There is provided a hydraulic power drive unit (PDU) (30) for a transmission system (20). The hydraulic PDU comprises: a hydraulic motor (31) for converting hydraulic pressure into torque and rotation; a hydraulic brake system (32) for applying a braking force to the hydraulic motor to prevent rotation of the hydraulic motor, wherein the hydraulic brake system is biased to apply the braking force to the hydraulic motor to prevent rotation of the hydraulic motor, and configured to remove the braking force in response to a supply of hydraulic fluid; and a hydraulic circuit (33) for supplying a flow of hydraulic fluid to the hydraulic motor to pressurise and thereby operate the hydraulic motor and for supplying hydraulic fluid to the hydraulic brake system to pressurise the hydraulic brake system and thereby remove the braking force; wherein the hydraulic circuit comprises a brake supply line (39b) for supplying the hydraulic fluid to the hydraulic brake system. The brake supply line comprises a flow restricting device to restrict backflow of the hydraulic fluid in the brake supply line away from the hydraulic brake system; such that the hydraulic circuit is configured to enable depressurisation of the hydraulic motor whilst simultaneously preventing depressurisation of the hydraulic brake system thereby preventing application of the braking force.
HYDRAULIC POWER DRIVE UNIT
ANTRIEBSEINHEIT MIT HYDRAULISCHER LEISTUNG
UNITÉ D'ENTRAÎNEMENT HYDRAULIQUE
2022-06-01
Patent
Electronic Resource
English
HYDRAULIC UNIT, DRIVE DEVICE COMPRISING HYDRAULIC UNIT, METHOD FOR OPERATING HYDRAULIC UNIT
European Patent Office | 2023
|Variable-Displacement Hydraulic Drive Unit
NTRS | 1986
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