Flow control arrangement for a piston pump

Claim 2

Flow control arrangement for a piston pump, comprising a stator having inlet means and high pressure outlet means, and including actuator means, said inlet means including an inlet duct in said stator, and a biassed throttle valve in said inlet duct, and said outlet means including an oulet duct in said stator, said stator being formed with a connecting duct connecting said outlet duct with said throttle valve for operating the same to reduce the inlet flow of fluid; a biassed outlet check valve in said connecting duct in the region of said outlet duct, and opening when the pressure in said outlet duct is too high so that pressure fluid flows through said outlet check valve and connecting duct to said throttle valve for reducing the flow cross section of said inlet duct; a rotor including a rotary cylinder block having cylinder chambers, and pistons in said cylinder chambers operated by said actuator means, said cylinder block having a rotary first control surface formed with cylinder ports into which said cylinder chambers open, respectively; and a stationary control means having a stationary second control surface, said control means having a low pressure inlet chamber and a high pressure outlet chamber communicating with said inlet means and said outlet means, respectively, and a set of low pressure channels and a set of high pressure channels communicating with said low pressure inlet chamber and said high pressure outlet chamber, respectively, and opening in low pressure ports and high pressure ports on said second control surface successively cooperating with said cylinder ports on said first control surface, only said high pressure channels having valve seats, respectively, and check valves in said high pressure channels, respectively, pressed by the high pressure in said high pressure outlet chamber against said valve seats, respectively, so that no high pressure fluid from said outlet means can enter a cylinder chamber in which low pressure prevails.

Claim 3

Flow control arrangement as claimed in claim 1 wherein said pump is a radial piston pump; wherein said actuator means is an eccentric ring; wherein said cylinder block has an inner cylindrical first control surface formed with angularly spaced cylinder ports; wherein said control means rotatably supports said first control surface of said cylinder block on said second control surface; wherein said low pressure inlet chamber and said high pressure outlet chamber are diametrically spaced on said control means; and wherein said low pressure channels and said high pressure channels are radial angularly spaced channels opening in circumferentially spaced low pressure ports and high pressure ports on said second cylindrical control surface for cooperation with said angularly spaced cylinder ports.

Claim 4

Flow control arrangement as claimed in claim 1 wherein said check valves are unbiassed and are freely movable balls located in said high pressure channels.

Claim 5

Flow control arrangement as claimed in claim 1 wherein said stationary control means includes aN outer cylindrical tubular body having said second control surface on the outer periphery thereof, and being formed with radial angularly spaced low pressure channels and high pressure channels passing therethrough, and a cylindrical inner body located in said outer cylindrical tubular body and having said low pressure inlet chamber and high pressure outlet chamber diametrically disposed at the periphery thereof and surrounded by said outer cylindrical tubular body so that said radial channels connect said low pressure inlet and high pressure outlet chambers with said low pressure and high pressure ports, respectively, on said second control surface.

Claim 6

Flow control arrangement as claimed in claim 1 wherein said pump is a radial piston pump; wherein said actuator means is an eccentric ring; wherein said cylinder block has an inner cylindrical first control surface formed with angularly spaced cylinder ports; wherein said control means rotatably supports said first control surface of said cylinder block on said second control surface; wherein said low pressure inlet chamber and said high pressure outlet chamber are diametrically spaced in said control means; wherein said low pressure channels and said high pressure channels are radial angularly spaced channels opening in circumferentially spaced low pressure ports and high pressure ports on said second cylindrical control surface for cooperation with said angularly spaced cylinder ports; wherein said stationary control means includes an outer cylindrical tubular body having said second control surface on the outer periphery thereof, and being formed with radial angularly spaced low pressure channels and high pressure channels passing therethrough, and a cylindrical inner body located in said outer cylindrical tubular body and having said low pressure inlet chamber and high pressure outlet chamber diametrically disposed at the periphery thereof and surrounded by said outer cylindrical tubular body so that said radial channels connect said low pressure inlet and high pressure outlet chambers with said low pressure and high pressure ports, respectively, on said second control surface.

Claim 7

Flow control arrangement as claimed in claim 5 wherein said check valves are spherical balls located in said radial high pressure outlet channels radially inward of said valve seats, respectively, and having a diameter smaller than the radial distance between the respective valve seat and the innner surface of said cylindrical tubular body so that said balls can be spaced from the outer periphery of said cylindrical inner body.

