Bosch Rexroth Offers Hydrostatic Travel Drives
December 4, 2012—With output torques from 600 to 1,300 kNm and a dual motor configuration, Hydrotrac GFT-N hydrostatic travel drives from Rexroth allow faster travel speeds, along with proven performance and reliability, in mining excavators and crawler cranes. The Hydrotrac GFT-N travel drive is a three-stage planteary gear with pre-arranged spur gear specifically designed for mining excavators and track-laying cranes. With ouptput torques between 600 and 1,300 kNm and a dual motor configuration, the drive allows for faster travel speeds than single motor drive configurations by taking advantage of the faster speed rating of the smaller motor. The drives can be integrated as a complete unit into the undercarriage frame, with the sprocket mounted to the output side transmitting the required torque to the track. The offset motor mount also allows increased ground clearance.The compact, space-saving plantetary gear complies with operational strength requirements, including those specified in DIN 3990, ISO 6336, AGMA, GL and DNV, while also reflecting customary standard design regulations for proven performance and reliability. Rexroth hydraulic motors are integrated as flanged-on fixed or variable displacement units plugged into the gearbox. As a standard supply feature, the gearboxes come with one or two spring-loaded hydraulically released multiplate parking brakes attached on the input side. The parking brake torque suits the respective motor torque. Rexroth has incorporated design features into the Hydrotrac GFT-N travel drives that make installation easy, help ensure uptime and minimize maintenance. An axial mechancial seal arranged between the stationary and rotating gearbox sections prevents moisture and dirt from entering the drive, even under extreme operating conditions. In addition, maintenance is limited to regular oil changes, which can be made conveniently from the gearbox end cover.