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Engineering Design
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CLO 2 : DESIGN THE SIMPLE ENGINEERING COMPONENT USING MATHEMATICAL ANALYSIS METHOD ACCORDING TO SAFE LOAD LIMITATION.
CLO3 : RELATE THE BASIC CONCEPT AND PRINCIPLE TO SOLVE THE PROBLEMS IN OF ENGINEERING DESIGN.
PLO4 : CRITICAL THINKING AND PROBLEM SOLVING SKILLS
Spur gears are by far the most common type of gear and with the exceptions of the "cog" the type of gear that has been around the
longest. Spur gears have teeth that run perpendicular to the face of the gear.
Spur gear setakat ini jenis yang paling biasa digunakan dan jenis gear yang telah wujud yang paling lama. Spur gear mempunyai gigi yang berjalan berserenjang dengan muka gear.
Helical gears are very similar to spur gears except the teeth are not perpendicular to the face. The teeth are at an
angle to the face giving helical gears more tooth contact in the same area.
Gear heliks adalah serupa dengan spur gear kecuali gigi tidak berserenjang dengan muka. Gigi pada sudut muka memberi gear heliks gigi hubungan yang lebih di kawasan yang sama.
Helical gears can also be used on non-parallel shafts to transmit motion.
Gear heliks juga boleh digunakan pada aci tidak selari untuk menghantar gerakan
Helical gears tend to run quieter and smoother than spur gears due to the increased number of teeth in constant
contact at any one period of time.Gear heliks cenderung untuk berjalan lebih senyap dan lancar daripada gear taji disebabkan oleh
peningkatan bilangan gigi dalam hubungan yang berterusan di mana-mana satu tempoh masa
Herringbone gears resemble two helical gears that have been placed side by side.
They are often referred to as "double helicals".
Gear tulang hering menyerupai dua gear heliks yang telah diletakkan sebelah menyebelah. Mereka sering dirujuk sebagai "helicals double“
One benefit of herringbone gears is that it helps to avoid issues related to side thrust
created with the use of helical gears.Salah satu manfaat gear tulang hering adalah bahawa ia membantu untuk mengelak isu-isu yang
berkaitan dengan tujahan sisi yang dicipta dalam penggunaan gear heliks.
Bevel gears are used mostly in situations that require power to be transmitted at right
angles (or applications that are not parallel). Bevel gears can have different angles of application but tend to be 90°.
Gear serong kebanyakannya digunakan dalam situasi yang memerlukan kuasa yang akan dihantar pada sudut tepat (atau aplikasi yang tidak selari). Gear serong boleh mempunyai sudut yang
berbeza permohonan tetapi cenderung untuk menjadi 90 °.
Worm gears are used to transmit power at 90° and where high reductions are required. The worm resembles a thread that rides in
concaved or helical teeth.Gear cacing digunakan untuk menghantar kuasa pada 90 ° dan di mana pengurangan tinggi
diperlukan. Cacing mirip benang yang baris dalam gigi concaved atau heliks.
Internal gears typically resemble inverted spur gears but are occasionally cut as
helical gears.Gear Dalaman biasanya menyerupai gear taji terbalik tetapi kadang-kadang dipotong sebagai gear
heliks.
A rack is basically a straight gear used to transmit power and motion in a linear
movement.Rak adalah asasnya gear lurus yang digunakan untuk menghantar kuasa dan gerakan dalam gerakan
linear.
Face gears transmit power at (usually) right angles in a circular motion. Face gears are not very common in industrial application.
Gear Wajah menghantar kuasa pada (biasanya) sudut kanan dalam gerakan membulat. Gear Wajah tidak begitu biasa dalam aplikasi perindustrian.
Differential Gears
The gear ratio of a gear train is the ratio of the angular velocity of the input gear to the angular velocity of the output gear, also
known as the speed ratio of the gear train.The gear ratio can be calculated directly from the number of teeth of the various gears that engage to form the gear train. The torque ratio of the gear
train.Nisbah gear pada gear train adalah nisbah halaju sudut gear input ke halaju sudut gear output, juga
dikenali sebagai nisbah kelajuan gear train tersebut. Nisbah gear boleh dikira secara langsung dari bilangan gigi gear pelbagai yang terlibat untuk membentuk gear train.
