1. Basic Gear Parameters
1.1 Number of Teeth (Z)
Definition: The total count of teeth around the gear's circumference.
Importance: Determines the gear's size and ratio.
1.2 Module (m)
Definition: A metric unit that specifies the gear tooth size.
Common Values: 0.5, 1, 1.5, 2, 2.5, 3, etc. (measured in mm).
1.3 Diametral Pitch (DP)
Definition: An imperial unit that specifies the gear tooth size. It is the number of teeth per inch of pitch diameter.
Common Values: 20, 24, 32, 48, etc.
1.4 Pressure Angle (α)
Definition: The angle between the line of action and the line tangent to the pitch circle.
Common Values: 14.5°, 20°, 25°.
Importance: Influences the gear's strength and noise characteristics.
2. Gear Geometry
2.1 Pitch Diameter (d)
Definition: The diameter of the pitch circle where the teeth theoretically engage without slipping.
2.2 Outside Diameter (OD)
Definition: The diameter of the gear's outermost edge.
2.3 Root Diameter (RD)
Definition: The diameter at the base of the gear teeth.
2.4 Addendum
Definition: The radial distance from the pitch circle to the top of the teeth.
2.5 Dedendum
Definition: The radial distance from the pitch circle to the bottom of the teeth.
2.6 Circular Pitch (p)
Definition: The distance from one point on a gear tooth along the pitch circle to the corresponding point on an adjacent tooth.
2.7 Tooth Thickness
Definition: The thickness of a gear tooth measured along the pitch circle.
2.8 Clearance
Definition: The distance between the top land of one gear and the root of the mating gear when engaged.
3. Gear Types and Their Specifications
3.1 Spur Gears
Characteristics: Teeth are straight and parallel to the gear axis.
Applications: Simple, low-speed applications without high load.
3.2 Helical Gears
Characteristics: Teeth are cut at an angle to the gear axis, forming a helix.
Advantages: Smoother and quieter operation compared to spur gears.
Applications: High-speed and high-load applications.
3.3 Bevel Gears
Characteristics: Teeth are cut on a conical surface, allowing gears to mesh at various angles, usually 90°.
Applications: Right-angle power transmission.
3.4 Worm Gears
Characteristics: Consist of a worm (screw) and a worm wheel (gear), enabling non-parallel, non-intersecting shaft transfer.
Advantages: High gear ratios, compact design.
Applications: Elevators, conveyor systems.
3.5 Rack and Pinion
Characteristics: Converts rotational motion into linear motion. The rack is a flat gear with teeth, and the pinion is a cylindrical gear engaging with it.
Applications: Steering systems, linear actuators.
4. Tolerance and Measurement
4.1 Gear Tolerance
Definition: The permissible limit of variation in gear dimensions.
Standards: AGMA (American Gear Manufacturers Association), ISO gear standards.
4.2 Measurement Tools
Gear Measurement Tools: Gear measuring machines, CMM (Coordinate Measuring Machine), micrometers, calipers.
Inspection Parameters: Tooth profile accuracy, pitch accuracy, runout, surface finish.
5. Example Calculation for a Spur Gear
For a spur gear with:
20 teeth (Z),
Module 2 mm (m),
Pressure angle 20° (α),
Step-by-step Calculation:
Pitch Diameter (d): mm
Outside Diameter (OD): mm
Root Diameter (RD): mm
Tooth Thickness: mm
Understanding these specifications and dimensions is fundamental in designing, manufacturing, and quality control of gears, ensuring they meet the necessary criteria for their intended applications.
About Zhejiang Toman Intelligent Technology Co., Ltd. (Toman)
Toman is a company that adheres to the strategic vision of to be the leader in the professional field, with the mission of innovation to drive customer value enhancement, and the business philosophy of WISE, ALWAYS KEEP STEP AHEAD. In operation since 2006, the company includes the complete range of gear hobbing machine, gear cutting machine, gear machining compound machine tools, gear shaving machine, automatic production units, automatic turning production lines, and MES manufacturing execution system, etc. TOMAN today, is recognised as an industry leader for machines in China.
Toman cutting machines:
CNC high precision gear hobbing machine, gear chamfering machine, gear shaving machine, gear hobbing machine with integrated chamfering station etc.
-Profitable -Intelligent -Accurate
Our machines are suitable for commercial vehicle gear, passenger vehicle gear, construction machinery gear, especially for the processing of new energy vehicle gear.
For more information about cnc gear cutting machines, please visit our website:
www.zjtoman.com
www.tomanmachines.com
For further information, please contact:
Sharon Gong
Master of Mechanical Engineering
Whatsapp/Wechat: +8613589398142
Mail: sharon@zjtoman.com
Skype: sharon.gong525