Spline Shafts
Spline shafts are mechanical components that consist of a series of ridges or teeth on a drive shaft. They exist to even out the rotation speed of a companion piece and transfer torque in a number of settings. To effectively transfer torque, spline gears rotate and interlock their grooves with the matching grooves of a mating piece. Spline shafts are found in bicycles, some aircraft engines, crankshafts, and vehicles in general. Typically, these gears are made from materials like brass, cast iron, steel, stainless steel, or aluminum. In addition, some spline shafts are hybrid pieces, featuring plastic as well as metal.
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Notable Types of Spline Shafts
Spline shafts are differentiated from one another in a few different ways, the most significant way being the spacing configurations and sizes of their ridges, or broaching teeth.
Common spline shaft types, based on tooth configuration, include:
- Parallel Key Splines
- Serrations
- Involute Splines
- Crowned Splines
- Helical Splines
- Ball Splines
Parallel key splines have parallel and equally spaced grooves that extend both axially and radially. Serrations also have evenly spaced teeth, but instead of being parallel, they form a "V." They are mainly used with small diameter shafts. Next, the evenly spaced teeth of involute splines interlock perfectly with one another when rotating, leading to enough torque to power a machine or vehicle. Involute splines increase strength with their curves, which decrease stress concentrations. Crowned splines are almost identical to involute splines, with equally spaced grooves, except that they have slightly modified male teeth that facilitate misalignments.
Helical splines have evenly spaced teeth that form a helix around the shaft. They have either parallel or involute sides. These can either minimize stress concentrations or allow for rotary or linear motion between parts. The former situation primarily occurs for stationary joints carrying high loads. Finally, ball splines are a bit different from all the others, as the teeth of their outer section are implemented with a ball bearing. This implementation allows for varied amounts of free linear motion, even when the spline shaft is under high torque.
Manufacturing Process of Spline Shafts
Spline shafts are made using a precision machining method known as broaching, which alters surfaces via metal removal. In particular, spline cutting machines are used during this endeavor. Broaching machines and spline cutting machines use metal tools with rows of successively larger teeth, called broaches, to cut holes or create and deepen ridges in plastic, metal, and wood materials.
The broaching process broaches the subject metal removal from two different angles: linear and rotary. During linear broaching, the broach is run linearly against the surface of the workpiece. During rotary broaching, the broach is instead rotated and pressed into the workpiece. In this instance, the goal is to cut an axisymmetric shape into the workpiece. While linear broaching tends to utilize broaching machines, rotary broaching is more likely to use a screw machine or a lathe. However, both methods are rather efficient, requiring only one pass to perform the cut.
In spline shaft production, blind broaches, also called external broaches, are employed to cut furrows along the length of the spline shaft surface. During blind broaching, shapes and intends are knocked into the workpiece without actually penetrating the metal. This aspect of spline shaft production is difficult to execute well, and it can only be successfully carried out by talented and experienced broachers. In addition to spline shafts, blind broaching is generally only used for the creation and perfection of hexagonal, round, and square-cut imprints, holes, and slots. Though it is a difficult and intricate process, blind broaching is an economical way to work on spline shafts, and it gleans results that are uniform and highly repeatable.
Finding the Right Spline Shaft Manufacturer
Manufacturers must choose the number of teeth the spline shafts will have carefully, as this number, along with the preferred pitch diameter, determine spline gear’s pitch. The right spline shaft is essential to the safe and efficient functioning of vehicles both on land and in the sky. To find out more, contact a reputable manufacturer today. Skilled spline shaft manufacturers, such as those listed on this page, will be able to assist a customer determine the best sizes and shapes of their spline shafts. In addition, they will be able to determine and carry out the most advantageous machining methods for any application, whether it is standard or unique.