Transmission shift control

Claim 2

A TRANSMISSION; MULTIRATIO GEAR MEANS HAVING AN INPUT, OUTPUT, LOW DRIVE FLUID OPERATED MEANS FOR ESTABLISHING A LOW RATIO DRIVE BETWEEN SAID INPUT AND OUTPUT AND HIGH DRIVE FLUID OPERATED MEANS FOR ESTABLISHING A HIGH RATIO DRIVE BETWEEN SAID INPUT AND OUTPUT; A SOURCE OF FLUID UNDER PRESSURE; GOVERNOR MEANS CONNECTED TO SAID SOURCE AND SAID OUTPUT PROVIDING A GOVERNOR PRESSURE VARYING WITH OUTPUT SPEED; TORQUE DEMAND MEANS RESPONSIVE TO ENGINE TORQUE DEMAND PROVIDING A TORQUE DEMAND SIGNAL VARYING WITH TORQUE DEMAND; SHIFT CONTROL MEANS INCLUDING A BORE AND SHIFT VALVE MEANS MOVABLE IN SAID BORE CONNECTED TO SAID SOURCE, SAID LOW AND HIGH DRIVE MEANS, SAID GOVERNOR MEANS AND SAID TORQUE DEMAND MEANS, OPERATIVE IN A DOWNSHIFT POSITION TO CONNECT SAID SOURCE TO SAID LOW DRIVE FLUID OPERATED MEANS, OPERATIVE IN AN UPSHIFT POSITION TO CONNECT SAID SOURCE TO SAID HIGH DRIVE FLUID OPERATED MEANS AND BIASED IN AN UPSHIFT DIRECTION BY SAID GOVERNOR SIGNAL AND HAVING TORQUE DEMAND BIASING MEANS MOVABLE IN SAID BORE CONNECTED TO SAID TORQUE DEMAND MEANS AND RESPONSIVE TO SAID TORQUE DEMAND SIGNAL OPERATIVE IN A DOWNSHIFT POSITION TO ENGAGE AND PROVIDE AN UPSHIFT RESISTING BIAS TO SAID DOWNSHIFTED SHIFT VALVE MEANS AND IN AN UPSHIFT POSITION TO ENGAGE AND PROVIDE A DOWNSHIFT BIAS TO SAID UPSHIFTED SHIFT VALVE MEANS FOR AUTOMATIC SHIFTING AT INCREASING AND HIGHER UPSHIFT SPEEDS AND LOWER DOWNSHIFT SPEEDS WITH INCREASING TORQUE DEMAND, SAID SHIFT VALVE MEANS AND SAID BIASING MEANS HAVING ENGAGING END PORTIONS WITHIN SAID BORE; AND MANUAL DOWNSHIFT MEANS HAVING DOWNSHIFT AREA MEANS ON SAID ENGAGING END PORTIONS AND MANUAL DOWNSHIFT FLUID SUPPLY MEANS SELECTIVELY MANUALLY CONTROLLED TO SUPPLY DOWNSHIFT PRESSURE TO SAID BORE TO ACT ON SAID DOWNSHIFT AREA MEANS OF SAID BIASING MEANS TO HOLD SAID BIASING MEANS IN SAID UPSHIFT POSITION, TO ACT ON ONE AREA SAID DOWNSHIFT AREA MEANS OF SAID SHIFT VALVE MEANS WHEN SAID SHIFT VALVE MEANS IS UPSHIFTED TO DOWNSHIFT SAID SHIFT VALVE MEANS AT A HIGHER SPEED THAN SAID AUTOMATIC DOWNSHIFT, AND TO ACT ON SAID DOWNSHIFT AREA MEANS OF SAID SHIFT VALVE MEANS WHEN SAID SHIFT VALVE MEANS IS DOWNSHIFTED TO PREVENT AN UPSHIFT UNTIL A SPEED SUBSTANTIALLY HIGHER THAN SAID MANUAL DOWNSHIFT SPEED.

