Project2Example2

Project2Example2 - Nutating Reduction Gear Design Analysis...

Info iconThis preview shows pages 1–5. Sign up to view the full content.

View Full Document Right Arrow Icon
Nutating Reduction Gear Design Analysis Design Project #2 MAE-415.003 By: Lewis Thorp Richard Tilyard Ben Townsend Jennifer West Due: November 15, 2001 “We have neither given nor received any unauthorized assistance on this project.”
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Abstract This report examines a proposed nutating gear design to replace the current double-reduction planetary gear train typically used in cordless screwdrivers. A brief analysis of the current design is presented for understanding. Next, a more thorough analysis of the proposed design is performed in order to determine feasibility. The advantages of the proposed system are reductions in complexity, assembly time, the number of parts, and cost. The current system uses two sets of three planetary gears attached to a single arm, each rotating inside a ring gear to achieve the desired reduction ratio. The nutating system would use less than half as many parts and achieve the same reduction in essentially one step. A force analysis performed on the gear teeth of an equivalent planetary gear design gave stress values within allowable limits. The analysis methods used were those presented in chapters 13 and 14 of Mechanical Engineering Design , by Shigley and Mischke. (Ref.1) Initial analysis of the nutating design does not rule out its feasibility, but to actually recommend the design would require a more thorough analysis, which is beyond the scope of this report. Due to the relatively simple nature of the proposed design, a working model might be the best route for this analysis, especially since the applicability of existing equations to this design is questionable. 2
Background image of page 2
Introduction As rechargeable batteries have continued to improve, cordless drills and screwdrivers have become cheaper to manufacture and more commonplace in the home. To keep costs and weight down, a small motor and large reduction ratio gear train are used in tandem. This design takes the low torque-high speed input from the motor and converts it to a low speed output with a higher useable torque. The typical current design (Figure 1) requires ten separate parts, each with moderate degree of precision in their manufacture. The nutating gear design would significantly reduce the complexity of the reduction gear system, as well as the cost by decreasing the number of parts required for construction. The first task at hand was to fully understand the operation of the current design. This aids in the understanding of exactly how the proposed replacement design must function. 3
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
The above figure gives a good idea of the general construction presently used. However, to get actual dimensions, materials, and ratios, an actual gear train from a Skil -brand cordless screwdriver was obtained and disassembled. Figures 2 and 3 (page 4) are digital photos taken of the disassembled gear set. The number of teeth of each gear from the disassembled screwdriver were counted and found to be 6 teeth on each sun gear, 20 teeth on each planetary gear, and 48 teeth in the ring gear.
Background image of page 4
Image of page 5
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 17

Project2Example2 - Nutating Reduction Gear Design Analysis...

This preview shows document pages 1 - 5. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online