Starter ring gear


Starter ring gear

A starter ring gear, sometimes called a starter ring or ring gear, is a medium carbon steel ring with teeth that is fitted on the periphery of a flexplate or flywheel of an internal combustion engine, mostly for automotive applications.

The teeth of the starter ring are driven by the smaller gear (the pinion) of the starter motor. The primary function of the starter ring is to transfer torque from the starter motor pinion to the flywheel or flexplate to rotate the engine to begin the cycle.

The starter ring gear is most commonly made by forming a length of square or rectangular steel bar into a circle and welding the ends together. There then follow various heat-treatmentlike normalising and tempering and machining operations, including the machining of the teeth and finally a heat-treatment operation. The teeth of the starter ring need to be hardened in order to increase their strength and resist wear. The normal hardness at pitch circle diameter is 45-55 HRC. The hardness at the root of the teeth is about 40 HRC and at 2 mm below root the hardness is 35 Hrc max. The body of the ring is generally left untreated.

Engines with manual transmission usually have a heavy flywheel, typically 5 to 10 kg of cast iron, with the starter ring gear shrunk onto the outside. This is done by heating the ring to around 200 °C to expand the ring which is then placed onto the flywheel, hold the ring gear with hydraulic pressure of 5 Kg/cm2 for 1 min and allowed to cool the ring gear.The starter ring is thereby firmly attached to the flywheel.

Engines with automatic transmissions instead have a pressed steel plate with the starter ring gear usually welded onto the outside of the plate.


Wikimedia Foundation. 2010.

Look at other dictionaries:

  • starter ring gear — A gear fitted around the flywheel that is engaged by teeth on the starter drive to crank the engine …   Dictionary of automotive terms

  • ring gear — [1] The large bevel, circular gear which is attached to the flange or carrier of the differential case. It meshes with the drive pinion on the end of the propeller shaft. [2] The outer gear in a planetary gearset. Also see flywheel ring gear. [3] …   Dictionary of automotive terms

  • flywheel ring gear — A gear on the outer circumference of the flywheel. The starter drive gear engages the ring gear and cranks the engine …   Dictionary of automotive terms

  • gear — Wheel like part with teeth cut into the rim. When one gear meshes with another gear, it causes the second gear to drive the other and in this way transmits power. When the gears are different sizes (different number of teeth on each gear) the… …   Dictionary of automotive terms

  • Starter solenoid — A starter solenoid (or starter relay) is the part of an automobile which relays a large electric current to the starter motor, which in turn sets the engine in motion.OperationThe starter solenoid receives a large electric current from the car… …   Wikipedia

  • Coffman engine starter — The Coffman engine starter (also known as a shotgun starter ) was a starting system used on many piston engines in aircraft and armored vehicles of the 1930s and 1940s. The Coffman system was one of the most common brands; another was the Breeze… …   Wikipedia

  • Automobile self starter — An automobile self starter (commonly starter motor or simply starter ) is an electric motor that initiates rotational motion in a car s internal combustion engine before it can power itself. History Both Otto cycle and Diesel cycle internal… …   Wikipedia

  • pinion gear — Pinion Gear: The smaller of two meshing gears. A pinion gear is used in a starter motor to engage the flywheel ring gear and also rides along the surface of the steering rack (a rod with grooves cut in it to mesh with the gear) See rack and… …   Dictionary of automotive terms

  • pre-engaged starter — A starter motor in which the solenoid operated pinion engages with a flywheel ring gear before the full electric current flows; an overrunning clutch enables the pinion to freewheel before disengaging, once the engine has fired …   Dictionary of automotive terms

  • Metal Gear Online — boxart released only in Japan Developer(s) Kojima Productions Publisher(s) Konami …   Wikipedia


Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”

We are using cookies for the best presentation of our site. Continuing to use this site, you agree with this.