Claim 3

a transmission; multiratio gear means having an input, output, low drive fluid operated means for establishing a low ratio drive between said input and output and high drive fluid operated means for establishing a high ratio drive between said input and output; a source of fluid under pressure; governor means connected to said source and said output providing a governor pressure varying with output speed; torque demand means responsive to engine torque demand providing a torque demand signal varying with torque demand; shift control means including a bore and shift valve means movable in said bore connected to said source, said low and high drive means, said governor means and said torque demand means, operative in a downshift position to connect said source to said low drive fluid operated means, operative in an upshift position to connect said source to said high drive fluid operated means and biased in an upshift direction by said governor signal and having torque demand biasing means movable in said bore connected to said torque demand means and responsive to said torque demand signal operative in a downshift position to engage and provide an upshift resisting bias to said downshifted shift valve means and in an upshift position to engage and provide a downshift bias to said upshifted shift valve means for automatic shifting at increasing and higher upshift speeds and lower downshift speeds with increasing torque demand, said shift valve means and said biasing means having engaging end portions within said bore; and manual downshift means having downshift area means on said engaging end portions and manual downshift fluid supply means selectively manually controlled to supply downshift pressure to said bore to act on said downshift area means of said biasing means to hold said biasing means in said upshift position, to act on one area said downshift area means of said shift valve means when said shift valve means is upshifted to downshift said shift valve means at a higher speed than said automatic downshift, and to act on said downshift area means of said shift valve means when said shift valve means is downshifted to prevent an upshift until a speed substantially higher than said manual downshift speed.

Claim 4

a transmission; multiratio gear means having an input, output, low drive fluid operated means for establishing a low ratio drive between said input and output and high drive fluid operated means for establishing a high ratio drive between said input and output; a source of fluid under pressure; governor means connected to said source and said output providing a governor pressure varying with output speed; torque demand means responsive to engine torque demand providing a torque demand signal varying with torque demand; shift control means including a bore and shift valve means movable in said bore connected to said source, said low and high drive means, said governor means and said torque demand means, operative in a downshift position to connect said source to said low drive fluid operated means, operative in an upshift position to connect said source to said high drive fluid operated means and biased in an upshift direction by said governor signal and having torque demand biasing means movable in said bore connected to said torque demand means and responsive to said torque demand signal operative in a downshift position to engage and provide an upshift resisting bias to said downshifted shift valve means and in an upshift position to engage and provide a downshift bias to said upshifted shift valve means for automatic shifting at increasing and higher upshift speeds and lower downshift speeds with increasing torque demand, said shift valve means and said biasing means having engaging end portions within said bore; and manual downshift means having downshift area means on said engaging end portions and manual downshift fluid supply means selectively manually controlled to supply downshift pressure to said bore to act on said downshift area means of said biasing means to hold said biasing means in said upshift position, to act on one area said downshift area means of said shift valve means when said shift valve means is upshifted to downshift said shift valve means at a higher speed than said automatic downshift, and to act on said downshift area means of said shift valve means when said shift valve means is downshifted to prevent an upshift until a speed substantially higher than said manual downshift speed.

Claim 5

The invention defined in claim 1 and said downshift area means having a full flow passage and a first area means on said shift valve means supplied with downshift pressure when the shift valve is downshifted and upshifted to provide a downshift bias, second area means, a restricted exhaust from said second area means, a less restricted connection from said first area means to said second area means when said shift valve means is downshifted to provide high pressure in said second area means and a more restricted connection from said first area means to said second area means when said shift valve means is upshifted to provide reduced pressure in said second area means.

Claim 6

The invention defined in claim 1 and said downshift area means including seal means on said end portions forming between the end portions a small area chamber when they are engaged and a large area chamber when they are spaced from each other; said downshift fluid supply being connected to said small area chamber in all positions of said shift valve means and said biasing means to position said biasing means in upshsift position and when said shift valve means is upshifted to act in said small area chamber for downshift at upshift downshift speed and when saId shift valve means is downshifted to act in said large area chamber to prevent an upshift up to a substantially higher speed.

Claim 7

The invention defined in claim 1 and said downshift area means including an annular seal means on said end portions forming between both end portions when they are engaged an outer area annular chamber and an inner area chamber and when they are spaced from each other a combined area chamber; said downshift fluid supply being connected to said outer chamber in the downshift and upshift positions of said shift valve means and said biasing means operative to position said biasing means in upshift position and when the shift valve means is upshifted to act in said outer area chamber to downshift said shift valve means at downshift speed and when said shift valve means is downshifted to act in both chambers to prevent and upshift up to a substantially higher speed.

