RC08Drive Module

As part of the Robocup 2008 Mechanical, the Drive Module packages the gears, wheel, and motor into an useful robot maneuvering tool.

2008 RoboJackets RoboCup Drive Module

Assembly Structure

Parts List

1. 1 - Omni Wheel (RC-2008-02-00)
2. 1 - Maxon Brushless Drive Motor (RC-2008-03-01)
3. 1 - Drive Module Plate (inner) (RC-2008-03-02)
4. 1 - Drive Module Plate (outer) (RC-2008-03-03)
5. 1 - Base Attachment (RC-2008-03-07)
6. 1 - Output Shaft (RC-2008-03-06)
7. 3 - 1/2" Long Hex Standoffs (RC-2008-03-11)
8. 1 - Input Gear (RC-2008-03-05)
9. 1 - Output Gear (RC-2008-03-04)
10. 2 - 1/4" Ball Bearings (RC-2008-03-08)
11. 2 - 1/4" E-Clips (RC-2008-03-09)
12. 4 - 8-32 Socket Cap Screws Counter Sunk (RC-2008-03-12)
13. 3 - 8-32 3/8" Long (RC-2008-03-13)
14. 1 - Washer (RC-2008-03-10)
15. 3 - M3 Machine Screws (RC-2008-03-14)
16. 1 - 5/16" E-Clips (RC-2008-03-15)

Instructions

1. Press bearings in to plates so that flange is always on the the with out counter sinks.
2. Using RC-2008-03-13 and RC-2008-03-11 attach the base attachment to the inner drive module plate (inner plate).
3. Using RC-2008-03-12 fasten top stand off (RC-2008-03-11) to the inner plate.
4. Mount motor with RC-2008-03-14. Position motor so that the wiring is coming out of the smaller removed corner.
5. Place input gear on motor such that the hub is closer to the motor.
6. Put output shaft in outer plate's bearing with hex side on the side with counter sinks.
7. Place an e-clip on the groove outside the outer plate and immediately inside the outer plate.
8. Put output gear on the output shaft (now in the inner plate) with the hub facing away from the outer plate.
9. Add an e-clip to the last groove.
10. Align the outer plate and then fasten it to the standoffs (already on inner plate) using RC-2008-03-12.
11. Put omni wheel on output shaft with screws facing out.
12. Using the washer (RC-2008-03-10) and 8-32 fasten the omni wheel in place.

Parts & Components

Bearings

1/4" Shaft Diameter

Vendor - Grainger

Part No. - 1ZEJ7

Cost - $5.59 Each

Description - Miniature Ball Bearing, Open, Flanged, Bore Dia 0.2500 In, Outside Dia 0.5000 In, Width 0.1250 In, Flange Dia 0.5470 In, Flange Thickness 0.0230 In, ABEC Level 3

Info - Web Link

Gears

Input

Vendor - SDP/SI

Part No. - S1063Z-072A020

Cost - $9.83 ($6.76 in bulk)

Description - 0.2778" Pitch Dia, 0.125" Face Width, 0.125" Bore (must bore out to 4mm)

Note - Al 2024

Input (Back Up Supplier)

Vendor - WM BERG

Part No. - P72S10-20

Cost - $13.25 Each (Same for bulk)

Description -

Note - Stainless 303

Output

Vendor - SDP/SI

Part No. - S1066Z-072S100

Cost - $17.72 ($13.02 in bulk)

Description - 1.3889" Pitch Dia, 0.125" Face Width, 0.25" Bore

Note - Stainless 303

Output (Back Up Supplier)

Vendor - WM BERG

Part No. - P72S28-100

Cost - Each

Description -

Note - Stainless 303 & thicker (7/16)"

Stock

5/16" Hex Bar Stock

Vendor - McMaster-Carr

Part No. - 6512K14

Cost - $5.85 Each

Description - 1018 Carbon Steel Hexagonal Bar 5/16" Hex Size, 6' Length

Al Plate 1/8"

Vendor - McMaster-Carr

Part No. - 89015K18

Cost - $26.06

Description - Alloy 6061 Aluminum Sheet .125" Thick, 12" X 12"

Al Angle (Base Attachment)

Vendor - McMaster-Carr

Part No. - 88805K54

Cost - $14.87

Description - Alloy 6063 Aluminum 90 Degree Angle 1/8" Thick, 1" X 1/2" Legs, 8' Length

Fasteners

8-32 Flat Socket Cap Screws

Vendor - McMaster-Carr

Part No. - 92210A190

Cost - $11.58 (Pack of 100)

Description - 18-8 SS Flat Head Socket Cap Screw 8-32 Thread, 1/4" Length

M3 Screws (Drive Motor Mount)

Vendor - McMaster-Carr

Part No. - 92005A116

Cost - $2.16 (Pack of 100)

Description - Metric Pan Head Phillips Machine Screw Zinc-Plated Steel, M3 Size, 6mm Length, .5mm Pitch

8-32 Low Head Socket Cap Screw

Vendor - McMaster-Carr

Part No. - 92220A152

Cost - $11.60 (Pack of 100)

Description - Alloy Steel Low Head Socket Cap Screw 8-32 Thread, 3/8" Length

Other

1/2" Long Hex Stand Off

Vendor - McMaster-Carr

Part No. - 91780A195

Cost - $0.34 Each ($0.27 in bulk)

Description - Aluminum Female Threaded Hex Standoff 1/4" Hex, 1/2" Length, 8-32 Screw Size

5/16" Hex Broach

Vendor - McMaster-Carr

Part No. - 2875A17

Cost - $110.05

Description - Hexagon Broach 5/16" Hex, 7-3/4" Broach Length

1/4" E-Clips

Vendor - McMaster-Carr

Part No. - 97633A130

Cost - $6.54 (Pack of 100)

Description - Black-Phosphate Steel External Retaining Ring for 1/4" Shaft Diameter

Note - Inside of bearings

5/16" E-Clips

Vendor - McMaster-Carr

Part No. - 97633A150

Cost - $6.97 (Pack of 100)

Description - Black-Phosphate Steel External Retaining Ring for 5/16" Shaft Diameter

Note - Use behind omni due to hex size change.

Cost Estimate

1. Motors - $85.00
2. Fasteners - $0.90
3. Standoffs - $0.03 x 15 = $0.45
4. Output Shaft - $4.00
5. Output Gear - $24.00
6. Input Gear - $13.25
7. Plates -
8. Attachment -

Total - $128.60

Note - Shipping is included in per unit cost.

Action Log

1. 12/26/2007 - Inner and Outter Drive Module Plates completed.

   Note - Motor mount holes should be rotated a few (3-5 deg) for better motor cable fitting.

2. 01/27/2008 - Output shaft should be Steel 303, AL 2024, or AL 7075 (The AL is too weak to survive assembly)

   Note - The shafts we machined were out of spec and we should have paid to outsource them.

3. 02/24/2008 - All holes were move down 0.1in to allow for better ground clearance.

   Note - Hole needs to be made in bottom plate to allow for gear to poke threw will cover opening with tape to keep out carpet fibers.

4. 03/01/2008 - All gears will be stainless 303 and the output shaft will be a lower end steel.

   Note - This fixes shaft problems and some observed wear on the 2024 input gears.

5. 03/19/2008 - Switched to ABEC 3 bearings form grainger.

   Note - Reduces cost per bearing from $6.80 to $5.59.

6. 03/30/2008 - All holes moved down 0.1" and all standoffs repositioned.

   Note - Fixes low ground clearance concerns.

7. 04/06/2008 - Drive modules reshaped (for machining time) and finalized.