Automatic shift for a transmission

Claim 2

In a transmission; an input element; an output element; a multi ratio drive gear unit connecting said input element to said output element having a low and a high fluid actuated friction device respectively providing a low and a high ratio drive selectively operable for establishing said low and high ratio drives; a source of fluid at a regulated pressure; a governor providing a governor pressure proportional to the operating speed of one of said elements; a manual valve connected to said source, having a manual low signal line and a low-high signal line and operative in a low position connecting the source of fluid pressure to said manual low signal line and in a low-high position connecting the source of fluid pressure to said low-high signal line and in each position exhausting the other of said connected lines; automatic control valve means operatively connected to said governor and said manual valve and operative in response to governor pressure to shift between a downshifted and an upshifted position and operative in either position in response to said manual low signal line pressure to supply fluid pressure to said low device to establish low drive and operative in response to said low-high signal line pressure in a downshifted position to supply fluid pressure to said low device to establish low drive and in an upshifted position to exhaust said low drive device and supply fluid pressure to said high drive device and inhibitor means operatively connected to said manual valve, automatic control valve means and said governor for controlling said manual valve, to permit at any of said operating speeds, when said automatic control valve means is downshifted, a low-high position to low position manual shift and to inhibit above a predetermined operating speed, when said automatic control valve is upshifted, a low-high position to low position manual shift.

Claim 3

In a transmission; an input element; an output element; a multi ratio drive gear unit connecting said input element to said output element having a low and a high fluid actuated friction device respectively providing a low and a high ratio drive selectively operable for establishing said low and high ratio drive; a source of fluid at a regulated pressure; a governor providing a governor pressure proportional to the operating speed of one of said elements; a manual valve connected to said source, having a manual low signal line and a low-high signal line and operative in a first position connecting the fluid pressure to said manUal low signal line and exhausting said low-high signal line and in a second position connecting the fluid pressure to said low-high signal line and exhausting said manual low signal line; an automatic shift valve having an automatic low signal line and a high ratio line connected to said high friction device and operatively connected to said manual valve and biased to a downshift position connecting said low-high signal line to said automatic low signal line and connected to said governor and operative in response to governor pressure to upshift to an upshift position connecting said low-high signal line to said high ratio line; a shuttle valve having a low ratio line connected to said low ratio device connected to said manual low signal line and said automatic low signal line and operative in response to manual low signal line pressure to connect said manual low signal line to said low ratio line to establish low drive and operative in response to said automatic low signal line pressure to connect said automatic low signal line to said low ratio line to establish low drive.

Claim 4

In a transmission; an input element; an output element; a multi ratio drive gear unit connecting said input element to said output element having a low and a high fluid actuated friction device respectively providing a low and a high ratio drive selectively operable for establishing said low and high ratio drive; a source of fluid at a regulated pressure; a governor providing a governor pressure proportional to the operating speed of one of said elements; a manual valve connected to said source, having a manual low signal line and a low-high signal line and operative in a first position connecting the fluid pressure to said manUal low signal line and exhausting said low-high signal line and in a second position connecting the fluid pressure to said low-high signal line and exhausting said manual low signal line; an automatic shift valve having an automatic low signal line and a high ratio line connected to said high friction device and operatively connected to said manual valve and biased to a downshift position connecting said low-high signal line to said automatic low signal line and connected to said governor and operative in response to governor pressure to upshift to an upshift position connecting said low-high signal line to said high ratio line; a shuttle valve having a low ratio line connected to said low ratio device connected to said manual low signal line and said automatic low signal line and operative in response to manual low signal line pressure to connect said manual low signal line to said low ratio line to establish low drive and operative in response to said automatic low signal line pressure to connect said automatic low signal line to said low ratio line to establish low drive.

Claim 5

The invention defined in claim 2 and said governor being connected to said input element and providing a governor pressure proportional to input speed and said automatic shift valve having a small area actuator and a large area actuator and said governor pressure acting on said small area actuator when the automatic shift valve is downshifted and on the large area actuator when the automatic shift valve is upshifted to correct for the low-high shift speed change and provide hysteresis resulting in a lower downshift speed than upshift speed relative to output speed.

Claim 6

The invention defined in claim 3 and said automatic shift valve having a large diameter bore portion and a small diameter bore portion with a step therebetween, a valve element having at one end a large diameter portion in said large diameter bore portion providing said large area and a small diameter governor plug having said small area mounted in said small diameter bore portion having a closed end and receiving said plug to provide a small area chamber between said plug and closed end continuously connected to said governor and receiving governor pressure to urge said plug and valve element to upshift and a large area chamber at said step and between said plug and one end of said valve element and means to exhaust said large chamber when the shift valve is downshifted and connected to said governor to said large chamber when said shift valve element is upshifted so governor pressure acts on said larger area.

