Flow control valve

• US 20060065870A1
• Filed: 09/26/2005
• Published: 03/30/2006
• Est. Priority Date: 09/24/2004
• Status: Active Grant

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: Mori, Katsumi, Fujii, Hiroto, Akashi, Nobuhiro
• Granted Patent: US 7,730,875 B2
• Time in Patent Office: Days
• US Class Current: 251/129.70
• CPC Class Codes: F02M 59/34 by throttling of passages to pumping elements or of overflow passages , e.g. throttling by means of a pressure-controlled sliding valve having liquid stop or abutment
• CPC Class Codes: F02M 59/366 Valves being actuated electrically
• CPC Class Codes: F02M 63/0017 using electromagnetic operating means
• CPC Class Codes: F02M 63/004 Sliding valves, e.g. spool valves, i.e. whereby the closing member has a sliding movement along a seat for opening and closing
• CPC Class Codes: F02M 63/0225 Fuel-injection apparatus having a common rail feeding several injectors F02M63/0003 takes precedence; Means for varying pressure in common rails; Pumps feeding common rails
• CPC Class Codes: F16K 3/262 with a transverse bore in the valve member
• CPC Class Codes: F16K 31/0648 the armature and the valve member forming one element F16K31/0651 takes precedence
• CPC Class Codes: F16K 31/0668 Sliding valves

Abstract

A spool valve is movably provided in a valve sliding space of a valve casing. The spool valve has a through-hole formed in the inside thereof, and a communication port formed in the spool valve is operatively communicated with a fluid port for controlling an opening area of the fluid port by moving within the valve sliding space. Multiple circular oil grooves are formed at an outer peripheral surface of the spool valve, into which high pressure fluid is supplied so that the spool valve can be smoothly moved in the valve sliding space.

Claims

1. A flow control valve comprising:

a valve casing having a cylindrical body portion and a closed end portion, a valve sliding space being formed in the cylindrical body portion, one end of the valve sliding space forming a first fluid port and the other end of the valve sliding space being closed by the closed end portion, a second fluid port being formed in the cylindrical body portion and extending in a radial direction perpendicular to an axial line of the valve casing;

a spool valve movably supported in the valve sliding space of the valve casing and movable in an axial direction of the valve casing, a through-hole being formed in the spool valve for communicating both of first and second axial ends of the spool valve with each other, a first communication port being formed in the spool valve for communicating the through-hole with an outside of the spool valve, the first communication port being operatively communicated with the second fluid port of the valve casing when the spool valve is moved in the axial direction, and an outer surface of the spool valve being substantially fluid-tightly in a sliding contact with an inner surface of the valve sliding space of the valve casing;

a fluid space formed in the valve sliding space and defined by the closed end portion and the spool valve, the fluid space being communicated with the through-hole of the spool valve; and

a spring disposed in the fluid space for biasing the spool valve in an axial direction of the spool valve,

wherein the flow control valve is characterized in that;

a first circular groove is formed at the outer surface of the spool valve communicated with the first communication port, so that the first communication port is operatively communicated with the second fluid port through the first circular groove, wherein an opening area of the second fluid port is changed depending on a relative position of the spool valve with respect to the valve casing in order that flow amount of the fluid flowing through the second fluid port is controlled;

a first and second sliding surface portions are formed by the outer surface at both axial sides of the first circular groove; and

multiple circular oil grooves are formed at the first and second sliding surface portions, wherein the fluid flows into the multiple circular oil grooves so that the spool valve is smoothly moved in the axial direction within the valve sliding space.

2. A flow control valve according to claim 1, wherein

a second circular groove is formed at the outer surface of the spool valve between the first circular groove and the second sliding surface portion of the spool valve;

and

a second communication port is formed in the spool valve for communicating the through-hole with the second circular groove, so that high pressure fluid is supplied from the through-hole to the second circular groove through the second communication port to carry out a centering of the spool valve within the valve sliding space.

3. A flow control valve according to claim 2, wherein

a circular seal portion is formed on the outer surface of the spool valve between the first and second circular grooves, so that the first and second circular grooves are fluid tightly sealed from each other.

4. A flow control valve according to claim 1, wherein

a first longitudinal groove is formed on the first sliding surface portion, extending in the axial direction of the spool valve from the first axial end to the first circular oil groove, so that high pressure fluid flows into the first circular oil groove.

5. A flow control valve according to claim 1, wherein

a second longitudinal groove is formed on the second sliding surface portion, extending in the axial direction of the spool valve from the second axial end to the second circular oil groove, so that high pressure fluid flows into the second circular oil groove.

