MOOG servo valve 631-3800B (USA) in stock.

Brand

MOOG/American Moog

Application Areas

Environmental Protection, Chemical Industry, Road/Rail/Marine, Automotive & Parts, General Purpose

MOOG Valves, MOOG Servo Valves, MOOG Servo Motors, MOOG Controllers, MOOG Servo Drivers, MOOG Electro-hydraulic Servo Valves, MOOG Piston Pumps

MOOG Servo Valve Working Principle

The MOOG servo valve consists of a permanent magnet torque motor, nozzle, baffle, valve core, valve sleeve, and control chamber. When current is applied to the input coil, the baffle moves to the right, strengthening the throttling effect of the right nozzle, reducing the flow rate, and increasing the back pressure on the right side; simultaneously, it reduces the throttling effect of the left nozzle, increasing the flow rate, and decreasing the back pressure on the left side. The forces at both ends of the valve core become unbalanced, causing the valve core to move to the left. High-pressure oil flows from S to C2, delivering it to the load. Load return oil flows through C1 and into the oil tank. The displacement of the valve core is proportional to the input current of the torque motor. The hydraulic pressure acting on the valve core is balanced by the spring force. Therefore, in a balanced state, the differential current of the torque motor is proportional to the displacement of the valve core. If the input current is reversed, the flow rate is also reversed. The table shows the classification of servo valves.

The MOOG servo valve is a key component in electro-hydraulic servo control developed by MOOG Corporation. It is a hydraulic control valve that receives analog electrical signals and outputs modulated flow and pressure accordingly. Electro-hydraulic servo valves have advantages such as fast dynamic response, high control accuracy, and long service life, and are widely used in electro-hydraulic servo control systems in aviation, aerospace, shipbuilding, metallurgy, and chemical industries.

On March 3, 1991, United Airlines Flight 585, a Boeing 737-291, en route from Denver International Airport to Colorado Springs Airport, experienced a sudden and uncontrollable yaw of the vertical tail rudder to the right, followed by a roll and subsequent crash to the ground. All 20 passengers and 5 crew members on board perished. On September 7, 1994, US Airways Flight 427, a Boeing 737-300, en route from Chicago O'Hare International Airport to Pittsburgh International Airport, suddenly veered out of control, rolled, and crashed to the ground, killing all 127 passengers and 5 crew members on board. Its crash pattern was similar to that of United Airlines Flight 585 and Dongfeng Airlines Flight 517. It was later discovered that the Boeing 737's rudder hydraulic system could seize under extreme temperature variations (from -50 degrees Celsius at 30,000 feet to 30 degrees Celsius at ground level, while simultaneously using high-temperature hydraulic fluid), causing the rudder to deflect in the opposite direction when the pilots took control. This malfunction showed no signs of wear and tear, and it remains one of the longest-running series of air disasters investigated by the NTSB (National Transportation Safety Board). This was the biggest fatal design flaw discovered since the Boeing 737 entered service (detailed in National Geographic's *Air Crash Investigation*, S04E04).

On June 9, 1996, Dongfeng Airlines Flight 517 experienced a sudden malfunction while preparing to land at Richmond Airport. Fortunately, only one flight attendant sustained minor injuries. The aircraft landed successfully.

Moog servo valves are primarily used as actuators in electro-hydraulic servo systems (see Hydraulic Servo Systems). In servo systems, hydraulic actuators, compared to electric and pneumatic actuators, offer advantages such as faster response, higher power output per unit weight, smoother transmission, and stronger anti-interference capabilities. Conversely, electrical components are often used for signal transmission and characteristic correction in servo systems. Therefore, modern high-performance servo systems also employ electro-hydraulic methods, and servo valves are essential components in such systems.

Moog servo valves mainly refer to electro-hydraulic servo valves. After receiving an electrical analog signal, they output modulated flow and pressure accordingly. They are both electro-hydraulic conversion elements and power amplification elements, capable of converting low-power, weak electrical input signals into high-power hydraulic energy (flow and pressure) output.

D633-333B-R16KO1F0NSS2

D633-442B-R02KO1D0VSS2

D661-4380EG60HOCA5VSX2HA

D661-4651/G35J0AA6VSX2HA

D661-4652G15JOAA6VSX2HA

D661-4697C/G15JOAA5VSX2HA

D661-4636 G60KOAA5VSX2HA

D662-4014/D01JABF6VSX2-A

D662-4337KP02HAMF6VSX2-A

D662Z4310KP02JXMF6VSX2-A

D662Z4327K /P02JXMF6VSX2-A D663Z4307K/P02JONF6VSX2-A

D664-4009L05HABF6VSX2-A

D664Z4306KP05JXNF6VSX2-A

D691-066D-6 Q20FBAABVVS0N

D691-072D Q08FBAABNVS0N

D691-087D Q60DBAABNVSON

D791-4026-S25JOQB6VSS2-B:

D661-4380EG60HOCA5VSX2HA

D661-4389EG35HOCA5VSX2HA

D662-4010/D02HABF6VSX2-A

D664Z4306KP05JXNF6VSX2-A D664-4009L05HABF6VSX2-A

D662Z4310KP02JXMF6VSX2-A

D662-4337KP02HAMF6VSX2-A

D661-4651/ G35JOAA6VSX2HA

D661-4652/ G15JOAA6VSX2HA

D661-4636/ G60KOAA5VSX2HA

D661-4469C/ G75KOAA6VSX2HA

D661-4697C/G15JOAA5VSX2HA

D661-4033/ P80HAAF6VSX2-A The company mainly deals with European and American brands and can source brands from any European country. For example, our key German brands include: BURKERT, DEMAG, HAWE, REXROTH, HYDAC, PILZ relays, FESTO, IFM sensors, E+H, HEIDENHAIN, P+F sensors, SICK, TURCK, and HIRSCHMANN industrial switches. German brands: Hengstler, Murr, Schmersal, Samson, EPRO (Emerson Group)

American brands: MOOG, ASCO, MAC, NUMATICS, PARKER, VICKERS, ROSS

British brands: Norgren

Italian brands: OMAL, ATOS, CAMOZZI, UNIVER, Camozzi