What is undercutting of gear?
Undercut – Gear Terminology The undercut of gears is also called deeper cutting and indicates the phenomenon of cutting the root of the gear deeper than the involute tooth curve. This can happen when there is interference between a tooth cutting tool and a gear or between the two meshing gears.
What is gear interference?
When two gears are in mesh it is possible that an involute portion of one will contact a non-involute portion of the other gear. This phenomenon is known as “interference” and occurs when the number of teeth on the smaller of the two meshing gears is less than a required minimum.
What are the methods to avoid interference and undercutting?
The Interference or undercutting in involute gears can be avoided…
- varying the centre distance by changing pressure angle.
- using modified involute or composite system.
- increasing the addendum of small wheel and reducing it for the larger wheel.
- all options are correct.
What is interference in involute gear and how it is prevented?
Interference can be eliminated by under-cutting of tooth. A portion of teeth below the base circle is cut off. When teeth are produced by this process, the tip of one tooth of a gear will not contact the non-involute portion of the tooth of other gear, hence, elimination of interference.
What is backlash in gear?
Backlash refers to the angle that the output shaft of a gearhead can rotate without the input shaft moving. Backlash arises due to tolerance in manufacturing; the gear teeth need some play to avoid jamming when they mesh.
What is the law of gearing?
The law of gearing states that common normal must always pass through the pitch point at the point of contact between a pair of teeth and the angular velocity ratio of all gears must remain constant throughout the gear mesh.
What is clearance in gear?
Clearance is the distance between the outside diameter of a gear and the root diameter of its mate. This margin compensates for the thermal expansion that occurs during operation, and prevents the top of a gear tooth from interfering with the root of its mating gear tooth.
What is Law of gearing?
What is gear slop?
In mechanical engineering, backlash, sometimes called lash, play, or slop, is a clearance or lost motion in a mechanism caused by gaps between the parts.
What is root and backlash?
Backlash is a play between tooth surfaces of paired gears in mesh. Mating gears also have a clearance (play) vertical to tooth depth. This is called Tip and Root Clearance (c), the distance between tooth root and the tooth tip of mating gears.
What is involute and cycloidal?
A cycloid (as used for the flank shape of a cycloidal gear) is constructed by rolling a rolling circle on a base circle. If the diameter of this rolling circle is chosen to be infinitely large, a straight line is obtained. The resulting cycloid is then called an involute and the gear is called an involute gear.
What is ring and pinion backlash?
Backlash (BL) determines how closely the pinion sits to the ring gear and how tight they mesh with each other. You want the BL to be neither too loose (poor mesh and driveline slop) nor too tight (excessive heat and gear wear).
What are cycloidal gears used for?
The majority of gears used in motion control applications — including spur, helical, and bevel designs — are involute gears. However, cycloidal gears are a good choice for motion control applications that require very high gear ratios (often greater than 100:1), low friction, and excellent wear resistance.
What is gear undercutting?
Undercutting is removing Some material from the base of gear tooth to avoid interference. Interference in gears would basically cause material wear and removal during operation, so we intentionally remove material by undercutting before operation.
Does undercutting of the pinion affect gear design requirements?
If undercutting of the pinion does affect the gear design requirements, then profile shifting or addendum modification techniques can be employed. As shown in Figure 1, a gear with 20 degrees of pressure angle and 10 teeth will have a huge undercut.
What is undercut in machining?
Undercut (manufacturing) Jump to navigation Jump to search. In manufacturing, an undercut is a special type of recessed surface. In turning, it refers to a recess in a diameter. In machining, it refers to a recess in a corner. In molding, it refers to a feature that cannot be molded using only a single pull mold.
What are the conditions for no undercutting of a spur gear?
In order to create the conditions for no undercutting of a standard spur gear, the following conditions must be met: When the pressure angle is 20 degrees, the minimum number of teeth for a spur gear to be free of undercutting is 17.