Claim 8

The invention defined in claim 4 and a restricted exhaust passage connecting said inner area chamber to exhaust; said annular seal providing at least a more restricted flow passage when said shift valve means is upshifted operative on the supply of downshift fluid to pressurize said outer chamber and exhaust said inner passage and when said shift valve means is downshifted said annular seal providing a less restricted passage than said exhaust passage to pressurize both chambers.

Claim 9

The invention defined in claim 4 and said annular seal means being a sliding seal between a piston on one end portion and a cylinder on the other end portion.

Claim 10

The invention defined in claim 4 and said annular seal means being an annular face seal on said end portions.

Claim 11

In a transmission; multiratio gear means having an input, output, low drive fluid operated means for establishing a low ratio drive between said input and output and high drive fluid operated means for establishing a high ratio drive between said input and output; a source of fluid under pressure; governor means connected to said source and said output providing a governor pressure varying with output speed; torque demand means responsive to engine torque demand providing a torque demand signal varying with torque demand; shift control means including shift valve means connected to said source, said low and high drive means, said governor means and said torque demand means, operative in a downshift position to connect said source to said low drive fluid operated means operative in an upshift position to connect said source to said high drive fluid operated means and biased in an upshift direction by said governor signal and in a downshift direction by said torque demand signal at a high value when downshifted and a lower value when upshifted to provide an upshift to provide automatic shifting at increasing and higher upshift speeds and lower downshift speeds, and manual downshift means having manual downshift fluid supply means selectively manually controlled to supply downshift pressure, first downshift chamber means having a first area operatively connected to said shift valve means operative in response to said downshift pressure on said first area when said shift valve means is upshifted to downshift said shift valve means at a higher speed than said automatic downshift, second downshift chamber means having a second area operatively connected to said shift valve means operative in response to said downshift pressure on said first and second areas when said shift valve means is downshifted to prevent an upshift until a speed substantially higher than said manual downshift speed, restricted exhaust means connecting said second downshift chamber means to exhaust in the upshift position and the downshift position of said shift valve means and variable restricted supply means connected to said manual downshift fluid supply means and said first and second chamber means operative when said shift valve means is in an upshift position to connect said manual downshift fluid supply means to said first chamber means so downShift pressure acts in said first chamber means on said first area for a downshift and through a restriction smaller than said exhaust restriction to said second chamber means so downshift pressure does not act in said second chamber means on said second area and when said shift valve means is in a downshift position to connect said manual downshift fluid supply means to said first chamber to act on said first area and through a passage larger than said exhaust restriction so downshift pressure does act in said second chamber means on said second area to act on both areas to hold said shift valve means upshifted until a speed substantially higher than said manual downshift speed.

Claim 12

In a transmission; multiratio gear means having an input, output, low drive fluid operated means for establishing a low ratio drive between said input and output and high drive fluid operated means for establishing a high ratio drive between said input and output; a source of fluid under pressure; governor means connected to said source and said output providing a governor pressure varying with output speed; torque demand means responsive to engine torque demand providing a torque demand signal varying with torque demand; shift control means including shift valve means connected to said source, said low and high drive means, said governor means and said torque demand means, operative in a downshift position to connect said source to said low drive fluid operated means operative in an upshift position to connect said source to said high drive fluid operated means and biased in an upshift direction by said governor signal and in a downshift direction by said torque demand signal at a high value when downshifted and a lower value when upshifted to provide an upshift to provide automatic shifting at increasing and higher upshift speeds and lower downshift speeds, and manual downshift means having manual downshift fluid supply means selectively manually controlled to supply downshift pressure, first downshift chamber means having a first area operatively connected to said shift valve means operative in response to said downshift pressure on said first area when said shift valve means is upshifted to downshift said shift valve means at a higher speed than said automatic downshift, second downshift chamber means having a second area operatively connected to said shift valve means operative in response to said downshift pressure on said first and second areas when said shift valve means is downshifted to prevent an upshift until a speed substantially higher than said manual downshift speed, restricted exhaust means connecting said second downshift chamber means to exhaust in the upshift position and the downshift position of said shift valve means and variable restricted supply means connected to said manual downshift fluid supply means and said first and second chamber means operative when said shift valve means is in an upshift position to connect said manual downshift fluid supply means to said first chamber means so downShift pressure acts in said first chamber means on said first area for a downshift and through a restriction smaller than said exhaust restriction to said second chamber means so downshift pressure does not act in said second chamber means on said second area and when said shift valve means is in a downshift position to connect said manual downshift fluid supply means to said first chamber to act on said first area and through a passage larger than said exhaust restriction so downshift pressure does act in said second chamber means on said second area to act on both areas to hold said shift valve means upshifted until a speed substantially higher than said manual downshift speed.

