Hydraulic vane motors require what to help seal the vanes against the cam ring before the oil assists in operation?

Hydraulic vane motors utilize springs to help seal the vanes against the cam ring before the hydraulic fluid plays a role in operation. This sealing is crucial because it ensures that the vanes make full contact with the cam ring, providing an effective chamber for hydraulic fluid pressure to act upon.

Once the motor begins to operate, the hydraulic fluid enters the motor cavity, and the pressure further assists in maintaining this seal. However, during the initial stages of operation, especially when starting up, the springs ensure that the vanes are properly positioned against the cam ring, thus preventing any leakage and maximizing efficiency.

Other components like oil pressure, centrifugal force, and intra vanes, while relevant in the operation of hydraulic systems, do not serve the same initial function of sealing the vanes prior to fluid assistance.