SY1250C2C3KH Rotary Device Sany SY1350C1C3KH Tracked hydraulic excavator spare parts

SY1250C2C3KH Rotary Device Sany SY1350C1C3KH Tracked hydraulic excavator spare parts

The SY1250C2C3KH slewing unit is a core slewing assembly customized by SANY for its 125-ton class large hydraulic excavators. It integrates a high-load-bearing slewing bearing, dual-drive slewing motors/reducers, an electro-hydraulic slewing system, and a dedicated sealing and lubrication module. It is a key component for achieving relative rotation between the upper and lower hulls and for bearing the machine’s overturning moment and lateral loads. Primarily used for continuous slewing operations in mining stripping, massive earthmoving, and large-scale infrastructure projects, it achieves low vibration, high response, and long-life slewing through deep matching of structure and control, preventing downtime caused by slewing jams, impact overloads, or leaks. Adaptable to extreme working conditions of high temperature, high dust, and high impact, it is a core component for ensuring production capacity and controlling maintenance costs in mines and large-scale projects.

Core technical parameters

Model number SY1250C2C3KH is a unique configuration number for the slewing device of a Sany 125-ton mining excavator.
Main materials: The slewing bearing is made of 42CrMo/50Mn alloy structural steel, treated with medium-frequency quenching and soft-strip shaping process, resulting in excellent fatigue and impact resistance; the slewing motor and reducer housing are made of QT500-7 ductile iron, and the internal gears are made of 20CrMnTi alloy forgings, treated with carburizing and quenching, making them wear-resistant and corrosion-resistant; the seals are made of fluororubber (FKM).
Operating temperature: Adaptable to extreme outdoor environments in mines, with an operating temperature range of -30℃ to 55℃.
Key operating parameters: The slewing bearing is a three-row column-type raceway with internal gears, static capacity ≥32000kN, raceway diameter approximately 1200mm, and gear module 20mm; the drive configuration is dual hydraulic motors + planetary reducer, with a single motor rated torque ≥85kN·m, and the total output torque can meet the heavy-duty slewing requirements of hundreds of tons; the slewing speed is 5.0rpm, balancing operating efficiency and stability; the main circuit working pressure is 35-40MPa, suitable for high-pressure, high-flow hydraulic systems, with fast response and low pressure loss; the lubrication method is centralized forced lubrication, with a seal life ≥8000 hours, suitable for long-term continuous operation.
Structural Design: Utilizing a three-row column-type slewing bearing structure, it evenly distributes the vertical load, overturning moment, and lateral load across the entire machine, avoiding localized stress concentration and improving load-bearing stability. The dual-drive parallel design ensures smooth starting and braking, strong impact resistance, and effectively reduces slewing vibration. An integrated electro-hydraulic slewing system achieves precise flow distribution and slewing buffering, reducing operational impact and protecting structural components. A dedicated dustproof and waterproof sealing module with a multi-lip seal design resists high dust levels and rainwater erosion in mines, preventing oil leakage. A grease filler port facilitates on-site maintenance and reduces maintenance costs.
Shape and Dimensions: The overall structure is compact, with an outer diameter of approximately 1200mm, an inner diameter of approximately 980mm, and a thickness of approximately 280mm for the slewing bearing; the upper flange has a specification of φ1050×M24×16 holes, and the lower flange has a specification of φ1100×M22×18 holes, perfectly matching the slewing platform and underframe of a 125-ton excavator, and can be directly replaced for installation; the slewing motor and reducer are integrated and installed, with an overall length of 680mm, a width of 520mm, and a height of 450mm, adapting to the compact installation space of the entire machine.

Core functions and roles

As the “spinning backbone” of a 100-ton mining excavator, its core function is to bear the overturning moment, vertical load, and lateral load of the entire machine, while driving the upper excavator to rotate precisely 360°. This, combined with complex actions such as digging, lifting, and unloading, ensures continuous and accurate operation. In large open-pit mines, water conservancy projects, and port infrastructure, it achieves smooth start-up and micro-motion adjustment through dual-drive synchronous control, reducing structural impact. The optimized design of the three-row column-type slewing bearing significantly improves load-bearing capacity and service life, preventing structural damage due to heavy loads. Precise control of the electro-hydraulic system reduces energy consumption and component wear, while also providing fault warnings and reducing maintenance difficulty. This device directly determines the excavator’s slewing efficiency, operational safety, and overall service life, making it a core component for avoiding downtime and ensuring continuous mine production.

Applicable Scenarios

Widely used in ore mining and stripping operations in large open-pit mines (coal and metal mines), it is also suitable for large-scale water conservancy projects, port infrastructure, urban demolition, and other massive earthwork projects. It is particularly suitable for scenarios requiring 24-hour continuous operation under harsh conditions (high dust, high impact, large temperature differences), serving as a key component for large-scale mining and the timely progress of large-scale projects. Simultaneously, it is adaptable to commercial scenarios such as equipment leasing and EPC (Engineering, Procurement, and Construction) projects. Its high reliability and low maintenance requirements can significantly reduce operating costs and improve the return on investment for projects.

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1 SSY008347233 Slewing Platform
2. Platform Supervisor Lu
5 SSY004911131 1250 Cab Assembly
6. Rotary Mechanism
8 SSY007450352 Counterweight Assembly
9 10275621 Adjusting shims
10 10450540 Washer
11 SSY004981300 Counterweight Bolt
18 Body panel assembly

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