Discover the Electromagnetic brake, their functionality and areas of application. As precise Spring pressure brake or efficient Permanent magnet brake They are essential for control and safety in automated and manual drive systems. Learn how these innovative braking systems improve performance and ensure reliable operation.

Contents

• Electromagnetic brakes – the most important things in brief
  • Spring-applied brakes stimulate the energy transition
  • Spring-applied brakes for robot arms
  • Electromagnetic brakes for vertical axes
  • Electromagnetic linear brake with 10 times faster switching time
  • Select the correct servo safety brake
  • Spring pressure and permanent magnet brake in comparison
  • Electromagnetic brake rod and rod clamping
• Applications of electromagnetic brakes
• FAQ

Electromagnetic brakes – the most important things in brief

The Development of electromagnetic brakes is advancing as they are valued for their efficiency and precision in various industrial sectors. Demand is increasing, especially with regard to Safety brakes, due to their ability to stop machines instantly, increasing workplace safety. This is particularly valued in the material processing, vehicle construction and printing industries.

The trend goes to greater efficiency and reliability and the brakes become smarter. Equipped with Brake Monitoring They can be used for predictive maintenance or condition monitoring. In the wake of the energy transition, greater emphasis is being placed on sustainability, which is already common practice in the automotive industry Braking energy recuperation is also used in industrial drives. 

Spring-applied brakes stimulate the energy transition

November 07.12.2023, XNUMX | Spring-applied brakes have been providing power for more than five decades Kendrion INTORQ Electric motors in Industrial trucks of all kinds with a safe braking function. In the wake of the energy transition and the associated electrification of the transport sector, the Aerzen brake specialists have significantly expanded their area of ​​application and are now increasingly making their expertise available to the area of ​​e-mobility.

Vehicle manufacturers not only benefit from tried-and-tested quality and customer-optimized brake design, but also from the energy-efficient technology from Kendrion INTORQ, which is manufactured in a sustainable production process.

“The electrification of vehicles and materials handling vehicles is currently taking place at great speed,” describes Marco Vollrath, Sales Manager at Kendrion Intorq shares his observations. “Among other things, we see this trend in agriculture, the construction sector and of course in the automotive industry. Added to this is the growing market for driverless transport systems (AGV/AGV). This makes our many years of brake expertise in the area of ​​electric motors all the more important. We know what these brakes have to do and can provide our customers with the specialized advice and supplies they need in the various areas.”

Areas of application for the spring-applied brake – yesterday and today

Kendrion INTORQ developed its first spring-applied brake in 1971 for a forklift model. Today the company dominates the industrial trucks market segment worldwide. As a result of the need to drive emission-free in halls and closed areas, there is in many cases no alternative to electrical operation of industrial trucks. Accordingly, two out of three of these vehicles now have an electric drive. At the same time, the motor, brake and battery technology used has been repeatedly adapted and optimized over the decades - a technological advantage that automobile and commercial vehicle manufacturers can currently benefit from when electrifying their drive technology.

The spring-applied brakes from Kendrion INTORQ have also been continually perfected over the years in terms of functionality and energy efficiency. After opening, the brake can be kept open with a very low energy requirement through an optimally coordinated holding current reduction. “In addition, we always advise our customers so that the individual brake solution is only as large as necessary and as small as possible,” explains Marco Vollrath. “In this way we will reduce energy consumption to the necessary minimum.”

Produced with renewable energy

The topics of energy efficiency and sustainability not only play a role in the operation of Kendrion INTORQ brakes, but are also taken into account during their production. The company covers part of its electricity needs via a PV system and heats its production halls using local heat from a neighboring biogas plant. “Our brakes have also been used in wind turbines for many years,” summarizes Marco Vollrath. “This closes the cycle – because that’s where the energy is produced that drives the electric motors, which in turn are stopped by our spring-applied brakes.”

Spring-applied brakes for robot arms

Oct 05.10.2023, XNUMX | With the new standard modular system for robot brakes, Mayr is creating the basis for solutions at an attractive price level. On the PLC 2023 In Nuremberg the company is showing how intelligent, talking brakes and... Shaft coupling can be cleverly used for process monitoring and so on Powertrain Get ready for Industry 4.0 at low cost.

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Electromagnetic brakes for vertical axes

16.08.2023 | Mayr presents to EMO 2023 its portfolio of electromagnetic, pneumatic and hydraulic Safety brakes for securing vertical axes in machine tools and machining centers. These vertical axis brakes protect against all dangerous situations that can occur when operating axes subject to gravity.

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Electromagnetic linear brake with 10 times faster switching time

23.11.2021 | To secure linear movements at standstill e.g. B. due to a power failure, safety brakes are often used. They act on separate round rods or piston rods or guide rails. Depending on the applications come here often pneumatic or hydraulic Opening brakes are used because they offer high holding forces.

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Select the correct servo safety brake

June 03.06.2020, XNUMX | The safety brake for holding a certain position and for emergency stop situations is an important component in the servo drive. So far this applies Servo brake in some cases not monitorable. Mayr With the Roba-servostop, has developed a servo safety brake in a modular system that is particularly suitable for... Robotic offers a solution.

