The realm of mechanical motion components is one inhabited by rail guides, slides, gearboxes, actuators and more. Many of the configurations are similar, and the fundamental mechanical aspects really haven't changed that much over the years, but don't be fooled into thinking that there isn't innovation taking place there.
Mechanics of any kind are likely to limit speed capabilities, but most motion systems require some type of mechanical coupling to the motor or final motion element, so manufacturers are taking steps to better couple those parts, and to improve any elements that affect wear and tear.
End users are increasingly asking for more configurable tools, where existing systems don't quite fit their applications. "Customization of these units is bubbling to the top," says Pete Castelli, engineering manager for Thomson Systems, which uses mechanical components such as linear guides and ball screws from sister companies to build pre-engineered systems for customers. Those customers are making more requests, he says, for their specific stroke, rail lengths, geometries and more.
Key to performance is being able to match motors more closely with the mechanical components, argues Nuzha Yakoob, Festo product manager, positioning. "Some companies only sell the mechanical actuator," she explains. "Other companies only sell rotary motors or servo motors. By being able to do both, we can integrate the two very easily."
Beyond that, innovations are taking place with bearings, trying to reduce the wear and tear that can slow a system down or even create catastrophic failure. "Performance really comes from the speeds and accelerations that you can attain from the linear motion technologies," notes Scott Carlberg, product marketing manager, motion products, for Yaskawa. "So you try and pick bearings that will allow you to maximize that."
Primarily that means having the least amount of friction as possible in the system. Yaskawa is even looking at air bearings for some custom applications, Carlberg says.
Thomson incorporates polymers into its bearings that create a spacer in between each ball in a circuit. It'fs part of a movement toward "flube for life," Castelli explains, in which customers need not worry about keeping bearings lubricated.
Linear thrusters push, pull or carry a payload for distances less than 1 m. They are suited to replace internally designed belt or linkage systems that convert rotary into linear motion. They provide velocity to 5 m/s and acceleration to 12 Gs. A washdown version is available.
Power drawbar holds cutting tool in the spindle taper with gripper fingers that are pulled into the taper with the spring pack. Loss or reduction in hydraulic pressure will not release the tool. The power-off design requires pressure applied to the hydraulic piston and transmitted through the rod to push the clamping sleeve down.
Ott-Jakob/Advanced Machine & Eng'g
Microslide linear actuator has 15 µm/step resolution and maximum load of 13 N with a 64 mm maximum stroke length. The slide load carriage is made from self-lubricating polyacetal and features a built-in clearance take-up mechanism for load rigidity during motion.
All stainless steel Original Line cylinders include 12 bore sizes 5/16-3 in. bore with stainless steel end caps, standard urethane wipers, PTFE-based rod and pivot bushings, and food-grade synthetic grease.
Sigma Trac SGT linear actuators have automatic motor recognition, and speeds to 5 m/s and acceleration to 5 Gs. A Large integrated cable carrier allows space for peripheral cables and hoses, and covers and additional accessories are available.
EGSL electric slides operate with linearity and parallelism to an accuracy of ±0.0006 in. for strokes to 11.8 in. The ball screw is enclosed, and slides are available in four slide-width sizes of 1.4, 1.8, 2.2 and 3 in.
ETH Series rod-style electric actuator cylinder has three profile sizes with either in-line or parallel motor mounting configurations. Design elements include Class 7 ball screw with ground nut, angular contact thrust bearings, ground and polished stainless steel thrust tube, and parallel timing-belt tensioning station.
W37/W47 Spiroplan right-angle gear units with aluminum housings are lubricated for life, and can be mounted in any orientation (except M4) with the same amount of oil. First-stage helical gearing and second-stage hypoid gearing combination provide high mechanical efficiency and low energy consumption compared with worm gear units.
400 Series Profile Rail Linear Guides are available in 4 m lengths with rail sizes 5–45 mm in 5 mm increments. They include double-faced ball track bearing arrangements with standard or ball cage carriages that use the same rail design. Guides are rated to handle loads 9800–129,500 N.
Zero-Max Crown right-angle gear drives with AGMA Class 10 spiral bevel gears and non-magnetic stainless steel shafts have precision hardened and ground ball bearings for speeds to 2,000 rpm. The internal gears are permanently mounted to the shafts with locking pins. Standard two- and three-way models have 1:1 and 2:1 speed ratios in shaft diameter combinations of 3/8, ½, 5/8 and ¾ in.
ACT linear motor actuator alternative to ball screws and belt drives has travel ranges 100 mm to 1.5 m, acceleration capability to 5 g, velocity to 5 m/s, maximum continuous force output to 270.7 N with a maintenance-free, direct-drive, zero-cogging motor and noncontact optical linear encoder.
Nitra pneumatic line of stainless steel, round body, non-repairable cylinders feature type 304 stainless steel bodies with double rolled-in construction with high-strength aluminum alloy porting ends. Single- and double-acting models are available with nose, pivot and double-end mounting options. Some models are available with magnetic pistons for position indication. Bore sizes range 7/16–2 in. Depending on bore size, available stroke lengths range ½–18 in.
Precision planetary gears for synchronous and stepper motors are single-stage for gear ratios i=3, 4, 5, 8 and 10, and have ≤8-15 arcmin backlash. The gears are also offered in two-stage or three-stage designs. The premium series provides backlash ≤1 arcmin as an option paired with high-output torques. The planetary gears are delivered fully mounted on 8LSA, 8LVA, 8JSA and 80MP series motors.
B&R Industrial Automation
Slimline-normal and slimline-long runner blocks replace ball rail with roller rail systems to increase the load capacity of the axis. Corrosion-resistant Resist CR version has a matte silver, hard-chrome-plated steel body. The line sizes range 25–55 in accuracy classes P and SP.
Camco RSD zero-backlash, cam-actuated drive can be used with both rotary and linear systems. It is compatible with a variety of industry-standard servo motors, and offers ratios of 4:1 to 18:1 in a single stage. Output options are large flange with through hole, 32 mm diameter shaft, external shrink disk for 30 or 40 mm shaft, and internal shrink disk for 30 mm shaft.
Infinity 1 roller screw actuator has an IP rating of IP64+ and possible IP68 (motor-dependent) via a hermetically sealed case. The enclosed integrated position transducer offers absolute position measurement in analog and SSI output. The integrated load and torque sensor offers absolute load measurement in analog mV output with no translating wires.
Series FGXS twin bore, precision table slides have a rail bearing system for smooth operation. Magnetic pistons and sensor mounting slots are standard. Optional sensors feature surge protection, polarity protection, LED indicator, and fast switching speeds. Options include adjustable stroke and shock absorbers, bores 8–25 mm, and strokes to 150 mm.
RLSS rod locks, Generation 2, with optional embedded engagement sensor deliver holding forces to 5,000 lb with low backlash. A clamping collar applies a 360° holding force around the cylinder rod. Models are CE-marked and RoHS-compliant.
Line of pneumatic Minimatic cylinders in stainless steel, brass, metric, corrosion-resistant and compact series are offered in 12 bore sizes with strokes to 40 in. Options include 304 stainless steel tubes for low breakaway, anodized heads for extra corrosion protection, sintered bronze bushings, U-cup piston seals, and accessories.
Clippard Instrument Laboratory
SLM and SLG rotary actuators with Class I, Div. 2 certification are suited for operating quarter-turn or multi-turn valves or shaft drive dampers. Directly coupled shaft-to-shaft, these actuators eliminate cumbersome mechanisms needed by pneumatics. To meet application requirements, the Class I, Div. 2 rotary actuators are also available with resolver feedback and handwheel options.