Engagement control of friction drives

Claim 2

An engagement control device for friction drive establishing means comprising a source of fluid pressure in fluid communication with the friction means; and valve means including regulator valve means in fluid communication with said source for controlling fluid pressure in the friction means, movable bias means including slide valve means in fluid communication with said source for maintaining a pressure bias force on said regulator valve means during initial engagement of the friction means, and spool valve means disposed between said regulator valve means and said slide valve means for transmitting the bias force to said regulator valve means and being in fluid communication with said slide valve means for controlling the pressure bias force imposed by said slide valve means during final engagement of the friction means.

Claim 3

An engagement control valve comprising a valve body having a bore therein; regulator valve means slidably disposed in said bore; bias means including plug means slidably disposed in said bore; spool valve means slidably disposed in said bore intermediate said regulator valve means and said plug means; first spring means intermediate said regulator valve means and said spool valve means; second spring means intermediate said plug means and said spool valve means; regulated pressure chamber means adjacent said regulator valve means; bias pressure chamber means adjacent said plug means; exhaust passage means in said valve body circumjacent said spool valve means; and fluid passage means connecting said bias pressure chamber means and said spool valve means and said spool valve means being movable in response to fluid pressure in said regulated pressure chamber to exhaust said bias pressure chamber through said exhaust passage means.

Claim 4

An engagement control valve comprising a valve body having a bore therein; regulator valve means slidably disposed in said bore; bias means including plug means slidably disposed in said bore; spool valve means slidably disposed in said bore intermediate said regulator valve means and said plug means; first spring means intermediate said regulator valve means and said spool valve means; second spring means intermediate said plug means and said spool valve means; regulated pressure chamber means adjacent said regulator valve means; bias pressure chamber means adjacent said plug means; exhaust passage means in said valve body circumjacent said spool valve means; and fluid passage means connecting said bias pressure chamber means and said spool valve means and said spool valve means being movable in response to fluid pressure in said regulated pressure chamber to exhaust said bias pressure chamber through said exhaust passage means.

Claim 5

An engagement control device for a friction drive establishing means comprising a source of fluid pressure in fluid communication with friction means; engagement control valve means including a valve bore, regulator valve means slidably disposed in said bore including restriction means, regulated pressure chamber means in fluid communication wiTh said friction means and said restrictions means, spool valve means slidably disposed in said bore adjacent said regulator valve means, secondary pressure chamber means in fluid communication with said restriction means intermediate said regulator valve means and said spool valve means, first spring means located in said secondary pressure chamber means contacting said regulator valve means and said spool valve means, exhaust chamber means in said valve bore controlled by said spool valve means, pressure bias means slidably disposed in said valve bore, bias chamber means adjacent said bias means in fluid communication with said source for imposing a pressure bias on said regulator valve means, second spring means contacting said bias means and said spool valve means for moving said spool valve means into contact with said regulator valve means and for transmitting the pressure bias thereto; and exhaust passage means in fluid communication with said bias chamber and said spool valve means; said spool valve means being movable in response to fluid pressure in said secondary pressure chamber to permit fluid communication between said exhaust passage means and said exhaust chamber means to exhaust the pressure bias on said regulator valve means.

Claim 6

An engagement control device for a friction drive establishing means comprising a source of fluid pressure in fluid communication with friction means; engagement control valve means including a valve bore, regulator valve means slidably disposed in said bore including restriction means, regulated pressure chamber means in fluid communication wiTh said friction means and said restrictions means, spool valve means slidably disposed in said bore adjacent said regulator valve means, secondary pressure chamber means in fluid communication with said restriction means intermediate said regulator valve means and said spool valve means, first spring means located in said secondary pressure chamber means contacting said regulator valve means and said spool valve means, exhaust chamber means in said valve bore controlled by said spool valve means, pressure bias means slidably disposed in said valve bore, bias chamber means adjacent said bias means in fluid communication with said source for imposing a pressure bias on said regulator valve means, second spring means contacting said bias means and said spool valve means for moving said spool valve means into contact with said regulator valve means and for transmitting the pressure bias thereto; and exhaust passage means in fluid communication with said bias chamber and said spool valve means; said spool valve means being movable in response to fluid pressure in said secondary pressure chamber to permit fluid communication between said exhaust passage means and said exhaust chamber means to exhaust the pressure bias on said regulator valve means.

Claim 7

An engagement control valve for controlling fluid pressure supplied by a fluid source to a friction drive establishing means comprising; regulator valve means for controlling the pressure increase in said friction means at one rate during an initial phase of engagement, second rate during an intermediate phase of engagement, and at a third rate during a final phase of engagement, pressure bias means in fluid communication with the source for imposing a pressure bias on said regulator valve means during the initial phase, spool valve means and restriction means for controlling the pressure bias during the intermediate phase, and exhausting the pressure bias during the final phase.

