Product Description

Rotary Kiln Spur Girth Gear Used in Construction Industry Machinery

Product Description

Girth Gears: Rotary kiln Girth Gear,ball mill Girth Gear
Girth Gears offered find extensive application in different industry sectors including in sponge iron plants, steel & cement industry, mining industry, wind mills as well as in other industry sectors. These are made available in module range of 10 Module to 70 Module and in minimum diameters of 100 mm to 15000 mm. Further, these comprise maximum weight of 70 MT single pieces. Here the range of hardened & ground gear boxes/gears comprise Worm gear boxes, Helical / Double helical gears/gearboxes, Helical-Bevel gearboxes, Planetary Gearboxes and others.

ZTIC Gear Cutting Machines include:
Ø16m CNC Hobbing Machine
Ø12m Gear Cutting Machine (Switzerland)
Ø10m Hobbing Machine (Germany)
Ø4m CNC High Speed Hobbing Machine (Germany)
Ø1.6m Horizontal CHC Hobbing Machine (Germany)
Ø5m CNC Profile Gear Grinding Machine (Germany)
Ø2.8m CNC Profile Gear Grinding Machine (Germany)
Ø1.25m CNC Profile Gear Grinding Machine (Germany)
Ø1m CNC Profile Gear Grinding Machine (Germany)
Ø0.8m CNC Profile Gear Grinding Machine (Germany)

With more than 1000 girth gears sold over the world CHINAMFG Gear is a leading supplier in the cement and mineral industry. And as member of AGMA (American Gear Manufacturers Association), we do actively take part in defining the standard for gear rating calculations and service factors. 
We provide girth gears in 3 different designs
Fabricated steel- forged ring- rolled plate  Cast steel 

Ductile (Nodular) cast iron  
Fabricated gears became more common in the past and are constructed with forged steel gear rim materials and electro welded body structure. The rings are manufactured from a whole block of high resistance alloy steel. After the rough machining of the ring, we carry out hardening and tempering heat treatment in order to improve the mechanical characteristic and therefore its relevant performance.  
Avantages of fabricated girth gears
The forged material structure excludes the risk of inclusions
Structure defects like gas holes, micro shrinkage, pin holes, hot tears, sand and slag inclusions are avoided
Hence, repair welding of the body structure and e.g. grinding of toothed areas is not required.
The fabricated manufacturing procedure excludes the need for patterns and risers
Rim material has higher hardness and higher strength than the material used for the underlying structure (i.e. web, gussets)
These features will reduce the lead time and costs. Fabricated manufacturing ensures a fast delivery.
This is especially beneficial in an emergency situation, where the existing gear rim is suffering from damage   


External teeth 
Maximum diameter: 16000 mm 
Toothed face width: 1700 mm 
Maximum module: 45 by hob 
Maximum module: 65 gear finishing cutter
Internal teeth 
Maximum Diameter: 6500 mm 
Maximum module: 25.4 
Toothed face width: 400 mm

ZTIC Gear invested in significant resources and achieved many innovations with pinions. The right combination of material, hardness and finishing between pinion and gear is crucial for a long lifetime of the installed equipment. We design and manufacture pinions to match every customers need, no matter how unique the situation might be. 

Quality assurance documents
The following reports are to be submitted to Quality Assurance:
a. Chemistry report
b. Physical report
c. Heat treatment documents
CITIC HMC  Q/HM 973.2-2007 Specification for Steel Castings for Grinding Mills
d. Ultrasonic inspection report (before and after repairs)
e. Magnetic particle inspection report (before and after repairs)
f. Dimensional report
g. Weld repair maps
h. Weld procedures and Procedure qualification record
i. Welder qualification
j. Nondestructive testing inspector qualification

