Brakes + Clutches - Motion Control Tips

Miniature brakes, clutches, and torque limiters from Mach III for shaft sizes to a half-inch

April 24, 2018 by Lisa Eitel Leave a Comment

Brakes, clutches and torque limiters are now available from Mach III for shaft sizes of half-inch and smaller. The ten new products include:

• A spring-engaged brake for power off applications

• An air-engaged brake for stopping and holding applications

• Five air-engaged clutch configurations for connect and disconnect applications

• Three mechanical torque limiters for overload protection applications.

These products are currently used in MRI scanners, a variety of food packaging and labeling systems, remotely operated inspection cameras, quality control equipment, and machinery that produces faux eyelashes.

Development of these smaller sized products was driven by client demand.

“Over the past couple of years, we have experienced a high volume of inquiries from machine designers looking for products for half inch and smaller shafts,” said said Mach III application and design director Ron Ashbrook. “In some cases, these were new machine designs. In others, the engineers were seeking replacements for products that performed poorly, became too costly, or had inordinately long lead times.”

After developing a number of custom designs for these clients, it made sense to expand the Mach III catalog line to encompass these smaller sizes.

The outside diameters of the miniature units are between 2.58 and 3.28 in., and the lengths of most are less than 3 in. Torque capacities are to 200 lb-in. at 80 psi. All are available bored and keyed to spec for imperial and metric shafting and have an average two-week lead time. All can be customized with enclosures and special finishes to suit application requirements. Get full specifications and 3D models at the machiii.com page detailing the miniature clutches and torque limiters.

Mach III is an application-focused designer and manufacturer of air and spring engaged friction brakes, clutches, combination clutch-brakes, and mechanical torque limiters. Mach III products are used in machinery to connect and disconnect, stop, hold, control tension, and protect machine components from overload. Torque requirements up to 60,000 lb-in. can be accommodated. Engineering, sales, production, customer service, and product support are all located under one roof in Walton, Ky.

How do cam clutches work, and what are other overrunning clutch options?

April 17, 2018 by Lisa Eitel Leave a Comment

Mechanical overrunning clutches, sometimes called one-way or backstop clutches depending on the context, transmit torque in one drive direction but let the output axis continue to turn (freewheel) when the driving motor slows or stops. Such clutch function is useful in large and small designs for material handling, packaging, conveying, medical, turbine auxiliary drives, and off-highway applications.

Common mechanical overrunning clutches include those that use ratcheting, roller ramps, wrap-spring, and cam action for one-way axis engagement.

Ratchet clutches are basic two-element overrunning clutches that use a tooth that interlocks with a frame in one direction and freewheels in the other. Roller-ramp clutches have cylinders that lock into steps on a wheel or (upon reversal) roll freely. Wrap-spring clutches have helical springs that tighten down onto on a cylindrical sleeve to transmit torque in one direction.

Of these designs, cam clutches (sometimes called sprag clutches, especially in transportation industries) are relatively new and power dense. An array of bars profiled with asymmetrical cam-shaped geometry ring the circumference of the clutch. Cages at each end keep the bar cams evenly spaced. Upon input rotation, the cams act as rising wedges to lock between the races on the inner and outer clutch halves.

More specifically, cams in some cam-clutch variations fill the space between the races to quickly act as a sprags and hold the clutch halves together via locking friction. Upon reversal, the cams quickly release (and then tolerate high overrunning speeds). In other cam-clutch designs, centrifugal force makes the bar cams turn into liftoff to disengage the clutch halves. Then upon slowing or reversal, a spring at each cam pushes them back into sprag-type engagement.

Cam clutches are especially rugged. Top: BS-HS Series clutches from U.S. Tsubaki Power Transmission are high torque and rated for high maximum overrunning speed. The red-highlighted areas are where the cams backstop when the inner race turns clockwise. Bottom: BR-HT Series cam clutches use a slightly different mode of engagement based on centrifugal force. When the inner race turns clockwise with sufficient speed, the cams pivot so their geometry clears both races. Otherwise, springs cause the cams to pivot back to a default and lock the clutch halves together.

