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Direct Drive Rotary Motors






 Conventional servo systems commonly have a mechanical transmission which   Which DDR Product is Right for Your Application?
 can consist of gears, gearboxes, belts/pulleys or cams connected between
 the motor and the load. With Direct Drive Rotary Motors, the mechanical   Gearbox Gearbox  Kollmorgen’s 70 years of electromagnetic and electromechanical design experience combined with our quality and service,
 transmission is eliminated and the motor is coupled directly to the load.   allowed us to refine and expand DDR motors into three product categories for easy installation, use, and short lead times:
 Servo   Servo
 Motor  Motor  Frameless DDR, Housed DDR, and the Cartridge DDR. This allows you to select the right DDR solution for your application.
 Why Use Direct Drive Rotary Motors?  Servo Motor and Gearbox

 Increased Accuracy and Repeatability    F  F                                                                           SER
 r  r                                                                                                                   V
 A “precision” planetary gearbox could have a backlash of 1 arc-minute. This can result in
 the load moving by 1 arc-minute with an absolutely stationary drive motor. Kollmorgen’s   Applications where the load rides on the motor’s bearings such as indexing or rate tables  O MO
 standard direct drive rotary (DDR) servo motors have repeatability better than 1 arc-second.   Direct Drive
 Motor
 Therefore, a direct drive motor can hold a position 60 times better than a conventional   Cartridge DDR                T
 motor/gearbox.                             This motor is the first in the industry to combine the space-saving and performance advantages of   ORS
 The increased accuracy of direct drive rotary motors results in a higher quality product out of   Frameless DDR motors with the ease of installation of a full-frame motor. Consisting of a rotor, stator, and
 the machine:                               factory-aligned high-resolution feedback device, the motor uses the machine’s bearings to support the
 • Print registration is more accurate  Improved   1  Gearbox  rotor. An innovative compression coupling engages the rotor to the load and the frame of the motor mounts
 Backlash
 • Cut or feed lengths can be held more precisely  Repeatability  to the machine with a bolt circle and pilot diameter just like a conventional servo motor, saving space and
 • Coordination with other machine axes is more accurate  Arc  design time and simplifying the overall system.          DIRECT DRIVE RO
 • Indexing location is more exact  Minutes 0  DDR
 Repeatability
 • Tuning issues due to backlash are eliminated  60 Times Better
 -1
 Higher Bandwidth
 Mechanical transmission components impose a limit on how fast a machine can start and   Any application with existing bearings  T
 stop and also extend the required settling time. These factors limit the possible throughput   Conventional Rotary     AR
 of a machine.  Servo with Mechanical  Housed DDR
 Transmission
 Direct drive rotary motors remove these limitations and allows for much faster start/  Increased Throughput            Y MO
 stop cycles and also provide greatly reduced settling time. Machine users of direct drive   DDR motors   The Housed DDR is a housed motor assembly featuring a factory aligned high-resolution feedback   T
 systems have reported up to a 2X increase in throughput.  – higher throughput   device and precision bearings, allowing it to function as the core of rotary indexing and rate
 – no start/stop limitations
               table applications. The system can also be used as a flexible indexer, providing programmable,           ORS
 Improved Reliability and Zero Maintenance  rapid indexing far exceeding the throughput and accuracy of conventional mechanical or variable
 Gears, belts, and other mechanical transmission parts break. By eliminating these parts and using DDR motors, the reliability of the machine is improved.   reluctance indexers.
 Gearboxes require periodic lubrication and/or replacement in aggressive start/stop applications. Belts require periodic tightening. There are no time-wear
 components in a direct drive motor and consequently they require zero maintenance.

 Fewer Parts
 With direct drive motors, all you need is the motor and the mounting bolts. This often replaces many parts including brackets, guards, belts, pulleys,   Applications where size and weight must be absolutely minimized
 tensioners, couplings, and bolts, resulting in:
 • Fewer parts on the BOM. Less parts to purchase, schedule, inventory and control, and less parts to assemble.  Frameless DDR
 • Assembly time of the servo drops from several hours with the mechanical transmission to several minutes with the DDR.
 • Reduced cost. Although a direct drive motor may carry a small price-premium compared to a motor/gearbox with the same torque, consider that there is   Frameless motors include a rotor and stator as separate components which are
 an overall cost reduction when eliminating the parts and labor of all the extra components required in a servo system with mechanical transmission.  integrated into, ride on the bearings of, and become a part of the driven load. Frameless
                                                      motors offer the most compact and lightweight DDR solution available. The KBM  and
                                                                                                        ™
 No Inertia Matching                                  TBM series are Kollmorgen’s Frameless DDR products. The KBM provides excellent
                                                      torque/volume with the use of a proprietary neodymium-iron magnet rotor structure and
 Servo systems with mechanical transmissions require inertia matching that limits the reflected load inertia at 5 to 10 times the motor inertia. If this limitation
 is not met, the system becomes difficult to control due to instability issues. Inertia matching limitations of mechanical transmission systems often force   skewed armature assembly. The KBM series is the first UL recognized parts set available
 machine designers to use a larger motor than would otherwise be required just to satisfy the inertia matching requirement.  on the market. This provides OEMs with the benefits of UL component ratings for easier
                                                      agency approval on their machines. The TBM frameless motor is a series of direct
 Such sizing conventions are not required with direct drive rotary motors. Since the motor is directly connected to the load, the inertia of the motor and the load   drive torque motors designed for applications that require high power in a small,
 become a common inertia. Therefore, no inertia matching is required when using DDR. DDR applications have run with inertia ratios greater than 11,000:1.
                                                      compact form factor with minimized weight and inertia.
 Reduced Audible Noise
 Machines with DDR motors have audible noise levels as low as 20 dB less than the same machine with a mechanical transmission.




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            www.kollmorgen.com                                                                                        95
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