초록 ▼

The pump (5) has at least one cylinder (6) in which slides a piston (16) moved positively in the compression direction and elastically in the intake direction. A compression spring (26) is located between the shutter (21) of an intake valve (19) and the piston (16) to push the shutter (21) elastical

The pump (5) has at least one cylinder (6) in which slides a piston (16) moved positively in the compression direction and elastically in the intake direction. A compression spring (26) is located between the shutter (21) of an intake valve (19) and the piston (16) to push the shutter (21) elastically into a closed position by exerting elastic force varying according to the position of the piston (16). The shutter (21) has a plate (28) cooperating with a seat (22) on the intake valve (19) and moveable parallel to the piston (16); and the compression spring (26) acts on the plate (28) to advance both opening and closing of the intake valve (19).

대표청구항 ▼

1. A high-pressure hydraulic pump comprising at least one cylinder (6) in which slides a piston (16), and actuating means (9, 11) for moving said piston (16) positively in a compression direction; said piston (16) being moved elastically in an intake direction opposite to said compression direction;

1. A high-pressure hydraulic pump comprising at least one cylinder (6) in which slides a piston (16), and actuating means (9, 11) for moving said piston (16) positively in a compression direction; said piston (16) being moved elastically in an intake direction opposite to said compression direction; and an intake valve (19) comprising a shutter (21) being fitted to said cylinder (6); characterized in that elastic means (26) are provided between said piston (16) and said shutter (21) to push said shutter (21) into a closed position by exerting elastic force varying with the position of said piston (16) in said cylinder (6), so as to advance opening and closing of said intake valve (19). 2. A pump as claimed in claim 1, wherein said shutter (21) comprises a plate (28) cooperating with a seat (22) of said intake valve (19); said plate (28) being movable parallel to said piston (16); characterized in that said elastic means comprise a compression spring (26) located between said plate (28) and said piston (16). 3. A pump as claimed in claim 2, characterized in that said shutter (21) also comprises a stem (29) integral with said plate (28) and extending radially outwards; said stem being guided inside an axial hole (31) of a valve body (23) of said intake valve (19). 4. A pump as claimed in claim 3, characterized in that said seat (22) is truncated-cone-shaped, flaring towards said piston (16); said plate (28) having, on the side facing said stem, a truncated-cone-shaped edge (35) complementary to the shape of said seat (22). 5. A pump as claimed in claim 4, characterized in that said plate comprises, on the opposite side to said stem, a cylindrical projection (34) for securing one end of said spring (26). 6. A pump as claimed in claim 4, characterized in that said piston (16) has a cylindrical appendix (36)coaxial with said plate (28) and for securing another end of said spring (26). 7. A pump as claimed in claim 3, wherein said seat (22) is coaxial with said cylinder (6) 15 and is carried by a valve body (23) fitted to said cylinder (6); said valve body (23) having a supply conduit (32); characterized in that said valve body (23) is bell-shaped for housing at least part of said spring (26). 8. A pump as claimed in claim 3, characterized in that said axial hole (31) has an enlargement (30) communicating with said supply conduit (32). 9. A pump as claimed in claim 8, of the radial-piston type for internal combustion engine fuel, comprising a hollow body (7) closed by a flange (8); said hollow body (7) carrying a group of radial cylinders (6) associated with a corresponding group of pistons (16) and with a corresponding group of intake valves (19); and said pistons (16) being activated by a common eccentric (11); characterized in that each of said valve bodies (23) if fitted inside said hollow body (7) by means of a fluidtight fastening member (24); said fastening member (24) being fittable to said hollow body (7) from the outside. 10. A pump as claimed in claim 9, characterized in that the supply conduit (32) of each valve body (23) communicates with a supply channel (33) formed in said hollow body (7) and/or in said flange (8).