Claim 13

In a transmission; multiratio gear means having an input, output, low drive fluid operated means for establishing a low ratio drive between said input and output and high drive fluid operated means for establishing a high ratio drive between said input and output; a source of fluid under pressure; governor means connected to said source and said output providing a governor pressure varying with output speed; torque demand means responsive to engine torque demand providing a torque demand signal varying with torque demand; shift control means including shift valve means connected to said source, said low and high drive means and said governor means, having an end portion, operative in a downshift position to connect said source to said low drive fluid operated means, biased in an upshift direction by said governor signal and operative in an upshift position to connect said source to said high drive fluid operated means and providing a small automatic shift hysteresis, control valve biasing means having an end portion engaging said end portion of said shift valve means continuously during automatic shifting to transmit a bias, connected to said torque demand means for control by said torque demand means to provide a torque demand bias opposing said governor bias and manual downshift means having a cylinder in said end portion of said shift valve means and a piston on said end portion of said control valve biasing means fitting into said cylinder forming a chamber, restricted exhaust means continuously connecting said chamber to exhaust, said piston and cylinder having restriction means providing a smaller restricted flow passage than said restricted exhaust passage for flow to said chamber when said shift valve means and said control biasing means are both upshifted and a larger flow passage than said restricted exhaust passage for flow to said chamber when said control biasing valve means is upshifted and said shift valve means is downshifted, said end portion of said shift valve means having a first external area upstream of said smaller restriction and a second area in said chamber and manual supply means connected to said source and said manual downshift means operative to position said biasing control means in the upshift position, when said shift valve means is in the upshift position to supply a regulated manual fluid pressure to act on said first external area, flow through said smaller restriction to said chamber and to said restricted exhaust to provide not more than a very small pressure acting on said second area to provide a downshift at an output speed to a lower ratio drive in which the input speed is the maximum power speed of the engine and operative after a downshift of said shift valve means to act on said first area flow through said larger flow passage to said chamber and to said restricted exhaust to provide said regulated manual fluid pressure in said chamber acting on said second area to act on both areas to hold said shift valve means downshifted up to the maximum operative engine braking engine speed.

Claim 14

In a transmission; multiratio gear means having an input, output, low drive fluid operated means for establishing a low ratio drive between said input and output and high drive fluid operated means for establishing a high ratio drive between said input and output; a source of fluid under pressure; governor means connected to said source and said output providing a governor pressure varying with output speed; torque demand means responsive to engine torque demand providing a torque demand signal varying with torque demand; shift control means including shift valve means connected to said source, said low and high drive means and said governor means, having an end portion, operative in a downshift position to connect said source to said low drive fluid operated means, biased in an upshift direction by said governor signal and operative in an upshift position to connect said source to said high drive fluid operated means and providing a small automatic shift hysteresis, control valve biasing means having an end portion engaging said end portion of said shift valve means continuously during automatic shifting to transmit a bias, connected to said torque demand means for control by said torque demand means to provide a torque demand bias opposing said governor bias and manual downshift means having a cylinder in said end portion of said shift valve means and a piston on said end portion of said control valve biasing means fitting into said cylinder forming a chamber, restricted exhaust means continuously connecting said chamber to exhaust, said piston and cylinder having restriction means providing a smaller restricted flow passage than said restricted exhaust passage for flow to said chamber when said shift valve means and said control biasing means are both upshifted and a larger flow passage than said restricted exhaust passage for flow to said chamber when said control biasing valve means is upshifted and said shift valve means is downshifted, said end portion of said shift valve means having a first external area upstream of said smaller restriction and a second area in said chamber and manual supply means connected to said source and said manual downshift means operative to position said biasing control means in the upshift position, when said shift valve means is in the upshift position to supply a regulated manual fluid pressure to act on said first external area, flow through said smaller restriction to said chamber and to said restricted exhaust to provide not more than a very small pressure acting on said second area to provide a downshift at an output speed to a lower ratio drive in which the input speed is the maximum power speed of the engine and operative after a downshift of said shift valve means to act on said first area flow through said larger flow passage to said chamber and to said restricted exhaust to provide said regulated manual fluid pressure in said chamber acting on said second area to act on both areas to hold said shift valve means downshifted up to the maximum operative engine braking engine speed.

