Brakes for electric linear actuators
Due to their precise and smooth operation as well as their high power density, it is obvious why electric linear actuators and servo motors have paved the way for superior control in many industries that require critical linear positioning.
KEB has acknowledged this trend and has had great success with the implementation of permanent magnet and spring-applied brakes within our customer’s actuators and servo motors.
The linear actuator applications vary widely but can include military, food and packaging, and medical machinery. In such industries, there is significant demand for accuracy and repeatability. Missing a precise position or failing to hold a load in place without slippage could yield catastrophic results. Additionally, these machines are often holding heavy and expensive equipment so incorporating a brake is often necessary for added security.
Brake Selection for Linear Actuators
KEB typically supplies 2 different brake products for electric actuator applications. They are Permanent magnet brakes and spring-applied brakes. Both are power-off brakes but each brake has its own advantages.
Permanent magnet brakes (see how PM Brakes work) offer better torque density. They have roughly 33% more torque in a given diameter, compared to spring-set brakes. So if a small brake diameter is required this style is preferred.
As technology advances and machines become intricate, space is often constrained, as a result, permanent magnet brakes have become a more attractive option to many customers. Permanent brakes also offer zero-backlash performance and are well suited for high-precision applications.
Although the P1 permanent magnet brakes are power-off, they are not spring-applied nor are they considered fail-safe. For critical applications like lifting or hoisting, KEB spring-set brakes are preferred (see how spring set brakes work). KEB’s spring-set brakes provide reliable brake engagement in the case of loss of power or even excessive friction lining wear.
Standard features for spring-applied and permanent magnet brakes include:
- Insulation class: Rated for ISO class F. Class H is possible if needed.
- Protection: Rated at IP 20 protection however most customers typically locate brakes within the actuator housing yielding protection ratings up to IP 69.
- Coil voltage: Most commonly 24VDC but all common voltages are available (12, 24, 48, 105, 205).
- Certifications: CSA and UL listings are possible for both designs.
- Hand Release*: Optional manual hand release (spring-applied only). Note the hand release option does limit the IP rating as the brake release handle needs to travel outside the housing.
- Dust boot: Optional dust boot for IP44 protection with exposed brake, this can be used with hand release (spring-applied only)
- Dimensions: Most metric/imperial bore sizes possible with keyways.
Beyond our standard product features, we can also offer custom features to accommodate the linear actuator design. The advantage KEB offers is that we will dive into your application as well as your specific actuator design and assembly to ensure we have an optimized solution. The primary location to mount a brake is usually within the actuator or servo housing on the back shaft of the motor.
This can be a hassle as there is often limited space and minimal flexibility on the brake profile that will fit within this section of the housing. By investing the time to understand our customer’s products we find small tweaks that we can do to our standard products to allow optimal fitment to accommodate the available real estate. Similarly, we can pinpoint custom features to implement that will ease or enhance assembly on the customer’s end.
Some custom features we have accomplished in the past include:
- Customer specified cable connectors.
- Specified torque window
- Custom mounting or flange to accommodate actuator housing.
- Custom package to accommodate actuator housing.
- Encoder mounting holes on brake magnet.
- Extended hub collar to provide sandwich stack-up assembly within actuator housing.
- Cutouts along the side of the brake profile to allow wire passage.
Why Choose KEB?
Experience matters. KEB has been manufacturing brakes since 1972. Through the years, we have partnered with many of the leading linear actuator companies to develop reliable high-performance actuator brake solutions.
One reason KEB has earned our reputation in this corner of the industry is the flexible offering of solutions we have. Beyond our standard product line, we are willing to provide custom solutions to accommodate customer needs. This could be something as simple as special connectors or an adapter plate. Or it could be something with added complexity like a custom magnet with boosted magnetism. We can even design drop-in replacements for older or hard-to-source designs.
We have full design and manufacturing capabilities at our US location in Shakopee, Minnesota. We take on custom solutions and ensure that we supply the right products for the specific application.
Local engineering and production do not mean expensive – we work with our customers to offer economical solutions which meet the application requirements.
Obviously, a locally manufactured product helps us to be responsive. KEB America has successfully replaced a number of different European, Indian, and Chinese brake competitors. Long lead times with shipments are not acceptable in today’s demanding marketplace.
KEB – The Brake Partner for your Actuator
We’d love an opportunity to work on your next design project – Contact a KEB America engineer today!
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