Hengguan Bearing Successfully Repairs Slewing Bearing for Raise Boring Rig; Expert Technical Solutions Overcome Challenges in Deep-Well Operating Conditions

Recently, Luoyang Hengguan Bearing Technology Co., Ltd. (hereinafter referred to as "Hengguan Bearing") received an urgent request for assistance from a user of a raise-boring machine. The client reported that their machine had suddenly broken down during operation, with its core component—the Slewing Bearing—seizing up and becoming completely immobile. To avoid any delays to their project schedule, the client removed the damaged slewing bearing and shipped it to our factory, seeking an urgent repair.

Used bearings

Identifying the root cause: a combination of specific operating conditions and inadequate lubrication

Upon receiving the worn-out slewing bearing at the facility, our technical team conducted a thorough inspection and identified it as a product manufactured by a company in Shandong—one that had been in service for less than a year. Why did it fail so quickly? Through consultation and investigation, we discovered the root cause: the specific operating conditions. While most slewing bearings are designed for horizontal installation, the bearing in this raise-boring machine was installed vertically. Furthermore, it operated deep underground, where it was exposed to significant amounts of silt and sediment. Compounding the issue was inadequate lubrication, which allowed debris to infiltrate the unit, ultimately causing the internal components to seize up completely due to severe rust.

The faulty slewing bearing, which has an outer diameter of nearly 2,500 mm, features an external-Geared, crossed-roller design. It is equipped with dual-layer seals both internally and on the outer ring, making the disassembly process exceptionally challenging. Nevertheless, committed to our responsibility toward the client, the technical team at Hengguan explored various methods and ultimately succeeded in dismantling the unit.

The Right Solution: Retain the Outer Ring, Custom-Make a New Inner Ring

Upon disassembly, we discovered severe damage to the inner raceway, characterized by extensive material spalling, rendering the component unfit for further use. In consultation with the client—and adhering to our core principle of "product quality above all else"—we decided to retain the existing outer ring while sourcing a new inner ring to complete the assembly.

A simple restoration would not have prevented the recurrence of the same failure. Given the challenging operating environment—characterized by high levels of sediment and difficult lubrication—our technical team at Hengguan implemented targeted modifications to the internal structure of the slewing bearing:
First, we adjusted the roller configuration and replaced the original nylon spacers with nylon rods. This modification increases the grease capacity within the raceway cavity, enhancing lubrication and lowering operating temperatures.
Second, we added a grease inspection port. This allows the client to monitor grease levels and the presence of contaminants, facilitating timely replenishment of lubricant and the removal of debris from the raceway—effectively eliminating the root cause of potential seizures due to a lack of lubrication.

On-Time Delivery: Professionalism Earns Client Praise

Following 45 days of systematic production and processing, the repaired large-diameter slewing bearing was delivered to the client on schedule. The component has since been successfully installed and commissioned, allowing the raise-boring rig to return to operation. The client expressed high appreciation for the strong support provided by Hengguan Bearing, as well as for the company’s professional and dedicated work ethic.

As a manufacturer with extensive, long-term experience in the slewing bearing industry, Luoyang Hengguan Bearing offers not only the production and customization of various standard and non-standard slewing bearings, but also professional repair and technical retrofitting solutions tailored for demanding operating conditions. Regardless of the size or structural complexity of your slewing bearing, we are committed to applying our technical expertise and a strong sense of responsibility to solve your practical challenges, ensuring the trouble-free operation of your equipment.

(Keywords: Slewing bearing, raise-boring rig slewing bearing, crossed-roller slewing bearing, slewing bearing repair, slewing bearing manufacturer)