Claim 8

An engagement control valve for controlling fluid pressure supplied by a fluid source to a friction drive establishing means comprising; regulator valve means for controlling the pressure increase in said friction means at one rate during an initial phase of engagement, second rate during an intermediate phase of engagement, and at a third rate during a final phase of engagement, pressure bias means in fluid communication with the source for imposing a pressure bias on said regulator valve means during the initial phase, spool valve means and restriction means for controlling the pressure bias during the intermediate phase, and exhausting the pressure bias during the final phase.

Claim 9

An engagement control valve for controlling fluid pressure supplied by a fluid source to a friction drive establishing means comprising regulator valve means for controlling the pressure increase in the friction means at one rate during an initial phase of engagement, at a second rate during an intermediate phase of engagement, and at a third rate during a final phase of engagement, pressure abutment means, bias means operatively connected to said pressure abutment means, spool valve means operatively connected to said bias means and said regulator valve means, first flow control means on said regulator valve means for controlling said first rate and said third rate, and second flow control means operatively connected with and controlled by said spool valve means and cooperating with said first flow control means for controlling said second rate.

Claim 10

An engagement control valve for controlling fluid pressure supplied by a fluid source to a friction drive establishing means comprising regulator valve means for controlling the pressure increase in the friction means at one rate during an initial phase of engagement, at a second rate during an intermediate phase of engagement, and at a third rate during a final phase of engagement, pressure abutment means, bias means operatively connected to said pressure abutment means, spool valve means operatively connected to said bias means and said regulator valve means, first flow control means on said regulator valve means for controlling said first rate and said third rate, and second flow control means operatively connected with and controlled by said spool valve means and cooperating with said first flow control means for controlling said second rate.

Claim 11

An engagement control device for friction drive establishing means having relatively rotatable members which have a slip speed during engagement and rotate in unison at full engagement said control comprising a source of fluid pressure in fluid communication with the friction means for engaging the friction means and valve means including regulator valve means in fluid communication with said source for controlling the engagement pressure in the friction means, movable bias means including slide valve means in fluid communication with said source for maintaining a pressure bias force on said regulator valve means during engagement of the friction means, and control valve means operatively connected in fluid communication with said slide valve means for controlling the pressure bias force imposed by said slide valve means during engagement of the friction means to decrease the engagement pressure as the slip speed approaches zero.

Claim 12

An engagement control device for friction drive establishing means having relatively rotatable members which have a slip speed during engagement and rotate in unison at full engagement said control comprising a source of fluid pressure in fluid communication with the friction means for engaging the friction means and valve means including regulator valve means in fluid communication with said source for controlling the engagement pressure in the friction means, movable bias means including slide valve means in fluid communication with said source for maintaining a pressure bias force on said regulator valve means during engagement of the friction means, and control valve means operatively connected in fluid communication with said slide valve means for controlling the pressure bias force imposed by said slide valve means during engagement of the friction means to decrease the engagement pressure as the slip speed approaches zero.

Claim 13

An engagement control device for friction drive establishing means comprising a source of fluid pressure selectively in fluid communication with the friction means; input governor means for providing a governor pressure signal; regulator valve means in fluid comMunication with said friction means for controlling the fluid pressure therein; moveable bias means operatively connected with said regulator valve means and being responsive to a bias pressure for maintaining a bias on said regulator valve means, and control means including a slide valve responsive to the governor pressure signal for controlling the bias pressure on said bias means.

Claim 14

An engagement control device for friction drive establishing means comprising a source of fluid pressure selectively in fluid communication with the friction means; input governor means for providing a governor pressure signal; regulator valve means in fluid comMunication with said friction means for controlling the fluid pressure therein; moveable bias means operatively connected with said regulator valve means and being responsive to a bias pressure for maintaining a bias on said regulator valve means, and control means including a slide valve responsive to the governor pressure signal for controlling the bias pressure on said bias means.

Claim 15

An engagement controlled friction drive comprising fluid pressure operated friction drive establishing means having a slip speed characteristic during engagement that is reduced to zero when the friction drive establishing means is engaged and a coefficient of friction characteristic that increases as the slip speed approaches zero; and engagement control means for controlling the fluid pressure in said friction drive establishing means to reduce the fluid pressure when the slip speed approaches zero and the coefficient of friction increases and to increase the fluid pressure when the slip speed is zero.

Claim 16

An engagement controlled friction drive comprising fluid pressure operated friction drive establishing means having a slip speed characteristic during engagement that is reduced to zero when the friction drive establishing means is engaged and a coefficient of friction characteristic that increases as the slip speed approaches zero; and engagement control means for controlling the fluid pressure in said friction drive establishing means to reduce the fluid pressure when the slip speed approaches zero and the coefficient of friction increases and to increase the fluid pressure when the slip speed is zero.