![Page 1: Gears and Cams Chapter 17. 2 Technical Drawing 13 th Edition Giesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart © 2009 Pearson Education, Upper](https://reader035.vdocuments.net/reader035/viewer/2022062321/56649ea75503460f94baa0d9/html5/thumbnails/1.jpg)
Gears and Cams
Chapter 17
![Page 2: Gears and Cams Chapter 17. 2 Technical Drawing 13 th Edition Giesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart © 2009 Pearson Education, Upper](https://reader035.vdocuments.net/reader035/viewer/2022062321/56649ea75503460f94baa0d9/html5/thumbnails/2.jpg)
2Technical Drawing 13th EditionGiesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart
© 2009 Pearson Education, Upper Saddle River, NJ 07458.
All Rights Reserved.
Objectives
• Define the characteristics of a spur gear, worm gear, and bevel gear
• Calculate the gear ratio and rpm of two mating gears, given the pitch diameters
• Define the principal spur gear terms• Draw a spur gear
![Page 3: Gears and Cams Chapter 17. 2 Technical Drawing 13 th Edition Giesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart © 2009 Pearson Education, Upper](https://reader035.vdocuments.net/reader035/viewer/2022062321/56649ea75503460f94baa0d9/html5/thumbnails/3.jpg)
3Technical Drawing 13th EditionGiesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart
© 2009 Pearson Education, Upper Saddle River, NJ 07458.
All Rights Reserved.
Objectives (cont.)
• Describe the relationship between a cam profile and a displacement diagram
• Draw a cam profile, given a displacement profile drawing
• List the types of cam followers
![Page 4: Gears and Cams Chapter 17. 2 Technical Drawing 13 th Edition Giesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart © 2009 Pearson Education, Upper](https://reader035.vdocuments.net/reader035/viewer/2022062321/56649ea75503460f94baa0d9/html5/thumbnails/4.jpg)
4Technical Drawing 13th EditionGiesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart
© 2009 Pearson Education, Upper Saddle River, NJ 07458.
All Rights Reserved.
Understanding Gears
• Gears are used to transmit power and rotating or reciprocating motion from one machine part to another
• ANSI/AGMA publishes detailed standards for gear design and drawings
![Page 5: Gears and Cams Chapter 17. 2 Technical Drawing 13 th Edition Giesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart © 2009 Pearson Education, Upper](https://reader035.vdocuments.net/reader035/viewer/2022062321/56649ea75503460f94baa0d9/html5/thumbnails/5.jpg)
5Technical Drawing 13th EditionGiesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart
© 2009 Pearson Education, Upper Saddle River, NJ 07458.
All Rights Reserved.
Spur Gears
• Proportions and shapes of gear teeth are well standardized
• The most common geometric form used in gears today is the involute profile• Involute means “rolled inward”
![Page 6: Gears and Cams Chapter 17. 2 Technical Drawing 13 th Edition Giesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart © 2009 Pearson Education, Upper](https://reader035.vdocuments.net/reader035/viewer/2022062321/56649ea75503460f94baa0d9/html5/thumbnails/6.jpg)
6Technical Drawing 13th EditionGiesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart
© 2009 Pearson Education, Upper Saddle River, NJ 07458.
All Rights Reserved.
![Page 7: Gears and Cams Chapter 17. 2 Technical Drawing 13 th Edition Giesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart © 2009 Pearson Education, Upper](https://reader035.vdocuments.net/reader035/viewer/2022062321/56649ea75503460f94baa0d9/html5/thumbnails/7.jpg)
7Technical Drawing 13th EditionGiesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart
© 2009 Pearson Education, Upper Saddle River, NJ 07458.
All Rights Reserved.
Constructing a Base Circle
![Page 8: Gears and Cams Chapter 17. 2 Technical Drawing 13 th Edition Giesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart © 2009 Pearson Education, Upper](https://reader035.vdocuments.net/reader035/viewer/2022062321/56649ea75503460f94baa0d9/html5/thumbnails/8.jpg)
8Technical Drawing 13th EditionGiesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart
© 2009 Pearson Education, Upper Saddle River, NJ 07458.
All Rights Reserved.
The Involute Tooth Shape
![Page 9: Gears and Cams Chapter 17. 2 Technical Drawing 13 th Edition Giesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart © 2009 Pearson Education, Upper](https://reader035.vdocuments.net/reader035/viewer/2022062321/56649ea75503460f94baa0d9/html5/thumbnails/9.jpg)
9Technical Drawing 13th EditionGiesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart
© 2009 Pearson Education, Upper Saddle River, NJ 07458.
All Rights Reserved.
