Welcome to KHK USA Metric Gears

What is a bevel gear?

      A cone-shaped gear having a cone as its pitch surface with gears cut along its surface is called a bevel gear. Two shafts crossing each other at a point are called intersecting shafts. Bevel gears belong to this type of intersecting shaft gears that are used to transmit rotational motion between them. The angle of intersection may be any angle, but it is generally a right angle.  The general efficiency of bevel gears is about 98 to 99%.

Kinds of bevel gears

      Straight Bevel Gears

            When the tooth is along the generating line of the cone (perpendicular line connecting the apex to the base circle), it is called a straight bevel gear.  Straight bevel gears are relatively easy to make and have simple shapes.

      Spiral Bevel Gears

            This is bevel gear with a curved tooth form. Compared to straight bevel gears, they have larger contact surfaces with resulting smoother, less noisy rotation.  They are suitable for high-speed heavy load operations but the production process is more difficult.  Also, the twist of the tooth form produces thrust load which requires attention. Spiral bevel gears are classified by the tooth cutting method and tooth form into Klingelnberg form (Germany) and Gleason form (US), but the Gleason form is now the mainstream.

      Miter Gears

            A pair of gears with the same number of gear teeth that transmits motion between the two right angle shafts are called miter gears.  They are often used to change the direction of rotation without affecting speed. Miter gears also come in straight and spiral teeth. There are also special angular miter gears which have shaft angles other than 90 degrees.

      Hypoid Gears

            Hypoid gears are sometimes used in automotive rear wheel drives and have cone shapes.  They could be considered to be a type of spiral bevel gears.  However, because the pinion shaft is offset from the large gear shaft, they are classified as non-intersecting shaft gears.

      Zerol Gears

            Zerol bevel gears are spiral bevel gears with a nearly zero spiral angle and can be considered to be straight bevel gears with bent tooth forms.  They have the characteristics of both straight and spiral bevel gears.  The thrust load that occurs with zerol gears are the same as the straight bevel gears so that it is possible to replace straight bevel gears with zerol gears without changing the bearing design.