Brakes + Clutches - Motion Control Tips

Zero backlash featured in Miki Pulley CSZ electromagnetic clutches

January 10, 2019 By Miles Budimir Leave a Comment

Miki Pulley’s CSZ electromagnetic clutches have a zero backlash design and provide an efficient connection between a motor and a load with low inertia, minimal drag and zero backlash.

CSZ clutches function using the magnetic force generated by the energized coil providing engagement of input and output members of the clutch. They feature an integrated bearing design making mounting fast and easy while ensuring application concentricity and excellent system runout. CSZ clutches operate well in temperatures from +14 to +104 °F (-10 to +40 °C).

Available in bores ranging from 10 to 15 mm, with brake torques ranging from 1.77 to 7.376 ft lb (2.4 to 10 Nm), the CSZ uses corrosion-resistant materials, and is RoHS compliant like all other Miki products.

“Miki Pulley’s CSZ clutches are a great choice for high performance printing, paper processing, packaging, food processing and textile manufacturing systems,” reports Jon Davidson, Miki Pulley sales specialist. “They are proven performers in system applications around the world.”

For more information about Miki Pulley CSZ clutches, visit www.mikipulley-us.com.

Video on torque limiters: Examples of how to customize for industrial applications

December 6, 2018 By Lisa Eitel Leave a Comment

In a recent video with Lee Teschler, we go over three torque limiters from Mach III — a Kentucky-based manufacturer of stock and custom brakes, clutches, and torque limiters. The manufacturer can usually deliver custom designs within two days of obtaining application requirements. Mach III also meets or beats purchase-order ship dates 98% of the time. Catalog products ship in 2 to 5 weeks and custom in 3 to 6.

Recall that friction torque limiters transmit a set torque from the motor end of an axis to the driven-load end — and protect both from overload. Should torque exceed a set value, the torque limiter slips.

So let’s check out our first sample — a T2A2R-STL mechanical torque limiter … on which a sprocket, pulley, or sheave can mount. This is a spring-engaged design having low-coefficient friction discs. Minimum torque is 20 lb-in. and maximum torque (with 27% spring compression) is 200 lb-in. This one-pound torque limiter works on axes with speeds to 1,750 rpm.

Of course, torque limiters can integrate into motion systems in a few ways. We just considered one that accepts input via a sprocket-and-chain or pulley-and-belt assembly. Now let’s consider one for shaft-to-shaft mounting.

The V2R2R-STL is a mechanical torque limiter with adapter sleeve. The latter necessitates simple but precision installation with a torque wrench and other tools … But these torque limiters usually ship with the specified torque value to within about 10%.

Our third and final sample here is a V2G2R-STL shaft-to-shaft mechanical torque limiter. It’s complete with rigid coupling. This is a spring-engaged unit capable of torque maximums of 20 to 200 lb-in. depending on the setting.

One caveat: All these torque limiters are for momentary events and will continue slipping until the jam or other overload source is cleared. That means designs employing these components must include some way to detect torque overloads.

For more information, visit machiii.com and motioncontroltips.com.

Video: Spring or air-engaged friction brakes from Mach III (a Design World overview)

December 5, 2018 By Lisa Eitel Leave a Comment

In a recent video with Lee Teschler, we got the chance to handle two brakes from Mach III. Watch the video:

Our first sample — a D2F3R-STH spring-engaged brake — is one of more than a dozen standard variations … with many more customizable options.

This modular brake design has subcomponents grouped into kits — for drive-hub elements, drive-disc elements, piston elements, cylinder elements, and a final kit that includes two O-rings, 24 coil springs, and three friction discs. It’s recommended that end users keep these common wear items on hand for very critical applications where downtime must be minimized.

Torque is to 91 lb-in. and maximum speed is to 1,750 rpm. As with most all brakes, the manufacturer recommends a service factor of 1.5 to 2 when calculating required torque. Brakes shouldn’t be used at maximum rated torque for continuous duty.