Item Structural features Processing measure Test content
Girth Gear (1)GS42CrMo4Alloy Steel (corporate proprietary standards)
HB 220~240
(2)semi-structured, Y-Spoke 
(4) reasonable sealing and alignment structure of alloy steel (corporate proprietary standards)
(1) outer steel refining (R-H argon and vacuum treatment) 
(2) proprietary cold mold hanging sand technology to ensure the casting, the teeth dense 
(3) normalizing (proprietary technology) to ensure that the tooth surface hardness 
(4)rough hobbing, release time, repair the joint surface, then fine roll 
(5) proprietary homemade hob fine hobbing
(1)castings mechanical properties and chemical composition (internal standard) 
(2) roughing after sonic testing 
(3)semi-finishing, finishing after ultrasonic testing and magnetic particle inspection 
(4) tooth surface magnetic particle inspection, hardness test 
(5)tooth tolerance check 
(6) the factory assembly load test to check the accuracy of the size of gear

1. The technical requirements of a large CHINAMFG Gear ring:
1) is pretreated before normalizing surface hardening treatment, the hardness should HB210 ~ 250; mechanical performance are the ultimate strength Rb \ 690MPa, yield stress Rs \ 490MPa, elongation D5 \ 11%, reduction of area W \ 25% , impact toughness Ak \ 30J; teeth induction hardened, hardness HRC50 ~ 55; effective hardened layer depth \ 3 ~ 5mm.
2) overall ultrasonic flaw detection, internal quality should meet 2 requirements GB7233-87 standard requirements; tooth and fillet magnetic particle inspection, quality should meet 2 requirements GB/T9444-88 standards.
3) Note the casting is not rounded R5 ~ R10.
4) Tooth chamfer at both ends and 1 45b.5) by 2 and a half ring gear tooth width of each ring coupling along the edge of a whole ring made with high strength bolts, combined with the tooth surface must be at the bottom center.
2 large ring gear manufacturing process

2.1  of rough
Steel casting blank is provided by CITIC Heavy Machinery Co., Ltd. Heavy Forging plant, run by GB11352-89 standard specifies requirements for modeling according to the casting process, smelting, casting, hit boxes, cleaning, dressing castings;. During inspection and acceptance by the drawings and Technical requirements for steel blank
Checks, according JB/T6402-92 standards issued after acceptance
Down procedure.
2.2  roughing
Crossed by drawing and stay out allowance, alignment, connection, processing both inside and outside the circle, combining face milling, drilling and other processes.
2.3  Exploration injury
Overall ultrasonic flaw detection, internal quality should meet the 2 requirements of GB7233-87 standards.
2.4  normalizing pretreatment
Semi-ring pairs normalizing and tempering treatment, provide a good organization for subsequent surface hardening; press drawings deformation of the half ring gear inspection after heat treatment.
2.5  Machining
First 2 and a half ring is made with high strength bolts connecting the ring as a whole, the overall process by drawing a circle Quannei Wai teeth and upper and lower end, and then drawing and machining milling process requirements.
2.6  Elimination of processing stress
The overall ring annealed to eliminate stress.
2.7  overall ring surface hardening
IF along the alveolar tooth surface induction hardening, hardness HRC50 ~ 55, effective hardened layer depth \ 3 ~ 5mm.
2.8  Final inspection
First, the detection frequency quenching, the hardness after tempering ring gear cogging meets the requirements of the drawings; secondly, to detect whether the maximum outer diameter larger size D6944 as the deformation \ 3mm, the mechanical correction required until qualified; Thirdly, tooth and fillet magnetic particle inspection, quality should meet 2 requirements GB/T9444-88 standard requirements; Finally, according to the drawings and technical requirements for final inspection.

Company Profile

Our mode of transport is taken according to each country’s situation is different transportation, while our packaging, according to the latest customs situation, constantly updated, improved our packaging, we guarantee that you receive it within 3-7 working days to your product.
High quality service :
Best Service with after-sales service and consultation,we have an excellent customer service driven approach to our
business, unlike most sites we are consistently available via sales hotline, email, or MSN and always respond to
emails within 30 mins
Pre-Sales Service
• Provide details about the production procedure
• Assign engineers for installation and testing
Sales Service
• Customized solution designs
• Product rendering and steel structure drawing
•successful project examples and visits to our production and R&D base
After-Sales Service
• Two-year quality warranty with lifelong maintenance.
•Free guarantee repair (including labor and material): free repair service during the quality warranty period and reasonable charge for spare parts and maintaining service after the quality warranty period.  We will never exempt our responsibilities on product owned defects.  
•Responding time: CHINAMFG receiving user’s notification, we ensure 24-hour after-sales technical support.

