Dongfeng LoongGine Gearbox Assy parts normally closed switch assembly V3197871

Built to serve as a safety-critical control element in LoongGine gearboxes, this assembly features a precision mechanical normally closed design that ensures fail-safe operation. In the default state (no external force), the switch maintains a closed circuit, transmitting a continuous signal to the TCU to confirm gear position or hydraulic pressure status. When triggered by shift lever movement or pressure changes (1.2-1.5MPa actuation force), it immediately opens the circuit, sending a signal to the TCU to initiate shift logic adjustments. The switch’s contact bounce time is ≤1ms, preventing false signals that could cause gear shifting errors. This reliable on-off control reduces gearbox malfunction rates by 40% and ensures smooth power transmission during heavy-haul operations

Engineered to endure the harsh operating environment inside LoongGine gearboxes, the switch assembly boasts a durable construction. The housing is made of high-strength PA66+GF30 plastic, resisting mechanical impact and deformation under 500N axial load. The internal contact points use silver-plated copper alloy, ensuring low contact resistance (≤0.01Ω) and preventing oxidation after 100,000 on-off cycles. A stainless steel spring (304 grade) provides consistent actuation force, maintaining performance even with long-term use. The assembly withstands gearbox vibrations up to 15g (5-2000Hz, ISO 16750-3) and hydraulic oil pressure up to 2.5MPa, avoiding leakage or structural damage during extreme working conditions

Designed to adapt to the oil-immersed and high-temperature environment of gearboxes, the switch assembly exhibits exceptional resistance. The housing and seals use fluororubber (FKM) material that is compatible with all common gearbox lubricants (mineral oil, synthetic oil), with no swelling (volume change ≤2%) after 72-hour oil immersion. It operates stably at temperatures ranging from -40℃ (northeast China winters) to 120℃ (gearbox peak temperature), passing 500 thermal cycles (-30℃ to 110℃) without seal hardening or contact failure. The connector’s double O-ring seal prevents oil intrusion into the electrical contacts, while the plastic housing resists aging from long-term oil exposure, ensuring a service life of ≥800,000km

Optimized for efficient gearbox maintenance, the switch assembly features a user-friendly design that simplifies replacement and reduces downtime. The M12×1.5 threaded base allows tool-free installation with a standard wrench, requiring only 15-20N·m torque to secure—no specialized equipment needed. The 2-pin connector uses a quick-lock mechanism that plugs into the gearbox harness in 2 seconds, eliminating wiring errors. The switch’s compact dimensions (45mm×28mm×22mm) fit easily in the narrow space of the gearbox valve body. It requires no regular maintenance due to its wear-resistant components, and clear marking (“NC” for normally closed) prevents misinstallation. A single technician can complete the entire replacement process in 20 minutes or less, minimizing truck downtime for fleet operators