No matter the variation, the geometry of cam clutches’ load-bearing cams tightly pack into the clutch body. That means it’s often two other factors that limit torque capacity:

Bore size (and connecting shaft size with it)
The effects of tangential forces where the cams meet the races.

But some cam clutches exhibit comparably less ID and OD race deflection and contact stress than other designs thanks to distributed loading during engagement. That in turn extends life and makes for smoother engagement. Some cam clutches even use ground alloy-steel races to maximize uniformity of load distribution. Because jamming under load can occur where wear is excessive, some cam clutches for demanding applications feature precision-formed cams to resist wear and prevent failure from fatigue.

As mentioned, other overrunning clutches include those that use ratcheting, roller ramp, and wrap-spring action.

Ratcheting clutches are basic two-element clutches that use a single-tooth arm that engages a toothed wheel in one direction and freewheels in the other. These are most common in powered consumer products and light industrial tools.

Roller-ramp clutches engage through ground steel rollers that run and lock on a wheel precision machined with incline ramps. Note that some roller-ramp clutch literature describes roller engagement with a cam. This isn’t to be confused with the cam arrays of cam clutches, as here the cam is singular and refers to the assembly’s wheel that’s machined with ramps.

Hilliard Corp. overrunning clutches are for high-torque applications needing positive engagement. The roller-ramp design transmits power from the input (motorized) shaft’s precision roller-and-wheel assembly. Ball bearings support this assembly’s roller cage and align it to the output shaft. Because the clutch has large areas for variable roller contact, it prevents localized wear to extend reliability and service life. Torque is from 275 to 925 lb-ft (373 to 1,253 Nm) with speeds to 16,000 rpm.

Operation relies on concentricity between inner and outer races, so most roller-ramp clutch iterations include compression springs to maintain roller-to-wheel contact. The springs install at angles engineered to optimize initial actuation and holding grip. Because of the way the cylindrical rollers lock into flat steps on the inner wheel, these clutches transmit high torque and withstand high overrunning speeds. In addition, roller-ramp clutches are low cost and easy to repair even while offering high overrunning speed and torques.

Wrap-spring clutches have springs that coil around a cylindrical output to tighten down when turned in the drive direction. This creates friction to lock the assembly and transmit torque. Wrap-spring clutches excel in applications of moderate speed — commonly to 2,000 rpm or so.

Clutch/brakes allow precise positioning with virtually no maintenance or adjustment

April 5, 2018 by Miles Budimir Leave a Comment

Posidyne clutch brakes from Force Control Industries feature oil shear technology for rapid and precise stopping, starting, speed change and positioning, all without adjustment or maintenance. Ideal for applications with frequent start/stop cycles, such as indexing conveyors, rotary tables, batch feeders, rotary coal samplers, cutoff machines, and more, these unique motion control devices allow higher cycle rates (up to 300 cycles/min), to increase production rates with lower downtime. Faster production rates and significantly longer service life than traditional (dry) clutch/brakes (often 5 to 10 times longer) yields increased uptime, productivity and ROI. Posidyne clutch/brakes are field proven in diverse applications such as lumber mills, shingle plants, fiberglass insulation production, food processing, packaging, metalworking, and many more.

Low-inertia cycling components makes the Posidyne clutch brake more efficient, requiring less motor horsepower to accelerate the load, and less torque to stop the load. Their totally enclosed design is impervious to dust, chips, chemicals, coolants, caustic wash down, weather, and more, making them ideal for hostile environments.

Posidyne clutch/brakes feature a multiple disc design that produces high torque from a small package. Re-circulating the fluid dissipates the heat of engagement, which is a common cause of downtime with other clutch/brake assemblies.

A simple actuation system allows torque in the clutch and brake to be precisely controlled. Adjustment for rapid or soft starts and stops is easily accomplished. Manifold mounted control valves reduce response times by eliminating hoses and fittings, and are recommended for high cycle applications. By reducing the high starting inrush currents and the associated power factor imbalance in the motor, these unique clutch/brakes can also reduce energy costs.

The Posidyne clutch brake can be actuated by air or hydraulic pressure for use in a plant or outside remote applications. The hydraulic actuation package includes a hydraulic pump, solenoid valve, regulators, and a filter. A heat exchanger can be added for additional cooling.

