Spiral bevel gear

Spiral Bevel Handedness, ANSI/AGMA 1012-G05

Zerol Handedness, ANSI/AGMA 1012-G05

A spiral bevel gear is a bevel gear with helical teeth. The main application of this is in a vehicle differential, where the direction of the drive carried by the drive shaft has to be turned through 90 degrees in order to power the wheels, propeller, etc. The helical design produces less vibration and noise than conventional straight-cut or spur-cut gear with straight teeth.

A spiral bevel gear set should always be replaced in pairs i.e. both the left hand and right hand gears should be replaced togeter since the gears are manufactured and lapped in pairs.

Handedness

A right hand spiral bevel gear is one in which the outer half of a tooth is inclined in the clockwise direction from the axial plane through the midpoint of the tooth as viewed by an observer looking at the face of the gear.

A left hand spiral bevel gear is one in which the outer half of a tooth is inclined in the counterclockwise direction from the axial plane through the midpoint of the tooth as viewed by an observer looking at the face of the gear.

Note that a spiral bevel gear and pinion are always of opposite hand, including the case when the gear is internal.

Also note that the designations right hand and left hand are applied similarly to other types of bevel gear, hypoid gears, and oblique tooth face gears.

Hypoid Gears

A hypoid is a type of spiral bevel gear whose axis does not intersect with the axis of the meshing gear. The shape of a hypoid gear is a revolved hyperboloid (i.e., the pitch surface of the hypoid gear is a hyperbolic surface), whereas the shape of a spiral bevel gear is normally conical. The hypoid gear places the pinion off-axis to the crown wheel (ring gear) which allows the pinion to be larger in diameter and have more contact area. In hypoid gear design, the pinion and gear are practically always of opposite hand, and the spiral angle of the pinion is usually larger than that of the gear. The hypoid pinion is then larger in diameter than an equivalent bevel pinion.

A hypoid gear incorporates some sliding and can be considered halfway between a straight-cut gear and a worm gear. Special gear oils are required for hypoid gears because the sliding action requires effective lubrication under extreme pressure between the teeth.

Hypoid gearings are used in power transmission products that are more efficient than conventional worm gearing.

Spiral Angle

Spiral Angle, ANSI/AGMA 1012-G05

The spiral angle in a spiral bevel gear is the angle between the tooth trace and an element of the pitch cone, and corresponds to the helix angle in helical teeth. Unless otherwise specified, the term spiral angle is understood to be the mean spiral angle.

• Mean spiral angle is the specific designation for the spiral angle at the mean cone distance in a bevel gear.

• Outer spiral angle is the spiral angle of a bevel gear at the outer cone distance.

• Inner spiral angle is the spiral angle of a bevel gear at the inner cone distance.

Spiral Angle Relationships, ANSI/AGMA 1012-G05

Comparison of Spiral Bevel Gears to Hypoid Gears

Hypoid gears are stronger, operate more quietly and can be used for higher reduction ratios, however they also have some sliding action along the teeth, which reduces mechanical efficiency, the energy losses being in the form of heat produced in the gear surfaces and the lubricating fluid.

In past eras of automotive manufacture, hypoid gears were typically used in rear-drive automobile drivetrains. However modern designs have tended to substitute spiral bevel gears to increase driving efficiency.

Hypoid gears are still common in larger trucks because they can transmit higher torque. A higher hypoid offset allows the gear to transmit higher torque. However increasing the hypoid offset results in reduction of mechanical efficiency and a consequent reduction in fuel economy. For practical purposes, it is often impossible to replace low efficiency hypoid gears with more efficient spiral bevel gears in automotive used because the spiral bevel gear would have to be much larger in diameter in order to transmit the same torque. Increasing the size of the drive axle gear would result in an increase of the size of the gear housing and therefore a reduction in the ground clearance.

Another advantage of hypoid gear is that the ring gear of the differential and the input pinion gear are both hypoid. In most passenger cars this allows the pinion to be offset to the bottom of the crown wheel. This provides for longer tooth contact and allows the shaft that drives the pinion to be lowered, reducing the "hump" intrusion in the passenger compartment floor. However, the greater the displacement of the input shaft axis from the crown wheel axis, the lower the mechanical efficiency.

Hypoid gear in a differential

Holographic Holographic Metamorphic Math Math a hyper plane defined by creating a nth dimensional spheroid with Radients instead of radiens. The Origin of the system is defined as Radients(radiens) = Pi, and the point of origin as z=((tan(x²) + tan(y²)) ²

The statement of claim of the new system is Pythagorean's Therom applied to a hyper plane. Ie the maping of x,y,z,t onto a three dimension space with the point of origin of z=((tan(x²) + tan(y²)) ²

Since the graph itself is holographic, the use of colors for the equations are necessary. Yellow as a base color for time where time is equal to y=e^tan(1)

Example:

 Pointcare conjecture solved by using virtual circles in a manifold space.  When mapped with new system, i -i 0 1 can be used in conjunction to simplify math.  Karnaugh map (K-map for short)

redefining the natural number line to -1,-pi,Delta,pi,1,2 where delta functions as a diferential between movement on the B axis and Pi

Note: Only viewable in 3D will not appear in standard 2d euclidean space.

See also

• List of gear nomenclature
• Offset (gears)