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Speed reduction in a gear box is achieved using a worm and worm wheel. The worm wheel has 30 teeth and a pitch diameter of 210 mm. If the pressure angle of the worm is 20o, what is the axial pitch of the worm?
Consider the following statements: 1. In spur gears, the contact occurs abruptly on a line parallel to the axis, and the disengagement too is abrupt. 2. In helical gears, both loading and unloading are gradual, and therefore, these happen more smoothly and less noisily 3. When two gears mesh, any arbitrary shape of the tooth can be chosen for the profile of the teeth of any one of the two gears, and the profile for the other shall be obtained by applying the law of gearing. Which of the above statements are correct?
What is worm lead in worm and worm gear?
In a single threaded worm and worm wheel, the number of teeth on the worm is 50. The diameter of the effort wheel is 100 mm and that of load drum is 50 mm. The velocity ratio is
In worm gears, the angle between the tangent to the thread helix on the pitch cylinder and the plane normal to the axis of worm is called
Consider the following statements: In case of helical gears, teeth are cut at an angle to the axis of rotation of the gears. 1) Helix angle introduces another ratio called axial contact ratio. 2) Transverse contact ratio is equal to axial contact ratio in helical gears. 3) Large transverse contact ratio does not allow multiple teeth to share the load. 4) Large axial contact ratio will cause larger axial force component Which of the above statements are correct?
Among the following types of gears, which gears offer a refinement over spur gears?
Statement (I): Two  non-intersecting and non-parallel, i.e., non-coplanar, shafts connected by gears are called skew-bevel gears or spiral gears, and this type of gearing has a line contact the rotation of which about the axes generates the two hyperboloid pitch surfaces. Statement (II): A hyperboloid is a 3D surface formed by revolving a straight line about an axis (not in the same plane), such that every point on the line remains at a constant distance from the axis.
From an alloy, two specimens are machined and tested separately under tension and compression. The engineering stress-strain curves as well as the true stress-true strain curves for tension and compression are plotted in the same diagram. Identify the correct statements:
P. The engineering stress-strain curves in tension and compression are identical.
Q. The true stress-true strain curve in compression is lower than the true stresstrue strain curve in tension due to Bauschinger effect.
R. The true stress-true strain curve in tension is above the corresponding engineering stress-strain, curve.
S. The true stress-true strain curve in tension and compression are identical.
Which of the following is not true about worm gears?