Posted to News on 20th Feb 2017, 00:00
High speed gearheads bring greater efficiency to go-karts
Electric go-kart manufacturer Rimo is bringing more efficiency and power to the racing ring thanks to the use of planetary gears. First test runs have highlighted the benefits of the SP+ High Speed gear units from Wittenstein, with the Rimo go-karts achieving pole position on the Nürburg Ring circuit. The cutting edge planetary gearhead has helped Rimo bring power and efficiency to the track.
Rimo designs and manufactures its go-karts in-house, and exports them go-karts worldwide, some of them being constructed with two 2.8kW motors, which drive the rear wheels individually. The gears have to fit into a very small space, and must withstand high speeds and high breakdown torques. Georg Roters, head of production, invited Wittenstein to a field trial, and the SP+ High Speed gearhead took pole position with ease.
The SP+ High Speed is a low backlash planetary gearhead with output shaft. The standard version is ideally suited for high positioning accuracy and highly dynamic cyclic operation. The SP+ High Speed is particularly well suited to applications with maximum speeds during continuous operation. Because the disc brakes and wheels are mounted directly to the output shaft, Wittenstein installed a special shaft. Also, the version of the gear produced for Rimo was specified for very high speeds. Wittenstein normally approves average drives speeds of 4500 revs/min, but for Rimo speeds of 6300 revs/min were tested – with a jacked up kart without load for a period of three hours.
The test run on the Ring confirmed the positive results shown in the endurance tests. Roters explained: “The High Speed gears get 20°C less hot than regular gears with oil lubrication, and that is good for both gear and kart.” A major advantage is also the better torque speed of the SP+ High Speed, because it goes easy on the batteries. This means the karts complete their laps using considerably less power. “We’re saving about a kilo in weight per gearbox,” Roters added. “In motorsport that is a huge difference.” The original motor sound, however, comes from loudspeakers as the alpha gears are a good deal quieter than the ones Rimo has used up till now. So nothing distracts from the authentic drive experience.
Enthusing about the experience of working with Wittenstein, Roters concluded: “Twenty-five electric go-karts will definitely be built with the SP+ gearheads.” He added that, alongside the performance, Wittenstein was able to guarantee shorter delivery times. “This means we don’t need to stock any inventory.”
