Support for gear design

KHK offers following gear design help.

Click here for Gear technical reference
This detailed gear design material (PDF) allows access to all commonly known gear technical data.
gear technical reference

Click here for Automated drawing of custom gears
Variety of gear drawings can be made by simply inputting parameters.
(spur gears, helical gears, internal gears, rack and pinion, bevel gears, worm gear etc)

Click here for Automated drawing of gears with secondary operations and their strength calculations
Use it by entering a KHK part number in the gray colored middle column on a stock gears page.
(At present, the secondary operations are limited to the features supported in the standard stock gears.)
strength calculation

Various elements of gear design and the conditions for determining elements

For design of gears, determine elements such as size, tooth shape, pitch, number of teeth, amount of profile shift, material, need for heat treating and/or grinding, choice for kind of tooth surface finish, amount of backlash, helix angle, helix direction, method of mounting on shaft, precision class, etc., the production process and the method of lubrication.

The main conditions for determining these elements are listed below:

– Dimensional considerations – mainly related to space restrictions of the machine design

  1. Center distance of the shafts
    Normally gears matching the center distance between the shafts is used, but there are occasions when profile shifting is used.
  2. Available space for mounting gears
    The decisions on tooth widths and outside diameters are affected by this. Normally various elements of mechanism within the interior of the machine are placed to utilize space efficiently. Therefore, these tooth widths and outside diameters can be restricted by the machine’s design itself.

– Amount and direction of force considerations – mainly related to the required performance of gears

  1. The amount of force transmission and the required strength of gears
    Chiefly conditions affecting bending and tooth surface strengths which are determined by material, pitch, pressure angle, profile shifting amount, tooth width, heat treating methods, etc.
  2. Direction of force transmission
    Affects the decision of tooth helix direction and type of gears (e.g. use of racks for linear motion).
  3. Desired speed ratio
    Determined by the choices of numbers of teeth.

– Usage and handling considerations

  1. Durability of gears
    Since it is mostly determined by the bending and tooth surface strengths, it influences the decision on material, pitch, pressure angle, profile shifting amount, tooth width, heat treating methods, etc. Also it affects the lubrication method.
  2. Related to the weight and maintainability
    Determines mainly the size, form, material (specific gravity), and method of shaft attachment.
  3. Related to noise and vibration
    Affects the decisions chiefly on precision grade, need for tooth grinding, use of crowning or end relief,
    material, amount of backlash and lubrication method.
  4. Related to shock at start and stop time
    Related to gear strength so that it is influenced by material, pitch, pressure angle, profile shifting amount, tooth width, heat treating methods, etc. It is also affected by the amount of backlash.

– Conditions concerning the manufacturing and economy

  1. Ease of production and possible utilization of available production facilities.
    Influenced by manufacturing method, size and many other elements.
  2. Manufacturing cost
    Affects choices of material, use of gear grinding, surface finish, precision class, etc.

– Environmental conditions of gear usage

  1. Temperature and humidity
    Influences the selection of material, kind of surface treatment, etc.
  2. Cleanliness and sanitary considerations
    Determines material, type of surface treatment, lubrication method, etc.

Related links :
Design of Plastic Gears – A page of Gear Technical Reference
Basic knowledge of mechanical design – A page of Basic knowledge of mechanical design
齿轮设计 – 中文页