Claim 8

Flow control arrangement for a piston pump, comprising a stator having inlet means and high pressure outlet means, and including actuator means, said inlet means including an inlet duct in said stator, and a biassed throttle valve in said inlet duct, and said outlet means including an outlet duct in said stator, said stator being formed with a connecting duct connecting said outlet duct with said throttle valve for operating the same to reduce the inlet flow of fluid; a biassed outlet check valve in said connecting duct in the region of said outlet duct, and opening when the pressure in said outlet duct is too high so that pressure fluid flows through said outlet check valve and connecting duct to said throttle valve for reducing the flow cross section of said inlet duct; a rotor including a rotary cylinder block having cylinder chambers and pistons in said cylinder chambers operated by said actuator means, said cylinder block having a rotary first control surface formed with cylinder ports into which said cylinder chambers open, respectively; and a stationary control means having a stationary second control surface in sliding contact with said first control surface, said control means having a low pressure inlet chamber and a high pressure outlet chamber communicating with said inlet means and said outlet means, respectively, and a set of low pressure channels and a set of high pressure channels commuNicating with said low pressure inlet chamber and said high pressure outlet chamber, respectively, and opening in low pressure ports and high pressure ports on said second control surface successively cooperating with said cylinder ports on said first control surface, only said high pressure channels having valve seats, respectively, and check valves in said high pressure channels, respectively, pressed by the high pressure in said high pressure outlet chamber against said valve seats, respectively, so that no high pressure fluid from said outlet means can enter a cylinder chamber in which low pressure prevails, said stationary control means including an outer cylindrical tubular body having said second control surface on the outer periphery thereof, and being formed with radial angularly spaced low pressure channels and high pressure channels passing therethrough, and a cylindrical inner body located in said outer cylindrical tubular body and having said low pressure inlet chamber and said high pressure outlet chamber diametrically disposed at the periphery thereof and surrounded by said outer cylindrical tubular body so that said radial channels connect said low pressure inlet and high pressure outlet chambers with said low pressure and high pressure ports, respectively, on said second control surface, said check valve being spherical balls located in said radial high pressure outlet channels radially inward of said valve seats, respectively, and having a diameter smaller than the radial distance between the respective valve seat and the inner surface of said cylindrical tubular body so that said balls can be spaced from the outer periphery of said cylindrical inner body.

Claim 9

Flow control arrangement for a piston pump, comprising a stator having inlet means and high pressure outlet means, and including actuator means, said inlet means including an inlet duct in said stator, and a biassed throttle valve in said inlet duct, and said outlet means including an outlet duct in said stator, said stator being formed with a connecting duct connecting said outlet duct with said throttle valve for operating the same to reduce the inlet flow of fluid; a biassed outlet check valve in said connecting duct in the region of said outlet duct, and opening when the pressure in said outlet duct is too high so that pressure fluid flows through said outlet check valve and connecting duct to said throttle valve for reducing the flow cross section of said inlet duct; a rotor including a rotary cylinder block having cylinder chambers and pistons in said cylinder chambers operated by said actuator means, said cylinder block having a rotary first control surface formed with cylinder ports into which said cylinder chambers open, respectively; and a stationary control means having a stationary second control surface in sliding contact with said first control surface, said control means having a low pressure inlet chamber and a high pressure outlet chamber communicating with said inlet means and said outlet means, respectively, and a set of low pressure channels and a set of high pressure channels commuNicating with said low pressure inlet chamber and said high pressure outlet chamber, respectively, and opening in low pressure ports and high pressure ports on said second control surface successively cooperating with said cylinder ports on said first control surface, only said high pressure channels having valve seats, respectively, and check valves in said high pressure channels, respectively, pressed by the high pressure in said high pressure outlet chamber against said valve seats, respectively, so that no high pressure fluid from said outlet means can enter a cylinder chamber in which low pressure prevails, said stationary control means including an outer cylindrical tubular body having said second control surface on the outer periphery thereof, and being formed with radial angularly spaced low pressure channels and high pressure channels passing therethrough, and a cylindrical inner body located in said outer cylindrical tubular body and having said low pressure inlet chamber and said high pressure outlet chamber diametrically disposed at the periphery thereof and surrounded by said outer cylindrical tubular body so that said radial channels connect said low pressure inlet and high pressure outlet chambers with said low pressure and high pressure ports, respectively, on said second control surface, said check valve being spherical balls located in said radial high pressure outlet channels radially inward of said valve seats, respectively, and having a diameter smaller than the radial distance between the respective valve seat and the inner surface of said cylindrical tubular body so that said balls can be spaced from the outer periphery of said cylindrical inner body.

