Selecting and Applying Robot Flange Servo GearheadsJune 04, 2018
Precision gearheads play a critical role in motion-control applications where torsional stiffness, high torque and low backlash are of crucial importance. Often paired with servo motors, the gearheads are used to balance inertial loading conditions, increase torque and reduce motor speed — making them a useful mechanical interface for a wide range of transmission components, including pulleys, drums and cams.
In recent years, the use of gearheads with flanged outputs has increased significantly. These gearheads enable the machine being driven to mount directly to the flange, which eliminates the need for a flexible coupling.
Selecting the proper flanged output gearhead can be a difficult undertaking that requires consideration of a multitude of variables. The remainder of this article aims to simplify that task by outlining four different gearing solutions — each of which provides design engineers with a range of housing and performance options depending on the unique characteristics of their application.
Planetary gears consist of a sun gear, which is installed on the central axis. The sun gear is surrounded by multiple planetary gears and revolves on the axis by means of an internal gear. The revolution of planetary gears is translated into rotation of the output shaft by carriers. Planetary gearheads are designed to multiply torque and reduce motor speed by a factor of the gearhead ratio, which allows the motor to operate more efficiently. The inertia reflected back to the motor is reduced for increased stability.
The benefits provided by rotary flange servo gearheads can be leveraged in a wide variety of applications. Sesame PGF and PHF Series rotary flange helical bevel planetary gearheads, for instance, enable machine builders to use smaller, less expensive motion-control packages. The gearheads are ISO 9409-1 compliant and provide different performance levels to satisfy the full range of motion control in end-of-arm tooling applications, rack and pinon gearsets, waterjets, CNC machines, surveillance systems, medical devices and laser cutting machines.
Right angle worm reducers transmit power using a threaded worm and a wheel that meshes with the worm. The reducers feature an output shaft that is at a 90-degree angle to the motor shaft, which means that most of the gearhead housing and the entire motor housing, are parallel to the side of the machine. This results in a smaller machine envelope, which is advantageous in dynamic cyclical and speed control servo applications where space is limited.
Right angle worm reducers, like the Girard Dynabox, can help OEMs reduce costs by replacing bevel planetary gearheads. These worm reducers feature optimal gearing, high efficiency (94 percent for the 10.25:1) and are available in three (<1, 5, and 10 arcmin) backlash levels to satisfy a variety of applications, including those related to robotics, packaging machines, press feeders, printing machines and medical systems.
A hypoid gearhead is a conical gear designed to transmit power between skew gear shafts, where the tooth trace is curved. It is offset from the gear center, allowing unique configurations and a large diameter shaft. Teeth on a hypoid gear are positioned between the bevel gear and the spiral pinion, and are capable of achieving high strength and efficiency.
The Tandler Hypoid is an example of a hypoid gearhead that offers high performance and load connection versatility for high cycle servo driven applications. It is available in ratios from 5:1 to 15:1, depending on size, and provides compact torque multiplication in a common size. Applications of the Tandler Hypoid are wide ranging and include aerospace and defense, factory automation, material handling, machine tooling, packaging, biomedical, printing and robotics.
The primary function of a cycloidal reducer is to decrease the speed of an input shaft by a specific ratio. The reducer’s input shaft drives eccentric bearings that in turn drive the reducers in a cycloidal motion. The perimeter of the reducer is geared to a stationary ring gear and features a number of roller pins placed through the face of the reducer, which drive the output shaft as the unit rotates.
Spinea TwinSpin high-precision cycloidal reducers are designed for applications requiring a high reduction ratio, kinematic accuracy, low lost motion, high moment capacity and stiffness of a compact design with a limited installation zone and low mass. The reducers are available in a variety of ISO 9409-1 compliant configurations and have become a popular gearing solution in medical (dental milling machines and surgical robots), defense and security (pan-tilt surveillance cameras) and industrial robotics applications.
The Importance of Consulting with a Qualified Provider
Selecting the proper flanged output gearhead for a given servo application is an important decision that can have lasting impacts on efficiency, maintenance and operational costs. As the process for identifying the optimal gearing solution can be complex, consulting with a qualified provider is critical.
DieQua Corporation offers a broad range of gearboxes, gearheads and speed reducers available from a single source, along with the know-how to select the appropriate solution for your application. For information regarding products, or if you need help overcoming a power transmission or motion control-related challenge, contact one of their qualified experts.