Transmission Bearing Clamp Arrangement Without Threads or Slots
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Solution Overview
Problem
Existing bearing arrangements for rotary drives in aircraft flight control surface actuators require deformation of components like cup washers, leading to increased costs and stress concentration due to threads and slots, necessitating larger shafts and frequent replacements.
Innovation Solution
A bearing arrangement utilizing a clamp member with a tapered portion on a rotary member, which axially fixes the bearing without threads or slots, allowing for re-use and reducing stress concentration, using a bearing cap for fixation to a static structure and employing a splined or forked end for connection to drive and driven devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a keeper nut and cup washer arrangement is used to axially fix the bearing, then the bearing can be retained in its axial position, but the cup washer must be replaced after deformation and the shafting requires stress concentration management
Solution Approach 1:
The patent extracts the bearing retention function from the traditional keeper nut and cup washer system. The deformable bearing outer race itself performs the retention function by deforming to engage with the groove in the bearing retainer, eliminating the need for separate cup washers and reducing manufacturing complexity
Solution Approach 2:
The patent combines the bearing outer race with the retention mechanism. The outer race is designed to be deformable and directly engages with the groove in the bearing retainer, merging the support function and retention function into a single integrated component
2Reliability
If threads and slots are defined in the shafting for bearing fixation, then the bearing can be axially fixed, but stress concentration occurs requiring larger shafting dimensions
Solution Approach 1:
The patent removes the threads and slots from the shafting design. Instead of cutting stress-concentrating features into the shaft, the retention mechanism uses a groove in the bearing retainer and deformable bearing outer race, eliminating the need for threaded holes and slot cuts in the shafting itself
Solution Approach 2:
The patent concentrates the deformation and stress in the bearing outer race material rather than in the shafting. The local deformable property of the bearing outer race allows it to engage with the groove without requiring stress-concentrating features in the critical shafting path
3Ease of manufacture
If a deformable bearing outer race is used to engage with the bearing retainer groove, then the bearing can be retained without single-use components, but the bearing structure must accommodate deformation
Solution Approach 1:
The bearing outer race serves dual functions: supporting the rotary member and performing self-retention by deforming to engage with the groove. The bearing structure is self-sufficient, eliminating the need for separate single-use retention components like cup washers
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution enables axial fixation of bearings without single-use components, reduces stress concentration, extends service life, and simplifies fabrication by eliminating the need for threads and slots, resulting in lighter and more cost-effective rotating components.
Implementation Method 1
The clamp member is seated on the tapered portion of the rotary member and exerts an axial force component on the bearing
Data Source
Figure 1
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AI summary
A bearing arrangement includes a rotary member (102), a bearing (104), and a clamp member (106). The rotary member (102) is arranged along a rotation axis and has a collar portion (110), the collar portion extending radially outward from the rotary member. The bearing extends about the rotary member and axially abuts the collar portion, the bearing arranged to support the rotary member for rotation about the rotation axis. The clamp member is seated on the rotary member and on a side of the bearing opposite the collar portion, the clamp member urging the bearing axially toward the collar portion to axially fix the bearing relative to the rotary member. Transmission assemblies and methods of making bearing arrangements are also described.