Claim 10

Flow control arrangement for a piston pump, comprising a stator having inlet means and high pressure outlet means, and including actuator means, said inlet means including an inlet duct in said stator, and a biassed throttle valve in said inlet duct, and said outlet means including an outlet duct in said stator, said stator being formed with a connecting duct connecting said outlet duct with said throttle valve for operating the same to reduce the inlet flow of fluid; a biassed outlet check valve in said connecting duct in the region of said outlet duct, and opening when the pressure in said outlet duct is too high so that pressure fluid flows through said outlet check valve and connecting duct to said throttle valve for reducing the flow cross section of said inlet duct; a rotor including a rotary cylinder block having cylinder chambers, and pistons in said cylinder chambers operated by said actuator means, said cylinder block having a rotary first cylindrical control surface formed with cylinder ports into which said cylinder chambers open, respectively; and a stationary control means having a cylindrical stationary second control surface in sliding contact with said first control surface, said control means having a low pressure inlet chamber and a high pressure outlet chamber communicating with said inlet means and said outlet means, respectively, and a set of radial low pressure channels and a set of radially high pressure channels communicating with said low pressure inlet chamber and said high pressure outlet chamber, respectively, and opening in low pressure ports and high pressure ports on said second control surface successively cooperating with said cylinder ports on said frist control surface, only said high pressure channels having valve seats, respectively, and check valves in said high pressure channels, respectively, pressed by the high pressure in said high pressure outlet chamber against said valve seats, respectively, so that no high pressure fluid from said outlet means can enter a cylinder chamber in which low pressure prevails, said sets being diametrically arranged on said second stationary cylindrical control surface, individual low pressure ports and high pressure ports being separated from each other by circumferential face portions of said second stationary cylindrical conTrol surface, the circumferential extension of said face portions of said second stationary cylindrical control surface being smaller than the diameter and the circumferential extension of said cylinder ports along said first rotary cylindrical control surface.

Claim 11

Flow control arrangement for a piston pump, comprising a stator having inlet means and high pressure outlet means, and including actuator means, said inlet means including an inlet duct in said stator, and a biassed throttle valve in said inlet duct, and said outlet means including an outlet duct in said stator, said stator being formed with a connecting duct connecting said outlet duct with said throttle valve for operating the same to reduce the inlet flow of fluid; a biassed outlet check valve in said connecting duct in the region of said outlet duct, and opening when the pressure in said outlet duct is too high so that pressure fluid flows through said outlet check valve and connecting duct to said throttle valve for reducing the flow cross section of said inlet duct; a rotor including a rotary cylinder block having cylinder chambers, and pistons in said cylinder chambers operated by said actuator means, said cylinder block having a rotary first cylindrical control surface formed with cylinder ports into which said cylinder chambers open, respectively; and a stationary control means having a cylindrical stationary second control surface in sliding contact with said first control surface, said control means having a low pressure inlet chamber and a high pressure outlet chamber communicating with said inlet means and said outlet means, respectively, and a set of radial low pressure channels and a set of radially high pressure channels communicating with said low pressure inlet chamber and said high pressure outlet chamber, respectively, and opening in low pressure ports and high pressure ports on said second control surface successively cooperating with said cylinder ports on said frist control surface, only said high pressure channels having valve seats, respectively, and check valves in said high pressure channels, respectively, pressed by the high pressure in said high pressure outlet chamber against said valve seats, respectively, so that no high pressure fluid from said outlet means can enter a cylinder chamber in which low pressure prevails, said sets being diametrically arranged on said second stationary cylindrical control surface, individual low pressure ports and high pressure ports being separated from each other by circumferential face portions of said second stationary cylindrical conTrol surface, the circumferential extension of said face portions of said second stationary cylindrical control surface being smaller than the diameter and the circumferential extension of said cylinder ports along said first rotary cylindrical control surface.