CALIFORNIA STATE POLYTECHNIC UNIVERSITY, POMONA ME 325 – 325 – Machine Design
Design Project Introduction and General Instructions
ME 325L
Power transmission system of a of a ultra‐high‐speed elevator
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CALIFORNIA STATE POLYTECHNIC UNIVERSITY, POMONA ME 325 – Machine Design
Table of Contents
1. Introduction .........................................................................................................................
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2. Design Specifications ....................................................................................................
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2.1 Motor ......................................................................................................................
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2.2 Belts ......................................................................................................................
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2.3 Custom helical gearbox …….....................................................................................
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2.4 Shaft and associated parts ......................................................................................
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2.5 Bearings and associated parts .................................................................................
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3. Schedules of Project Phases ..................................................................................................
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3.1 Phase #1: Team formation 3.2 Phase #2: Problem definition 3.3 Phase #3: Belt drive design 3.4 Phase #4: Custom helical gearbox design 3.5 Phase #5: Shaft/ bearing design 3.6 Phase #6: Final design report 4. Format of Project Deliverables .............................................................................................
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4.1 Manual calculations ...............................................................................................
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4.2 Design drawings ....................................................................................................
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4.3 Unit of measure ....................................................................................
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4.4 Phase submission format ........................................................................................
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4.5 Final project report ................................................................................................
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4.6 Submission material checklist ................................................................................
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5. Project Evaluation ............................................................................................................... 5.1 Progress evaluation 5.2 Design report
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CALIFORNIA STATE POLYTECHNIC UNIVERSITY, POMONA ME 325 – Machine Design
1. Introduction The advent of high‐rise buildings in modern cities requires high‐speed elevator systems to provide quick access within buildings. Buildings over 500m posing an increasing demand for the development of a ultra‐high‐speed elevator. The elevators in the Shanghai Tower can carry 80 people at once and travel at more than 37 mph (60 km/h or 1,000 meters a minute) from http://www.gizmag.com/mitsubishi‐ultra‐high‐speed‐elevator/21324/ .
Figure 1 – The 2,073‐ft (632‐meter) Shanghai Tower (the tall one) with ultra‐high‐speed elevators
Elevator systems are typical examples for complex mechanical systems and may consist of three subsystems (Fig. 2) – drive, travel, and control systems. The team project will design critical components in drive and travel systems in a ultra‐high‐speed elevator.
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CALIFORNIA STATE POLYTECHNIC UNIVERSITY, POMONA ME 325 – Machine Design
Figure 2 – A typical elevator system and a schematic of an elevator sub‐system (from http://www.srl.gatech.edu/education/ME6105/Projects/Sp08/YZZY/index )
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CALIFORNIA STATE POLYTECHNIC UNIVERSITY, POMONA ME 325 – Machine Design
2. Design Specifications Please note that the specifications stated below may be subjected to change and revisions/details will be announced as needed..
2.1 Motor
Output power requirements shown in the table below.
Table 1 – http://www.mitsubishielectric.com/company/rd/advance/pdf/vol88/vol88.pdf
Figure 3 – Car speed and acceleration profile unter full load (from http://www.srl.gatech.edu/education/ME6105/Projects/Sp08/YZZY/index )
2.2 Belt Drive (V‐belt)
The belt drive should have an estimated life of 10 years.
2.3 Custom Planetary Gearbox
The custom planetary gearbox may have multiple stage reduction. 5
CALIFORNIA STATE POLYTECHNIC UNIVERSITY, POMONA ME 325 – Machine Design
The gearbox is to have an estimated life of at least 10 years.
Gear material: Through‐hardened steels (maximum BHN=360)
Select a lubricant from SAE oils and conduct lubrication analysis.
2.4 Shafts and Associated Parts In addition to the input and output shafts, there are intermediate shafts to be designed in the custom gearbox. The shafts have solid circular cross‐sections and supported by bearings.
Shaft material: AISI 4340
2.5 Bearings and Associated Parts
Select bearings from the SKF online catalog, http://www.skf.com.
The same lubricant in the custom gearbox is used.
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CALIFORNIA STATE POLYTECHNIC UNIVERSITY, POMONA ME 325 – Machine Design
3. Schedules of Project Phases 3.1 Phase #1: Team formation In this phase, you will form a project team of four members and prepare a team contract. The design project is demanding and it is important that your team functions effectively. You will prepare a 3‐hole binder with dividers and write a first report on your team member’s names, pitctures, Bronco ID and e‐ mail addresses. Due: First week (Marks: 10/ 100)
3.2 Phase #2: Problem definition You will conduct literature survey for elevator safety regulations and mechanical analysis of the elevator system and specify the key design parameters 1.