After-sales Service: Twenty Four Hour Online
Warranty: a Year
Module Range: 10 Module to 70 Module
Certificate: ISO 9001:2008
Weight: Max 120 Mt Single Piece
Gear Cutting Machines: 16m CNC Hobbing Machine


Customized Request

spur gear

How do you calculate the efficiency of a spur gear?

Calculating the efficiency of a spur gear involves considering the power losses that occur during gear operation. Here’s a detailed explanation:

In a gear system, power is transmitted from the driving gear (input) to the driven gear (output). However, due to various factors such as friction, misalignment, and deformation, some power is lost as heat and other forms of energy. The efficiency of a spur gear represents the ratio of the output power to the input power, taking into account these power losses.

Formula for Calculating Gear Efficiency:

The efficiency (η) of a spur gear can be calculated using the following formula:

η = (Output Power / Input Power) × 100%


η is the efficiency of the gear system expressed as a percentage.

Output Power is the power delivered by the driven gear (output) in the gear system.

Input Power is the power supplied to the driving gear (input) in the gear system.

Factors Affecting Gear Efficiency:

The efficiency of a spur gear is influenced by several factors, including:

  • Tooth Profile: The tooth profile of the gear affects the efficiency. Well-designed gear teeth with accurate involute profiles can minimize friction and power losses during meshing.
  • Lubrication: Proper lubrication between the gear teeth reduces friction, wear, and heat generation, improving gear efficiency. Insufficient or inadequate lubrication can result in increased power losses and reduced efficiency.
  • Gear Material: The selection of gear material affects efficiency. Materials with low friction coefficients and good wear resistance can help minimize power losses. Higher-quality materials and specialized gear coatings can improve efficiency.
  • Gear Alignment and Meshing: Proper alignment and precise meshing of the gear teeth are essential for optimal efficiency. Misalignment or incorrect gear meshing can lead to increased friction, noise, and power losses.
  • Bearing Friction: The efficiency of a gear system is influenced by the friction in the bearings supporting the gear shafts. High-quality bearings with low friction characteristics can contribute to improved gear efficiency.
  • Load Distribution: Uneven load distribution across the gear teeth can result in localized power losses and reduced efficiency. Proper design and gear system configuration should ensure even load distribution.

Interpreting Gear Efficiency:

The calculated gear efficiency indicates the percentage of input power that is effectively transmitted to the output. For example, if a gear system has an efficiency of 90%, it means that 90% of the input power is converted into useful output power, while the remaining 10% is lost as various forms of power dissipation.

It’s important to note that gear efficiency is not constant and can vary with operating conditions, lubrication quality, gear wear, and other factors. The calculated efficiency serves as an estimate and can be influenced by specific system characteristics and design choices.

By considering the factors affecting gear efficiency and implementing proper design, lubrication, and maintenance practices, gear efficiency can be optimized to enhance overall gear system performance and minimize power losses.

spur gear

Are spur gears suitable for high-torque applications?

Spur gears are commonly used in a wide range of applications, including those involving high-torque requirements. However, their suitability for high-torque applications depends on various factors. Here’s a detailed explanation:

Spur gears are designed to transmit power and torque between parallel shafts. They have straight teeth that engage fully, providing efficient power transfer. The suitability of spur gears for high-torque applications can be evaluated based on the following considerations:

  • Load Distribution: Spur gears distribute the transmitted load over a larger contact area compared to other gear types. This characteristic allows them to handle higher torque loads effectively.
  • Size and Diameter: The size and diameter of the spur gears play a crucial role in their ability to handle high torque. Larger gear diameters provide increased torque capacity due to the longer lever arm and larger contact area between the gear teeth.
  • Material Selection: Choosing the appropriate material for the spur gears is essential for high-torque applications. Strong and durable materials, such as hardened steel or alloy steels, are commonly used to ensure the gears can withstand the high stresses and torque loads without deformation or failure.
  • Gear Design: Proper gear design considerations, such as tooth profile, module or pitch, and the number of teeth, can impact the torque-carrying capacity of spur gears. Design parameters should be optimized to ensure sufficient tooth strength and minimize the risk of tooth breakage or excessive wear.
  • Lubrication and Maintenance: Adequate lubrication is critical for reducing friction, wear, and heat generation in high-torque spur gear applications. Regular maintenance, including lubricant replacement and gear inspections, can help identify and address any issues that may affect the gear’s torque-handling capabilities.
  • Supporting Components: The overall system design, including the selection of bearings, shafts, and housing, should be considered to ensure proper support and alignment of the spur gears. Well-designed supporting components contribute to the overall torque capacity of the system.

