What are the fixes when there is a gluing failure in the inner ring gear?

What is inner gear ring?

The inner ring gear is a kind of annular mechanical transmission component, with dense tooth grooves distributed on the inner side, and power transmission and speed conversion are realized by meshing with external gears or planetary gears. Its structure is divided into two kinds of drum teeth and straight teeth, the drum tooth design can improve the angular displacement bearing capacity and torque transmission efficiency, and the materials are mostly wear-resistant engineering plastics, metals or composite materials, which have the characteristics of high precision, low noise and long life. It is widely used in the field of industrial equipment transmission system, automobile gearbox and precision machinery, such as forging machinery, industrial robot joints, etc., with the advantages of small size, high transmission efficiency and strong adaptability, and is an indispensable core component in modern equipment manufacturing.

Inner ring gear features

As the core component of high-efficiency transmission, the characteristics of the internal gear ring can be summarized into the following five dimensions:

1. Structural design advantages

Adopting a closed transmission structure with annular cogging and external gear meshing, the drum tooth design can absorb shaft offset (allowable ±1° angular displacement), and the impact resistance is increased by more than 30% compared with straight teeth

Precision tooth shaping (ISO 6-7 accuracy) ensures smooth engagement and transmission errors within ±15μm

2. Breakthrough in material properties

Metal ring gear: high-strength alloy steel (20CrMnTi) has been carburized and quenched, with a tooth surface hardness of HRC58-62 and a wear life of more than 100,000 hours

Non-metallic ring gears: Glass-reinforced nylon 66 (GF30) has a density of only 1.3 g/cm³ and a self-lubricating coefficient of 0.12, resulting in a 40% weight reduction and maintenance-free

3. Optimization of transmission efficiency

Transmission efficiency of more than 98.5% (planetary drive system), 18% energy saving compared to belt drive

The torque density is up to 250 N・m/cm³ (metal ring gear), and 1200 N・m torque can be transmitted in a space of φ150 mm

4. Adaptability to working conditions

The operating temperature range is -40°C~+180°C, which meets the needs of cold and hot environments

The dynamic response time is < 50ms, which is suitable for precision control scenarios such as AGV robots

Salt spray corrosion resistance up to 1000 hours (neutral salt spray test) for offshore equipment

5. Modular design trends

Integrated design: The bearing housing, sealing structure and ring gear are integrated to reduce assembly errors

Quick-change interfaces: 70% reduction in service time thanks to standardized flange connections

Smart ring gears: Built-in temperature/stress sensors for predictive maintenance

These characteristics make the inner gear ring play a key role in the motor reducer of new energy vehicles (such as the Tesla Model 3 adopts a double inner gear ring structure), wind power speed increasing box (carrying 1.5MW torque), aerospace (resistant to -200°C cryogenic environment) and other fields, and its development direction is evolving in the direction of higher power density, lower noise (<65dB), and longer maintenance-free intervals (more than 8 years).

What are the fixes when there is a gluing failure in the inner ring gear?

When the gluing failure of the inner gear ring occurs, it is necessary to choose a targeted repair method according to the degree of damage, and the following is a systematic repair plan:

1. Slight gluing repair (wear depth< 0.1mm)

Honing of the tooth surface

Using a diamond honing wheel (particle size 80-120 mesh), the honing pressure is 0.3-0.5MPa

The flank flank convex peak was removed and the Ra≤0.8μm roughness was restored

The amount of honing is controlled at 0.05-0.1mm, and the tooth shape deviation < 10μm

Chemical polishing strengthened

A nitric acid-hydrofluoric acid mixture (3:1 volume ratio) is used at 40-50°C

The processing time is 3-5 minutes to form a 0.01-0.02mm passivation film

The residual compressive stress on the surface is increased to more than -300MPa

Nano-coating restoration

Supersonic Flame Spray (HVOF) WC-12Co coating

The coating thickness is 0.15-0.2mm, and the hardness is HV1200

The bonding strength > 70MPa, and the coefficient of friction is reduced to 0.08

2. Moderate gluing repair (wear depth 0.1-0.3mm)

Laser cladding technology

Fiber lasers (power 2-4kW, spot diameter 2-3mm)

Cladding material selected Ni60A alloy powder (particle size - 150+325 mesh)

Process parameters: scanning speed 5-8mm/s, defocus 100mm

Cladding hardness HRC55-60 with dilution <5%

Brush plating repair

Substrate treatment: 30 seconds of electroclean solution (pH 11-12) and 15 seconds of activation solution (pH 2-3).

Deposition nickel-phosphorus alloy plating with a thickness of 0.2-0.3mm

The bonding strength > 40MPa, and the microhardness is HV500

Ionic nitriding modification

Glow ion nitriding furnace at 520-540°C for 8-10 hours

The depth of the nitride layer is 0.3-0.4mm, and the hardness is HV800-1000

Residual compressive stress>-500MPa

3. Severe gluing repair (wear depth>0.3mm)

Local tooth profile reconstruction

Five-axis linkage CNC milling, according to the original tooth profile data to reconstruct the tooth surface

Leave a 0.2mm grinding allowance, and then precision grind to IT6 level accuracy

Case hardening (induction heating power density > 5kW/cm²)

Integral ring gear replacement

20CrNi2MoA (hardenability J9≥38HRC)

The hardness of the tooth surface is HRC58-62, and the depth of the hardened layer ≥ 2.5mm

Electron beam welding (EBW) is used to splice the original part, and the weld strength > 90% of the base metal

Additive manufacturing replacement

Selective Laser Melting (SLM) technology using 17-4PH stainless steel powder

The molding accuracy is ±0.05mm, and the hardness after heat treatment is HRC40-45

Surface peening strengthened (Almen A250, 100% coverage)

4.The detection standard after repair

Tooth profile accuracy detection

Total profile deviation< 12 μm (ISO 1328 class 6)

Tooth direction deviation < 10μm/100mm

Material performance testing

Adhesion strength between cladding layer and substrate> 40MPa (shear test)

The microhardness gradient ≤ 50HV/0.1mm

Dynamic performance verification

No-load running test: 1000 rpm for 2 hours, temperature rise < 15°C

Load test: 1.2 times rated torque, vibration intensity < 1.8mm/s

5. Typical restoration cases

The inner gear ring of a wind power speed box is glued and repaired by laser cladding:

The thickness of the cladding layer is 0.25mm, and the hardness is HRC58

The tooth roughness Ra was restored from 2.5 μm to 0.6 μm

1.2% more efficient and 5dB less noise after repair

6. Maintenance suggestions

On-line monitoring: Install a tooth surface temperature sensor (accuracy ±0.5°C) and an oil-liquid iron spectrometer

Lubrication optimization: use of fully synthetic ester oil (viscosity index > 150, flash point > 240°C)

Periodic maintenance: Fluorescence flaw detection on the flank every 2000 hours, crack detection sensitivity ≤ 0.1mm

Inner gear ring supplier

LTZCprovides inner gear ring. If you are looking for a supplier of  inner gear ring, please contact us for the latest quotation.