Required HP and the reduction ratio
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Wire rope
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Counterweight
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Sheaves
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Electric motor
Due: TBA (Marks: 20/ 100)
3.3 Phase #3: Belt drive design You will design v‐belt drives. Select appropriate belt section, belt length, and sheaves from the Gates catalogs. Due: TBA (Marks: 10/ 100)
3.4 Phase #4: Custom helical planetary gearbox design Assume a multi‐stage planetary gear train is used for speed reduction. Based on calculated gear forces conduct shaft design analysis. Due: TBA (Marks: 20/ 100)
3.5 Phase #4: Shaft/ bearing design And, you will design/ select shafts, journal bearings AND rolling‐element bearings from the SKF on‐line catalogue bearings. Due: TBA (Marks: 20/ 100) 7
CALIFORNIA STATE POLYTECHNIC UNIVERSITY, POMONA ME 325 – Machine Design
3.6 Phase #6: Final design report Create a written project report with the recommended format in Sec. 4.3. Due: TBA (Marks: 20/ 100)
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CALIFORNIA STATE POLYTECHNIC UNIVERSITY, POMONA ME 325 – Machine Design
4. Format of Project Deliverables 4.1 Manual calculations You are requested to submit manual calculations as needed and to ensure that these are well‐ presented. The purpose of engineering design calculations is not only to verify that a design is acceptable but also to provide clear documentation so that an engineer, not familiar with this project, could reproduce and verify your design calculations. Take note of the following in preparing your calculations:
Provide clear headings.
Summarize the purpose of each calculation and subsequent results.
Clearly state and discuss the validity of all key assumptions.
Provide all key relations and provide references unless the relations are commonplace (e.g. “F = m × a” need not be referenced).
Define all notations and provide sketches as needed to ensure the reader knows unequivocally what you mean and that your notation is clear.
Provide free body diagrams and schematics.
Highlight key results.
NOTE THAT POORLY PRESENTED CALCULATIONS WILL NOT BE GRADED!!
4.2 Design drawings For each phase (except phase 1), the team will develop an assembly drawing and part drawings which illustrate the key aspects of the design. It is recommended that drawings be made using SolidWork. Label all key components using a part number (in a circle) connected by a leader to the part. Include a bill of materials in the top right hand corner, or attached to the assembly drawing which provides the component names, part numbers, materials, and any other comments. Also provide the part drawings for each component.
4.3 Units of measure: All calculations and drawings are to be done in a single unit system, either US or metric units. 9
CALIFORNIA STATE POLYTECHNIC UNIVERSITY, POMONA ME 325 – Machine Design
4.4 Phase submission format Prepare a three‐hole binder with dividers for each team. Each of the submissions that your team will produce should be concise, well organized and easy to follow in the project binder. Always provide an executive summary for each phase. Include all the relevant materials such as hand/ computer calculations, drawings, catalog printouts, etc. The submission that your team makes at the end of each phase (except phase I) MUST comply with the following format:
An executive summary for each phase
Sections separated with tabs.
All pages should be numbered.
All drawings should be folded and placed in a plastic envelope. The envelope is included in the report as its own section.
Hardcopies of all the calculations using MDT4
Catalog prinouts for your design selection
4.5 Final project report Create a written project report (Word document) with the recommended format below. 1. TITLE PAGE 2. EXECUTIVE SUMMARY (no more than 6 to 8 lines)
‐ Objectives of the analysis ‐ Main results and conclusion 3. INTRODUCTION
‐ Purpose and Scope ‐ Theory and its relation to problem at hand 4. DESIGN ANALYSIS PROCEDURES
‐ Overall design rationale ‐ Major assumptions in each analysis ‐ Design schematics 5. RESULTS
‐ Quantitative results ‐ Presentation of results: Tables & graphs 10
CALIFORNIA STATE POLYTECHNIC UNIVERSITY, POMONA ME 325 – Machine Design
‐ Discussion of results (important!!) 6. SUMMARY, CONCLUSIONS AND RECOMMENDATIONS
‐ Summarize purpose, scope and results ‐ State conclusions ‐ Make appropriate recommendations
4.6 Submission material checklist The follwing materails are to be submitted due at the last day of the class.
Project binder (This will not be returned so make a duplicate for your own record)
A CD containing PowerPoint presentation file, a written project report and all the computer files (CAD, MDT, etc) from all the members.
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CALIFORNIA STATE POLYTECHNIC UNIVERSITY, POMONA ME 325 – Machine Design
5. Project Evaluation 5.1 Progress evaluation Each phase of the project is assigned based on the amount of effort and complexity (See Section 3.0). NOTE THAT TME IS ESSENCE IN SUCCESSFUL COMPLETION OF THE PROJECT. LATE SUBMISSION WILL RESULTS IN REDUCED SCORES.
5.2 Design report The grading criteria for the final design report is as follows.
Report organization and format
Overall design
Design rationale and justification
Design analysis for optimization
Design suggestion and recommendations
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