Tolomatic caliper disc brakes include (clockwise from top-center): pneumatic; spring-applied (fail-safe) with hydraulic or pneumatic release; hydraulic for high torque; hydraulic and mechanical combination; and mechanical brakes.
Contamination prevention in harsh environments, burgeoning brake and clutch technologies and the future of regenerative braking.
Friction materials in brakes have become more environmentally friendly in recent years and now produce greater friction coefficients with less wear.
According to Keith Hogan, product manager with MN-based Tolomatic, rubber boots and seals have been a few brake additions to improver product reliability in harsh environments. The boots and seals help keep contamination from interfering with moving components.
“There has been a growing market for stainless steel brake components for use in wash-down industrial applications such as dairy processing, food packaging and pharmaceutical manufacturing,” Hogan says.
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Materials used in clutches and brakes have advanced as a result of demanding applications found particularly in the aerospace and defense market segments.
“There have been innovative solutions for sealing and covering moving parts,” says John Pieri, IL-based Thomson Industries’ product line manager. “When there is a need for operation in harsh environments, special coatings for corrosion resistance have been developed. With the use of magnetic finite element analysis, special alloys with built-in corrosion resistance are also being used.”
While brakes are considered a fairly mature product category — the overall design and functionality hasn’t changed much in the past five years — there has been increased brake demand.
“There has been an increase in the demand for brakes, mainly power-off spring set brakes,” says Pieri, who suggests that clutch usage has flattened out. “In some cases, the use of clutches and clutch couplings is now threatened by the use of low cost motor and drive technologies.”
Pieri suspects that clutch and clutch coupling usage will decline as spring set power-off brakes become more widely used.
Hogan focuses on price point and performance when looking into the future of brakes. “Without a doubt, there will be continuing pressure to reduce the cost of braking components while maintaining or even improving performance and durability,” he says.
Electric Actuation
While brake selection depends entirely on the application, Pieri believes that electromagnetic friction and wrap spring clutches and brakes are two of the most popular products on the market.
“There is a current trend to provide electric actuation over fluids and pneumatics,” he reports. “As electric motors have become smaller, more energy efficient, powerful and lightweight, the demand [has risen] for electromagnetic clutches and brakes.”
Growing markets like medical, aerospace, defense and robotics have driven the demand for electric actuation. The electric vehicle market in particular (hybrid automotive, electric lifts and other off highway vehicles) has continued to grow.
Drum Style
“The most common brakes on the market today are disc-and-caliper brakes due to their simplicity, ease of pad replacement and overall performance characteristics,” says Hogan.
While Hogan recognizes that drum-style brakes have waned in popularity, he believes that they will still be used in some situations.
“Drum-style brakes are lower cost with a larger friction area and greater stopping torque for a given diameter,” Hogan says. “However, drum-style brakes are more difficult to adjust and service than disc brakes … and they have a tendency to corrode in harsh environments if not used regularly.”
Disc Clutches
The longstanding clutch design used in low horsepower industrial applications, the disc/cone clutch, was perfected more than 40 years ago, but continues to be popular in many industrial applications.
“In this unique design, the cone engages a cup on the pilot plated for immediate, positive engagement with no slippage,” says Hogan.
According to Hogan, the pneumatically-operated disc/cone clutch offers high torque and a compact profile in a lower duty cycle applications.
Regenerative Braking
Regenerative Braking utilizes AC motor and drive technology to generate electricity like a generator. The energy source comes from back-driving the motors, such as slowing down a vehicle while it’s going down a hill.
According to Pieri, brakes and clutches are gaining momentum in this emerging market.
“Regenerative braking increases the use time of a vehicle’s battery and is an alternate solution for dynamic stopping,” says Pieri. “Clutches and brakes are partnered with this technology — spring set brakes are used in tandem as the parking or emergency brake.”