Pulley hubs are often formed by pressing a powder metal alloy into a mold. The pressured mixture is then sintered to form a pulley hub. This process produces a high-strength component that can be readily reproduced. It also offers numerous advantages over other manufacturing techniques. These include high material flexibility, a high degree of customization, and repetitive accuracy. In addition, lubricants may be blended into the powder blending process to enhance its properties.

A pulley hub is made up of a tubular body and a pair of pulling flanges. The pulling flanges are integrally formed with the tubular body. Typically, they extend diametrically opposite directions. They can be either outwardly or radially extending.

Two-piece pulley hubs are more expensive to produce than single-piece hubs. However, they provide a satisfactory solution to the problem. Ideally, each member is formed in green compact form in a pair of molds. Once formed, the components are pressure-fitted into one another to form an integrated hub. This method eliminates the need for complicated machining procedures and provides a durable, low-cost, and efficient product.

Generally, the first member has a cylindrical body. The second member has an annular cavity. When the members are joined, the cylindrical outer surface of the second member is formed to form an annular groove with the flange surface of the first member. Alternatively, the two members may be made from different powder metal mixtures. This is determined by the application. Regardless of the type of powder metal used, the resultant metallurgical blend may be brazed or welded to the tubular body. Brazing or welding may be a more economical process depending on the composition of the tubular body.

Among the features of the improved pulley hub construction are a radially extending axial flange, a cylindrical surface, and an annular shoulder. These features are achieved by aligning the annular flange of the pulley cup with the annular shoulder of the second tubular member. As a result, the radially extending flange of the pulley cup is received within the annular shoulder, thereby providing a zone in which the flange can be welded to the hub. Increasing the thickness of the second member may also allow the internal bore diameters to be changed.

For example, the flange flange of the pulley cup can be welded to the conical wall of the tubular body. The flange can then be secured to the cup by simple circular welding procedure. If the annular groove is too narrow, a ring of metal can be used to form the annular flange. Another example is the V-grooves 28 of the pulley cup which are rolled into the axially extending sidewall of the pulley cup.

An integral hub can be produced from a powder metal mixture by forming a pair of tubular members and telescopically joining them. Each member is then placed in a sintering furnace and heated at a predetermined temperature for a period of time to achieve a homogeneous body.