MH Series

The MH Series are medium pressure hydraulic cylinders rated for 675 to 1500 psi (depending on bore size). The TAS Series Steel Pneumatic Cylinders are rated for 250 psi air and 400 psi hydraulic (with TH option). Both models are available in bore sizes 1.50”, 2”, 2.50”, 3.25”, 4”, 5”, 6” and 8”.

TAS Series

Standard features include a heavy-duty rod wiper, seals, wear band, chrome plated I.D. tube and more. Rod locks, stop tubes, center supports, stainless steel piston rods and high impact pistons are also available as performance options. Accessories include clevis, pins, mounts and alignment couplers, with up to a 5” thread size.

TRD Manufacturing
www.trdmfg.com

Bimba Manufacturing
www.bimba.com

The BLDC model is only 2.5 in. long, is available with optional logic speed control interface and features low EMI/RFI. The pump is maintenance-free, very quiet, and exhibits low vibration, low current and power consumption, making it ideal for mobile, battery-powered applications. All standard KNF pumps can be customized to meet specific OEM performance requirements. It is suitable for use in medical and analytical instruments, ink-jet printers, and pneumatic supply functions for prosthetic devices and ergonomic furniture.

www.knf.com

The Type 567’s double eccentric off-center design allows the disc to completely disengage from the disc seal, even when partially open. This separation between disc and seal reduces friction and wear for longer service life and minimizes maintenance compared to non-eccentric valves. Additionally, the double eccentric design requires only about half the torque of a traditional boot design, which also reduces wear on the disc seal to further enhance product life. Other advantages of the design include easier manual operation, compatibility with smaller actuators for reduced installation cost and better protection against pressure surges.

These butterfly valves weigh approximately 50 percent less than comparable metal butterfly valves thereby providing easier and faster installation and lower costs. The new large dimensions provide high nominal pressures for increased operation safety. Pressure ratings at 70F are 90 psi for sizes14 to 16 inch, 75 psi for size 18 inch, and 60 psi for sizes 20 to 24 inch. Other features include industry-standard ISO flange mount for easy electric or pneumatic actuation, bi-directional capability and hand wheel. The valve is available with either EPDM or FPM seals, 304 or 316 stainless-steel stem and a Polypropylene body.

www.us.piping.georgefischer.com

The Series 3MSV Compact 3-Way Ball Valves are the perfect choice for directional control of fluid in instrumentation and process systems. The micro finished ball and PTFE seats ensure quality seal and easy operation. The straight through flow path design allows for minimal pressure drop. The valve body comes in either brass or 316 stainless steel, offering a variety of options. Blow-out-proof ball and stem provides extra durability and safety in the event of over pressure.

www.dwyer-inst.com

These valves are engineered with higher pressure ratings for AC and DC operation that enable original equipment manufacturers to achieve higher performance from their products. In addition, with the modular product architecture, a Web-based configuration tool, online ordering, and the ASCO Today guaranteed same-day shipping program, customers can rapidly configure and purchase an 8262/8263 or 8314 Series valve specifically for their application and receive it the next day.

The 8262/8263 Series valves come in brass and stainless steel constructions with 1/8-inch, 1/4-inch, and 3/8-inch pipe sizes and are used to control the flow of air, water, light oil, and specialty media such as cryogenic fluids, ammonia, oxygen, and liquid propane. The 8314 Series valves come in brass and stainless steel constructions with 1/8-inch and 1/4-inch pipe sizes and are used to control the flow of air, water, and light oil.

The online configuration tool allows a customer to quickly build a valve to meet a set of specific requirements. It then displays the list price, availability, 3D CAD drawings, and specifications for the configured product. The configurator generates an order code for the valve that permits an immediate online purchase, plus greatly simplifies the reordering process.

www.ascovalve.com

Both models feature robust PTFE diaphragms and valves for optimal chemical resistance. The ME1C features a full fluoropolymer flowpath, for a complete chemistry-design pump. An optional vent control valve with dial gauge enables variable fine adjustment of the pumping speed.

www.brandtech.com

Thanks to its high level of modularity, the new HF02-LG can be integrated in a wide variety of automation concepts.

The HF02-LG series from Rexroth rounds out its standardized range of HF valve manifold systems with a weight-optimized base plate valve featuring high flow rates. The dependable HF family is now available with flow rates of 0.4Cv, 0.7Cv, and 1.4Cv and can be actuated with just one bus connection for all series.

