Patent ID: 8857172
Filing Date: 2014-10-14
Classification: B60K,F16H

Abstract:
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.