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Spring pressure and permanent magnet brake in comparison

June 03.06.2014, XNUMX | Both spring-applied and permanent magnet brakes have their place. But which one is the right one for the respective application? Since very different aspects have to be taken into account when making the selection, the user should rely on competent advice. Then it is of course an advantage if the brake manufacturer providing advice has both operating principles in its program and advises without any self-interest. The article from the manufacturer of clutches and brakes Kendrion shows that not all brakes are the same.

Depending on the operating conditions, a distinction is made between holding and working brakes. The Holding brake has the task of keeping loads at a standstill. The braking of the movement is carried out by the drive. Only in the event of an error, e.g. B. during an emergency stop, the holding brake performs braking work to bring the system to a standstill and then keep it at rest.

In contrast, the Working brake the task of destroying the kinetic energy and then keeping the system at rest when it is at a standstill. Typical areas of application for holding and working brakes can be found in elevators, overhead conveyors and wind turbines as well as in robotics and mechanical engineering.

The use of work brakes is becoming more and more in the background as modern ones Drives and Controllers cope with the braking task safely and also wear-free can work. Applications in which work brakes are used are served by spring-applied brakes because the organic friction systems used there - similar to the brake pads in cars - are well suited to providing a high level of overall work over the service life.

Both permanent magnet and spring-applied brakes are used for the vast majority of holding brake applications. The user is spoiled for choice here, as in so many other areas. He has to decide which one Operating Principle is best suited for its application. Both have characteristic properties that make them ideal for different areas of application.

Two principles of action - different properties

Both types of brakes are closed when de-energized. It is a matter of Safety brakes: In the event of a power failure or failure of the energy supply, such as a line break, the system is kept safe. However, there are fundamental differences beyond that. With the spring-applied brake, which is usually installed on the B bearing side of an electric motor, springs press against the armature disk of the brake when de-energized.

The Friction linings of the rotor, which is connected to the motor shaft via a toothing, is clamped between this armature disk and the mounting surface of the brake on the rear of the motor. When the brake coil is energized, a magnetic field is created that attracts the armature disk and thus releases the rotor with the friction linings. The brake releases.

When it comes to the active principle permanent magnet On the other hand, in the de-energized state, the armature or rotor is pulled against the stator or the excitation system by the permanent magnetic field. When energized, an electromagnetic field is created that cancels out the attractive force of the permanent magnets and thus releases the armature from the excitation system through the tensile force of the springs between the armature and the flange hub. The brake releases.

The force-fitting connection The permanent magnet brake is free of play between the armature, hub and shaft. However, defined installation conditions must be adhered to in order to ensure a defined air gap in the engine.

Permanent Magnet Brakes

From these two active principles with their different Friction pairings, steel/steel in the permanent magnet brake and organic friction linings/steel in the spring-applied brake result in defined, essential properties that result in typical fields of application for both types of brakes:

Permanent magnet brakes (PE) are well suited for servomotors, for example in handling technology and Robotic. Here they are particularly impressive due to their compact dimensions and their comparatively low weight. Thanks to the permanent magnets, the power density is twice as high as usual with spring-applied brakes (FD). But there are also other reasons why people tend to prefer lightweight, dynamic and almost abrasion-free brakes in robotics.

The freedom from abrasion of the PE brake is ensured by this mode of action the brake is ensured. The anchor is completely released by the spring. With the FD brake, start-up wear occurs because when the speed increases, an air cushion must first build up between the pad and the friction surfaces. This wear can occur due to acceleration of the friction disk, e.g. B. the acceleration due to gravity when the drive is arranged vertically or due to centrifugal forces when the rotor blades of a wind turbine rotate. Usually only one friction lining is affected.

When used, the PE brake behaves as a pure holding brake Emergency stop function different from the FD brake. Due to its design, the PE brake is free of residual torque. There is only abrasion during the emergency stops. When actuated, the armature is completely released by the spring. In contrast, the FD brake has a starting torque, which leads to a certain amount of wear with every start. The above-mentioned wear and tear caused by acceleration forces makes things even more difficult. Often this additional wear cannot be determined precisely because usually only one side of the friction disk is affected.

Whisper-quiet elevator brake secures elevators and escalators

Another difference lies in the behavior Temperature range. PE brakes are very temperature stable and have a guaranteed high torque over the entire temperature range. Things are different with FD brakes. Here, the temperature stability is essentially influenced by the composition of the organic friction lining. You can compare this to a car tire, which is also developed for different operating conditions. Just as a Formula 1 tire cannot be used in winter, some organic friction linings cannot be used in brakes.

With a high coefficient of friction, the covering has good adhesion high torques, but the covering wears out very quickly. For pads in FD brakes this means: pads with high coefficients of friction show a greater drop over the entire temperature range and sometimes only have half the torque at 120° or -40°C. In general, it can be said that FD brakes either achieve very good torque, but are not as temperature-stable or that the coefficient of friction is comparatively lower with a temperature-stable pad. However, it should be emphasized that within a given temperature range, the torque of the FD brake can be adjusted very precisely to the torque specified by the customer in the design process.

