grand slam

Another Grand Slam for Sumitomo Gearboxes at T-Mobile Park!

Success Stories & Case Studies

The Importance of Quality Gearboxes and Proper Maintenance Practices to Ensure Longevity of Safeco Field's Retractable Roof System

Safeco Field, now known as T-Mobile Park, opened in July 1999 as the new home of the Seattle Mariners. It was designed with a retractable roof, which allowed fans to watch the game even in inclement weather. The retractable roof was driven by 96 Sumitomo gearboxes. After 24 years of service, a Sumitomo gearbox was returned for overhaul. The gearbox's condition demonstrated that selecting a quality gearbox and proper maintenance practices were essential for longevity.

The retractable roof is towed by 128 wheels powered by 96 ten-horsepower electric motors, which travel through rails and wheels similar to those of a train. The gearbox experiences uniform load under ideal conditions but can experience heavy shock loads due to weather conditions. The gearbox is installed outdoors, exposing it to various weather conditions, with temperatures ranging from 35 to 76 °F (~2 to 24 °C). The roof's deployment takes between ten and twenty minutes, with an estimated maximum operation time of three hours per day.

bevel buddy box

To select the appropriate gearbox, Sumitomo's load classification for selection was used to determine a service factor of 1.4 required for heavy shock load and intermittent duty applications. The selected gearbox, model KHFJS-D4165-R1-62, meets all the requirements. The gearbox operates at an output speed of 28.2 rpm, powered by a 10 HP motor. The gearbox is mounted horizontally using a flange and features Sumitomo's Taper Grip Bushing (TGB), which eliminates the need for precision machining of the driven shaft during installation.

When it comes to choosing a gear oil for ambient temperatures ranging from 35 to 76 °F (2 to 24 °C), it is recommended to use an ISO viscosity grade of either 100 or 150 cSt. Mobile SHC 627 oil with a viscosity grade of 100 cSt was utilized. To ensure optimal performance, regular maintenance practices were carried out, including checking the oil in all 96 gearboxes every six months. And checking for abnormal sounds, odors, and leaks each time the roof was deployed, and addressing issues promptly.

The intermittent nature of the roof's operation helps prolong the lifespan of the gearbox. However, when the roof is operated in bad weather conditions, the load distribution among the gearboxes can put a strain on them. Maintenance practices play a vital role in the gearbox's longevity. Sumitomo gearboxes require regular oil changes using the recommended oil type. The staff at Mariner's stadium discovered a couple of leaking gearboxes after 24 years of operation. A preventive inspection was recommended by Sumitomo's Sales team to avoid gearbox failure during service. The inspection and overhaul were performed by the Sumitomo Aftermarket team.

In conclusion, the Sumitomo gearbox used in T-Mobile Park's retractable roof is an excellent example of the importance of selecting quality products and careful consideration of all factors, including operation and maintenance practices. The gearbox's condition after 24 years of service shows that with proper maintenance, the high quality and workmanship of Sumitomo gearboxes can operate for years.

About Sumitomo Bevel BuddyBox Gearmotors

Sumitomo Drive Technologies has been trusted for over 130 years to provide quality products and innovative solutions to help our customers solve their complex challenges. This rich history has made us a leading manufacturer of gearboxes, gearmotors, speed reducers, inverters, and control products in a wide variety of applications for leading brands around the globe. Brands count on our industrial gearboxes and speed reducers in every industry, from Food & Beverage to Mining to Parcel Handling. Gearbox support from Sumitomo doesn't end after installation. Our experienced Aftermarket specialists are always available to handle gearbox repair, gearbox maintenance questions, and anything else you need for your operation.

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