Speed reducers enable switch from hydraulics

Edited by the Engineeringtalk editorial team Nov 16, 2004

Gear technology meets environmental challenge with switch from hydraulics to electromechanical operation.

Environmental concerns, energy consumption and the move to more fuel-efficient vehicles in the USA are among factors driving conversion of broach machines from hydraulic to electromechanical operation through the installation of gear technology developed by David Brown Engineering, a Textron Fluid and Power company.

The Federal Broach and Machine Company, located in the city of Harrison, Michigan, is a major supplier of broach machinery, tooling and integrated manufacturing systems.

Primarily serving the motor manufacturing, large truck, agricultural machinery and defence industries, Federal Broach has worked alongside a number of its customers to help them conform to new US Environmental Protection Agency guidelines that reflect concerns over leaks of hydraulic fluid from machine systems.

Textron Fluid and Power has collaborated with Federal Broach in developing a solution that substitutes electric motor and mechanical gearbox assemblies for the hydraulic components on the large helical broach machines.

The helical broach machine manufactures ring gear parts for automotive automatic transmissions.

Currently the strong business focus by the automotive industry is to move the standard for automotive transmission systems in the USA from a five-speed to six-speed transmission with the aim of improving fuel efficiency.

The three-dimensional functionality of the helical broach machines involves movement of the table to present the ring gear parts to the helical broach tools for cutting, while also rotating the individual broach tooling to perform the helix profile on the automotive part.

Two 8in centre distance HP double enveloping worm gear speed reducers and motor combinations drive planetary SKF screws, which raise and lower the table delivering up to 50t force to precisely broach the automotive gear components.

Two more 10in centre distance double enveloping worm gear sets create the 12.5t force required to turn each helical broach tool successfully.

The electromechanical operation of the helical broach machines removes the danger of hydraulic fluid spills and contamination while extending the service life of the machines and increasing their production capacity.

The conversion also removes need for a pit below the machine base to accommodate the hydraulic ram travel, simplifying installation and relocation of the helical broach units.

Two sizes of HP double enveloping worm gear speed reducers are specified for each electromechanical helical broach machine - with a 5:1 gear ratio for the 8in centre distance gear box and 40:1 ratio for the larger 10in centre distance double enveloping gear set.

The 8in CD cone drive units are supplied with hollow "keyless" shrink disc output shafts and specified with special thrust bearings on the output shaft.

The HP reducers are designed for applications that require extremely high torque and accuracy in a quiet, compact package.

The HP reducers have higher shock resistance, greater endurance to withstand heavy starting and stopping loads and can transmit two to three times as much torque as cylindrical worm gearing.

Precision is increased and backlash, chatter and noise are minimised, while interchangeability of parts means rapid manufacturing and delivery for customers.