This is a high-attenuation rubber coupling designed for servo and stepper motors. The newly developed rubber element provides high attenuation and low reaction force. It absorbs vibrations more quickly than flexible couplings that use metal in their elastic components. This helps suppress resonance phenomena that are a concern with stepper motors and similar devices.

specifications

models	Shape TYPE	Permissible (operating) torque [N·m]	Permissible Tolerance			Max. rotation speed [^min⁻¹]	Torsional Stiffness [N·m/rad]	Moment of Inertia [kg·m²]	Mass [kg]
			eccentricity	angular misalignment	axial direction
			[mm]	[°]	[mm]
SFR-005SA1	C	0.6	0.15	1.5	±0.2	10,000	30	0.32×10⁻⁶	0.009
SFR-010SA1	C	1	0.15	1.5	±0.2	10,000	47	0.73×10−6	0.014
SFR-020SA1	C	2	0.15	1.5	±0.2	10,000	178	3.11×10−6	0.032
SFR-025SA1	C	4	0.2	1.5	±0.3	10,000	254	4.88×10−6	0.038
SFR-030SA1	A	5	0.2	1.5	±0.3	10,000	396	6.62×10⁻⁶	0.048
SFR-030SA1	B	5	0.2	1.5	±0.3	10,000	396	8.65×10−6	0.054
SFR-030SA1	C	5	0.2	1.5	±0.3	10,000	396	10.76×10⁻⁶	0.063
SFR-035SA1	C	10	0.2	1.5	±0.3	10,000	607	26.98×10⁻⁶	0.105
SFR-040SA1	A	12	0.2	1.5	±0.3	10,000	1,128	25.37×10⁻⁶	0.103
SFR-040SA1	B	12	0.2	1.5	±0.3	10,000	1,128	31.96×10⁻⁶	0.114
SFR-040SA1	C	12	0.2	1.5	±0.3	10,000	1,128	38.64×10⁻⁶	0.128
SFR-050SA1	A	25	0.2	1.5	±0.3	10,000	2,775	85.36×10⁻⁶	0.216
SFR-050SA1	B	25	0.2	1.5	±0.3	10,000	2,775	105.75 × 10⁻⁶	0.234
SFR-050SA1	C	25	0.2	1.5	±0.3	10,000	2,775	128.36×10⁻⁶	0.263

The shape type (A, B, or C) is automatically determined based on the combination of bore sizes you select, so you cannot specify it.
The permissible torque may be limited by the Holding Power of the shaft fastening section, so please check the “standard bore size.”
The max. rotation speed does not take dynamic balance into account.
The torsional stiffness values are the analytical values for the element section at 20°C.
The moment of inertia and mass are the values corresponding to the maximum bore size.