Claim 15

In a transmission; multiratio gear means having an input, output, low drive fluid operated means for establishing a low ratio drive between said input and output and high drive fluid operated means for establishing a high ratio drive between said input and output; a source of fluid under pressure; governor means connected to said source and said output providing a governor pressure varying directly with output speed; torque demand means responsive to engine torque demand providing a torque demand signal varying inversely with torque demand; shift control means includin g shift valve means connected to said source, said low and high drive means and said governor means having an end portion and operative in a downshift position to connect said source to said low drive fluid operated means, biased in an upshift direction by said governor signal and operative in an upshift position to connect said source to said high drive fluid operated means and providing a small automatic shift hysteresis, biasing control means having an end portion engaging said end portion of said shift valve means continuously during automatic shifting to transmit a bias, connected to said torque demand means for control by said torque demand means to provide an upshift opposing bias increasing at a low rate with torque demand and a downshifting bias increasing at a higher rate to the same value to bias said shift valve means in a downshift direction to provide automatic shifting in which the upshift and downshift speeds both increase and converge and are separated only by said small automatic shift hysteresis at full throttle and manual downshift means having a cylinder in said end portion of said shift valve means and a piston on said end portion of said control biasing means fitting into said cylinder forming a chamber, restricted exhaust means continuously connecting said chamber to exhaust, said piston and cylinder having restriction means providing a smaller restricted flow passage than said restricted exhaust passage for flow to said chamber when said shift valve means and said control biasing means are both upshifted and a larger flow passage than said restricted exhaust passage for flow to said chamber when said control biasing valve means is upshifted and said shift valve means is downshifted, said end portion of said shift valve means having a first external area upstream of said smaller restriction and a second area in said chamber and manual supply means connected to said source and said manual downshift means operative to position said biasing control means in the upshift position, when said shift valve means is in the upshift position to supply a regulated manual fluid pressure to act on said first external area, flow through said smaller restriction to said chamber and to said restricted exhaust to provide not more than a very small pressure acting on said second area to provide a downshift at an output speed to a lower ratio drive in which the input speed is the maximum power speed of the engine and operative after a downshift of said shift valve means to act on said first area flow through said larger flow passage to said chamber and to said restricted exhaust to provide said regulated manual fluid pressure in said chamber acting on said second area to hold said shift valve means downshifted up to the maximum operative engine braking engine speed.