While spur gears can handle high torque, it’s important to note that there are limitations to their torque capacity. Factors such as gear size, material strength, tooth design, and operating conditions can affect the maximum torque the gears can safely transmit without failure.

In some cases, other gear types such as helical gears or bevel gears may be more suitable for specific high-torque applications. These gears offer advantages such as increased load-carrying capacity, improved torque transfer efficiency, and reduced noise and vibration levels.

Ultimately, the suitability of spur gears for high-torque applications should be evaluated based on the specific requirements, operating conditions, and industry standards applicable to the particular application.

spur gear

What are the benefits of using a spur gear mechanism?

Using a spur gear mechanism offers several benefits in various applications. Here’s a detailed explanation of the advantages of using a spur gear mechanism:

  • Simplicity: Spur gear mechanisms are relatively simple in design, consisting of cylindrical gears with straight teeth. Their simplicity makes them easy to manufacture, assemble, and maintain. They have fewer components compared to other types of gear mechanisms, resulting in lower complexity and potentially reduced costs.
  • Efficiency: Spur gears exhibit high efficiency in power transmission. The teeth of spur gears mesh directly, resulting in minimal energy loss during transmission. The simplicity of their tooth profile allows for efficient power transfer, making them an energy-efficient choice for many applications.
  • Compactness: Spur gears have a compact design, making them suitable for applications where space is limited. They can be arranged in-line, parallel to each other, or at right angles using additional components such as bevel gears. This flexibility in arrangement allows for efficient power transmission in tight spaces.
  • Versatility: Spur gears are versatile and can be used in a wide range of applications. They are available in various sizes, configurations, and materials, allowing them to be tailored to specific needs. Spur gears can handle different torque and speed requirements, making them suitable for both low and high-speed applications.
  • High-Speed Capability: Spur gears can achieve high rotational speeds due to their straightforward design and direct tooth engagement. They are capable of transmitting power efficiently at high speeds, making them suitable for applications that require rapid motion or high rotational velocities.
  • Precise Positioning: Spur gears provide accurate positioning due to their precise tooth engagement. The straight teeth allow for precise control of rotational motion, making them suitable for applications that require precise positioning, such as robotics, machinery, and automation systems.
  • Cost-Effectiveness: Spur gears are often cost-effective compared to other gear mechanisms. Their simple design and ease of manufacturing contribute to lower production costs. Additionally, their high efficiency helps reduce energy consumption, resulting in potential long-term cost savings.
  • Reliability: Spur gears are known for their reliability and durability. The direct tooth engagement provides excellent load distribution, minimizing stress concentration and wear. When properly lubricated and maintained, spur gears can operate reliably for extended periods, making them suitable for demanding industrial applications.
  • Wide Availability: Spur gears are widely available in the market, with various sizes, materials, and configurations to choose from. This availability ensures easy sourcing and replacement of gears when needed. Additionally, spur gears have been used for many years and have a well-established design and manufacturing process, leading to a robust supply chain.

These benefits make spur gear mechanisms a popular choice in numerous industries, including automotive, machinery, robotics, aerospace, appliances, and more. Their simplicity, efficiency, compactness, versatility, and reliability contribute to their widespread use in a wide range of applications.

China Professional Rotary Kiln Spur Girth Gear Used in Construction Industry Machinery wholesaler China Professional Rotary Kiln Spur Girth Gear Used in Construction Industry Machinery wholesaler
editor by CX 2023-09-23


Plastic Spur Gears

As one of the plastic spur gears manufacturers, suppliers, and exporters of mechanical products, We offer plastic spur gears and many other products.

Please get in touch with us for details.

Manufacturer supplier exporter of plastic spur gears.