The shaft-hub connection is a shaft part connecting the shaft-hub and the shaft, such as gears and pulleys. The connection positions and fixes the rotating part on the shaft in order to transmit motion and power. The connection methods of the trailer axle hub include key connection, spline connection, forming connection, expansion sleeve connection, pin connection, set screw connection, interference connection, etc. Some connection methods are only used for trailer axle stubs and hubs connection, and some connection methods can be used as other connect. Keys and splines are the most common shaft-hub connections.

Ⅰ. Trailer axle hub key connection

The key is a standard part, which is usually used to connect the shaft and the rotating parts and swing parts on the shaft. It acts as a circumferential fixed part to transmit rotary motion and torque. The wedge key can also play a one-way axial fixed part. The guide key, feather key and spline can also be used as a guide device for moving on the shaft. According to the structural form of the key, the key connection can be divided into several types such as flat key connection, semicircular key connection, wedge key connection and tangential key connection.

1. Flat key connection: The two sides of the flat key are working surfaces and are used to transmit torque. There is a gap between the top of the key and the bottom of the hub groove, which is the non-working surface. The main dimensions are key length, key width and key height.

2. Semi-circle key connection: it transmits torque by the two sides of the key, so its working surface is two sides. The upper keyway is machined with a disc milling cutter with the same size as the half-round key, so the key can swing around its geometric center in the groove to adapt to the inclination of the hub groove of the trailer fittings due to machining errors.

3. Wedge key connection: The upper and lower surfaces of the key are working surfaces. The upper surface of the key and the bottom surface of the hub keyway have a slope of 1:100. After assembly, the key is wedged tightly in the keyway of the trailer accessory shaft and the types of trailer hubs to work. The surface generates a large preload.

4. Tangential key connection: It consists of two ordinary wedge keys. Its upper and lower surfaces (narrow surfaces) are working surfaces, one of which is in the plane passing through the axis. The pressure on the working surface acts in the tangential direction of the shaft and can transmit a large torque. A tangential key can only transmit torque in one direction. When transmitting torque in two directions, two keys with an angle of 120° to 130° must be used. It is used for occasions where the load is large and the alignment requirements are not strict. Because the keyway weakens the shaft greatly, it is often used on shafts with a diameter greater than 100mm. Such as the connection of large pulleys and flywheels, reels and gears of large mining winches and shafts.

Ⅱ. Spline connection of trailer axle hub

The spline connection consists of internal splines and external splines. The inner and outer splines are multi-tooth parts, the splines on the inner cylindrical surface are internal splines, and the splines on the outer cylindrical surface are external splines. Obviously, the spline connection is a numerical development of the flat key connection. The centering method of the rectangular spline is the small diameter centering, that is, the small diameter of the external spline and the internal spline is the mating surface. It is characterized by high centering accuracy, good centering stability, and can eliminate the deformation caused by heat treatment by grinding. The rectangular spline connection is the most widely used spline connection. Wide range of applications. Such as aircraft engines, automobiles, gas turbines, machine tools, construction machinery, tractors, agricultural machinery and general mechanical transmissions, etc.

Ⅲ. Trailer axle hub pin connection

The pin connection is generally used to transmit a small load or as a safety device; another function is to play a positioning role. Often used in pairs with hole bolts and hex slotted nuts, insert the pin into the bolt hole and the nut slot to prevent the nut from loosening. Pins are divided into three categories: cylindrical pins, tapered pins and special-shaped pins.

Ⅳ. Keyless connection of trailer axle hub

Any custom trailer accessories connection without keys, splines or pins in the trailer axle-hub connection is collectively referred to as a keyless connection. In the keyless connection, we introduce two commonly used profile connections and interference fit connections.

1. Surface connection

It is a connection formed by using a shaft with a non-circular section and a hub hole of a corresponding shape of the part. As a connection method in mechanical transmission, compared with the traditional key connection, the profile connection has higher connection strength and no stress concentration. It can transmit large torque and high efficiency, and can also withstand impact loads, and for some large mechanical equipment, it is easy to disassemble and maintain.

2. Interference fit connection

It is a connection formed by an interference fit between two connected parts, and is often used for the connection of shafts and parts with hubs.