What is the definition of a standard gear?
2 Answers
Standard gears refer to gears with parameters that all comply with standard values, and standard gears for different purposes are manufactured according to different standards. Standard gears are often used as reference samples for producing gears or for calibrating measuring instruments. Standard gear identification: All standard gears should be marked with the tool number, sequence number, part number, optimization development stage, set sequence number, and the backlash of the mounting distance relative to the standard control master gear (MCG) using vibration etching. Non-working standard gears: This standard gear is named the "silver gear." The standard gear (MG) is a "non-working" standard gear, used only for inspecting the tooth contact pattern and backlash of the inspection gear (IG).
When I first started as a maintenance apprentice, my mentor emphasized that standard gears are those with all dimensional parameters strictly complying with national standards, including tooth thickness, pitch, and tooth height, which must be precisely accurate. The most critical indicator is that the tooth thickness and groove width on the pitch circle must be strictly equal, and the pressure angle must be uniform, typically set at 20 degrees. Such gears must be manufactured using standard hobs or milling cutters, with tolerances controlled within a very narrow range. If non-standard gears are used instead, gaps or collisions will occur when two gears mesh, causing immediate abnormal noises in the gearbox. Last time, the shop encountered a case where a car owner used aftermarket non-standard gears, and the teeth broke after just 3,000 kilometers. The key point is that standard gears ensure any two gears of the same specification can be interchanged during installation, which is crucial for batch repairs of automotive components.