The Posidyne is inherently explosion proof with the addition of an explosion proof actuation valve, or locating the valve in an explosion proof cabinet. Multiple sizes are available to suit particular applications from ½ to 350 hp (99 lb-in. to 79,000 lb-in.) with cooling options, control logic and mounting arrangements to simplify and speed installation.

For more information, visit www.forcecontrol.com.

New ultra-thin power-off brake from SEPAC

March 8, 2018 by Miles Budimir Leave a Comment

SEPAC’s new line of extremely thin power-off brakes, the UTSEB Series (Ultra Thin Spring-Engaged Brakes), is offered in five standard frame sizes from 1.14 to 2.68 in. in diameter and lengths from 0.47 to 0.67 in. The ultra-thin design provides a short package size when the brake is mounted to the rear of a motor; and when mounted to the front, there is room for mounting a pulley. What makes the UTSEB’s small size exceptional is the increased torque-to- diameter ratio performance — offering static torques of over 22 lb-in. The low-inertia UTSEB also has minimal backlash, less than 1.5°.

Used for power-off engagement applications, the UTSEB is equipped with a PWM controller to reduce heat and save energy, making it a cost-effective solution for continuous duty applications in robotics and automation systems. Energizing the brake’s UL Class F insulated coil with 24 Vdc, the PWM controller then provides 7 Vdc to hold the brake in the power-on/brake-released position. This dramatically reduces ongoing heat generation by conserving current and wattage draw. When power is turned off, the coil’s electromagnetic field dissipates, allowing the springs to push the armature plate into contact with the long life friction disc material. This squeezes the friction disc between the pressure plate and the armature plate, thus transmitting torque to stop/hold the friction disc, hub, and shaft.

The UTSEB is RoHS compliant and is available with wide ranging customized interface dimensions. As a standard service, SEPAC provides comprehensive in-house design resources to modify the UTSEB configuration to accommodate most customized application requirements.

For more information visit www.sepac.com.

New zero-backlash, spring-engaged brake family

March 6, 2018 by Paul Heney Leave a Comment

Nexen Group Inc. has announced the Zero-Backlash Spring Engaged (ZSE) brake family. The pneumatically-released ZSE offers high torque, high speed, and zero backlash ideal for holding applications. Unlike brakes using leaf springs to transmit torque, the ZSE is zero-backlash up to 100% of its rated holding torque.

Nexen has released four different sizes (450, 600, 800, 1000) for a wide variety of applications. The bore sizes are available in three standard sizes, and can be easily customized for customer needs.

In addition, Nexen offers an option to configure the ZSE with a smart feature. The ZSES brakes are available with internal sensors, making them ideal for Industry 4.0 compatibility. These sensors provide feedback and data to maximize machine safety and efficiency.

Highlights of the ZSE Brake include:

Speeds up to 5000 rpm
Zero-Backlash up to 100% of rated holding torque
Holding torque up to 300 Nm
Zero-Backlash integral clamp collar
Low inertia
Customizable to wide range of shaft diameters
Cool operation
Compact housing
Optional Smart feature for Industry 4.0 Compatibility

Brakes and clutches: Top trends in IoT — and uses on ac-motor conveyors and servodesigns

March 4, 2018 by Lisa Eitel Leave a Comment

Clutches and brakes work in motion systems to stop or hold or index axes — but must do so to application specifications. No wonder then that the trend in this technology is away strictly stock parts. According to Lesli Riehemann, president at Mach III Clutch Inc., customized brakes and clutches are now 75 to 80% of her company’s annual production. What’s more, an increasing number of clutch and brake manufacturers are now looking to supply non-catalog products — and so customization has become normalized.

Matrix spring-applied, electromagnetically-released 1EB Series servo motor brakes are widely used on industrial robot applications. The brakes maintain torque during static/holding operations and occasional E-stop (dynamic stopping) engagement in the case of power failure.

