Specifications Precision grade JIS Grade N9 (JIS B 1702-1:1998) JIS Grade 5 (JIS B 1702:1976) Gear teeth Standard full depth Pressure angle 20 Material S45C Carbon Steel Heat treatment - Core hardness less than HB194 Surface hardness Surface treatment Black oxide Surface finishing Shaper Cut Datum reference surface for gear cutting Outside diameter

T1

Module 2

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Catalog No.	Module	No. of teeth	Internal dia.	Pitch dia.	Outside dia. of ring	Face width	Shape	Allowable torque (kgfm)		Allowable torque (Nm)		Backlash (mm)	Weight (kgf)	Catalog No.
	m	z	A	C	D	E		Bending strength	Surface durability	Bending strength	Surface durability
SIR2-120 [ DXF| DWG| 3D CAD] SIR2-200 [ DXF| DWG| 3D CAD]	2 2	120 200	236 396	240 400	286 446	20 20	T1 T1	42.13 69.03	7.018 11.18	413.1 676.9	68.82 109.6	0.180.37 0.2 0.41	3 4.8	SIR2-120 SIR2-200

Module 2.5

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Catalog No.	Module	No. of teeth	Internal dia.	Pitch dia.	Outside dia. of ring	Face width	Shape	Allowable torque (kgfm)		Allowable torque (Nm)		Backlash (mm)	Weight (kgf)	Catalog No.
	m	z	A	C	D	E		Bending strength	Surface durability	Bending strength	Surface durability
SIR2.5-120 [ DXF| DWG| 3D CAD] SIR2.5-200 [ DXF| DWG| 3D CAD]	2.5 2.5	120 200	295 495	300 500	355 555	25 25	T1 T1	82.29 134.8	14.03 22.47	807 1322	137.6 220.4	0.2 0.41 0.220.46	5.5 8.9	SIR2.5-120 SIR2.5-200

Module 3

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Catalog No.	Module	No. of teeth	Internal dia.	Pitch dia.	Outside dia. of ring	Face width	Shape	Allowable torque (kgfm)		Allowable torque (Nm)		Backlash (mm)	Weight (kgf)	Catalog No.
	m	z	A	C	D	E		Bending strength	Surface durability	Bending strength	Surface durability
SIR3-120 [ DXF| DWG| 3D CAD] SIR3-160 [ DXF| DWG| 3D CAD]	3 3	120 160	354 474	360 480	424 544	30 30	T1 T1	142.2 187.5	24.89 32.13	1394 1839	244.1 315.1	0.220.45 0.220.45	10 12.1	SIR3-120 SIR3-160

CAUTION: Ring gears are easily susceptible to deformation, so careful handling is required.

NOTE: The allowable torques shown in the table are the calculated values according to JGMA Standards 401-01 and 402-02. The backlash values shown in the table are the theoretical values when the ring gears are meshed with a 30 tooth SS type spur gear. All dimensions shown in the above table(s) are listed in millimeters unless otherwise specified.

USEFUL HINT: SSR ring gears can be used as segment gears or as cornering racks by cutting the required section and finishing the ends. Please see the rack section for more information.