Claim 16

In a transmission; multiratio gear means having an input, output, low drive fluid operated means for establishing a low ratio drive between said input and output and high drive fluid operated means for establishing a high ratio drive between said input and output; a source of fluid under pressure; governor means connected to said source and said output providing a governor pressure varying directly with output speed; torque demand means responsive to engine torque demand providing a torque demand signal varying inversely with torque demand; shift control means includin g shift valve means connected to said source, said low and high drive means and said governor means having an end portion and operative in a downshift position to connect said source to said low drive fluid operated means, biased in an upshift direction by said governor signal and operative in an upshift position to connect said source to said high drive fluid operated means and providing a small automatic shift hysteresis, biasing control means having an end portion engaging said end portion of said shift valve means continuously during automatic shifting to transmit a bias, connected to said torque demand means for control by said torque demand means to provide an upshift opposing bias increasing at a low rate with torque demand and a downshifting bias increasing at a higher rate to the same value to bias said shift valve means in a downshift direction to provide automatic shifting in which the upshift and downshift speeds both increase and converge and are separated only by said small automatic shift hysteresis at full throttle and manual downshift means having a cylinder in said end portion of said shift valve means and a piston on said end portion of said control biasing means fitting into said cylinder forming a chamber, restricted exhaust means continuously connecting said chamber to exhaust, said piston and cylinder having restriction means providing a smaller restricted flow passage than said restricted exhaust passage for flow to said chamber when said shift valve means and said control biasing means are both upshifted and a larger flow passage than said restricted exhaust passage for flow to said chamber when said control biasing valve means is upshifted and said shift valve means is downshifted, said end portion of said shift valve means having a first external area upstream of said smaller restriction and a second area in said chamber and manual supply means connected to said source and said manual downshift means operative to position said biasing control means in the upshift position, when said shift valve means is in the upshift position to supply a regulated manual fluid pressure to act on said first external area, flow through said smaller restriction to said chamber and to said restricted exhaust to provide not more than a very small pressure acting on said second area to provide a downshift at an output speed to a lower ratio drive in which the input speed is the maximum power speed of the engine and operative after a downshift of said shift valve means to act on said first area flow through said larger flow passage to said chamber and to said restricted exhaust to provide said regulated manual fluid pressure in said chamber acting on said second area to hold said shift valve means downshifted up to the maximum operative engine braking engine speed.

Claim 17

In a transmission; multiratio gear means having an input, an output and fluid operated means for selectively establishing a low ratio drive and a high ratio drive; source means providing fluid under pressure; governor means connected to said gear means providing a governor signal varying with speed; torque demand signal means responsive to engine torque demand providing a torque demand signal varying with torque demand; shift control means operatively connected to said source means, said governor means, said torque demand signal means and said fluid operated means controlled by said governor signal and torque demand signal for automatic upshifting at higher speeds with increasing torque demand to upshift position and downshifting at lower speeds to downshift position and operative to control the supply of fluid between said source and said fluid operated means to establish said low ratio drive in downshift positiOn and said high ratio drive in upshift position; said shift control means including a shift valve assembly having a bore, a shift valve element and a control valve element both slidable in said bore between upshift and downshift position and each having an adjacent end portion, governor bias means responsive to said governor signal to bias said shift valve element to upshift position, torque demand biasing means responsive to said torque demand signal biasing said control valve element to downshift position and to continuously engage said adjacent end portions for movement of said valve elements as a unit during said automatic shifting; manual downshift signal means manually selectively providing a fluid pressure manual downshift signal to said bore between said adjacent end portions in all positions of said valve elements; and downshift area means having a control portion on each adjacent end portion located within said bore and cooperating only with each other for operation responsive to said downshift signal in said bore to position said control valve element in upshift position and provide a large area exposed to said downshift signal for a large downshift bias when said shift valve element is in said downshift position and a small area exposed to said downshift signal for a small downshift bias when said shift valve element is in said upshift position to provide manual shift hysteresis by manual downshift signal pressure for upshifts up to a predetermined speed and downshifts at a lower speed.

Claim 18

In a transmission; multiratio gear means having an input, an output and fluid operated means for selectively establishing a low ratio drive and a high ratio drive; source means providing fluid under pressure; governor means connected to said gear means providing a governor signal varying with speed; torque demand signal means responsive to engine torque demand providing a torque demand signal varying with torque demand; shift control means operatively connected to said source means, said governor means, said torque demand signal means and said fluid operated means controlled by said governor signal and torque demand signal for automatic upshifting at higher speeds with increasing torque demand to upshift position and downshifting at lower speeds to downshift position and operative to control the supply of fluid between said source and said fluid operated means to establish said low ratio drive in downshift positiOn and said high ratio drive in upshift position; said shift control means including a shift valve assembly having a bore, a shift valve element and a control valve element both slidable in said bore between upshift and downshift position and each having an adjacent end portion, governor bias means responsive to said governor signal to bias said shift valve element to upshift position, torque demand biasing means responsive to said torque demand signal biasing said control valve element to downshift position and to continuously engage said adjacent end portions for movement of said valve elements as a unit during said automatic shifting; manual downshift signal means manually selectively providing a fluid pressure manual downshift signal to said bore between said adjacent end portions in all positions of said valve elements; and downshift area means having a control portion on each adjacent end portion located within said bore and cooperating only with each other for operation responsive to said downshift signal in said bore to position said control valve element in upshift position and provide a large area exposed to said downshift signal for a large downshift bias when said shift valve element is in said downshift position and a small area exposed to said downshift signal for a small downshift bias when said shift valve element is in said upshift position to provide manual shift hysteresis by manual downshift signal pressure for upshifts up to a predetermined speed and downshifts at a lower speed.

