Queensland University: EGH420 Gearbox Power System Design Report

This report details the design of a gearbox power system, focusing on the development of a test machine capable of accommodating interchangeable gearboxes. The project includes an executive summary, background information, and a detailed literature review of existing gearbox testing methods, categorizing designs into Back to Back Open Circuit and Back to Back Closed Circuit systems. The report also analyzes various load cases and motor specifications, presenting a design matrix to evaluate different conceptual designs based on criteria such as speed, load, noise, and material performance. It highlights the functional and non-functional requirements of the system, including use cases for load, testing, and maintenance. The design incorporates both parallel and cross-axis gearboxes, and concludes with a Gantt chart outlining the project's requirements. This work was completed as part of the EGH420 course at Queensland University of Technology.

Running head: DESIGNING OF A GEARBOX POWER
Designing of a gearbox power
Name of the student:
Name of the university:
Author note:

1DESIGNING OF A GEARBOX POWER
Executive Summary
The following report is prepared so as to outline the importance of the working of the proposed
system design of gearbox power systems that helps in testing the efficiency of the apparatus
while accommodating interchangeable gearboxes. The research includes detailed analysis of the
system design while enabling the evaluation of its efficiency and effectiveness of its overall
performances. As a part of the report, a detailed literature review is done based on the testing of
the designed machine which is broken up into two different categories such as the Back to Back
Open Circuit and the other as the Back to Back Close Circuit. In the next part of the review, the
detailed categories of the gearbox system re described with their supporting diagrams.
Depending on the category of the design, the load cases of the gear box test machine has been
evaluated. After conducting relevant research on the specification of the motor, a summary chart
has been produced where it is seen that the power ratings ranges from 0.55 kw giving a safety
factor of 1.1 that benefits the range of common efficiency of the motors to about 50% to 100%.
The report also consists of detail analysis of the proposed designing of the system based on
certain prioritized criteria such as speed, load, noise, performance of the lubrication, power loss,
Stress, Strain and the performance of the material. In order to proceed with the designed system,
a decision matrix is hence designed consisting of several metrics and their specified or calculated
weightage based on the three types of conceptual design that has been proposed in the entire
design. In order to design the proposed gearbox system, the desired functional requirements
needed for each of the components like driving motor, shafts, couplings, reducer gearbox. Load
motor and test bench has been highlighted. The entire report also consisted of the analysis of the
load cases for each of the components of the gears system considering their time and history as
displayed with tables. A detailed analysis of the work flow of the gearbox system has been

2DESIGNING OF A GEARBOX POWER
discussed while justifying the suitability of its proposed design and analyzing the errors that has
been discovered within the analysis process. Finally, the report concludes with a detailed
presentation of a Gantt Chart analyzing all the requirements of the Gearbox system design.

3DESIGNING OF A GEARBOX POWER
Background of the project:
1. Purpose of the design:
The designing of the gearbox power is conducted so as to accommodate the
interchangeable gearboxes that drives up to 0.5 kw and has a dynamometer at the output
so as to load the system and evaluates its efficiency. The designed gearbox aims at
transmitting power in between the rotating shafts.
2. System description:
For mechanical industry it is very much critical to test the effectiveness as well as
the efficiency of the gearboxes while developing important components for the industry.
The designing of gearbox that has been conducted in this project includes the objective s
as to develop testing apparatus allowing individuals to test the developed gearboxes while
helping to evaluate the efficiency, overall performance and torque of the gearbox design
[1]. Different types of designs have been developed so as to determine the efficiency and
power of a gearbox. Based on that, the designing of the gear box has been split into two
different categories consisting of one Back to Back Open Circuit and the other as the
Back to Back Closed Circuit [3]. The designing of the system is then further improved by
introducing a reducer gearbox that helps in reducing the speed and enlarging the torque of
the system. Besides that, several other iteration has also been designed so as to test the
power and efficiency of the gearbox system.
3. Working of the system:
The designing of the gearbox utilizes the high speed driving motor in order to
control the loading of the gearbox. From this the efficiency of the gearbox can be
calculated based on the input and output of the sensory data. The designing of the reducer

