Rotary motion gears

Gears are used almost entirely in rotary motion applications, and as such it is easier to discuss the mechanical advantage as a multiplication of torque rather than as a multiplication of force. The work involved in rotary motion is torque times angle whereas for the linear motion discussed above, it is force times distance. 

A mixture of air and a fine spray of gasoline at ambient (outside air) temperature is fed to a set of piston-fitted cylinders in an automobile engine. Sparks ignite the combustible mixtures in one cylinder after another, and the consequent rapid increase in temperature in the cylinders causes the combustion products to expand and drive the pistons. The back-and-forth motion of the pistons is converted to rotary motion of a crank shaft, motion that in turn is transmitted through a system of shafts and gears to propel the car. 

A metering pump consists of drive with gear reducer and a pumphead, where the gear reduces the rotary motion of the drive motor and coverts it into a reciprocating... 

Molecular systems that exhibit controlled or coordinated rotary motion are discussed in this chapter. These systems represent a reproduction of a variety of macroscopic mechanical devices on the molecular scale. From gears to a motor, passing through a turnstile, a brake and a ratchet, we describe their design, synthesis and dynamic behavior. The importance of molecular motors in the biological realm and possible applications in nanotechnology are also discussed. 

Rack and Pinion A mechanism that converts rotary motion to linear motion is the rack-and-pinion gear (Figure 10-12). If you look at the mechanism that opens the CD drive on your computer, you would find a... 

FIGURE 10-14 The gear train is used to transfer rotary motion. It can change the speed or torciue of the motion. Each gear turns in the opposite direction of its drive gear. You can see gear trains at work on bicycles. 

FIGURE 10-15 evel gears are used to change the direction of rotary motion in roboticarms. 

Your engineering team needs to design a set of gears or a gear train to transfer rotary motion. The input speed from a motor is 1,560 rpm. 

FIGURE 10-16 Thecrown-and-pinion gear changes the direction of the rotary motion and typically increases its torciue. Fishing reels use crown-and-pinion gears. 

FIGURE 10-17 The worm gear transfers rotary motion while changing direction and increasing torciue. 

The major uses of gears and gear drives are to transmit power, with reduction or increase of speed and multiplication of torque. In addition, gears are used to transmit rotary motion from one shaft to another in a uniform manner, and for positioning. Gear drives are usually classified as reducers, increasers, high-speed drives, or drives for the accurate positioning of loads. 

Used intelligently, flexible shafts are the product designer s allies. They are more flexible than universal joints they are more versatile than gear systems because they are totally unaffected by the exact angle or offset necessary finally, flexible shafts offer an inherent shock-absorption capability, ease of installation, and maintenance unmatched by other forms of rotary-motion transmission. 

The helical-lobe compressor is further divided into a dry and a flooded form. The dry fonn uses timing gears to hold a prescribed timing to tlie relative motion of the rotors the flooded form uses a liquid media to keep the rotors from touching. The helical-lobe compressor is the most sophisticated and versatile of the rotary compressor group and operates at the highest rotor tip Mach number of any of the compressors in the rotary family. This compressor is usually referred to as the screw compressor or the SRM compressor. ... 

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