In fact, industrial brakes and clutches could become a $1.7 billion market by 2024, mostly due to investment in industrial automation and the rise of smart factories. That’s according to Global Industry Analysts Inc. (GIA). The quickest-growing industries include those related to material handling, food and beverage, machine tools, and textiles. As with other technologies, the fastest rate of adoption is in the Asia-Pacific region — with a CAGR of 8.4% for the clutch and brake market over the next six years.

Some designs have backup drives that engage if there’s an emergency and the main drive becomes inoperable. Traditional designs require something to manually or electrically decouple the main drive and connect the backup — for example, on military vehicles or platforms to let operators use manual auxiliary mechanisms when needed. Because brakes usually hold drive position, they must be manually disengaged for the manual system to begin driving. Now, Mechanical Torque Lock (MTL) products from Carlyle Johnson are a new option that automatically transfer motion to secondary drive systems. They include a spring-engaged electromagnetically released clutch for automatic braking when the motor drive is de-energized or if vehicle power is lost.

Whether stock or specific to an application, clutch and brake specification and integration must be simple. For more on this — and what else design engineers require from designs today, we spoke with Gary Haasch, senior product and engineering manager at the Electric Clutches and Brakes Group of Altra Industrial Motion. Here’s what he had to say.

Automated guided vehicles (AGVs) and other battery-powered mobile equipment are increasingly common. Here, we sell an ERS Brake specifically designs for AGV systems to provide static holding with limited emergency-stop dynamic braking. As with AGVs, the trend for all-terrain vehicles (ATVs) and utility task vehicles (UTVs) today is for the brake or clutch manufacturer to provide features that necessitate less effort for the end user — including more mechanical control with less physical effort. On a related note — that of automated warehousing — we’re selling more C-Face-mounted clutch brakes than in the past. These are for controlling ac-motor-powered conveyors.

In contrast, Cartesian robots require servomotor brakes — with the ability to engage in static holding … and with functional e-stop dynamic braking of servomotors for each axis of a robot.

• On the topic of IoT — the fact is that the IoT is here … it’s no longer the future. So the sky’s the limit on what remote actuation (and dashboard monitoring) can work on the many devices in our everyday lives. We see IoT influencing the brake and clutch industry so we’re starting to investigate where IoT might be helpful as a value-added feature. Direct consumer products have the most appeal, but the market isn’t financially ready to support IoT functionality. That said, as the cost for technologies to support IoT functionality comes down, we think we’ll see more controllability and feedback through smartphone technology.

For now, our focus is to educate end users on the value of real-time access to system information — including functional alerts (to prompt adjustments) or predictive maintenance of clutches and brakes.

On the topic of industrial IoT (IIoT), increasingly networked manufacturing has spurred us to begin several programs for operators wanting remote access and monitoring. For example, one potential IIoT clutch application is for the activation (and performance and condition monitoring) of a clutch assembly in an oil-well pump jack.

Right now a manufacturer uses our clutch in this application to let an engine restart without load after maintenance. Our clutch also disengages the engine if the oil level of a well falls below a suction tube (to let the oil level recover). More specifically, this is a Warner Electric Mag Stop clutch (which is bearing mounted and has steel friction plates); a pulley accommodates twin V-belts that drive the pump shaft. The modified clutch is a variation of standard CMS clutches (which come rated to 200 or 250 ft-lb). Before the clutch was added to this design, the engine kept running (which accelerated wear) or shut down (necessitating restart).

Besides IoT, we see other trends in the design and use of brake and clutch technology …

• In applications where safety and e-stopping is networked, power-off brakes are increasingly common, as these brakes engage immediately when the power source is disabled.

• On the topic of software to improve designs — we use electromechanical simulation software on clutch and brake designs to get maximum torque performance. The software simulates lines of flux from a wound coil to predict the attractive force that yields the torque capacity of the clutch or brake. This in turn lets us validate designs much faster than what’s possible with traditional design approaches — which are usually through a build-test-redesign product development cycle.

• In terms of new brake offerings over the last year, we’ve introduced more power-off brakes for both static holding and dynamic e-stop braking of servomotor-driven applications … and similar brakes for electric vehicles.

Warner Electric ERS Series brakes are spring-set and electrically released to provide holding as well as occasional dynamic stopping functions in emergency situations.

