element and having a control chamber operatively connected to said fluid passage means, a plurality of solenoid controlled valves operatively connected to said control chamber to control the volume and pressure of fluid therein, a source of electrical energy, a selector switch operatively connected to said source of electrical energy and to said solenoid valves, said selector switch having a switch element movable to any one of a predetermined number of selected positions to selectively operate said solenoid valves to thereby control the volume and pressure in said control chamber to thereby control the position of said shiftable valve element.

7. A control for an automatic change speed transmission having a plurality of ratio-changing operations comprising a source of pressurized hydraulic fluid, hydraulic control means for automatically changing the transmission input/output speed ratio for forward drive operation, a selector valve having a valve element movable to predetermined positions for directing hydraulic fluid to said control means so that said control means selectively conditions said transmission for different predetermined operations, a fluid feed line connected to said selector valve and to said fluid pressure source to supply operating fluid to said selector valve to exert a biasing force on said valve element biasing said valve element in a first direction, a line feed valve operatively connected in said fluid feed line for controlling the feed of fluid from said source to said selector valve through said fluid feed line, said selector valve having an expansible control chamber hydraulically connected to said fluid feed line for receiving pressure fluid from said source that exerts a biasing force on said movable valve element to urge said valve element in a direction opposite to said first direction, said expansible chamber having a plurality of openings therein for exhausting pressure fluid from said chamber, a control valve element for each of said openings, manually operable switch means for selectively actuating each of said control valve elements to accordingly effect a change in pressure in said expansible control chamber and a change in position of said selector valve element whereby said transmission controls are conditioned for selected operations, and additional control means operatively connected to said selector valve and to said line feed valve for moving said line feed valve to a position to cut off the feed of pressure fluid from said source to said selector valve to thereby change the transmission from a driving condition to a neutral condition when said selector valve element is in a predetermined position.

8. A control for an automatic change speed transmission comprising a source of pressurized hydraulic fluid, hydraulic control means for automatically changing the transmission input/output speed ratio, a selector valve, a plurality of fluid conducting passages operatively connecting said selector valve and said hydraulic control means, said selector valve having a selectively movable valve element for directing hydraulic fluid to said control means through said passages to selectively condition said transmission for different predetermined operations such as reverse, low range forward drive and automatic change speed forward drive, a fluid conducting line connecting said selector valve and said source of hydraulic fluid, a line feed valve for feeding fluid from said source to said selector valve through said fluid conducting line, said selector valve having an expansible control chamber hydraulically connected to said fluid conducting line for receiving pressure fluid that exerts a biasing force on said selectively movable valve element, said expansible chamber having a plurality of ports therein for exhausting pressure fluid from said chamber, a control valve element for each of said ports and control means for selectively operating each of said control valve elements to accordingly effect a change in pressure in said expansible chamber and a change in position of said selector valve element so that said transmission controls are conditioned for selected operations, said fluid conducting passages including a reverse line charged with pressure fluid when said selector valve element is in a reverse drive position and a forward drive line charged with pressure fluid when said selector valve element is in a forward drive position, said control means comprising a solenoid for each of said control valve elements, a source of electrical energy, manually operable switch means for selectively connecting said solenoids to said source for selectively opening said ports to thereby effect a prEssure change in said expansible chamber, said line feed valve having a control chamber, an exhaust for said last-mentioned control chamber, solenoid operated valve means for opening said last-mentioned control chamber to said exhaust, first pressure switch means operatively connected to said reverse line and to said solenoid to effect the establishment of pressure in said control chamber in the event that said control switch is set for forward drive and the selector valve is in reverse to effect the movement of said line feed valve to cut off supply of fluid to said selector valve to thereby neutralize said transmission, second pressure switch means operatively connected to said forward drive line and to said solenoid to effect the establishment of pressure in said control chamber in the event that said control switch is set for reverse drive and said selector valve is in forward drive to cut off the supply of fluid to said selector valve to thereby condition said transmission for neutral operation.