Construction Machinery .

Pan and planetary batch mixers with a 0.5–4.5 m³ output need gearboxes with high reduction ratios (i = 25–63) and high radial load on the output shaft from the weight of the mix and abrasive aggregates. Boneng P-series in-line planetary units or heavy-duty K-series bevel-helical gearboxes with double shaft seals against cement dust are a good fit.

• Ratio 25–63
• Service factor ≥ 1.5 for 30–60 starts per hour
• Double lip seals with dust shield
• Optional backstop for emergency unloading
• IP65 protection against pressure washing of the housing

The main hook hoist combines a high-voltage motor or VFD-fed motor, a dedicated crane gearbox with two output shafts, and two brakes (service plus emergency). Boneng HB-series 2- and 3-stage helical gearboxes with a service factor ≥ 1.8 and a built-in mounting flange for the brake disc are typical.

• Ratio 16–63
• Output torque 8–80 kN·m
• Service factor ≥ 1.8
• Mounting flange for brake disc Ø 315–710 mm
• Bearings rated for radial load from the rope drum

Tower-crane jib slewing and trolley travel are driven by planetary gear motors with a high reduction ratio (i = 80–250) and an integrated multi-disc brake. The slewing mechanism runs in a reversing duty of 100–200 starts per hour and requires accurate positioning via a VFD. Boneng P (Brevini-style) or Guomao P series fit this duty.

• Ratio 80–250
• Integrated multi-disc parking brake
• VFD-compatible with position feedback
• Provision for an encoder on the input shaft
• IP65, outdoor execution

SC-series construction elevators run on a mast up to 250 m high at a cage speed of 0–60 m/min. One drive consists of a 5.5–15 kW motor, a worm-helical or helical gearbox (i = 16–32) and a drive pinion engaging the rack on the mast. Two or three parallel drives per cage are typical for redundancy and load sharing.

• Ratio 16–32
• Output torque 0.8–4.5 kN·m
• Stiff output shaft with splines for the pinion
• Compatible with the cage centrifugal safety gear
• Protection against ingress of construction dust

General-purpose bevel-helical (K) and parallel-shaft (F) gear motors for aggregate belt conveyors and cement feed screws. Inclined conveyors require a backstop on the input shaft to prevent reverse rotation of a loaded belt at shutdown.

• K-series (45° bevel) or F-series (parallel-shaft)
• Service factor at least 1.4
• Optional backstop on the input shaft extension
• Reinforced seals against cement and bitumen dust
• Tropical execution option for mobile batch plants

Crane-duty squirrel-cage induction motors of the Wolong YZP/MQ series or similar dedicated lines with a starting torque of 2.0–2.5 times nominal. They operate at S3 40 % with 150 starts per hour. The motor has a tapered shaft extension for a brake disc or a built-in electromagnetic brake. Windings are class H with PTC thermistors in each phase.

• Rating 22–65 kW, S3 25–40 % duty
• Starting torque ≥ 2.0 times nominal
• Insulation class H, PTC thermistors
• VFD-compatible (NEMA MG1 Part 31)
• IP55, outdoor execution

Low-voltage induction motors of 5.5–15 kW with a built-in electromagnetic brake. Two or three motors per hoist cage run in sync from a single VFD. The brake is spring-applied and released by 220 V DC — on power loss the cage is automatically held on the mast.

• Rating 5.5–15 kW, 380 V
• Built-in DC electromagnetic brake, engagement ≤ 0.15 s
• Threaded IP65 cable gland, watertight
• Insulation class F, thermal contacts
• Optional forced ventilation for VFD operation

General-purpose induction motors Wolong YE3/YE4, rated 30–300 kW. Asphalt plants need a tropical execution with improved winding protection against bitumen vapours and bearing temperature monitoring. Concrete plants need a dust-tight execution with extra labyrinth shaft seals.

• IE3 (30–150 kW), IE2 (above 150 kW)
• IP55 minimum
• Tropical execution for asphalt mixers
• Compatible with a soft starter
• Optional Pt100 RTDs in windings and bearings

HPUs of drilling and pile-driving rigs, pile drivers and vibratory drivers carry 90–450 kW induction motors running in continuous S1 duty at a steady 70–90 % of nominal load. The motor sits on a common base with the pump and is coupled through a flexible coupling or a flange. A marine execution is often required for offshore drilling.

