Hydraulic transmission system having a main pump that can be actuated continuously

摘要

A hydraulic transmission system for a vehicle is provided. The system includes a main pump serving to feed with fluid at least one hydraulic motor for driving a vehicle mover member; an auxiliary pump, the main pump and the auxiliary pump being suitable for being actuated jointly; and a “bypass” connection between a delivery orifice of the auxiliary pump and an unpressurized reservoir. In addition, a first constriction is arranged on the bypass connection, and configured to maintain a pump protection pressure in a pump protection portion of the bypass connection. This pressure is applied to the main orifices of the main pump when said pump is actuated but is not delivering, thereby ensuring that the pump is protected.

主权项

1. A hydraulic transmission system for a vehicle, the system including a non-hydraulic main transmission suitable for driving vehicle mover members, and an auxiliary transmission constituted by hydraulic transmission apparatus including:
a main pump serving to feed at least one hydraulic motor with fluid; an auxiliary pump serving to maintain some minimum fluid pressure in at least one auxiliary duct; and a pressure limiter connected to a delivery orifice of the auxiliary pump; the main pump and the auxiliary pump being suitable for being actuated jointly by drive means for the purpose of delivering pressurized fluid; and said at least one motor serving to drive at least one vehicle mover member; wherein the apparatus further includes: a bypass connection between the delivery orifice of the auxiliary pump and an unpressurized reservoir; first constriction means arranged on the bypass connection and suitable for maintaining a pump protection pressure in a pump protection portion of the bypass connection, said pump protection pressure being less than a calibration pressure of said pressure limiter; and a duct for applying said pump protection pressure to main orifices of the main pump when said pump is actuated but is not delivering.