Hydrostatic transaxle for lawn and garden equipment - Dana Corp. Spicer Outdoor Power Equipment Components Div.'s model 6400

Diesel Progress North American Edition, Jan, 1999

The recent GAFA garden trade show in Cologne, Germany, saw the launch of a new hydrostatic transaxle from the Spicer Outdoor Power Equipment Components Division of Dana Corp., which is expected to greatly enhance the productivity and driveability of lawn and garden and other horticultural and light agricultural equipment.

The new Spicer model 6400 transaxle enters the division's line of transmissions and transaxles for lawn and garden equipment in the medium-duty range, and will be produced at its works in Fredericktown, Ohio. It covers equipment powered by engines producing up to around 20 hp and is specifically aimed at ride-on vehicles with maximum gross weights of 850 lb., maximum weight over the axle of 550 lb. and running on tires with diameters up to around 20 in.

The transaxle is rated for continuous output torque of 205 Nm at output shaft speeds up to 130 rpm, and can accept maximum input speeds up to 3600 rpm. Output speed and torque are infinitely variable, and this overall 27.74:1 input reduction ratio comprises hydraulic reduction of 1.65:1 and mechanical reduction in the gear train of 16.81:1, Dana stated.

Major innovations on the new 6400 hydrostatic transaxle were described by Doug Krantz, product engineer at the Outdoor Power Equipment Components Division.

"In terms of its basic construction, our 6400 transaxle is a semi-integrated design, which means that its hydraulic section, comprising radial ball-piston pump and motor, is kept completely separate from the mechanical section that runs in a sealed-for-life grease bath," Krantz says. "Hence both sections are maintenance-free in terms of lubrication.

This two-piece design also makes the transaxle much easier to service and its parts much easier to replace," he added.

Freedom from maintenance, and extended life, are also addressed by an environmentally protected internal brake and internally sealed reservoir. In addition, Krantz notes, the transaxle has been designed to be both lighter and more compact than its competitors.

"In particular, we aimed to keep the height of the hydrostatic section down," Krantz said, "since this allows the OEM much greater freedom in designing center-rear grass discharge chutes on mowers."

However, the major user benefits of the Spicer model 6400 transaxle center on its smooth operation. "We believe the model 6400 sets new standards in this sector," Krantz continued. "To attain exceptionally smooth acceleration from standstill and during speed changes, the unit features our new Neutral Centering Control device, which automatically positions neutral for the OEM.

Specifications of the model 6400 hydrostatic transaxle.

Maximum Gross Vehicle Weight:               850 lb.
Maximum Weight Over Axle:                   550 lb.
Maximum Tire Diameter:                      20 in.
Maximum Continuous Output Torque:           205 Nm
Maximum Input Speed:                        3600 rpm
Maximum Output Shaft Speed:                 130 rpm
Overall Reduction Ratio:                    27.1:1
Hydraulic Reduction Ratio:                  1.65:1
Gear Reduction:                             16.81:1
Output Shaft Diameter:                      19 mm

"This is complemented by our Wide Band Neutral feature, which diverts hydraulic oil around the neutral position of the control valve to provide smooth acceleration and deceleration and, importantly, to prevent vehicle creep when in neutral. Plus, we include a mechanical tow valve to provide easier maneuverability of the vehicle when it's not in use."

Summing up, Mike Bowersock, general manager at the Spicer Outdoor Power Equipment Components Division, observed that the model 6400 hydrostatic transaxle had positioned Dana to assist OEMs in increasing equipment productivity and meeting ergonomic, environmental and safety requirements for lawn and garden equipment.