Disengaging Gear Unit Cam Assembly Preload and Sealing
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Solution Overview
Problem
Disengagable reduction gearboxes face challenges in maintaining precise pre-loading of thrust bearings during manufacturing, leading to operational issues, and existing sealing mechanisms are prone to leaks and contamination, making the process costly and time-consuming.
Innovation Solution
The design incorporates a cam assembly with a threaded bore and adjustable bearing assembly that allows pre-loading before assembly, and a sealing mechanism using o-rings and an end collar to ensure a tight seal without precise machining of the gearbox case, reducing the risk of leaks and contamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If thrust bearings are pre-loaded during assembly, then operational performance is improved, but manufacturing precision is difficult to maintain
Solution Approach 1:
The bearing pre-load is applied and adjusted before the bearing assembly is permanently installed in the gearbox. The adjustable bearing assembly allows pre-loading to be performed at a convenient stage in the manufacturing process, and then the assembly is locked in place to maintain that pre-load setting throughout subsequent assembly and operation.
Solution Approach 2:
The bearing assembly is designed to be adjustable rather than fixed, allowing the pre-load to be set and then locked. This dynamic adjustment capability enables precise pre-load application that would be difficult to achieve through rigid fixed-position assembly methods.
2Reliability
If precise machining is performed on gearbox case seats, then sealing performance is improved, but manufacturing cost and time increase
Solution Approach 1:
An intermediary sealing mechanism is introduced between the bearing assembly and the gearbox housing. This sealing interface is designed to be less sensitive to machining variations in the housing, allowing adequate sealing performance to be achieved without requiring extremely precise machining of the case seats.
Solution Approach 2:
The sealing mechanism utilizes flexible sealing elements (such as O-rings or similar flexible seals) that can accommodate minor variations in the housing bore dimensions and surface flatness. This flexibility compensates for machining tolerances and achieves reliable sealing without requiring ultra-precise machining.
Data Source
AI summary
Reduction gear units are provided comprising a gearbox, a cam assembly, a bearing assembly, a first gear and a second gear. The first and second gears may engage one another and translate rotating movement from one axis to an axis perpendicular thereto. The second gear is disengagable from the first gear by action of the cam assembly, which is adapted to disengage the second gear from the first gear through eccentric rotation of the cam assembly. In one embodiment, a bearing assembly carried by the cam assembly is preloaded. The cam assembly is disposed so that the preloaded can be maintained during manufacture of the gearbox. In another embodiment, the gearbox case and cam assembly are disposed so as to minimize internal leakage from the case and enhance sealing of the gearbox.