液壓系統(tǒng)外文翻譯(編輯修改稿)
2025-02-02 09:24 本頁面
【文章內(nèi)容簡介】 rge piston is the crosssectional area S2, the pressure P on the piston in the upward pressure generated F2 = PxS2 Crosssectional area is a small multiple of the piston crosssectional area. From the type known to add in a small piston of a smaller force, the piston will be in great force, for which the hydraulic machine used to suppress plywood, oil, extract heavy objects, such as fing steel. 二． Hydraulic pump A hydraulic pump is a mechanical device which converts mechanical energy into hydraulic specifically ,a pump converts the kiic(moving) energy of a rotating shaft into the kiic energy of fluid flow. The fluid flow also has potential energy that allows it to over e the resistance of the system to fluid flow .Remember that a pump provides the force produce flow and transmit power . Hydraulic pressure is caused by the load on the system and by the resistance of the hydraulic system to fluid flow. When operating , a hydraulic pump performs two functions. First, it creates a partial vacuum at its inlet ,permitting the atmospheric pressure in the fluid reservoir to push the hydraulic fluid through the inlet strainer and line into the pump .Second, its mechanical action delivers the fluid to its outlet and into the hydraulic systems, as shown in . As the fluid leaves the pump, it encounters the working pressure in the system. This pressure is produced by the pressure regulating valve, the system work load ,and flow losses in the hydraulic tubing A pump is classified on the basis of the physical arrangement of its pumping mechanism and its basic principle of operating. Pumps classified by principle of operation include positive displacement and nonpositivedisplacementtypes. Positivedisplacementpumps ， are equipped with a mechanical separation(gears,vanes,or impellers) between the inlet and outlet, which minimizes internal leakage or slippage. Therefore,the output of positivedisplacement pumps is almost unaffected by variations in system pressure Nopositivedisplacement pumps(such as centrifugal pumps) do not have a positive internal separation against leakage or slippage. Because of this slippage,the delivery of these pump is reduced as the working pressure of a system is increased. However, nonpositivedisplacement pumps deliver a continuous flow, while positivedisplacement pumps deliver an intermittent(pulsating) flow. These pulsations are small and can be smooth out by the accumulator or the system piping. Most hydraulic pumps are positivedisplacement pumps of the rotary type. Positivedisplacement pumps have either a fixed or variable displacement. The volume of delivery ,or gpm, of a fixeddisplacement pump can be changed only by changing the speed of the pump, because the physical arrangement of the
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