Spur Gear Advantages Disadvantages Efficient andeasy to assemble Straight teeth that are easy to align Minimal power lost due to slippage Loud at high speeds Must be used in parallel Not as strong as other gears The advantages of using spur gears in your application may be obvious.
E Type: Keyless spur gear has a similar shape to the A type gear but has a bushing fastened to the outside of the gear. G Type: Keyless spur gear is similar to our B Type gear, but has a bushing attached to the outside of the gear. Bevel Bevel gears are used for intersecting shafts and have a changeable operating angle due to their shape.
Straight Type: Similar to spur gears and prone to suffering from backlash and excessive noise. Spiral Type: Similar to helical gears due to their similar tooth orientations, quieter than the spiral but prone to tooth slippage. Share this Story. About Carlicia Layosa. She holds a bachelor's degree in Mechanical Engineering and a master's degree in Energy Engineering from the University of Illinois at Chicago.
Featured Articles. Now that you have more background information Load More Related Articles. Mechanical Design. Bearing Lubrication This post is a continuation of the Koyo Bearings series, you can find the original post on their website Consumer Packaging Industry Insights. Now more than ever, consumer products ranging from toothpaste to potato chips and cleaning wipes to nail polish can be delivered Industry Insights Medical.
Spectroscopy to Clinical Chemistry Analyzers The medical industry is experiencing massive growth, especially in the Lab Automation space. The need for Bearing Preload and Rigidity This post is a continuation of the Koyo Bearings series, you can find the original post on October 5, September 21, In all corners of the world, healthcare has been one of the most important industries of the last year and a September 14, Load More By Carlicia Layosa.
July 27, April 27, January 13, Featured Articles Mechanical Design. February 11, The teeth on a screw gear are in the form of a helix. They form a point of contact between two gears and hence are not very suitable for high load and high-speed applications. They also have low efficiency compared to other helical gears. A unique trait of screw gears is that they use the same hand pair when engaging. Motion is transmitted as the same hand pairs slide against each other. Lubrication of screw gears is therefore a necessity.
There are no limitations on the combination of the number of teeth. The types of gear we call bevel are cone-shaped, placing the teeth on the conical surface. The cone top is lopped off.
The two mating gears are generally placed on perpendicular intersecting shaft axes. One of the most common uses for bevel gears is for changing the power transmission axis.
While doing so, RPM and torque may be changed as necessary by varying the gear size. There is also the option to increase or decrease the angle between the shafts. The two shafts need not be exactly perpendicular. Due to the design of bevel gear, when two mating teeth come in contact, the contact takes place all at once instead of gradually. Thus, a similar problem of high stress as in the case of spur gears occurs.
This high impact mating produces more noise and causes excessive stress on the gear tooth. The high stress ultimately affects the durability and service life of the bevel gear. It also affects the sort of applications they are used for. Despite these limitations, they find use in many different industries. Some of the equipment that uses bevel gears are automobiles, pumps, machine tools milling and turning , food packaging equipment, fluid control valves, and gardening equipment.
They are also the easiest to manufacture and hence, are quite affordable and available in a variety of sizes. Spiral bevel gears are used to overcome the limitations of straight bevel gears. As the name suggests, the teeth on a spiral bevel gear are arranged in the form of a spiral.
When two spiral gears come in contact, they do so gradually. This avoids impact loading of the teeth as the previous gear teeth pair that are now losing contact are still carrying some of the load. From this pair, the new mating pair assumes the load slowly. This makes the operation smooth and quiet.
It also increases the safe loading capacity of the gear. Thus, spiral bevel gears find use in highly demanding applications speeds greater than RPM for safe and reliable operation. Some of these applications are power transmission, car differentials, robotics, bow and stern thrusters in ships. Mitre gears are bevel gears with a speed ratio of An engaging pair will always have the same number of teeth. They transmit power between intersecting axes.
