Cooled hydraulic system

Claim 2

A hydraulic system containing a relatively incompressible hydraulic medium and having a pressure line, a return line, means to pump the medium from the return line to the pressure line and at least one actuator to use the energy of the medium in the pressure line and return the medium to the return line, the improvement comprising: bypass means connected between the pressure and return lines which allow a predetermined flow of medium between the pressure and return lines, whereby a predetermined flow of medium is assured in a portion of the pressure and return lines, which flow carries heat which is dissipated along the pressure and return lines, said heat being dissipated along the pressure and return lines being greater than the heat injected into said system by the pumping means in pumping said predetermined flow to assure that said hydraulic medium remains below a predetermined temperature.

Claim 3

The system defined in claim 1 wherein said bypass means are sized to allow a flow of medium which is less than the flow for causing minimum temperatures of the hydraulic medium within the operating system so that as said bypass means wear and allow more flow, the temperatures of the hydraulic medium within the system become lower.

Claim 4

The system defined in claim 1 wherein said bypass means are located adjacent the actuator so that a large proportion of the pressure and return lines are used to dissipate heat.

Claim 5

The system defineD in claim 1 having a plurality of actuators and pressure and return lines between the actuators and the pump means, said bypass means being connected adjacent selected actuators chosen because the pressure and return lines connected thereto have relatively high heat dissipation characteristics.

Claim 6

In a hydraulic system having undesired heat injected into the hydraulic medium by pumping losses therein: means to induce a continuous predetermined flow of hydraulic medium in selected lines of said system so that more of said heat is dissipated from said medium by said selected lines than is produced by the heat injected into said medium because of said predetermined flow.

Claim 7

In a hydraulic system having undesired heat injected into the hydraulic medium by pumping losses therein: means to induce a continuous predetermined flow of hydraulic medium in selected lines of said system so that more of said heat is dissipated from said medium by said selected lines than is produced by the heat injected into said medium because of said predetermined flow.

Claim 8

The system defined in claim 5 wherein said flow inducing means include a bypass restrictor.

Claim 9

The system defined in claim 5 wherein said flow inducing means include a hydraulic actuator incorporating means to assure a predetermined medium leakage therethrough.

Claim 10

A hydraulic system for an aircraft, said system including: a supply of hydraulic fluid; fluid distributing lines; means to pump said hydraulic fluid from said supply into said fluid distributing lines at a predetermined pressure, said means injecting undesired heat into said fluid; fluid return lines connected to said supply; actuators connected to use said pressurized fluid in said fluid distributing lines and to return said fluid to said fluid return lines; and means in communication with selected fluid distributing and fluid return lines to enable predetermined flows of fluid therethrough, said selected fluid distributing and fluid return lines being selected because of their ability to dissipate relatively more heat than the non-selected lines and said predetermined flows of fluid acting to transport said undesired heat in the fluid within said selected fluid distributing and fluid return lines so that more of said heat is dissipated therefrom than is generated by said pump means in pumping said predetermined flows.

Claim 11

A hydraulic system for an aircraft, said system including: a supply of hydraulic fluid; fluid distributing lines; means to pump said hydraulic fluid from said supply into said fluid distributing lines at a predetermined pressure, said means injecting undesired heat into said fluid; fluid return lines connected to said supply; actuators connected to use said pressurized fluid in said fluid distributing lines and to return said fluid to said fluid return lines; and means in communication with selected fluid distributing and fluid return lines to enable predetermined flows of fluid therethrough, said selected fluid distributing and fluid return lines being selected because of their ability to dissipate relatively more heat than the non-selected lines and said predetermined flows of fluid acting to transport said undesired heat in the fluid within said selected fluid distributing and fluid return lines so that more of said heat is dissipated therefrom than is generated by said pump means in pumping said predetermined flows.

Claim 12

The system defined in claim 8 wherein said selected fluid distributing and fluid return lines are those lines which extend most toward the extremities of the aircraft.

Claim 13

The system defined in claim 8 wherein said flow enabling means include: means which tend to wear in operation and increase the flow enabled thereby, said flow enabling means being initially sized for a flow that produces less heat dissipation and a higher fluid temperature than is possible; whereby wear of said flow enabling means causes, up to a certain point, lower fluid temperatures in the system.

Claim 14

The system defined in claim 8 wherein selected actuators include said flow enabling means.

Claim 15

The system defined in claim 8 wherein said flow enabling means are bypass restrictors positioned adjacent selected actuators and connected between said fluid distributing lines and fluid return lines connected to said selected actuators.