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1. WO1999001644 - SYSTEME DE SOUTENEMENT AMELIORE POUR APPAREILLAGE D'EXPLOITATION MINIERE ET EQUIPEMENT DE SOUTENEMENT PAR BOULONS D'ANCRAGE

Note: Texte fondé sur des processus automatiques de reconnaissance optique de caractères. Seule la version PDF a une valeur juridique

[ EN ]

THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS:

1. Rotary valve for an internal combustion engine, comprising:
a rotor housing having an axial bore and a transfer port arranged to provide fluid communication between the bore and a combustion chamber of the engine;
a valve rotor supported for rotation within the bore, the rotor having a cylindrical main body portion which maintains a predetermined small radial clearance gap to the bore surface and having at least one fluid exchange duct terminating in an exchange port on an outer peripheral surface of the main body portion, the rotor, in use periodically enabling and preventing fluid exchange through the duct in accordace with the operating cycle of the engine;
and a sealing system, including
a set of sealing rings disposed on axially opposite sides of the transfer and the exchange ports and received pair-wise in respective single annular grooves formed either on the main body portion or within the bore, the rings and grooves being dimensioned such that the rings are received with predetermined axial play between themselves and a radial gap is formed above the groove bottom whilst the rings protrude radially from said annular grooves and either the radially outer or the radially inner circumferential surface of the rings is in substantially continuous sliding abutment against the bore surface or peripheral surface of the main body portion, as the case may be, thereby bridging said radial clearance gap in circumferential direction of the rotor,
two first longitudinal sealing elements received one each in a corresponding longitudinal groove formed either on circumferentially opposite sides close to the transfer port within the bore or on circumferentially opposite sides of a discrete ignition surface zone of the main body portion which, in operation of the valve, covers the transfer port during the ignition phase of combustion fluids in the combustion chamber, the first sealing elements protruding radially from said longitudinal grooves into sliding abutment against the bore surface or peripheral surface of the main body portion, as the case may be, thereby bridging said radial clearance gap in axial direction of the rotor, the first sealing elements having a length such as to be received between the sealing rings closest to the transfer port with a predetermined small axial clearance or play fit ; and
a pressurising system including a pressurised fluid source and conduits arranged and disposed such as to selectively direct a pressurised fluid in between each ring pair thereby to bias, at least during the ignition phase, the rings in axially opposite directions to abut against a respectively adjacent side wall of the annular grooves in which the sealing ring pairs are received, substantially isolate the transfer port from the annular grooves during the ignition phase and substantially minimise fluid leakage during this phase from the gap cavity defined between the portions of the sealing rings closest to the transfer port and of the first sealing elements that bridge the radial gap, and the facing surfaces of the bore and the main body portion.

2. Rotary valve according to claim 1 , wherein both the annular and longitudinal grooves are formed on the cylindrical main portion of the rotor.

3. Rotary valve according to claim 1 or 2, the main body portion comprising separate fluid intake and fluid exhaust ducts respectively commencing on axially opposite sides of the main body portion and terminating in an intake and an exhaust port which are spaced apart in circumferential direction on the outer peripheral surface of the main body portion; and
wherein the valve further comprises a plurality of second longitudinal sealing elements received one each in a corresponding one of a plurality of additional longitudinal grooves on the peripheral surface of the main body portion, said second sealing elements disposed to provide
a leading and a trailing sealing element for the intake port,
a leading and a trailing sealing element for a discrete surface zone associable with the compression phase of the operating cycle,
the leading and the trailing sealing element for the discrete ignition surface zone being provided by said first sealing elements,
an optional leading and a trailing sealing element for a discrete surface zone associable with the expansion phase of the operating cycle,
a leading and a trailing sealing element for the exhaust port,
thereby forming at least four discretely framed gap cavities over the discrete surface zones associable with the operating phases of the engine and which rotate with the rotor.

4. A rotary valve according to claim 3, wherein the trailing sealing element of the intake port, the trailing sealing element of the surface zone associable with the ignition phase and the trailing sealing element of the surface zone associable with the expansion phase provide the leading sealing element of the surface zone associable with the compression phase, the optional leading sealing element of the surface zone associable with the expansion phase and the leading sealing element of the exhaust port, respectively.

5. Rotary valve according to claim 3 or 4, wherein at least the leading first longitudinal sealing element for the discrete ignition surface zone and optionally selected ones of the remaining first and second longitudinal sealing elements consist each of a pair of axial sealing blades received in parallel with predetermined play in circumferential direction in the corresponding axially extending longitudinal grooves formed on the main body portion;
and wherein the pressurising system includes conduits disposed such as to direct the pressurised fluid in between each sealing blade pair thereby to bias the blades in circumferentially opposite directions to abut against a respectively adjacent side wall of the longitudinal groove in which each sealing blade pair is received, the pressure level imparted on the fluid and the timing of pressurisation being such that the blades are maintained in abutment against the respective side wall at least during the ignition phase of the operating cycle of the engine.

