Need an internal ring gear with a higher tooth count? KHK SIR offers larger ring formats for compact gear mechanisms.
Customer: What is this series?
KAYO: SIR is the ring-shaped internal gear family, with the current selection covering 120, 160 and 200 teeth. KHK specifies S45C steel with cut teeth and allows secondary machining. Confirm any modification against the product drawing.
Customer: Which sizes are listed?
KAYO: The current Japanese table lists 6 models, with modules 2, 2.5, 3. The table below shows every listed model and its basic dimensions.
| Model | Module | Teeth | Outside diameter (mm) | Mass (kg) |
|---|---|---|---|---|
| SIR2-120 | 2 | 120 | 286 | 2.98 |
| SIR2-200 | 2 | 200 | 446 | 4.80 |
| SIR2.5-120 | 2.5 | 120 | 355 | 5.55 |
| SIR2.5-200 | 2.5 | 200 | 555 | 8.94 |
| SIR3-120 | 3 | 120 | 424 | 9.28 |
| SIR3-160 | 3 | 160 | 544 | 12.1 |
Customer: Can I use any pinion with the same module?
KAYO: Matching module is only the starting point. Check pinion tooth count, pressure angle, center distance and tooth interference. Involute, trochoid and trimming interference can limit the usable combination or assembly direction. Review KHK's mating-pinion guidance before finalizing the pair.
Customer: Where would I consider this gear?
KAYO: Internal gears are used in planetary arrangements and other compact reduction mechanisms. SIR provides a large tooth count in a ring format. Suitability depends on the complete gear train, mounting rigidity, lubrication, speed and load.
Customer: What information should I send for an enquiry?
KAYO: Please send the full SIR model code, quantity, mating pinion details, mounting requirements and operating conditions. We can discuss the specification and availability for your application. Manufacturer torque values depend on their stated calculation conditions and should be checked for the actual duty.
References: KHK SIR official model selection table | KHK internal gear range | KHK internal gear selection guidance. Confirm final dimensions against the latest manufacturer drawing.