Key Benefits

  • Dependable and easy to maintain for best availability
  • Rotating parts that bring your gear units back to life at the best price
  • Upgrade worn-out gear units quickly, with no civil engineering

Durable gear unit for ball mills with updated rotating parts

Drawing its name from the symmetrical torque split within the gearbox, the MAAG® GEAR SYMETRO™ is a two-stage gear central drive unit for ball mills with incredible durability. In fact, many of the original SYMETRO™ gearboxes still run cement production lines today – delivering more than 80 years of power and performance.

99% efficiency
Our multistage central drive provides reliable and trouble-free productivity
1926
Went the first MAAG® GEAR SYMETRO Gear Unit in operation – some of them still are
Nothing lasts forever, though, not even our SYMETRO™ Gear Units. If your MAAG® GEAR SYMETRO™ Gear Unit does eventually wear down, we have a range of rotating parts based on the newest manufacturing technology to bring it back to life. 

Elegant, efficient two-stage operation


The SYMETRO™’s free-floating balance wheel holds the key to its ability to split motor torque evenly to both transmission paths. The location of the balancing wheel is controlled through the unique combination of our gear unit’s:


  • guide rings
  • machined teeth positioned between the intermediate pinion and balancing wheel
  • corrected and marked tooth for timing
  • tension of the balance bearing
Our SYMETRO™ Gear Units deliver higher overall efficiency when compared to similar gear units from other suppliers – providing consistent power output for your ball mill with only two gear stages and a reduced number of bearings.

Upgraded rotating parts with TSHH technology


The TSHH technology used in the new SYMETRO™ Gear Units and rotating parts improves on the original units in several ways and ensures that our SYMETRO™ Gear Unit is ready to run at full capacity immediately after installation. TSHH stands for:

 

  • T - Transmission
  • S - SYMETRO
  • H - Case-hardened high-speed pinion
  • H - Case-hardened intermediate pinions

All of the SYMETRO™ pinions are case-hardened to a surface hardness up to HB 550 as well as ground with profile and lead modification. The wheels in our MAAG® GEAR SYMETRO™ Gear Unit are all through-hardened up to HB 360 and the ground teeth of the intermediate and balance wheels deliver increased surface finish quality. 

These manufacturing improvements to the SYMETRO™’s gearing optimise tooth contact at full load, minimise vibration and noise, and improve both overall operation and maintenance. The gear calculations are based on AGMA standards and the quality demands reflect ISO and DIN standards. Our SYMETRO™ Gear Unit is delivered complete with input pinion and torsion shaft with membrane plates – making it ready to run your ball mill at full capacity immediately after you install it.  

 


Easily renew your gear unit with rotating parts


Our SYMETRO™ rotating parts fit easily into your current gear casing and many of your existing parts can be reused if they are in reasonable condition. Once the SYMETRO™ rotating parts are in place, your mill can be started up at full load after a final check of the tooth contact, lubrication and safety systems. 
Set of rotating parts for SYMETRO gear unit with bearings
The total replacement of older, worn geared parts with new SYMETRO™ rotating parts takes less than two weeks – and reusing your existing foundation and bottom frame dramatically cuts down or completely eliminates civil engineering work. 

Tiptop shape with TSHH parts


Rotating parts using TSHH technology can be used for all existing MAAG® GEAR SYMETRO™ Gear Units, regardless of their capacity, size or type. Our special spare part and accessories program covers everything from complete gear sets to single components and additional monitoring kits – making it easy to keep your SYMETRO™ Gear Units in shape.

Our comprehensive documentation for the MAAG® GEAR Product Line allows us to supply spare parts for all gear units since 1926 – giving you confidence that your SYMETRO™ Gear Unit will be in good repair for decades to come.

