See Chapter 15 of the text. You will design the main components of a single-reduction spur gear-type

speed reducer, similar to the one in Section 15-5. Submit your project as a Formal Report.

Speed Reducer Specifications

Pinion and gear must transmit 25 HP.

Pinion speed is 2000 RPM and gear speed is 500 RPM. The gear ratio is 4:1.

Design Requirements

• Design a pinion and gear to transmit 25 HP with a pinion speed of 2000 RPM and a gear speed of

500 RPM. The gear ratio is 4:1. Design for strength and pitting resistance to achieve

approximately 20,000 hours of life with a reliability of at least 99.9%

Design two shafts, one for the pinion and one for the gear. Provide positive axial location for

the gears on the shaft. The input shaft must be designed to extend beyond the housing to

enable the motor shaft to be coupled to it. The output shaft must accommodate a coupling that

mates with the drive shaft of the saw. Use a design reliability of 99.9%

• Specify four commercially available rolling contact bearings, two for each shaft. The L₁0 design

life should be 20,000 hours.

Project Deliverables

Introduction - In one well-written paragraph, summarize the function of this single-reduction

spur gear-type speed reducer, inspired by Section 15-5 in the text.

For the pinion and gear, provide the following data in one table. Use proper units.

o Diametral Pitch

o Number of teeth on pinion

Number of teeth on gear

Diameter of pinion [in]

00/nO

Diameter of pinion [in]

Diameter of gear [in]

Center distance [in]

O

O

Face width [in]

o Tangential force [lbf]

o Required bending stress number for pinion [psi]

o Required contact stress number for pinion [psi]

o Material of construction

o Drawings of pinion and gear are not required

For the shafts, provide the following data and figures:

o

Input shaft: geometry, loads, shearing force, bending moment, and torque diagrams in

one figure. (See Figure 15-4 in the text.)

o Output shaft: geometry, loads, shearing force, bending moment, and torque diagrams in

one figure. (See Figure 15-4 in the text.)

o

In one data table, specify the following for both the input shaft and the output shaft:

• Support reactions - bearing forces [lbf]

• Maximum bending moment [lbf-in]

.

Maximum torque [lbf-in]

Material of construction

• Design factor

Minimum allowable shaft diameters [in]/no Provide an engineering drawing of the input shaft. See Figure 15-6 and 15-7 in the text.

You do not have to include keyway detail, since key design is not part of this project.

For the bearings, provide the following in one data table:

o

Input shaft: design life [rev]

o

Input shaft: required basic dynamic load rating [lbf]

o

Input shaft: specified bearings

o Output shaft: design life [rev]

o Output shaft: required basic dynamic load rating [lbf]

o Output shaft: specified bearings

Summary-In one well-written paragraph per subject, summarize the work done to specify the

pinion-gear system, complete the initial design of the input and output shafts, and specify the

rolling contact bearings. Answer the following questions as well:

o

Why is it so important to apply the proper safety/design factor in the design stage, and

how does this affect society?

o

If you were an engineer working for a company and you noticed a co-worker made a

mistake on a drawing that could impact the safety of the design, what would you do?

Appendix - Include the following:

o A screenshot of every completed spreadsheet used in this project. Label each

screenshot so as to describe the purpose of the calculations.

o

An example of every calculation performed by hand on this project. Label each

calculation to describe its purpose. Neat, handwritten work is acceptable here. Proper

display of units is required.