Girth Gears

Designing

Buyer's Guide

Maintenance

Girth Gears: Product Code: AGG001 Product Specifications: Materials used in making girth gears: MS or Alloy Steel, Carbon Steel Standards: As per ASTM, BS, IS, AISI, SAE Module: Upto 60 Module Type: Spur Manufacturing Capacity: 1mtr to 10,000mm Outside Diameter Note: We also entertain custom requirments. » Send Enquiry

Girth gears are considered to be one of the most important component in the entire gear drive assembly. The highlighted feature of girth gears is that they are made in multiple segments. These segments are of two, four or eight equal sizes.

Designing Girth Gears
For designing Girth Gears and pinions, there are today several standards. The most common and popular standards are AGMA 321.05, AGMA 6004 F88 and ISO 6336. The two thing that forms the test of the Gear design are surface durability(pitting) and tooth bending strength. Both are tested by Hertzian fatigue stress and the Bending fatigue stress respectively. The image shows a very large Girth Gear that has a diameter of 8.8 meter used in a steel industry.

Buyer's consideration for Girth Gears
If you are opting for Girth gears for your production, the following points can prove to be very useful.

• Proper checking
  While zeroing on a girth gear supplier, it is vital to ensure that they have the requisite facilities for properly performing necessary checks. This can be the quality attributes like pitch (tooth spacing), profile, lead angle and other attributes. This would ensure the gear set functions in a proper fashion.
  
  
• Same Supplier
  It is imperative to have same suppliers for the pinion as well as the girth gear. This way it is assured that the pinion and the girth gear would mate properly at installation without any hitch. Not taking notice of this can result in unacceptable schedule delay.
  
  
• Availability of proper facilities
  It is critical to ensure that the supplier of the girth gear has the capacity for turning the diameters, precisely machine the splits and easily locate the alignment dowels.
  
  
• Cost analysis
  A complete cost analysis needs to be performed with attention to equipment and operating as well as maintenance costs.
  
  
• Structure Design
  The criteria for structure design of a gear along with material quality also needs to be considered thoroughly.

Path breaking Advancements in Girth Gear Materials Recently there has been remarkable advancements made in the Girth Gear Material. By using state-of-the-art full ring risering technology, castings are greatly enhanced Newer researches in material development is allowing designers to take advantage of more hardness and, therefore, increased ratings. Simulation programs are now used to verify proper solidification has taken place or not. Numerous examples are run for confirming that proper sizing of wedges, gates, and risers has been done. This has a remarkable effect on the casting quality, reduction in the foundry costs, and total elimination of casting failures. Another feature has been added to the cap of the girth gear technology with the introduction of finite element analysis. With this technology, it is now possible to calculate not only the stresses in the structure of girth gear but the gear's deflection can also be analyzed. Accordingly modifications needed in the pinion tooth can then be ascertained.

Other purchase Considerations
Besides the above general instructions some of the very important considerations with respect to the Gear and pinion of the Girth Gears are given in the following table.

Gears	Pinions
Face and involute contact	Face and involute contact
Surface finish	Surface finish
Quality number	Quality number
Chemical analysis	Chemical analysis
Ultrasonic checks	Ultrasonic checks
Magnetic particle checks	Magnetic particle checks
BHN number	BHN number
	Case depth

Maintenance of Girth Gears
The specific methods of maintenance of these gears are as follows:

• Stroboscopic viewing
  This is done during the operation of these Gears is operating. It gives the operator a clear picture of the actual condition of the gear.
  
  
• Infrared temperature measurements
  Infrared temperature measurements are also done during the these gears operation. It monitors the load distribution. It gives the operator a method to schedule and plan the specifics of any alignment, which may be necessary due to foundation shifts for example.
  
  
• Visual examination
  Visual examination is done of the teeth during the non operation hours for example during linear replacement.
  
  
• Proper Lubrication
  These gears need very sophisticated lubrication systems. Though we would never even think of running our car engines without lubricant, yet we are prone to doing so with Girth Gears. The following image shows the pitfalls of an improper lubrication.