A spline connection consists of an internal spline and an external spline. Both the inner and outer splines are multi-tooth parts, the splines on the surface of the inner cylinder are inner splines, and the splines on the surface of the outer cylinder are outer splines. Obviously, the spline connection is the numerical development of the flat key connection.
1. Classification of splines
The types of spline shafts that are common on the market are roughly divided into three types. One is the rectangular spline shaft, which is widely used, such as machine tools, automobiles, aircrafts and other machinery; the other is the involute spline shaft. Shafts are mainly used on links that require high centering accuracy, large loads, and large sizes; the third type is triangular splines, which are used for connection of thin-walled parts.
2. The use characteristics of splines
Features of use: Due to the difference in structure and manufacturing process, compared with the flat key connection, the spline connection has the following characteristics in terms of strength, technology and use:
Because more teeth and grooves are directly and evenly made on the shaft and the hub hole, the coupling force is relatively uniform;
Because the groove is shallow, the stress concentration at the root of the tooth is small, and the strength of the shaft and the hub is less weakened; the number of teeth is large, and the total contact area is large, so it can withstand large loads;
The parts on the shaft and the shaft have good alignment, which is very important for high-speed and precision machines; good guidance, which is very important for dynamic connections; grinding methods can be used to improve machining accuracy and connection quality;
The manufacturing process is more complicated, sometimes requires special equipment, and the cost is higher;
Applicable occasions: connections that require high centering accuracy, large transmission torque or frequent slippage. Most of the spline shafts seen on the market are made of 40Cr material, the surface hardness of the material is required to be HRC45--50, and heat treatment is required.
3. Ball spline The ball spline uses the balls installed in the outer cylinder of the spline shaft to smooth the transmission torque of the rolling machine at the same time in the precision-ground rolling groove. It adopts a unique contact point design and has greater contact Angle (40°), in addition to high sensitivity, can greatly improve the ability to control, suitable for environments with excessive vibration and shock loads, high positioning accuracy requirements, and high-speed motion performance, and can also be used in such environments play an effective role. At the same time, even if it is used instead of the linear ball bushing, the rated load of the ball spline is more than ten times that of the linear rail bushing under the same shaft diameter, so it can make the world very compact, even under the cantilever load, moment It is safe to use and has high durability even under the conditions of other effects.
The advantages of the ball spline in detail
Large load capacity: The rolling groove of the ball is formed by precision grinding, and adopts Goethe-type 40° angle contact. Because of the large contact angle, it has a large load capacity in both radial and torque directions.
Zero clearance in the direction of rotation: By adopting 2-4 opposite rows of ball rows with a contact angle of 40°, the spline is combined with the outer cylinder of the spline, and the clearance in the direction of rotation can be zero by adjusting the preloading method.
High sensitivity: Due to the special design of the contact point of the steel ball, in addition to high rigidity, it is more sensitive and can reduce the waste of capacity.
High rigidity: Due to the large contact angle, it has high rigidity, and appropriate preload can be applied depending on the situation, so high torque rigidity and moment rigidity can be obtained.
Simple assembly: Due to the special design, the outer cylinder of the spline can be separated from the spline shaft in time, and the steel ball will not fall off. Therefore, assembly, maintenance and inspection are all easy to carry out.