The uniform connection technology for Rexroth valve manifold systems simplifies integration of pneumatics in a wide variety of automation concepts. Thanks to its modular design, the system enables use of multiple plugs and connections for all common field buses, with and without I/O signal processing and supports an integrated Drive & Diagnostic Link. The uniform interface for common field bus control (B-design) permits a simple and clear combination of various valve manifold systems, as well as standardized programming.

The new HF02-LG valve manifold system benefits from a free selection of connection technology. With a flow rate of 0.4Cv with a valve width of 20 mm, the system can accommodate up to 16 valve positions in one unit. An exceptionally modular design makes it possible to change the electrical controller without having to disassemble the valve manifolds. Electrical linking with other valve manifold systems, such as the HF03-LG and the HF04-XF, or individual valves, is simple using Rexroth’s module extension.

Robust parallel plug connectors in the base plates facilitate conversion of an HF02-LG valve unit and the plug-in valve makes it possible to exchange valve functions quickly and easily. Another special feature is that the customer can convert the pilot from an internal pilot control to an external pilot control directly on the left end plate.

The HF02-LG provides all valve functions: 2 x 3/2, 5/2, and 5/3. Dual-pressure operation is possible using separate exhaust connections for channels 3 and 5. Pressure zones can be limited to one valve. In principle, the valve manifold system has been designed for an internal working pressure of 36 to 145 psi and can be operated in a temperature range of 32 to 122°F. Up to 32 coils can be actuated with the 44-pin D-Sub high-density plug.

Rexroth provides a user-friendly configurator to assist designers who would like to integrate this valve manifold system in their installation. This online tool lets you easily configure valve units with all their accessories and displays them with a pneumatic circuit diagram or dimensional drawing. The latest enhancement: The user can download the configured unit as a 3-D PDF in which the unit can be rotated on the screen and viewed from all sides.

The HF02-LG valve manifold system is ideal for applications requiring a high level of modularity, such as in machine tools, special-purpose machines, welding technology, or polymer processing.

www.boschrexroth-us.com

Roller screw actuators have several advantages over hydraulic or pneumatic actuators for many applications, especially those involving heavy loads and fast cycles. For example, the controls are simpler, eliminating the complex system of valves, pumps, filters and sensors that make up hydraulic and pneumatic systems. Other benefits include a small system footprint, long functional life and low maintenance requirements. And because roller screw systems don’t require high-pressure fluid, they reduce noise levels and are not subject to potentially hazardous fluid leaks.

inverted roller screw mechanism Rollers screws come in two basic kinds of configurations; the inverted roller screw mechanism, top, and the standard configuration roller screw, bottom.

Roller Screw Technology
Roller screws convert rotary torque into linear motion, similar to acme screws or ball screws. But roller screws can turn considerably faster and cycle more frequently than both acme and ball screws, making them an ideal fit for demanding, continuous-duty applications. Similarly sized roller screws are more efficient than acme screws and can carry larger loads than ball screws, handling loads up to 779,000 lbf.

The difference in performance is due to the design for transmitting forces. The number of contact points in a ball screw is limited by the ball size. In roller screw systems, multiple threaded rollers are assembled in a planetary arrangement around a threaded shaft, which converts a motor’s rotary motion into linear movement of a shaft or nut. The rollers feature radiused flanks that deliver point contact, similar to balls on a raceway, with only the radius near the point of contact included as part of the profile. This design allows a larger radius with additional contact points to fit into the existing space, lowering the stresses within the system and lengthening its functional life. Because the number of contact points is greater, roller screws have high load-carrying capacities, as well as improved stiffness. This typically means that a roller screw actuator takes up less space in order to meet a designer’s load requirement than a similarly sized ball screw.

Roller screws are designed to have larger radii at the point of contact, meaning that more contact points will fit within the same relative space. This lowers stresses and lengthens functional life compared to a comparably sized ball screw system, top.

High load capacities mean that roller screws have some major advantages in service life. For instance, in a 2,000 lbf average load application applied to a 1.2 in. screw diameter with a 0.2 in. lead, a roller screw will have an expected service life that is 15 times greater than a ball screw. Typical ball screw speeds are limited to 2,000 rpm and less due to the interaction of the balls colliding with each other as the race rotates. In contrast, the rollers in a roller screw are fixed in a planetary arrangement by a journal and gears at the ends, so they do not have the same speed limitations. Hence, roller screws can work at 5,000 rpm and higher, producing comparably higher linear travel rates.

