Primary control of the shock absorber recoil is:
-
the fluid flow from the recoil chamber into the gas chamber
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the fluid flow from the gas chamber into the compression chamber.
The damping tube, which contains the first stage orifice, attaches to the head of the 2nd stage cylinder and has a fluid connection. The movement of the damping tube through the orifice block decreases the fluid flow in the 1st stage damping. This increases the damping effect. A floating piston in the 2nd stage cylinder separates the hydraulic fluid of the compression chamber and the gas of the 2nd stage chamber. During a compression stroke, the floating piston does not move down until the gas pressures of the 1st and the 2nd stage chambers are equal.
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(1) Upper Bearing
(Ref. Fig. 010)
The sliding tube connects to the main fitting by a bearing and a bearing housing. A recoil valve assembly (on the bearing housing) has a recoil-orifice-plate and recoil chamber to control the flow of fluid. An annular travel-stop inside the sliding tube is attached by the dowels which hold the bearing housing. The travel-stop touches the center tube flange when the unit is fully extended, and holds the sliding tube.
(2) Upper Diaphragm and Tube Sub-assembly
(Ref. Fig. 011)
The upper diaphragm and tube sub-assembly is connected to the main fitting by a lateral pin. The lateral pin has the 1st stage charging-valve which fills the shock absorber with hydraulic fluid or nitrogen gas. An oil-level tube goes through the diaphragm into the gas chamber. This gives the correct level of fluid in the shock absorber during the maintenance procedures.
The tube of the diaphragm and tube sub-assembly goes into the open top of the sliding tube. The top part of the tube has four holes in the area of the gas chamber. These holes permit fast separation of the fluid and the gas when the MLG leg goes from the retracted to the extended position.
A diaphragm with a baffle, is at the bottom of the diaphragm and tube sub-assembly. The baffle causes the defusion of the fluid that goes through it, to decrease the quantity of absorbed gas. The diaphragm has a compression-orifice-plate that lets full flow during the compression, but decreases the flow during the recoil. A damping tube, on the lower diaphragm, moves through the baffle. It has a set of four radially-aligned holes that give the two-stage damping effect of the shock absorber.
You can remove the shock absorber from the main fitting while it is on the aircraft. You must remove the lateral retaining pin and the main-gland lower-bearing assembly first. (To get the sufficient ground clearance, it is necessary to increase the jacked height of the aircraft).
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MLG Shock Absorber - Upper Bearing Figure 010
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MLG Shock Absorber - Upper Diaphragm Figure 011
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(3) Gland-Housing Assembly
R **ON A/C 001-049, 051-099, 101-149, 151-199, 201-299, 401-499,
(Ref. Fig. 012)
**ON A/C 301-399,
(Ref. Fig. 012A)
**ON A/C ALL
A gland-housing assembly, at the bottom end of the main-fitting barrel, seals the joint between the barrel and the sliding tube. This assembly has:
-
a gland housing, that holds the top (spare) and the bottom (main) gland seals
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a bearing, that keeps the sliding tube correctly aligned
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a wiper ring, that keeps the unwanted material out of the shock absorber.
Three threaded pins attach the gland housing and the bearing to the barrel of the main fitting. The threaded pins have greasers to lubricate the bearing.
(4) Spare-Seal Activating Valve
R **ON A/C 001-049, 051-099, 101-149, 151-199, 201-299, 401-499,
(Ref. Fig. 012)
**ON A/C 301-399,
(Ref. Fig. 012A)
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MLG Shock Absorber - Gland Housing Sub-Assembly and Spare Seal Activating-Valve
Figure 012
R 1EFF : 001-049, 051-099, 101-149, 151-199, 1 Page 3032-11-00
1201-299, 401-499, 1 Aug 01/05
1 1
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MLG Shock Absorber - Gland Housing Sub-Assembly and Spare Seal Activating-Valve
Figure 012A
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1 1 May 01/05
1 1
1CES 1
**ON A/C ALL 中国航空网 www.aero.cn 航空翻译 www.aviation.cn 本文链接地址：A320飞机维护手册 AMM LANDING GEAR 起落架1(95)