Claim 7

In a transmission; an input element; an output element; a multi ratio drive gear unit connecting said input element to said output element having a low and a high fluid actuated friction device respectively providing a low and a high ratio drive selectively operable for establishing said low and high ratio drives; a source of fliud at a regulated pressure; a governor providing a governor pressure proportional to the operating speed of one of said elements; a manual valve connected to said source, having a manual low signal line and a low-high signal line and operative in a low position connecting the source of fluid pressure to said manual low signal line and exhausting said low-high signal line and in a low-high position connecting the source of fluid pressure to said low-high signal line and exhausting said manual low signal line; an automatic shift valve having an automatic low signal line and a high ratio line connected to said high friction device and operatively connected to said manual valve and biased to a downshift position connecting said low-high signal line to said automatic low signal line and connected to said governor and operative in response to governor pressure to upshift to an upshift position connecting said low-high signal line to said high ratio line; a shuttle valve having a low ratio line connected to said low ratio device and connected to said manual low signal line and said automatic low signAl line and operative in response to said manual low signal line pressure to supply fluid pressure to said low ratio line to establish low drive and operative in response to automatic low signal line pressure to supply fluid pressure to said low ratio line to establish low drive; and inhibitor means connected to said manual valve, the automatic shift valve and said governor operative to normally permit manual valve shifting between said low position and low-high position when the automatic valve is downshifted and inhibiting a manual valve shift from said low-high position to said low position when the automatic valve is upshifted to prevent a manual high to low ratio drive shift above a predetermined operating speed.

Claim 8

In a transmission; an input element; an output element; a multi ratio drive gear unit connecting said input element to said output element having a low and a high fluid actuated friction device respectively providing a low and a high ratio drive selectively operable for establishing said low and high ratio drives; a source of fliud at a regulated pressure; a governor providing a governor pressure proportional to the operating speed of one of said elements; a manual valve connected to said source, having a manual low signal line and a low-high signal line and operative in a low position connecting the source of fluid pressure to said manual low signal line and exhausting said low-high signal line and in a low-high position connecting the source of fluid pressure to said low-high signal line and exhausting said manual low signal line; an automatic shift valve having an automatic low signal line and a high ratio line connected to said high friction device and operatively connected to said manual valve and biased to a downshift position connecting said low-high signal line to said automatic low signal line and connected to said governor and operative in response to governor pressure to upshift to an upshift position connecting said low-high signal line to said high ratio line; a shuttle valve having a low ratio line connected to said low ratio device and connected to said manual low signal line and said automatic low signAl line and operative in response to said manual low signal line pressure to supply fluid pressure to said low ratio line to establish low drive and operative in response to automatic low signal line pressure to supply fluid pressure to said low ratio line to establish low drive; and inhibitor means connected to said manual valve, the automatic shift valve and said governor operative to normally permit manual valve shifting between said low position and low-high position when the automatic valve is downshifted and inhibiting a manual valve shift from said low-high position to said low position when the automatic valve is upshifted to prevent a manual high to low ratio drive shift above a predetermined operating speed.

Claim 9

The invention defined in claim 5 and said inhibitor means having a cam element variably positioned by said governor and being connected to said low-high signal line of said manual valve and said automatic low signal line of said automatic shift valve and said automatic low signal overcoming said governor and positioning said cam element against a stop member positioned by said low-high signal pressure.

Claim 10

In a transmission; an input element; an output element; a multi ratio drive gear unit connecting said input element to said output element having a lower, a low and a high fluid actuated friction device respectively providing a lower, a low and a high ratio device selectively operable for establishing said lower, low and high ratio drives; a source of fluid at a regulated pressure; a governor providing a governor pressure proportional to the speed of one of said elements; a manual valve connected to said source, having a lower apply line connected to said lower fluid actuator friction device, a manual low signal line and a low-high signal line and operative in a lower position connecting the source of fluid pressure to said lower apply line to engage said lower ratio drive, in a low position connecting the source of fluid pressure to said manual low signal line and in a low-position connecting the source of fluid pressure to said low-high signal line and in each position exhausting the other of said connected lines; automatic control valve means operatively connected to said governor and said manual valve and operative in response to governor pressure to shift between a downshifted and an upshifted position and operative in either position in response to said manual low signal line pressure to supply fluid pressure to said low device to establish low drive and operative in response to said low-high signal line pressure in a downshifted position to supply fluid pressure to said low device to establish low drive and in an upshifted position to exhaust said low drive device and supply fluid pressure to said high drive device and inhibitor means operatively connected to said manual valve, automatic shift valve means and said governor controlling said manual valve to inhibit, above a predetermined speed, a manual shift from said low position to said lower position, to permit at any speed, when said automatic shift valve means is downshifted, a manual low-high position to low position shift and to inhibit above a predetermined speed, when said shift valve is upshifted, a manual low-high position to low position shift.

