Clever Bearing Design Reduces Drive Costs

The ability to fold as many as 18,000 sheets of paper per hour meant an automated machine relied on adjustable surfaces driven by a stepper motor. Space availability and cost constraints however require a motor with low torque output; therefore the motor shaft support consequently demands the use of needle roller bearings. Spyrflo special low-friction needle bearings were the design secret to a new, fully automated paper-folding machine. Mounted directly into the machine's sheet metal chassis, the self-aligning, self-clinching roller bearings not only eliminate the need for rigid, accurately machined mounting blocks they allowed use of less-expensive drive motors. On the new design conventional plain bearings the kind typically used in the past did not prove suitable because they have some shaft resistance to turning and plain bearings typically overloaded the new drive. While low-friction needle bearings worked better, the machine's thin sheet metal framework also demanded a self-aligning bearing to compensate for dynamic misalignment generated by the drive. Self-aligning ball races were considered but these must be pressed into a machined housing for mounting in the sheet metal framing. This additional step added significant cost and created space problems. The simple solution was the easy-to-install bearing unit called ReadyMount the result of a partnership between Spyraflo and INA. The patented design uses a Spyraflo full-contact, self-aligning insert to support an INA needle roller bearing. This assembly, in turn, is housed in a Spyraflo retainer, permitting secure installation into sheet metal. Requiring only a simple press operation, the installation process facilitates the cold flow of material around the retainer, ensuring a solid assembly with minimal cost. Additional benefits include reduced clearances, and lower operating costs as drive maintenance is reduced or in some cases eliminated altogether. Although the ReadyMount unit costs more than a standard plain bearing, the overall system savings are achieved through the use of minimum thickness sheet metal framework, reduced assembly time and machining costs and the fact no bearing mounting blocks are needed. Micromech is the UK and Ireland distributor for these clever bearings.