Spacing Gear Teeth
• Teeth are spaced around the periphery by laying out equal angles
• The number of spaces should be twice the number of teeth, equal to the tooth thickness at the pitch circle
![Page 10: Gears and Cams Chapter 17. 2 Technical Drawing 13 th Edition Giesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart © 2009 Pearson Education, Upper](https://reader035.vdocuments.net/reader035/viewer/2022062321/56649ea75503460f94baa0d9/html5/thumbnails/10.jpg)
10Technical Drawing 13th EditionGiesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart
© 2009 Pearson Education, Upper Saddle River, NJ 07458.
All Rights Reserved.
Spacing Gear Teeth
![Page 11: Gears and Cams Chapter 17. 2 Technical Drawing 13 th Edition Giesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart © 2009 Pearson Education, Upper](https://reader035.vdocuments.net/reader035/viewer/2022062321/56649ea75503460f94baa0d9/html5/thumbnails/11.jpg)
11Technical Drawing 13th EditionGiesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart
© 2009 Pearson Education, Upper Saddle River, NJ 07458.
All Rights Reserved.
Rack Teeth
• Gear teeth formed on a flat surface are called a rack
![Page 12: Gears and Cams Chapter 17. 2 Technical Drawing 13 th Edition Giesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart © 2009 Pearson Education, Upper](https://reader035.vdocuments.net/reader035/viewer/2022062321/56649ea75503460f94baa0d9/html5/thumbnails/12.jpg)
12Technical Drawing 13th EditionGiesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart
© 2009 Pearson Education, Upper Saddle River, NJ 07458.
All Rights Reserved.
Working Drawings of Spur Gears• Since teeth are cut to a standard
shape, individual teeth are not typically shown
![Page 13: Gears and Cams Chapter 17. 2 Technical Drawing 13 th Edition Giesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart © 2009 Pearson Education, Upper](https://reader035.vdocuments.net/reader035/viewer/2022062321/56649ea75503460f94baa0d9/html5/thumbnails/13.jpg)
13Technical Drawing 13th EditionGiesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart
© 2009 Pearson Education, Upper Saddle River, NJ 07458.
All Rights Reserved.
Spur Gear Design
• Spur gear design normally begins with selecting pitch diameter
• The size of the teeth (diametral pitch) depends on:• Gear speeds• Gear materials• Horsepower to be transmitted• Tooth form
![Page 14: Gears and Cams Chapter 17. 2 Technical Drawing 13 th Edition Giesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart © 2009 Pearson Education, Upper](https://reader035.vdocuments.net/reader035/viewer/2022062321/56649ea75503460f94baa0d9/html5/thumbnails/14.jpg)
14Technical Drawing 13th EditionGiesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart
© 2009 Pearson Education, Upper Saddle River, NJ 07458.
All Rights Reserved.
Worm Gears
• Worm gears are used to transmit power between nonintersecting shafts that are at right angles to each other
• A worm is a screw with a thread shaped like a rack tooth
• Worm wheels are similar to helical gears cut to conform to the shape of the worm
![Page 15: Gears and Cams Chapter 17. 2 Technical Drawing 13 th Edition Giesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart © 2009 Pearson Education, Upper](https://reader035.vdocuments.net/reader035/viewer/2022062321/56649ea75503460f94baa0d9/html5/thumbnails/15.jpg)
15Technical Drawing 13th EditionGiesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart
© 2009 Pearson Education, Upper Saddle River, NJ 07458.
All Rights Reserved.
Worm Gears
![Page 16: Gears and Cams Chapter 17. 2 Technical Drawing 13 th Edition Giesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart © 2009 Pearson Education, Upper](https://reader035.vdocuments.net/reader035/viewer/2022062321/56649ea75503460f94baa0d9/html5/thumbnails/16.jpg)
16Technical Drawing 13th EditionGiesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart
© 2009 Pearson Education, Upper Saddle River, NJ 07458.
All Rights Reserved.
Working Drawings of Worm Gears• In assembly drawings, gear teeth
are omitted and the gear blank represented conventionally
• On detail drawings, the worm and gear are usually drawn separately
![Page 17: Gears and Cams Chapter 17. 2 Technical Drawing 13 th Edition Giesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart © 2009 Pearson Education, Upper](https://reader035.vdocuments.net/reader035/viewer/2022062321/56649ea75503460f94baa0d9/html5/thumbnails/17.jpg)
17Technical Drawing 13th EditionGiesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart
© 2009 Pearson Education, Upper Saddle River, NJ 07458.
All Rights Reserved.
Bevel Gears
• Bevel gears transmit power between shafts whose axes intersect at any angle
• Bevel gear teeth have the same involute shape as teeth on spur gears but are tapered toward the cone apex
![Page 18: Gears and Cams Chapter 17. 2 Technical Drawing 13 th Edition Giesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart © 2009 Pearson Education, Upper](https://reader035.vdocuments.net/reader035/viewer/2022062321/56649ea75503460f94baa0d9/html5/thumbnails/18.jpg)
18Technical Drawing 13th EditionGiesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart
© 2009 Pearson Education, Upper Saddle River, NJ 07458.