Claim 11

In a transmission; an input element; an output element; a multi ratio drive gear unit connecting said input element to said output element having a lower, a low and a high fluid actuated friction device respectively providing a lower, a low and a high ratio device selectively operable for establishing said lower, low and high ratio drives; a source of fluid at a regulated pressure; a governor providing a governor pressure proportional to the speed of one of said elements; a manual valve connected to said source, having a lower apply line connected to said lower fluid actuator friction device, a manual low signal line and a low-high signal line and operative in a lower position connecting the source of fluid pressure to said lower apply line to engage said lower ratio drive, in a low position connecting the source of fluid pressure to said manual low signal line and in a low-position connecting the source of fluid pressure to said low-high signal line and in each position exhausting the other of said connected lines; automatic control valve means operatively connected to said governor and said manual valve and operative in response to governor pressure to shift between a downshifted and an upshifted position and operative in either position in response to said manual low signal line pressure to supply fluid pressure to said low device to establish low drive and operative in response to said low-high signal line pressure in a downshifted position to supply fluid pressure to said low device to establish low drive and in an upshifted position to exhaust said low drive device and supply fluid pressure to said high drive device and inhibitor means operatively connected to said manual valve, automatic shift valve means and said governor controlling said manual valve to inhibit, above a predetermined speed, a manual shift from said low position to said lower position, to permit at any speed, when said automatic shift valve means is downshifted, a manual low-high position to low position shift and to inhibit above a predetermined speed, when said shift valve is upshifted, a manual low-high position to low position shift.

Claim 12

In a transmission; an input element; an output element; a multi ratio drive gear unit connecting said input element to said output element having a lower, a low and a high fluid actuated friction device respectively providing a lower, a low and a high ratio drive selectively operable for establishing said lower, low and high ratio drives; a source of fluid at a regulated pressure; a governor providing a governor pressure proportional to the speed of one of said elements; a manual valve connected to said source, having a lower apply line connected to said lower fluid actuated friction device, a manual low signal line and a low-high signal line and operative in a lower position connecting the source fluid pressure to said lower apply line To engage said lower ratio drive, in a low position connecting the source of fluid pressure to said manual low signal line and in a low-high position connecting the source of fluid pressure to said low-high signal line and in each position exhausting the other of said connected lines; an automatic shift valve having an automatic low signal line and a high ratio line connected to said high friction device and operatively connected to said manual valve and biased to a downshift position connecting said low-high signal line to said automatic low signal line and connected to said governor and operative in response to governor pressure to upshift to an upshift position connecting said low-high signal line to said high ratio line; a shuttle valve having a low ratio line connected to said low ratio device connected to said manual low signal line and said automatic low signal line and operative in response to said manual low signal line pressure to supply fluid pressure to said low ratio line to establish low drive and operative in response to automatic low signal line pressure to supply fluid under pressure to said low ratio line to establish low drive; and inhibitor means connected to said manual valve, said automatic shift valve and said governor operative to permit manual valve shifting between low position and low-high position when the automatic valve is downshifted and inhibiting a manual valve low-high position to low position shift when the automatic valve is upshifted to prevent a manual high to low ratio drive shift above a predetermined speed, and inhibiting a manual valve shift from said low position to said lower position above a predetermined speed.

Claim 13

In a transmission; an input element; an output element; a multi ratio drive gear unit connecting said input element to said output element having a lower, a low and a high fluid actuated friction device respectively providing a lower, a low and a high ratio drive selectively operable for establishing said lower, low and high ratio drives; a source of fluid at a regulated pressure; a governor providing a governor pressure proportional to the speed of one of said elements; a manual valve connected to said source, having a lower apply line connected to said lower fluid actuated friction device, a manual low signal line and a low-high signal line and operative in a lower position connecting the source fluid pressure to said lower apply line To engage said lower ratio drive, in a low position connecting the source of fluid pressure to said manual low signal line and in a low-high position connecting the source of fluid pressure to said low-high signal line and in each position exhausting the other of said connected lines; an automatic shift valve having an automatic low signal line and a high ratio line connected to said high friction device and operatively connected to said manual valve and biased to a downshift position connecting said low-high signal line to said automatic low signal line and connected to said governor and operative in response to governor pressure to upshift to an upshift position connecting said low-high signal line to said high ratio line; a shuttle valve having a low ratio line connected to said low ratio device connected to said manual low signal line and said automatic low signal line and operative in response to said manual low signal line pressure to supply fluid pressure to said low ratio line to establish low drive and operative in response to automatic low signal line pressure to supply fluid under pressure to said low ratio line to establish low drive; and inhibitor means connected to said manual valve, said automatic shift valve and said governor operative to permit manual valve shifting between low position and low-high position when the automatic valve is downshifted and inhibiting a manual valve low-high position to low position shift when the automatic valve is upshifted to prevent a manual high to low ratio drive shift above a predetermined speed, and inhibiting a manual valve shift from said low position to said lower position above a predetermined speed.

Claim 14

The invention defined in claim 8 and said inhibitor means having a cam element variably positioned by said governor and being connected to said low-high signal line of said manual valve and said automatic low signal line of said automatic shift valve and said automatic low signal overcoming said governor and positioning said cam element against a stop member positioned by said low-high signal pressure.