Abstract: A vehicle-mounted electric oil-free air compressor, including a motor, a box body, a piston, and a flywheel shaft. The motor is fixed on the box body, a cylinder cover is at the top of the box body, a main shaft of the motor includes a coupling driving end, the flywheel shaft is driven by an elastic body to rotate. The piston includes a primary intake valve piece and a primary exhaust valve piece, the box body is provided with a secondary cavity, a secondary exhaust valve piece is provided at a vent hole on one side of the cavity, and the primary exhaust valve piece is also a secondary intake valve piece of the compressor, increasing the exhaust pressure. When the piston reciprocates, the stress is balanced and the vibration is small, and with the assistance of a high-efficiency flywheel, the operation of the air compressor is stable.

Abstract: A quick joint in a hydraulic pipeline, more particularly, a quick pipeline joint applied to a hydraulic system, where frequent disconnection or connection of liquid pipelines is required. In one embodiment, the quick joint in the hydraulic pipeline includes an outer joint and an inner joint. The outer joint includes an oil pipe joint, O-rings, a block, a spring, a valve rod, a plunger, a joint sleeve and other parts. The inner joint includes a plurality of O-rings, a spring seat, a joint sleeve, a spring, an oil pipe joint and other parts. The outer joint and the inner joint can be connected or disconnected easily through insertion and pull-out of a circlip.