Ogura MS series clutches, brakes now available in North America

February 8, 2018 by Miles Budimir Leave a Comment

Ogura Industrial announces the availability of its MS series of clutches, brakes and combination clutch-brake units to North America. The MS series is finding new opportunities for machinery manufacturers in North America due to its unique features.

The MS series is a complete line of clutches, brakes and combination clutch brake units available in eight sizes ranging in torque from 9 to 738 lb-ft. The key advantage with the MS series is that it can automatically adjust for wear. Once a clutch or brake is set in an application, the armature maintains the proper airgap so that time to speed or time to stop remains constant through the life of the unit. In addition to individual clutches and brakes, there is also a foot-mounted version that is enclosed in a foot-mounted housing with both double-bearing input and output shafts providing excellent overhung load capability

For more information, visit www.ogura-clutch.com.

SEPAC intros spring-engaged, power-off brake for aerospace applications

January 16, 2018 by Miles Budimir Leave a Comment

SEPAC has released a 1-inch electromagnetic spring engaged, power off (SEB) brake for aerospace and defense applications. This unique brake, 1inch in diameter, is suitable for small actuators and ideal for the limited space and difficult performance requirements of missiles and unmanned aerial vehicles (UAVs). SEPAC’s SEB can withstand extreme temperatures as well as high levels of vibration and shock.

SEPAC’s in-house design resources have extensive aerospace/defense and aviation expertise, allowing them to quickly customize the company’s high-performance, off-the-shelf brakes for military applications. This capability offers customers a significant time-to-market advantage in terms of prototypes and finished product.

Highlights of the SEPAC SEB include:

1-in. diameter
Available in 28 V for usage in standard aircraft or customizable voltage for other applications
Can be used for dynamic stop or holding-only applications
Aerospace and other custom coatings

For more information, visit www.sepac.com.

SEPAC announces line of thrust reverser brakes for aviation use

December 22, 2017 by Paul Heney Leave a Comment

SEPAC Inc. has announced a line of high-performance thrust reverser brakes, which are used to prevent the thrust reversers on an airplane from being engaged in flight. SEPAC’s thrust reverser brakes are suitable for any aerospace application, and are currently used on platforms such as the Airbus A380 wide-body jet and the Irkut MC-21 Russian airliner.

Highlights of SEPAC’s thrust reverser brakes include:

RPM up to 20,000+
Dual coils for superior reliability
28V for usage in standard aircraft or customizable voltage for other applications
Multiple discs for high torque in a small package
Aerospace-rated coatings and corrosion protection

SEPAC has in-house design resources with aviation, aerospace and defense expertise, allowing them to quickly customize the company’s high-performance, off-the-shelf brakes for other applications. This capability offers customers a significant time-to-market advantage in terms of prototypes and finished product.

SEPAC Inc.
www.sepac.com

Expanded size selection for BX Series brakes from Miki Pulley

December 8, 2017 by Miles Budimir Leave a Comment

Electromagnetic BX series brakes from Miki Pulley are a power-off, engaged type brake. Of the BX series, the BXR-LE has expanded to three additional sizes, with six total size configurations to choose from. These brakes boast advantages including a slim design and high holding torque in a compact package. They provide quiet operation with long service life. This brake was designed for smaller machine and robotic applications, where cantilevered loads can negatively impact operation. The brake’s unique compact and lightweight design optimizes machine design efficiency. With accompanying voltage controller, power consumption is stepped down to 7 VDC after a split second of 24 VDC for brake actuation.

When the stator is energized, the brake is disengaged allowing free rotation. When no current is applied, compression springs halt the brake rotor thereby stopping the input shaft rotation. This is an ideal feature to prevent power failure events.

When compared to the other BX brakes in the Miki lineup, the BXR-LE design provides just one-third power consumption and heat generation in one-half the overall size thickness. Specifications are:

Maximum rpm: 6,000
Static friction torque range: 0.06 Nm – 3.20 Nm (0.044 ft-lb – 2.36 ft-lb)
Ambient operating temperature: -20 ˚C to 60 ˚C (-4 ˚F to 140 ˚F)

Applications for the BXR-LE brakes include: