Universal coupling is a kind of coupling, divided into two categories: precision universal coupling and high torque universal coupling. It is a movable rigid coupling used on two intersecting shafts.The angle between the two axes can reach 45°, which is widely used in machine tools, automobiles, precision machinery and heavy machinery.The universal coupling is formed by connecting two fork-shaped parts and a cross-shaped part.When the driving shaft rotates at a constant angular velocity ω 1, if the angle between the two axes is α, the angular velocity ω 2 of the driven shaft will periodically change within the range of ω 1cosα ≤ω 2≤ω 1/cosα, causing additional Dynamic load.Therefore, a single universal coupling is not suitable for the connection with high speed and large angle between the two axes.In order to overcome the above shortcomings, a double universal coupling can be used, that is, an intermediate shaft is used to connect two universal couplings. When installing, the axis angles of the main and driven shafts and the intermediate shaft are equal, and the two The fork-shaped parts at the end are in the same plane, so that the angular velocity of the driving shaft and the driven shaft can be equal at any time.The instantaneous speed of the two shafts can be approximately equal by using the ball-cage universal coupling and the ball-groove universal coupling. SWC type and SWP type cross shaft universal coupling can be widely used in metallurgy, lifting, engineering transportation, mining, petroleum, shipbuilding, coal, rubber, papermaking