6. Rotary valve according to any one of claims 2 to 5, further comprising sealing ring biasing means arranged to bias the rings in radial direction so as to maintain sliding contact against the bore surface.

7. Rotary valve according to claim 6, wherein the sealing rings are piston rings with a predetermined ring end gap.

8. Rotary valve according to claim 6, wherein the sealing rings are piston rings with overlapping ring ends.

9. Rotary valve according to claim 6, wherein the sealing ring biasing means comprise radially expandable sealing rings.

10. Rotary valve according to any one of the preceding claims, further comprising sealing ring distance keeping means arranged to maintain an axial gap between the sealing rings when received in the annular groove.

11. Rotary valve according to claim 10, wherein the sealing ring distance keeping means comprise axial biasing means arranged to maintain the rings in abutment against the respectively adjacent side wall of the annular groove in which each sealing ring pair is received.

12. Rotary valve according to claim 1 1 , wherein the sealing ring distance keeping means comprises a conical or undulating spring washer.

13. Rotary valve according to claim 11 , wherein a spreading ring is arranged between the sealing rings in each groove, the spreading ring being trapezoidal in radial cross-section, and which co-operates with correspondingly shaped inclined portions of the radially extending side faces of the sealing rings that face the spreading ring, thereby to simultaneously bias the sealing rings in radial and in axially opposite directions into sealing engagement with the valve bore surface and the side wall surfaces of the annular groove.

14. Rotary valve according to claim 13, wherein a lubricant gallery channel is defined between an outer circumferential surface of the spreading ring and channel side surfaces formed on the facing side surfaces of the sealing rings.

15". Rotary valve according to claim 14, wherein a plurality of circumferentially spaced apart lubricant feeding holes extend from one of the side faces of the sealing rings to end in one of the side surfaces of the lubricant gallery channel.

16. Rotary valve according to any one of claims 1 to 15, further comprising sealing blade biasing means arranged to bias the blades in radial direction so as to maintain sliding contact against the bore surface.

17. Rotary valve according to claim 16, wherein the sealing blade biasing means comprise a leaf spring received in the longitudinal groove below the sealing blades.

18. Rotary valve according to claim 16 or 17, further comprising sealing blade distance keeping means arranged to maintain a longitudinally extending gap between the sealing blades when received in the associated longitudinal groove.

19. Rotary valve according to claim 18, wherein the sealing blade distance keeping means comprise circumferentially acting biasing means arranged to maintain the blades in abutment against the respectively adjacent side wall of the longitudinal groove in which each sealing blade pair is received.

20. Rotary valve according to claim 19, wherein the sealing blade distance keeping means comprises a leaf or undulated band spring.

21. Rotary valve according to any one of the preceding claims, wherein the pressurised fluid source is a pressurised air source.

22. Rotary valve according to claim 21 , wherein the pressurised air source is a compressor or turbo charger of the engine.

23. Rotary valve according to claim 21 , wherein the pressurised air source is arr intake manifold of the engine whilst under positive pressure.

24. Rotary valve according to claim 21 , wherein the pressurised air source is a cylinder of the engine in which a piston reciprocates in accordance with the operating cycle of the engine.

25. Rotary valve according to claim 24, wherein the pressurised air source is in fluid communication with the conduits during at least part of the compression phase of the operating cycle of the engine.

26. Rotary valve in accordance with any one of claims 1 to 25, wherein the pressurised fluid is a cooling fluid for the sealing elements.

27. Rotary valve according to any one of claims 3 to 26, wherein the annular grooves for the sealing rings and at least the longitudinal groove for the leading first sealing element for the ignition surface zone are in fluid communication with one another when the respective sealing rings and elements are received therein, said grooves forming part of or being the conduits.

28. Rotary valve according to any one of claims 3 to 26, wherein the annular grooves for the sealing rings and all the longitudinal grooves for the longitudinal sealing elements are in fluid communication with one another when the respective sealing rings and elements are received therein, said grooves forming part of or being a network of interconnected conduits;
and wherein the first and second longitudinal sealing elements consist each of a pair of axial sealing blades received in parallel with predetermined play in circumferential direction in the corresponding axially extending longitudinal grooves formed on the main body portion;
the pressurising system disposed such as to direct the pressurised fluid in between each sealing blade pair thereby to bias the blades in circumferentially opposite directions to abut against a respectively adjacent side wall of the longitudinal groove in which each sealing blade pair is received, the pressure level imparted on the fluid and the timing of pressurisation being such that the blades are maintained in abutment against the respective side wall during the operating cycle of the engine.