Claim 19

In a transmission; multiratio gear means having an input, an output and fluid operated means for selectively establishing a low ratio drive and a high ratio drive; source means providing fluid under pressure; governor means connected to said gear means providing a governor signal varying with speed; torque demand signal means responsive to engine torque demand providing a torque demand signal varying with torque demand; shift control means operatively connected to said source means, said governor means, said torque demand signal means and said fluid operated means controlled by said governor signal and torque demand signal for automatic upshifting at higher speeds with increasing torque demand to upshift position and downshifting at lower speeds to downshift position and operative to control the supply of fluid between said source and said fluid operated means to establish said low ratio drive in downshift position and said high ratio drive in upshift position; said shift control means including a shift valve assembly having a bore, a shift valve element and a control valve element both slidable in said bore between upshift and downshift position and each having an adjacent end portion, governor bias means responsive to said governor signal to bias said shift valve element to upshift position, torque demand biasing means responsive to said torque demand signal biasing said control valve element to downshift position and to continuously engage said adjacent end portions for movement of said valve elements as a unit during said automatic shifting; manual downshift signal means manually selectively providing a manual downshift fluid pressure to said bore between said adjacent end portions in all positions of said valve elements; and downshift means having controlled area means on said adjacent end portion of said shift valve element and area control means on said adjacent end portion of said control valve element cooperating with only each other and operative in response to said downshift pressure in said bore to position said control valve element in said upshift position to provide when said shift valve element is in upshift position a small area of said controlled area means exposed to downshift pressure in said bore between said valve elements for a small downshift bias and to provide when said shift valve element is in downshift position a larger area of said controlled area means exposed to downshift pressure in said bore for a large downshift bias to provide manual shift hysTeresis by manual downshift pressure for upshifts at high speed and downshifts at a lower speed.

Claim 20

In a transmission; multiratio gear means having an input, an output and fluid operated means for selectively establishing a low ratio drive and a high ratio drive; source means providing fluid under pressure; governor means connected to said gear means providing a governor signal varying with speed; torque demand signal means responsive to engine torque demand providing a torque demand signal varying with torque demand; shift control means operatively connected to said source means, said governor means, said torque demand signal means and said fluid operated means controlled by said governor signal and torque demand signal for automatic upshifting at higher speeds with increasing torque demand to upshift position and downshifting at lower speeds to downshift position and operative to control the supply of fluid between said source and said fluid operated means to establish said low ratio drive in downshift position and said high ratio drive in upshift position; said shift control means including a shift valve assembly having a bore, a shift valve element and a control valve element both slidable in said bore between upshift and downshift position and each having an adjacent end portion, governor bias means responsive to said governor signal to bias said shift valve element to upshift position, torque demand biasing means responsive to said torque demand signal biasing said control valve element to downshift position and to continuously engage said adjacent end portions for movement of said valve elements as a unit during said automatic shifting; manual downshift signal means manually selectively providing a manual downshift fluid pressure to said bore between said adjacent end portions in all positions of said valve elements; and downshift means having controlled area means on said adjacent end portion of said shift valve element and area control means on said adjacent end portion of said control valve element cooperating with only each other and operative in response to said downshift pressure in said bore to position said control valve element in said upshift position to provide when said shift valve element is in upshift position a small area of said controlled area means exposed to downshift pressure in said bore between said valve elements for a small downshift bias and to provide when said shift valve element is in downshift position a larger area of said controlled area means exposed to downshift pressure in said bore for a large downshift bias to provide manual shift hysTeresis by manual downshift pressure for upshifts at high speed and downshifts at a lower speed.