Allrounder spring pressure brake

Lifting and travel drives with high braking energies and defined braking torque, i.e. controlled deceleration during an emergency stop, cannot be operated by PE. In addition, there are numerous applications where high dynamics and power density are not required. Cranes, overhead conveyors and roller doors provide typical examples of this.

The brake must brake if the worst comes to the worst Emergency stop If necessary, deliver high deceleration values ​​per braking and reliably maintain the weight. The switching time and power density only play a minor role. High braking work is no problem for the organic friction linings of the spring-applied brakes and they can also be used as a working brake if necessary.

Besides, that is moment of inertia Due to the comparatively low weight of the friction disc, it is lower than with permanent magnet brakes. In addition, these applications usually use IEC standard motors on which spring-applied brakes can be easily and quickly installed. The brake, whose structure is less complex than permanent magnet brakes, usually remains easily accessible.

Anyone who has a cost-effective solution in an application Standard standard motor can therefore normally use a spring-applied brake. For the respective area of ​​application, e.g. B. for a specific operating temperature range, a friction lining optimized for the application can be selected.

The FD brake With the correct selection of the organic friction lining and the design of the springs, it can be easily adjusted to a desired torque with a relatively small tolerance. If the temperature range is still comparatively small, the torque can be maintained well within this range. In addition, development has not stopped when it comes to spring-applied brakes: With the new Kobra brakes from Kendrion, 80% more torque or three times the service life can be achieved compared to previously available solutions on the market. By reducing the control power, power consumption is reduced by a third. Less heat is generated, which reduces component aging.

Electromagnetic brake rod and rod clamping

November 28.11.2011, XNUMX | With the HMSB has HEMA developed a rod brake that works with a spring energy storage based on the proven spring principle and can therefore be used not only as a service and holding brake, but also as an emergency stop brake. Due to the electromagnetic operation, the compact HMSB does not require a hydraulic or pneumatic connection for its small installation space.

There just one power connection with 400 V AC nominal power and the electronic control is already integrated, the HMSB can be easily installed or retrofitted.

If there is no tension on the brake, the spring force presses a conical bushing axially into a conical bore in the housing. This narrows the cross section on the inner diameter of the bushing, so that it clamps onto the central round rod with high force (8 to 14 kN). The spring force is reinforced via the cone angle of the socket. To open the brake, the HMSB is supplied with current, whereby an integrated strong electromagnet attracts a flat armature, which presses the clamping bush out of the cone seat against the spring force. After the tightening phase, the power consumption of the brake is less than 15 VA. At 199 x 120 x 152 mm, the brake has a very compact design and can also be used in harsh environments thanks to its IP65 protection rating.

In the version as a brake, it is clamped on the rod Cone bushing not firmly connected to the housing. Therefore, the mass attached to the housing increases the braking force because it leads to further wedging of the bushing (holding force 14 kN). This ability to move the socket relative to the housing prevents precise positioning, but this is not necessary when braking.

However, for applications that require a precise positioning without braking effect, there is a version available as a rod clamp (holding force 8 kN). With this, the cone bushing is firmly connected to the housing and therefore cannot be easily moved as with the brake version - ideal for precise positioning. During clamping, the spring presses on a freely movable hub with an inner cone, on which the magnetic force also acts to open it.

Applications of electromagnetic brakes

There are safety brakes from Mayr hardly any industrythat the drive specialist does not serve. They protect people and machines in elevators and escalators, in stage technology, the railway industry, test stand technology and the steel industry, in wind turbines, crane systems and winch technology, extruders, wastewater technology, in tunnels and mining and much more.

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FAQ

What is an electromagnetic brake?

An electromagnetic brake uses a magnetic field to slow or stop mechanical motion, typically the rotation of a shaft. It is electrically activated to energize an electromagnet, which in turn applies a braking force to a metallic surface, slowing or stopping movement without direct contact. Known for their precise control and instant response, these brakes are often used in applications where fast and reliable braking action is required.

How does a magnetic brake work?

A magnetic brake uses the power of magnetism to slow or stop movement. When electric current flows through a coil, a magnetic field is created. This field acts on a metallic brake disc or brake drum. Eddy currents create a counterforce that inhibits movement. An electromagnetic brake uses the magnetic field to actuate mechanical brake pads that press against a rotating disc or drum, stopping movement. This type of brake allows very precise control of the braking force and is therefore used in many areas of application.

What is a spring brake?

A spring-applied brake is a mechanical brake in which the braking force is generated by preloaded springs. These brakes are designed to exert a braking effect in their idle state when no current is flowing. Braking is achieved by releasing the spring force that presses on the braking elements and stops the movement. They are often used as safety brakes to safely stop a machine in the event of a power failure or emergency stop.

What is a permanent magnet brake?

A permanent magnet brake is uses permanent magnets to create braking force. Unlike electromagnetic brakes, which generate a magnetic field using electrical current, permanent magnet brakes use the constant magnetic field of permanent magnets. These brakes create a braking effect through the magnetic attraction that acts on a metal disc or other part. Known for their reliability, lack of maintenance and consistent braking power, they are often used in applications where continuous or long-term braking action is required.

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