Versatile nut options let you balance between backlash and load capacity demands and cost trade-offs. Some common nut configurations are the single nut, split nut and double nut designs. The most common configuration, the single nut, has a long service life and low backlash under 0.001 in. In split nut designs, the nut is split transversely and a precision-ground spacer sits between the front and back halves. The split nut configuration effectively eliminates backlash and also reduces the dynamic load rating by about 38%. As the name implies, the double nut arrangement uses two nuts preloaded against each other on a single screw. This design offers similar life expectancy as a single-nut design as well as decreased backlash, but typically costs more than a single-nut configuration.

Roller Screw Size Specification
Roller screw variables include the diameter, lead and sealing. When preparing the component specification, be sure to take into consideration the budget, maximum linear speed, maximum load, maximum stroke, necessary precision level, tolerance to backlash, the contaminants present and the needed level of protection.

A few key calculations help determine the ideal parameters for an application. For example, roller screw nut speeds cannot exceed their mechanical speed limit, which is dependant on the screw diameter and the lubrication method. Systems lubricated with oil should not exceed 140,000/d_o, while grease-lubricated roller screws systems shouldn’t surpass 90,000/d_o.

In high-speed roller screw applications, the roller screw shaft typically sets up natural frequency vibrations, which should be taken into account by calculating the critical speed. This speed is determined by the screw diameter, length, loading direction and bearing arrangement. The rotational speed of a roller screw should be kept below the critical speed, defined as:

n_crit = 86.4 x 10⁶d_of_s / l²

where:

n_crit = critical rotational speed under zero axial load (rpm)
d_o = screw diameter, in. (mm)
fs = support bearing factor
l = screw’s length, in. (mm)

Another phenomenon to avoid is buckling. Buckling occurs when the compressive load on a screw’s shaft is too great for its diameter. The buckling force is determined by the screw length, diameter and type of bearing supporting the screw. The compressive load should be less than the buckling force, defined as: F_b = 81.3f_bd_o⁴ / l²

where:

f_b = buckling force, kN
F_b = buckling force bearing factor

Another factor to consider is the motor size. A motor is selected by calculating the required torque as a function of load on the system and lead of the roller screw and comparing it to available motors and power transmission components. For applications that require a specific motor, roller screws with a lower or faster lead, belt or gear reductions can be configured into the system.

Protection and Maintenance
While correctly specified and maintained rollers screw systems can still fail from metal fatigue or abrasion of the thread flanks, other failures can typically be prevented. For optimal performance and life, roller screws, like other lead screws, should be well lubricated and must tolerate contaminants including abrasives, metal chips and non-lubricating fluids.

Although the friction created by the rolling screw design is minimal compared to sliding friction, it can still cause heat build-up, which can eventually lead to a costly failure. Lubricants should be used to dissipate heat in order to avoid wear and premature failure. In general, roller-screw life can be increased by regular grease and oil replenishment. Maintenance intervals depend on the screw size and operating conditions. Typically KP (DIN 51825) consistency two bearing grease should be applied. Some applications with higher duty cycles may need a high-performance gear oil with EP additives. Lubrication rates vary according to the screw diameter, number of rollers and the amount of heat to be dissipated.

Providing sufficient protection against contaminants is also critical to long functional life. For instance, if metal chips get into the nut assembly, the roller screws may grind them into a lapping compound, which will cause spalling and eventual catastrophic failure. Shaft wipers, bellows, shrouding and enclosures protect roller screw components from environmental contaminants, and should be selected according to specific application requirements. For example, wipers can be added to the front or back of the nut to scrape particulates from the threads throughout the screw stroke. Additionally, force tubes that house roller screws keep lubricants in, while preventing contaminant infestation. Force tubes with IP67 ratings are available in a wide array of mounting options.

Improper loading is another possible cause of roller screw failure. As a general rule, lead screws do not tolerate applied moments or side loading, so high-precision slide rails should be used to carry these loads and make certain that loading on the nut is co-axial to the lead screw.

Although roller screws may have a higher initial cost than alter-native motion actuation systems, they usually provide significant cost savings in the long run. In fact, a properly specified and maintained roller screw system typically costs half that of the cumulative cost of ball screw systems, since they do not need to be replaced or maintained as frequently.

www.exlar.com

The new sizes 300 and 500 meet the highest requirements concerning torque, compactness and dynamics. Features include high rigidity, extreme precision and excellent performance, making the TPM+ 300/500 actuators a fundamental contribution to increase the productivity of any machine.

Technical specifications at a glance:

- Torque up to 10,000 Nm

- Compact design coupling the alpha TP+ 300/500 gearbox and 220 series motors

- Optional strengthened output bearing (special gear housing)

www.wittenstein-us.com