6. A flow control valve according to claim 1, wherein

a second circular groove is formed at the outer surface of the spool valve between the first circular groove and the second sliding surface portion of the spool valve;

a longitudinal groove is formed on the second sliding surface portion, extending in the axial direction of the spool valve from the second axial end to the second circular groove, so that high pressure fluid flows from the fluid space into the second circular groove through the longitudinal groove to carry out a centering of the spool valve within the valve sliding space.

7. A flow control valve according to claim 2, wherein

a center line of the second communication port is displaced from a radial line extending in a radial direction of the spool valve, when viewed on a plane perpendicular to the axial line of the spool valve, so that the spool valve is rotated within the valve sliding space when the high pressure fluid flows out of the through-hole into the second circular groove through the second communication port.

8. A flow control valve according to claim 1, wherein

a center line of the first communication port is displaced from a radial line extending in a radial direction of the spool valve, when viewed on a plane perpendicular to the axial line of the spool valve, so that the spool valve is rotated within the valve sliding space when the high pressure fluid flows out of the through-hole into the first circular groove through the first communication port.

9. A flow control valve according to claim 1, wherein

the flow control valve is used in a common rail fuel injection system for a diesel engine, which comprises;

a common rail for accumulating high pressure fuel;

a high pressure fuel pump for pressurizing the fuel and supplying the high pressure fuel into the common rail; and

a low pressure pump for feeding the low pressure fuel to the high pressure pump, wherein

the flow control valve is arranged in a fuel supply line for feeding the low pressure fuel from the low pressure pump to the high pressure pump, in order that the flow control valve controls flow amount of the fuel from the low pressure pump to the high pressure pump.

10. A flow control valve according to claim 9, wherein

a center line of the first communication port is displaced from a radial line extending in a radial direction of the spool valve, when viewed on a plane perpendicular to the axial line of the spool valve, so that the spool valve is rotated within the valve sliding space when the high pressure fluid flows out of the through-hole into the first circular groove through the first communication port.

11. A flow control valve according to claim 10, wherein

the fuel pressure in the common rail-is controlled in such a manner that the fuel pressure is controlled at a predetermined value in the case in which an operational condition of the engine meets a predetermined condition, wherein the predetermined value is higher than the fuel pressure in the other cases in which the operational condition of the engine does not meet the predetermined condition.

12. A flow control valve according to claim 11, wherein

the operational condition of the engine meets the predetermined condition, when an engine rotational speed is within a predetermined range, and a fuel injection amount is within a predetermined amount.

13. A flow control valve according to claim 1, wherein

a foreign material exhausting passage is formed in at least one of the spool valve and the valve casing,

the foreign material exhausting passage extend from the fluid space to the second fluid port or to the first communication port, and

the foreign material exhausting passage bypasses the through-hole.

14. A flow control electromagnetic valve comprising:

a valve casing having a valve sliding space formed in an axial direction and a fluid port opening at an intermediate portion of the valve sliding space;

a spool valve having a sliding portion moved in the valve sliding space of the valve casing and controlling flow amount; and

a solenoid coil for generating magnetomotive force when electric current is supplied, and for moving the sliding portion of the spool valve relative to the fluid port of the valve casing,

wherein the spool valve has a valve function for changing an opening area of a flow passage at the fluid port by moving in the valve sliding space, and has an armature function being magnetized when the electric current is supplied to the solenoid coil,

wherein the flow control electromagnetic valve is characterized in that;

a first inner flow passage is formed in the inside of the valve casing for flowing fluid therein,

a second inner flow passage is formed in the inside of the spool valve for flowing fluid therein,

a circular flow passage is formed between an inner surface of the valve sliding space and an outer peripheral surface of the sliding portion of the spool valve, and the fluid is supplied to the circular flow passage from the first inner flow passage or the second flow passage.

15. A flow control electromagnetic valve according to claim 14, wherein

the circular flow passage is a circular centering groove formed at an intermediate portion of the sliding portion of the spool valve for centering the spool valve within the valve sliding space.

16. A flow control electromagnetic valve according to claim 15, wherein

the spool valve is a spool type valve of a sleeve shape, in the inside of which the second inner flow passage is formed,

the spool type valve has a communication port communicating the second inner flow passage with the centering groove, and

the communication port is formed at a position eccentric to a perpendicular line of a center axis of the spool type valve, and penetrates through the spool type valve.

17. A flow control electromagnetic valve according to claim 15, wherein

a circular flow amount adjusting groove is formed at an intermediate portion of the sliding portion of the spool valve, for controlling the flow amount of the fluid by changing the opening area of the flow passage at the fluid port.

18. A flow control electromagnetic valve according to claim 17, wherein

the sliding portion comprises;

two sliding surface portions positioned at both sides of the flow amount adjusting groove, and

another sliding surface portion positioned at one side of the above first-mentioned sliding surface portions in an axial direction of the spool valve,

the centering groove is formed between the first-mentioned and second-mentioned sliding surface portions, and

the flow amount adjusting groove is formed between the adjacent first-mentioned sliding surface portions.