So that was a spring-engaged brake … the other sample we show in the video is an air-engaged brake — the Mach III B2F2R-STH. Dynamic torque for this flange-mounted brake at 80 psi input is 100 lb-in.

Of course, torque capacity is only one factor to consider when selecting a brake. Mach III recommends that design engineers contact the engineering department for application review and assistance.

The pneumatic supply must include a flexible airline and correct fitting for the brake inlet’s NPT size — and fixing with a thread-sealing compound. Air supply should be both filtered and regulated. For more information, visit machiii.com.

Click to enlarge.

Video: Five air-engaged clutches from Mach III (a Design World overview)

December 4, 2018 By Lisa Eitel Leave a Comment

In a recent video with Lee Teschler, we investigated five air-engaged clutches from Mach III. The company designs and manufactures an array of air and spring-applied friction brakes and clutches — as well as mechanical torque limiters and combination clutch-brakes for industrial applications to 5,000 ft-lb. Watch the video:

First we detail a C2H2R-STH air-engaged shaft-to-shaft flexible-coupling clutch. These friction clutches (as with all the other samples we detail in this video) engage with air pressure and then are spring released upon air exhaustion.

In this way, they connect and disconnect fully supported shaft pairs. An elastomeric element compensates for up to 3° of angular misalignment and up to 0.040 in. of parallel offset between shafts.

In contrast, a sprocket or pulley mounts on the pilot of the C2A2R-STH air-engaged clutch. This is a through-shaft-bored variation in a miniature-clutch line for torque requirements of less than 200 lb-in.

The C2D2R-STH air-engaged clutch we examine in the video is designed for end-of-shaft mounting … and for cycling and connect-disconnect applications.

It fixes to the shaft with setscrews or a customer-supplied key and includes a rotary air seal. Unlike the other clutches we consider in this video, this one does not need an anti-rotation arm to prevent rotation of the air housing.

Next check out this M2G2R-STH air-engaged shaft-to-shaft rigid clutch coupling. It has a two-piece coupling body — with both the clutch mechanism and coupling half bored to accommodate differing shaft sizes.

Last but not least, we have an M2R2R-STH air-engaged clutch mechanism with adapter. Torque capacity is to 190 lb-in. As with the other clutches here, torque is linear in response to input air pressure. It’s also available with friction linings having a low or high coefficient for the same price. Linings with a low coefficient of friction are for designs needing a bit of slip or a narrow torque range.

These are just a tiny sample of what the manufacturer offers — in more than 2,000 standard models — though most of what Mach III supplies are slightly custom to very custom designs. In that regard, the manufacturer is somewhat ahead of a growing trend we see in industry. For more information, visit machiii.com.

Click to enlarge.

Model-112 Micro Brakes from Miki Pulley excel in small precision equipment

December 1, 2018 By Lisa Eitel Leave a Comment

Electromagnetic Micro Brakes from Miki Pulley are a compact, high performance braking solution for small, precise motion control applications.

Model 112 Micro Brakes from Miki Pulley ouput fast braking response when the rotating portion of the brake (armature) engages the stator when the coil is energized. A constant-force plate spring transfers torque to the rotating brake body halting all motion. These brakes are suitable for precise motion applications.

Miki Pulley’s ultra-compact brake design ensures fast response in high torque demanding applications. The simple yet effective design features a stator with integrated mounting flange, proprietary composite friction liner and armature complete with ring plate spring and hub.

These field-proven Miki Pulley Micro Brakes halt rotation mechanically by using electromagnetic field to create mechanical friction. With fast response, the brake’s armature engages the stator when the coil is energized. A constant-force plate spring transfers torque to the rotating brake body halting all motion.

Additional features include quiet operation, high holding torque for its size, space saving design configuration, long service life, stable and reliable braking power. Easily installed, these Miki Pulley Micro Brakes need no maintenance and come in three armature-assembly options to satisfy myriad application requirements.

