An engine mount is provided to change properties based on magnitudes of amplitudes input to the engine mount. The engine mount includes a membrane having a central portion and an outer circumferential portion. Upper and lower orifice brackets are mounted between an insulator and a diaphragm to divide an interior of a main casing into an upper liquid chamber and a lower liquid chamber. The upper and lower orifice brackets define a flow path that enables a fluid to flow between the upper and lower liquid chambers and define a receiving space in which the membrane is movable in a vertical direction. An air chamber is connected to a lower side of the lower orifice bracket and allows a lower portion of the membrane to be exposed to air.
1. An engine mount, comprising:
a membrane including a central portion and an outer circumferential portion;
upper and lower orifice brackets mounted between an insulator and a diaphragm to divide an interior of a main casing into an upper liquid chamber and a lower liquid chamber, the upper and lower orifice brackets defining a flow path that enables a fluid to flow between the upper and lower liquid chambers, and defining a receiving space in which the membrane is movable in a vertical direction; and
an air chamber connected to a lower side of the lower orifice bracket and allowing a lower portion of the membrane to be exposed to air,
wherein the upper orifice bracket has a fixing aperture into which the central portion of the membrane is inserted,
wherein the membrane freely vibrates when a magnitude of a first input amplitude is generated, and
wherein the fluid moves through the flow path when the membrane moves in the vertical direction and stops when a magnitude of a second input amplitude, which is greater than the magnitude of the first input amplitude, is generated.
2. The engine mount of claim 1 , wherein in the receiving space, upward and downward movements of the outer circumferential portion of the membrane are restricted, and the central portion of the membrane is movable in the vertical direction.
3. The engine mount of claim 1 , wherein the central portion of the membrane is thicker than other portions of the membrane.
4. The engine mount of claim 3 , wherein a lower peripheral portion of the fixing aperture is inclined, and the central portion of the membrane, which comes into contact with the lower peripheral portion of the fixing aperture, is formed to be inclined.
5. The engine mount of claim 1 , wherein the lower orifice bracket includes a first air aperture that communicates with the air chamber, and the central portion of the membrane is inserted into the air aperture.
6. The engine mount of claim 5 , wherein the central portion of the membrane is thicker than other portions of the membrane.
7. The engine mount of claim 6 , wherein an upper peripheral portion of the first air aperture is inclined, and the central portion of the membrane, which comes into contact with the upper peripheral portion of the first air aperture, is formed to be inclined.
8. The engine mount of claim 1 , wherein an adjustment unit having a second air aperture formed in a space communicating with the air chamber is formed in the lower orifice bracket to be movable in the vertical direction.
9. The engine mount of claim 8 , wherein a diameter of the second air aperture is tunable.