Easy-to-maintain, dependable gear drive and value-add rotating parts

Dependable and easy to maintain for best availability
The reliable design of the MAAG® GEAR SYMETRO™ Gear Unit not only provides full access for visual inspection, it also delivers the highest availability of mill production with low vibration levels. All SYMETRO™ Gear Units and rotating parts use TSHH technology, which increases the AGMA service factor – and simplifies your installation and maintenance. 
Rotating parts that bring your gear units back to life at the best price
The TSHH technology used in SYMETRO™’s ground and case-hardened pinions and through-hardened wheels, means that the rotating parts can start at 100% load immediately after being installed in your mill. Optimised tooth contact delivers improved operations by reducing vibration and noise and reduces the need for servicing.
Upgrade worn-out gear units quickly, with no civil engineering
Our new SYMETRO™ rotating parts using TSHH technology are suitable for all existing MAAG® GEAR SYMETRO™ Gear Units. Installing our SYMETRO™ rotating parts into the existing gear casing of your ball mill takes less than two weeks and you can often reuse many of your existing parts and your current foundation – making set-up easy and eliminating the need for civil engineering works.

Gear unit and rotating parts for durability now – and into the future

Our multistage MAAG® GEAR SYMETRO™ Gear Unit for ball mills comes complete with:

 

  • Case-hardened high-speed pinion with bearings,
  • Two intermediate gear wheels shrink fitted onto case-hardened low-speed pinions with bearings,
  • New guide rings,
  • Balance wheel with side plates, and
  • Alignment tools. 
Red-hot SYMETRO intermediate pinion hanging in front of hardening furnace
The low- and high-speed couplings are flexible membrane couplings, with membranes made up of several thin steel plates. The membrane couplings of the SYMETRO™ Gear Units allow for minor angular deviation that compensates for small misalignments caused by thermal expansions in the gear and mill casings.Our state-of-the-art technology for heat treatment, gear cutting and assembly ensures that you can depend on all our SYMETRO™ gear parts – and rely on them for years to come. 

Our accessories take you further


We have developed a portfolio of units and devices to further improve the SYMETRO™ Gear Unit’s performance. You can retrofit these accessories to all existing units for greater safety, longer lifetimes and enhanced operational reliability.

 


Simpler maintenance with our barring device


Make servicing ball mills or gear units safer and more manageable with our TTVF-H barring device. The TTVF-H turns your mill at approximately 2% of regular operation speed and is able to lock the mill into a specified position. Using the barring device also ensures that you do not need to stop or start the main motor during maintenance.

 

Barring device for SYMETRO gear unit with electric motor

Lubrication for smooth operations


Our A/A-D/D lubrication system for all MAAG® GEAR SYMETRO™ Gear Units ensures fresh oil in the tooth meshes and bearings before and during operation. The A/A-D/D system requires only a slight modification of the piping to boost the filtration and cooling of your SYMETRO™ Gear Unit. We also have new electric oil level indicators to replace older, less-reliable switches in the oil trays. Improving the lubrication system of your existing gear unit and allowing it to function better in tough conditions, while also increasing the lifetime of the gearing and roller bearings.
Lubrication system with main pump, filter and cooler

Filtration and conditioning prolong the life of gear components


Reduce maintenance tasks and costs with our HDU fine filtration and conditioning unit for continuous offline filtering. Ensuring proper filtration within your MAAG® GEAR SYMETRO™ Gear Unit means less-frequent system cleaning and flushing, extended oil life with longer intervals between oil changes, and better equipment run factors – delivering all-around lower maintenance costs.  


Beyond a basic condition monitoring system


All of our gear units are equipped with unparalleled condition monitoring sensors. Normally, these types of sensors keep an eye on critical operating parameters like bearing temperatures, casing vibrations, etc. and trigger a mill shutdown in the case of exceedances.

Our condition monitoring system does much more. It lets you set up condition-based preventive maintenance that uses continuous monitoring and data analysis to detect wear and tear at an early stage. With this enhanced information, we help you plan maintenance and servicing in advance – reducing downtime and keeping your plant running smoothly. 
 

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