The input or drive gear in a gear train is generally connected to a power source, such as a motor or engine. The drive gear engages the remaining gears in the gear train, and transmits power to the
output or driven gear.Input atau gear pemacu di gear train secara amnya disambungkan ke sumber kuasa, seperti motor
atau enjin. Gear pemacu melibatkan lebihan gear dalam gear train, dan menghantar kuasa ke keluaran atau gear yang dipacu.
Simple gear train with two gears
The simplest gear train is a pair of meshing gears in which the input gear drives the output gear. Gear teeth are designed so the pitch circles of the two gears roll on
each other without slipping. The velocities v of the points of contact of the two pitch circles are the same, therefore
where input gear GA has radius rA and angular velocity , and meshes with output gear GB of radius rB and angular velocity .
The number of teeth on a gear is proportional to the radius of its pitch circle, this means that the ratio of the radii equals the ratio
of the number of teeth, that is
where NA is the number of teeth on the input gear and NB is the number of teeth on the output gear.
This shows that a simple gear train with two gears has the gear ratio R given by
This equation shows that if the number of teeth on the output gear GB is larger than the number of teeth on the input gear GA, then the input gear GA must rotate faster than the output gear GB.
Simple gear train with an idlerIf a simple gear train has three gears, so that the input gear GA meshes with an intermediate gear GI which in turn meshes with the output gear GB, then the pitch circle of the intermediate gear
rolls without slipping on both the pitch circles of the input and output gears. This yields the two relations
The speed ratio of this gear train is obtained by multiplying these two equations to obtain
The teeth of a gear are distributed on the circumference of the pitch circle so that the thickness of each tooth t and the space between
two teeth are the same. The pitch p of a gear, which is the distance between the equivalent points on two teeth, is equal to
twice the thickness of a tooth,
The pitch of a gear GA can be computed from the number of teeth NA and the radius rA of its pitch circle
In order to mesh smoothly two gears GA and GB must have the same sized teeth and therefore they must have the same pitch p, which
means
This equation shows that the ratio of the circumference, the diameters and the radii of two meshing gears is equal to the ratio of
their number of teeth,
The speed ratio of two gears rolling without slipping on their pitch circles is given by,
Therefore,
In other words, the gear ratio, or speed ratio, is inversely proportional to ratio of the radii of the pitch circles and the number of teeth of
the two gears.
A gear train can be analyzed using the principle of virtual work to show that its torque ratio, which is the ratio of its output torque to
its input torque, is equal to the gear ratio, or speed ratio, of the gear train.This means that the input torque TA applied to the input
gear GA and the output torque TB" on the output gear GB are related by the ratio
where R is the gear ratio of the gear train.The torque ratio of a gear train is also known as its mechanical
advantage, thus
Two involute gears, the left driving the right: Blue arrows show the contact forces between them. The force line (or Line of Action) runs along a tangent common to both base circles. (In this situation, there is no force, and no contact needed, along the opposite common tangent not shown.)
The involutes here are traced out in converse fashion: points (of contact) move along the stationary force-vector "string" as if it was being unwound from the left rotating
base circle, and wound onto the right rotating base circle.
Dua gear, kiri memandu anak panah kanan: Garisan Biru menunjukkan daya sentuhan antara mereka. Barisan daya (atau Garis Tindakan) beroperasi di sepanjang tangen biasa untuk kedua-dua bulatan
asas. (Dalam keadaan ini, tiada daya dan sentuhan tidak diperlukan, bersama-sama tangen sepunya bertentangan tidak ditunjukkan.) The involutes di sini dikesan dalam keadaan sebaliknya: titik (daripada sentuhan) bergerak di sepanjang daya vektor pegun "rentetan" sebagai jika ia tidak
berlilit dari kiri bulatan asas berputar, dan digulung ke kanan bulatan asas berputar.