4DESIGNING OF A GEARBOX POWER
test machine allows system to be more cost effective while driving the motor. The
conceptual design of the modular test machine works on the modular bench system while
allowing the testing of gearbox for both parallel and cross axis gearboxes [4]. This test
machine reduces the incorporation of the gearbox while minimizing the torque to the load
motor. This working of the system increases the complexity while increasing the
functional ability to test both the parallel and cross axis gearboxes.
4. Use of the design:
The gearbox is designed so as to transmit power in between rotating shafts. This
design is most commonly used in motor vehicle industry where the transmission power of
the gearbox needs to adapt output of the internal combustion engine of the driving wheels
[2]. The design can also be utilized in wind turbine that converts the high torque rotation
of the turbine into a faster version so as to generate electricity.
5. Importance of the design:
The importance of a gearbox test apparatus helps in transmission of power while
providing the reduction in speed and helping in to multiply the torque that is received
from the engine. The importance of the design mainly lies with its application in the
automobile industry. Implementing a gear box transmission system helps in controlling
the power applications while allowing the gear trains to provide the conversion of speed
and torque from the rotating power of one source to the other.
Scope:
Areas that need to be designed:
The areas that need to designed within the proposed design of the gear box system
includes the designing of the test machines including the open circuit as well as the components

5DESIGNING OF A GEARBOX POWER
of closed circuit. The startup torques also requires designing so as to accelerate the system and to
overcome the loss in friction while in use. Besides all these designing needs, two types of
gearboxes also need to be incorporated that is the parallel axis and the other is the cross axis.
Within the Simple Parallel Test Machine, a reducer needs to be introduced.
Areas that will benefit from the existing components:
Implementing the close loop test machine will bring in several benefits as compared to
the open loop test machines. The design will recirculate the generated energy from the power
source with the help of feedback devices while decreasing the energy that will be required to
load the gear box. Another benefit that is incurred from the existing components of a close
looped machine is that it helps in locking up of the torque in the system without the need of any
secondary motor. The designing of the gear box will benefit in reducing the transmitted torque
while enabling the dynamometer to stay within the same size and input. The application of top
shaft at the closed loop machine will act as the torque arm that helps in supplying the resistance
to the circuit using the clutch and the load arm.
Uniqueness of the proposed design: The proposed design of the modular test machine has high
functionality and provides the ability to test all types of gear boxes.
Indicators:

6DESIGNING OF A GEARBOX POWER
Design matrix:
Design 1 Design 2 Design 3
Metrics Weight Score Weighte
d
Score
Score Weighte
d
Score
Score Weighte
d
Score
Simplicity 5 10 5 8 4 1 0.5
Cost 20 10 20 6 12 1 2
Reliability 30 5 15 8 24 8 24
Safety 25 3 7.5 7 17.5 6 15
Functionality 10 6 6 6 6 10 10
Maintainability 8 8 6.4 5 4 5 4
Ergonomics 2 6 1.2 6 1.2 5 1
Weighted Total 100 61.1 68.7 56.5
Importance of indicators in the design matrix:
The indicators within the design matrix helps in evaluating the decision matrix while
helping in analyzing the reliability, safety, and costs that are related to the success of the
designed system.
Client requirements:
 Functional requirements: The functional requirements of the system include-
1. Measuring of the input and the out including the speed, loads, power, torques and its
efficiency
2. Applying the variable load to the gear box
3. Applying bearings that helps in reducing the friction and motion
4. Implementing easy interchangeable gearboxes
5. Implementing motors to produce the power inputs

7DESIGNING OF A GEARBOX POWER
6. Adaptable gearboxes
 Non-functional requirements:
The non-functional requirements of the system include-
1. Ergonomics
2. Safety
3. Weight
4. Budget
5. Manufacturability
6. Scalability
7. Performance
8. Physical attribute
Use cases:
The various use cases that are included within the system design of the gear box includes-
1. Load
2. Testing the gearboxes
3. Maintaining the repaired and replacing parts
4. General maintenance and inspection

8DESIGNING OF A GEARBOX POWER
References:
[1] J. S. Nam, Y. J. Park, S. J. Jo, H. S. Kim, and S. B. Shim, ‘Development of a gearbox test rig
with non-torque loading capacity’, J. Mech. Sci. Technol., vol. 30, no. 4, pp. 1713– 1722, Apr.
2016.
[2] A. Lomate, S. S. Mohite, and R. M. Shinde, ‘Design and Development of Torque Testing Rig
for a Gearbox’, 2010.
[3] M. A. Sargeant, S. J. Drew, and B. J. Stone, ‘Coupled Torsional and Transverse Vibration of
a Back-to-Back Gearbox Rig’, Proc. Inst. Mech. Eng. Part K J. Multi-Body Dyn., vol. 219, no. 3,
pp. 259–273, Sep. 2005.
[4] B. A. Leishman, S. J. Drew, and B. J. Stone, ‘Torsional vibration of a back-to-back gearbox
rig Part 1: Frequency domain modal analysis’, Proc. Inst. Mech. Eng. Part K J. Multi-Body Dyn.,
vol. 214, no. 3, pp. 143–162, Sep. 2000.