19. A flow control electromagnetic valve according to claim 18, wherein

a communication port is formed at an outer peripheral surface of the sliding portion, for communicating the first inner flow passage with the centering groove,

a sealing portion is formed between the outer peripheral surface of the sliding portion of the spool valve and the inner surface of the valve sliding space, for liquid tightly sealing the flow amount adjusting groove from the centering groove.

20. A flow control electromagnetic valve according to claim 14, wherein

the flow control electromagnetic valve is used in a common rail fuel injection system, and assembled to a pump valve casing of a fuel supply pump for pressurizing fuel fed from a feed pump into a pressurizing chamber through the flow control electromagnetic valve, and

the flow control electromagnetic valve controls fuel discharge amount of the fuel discharged from the fuel supply pump to a common rail, by controlling suction amount of the fuel supplied from the feed pump into the pressurizing chamber.

21. In a flow control valve comprising:

a cylindrical spool valve having an inner flow passage into which fluid flows, and a communication port for flowing out the fluid having flown into the inner flow passage to an outside peripheral side;

a valve casing, into which the spool valve is movingly inserted, and into which the fluid having flown out from the communication port flows; and

a solenoid coil for generating magnetomotive force when electric current is supplied, and for moving the spool valve relative to the valve casing,

wherein flow amount of the fluid flowing through the communication port is controlled by a movement of the spool valve,

the flow control valve is characterized in that;

the communication port extends in a direction perpendicular to an axial line of the spool valve and an axial line of the communication port is displaced from the axial line of the spool valve when viewed in the direction of the axial line of the spool valve.

22. In a common rail fuel injection system comprising:

a common rail for accumulating high pressure fuel to be injected into a combustion chamber of an engine;

a high pressure pump for supplying the high pressure fuel to the common rail;

a low pressure pump for feeding fuel from a fuel tank into the high pressure pump; and

the flow control valve of claim 21,

wherein the common rail fuel injection system is characterized in that

the flow control valve is provided in a suction flow passage for feeding the fuel from the low pressure pump to the high pressure pump and controls the flow amount of the fuel to be fed from the low pressure pump to the high pressure pump.

23. A common rail fuel injection system according to claim 22, wherein

the fuel pressure in the common rail of a case in which a certain operational condition of the engine is satisfied is controlled to be higher than the fuel pressure of a case in which the certain condition is not satisfied.

24. A common rail fuel injection system according to claim 23, wherein

the certain operational condition of the engine is regarded as being satisfied when an engine rotational speed is within a predetermined range and a fuel injection amount into the engine is within a predetermined range.

25. A flow control valve comprising:

,

a cylindrical valve casing having a fluid port, which opens in a radial direction perpendicular to an axial direction of the valve casing; and

a spool valve movably supported within a valve sliding space of the valve casing for changing an opening area of the fluid port by moving in the axial direction of the valve casing;

wherein the flow control valve is characterized in that;

the valve casing has a closed end for forming an inner space with one end of the spool valve in the axial direction,

the spool valve has a through-hole penetrating the spool valve in the axial direction to communicate both axial ends, and a communication port branching off from an intermediate portion of the through-hole and extending toward an adjacent area of the fluid port, and

a foreign material exhausting passage is formed at the valve casing or the spool valve, wherein the passage bypasses the through-hole and extends from the inner space toward the fluid port or the communication port.

26. A flow control valve according to claim 25, wherein

the foreign material exhausting passage is a recess formed at an outer periphery of the spool valve.

27. A flow control valve according to claim 26, wherein

the recess extends in parallel to the axial direction of the spool valve from the inner space toward the fluid port or the communication port.

28. A flow control valve according to claim 25, wherein

the foreign material exhausting passage is a communication passage formed in the inside of the spool valve.

29. A flow control valve according to claim 28, wherein

the foreign material exhausting passage extends from the inner space toward the fluid port or the communication port and is inclined with the axial direction of the spool valve.

30. A flow control valve according to claim 25, wherein

the flow control valve further comprises a spring for biasing the spool valve in a direction of closing or opening the fluid port, and

the inner space is operated as a spring space for accommodating the spring.

31. A flow control valve according to claim 25, wherein

the valve casing has a cylinder portion for forming an axial space in the inside thereof, the axial space working as the valve sliding space,

the cylinder portion movably supports the spool valve in the axial space,

the spool valve has a sliding portion which slides in an inner surface of the cylinder portion in the axial direction, and

the communication port opens at an intermediate portion of the sliding portion and has a circular circumferential groove to be communicated with the fluid port.