Bevel Gear Design: Bevel Gear Dimension and Strength

Bevel Gear Design: Bevel Gear Dimension and Strength - Bevel gear is used to transmit power from one shaft to another shaft axes intersect. In general, the shaft bevel gear is formed at a 90 degree angle with a different number of teeth, but under certain conditions, this gear may be made at any size angle and tooth profile of the helix. Therefore, in addition also the bevel gear terms such as known:

1. Bevel gear, when two shaft are located at an angle with their axial lines intersecting at 90 degrees.
2. Miter gear, when the shafts are at right angles and the gears are of the same size
3. Angular bevel gear, when connecting the shaft angle is smaller or larger than 90 degrees.
4. Hypoid gear, when modified bevel gear having helical teeth.

Standard parameters of bevel gear are pitch diameter, module, number of teeth, whole depth, face angle, pitch angle, cutting angle and outside diameter. Parameter of bevel gear can be seen in the image below.

Determined of pitch diameter, module and number of teeth for bevel gear

Calculation of pitch diameter, module and number of teeth for bevel gear, miter gear and angular bevel gear of the same as the calculation of spur gear using the following equation: (Read more : calculation of spur gear)

Note:

D = Pitch diameter (mm)

M = Normal module

T = Number of teeth

Although calculation of pitch diameter, module and number of teeth for hypoid gear follow the calculation of helical gear using the following equation: (Read more: calculation of helical gear)

Note:

D = Pitch diameter (mm)

M = Normal module

T = Number of teeth

b = Helix angle or Hypoid angle (degree)

Determined of whole depth for bevel gear

Whole Depth is the height of teeth which is the sum of addendum and dedendum, or by the following formula:

Note :

H = Whole Depth (mm)

Ad = Addendum (mm)

Dd = Dedendum (mm)

x = Coefficient of tooth change

T1 = Number of teeth of gear

T2 = Number of teeth of pinion

Value of the coefficient of tooth change is different for bevel gears and pinion. Addendum to the pinion is greater than the bevel gear while dedendum to the pinion actually less than the bevel gear so that the value of x1 = x and x2 = - x.

Determined of pitch angle for bevel gear

If shaft angle (Σ) is smaller than 90 degree, so pitch angle for bevel gear and pinion can be calculated by the formula:

Note:

Δ1 = Pitch angle of gear (degree)

Δ1 = Pitch angle of pinion (degree)

If the shaft angle (Δ) is equal to 90 degrees, so pitch angle for bevel gear and pinion can be calculated by the formula:

Determined of face angle for bevel gear

Note:

Δ = Pitch angle (degree)

Δf = Face angle (degree)

θa = Addendum angle (degree)

Ad = Addendum (mm)

R = Pitch bevel length (mm)

D = Pitch diameter (mm)

Determined of cutting angle for bevel gear

Note:

Δ = Pitch angle (degree)

Δc = Cutting angle (degree)

θd = Dedendum angle (degree)

Dd = Dedendum (mm)

R = Pitch bevel length (mm)

D = Pitch diameter (mm)

Determined of outside diameter for bevel gear

Note:

Do = Outside diameter (mm)

D = Pitch diameter (mm)

Ad = Addendum (mm)

Δ = Pitch angle (degree)

That is a description about Bevel Gear Design: Bevel Gear Dimension and Strength. If you find misconceptions in the bevel gear formula, please provide the correction in the comment box.