What Is a Puller?
A puller, a tool designed to remove bearings, gears, and other press-fitted parts from machines and automobiles, is essential for the precise application of force. The term “puller” aptly describes its function of pulling out components.
Various types of pullers exist, each optimized for different parts and disassembly locations, as well as general-purpose pullers adaptable to multiple settings.
Uses of Pullers
Pullers are primarily employed in the maintenance and disassembly of machines and automobiles. Gear pullers, for example, are used in transmission disassembly to extract gears from shafts.
Bearing pullers are specifically designed to remove bearings. Pullers with unique jaw shapes are used for pilot bearings and hub bearings, which are challenging to remove with standard pullers.
Specialized pullers are also available for components like motorcycle flywheels.
Principle of Pullers
A standard puller consists of jaws for gripping the part and a bolt for applying pulling force. The jaws latch onto the part, and when the bolt, fixed to the base material, is tightened, it applies a pulling load, extracting the part. This force is primarily generated from the axial force of tightening the bolt, though some pullers utilize hydraulic force.
The correct jaw type is selected based on the part’s shape and size. If the gap between the jaws is narrow, thinner jaws are used. However, to compensate for reduced strength, the number of jaws may be increased or designed to grip the entire circumference of the part.
When removing a bearing, the axial force during pulling can cause indentations in the raceway of the rolling elements, rendering the bearing non-reusable.