Dimensions

三木プーリのサーボフレックスラバー SFR-SA1タイプゴム・樹脂カップリング寸法図（防振・衝撃吸収・サーボモータ用軸継手）

Unit [mm]
models	Shape TYPE	d1		d2		D	N	L	LF	LP	S	A1	A2	C	d3	M Quantity - nominal size	Tightening Torque [N·m]
models	Shape TYPE	Minimum	Maximum	Minimum	Max	D	N	L	LF	LP	S	A1	A2	C	d3	M Quantity - nominal size	Tightening Torque [N·m]
SFR-005SA1	C	3	5	3	6	16	-	22.7	7.85	6.4	0.3	-	4.8	2.5	5.5	1-M2	0.4–0.5
SFR-010SA1	C	3	7	3	8	19	-	25.4	9.15	6.6	0.25	-	5.8(6)	3.15	7.5	1–M2.5 (M2)	1.0–1.1 (0.4–0.5)
SFR-020SA1	C	4	10	4	11	26	-	31.8	10.75	8.9	0.7	-	9.5	3.3	10.5	1–M2.5	1.0–1.1
SFR-025SA1	C	5	13	5	14	29	-	32.3	10.75	9.4	0.7	-	11	3.3	13.5	1–M2.5	1.0–1.1
SFR-030SA1	A	5	10	5	10	34	21.6	37.8	12.4	11	1	8	-	3.75	15.5	1-M3	1.5–1.9
SFR-030SA1	B	5	10	Greater than 10	16	34	21.6	37.8	12.4	11	1	8	12.5	3.75	15.5	1-M3	1.5–1.9
SFR-030SA1	C	Greater than 10	15	Greater than 10	16	34	-	37.8	12.4	11	1	-	12.5	3.75	15.5	1-M3	1.5–1.9
SFR-035SA1	C	6	18	6	19	39	-	48	15.5	15	1	-	14	4.5	18.5	1-M4	3.4–4.1
SFR-040SA1	A	8	15	8	15	44	29.6	48	15.5	15	1	11	-	4.5	23.5	1-M4	3.4–4.1
SFR-040SA1	B	8	15	Greater than 15	24	44	29.6	48	15.5	15	1	11	17	4.5	23.5	1-M4	3.4–4.1
SFR-040SA1	C	Greater than 15	22	Greater than 15	24	44	-	48	15.5	15	1	-	17	4.5	23.5	1-M4	3.4–4.1
SFR-050SA1	A	8	19	8	19	56	38	59.8	20.5	17.4	0.7	14.5	-	6	29.5	1-M5	7.0–8.5
SFR-050SA1	B	8	19	Over 19	30	56	38	59.8	20.5	17.4	0.7	14.5	22	6	29.5	1-M5	7.0–8.5
SFR-050SA1	C	Greater than 19	28	Over 19	30	56	-	59.8	20.5	17.4	0.7	-	22	6	29.5	1-M5	7.0–8.5

The shape type (A, B, or C) is automatically determined based on the combination of bore sizes you select, so you cannot specify it.
The d3 dimension is the inner diameter of the element. If the d2 dimension exceeds this value, the shaft can only be inserted into the hub on the d2 side up to the LF dimension.
The nominal size for Clamping Bolt M is the quantity followed by the thread size; the quantity refers to the number of hubs on one side.

standard bore size

Standard (Optional) Bore Sizes d1 and d2 [mm] and Permissible (Operating) Torque [N·m]
Nominal Bore Size			3	4	5	6	6.35	7	8	9	9.525	10	11	12	13	14	15	16	17	18	19	20	22	24	25	28	30
Shaft Tolerance	h7 (h6·g6)	B	●	●	●	●	●	●	●	●	●	●	●	●	●	●	●	●	●	●	●	●	●	●	●	●	●
Shaft Tolerance	j6 (optional)	J																			〇		〇	〇		○
Shaft Tolerance	k6 (optional)	K							〇	〇						〇		○			〇		〇	〇
Compatible Bore Sizes by Model	SFR-005SA1	d1	●	●	●
Compatible Bore Sizes by Model	SFR-005SA1	d2	●	●	●	●
Compatible Bore Sizes by Model	SFR-010SA1	d1	●	●	●	●	●	●
Compatible Bore Sizes by Model	SFR-010SA1	d2	●	●	●	●	●	●	●
Compatible Bore Sizes by Model	SFR-020SA1	d1		●	●	●	●	●	●	●	●	●
Compatible Bore Sizes by Model	SFR-020SA1	d2		●	●	●	●	●	●	●	●	●	●
Compatible Bore Sizes by Models	SFR-025SA1	d1			2.1	●	●	●	●	●	●	●	●	●
Compatible Bore Sizes for Each Model	SFR-025SA1	d2			2.1	●	●	●	●	●	●	●	●	●	●
Compatible Bore Sizes by Model	SFR-030SA1	d1			2.8	3.4	●	●	●	●	●	●	●	●	●	●
Compatible Bore Sizes for Each Model	SFR-030SA1	d2			2.8	3.4	●	●	●	●	●	●	●	●	●	●	●
Compatible Bore Sizes by Models	SFR-035SA1	d1				5	5	6.6	●	●	●	●	●	●	●	●	●	●	●	●	●	●
Compatible Bore Sizes for Each Model	SFR-035SA1	d2				5	5	6.6	●	●	●	●	●	●	●	●	●	●	●	●	●	●	●
Compatible Bore Sizes by Model	SFR-040SA1	d1							9	●	●	●	●	●	●	●	●	●	●	●	●	●	●
Compatible Bore Sizes for Each Model	SFR-040SA1	d2							9	●	●	●	●	●	●	●	●	●	●	●	●	●	●	●
Compatible Bore Sizes by Models	SFR-050SA1	d1							18	20	22	22	●	●	●	●	●	●	●	●	●	●	●	●	●	●
Compatible Bore Sizes by Model	SFR-050SA1	d2							18	20	22	22	●	●	●	●	●	●	●	●	●	●	●	●	●	●	●

