Reparatur von Laufbahnablösungen und gebrochenen Zähnen von Baggerdrehkränzen

Slewing rings are critical components in engineering machinery, enabling rotational movement in excavators and other heavy equipment. However, due to manufacturing defects or external factors, these bearings can experience raceway peeling and broken teeth, leading to operational issues. This article provides a detailed guide on identifying and repairing these problems to ensure the longevity and efficiency of your equipment.

Einführung

Excavator slewing rings are essential for the smooth rotational function of heavy machinery. Over time, these components may suffer from raceway peeling and broken teeth due to material defects or external damage. Addressing these issues promptly and effectively can prevent further damage and costly replacements. This guide covers the symptoms of raceway peeling, methods for repairing damaged raceways, and techniques for fixing broken teeth.

Identifying Raceway Peeling in Excavator Slewing Rings

Raceway peeling can be challenging to detect externally, but certain symptoms can indicate this issue. Based on extensive experience, the following signs suggest raceway peeling:

• Unusual Noise: A “clack-clack” sound when the machine is loaded and rotating.
• Inconsistent Rotation Speed: Uneven or significantly reduced speed in a particular direction accompanied by slight vibration.
• High Motor Temperature or Current: Elevated temperature or current in the rotating motor.
• Damaged Keyway: The keyway of the rotating motor may be crushed due to coupling issues.

If these symptoms are present, it is crucial to repair the peeling promptly to prevent further damage and potential scrapping of the entire slewing ring.

Repairing Raceway Peeling

Steps for Repairing Raceway Peeling

1. Disassembly and Cleaning:

• Remove the rollers or steel balls to separate the inner and outer rings.
• Clean the raceway thoroughly with gasoline.

1. Grinding and Preparation:

• Use a grinding machine to remove the cracked hardened layer around the peeling area.
• Flatten the bottom of the peeling area.

1. Preheating and Welding:

• Preheat the area needing repair with a welding torch.
• Use a medium carbon steel welding rod for the repair, ensuring the weld is 1-2mm higher than the raceway surface.
• For large peeling areas, weld in layers and segments to prevent excessive heat buildup and deformation.

1. Cooling and Finishing:

• Insulate the weld area to allow gradual cooling.
• Grind the weld layer to level it with the raceway surface.
• Polish with oilstone or metallographic emery cloth until the surface matches the normal raceway height.

1. Reassembly:

• Clean the raceway and rollers (or steel balls) with gasoline.
• Apply lubricating grease and reassemble the components.

Following this method ensures that the raceway operates smoothly even after long-term use.

Repairing Broken Teeth in Slewing Rings

Causes and Repair Methods

Causes of Broken Teeth

Broken teeth in slewing rings can result from:

• Material Defects: Issues like sand inclusions or interlayers that weaken the gear’s bending resistance.
• Foreign Objects: Stones or steel bars embedded in the gear mesh position, causing increased local bending stress.

Local Welding Repair

1. Vorbereitung:

• Grind the damaged area with a hand-held grinding wheel and clean it with gasoline.

1. Preheating and Welding:

• Preheat the area with a welding torch.
• Use a medium carbon steel welding rod to weld the tooth prototype, making it 1-2mm higher than the tooth surface.

1. Shaping and Finishing:

• Use a tooth profile template to shape the tooth until it meets the requirements.
• For whole tooth damage, cut along the tooth root and fit a tooth from a scrapped ring, ensuring proper alignment.

1. Final Assembly:

• Weld the replacement tooth in place, smooth the weld with files, and ensure stable gear meshing.

Schlussfolgerung

Repairing raceway peeling and broken teeth in excavator slewing rings is crucial for maintaining the performance and longevity of heavy machinery. By following the detailed methods outlined in this guide, you can effectively address these issues, ensuring reliable operation and reducing downtime.

Abschnitt "Fragen und Antworten

Q: How often should the Excavator Slewing Ring sealing ring be replaced?

A: The replacement frequency depends on the excavator’s usage and operating conditions. Regular inspections and timely replacement when signs of wear or damage are detected are recommended. For machines operating in harsh environments or under heavy loads, more frequent inspections may be necessary to ensure optimal performance.

Q: What are the signs of a failing sealing ring?

A: Signs of a failing sealing ring include hydraulic oil leakage, abnormal noises, vibrations during operation, and visible wear or damage to the sealing ring. If any of these symptoms are observed, it is crucial to inspect the sealing ring and replace it if necessary to prevent further damage and maintain machine performance.

Q: Can I replace the sealing ring myself, or should I hire a professional?

A: While it is possible to replace the sealing ring yourself, it is recommended to hire a professional if you lack the necessary tools, skills, or experience. Proper installation is critical to ensure the sealing ring functions correctly and to avoid potential damage to the slewing ring or other components. Hiring a professional ensures the job is done accurately and efficiently, reducing the risk of future issues.