Mechanical Engineering Flashcards
What is a Mechanical function?
The role played by a specific part of a technical object, there a four basic mechanical functions: Link, Guiding, Lubrication, & Sealing.
What is Linking?
To join two parts together.
What is Guiding?
To guide another part in it’s motion.
What is Lubrication?
To limit friction between two parts.
What is Sealing?
To stop air and water from entering.
What is an example of a link?
- Glue
- Tape
- Screw
- Bolt
- Staples
What is an example of guiding?
- Rails
- Axle
What is an example of lubrication?
- Skis
- Snowboard
- Surfboard
- Oil
What is an example of sealing?
- O-rings
- Bottle cap
What are the three types of guiding? (Motion)
- Translational
- Rotational
- Helical
What is a Translational motion?
Motion in which all points of a moving body move uniformly in the same direction, side-to-side or up and down.
What is a Rotational motion?
Motion of an object around a circular path, in a fixed orbit.
What is a Helical motion?
Motion of an object in which goes side-to-side or up and down, while rotating around a circular path.
What is a Motion Transmission?
The mechanical function of relaying a motion from one part to another without altering the nature of the motion.
What is a Motion Transmission System?
A set of components that perform the function of a transmitting motion.
What is the Driver component?
The part that receives the force required to activate the system.
What is the Driven component?
The part that receives the motion and transfers it to another part.
What is the Intermediate component?
The part that is located in between the Driver & Driven components.
What are the types of Motion Transmission Systems? (5)
- Gear Trains
- Chain and sprocket systems
- Friction gear systems
- Belt and pulley systems
- Wheel and worm wheel systems
What is Gear Trains?
At least two gears that meet and mesh with each other, these gears transmit a rotational motion to each other. They always turn in opposite directions.
Are gear trains a reversible system?
Yes, the Driver and the Driven can swap places.
What is a Chain and sprocket system?
At least two gears that do not connect with each other and are connected by a chain. This systems transmits a rotational motion between two or more distant parts. These gears rotate in the same direction if they are inside the chain, and in the opposite direction if they are outside the chain.
Are Chain and sprocket systems reversible?
Yes.
What is a Friction gear system?
Similar to gear trains except that they don’t have teeth. Motion is transmitted by the friction between the gears, these gears move in opposite directions.
Are Friction gear systems reversible?
Yes, the Driver and Driven can swap places.
What are Belt and pulley systems?
Similar to chain and sprocket systems but have no teeth and are referred as pulleys. Connected by a belt, all pulleys inside the belt rotate in the same direction, where as all pulleys outside the belt rotate in opposite directions of the ones inside.
Are Belt and pulley systems reversible?
Yes.
What is a Wheel and worm wheel system?
Consists of a worm wheel whose rotational motion is transmitted to one or more wheels. Both parts rotate in the same direction.
Is a Wheel and worm wheel system reversible?
No, the driver component is always the worm wheel and the driven component is always the wheel.
What is a Motion Transformation system?
The function of relaying a motion from one part to another while altering the nature of the motion.
What are the four types of Motion Transformation system?
- Rack and pinion systems
- Screw-gear systems
- Cam and follower systems
- Slider-Crank mechanisms
What is a Rack and pinion system?
Contains a pinion (gear) and a rack (straight bar). This system changes a rotational motion of a pinion into a translational motion of the rack, or vice versa.
Is a Rack and pinion system reversible?
Yes.
What is a Screw-gear system?
Contains a screw and a nut. Transforms the rotational motion of a nut into the translational motion of a screw.
Is a Screw-gear system reversible?
No. The nut (rotates) is always the driver and the screw (translational) part is always the driven.
What is a Cam and follower system?
System which transforms the rotational motion of a cam into a translational motion of the follower.
Is a Cam and follower system reversible?
No. The cam is always the driver and the follower is always the driven.
What is a Slider-Crank system?
System which transforms the translational motion of the pistons into the rotational motion of the crank.
Is a Slider-crank system reversible?
Yes.
When is there a decrease in speed change in a Gear train & chain and sprocket systems?
There is a decrease in speed change when the driver gear has less teeth than the driven gear.
When is there a increase in speed change in a Gear train & chain and sprocket systems?
There is a increase in speed change when the driver gear has more teeth than the driven gear.
When is there no speed change in a a Gear train & chain and sprocket systems?
There is no speed change when the driver and driven gear have the same number of teeth.
When is there a decrease in speed change in a Friction gear & belt and pulley systems?
There is a decrease in speed change when the driver gear is smaller than the driven gear.
When is there an increase in speed change in a Friction gear & belt and pulley systems?
There is an increase in speed change when the driver gear is bigger than the driven gear.
When is there no speed change in a Friction gear & belt and pulley systems?
There is no speed change when the driver and driven gear have the same diameter.