• Rating 90–450 kW, continuous S1 duty
• Rigid keyed shaft for a flexible coupling
• IP55 minimum, optional marine execution
• Insulation class F, temperature rise to class B
• ISO 10816 vibration monitoring on heavy-duty units

Electrohydraulic disc brakes of the Huawu YPZ2/YWZ5 series are mounted on the motor shaft extension or on an intermediate gearbox shaft. A dual-brake layout is used: the primary (service) brake stops the drive in normal operation, while the spring-applied emergency brake closes on power loss or overspeed. Engagement time is 0.1–0.2 s.

• Braking torque margin 1.75 for service, 2.0 for emergency
• Engagement time on power loss ≤ 0.2 s
• IP55, operating range −40 to +60 °C
• Dual brake set on one shaft
• Pad-wear limit switch

Each hoist drive carries a spring-applied electromagnetic brake built into the motor. The cage is additionally fitted with a centrifugal safety gear — a mechanical device that trips at a descent overspeed of 30 % above nominal and locks the cage on the mast rack. Huawu DZS/DZE motor brakes run at S5 duty with 200 engagements per hour.

• Braking torque 1.5 times nominal motor torque
• Motor-integrated execution (flange mount)
• 220/110 V DC supply from a rectifier
• Service life of at least 5 million cycles
• Compatible with the cage centrifugal safety gear

When out of service, a tower crane must be either clamped to the rails or set to weathervane mode with the slewing brake released. Storm-brake rail clamps of the Jingu CWZ / Zhonghai SB series engage automatically when wind speed exceeds the 18–20 m/s set point (anemometer signal) and hold the crane in winds up to 35 m/s. They are backed by a UPS in case of external power loss.

• Holding capacity in winds up to 35 m/s
• Automatic engagement on anemometer signal
• UPS backup of at least 2 hours
• Pneumatic or hydraulic release
• IP65, all-weather execution

Inclined belt conveyors feeding aggregate to batch concrete plants and asphalt mixers carry Tianiu NJ/NF backstops on the gearbox input shaft extension. When the drive stops they lock reverse rotation of the loaded belt. A band or shoe emergency brake is added for scheduled maintenance.

• Backstop on the gearbox input shaft extension
• Holding torque margin of 1.5 over rated
• Shoe or band emergency brake
• Manual release capability
• Protection against cement dust and bitumen vapours

The tower-crane slewing mechanism and the jib trolley use multi-disc parking brakes integrated into the gearbox. The brake is spring-applied (normally closed) and released by hydraulics or compressed air simultaneously with the motor start command. It holds the jib against wind-load torque and load inertia.

• Multi-disc design in the gearbox oil bath
• Spring-applied, hydraulically released
• Braking torque 1.5 times rated operating torque
• Service life of at least 1 million cycles
• In-situ wear diagnostics without disassembly

Jiaohua YOXp and Yongjing TLL series are pin couplings with an integrated brake drum of Ø 200–710 mm. They sit between motor and gearbox on conveyors and screw conveyors, with the drum doubling as the seating surface for a shoe brake. They damp starting shocks and accommodate small radial misalignments of 0.2–0.8 mm.

• Torque 0.5–25 kN·m
• Brake drum Ø 200–710 mm
• Radial misalignment up to 0.8 mm
• Elastic pins of NBR or polyurethane
• Pin service life of at least 25,000 h

Yongjing GIICL and Longxuan WGZ gear drum couplings transmit torque from the gearbox to the crane rope drum. The crowned tooth profile accommodates angular misalignments up to 1.5° caused by elastic frame deflection under load. On tower cranes they are used on the main hoist drives with torques up to 80 kN·m.

• Torque 5–80 kN·m
• Angular misalignment up to 1.5°
• Grease lubrication, 6-month interval
• G6.3 balancing at peripheral speeds above 10 m/s
• Protective shrouds against dust

Tianiu NJ/NF/MZ are backstop couplings with a roller or sprag gripping mechanism. They sit on the conveyor gearbox input shaft extension and lock reverse rotation when the drive stops. This is critical for crushed-stone and cement conveyors inclined more than 8°: at shutdown the loaded belt tends to run back and, without a backstop, accelerates to dangerous speeds.

• Holding torque 0.5–50 kN·m
• Overrunning speed up to 1500 rpm
• Operation at sub-zero temperatures
• Protection of bearings against cement dust
• Service life of at least 100,000 trip cycles

Longxuan ZL and Yongjing LM are combined couplings with a brake drum for rope winches of pile-driving rigs and mobile-crane outriggers. The drum doubles as a winch barrel or as a seating surface for a shoe brake. They accommodate radial misalignments up to 1 mm once the frame has warmed up under load.

• Torque 1–50 kN·m
• Drum Ø 250–800 mm
• Provision for a shoe or band brake
• G6.3 balancing at speeds above 8 m/s
• Replacement of elastic elements without removing the coupling