Mitre gears are used in machines to change the direction of rotation only. They do not cause a change in the shaft speed or torque. A mitre gear may be of straight or spiral type. Straight mitre gears offer the advantage of not having to deal with any axial thrust. But they come with the limitations of straight bevel gears. Spiral mitre gears produce axial thrust necessitating the need for thrust bearings. Mitre gears usually engage at 90 degrees. But they may be produced to mate at other angles as well.
If they mate at any other angle between 0 and , they are known as angular mitre gears. Most common range for angular mitre gears is between 45 and degrees. Hypoid gear resembles a spiral bevel gear but there are some marked differences. Unlike spiral gears, hypoid gear shafts do not intersect. The hypoid gear is placed offset to the crown wheel which is usually a spiral bevel gear.
This positioning of the hypoid gear results in greater contact when mating. This improves load-carrying capacity as well as the durability of the transmission system.
Another difference is the shape of the hypoid gear. The gear body is in the shape of a revolved hyperboloid. A cone forms when a right-angled triangle revolves around one of the edges that form the right angle. If we replace the hypotenuse which is a straight line of the right-angled triangle with a hyperbola and revolve it around the same edge, we get the hyperboloid shape.
This shape matches perfectly without any interference with the spiral bevel gear as the two mating gears are placed a little to the side.
Compared to bevel gears, hypoid gears achieve higher speed reduction due to their large contact ratio. The increased contact also permits higher load transmission while suppressing noise and vibration. The meshing is, however, complex and the production is also difficult. Hypoid gears are used in automotive differential systems. Hypoid gears bear some similarity to worm gear systems but they have certain advantages over them. Firstly, less sliding occurs, reducing power consumption.
Secondly, the offset between the two gears is less which saves space. Finally, both gears can be heat-treated which imparts higher rigidity reducing the size of gears used. In a worm gear drive, a worm engages with a worm wheel and motion transfer takes place. A worm gear resembles a screw and as it rotates it meshes with a cylindrical gear, sometimes also known as worm wheel.
This system is used to transfer motion between two non-parallel, non-intersecting shafts. Worm gears offer one of the highest gear reduction ratios. A unique characteristic of this gear drive is that the gear pair rotation can be locked. This is because the worm wheel cannot turn the worm gear if it is set at a certain angle.
However, the worm gear can turn the worm wheel at any angle. This property is utilized in applications that require self-locking mechanisms. Since the gear is curved, this angling causes the tooth shape to be a segment of a helix. Helical gears can be meshed in a parallel or crossed orientations.
At any instant the load on the helix gear is divided onto the more teeth of the gear, so there will be less deformation within time. Helical gears can be placed in such a way that their axis are in parallel or vertical. The disadvantage of those gears is the repulsive force caused by the helix structure of the teeth. This situation increases the frictional force between the teeth, to reduce this effect the teeth of the helical gears should be oiled.
Double Helical Gears : These are the gears that look like two mirrored helical gears joined together. The repulsive force for double helical gears are less than that of helical gears, since the gears are in V shape and the effect of the repulsive force is divided on each of the two sections of the V shaped teeth.
Therefore, the resulting deformative effect of the repulsive force is reduced. These gears are positioned in a way that their shaft axis are in vertical position.. Bevel Gears : The teeth of bevel gears may be like spur gears or they may be cut in a variety of other shapes.
Spur conical gears are used to transfer the motion within the shafts with intersecting axis. The degree between the shafts can be any degree but 0 and The gears having same number of teeth and a degree of 90 between their shafts are called miter gears. Zerol bevel gear teeth are curved along their length, but not angled.
Spiral gears have the advantages and disadvantages similar to helical gears. Crown Gears : Crown gears or contrate gears are a particular form of bevel gear whose teeth project at right angles to the plane of the wheel; in their orientation the teeth resemble the points on a crown. A crown gear can only mesh accurately with another bevel gear, although crown gears are sometimes seen meshing with spur gears.
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