Patent ID: 6464482
Filing Date: 2002-10-15
Classification: F04C

Abstract:
Roller vane pump suitable for pumping transmission fluid in an automatic transmission for motor vehicles, in particular a continuously variable transmission, comprising:a pump housing (2); a drivably rotatable carrier (3) having a substantially circular cross section and being located in the interior of the pump housing (2), at its radial periphery being provided with slots (6) that extend in a direction substantially inward from the periphery; a cam ring (5) having a non-circular inner surface (5a) and surrounding the carrier (3) in radial direction; substantially cylindrical roller elements (7) being slidably provided in the slots (6) of the carrier (3), wherein the spaces between the pump housing (2), the carrier (3), the cam ring (5) and the roller elements (7) define pump chambers (8), wherein said pump chambers (8) are divided into cam chambers (8b) and carrier chambers (8a), the cam chambers (8b) ranging from tangential centre planes of the roller elements (7) radially outward, and the carrier chambers (8a) ranging from tangential centre planes of the roller elements (7) radially inward, each carrier chamber (8a) being associated with a leading cam chamber (8b) in rotational direction and a trailing cam chamber (8b) in anti-rotational direction; at least one feed aperture (9) having a substantially elongated shape, a long axis of said feed aperture (9) extending in a substantially tangential direction, said feed aperture (9) being arranged in the pump housing (2) such that at least one pump chamber (8) is associated with a feed channel (11) in the pump housing (2) through the feed aperture (9), wherein said feed aperture (9) is divided into an inner feed aperture (9a) and an outer feed aperture (9b) by a ridge (12) having an inner surface (12a) and an outer surface (12b), said surfaces (12a,12b) extending in a substantially axial direction as well as in a substantially tangential direction; and at least one discharge aperture (10) having a substantially elongated shape, a long axis of said discharge aperture (10) extending in a substantially tangential direction, said discharge aperture (10) being arranged in the plump housing (2) such that at least one pump chamber (8) is associated with a discharge channel in the pump housing (2) through the discharge aperture (10), wherein said discharge aperture (10) is divided into an inner discharge aperture (10a) and an outer discharge aperture (10b) by a ridge (12) having an inner surface (12a) and an outer surface (12b), said surfaces (12a,12b) extending in a substantially axial direction as well as in a substantially tangential direction, wherein the feed aperture (9) is shaped such that the leading cam chamber (8b) arrives into communication with the outer feed aperture (9b) before the corresponding carrier chamber (8a) arrives into communication with the inner feed aperture (9a); wherein the discharge aperture (10) is shaped such that the carrier chamber (8a) arrives into communication with the inner discharge aperture (10a) before corresponding leading cam chamber (8b) arrives into communication with the outer discharge aperture (10b); wherein the feed aperture (9) is further shaped such that the communication between the carrier chamber (8a) and the inner feed aperture (9a) is cut off before the communication between the leading cam chamber (8b) and the outer feed aperture (9b) is cut off; and wherein the discharge aperture (10) is further shaped such that the communication between the leading cam chamber (8b) and the outer discharge aperture (10b) is cut off after the communication between the carrier chamber (8a) and the inner discharge aperture (10a) is cut off.