Air motors up to 4.4 kW by Mannesmann Demag with integrated brake

Pneumatic Motors up to 4.4 kW with Holding Brake from Mannesmann Demag – Technology, Application, Selection

This category system includes pneumatic motors up to 4.4 kW with holding brake from Mannesmann Demag. The units are designed as steel housing variants and cover nominal powers from 2.2 kW to 4.4 kW. Typical applications are found in production and handling technology, drives for clamping devices, conveyor positioning, and in applications where electrical solutions are to be replaced by pneumatic drives: zones with explosion hazards, heavy contamination, or high shock loads. The following text provides technical details on construction, materials, connections, seals, and braking technology, as well as practical selection and installation instructions.

Construction and Materials

The motors are housed in robust steel casings. Shafts, bearing supports, and sealing sleeves are designed for continuous industrial use. Shaft materials typically consist of hardened steel (e.g., 42CrMo4 or comparable) to absorb both torque transmission and axial and radial loads. Bearings are low-maintenance roller or tapered roller bearings, depending on the model, to accommodate high radial and axial forces. The internal impeller and rotor profile are precisely manufactured to maintain constant efficiency and idle speed. Sealing systems combine oil seals with secondary U-rings or multi-acting shaft seals to minimize compressed air losses and prevent lubricant migration.

Braking Technology: Function and Design

The integrated holding brake is designed as a spring-applied/magnetic clutch brake that closes upon loss of compressed air (safety-oriented rest position). Brake linings use heat- and wear-resistant friction materials; braking surfaces are ground or honed to ensure constant braking torques. Brake units are usually modularly assembled, allowing for replacement and inspection without disassembling the motor. Control air connections for the brake are routed separately and must be secured by check valves and filter pressure regulators to exclude foreign air, moisture, and particles.

Connections, Air Preparation, and Control

Compressed air connections are standardly available as G or NPT threads; flange connections can be supplied if required. To ensure service life and performance, filter-regulator-lubricator (FRL) units are necessary: filtration 5 µm or finer, pressure regulation according to the motor's nominal pressure (often 6–8 bar), finely dosed oil mist lubrication depending on manufacturer specifications. On the control side, directional control valves with low unflowed leakage volume should be used. For the brake, magnetically controlled valves with redundant power supply or pneumatically redundant circuits are recommended to increase functional safety.

Idle Speeds, Torque, and Characteristic Curves

The series offer different idle speeds, resulting from internal over- or under-geared rotor geometries and flow cross-sections. Typical idle speeds range from a few hundred to several thousand min−1; torque increases proportionally with pressure and volumetric flow. For precise design, the characteristic curves of torque versus speed at a defined supply pressure are crucial. Pay attention to reduction factors when mounting with gearboxes and thermal load capacity during continuous operation.

Seals, Lubrication, and Maintenance

The sealing systems are designed for different media: dry compressed air applications use abrasion-resistant elastomers (NBR, FKM) and hard material coatings; moist or oil-laden air requires specialized materials and maintenance intervals. Lubrication is performed using permissible oil additives (observe ISO viscosity specifications); avoid over-oiling, as this can contaminate friction pad linings. Maintenance intervals depend on operating conditions; typical inspection points are: brake lining wear, air filter element, pressure regulating valve, shaft seal, and bearing clearance. Documented inspection intervals increase operational safety and reduce unplanned failures.

Installation and Mounting Instructions

During installation, alignment and concentricity of the motor shaft and coupled components are critical: eccentricity or angular errors increase bearing load and seal wear. Pay attention to the tightening torques of flange and mounting screws according to manufacturer specifications. Choose an installation location that allows maintenance access to the brake and ensures ventilation openings are not blocked. Route brake lines short and with minimal bends, and secure them with condensate drains and check valves. For temperature-sensitive applications, use suitable sealing kits (e.g., FKM for high temperatures).

Practical Application Examples

Example 1: Clamping device on a hydraulic press. A 3.3 kW pneumatic motor with integrated holding brake replaces an electric motor in an explosion-hazardous zone. The motor is coupled via a direct flange gearbox; the brake securely holds the press mold during the manufacturing cycle. An FRL unit (5 µm filter, 6 bar, oil mist lubrication according to manufacturer) and a solenoid valve-controlled braking system with reset upon pressure drop are installed. Maintenance interval: check brake linings every 1500 operating hours.

Example 2: Positioning drive in a conveyor belt. A 2.2 kW pneumatic motor drives an indexing station via a planetary gearbox. The holding brake ensures exact positioning during tool changes. For fine adjustment of the torque, a pressure reducer is installed before the motor; the line to the brake is equipped with a fine screen (1 µm) and condensate drain to eliminate particles and water. Result: reduced downtime and constant positioning accuracy over several shifts.

Example 3: Safety shutdown in pipeline shut-off valves. A 4.4 kW motor with holding brake is used as an emergency shutdown gearbox. In case of pressure loss, the spring brake mechanism locks the valve in its current position; redundant pneumatic supply ensures safe restart. Additional sensors document the brake status, and monitoring data are integrated into the control system.

Selection Criteria and Checklist

• Power (kW), required starting and holding torque, desired idle speed, available compressed air installation, environmental influences (temperature, humidity, explosion class), connection type and flange dimensions, braking behavior (fail-safe/energize-to-release), maintenance access, and spare parts availability.

Safety and Compliance Aspects

For use in Ex-zones, ATEX/IECEx conformities must be checked. Review documentation for permissible ambient temperatures, protection classes (IP ratings), and recommended sound insulation measures. Brake functions must be assessed for safety; redundant controls or monitoring loops may be necessary to comply with machinery directives.

Further Information and Application Examples

Technical details on pneumatic technology, air preparation, and practical applications can be found on our technology page: https://maku-industrie.de/technik. Further specific application cases and project references are available at https://maku-industrie.de/anwendungsbeispiele.

FAQ

1. How do I choose the right motor power and braking force?
First, determine the required starting and holding torque based on load moments, friction, and safety factors. Select motor power such that at nominal air pressure, the required torque is achieved at the desired idle speed. For the brake, choose a holding capacity with an additional safety factor of at least 1.5 compared to the maximum restraining torque.

2. What air preparation is required?
At least a 5 µm filter, pressure regulator corresponding to the motor's nominal operating pressure (often 6–8 bar), and metered oil mist lubrication according to manufacturer specifications. In humid environments, additionally a condensate drain and a fine filter (1 µm) for brake system lines. Use adsorption or refrigeration dryers if processes are particularly critical for dry air.

3. What maintenance intervals apply to the brake and bearings?
Visual and functional tests of the brake are recommended every 500–1,000 operating hours, comprehensive inspections including brake lining and bearing condition every 1,500–3,000 hours depending on the application profile. Document all maintenance and follow manufacturer specifications for wear parts and lubrication specifications.