112 Model Micro Brake specification range based on model selected:

Brake torque: 0.295 ft-lb to 1.770 ft-lb (0.4 Nm to 2.4 Nm)

Backlash: Zero

Ambient temperature: 14° F to about 104° F (-10° to about 40° C)

For more information, email jdavidson@mikipulley-us.com or visit mikipulley.co.jp.

Ogura explains how permanent-magnet brake work with new animation

October 8, 2018 By Lisa Eitel Leave a Comment

Ogura Industrial Corp. has created a new animation showing how permanent magnet brakes work. The animation shows an exploded view of the component parts and how they interact with each other.

In permanent magnet brakes, holding force is created by permanent magnets and released by energizing the magnetic field.

Permanent magnet brakes are higher torque and smaller diameter versus spring applied brakes. Permanent magnet brakes also allow torque to be controlled by varying the offsetting current to the brake. Brakes are used on a wide variety of medical, robotic and other motion control applications.

Check out the video on the manufacturer’s website and on YouTube:

Ogura Industrial Corp. has been producing clutches and brakes since 1938. Over that time, the brakes manufacturer has developed more than 5,000 different models of clutches and brakes. Although Ogura primarily produces electromagnetic clutches and brakes, the brakes manufacturer also produces magnet particle brakes and clutches as well as mechanical, pneumatic, and hydraulic motion components —and a variety of specialty products. Ogura is the world’s largest manufacturer of electromagnetic clutches and brakes … current manufacturing capacity is more than 30 million units per year.

To provide localized support, the brakes and clutches manufacturer has manufacturing plants spread throughout the world — in Asia, The Americas, and Europe. All manufacturing facilities are ISO certified and conform to ISO 9001;2008, ISO 140001, and ISO/TS 16949.

Design engineers seeking a special product or modification to existing standard models should call (732) 271-7361 or visit www.ogura-clutch.com.

For a given motion profile, when are other options for stopping insufficient — and a clutch or brake necessary?

August 19, 2018 By Lisa Eitel Leave a Comment

At the core of most motion axes are electric motors. Stopping loads on their axes can be done with the electric motor itself — called internal braking in certain contexts — or with an external clutch or brake. For the former, one simple approach is to simply cut motor voltage input and allow the axis to coast to stop. That’s acceptable where stops are infrequent — from a few times a minute (for designs running off small motors) to a few times an hour (for larger motor installations). Another option is to use controls to generate stopping torque in the motor via regenerative braking t convert kinetic into electrical energy; dynamic braking — the injection of dc current into the stator; or electric reversal as plugging.

But where such approaches are too slow — including all modern motion designs for high throughput — external brakes and clutches are required to get sufficiently quick stops or disengagement. This applies to conveyors, airport-baggage handlers, escalators, and elevators … as well as other axes that make frequent stops and starts — even as few as 10 cycles a minute in some cases. Where stops and starts happen at much higher cycle rates, motor inertia may degrade the quickness with which starts and stops are possible. So here, clutch-brakes are often more suitable — as they disengage the driven load from the motor to allow the former to run even while the brake engages and stops the load. Of course, though we focus on responsiveness here, failsafe design features are another main driver of brake and clutch inclusion.

Mechanical, electric, fluidic, and self-actuated clutches and brakes are suitable for different applications. For example, spring-set brakes benefit motion designs that slow loads with the motor before the brake engages … and they’re suitable as holding mechanisms. Control of electric brakes is easy, and they can keep pace to a thousand cycles per minute. Most air-actuated brakes and clutches are cool-running and hold with minimal input. Friction brakes with drum, disc, and cone geometries deliver e-brake functionality with failsafe holding.

Brake or clutch size and type depend on whether the axis at hand will make emergency stops or softer stops that sacrifice the clutch or brake to protect systems and loads from shock. Or sometimes it’s more essential that the brake deliver soft stops to prevent shifting loads and misalignment. After that, other criteria — cycle rates, thermal capacity, machine envelope, and MRO schedules — dictate final selection.

