Internal Gear Description
Internal gears are a specialized type of gear with teeth that are cut on the inner surface of a cylindrical wheel, in contrast to external gears, which have teeth on their outer surface. This unique design allows internal gears to mesh neatly with external gears or pinions, creating compact and efficient gear systems.
Types:
Spur Internal Gears: Have straight teeth and are used for parallel shafts.
Helical Internal Gears: Have angled teeth, allowing for smoother and quieter operation.
Advantages of Internal Gears
Compact Design:
Internal gears allow for a more compact arrangement of drive mechanisms compared to external gears, making them ideal for space-constrained applications.
Key Features
High Load Capacity
They can carry significant loads due to the larger contact area between the teeth, leading to improved strength and durability.
Reduced Axial Thrust
Internal gear arrangements generally produce less axial thrust compared to external gears, which can enhance system stability.
Smooth Operation
Helical internal gears, in particular, provide smoother and quieter operation due to gradual engagement of the teeth.
Applications of internal gears:
1) Gearboxes
2) Planetary Gear Systems
3) Robotics and Automation
4) Mechanical Drives
Manufacturing Method of Internal Gear
Gear Shaping
Description: Involves a shaping machine that uses a reciprocating cutter to remove material and form the gear teeth.
Advantages: Can produce gears of various sizes and tooth profiles; effective for low-volume runs and custom gears.
Gear Broaching
Description: Gear broaching is a machining process used to create gears and other features on a workpiece by removing material with a broaching tool. This process is particularly efficient for producing internal and external gears with high precision.
Advantages: High Precision: Gear broaching produces gears with tight tolerances and excellent surface finishes.
Efficiency: It is a fast process, allowing for the production of large quantities of gears in a relatively short time
Gear Grinding
Description: Involves using a grinding wheel to refine the tooth profile and achieve precise dimensions and surface finishes.
Advantages: Provides high accuracy and smooth surface finishes; often used as a secondary process after hobbing or shaping.
Common Steel Code
Grades Comparison
| CHINA/GB | ISO | ROCT | ASTM | JIS | DIN |
| 45 | C45E4 | 45 | 1045 | S45C | CK45 |
| 40Cr | 41Cr4 | 40X | 5140 | SCr440 | 41Cr4 |
| 20CrMo | 18CrMo4 | 20ХМ | 4118 | SCM22 | 25CrMo4 |
| 42CrMo | 42CrMo4 | 38XM | 4140 | SCM440 | 42CrMo4 |
| 20CrMnTi | 18XГT | SMK22 | |||
| 20Cr2Ni4 | 20X2H4A | ||||
| 20CrNiMo | 20CrNiMo2 | 20XHM | 8720 | SNCM220 | 21NiCrMo2 |
| 40CrNiMoA | 40XH2MA/ 40XHMA | 4340 | SNCM439 | ||
| 20CrNi2Mo | 20NiCrMo7 | 20XH2MA | 4320 | SNCM420 | |
| 17CrNiMo6 | |||||
| 18CrNiMo7 |
Common Heat Treatment Process
Heat treatment is a controlled process used to alter the physical and sometimes chemical properties of materials, particularly metals. It can enhance properties such as hardness, strength, toughness, and ductility. Here are some common heat treatment processes:
01
Annealing
Purpose
To soften the material, improve ductility, and relieve internal stresses.
Process
Heating the metal to a specific temperature and then cooling it slowly, usually in air or in a furnace.
02
Quenching
Purpose
To increase hardness and strength.
Process
Heating the metal to a high temperature and then rapidly cooling it in water, oil, or air. This process can induce stresses in the material.
03
Tempering
Purpose
To reduce brittleness after quenching and improve toughness.
Process
Heating the quenched metal to a lower temperature (below its critical point) and then cooling it, allows for some of the internal stresses to be relieved.
04
Normalizing
Purpose
To refine the grain structure and enhance mechanical properties.
Process
Heating the steel above its critical temperature and allowing it to cool in air. This results in a uniform microstructure.
05
Hardening
Purpose
To increase hardness and wear resistance.
Process
Involves quenching, followed by tempering to achieve desired hardness levels, commonly applied to tool steels.
06
Case Hardening
Purpose
To harden the surface of a material while maintaining a softer, ductile core.
Process
Methods include carburizing (adding carbon) or nitriding (adding nitrogen) to the surface layer, followed by quenching.
Manufacturing Capacity of Internal Gear
| Item | Description |
| Gear Type | Internal Gear |
| Module (m) | Max 28 |
| DP | 0.75 |
| Pressure angle (α） | 20 Deg |
| Helix angle (β) | Max 35 Deg |
| Number of teeth (z) | |
| Facewidth (b) | 500mm |
| Profile shift coefficient (x) | Customized |
| Reference diameter (d) | Customized |
| Face width (b) | Max 3 Meter |
Quality Control of Internal Gear
Quality control is essential in the manufacturing of spur gears to ensure they meet specified standards and function effectively in their applications. The following are key aspects and methods used in the quality control process for spur gears:
