“When bearings aren’t strong enough, they wear out, causing the shaft to shift and the seal to leak. An OHLA provides bearing support to prevent the shaft from shifting and cutting into the seal,” explained Mark Treise, applications engineer at Zero-Max. “It also acts as a contamination barrier, protecting the hydraulic motor or pump from external elements and safeguarding the hydraulic motor seals from debris, chemicals, water, or sand. It’s a replaceable or repairable unit, but the main advantage is having a separate component that avoids the need to open up the hydraulic system.”

Zero-Max has been producing OHLAs for decades, primarily for hydraulic applications, but the company is now exploring opportunities in other fields.
“Our overhung load adapters were initially used on pulleys, but they soon found widespread use on cooling fans or radiator fans in highway equipment, fracking trucks, and mining machinery, which deal with axial loads. Now, we’re exploring new applications and developments in electrification,” said Brian Mishuk, VP of sales and marketing at Zero-Max.

One innovative example is a grinding application, currently in the prototype stage, where a grinding stone is directly attached to the output shaft of the OHLA, which, in turn, is connected to an electric motor. The OHLA manages the axial and radial loads generated by mobile grinding operations and acts as a contamination barrier to keep grinding dust from entering, thus prolonging the system’s lifespan.

“It’s a harsh environment with abrasive grinding dust getting everywhere, so we added unique sealing features,” said Mark Treise. “There are multiple levels of sealing and purging, so if debris bypasses the first seal, we can regrease and purge it before it penetrates deeper into the unit.”

Zero-Max’s standard OHLA products are designed according to SAE specifications for hydraulic pumps and motors. However, electric motors often have non-SAE mounting features, NEMA standards, or other unique variations. As a result, Zero-Max customizes about 75% of the OHLAs they manufacture.

Additionally, OHLAs can serve as contamination barriers for electric power takeoffs (ePTOs) that power auxiliary equipment on mobile machinery.

“If a hydraulic pump seal fails, high-pressure oil could flood the engine's crankcase and seize an internal combustion engine. The same risk applies to electric motors; hydraulic oil under pressure could damage the motor and even pose a fire hazard,” Treise explained. “The overhung load adapter acts as a contamination barrier, separating the hydraulic motor from the PTO or electric motor.”

Treise also incorporates weep holes into the units to detect leaks and divert fluid away from the PTO. He can add a low-pressure check valve to provide an alternate oil exit path, enhancing the unit’s safety and reliability.

Over the past year, Zero-Max has seen a growing number of inquiries for electrification applications, particularly for use in mining and construction equipment. As more industries shift towards electrification, the company anticipates even more opportunities for its overhung load adapters (OHLAs).

“What’s exciting for us is that the OHLA is a proven, field-tested product,” said Brian Mishuk, VP of sales and marketing at Zero-Max. “We’ve continually evolved our product line, and it’s now quite extensive, always finding new applications. With electrification, we sometimes encounter familiar components, like radiator fans, but the mounting requirements change. While this necessitates significant customization, our core technology has been effectively addressing load challenges for years.”