Miki Pulley’s BXR-LE electric spring-applied brakes are suitable for small and precise servomotor designs. A lightweight design optimizes servodrive performance and efficiency. Its voltage controller means the brake’s power consumption is stepped down to 7 Vdc after a split second of 24 Vdc for actuation. When compared to most other electric brakes, the BXR-LE brake consumes just a third the power (and generates just a third the heat) — though it’s half as thick. Speed is to 6,000 rpm; static friction torque is 0.044 ft.lb. to 2.36 ft.lb. and ambient operating temperature is 14° to 104°F. BXR-LE brake applications include those on end effectors, ballscrew actuators, XYZ positioning tables, and 3D printers.

Some tips: Size clutches and brakes to the machine axis’ motor torque. Where a brake must stop vertical loads, account for how motors can briefly draw current to output in excess of their rated torque. Consult performance curves in manufacturer PDFs for dynamic torque ratings at set speeds to match the brake or clutch to peak motor-output torque. Case in point: Consider an inclined conveyor with regularly spaced on-off cycles. Here, a power-off spring-set brake may suffice to prevent load crashes during power failures. But more complex conveyor installations to position discrete product of varied size — without jerking — may need multiple deceleration rates may need more sophisticated spring-set brake plus drive on the motor for stopping … or even a permanent-magnet brake for quick yet soft starts and stops.

Comparing clutch and torque-limiter functions

Torque limiters are not clutches, as they’re not designed to continuously slip. That’s an important distinction when design engineers are specifying slowing and disengaging technologies for mechanical designs. Some tips for optimal design selection: First consider whether a torque limiter will only protect against catastrophic failure or semi-regular overloads. That will indicate whether an economical friction-style torque limiter is sufficient or if the design necessitates a ball-detent design. The latter is usually more costly but capable of slipping and triggering a limit switch for shutoff and resetting to resume operation. Ball-detent torque limiters here can slip multiple times in their application … unlike friction torque limiters requiring reset.

When applying a torque limiter, confirm whether a zero-backlash design is needed. Note that torque limiters can generate heat at their frictional connections, so upon their activation, system shutdown is key. After it’s activated, the end user should inspect the torque limiter for wear and heat damage. He or she should also check its setting torque … as in some designs, that value will be diminished if the torque limiter has been run too long. As long as the torque limiter is still within design range, it’s safe from exhibiting more and more slipping. With some motion designs, a limit or proximity switch paired with controls can detect when the torque limiter slips — and shuts the system down to let the end user address the issue the torque limiter was protect (or protect against). || Insight into torque-limiter functions provided by KTR engineering services manager Chris Scholz.

Brake modules such as the mayr ROBA brake-checker and the ROBA torqcontrol monitor the condition of safety brakes — and can facilitate smooth deceleration of machines and devices. Shown here is a ROBA brake-checker module that without sensors. Electronics track current and voltage and recognize the movement of the armature disc to assess brake condition as well as temperature, wear, and tension path or tensile force reserve — in other words, whether the electromagnetic brake’s magnet has sufficient force to attract the armature disc. On reaching the tensile force reserve, a warning signal sounds to prompt service. There is a design for ac voltage; a coming version of the module will integrate brake input power supply (and replace a separate rectifier) for switching condition monitoring and brake control in one device.

Miki Pulley BXR-LE electric brakes for direct drive servo motors

August 10, 2018 By Mike Santora Leave a Comment

Miki Pulley’s BXR-LE electric spring applied brakes are suitable for small and precise servo motor configurations. Their unique compact and lightweight design optimizes servo drive performance and efficiency.

With accompanying voltage controller, the brake’s power consumption is stepped down to 7VDC after a split second of 24VDC for brake actuation. When compared to most other electric brakes, the BXR-LE design provides just one-third power consumption and heat generation in one-half the overall size thickness.