Claim 21

In a transmission; multiratio gear means having an input, an output and fluid operated means for selectively establishing a low ratio drive and a high ratio drive; source means providing fluid under pressure; governor means connected to said gear means providing a governor signal varying with speed; torque demand signal means responsive to engine torque demand providing a torque demand signal varying with torque demand; shift control means operatively connected to said source means, said governor means, said torque demand signal means and said fluid operated means controlled by said governor signal and torque demand signal for automatic upshifting at higher speeds with increasing torque demand to upshift position and downshifting at lower speeds to downshift position and operative to control the supply of fluid between said source and said fluid operated means to establish said low ratio drive in downshift position and said high ratio drive in upshift position; said shift control means including a shift valve assembly having a bore, a shift valve element and a control valve element both slidable in said bore between upshift and downshift position and each having an adjacent end portion, governor bias means responsive to said governor signal to bias said shift valve element to upshift position, torque demand biasing means responsive to said torque demand signal biasing said control valve element to downshift position and to continuously engage said adjacent end portions for movement of said valve elements as a unit during said automatic shifting; manual downshift signal means manually selectively providing a manual downshift fluid pressure to said bore between said adjacent end portions in all positions of said valve elements; and downshift means having controlled area means with a first area means exposed to pressure in said bore at all times and a second area means on said adjacent end portion of said shift valve element, area control means with a third area means on said adjacent end portion of said control valve element, a restricted exhaust from said second area means, restriction means for flow from said first area means to said second area means having a more restricted passage than said restricted exhaust when said shift valve is upshifted and a less restricted passage than said restricted exhaust when said shift valve is downshifted and operative in response to said downshift pressure in said bore acting on said third area means to position said control valve element in said upshift position to provide when said shift valve element is in upshift position downshift pressure acting on said first area means, flowing through said more restricted passage over said second area means and to said restricted exhaust to provide not more than a low pressure acting on said second area means for a small downshift bias and to provide when said shift valve element is in downshift position downshift pressure acting on said first area means and flowing through less restricted passage, over said second area means and to said restricted exhaust to provide downshift pressure on said second area means for a large downshift bias to provide manual hysteresis by manual downshift pressure for upshifts at high speed and downshifts at a lower speed.

Claim 22

In a transmission; multiratio gear means having an input, an output and fluid operated means for selectively establishing a low ratio drive and a high ratio drive; source means providing fluid under pressure; governor means connected to said gear means providing a governor signal varying with speed; torque demand signal means responsive to engine torque demand providing a torque demand signal varying with torque demand; shift control means operatively connected to said source means, said governor means, said torque demand signal means and said fluid operated means controlled by said governor signal and torque demand signal for automatic upshifting at higher speeds with increasing torque demand to upshift position and downshifting at lower speeds to downshift position and operative to control the supply of fluid between said source and said fluid operated means to establish said low ratio drive in downshift position and said high ratio drive in upshift position; said shift control means including a shift valve assembly having a bore, a shift valve element and a control valve element both slidable in said bore between upshift and downshift position and each having an adjacent end portion, governor bias means responsive to said governor signal to bias said shift valve element to upshift position, torque demand biasing means responsive to said torque demand signal biasing said control valve element to downshift position and to continuously engage said adjacent end portions for movement of said valve elements as a unit during said automatic shifting; manual downshift signal means manually selectively providing a manual downshift fluid pressure to said bore between said adjacent end portions in all positions of said valve elements; and downshift means having controlled area means with a first area means exposed to pressure in said bore at all times and a second area means on said adjacent end portion of said shift valve element, area control means with a third area means on said adjacent end portion of said control valve element, a restricted exhaust from said second area means, restriction means for flow from said first area means to said second area means having a more restricted passage than said restricted exhaust when said shift valve is upshifted and a less restricted passage than said restricted exhaust when said shift valve is downshifted and operative in response to said downshift pressure in said bore acting on said third area means to position said control valve element in said upshift position to provide when said shift valve element is in upshift position downshift pressure acting on said first area means, flowing through said more restricted passage over said second area means and to said restricted exhaust to provide not more than a low pressure acting on said second area means for a small downshift bias and to provide when said shift valve element is in downshift position downshift pressure acting on said first area means and flowing through less restricted passage, over said second area means and to said restricted exhaust to provide downshift pressure on said second area means for a large downshift bias to provide manual hysteresis by manual downshift pressure for upshifts at high speed and downshifts at a lower speed.