All Rights Reserved.
Bevel Gears
![Page 19: Gears and Cams Chapter 17. 2 Technical Drawing 13 th Edition Giesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart © 2009 Pearson Education, Upper](https://reader035.vdocuments.net/reader035/viewer/2022062321/56649ea75503460f94baa0d9/html5/thumbnails/19.jpg)
19Technical Drawing 13th EditionGiesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart
© 2009 Pearson Education, Upper Saddle River, NJ 07458.
All Rights Reserved.
Bevel Gear Terminology
![Page 20: Gears and Cams Chapter 17. 2 Technical Drawing 13 th Edition Giesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart © 2009 Pearson Education, Upper](https://reader035.vdocuments.net/reader035/viewer/2022062321/56649ea75503460f94baa0d9/html5/thumbnails/20.jpg)
20Technical Drawing 13th EditionGiesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart
© 2009 Pearson Education, Upper Saddle River, NJ 07458.
All Rights Reserved.
Working Drawings of Bevel Gears• Working drawings for bevel gears
give only the dimensions of the gear blank
• Data necessary for cutting teeth are given in a note or table
![Page 21: Gears and Cams Chapter 17. 2 Technical Drawing 13 th Edition Giesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart © 2009 Pearson Education, Upper](https://reader035.vdocuments.net/reader035/viewer/2022062321/56649ea75503460f94baa0d9/html5/thumbnails/21.jpg)
21Technical Drawing 13th EditionGiesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart
© 2009 Pearson Education, Upper Saddle River, NJ 07458.
All Rights Reserved.
Cams
• Cams can be used to produce irregular motions• A shaft rotating at uniform speed
carries the cam• A reciprocating member, called the
follower, presses a roller against the curved surface of the cam
• Rotating the cam causes the follower to reciprocate a cyclic motion according to the cam profile
![Page 22: Gears and Cams Chapter 17. 2 Technical Drawing 13 th Edition Giesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart © 2009 Pearson Education, Upper](https://reader035.vdocuments.net/reader035/viewer/2022062321/56649ea75503460f94baa0d9/html5/thumbnails/22.jpg)
22Technical Drawing 13th EditionGiesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart
© 2009 Pearson Education, Upper Saddle River, NJ 07458.
All Rights Reserved.
Cams
![Page 23: Gears and Cams Chapter 17. 2 Technical Drawing 13 th Edition Giesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart © 2009 Pearson Education, Upper](https://reader035.vdocuments.net/reader035/viewer/2022062321/56649ea75503460f94baa0d9/html5/thumbnails/23.jpg)
23Technical Drawing 13th EditionGiesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart
© 2009 Pearson Education, Upper Saddle River, NJ 07458.
All Rights Reserved.
Displacement Diagrams
• A displacement diagram is a curve showing the displacement of the follower as ordinates on a base line that represents one revolution of the cam
• The motion of the follower as it rises or falls depends on the shape of the curves in the displacement diagram
![Page 24: Gears and Cams Chapter 17. 2 Technical Drawing 13 th Edition Giesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart © 2009 Pearson Education, Upper](https://reader035.vdocuments.net/reader035/viewer/2022062321/56649ea75503460f94baa0d9/html5/thumbnails/24.jpg)
24Technical Drawing 13th EditionGiesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart
© 2009 Pearson Education, Upper Saddle River, NJ 07458.
All Rights Reserved.
Displacement Diagrams
![Page 25: Gears and Cams Chapter 17. 2 Technical Drawing 13 th Edition Giesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart © 2009 Pearson Education, Upper](https://reader035.vdocuments.net/reader035/viewer/2022062321/56649ea75503460f94baa0d9/html5/thumbnails/25.jpg)
25Technical Drawing 13th EditionGiesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart
© 2009 Pearson Education, Upper Saddle River, NJ 07458.
All Rights Reserved.
Cam Profiles
![Page 26: Gears and Cams Chapter 17. 2 Technical Drawing 13 th Edition Giesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart © 2009 Pearson Education, Upper](https://reader035.vdocuments.net/reader035/viewer/2022062321/56649ea75503460f94baa0d9/html5/thumbnails/26.jpg)
26Technical Drawing 13th EditionGiesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart
© 2009 Pearson Education, Upper Saddle River, NJ 07458.
All Rights Reserved.
Cylindrical Cams
• When the follower movement is in a plane parallel to the cam shaft, a cylindrical cam must be employed
![Page 27: Gears and Cams Chapter 17. 2 Technical Drawing 13 th Edition Giesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart © 2009 Pearson Education, Upper](https://reader035.vdocuments.net/reader035/viewer/2022062321/56649ea75503460f94baa0d9/html5/thumbnails/27.jpg)
27Technical Drawing 13th EditionGiesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart
© 2009 Pearson Education, Upper Saddle River, NJ 07458.
All Rights Reserved.
Cylindrical Cams