Specifications:

Maximum RPM: 6000
Static friction torque range: 0.044 to 2.36 ft.lb. (0.06 to 3.20 Nm)
Ambient operating temperature 14° – 104°F(-10° to 40°C)

Additional applications:

End effectors.
Ball screw actuators.
XYZ positioning tables.
3D printers

Miki Pulley
www.mikipulley.co

Safety brakes and intelligent monitoring from mayr for brake technology 4.0

June 28, 2018 By Lisa Eitel Leave a Comment

Safety brakes by mayr power transmission are equipped for the challenges of the Industry 4.0. The coordinated system guarantees the highest level of operational and functional safety …

… and increases the productivity of machines and systems through predictive error detection and maintenance.

Brake technology 4.0 stands for intelligent monitoring modules; modules such as the ROBA-brake-checker and the ROBA -torqcontrol monitor safety brakes easily and quickly or facilitate the even and smooth deceleration of machines and devices.

mayr power transmission as the leading manufacturer is already offering reliable safety brakes, which are equipped for the challenges of the forth industrial revolution.

Permanent brake monitoring and predictive maintenance

The ROBA -brake-checker module operates without sensors. Instead, it analyzes current and voltage and recognizes the movement of the armature disk. So it knows the condition of the brake. In addition to the switching condition, the module can also deduce the temperature, wear and tension path or tensile force reserve — in other words, whether the magnet still has sufficient force to attract the armature disk.

On reaching the tensile force reserve, the ROBA-brake-checker emits a warning signal, early enough so that a defined operating time of the brake is still possible. Within this time, the machine operator can undertake specific maintenance in coordination with their work process – maintenance with foresight, so to speak. The ROBA -brake-checker is now available in a design for AC voltage. In addition, another version of the module will also in future take on the supply of the brake, and as a result, replace the rectifier. Switching condition monitoring and brake control are therefore combined in one device.

Braking movements gently and in a controlled manner

For applications, which need braking torque control in addition to status monitoring, mayr power transmissions provides the braking torque control module ROBA -torqcontrol. It shares the features of the ROBA -brake-checker and can also change the level of the braking torque in operation through purposeful influencing of current and voltage. As a result, devices and machines can be evenly and gently decelerated. The ROBA -torqcontrol module permits the development of control loops and brakes movements intelligently – the suitable basis for its use in smart, interconnected machines.

The brake control module ROBA -SBCplus performs reliable switching time monitoring. It is type-certified by TÜV Süd and can be used up to the highest Performance Level PLe and Safety Integrity Level (SIL) 3. Image: mayr power transmission

Another module to continuously monitor the switching condition of the brakes is the safe brake control ROBA -SBCplus. In this module, mayr power transmission offers safety brakes and safe brake control in a complete package. This module has been developed in collaboration with the company Pilz, especially for applications which have to fulfil requirements for the protection of people according to standards regarding functional safety. The ROBA -SBCplus module must reliably interrupt the current in the magnetic coil when the brake is switched off. For this purpose, the module operates with wear-free electronic semi-conductors, and as a result achieves practically unlimited switching frequency and switching reliability.

Brake technology 4.0 by mayr power transmission stands for monitoring modules of the latest generation: The modules such as the ROBA-brake-checker or the ROBA-torqcontrol allow permanent brake monitoring and make the safety brakes fit for the challenges of the Industry 4.0.

This brake control module performs reliable switching time monitoring. Furthermore, an integrated plausibility check is conducted through the evaluation of the release monitoring signals. The evaluations of the switching states and the return signal therefore permit reliable error diagnostics. This permits creep errors which influence on the switching times, for example increasing wear, to be detected in due time. The reliable ROBA -SBCplus brake control unit is type-certified by TÜV Süd (Technical Inspectorate, Southern Germany) and can be used up to the highest Performance Level PLe and Safety Integrity Level (SIL) 3.

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.