The standard bore size for shaft tolerance h7 (h6, g6) is nominal size B.
For shaft tolerances j6 and k6: The J and K designations are optional; only the circle-marked bore sizes are supported.
The bore sizes indicated by the ● symbol and numerical values in the corresponding columns are standard bore sizes. For bore sizes not listed in the table above, we may be able to accommodate them on a case-by-case basis, so Contact Us.
For holes with numerical values, the permissible (operating) torque is limited by the holding power at the shaft fastening section due to the small bore size. The numerical values indicate the permissible (operating) torque [N·m].

三木プーリのサーボフレックスラバー SFRモデル SA1タイプゴム・樹脂カップリングご注文時の型式構成説明図

Taper Shaft Compatible (SFR-□SA1) [BC]

By attaching a tapered adapter to the tapered shaft of the Servo motor, it can be locked using a clamping hub.

Specifications (Tapered Shaft)

models	Shape TYPE	Permissible (operating) torque [N·m]	Permissible Tolerance			Max. rotation speed [^min⁻¹]	Torsional Stiffness [N·m/rad]	Axial stiffness [N/mm]	Moment of inertia [kg·m²]	Mass [kg]
			eccentricity	angular misalignment	axial direction
			[mm]	［°］	[mm]
SFR-040SA1-□B-11BC	B	12	0.2	1.5	±0.3	10,000	1,128	605	35.95 × 10⁻⁶	0.162
SFR-040SA1-□B-11BC	C	12	0.2	1.5	±0.3	10,000	1,128	605	42.24 × 10⁻⁶	0.174
SFR-050SA1-□B-11BC	B	25	0.2	1.5	±0.3	10,000	2,775	658	111.04 × 10⁻⁶	0.297
SFR-050SA1-□B-11BC	C	25	0.2	1.5	±0.3	10,000	2,775	658	133.26 × 10⁻⁶	0.325
SFR-050SA1-□B-14BC	B	25	0.2	1.5	±0.3	10,000	2,775	658	118.21 × 10⁻⁶	0.328
SFR-050SA1-□B-14BC	C	25	0.2	1.5	±0.3	10,000	2,775	658	141.08 × 10⁻⁶	0.369
SFR-050SA1-□B-16BC	B	25	0.2	1.5	±0.3	10,000	2,775	658	124.92 × 10⁻⁶	0.366
SFR-050SA1-□B-16BC	C	25	0.2	1.5	±0.3	10,000	2,775	658	147.53 × 10⁻⁶	0.395

The shape type (B or C) is automatically determined based on the combination of bore sizes you select, so you cannot specify it.
Since the permissible (operating) torque may be limited by the holding power of the shaft fastening section, please check the “standard bore size” to confirm.
The max. rotation speed does not take dynamic balance into account.
The torsional stiffness values are the analytical values for the element section at 20°C.
The moment of inertia and mass are the values at the maximum bore diameter.

Dimensions (Tapered Shaft)

三木プーリのサーボフレックスラバーSFRモデルSA1タイプゴム・樹脂カップリング寸法図取付寸法および軸径寸法を示す寸法図（テーパ軸対応オプション）

Unit [mm]
models	d2	W	T	WA	LA	dA	DA	LL	D	L	LF	C	A1	A2	M Quantity - nominal size
SFR-040SA1-□B-11BC	11	4	12.2	18	16	17	22	58	44	48	15.5	4.5	11	17	1-M4
SFR-050SA1-□B-11BC	11	4	12.2	18	16	17	22	64.8	56	59.8	20.5	6	14.5	22	1-M5
SFR-050SA1-□B-14BC	14	4	15.1	24	19	22	28	69.8	56	59.8	20.5	6	14.5	22	1-M5
SFR-050SA1-□B-16BC	16	5	17.3	24	29	26	30	79.8	56	59.8	20.5	6	14.5	22	1-M5

For dimensions other than those listed above, please refer to the SFR MODEL specifications.

Standard Boring (Tapered Shaft)

Standard (Optional) Bore Size d1 [mm] and Permissible (Operating) Torque [N·m]
Nominal Bore Size		8	9	9.525	10	11	12	13	14	15	16	17	18	19	20	22	24	25	28	30
Shaft Tolerance h7 (h6, g6)	B	●	●	●	●	●	●	●	●	●	●	●	●	●	●	●	●	●	●	●
Shaft tolerance j6 (optional)	J													○		○	○		○
Shaft Tolerance k6 (Optional)	K	○	○						○		○			○		○	○
SFR-040SA1-□B-11BC		9	●	●	●	●	●	●	●	●	●	●	●	●	●	●	●
SFR-050SA1-□B-11BC		18	20	22	22	●	●	●	●	●	●	●	●	●	●	●	●	●	●	●
SFR-050SA1-□B-14BC		18	20	22	22	●	●	●	●	●	●	●	●	●	●	●	●	●	●	●
SFR-050SA1-□B-16BC		18	20	22	22	●	●	●	●	●	●	●	●	●	●	●	●	●	●

The standard bore size for shaft tolerance h7 (h6, g6) is nominal B.
For shaft tolerances j6 and k6: The nominal sizes for J and K are optional; only the bore sizes marked with a circle are supported.
The bore sizes indicated by the ● symbol and numerical values in the corresponding columns are standard bore sizes. For bore sizes not listed in the table above, we may be able to accommodate them on a case-by-case basis, so Contact Us.
For holes with numerical values, the permissible (operating) torque is limited by the Holding Power at the shaft fastening section due to the small bore size. The numerical values indicate the permissible (operating) torque [N·m].

三木プーリのサーボフレックスラバー SFRモデル SA1タイプゴム・樹脂カップリングご注文時の型式構成説明図（テーパ軸対応オプション）

SFR-□SA1: Keyway Compatible

If you choose to use a shaft with a key, we will perform Keyway Machining on the clamping hub upon request.

Keyway Machining Specifications

三木プーリのサーボフレックスラバーSFRモデルSA1タイプゴム・樹脂カップリング寸法図取付寸法および軸径寸法を示す寸法図（キー溝加工対応オプション）

Unit [mm]
Keyway width: Compliant with H9 standard														Keyway width: Compliant with JS9 standard
Nominal Bore Size				Bore Size d1・d2	Keyway width W1 and W2	Keyway height T1 and T2	Nominal Bore Size				Bore sizes d1 and d2	Keyway width W1 and W2	Keyway height T1 and T2	Nominal Bore Size				Bore sizes d1 and d2	Keyway width W1 and W2	Keyway height T1 and T2	Nominal Bore Size				Bore sizes d1 and d2	Keyway width W1 and W2	Keyway height T1 and T2
Shaft diameter	Shaft Tolerance						Shaft diameter	Shaft Tolerance						Shaft diameter	Shaft Tolerance						Shaft diameter	Shaft Tolerance
Shaft diameter	h7	j6	k6				Shaft diameter	h7	j6	k6				Shaft diameter	h7	j6	k6				Shaft diameter	h7	j6	k6
8	BH	－	KH	8	3 + 0.0250	9.4 + 0.30	17	BH	－	－	17	5 + 0.0300	19.3 + 0.30	8	BJ	－	KJ	8	3 ± 0.0125	9.4 + 0.30	17	BJ	－	－	17	5 ± 0.0150	19.3 + 0.30
9	BH	－	KH	9	3 + 0.0250	10.4 + 0.30	18	BH	－	－	18	6 + 0.0300	20.8 + 0.30	9	BJ	－	KJ	9	3 ± 0.0125	10.4 + 0.30	18	BJ	－	－	18	6 ± 0.0150	20.8 + 0.30
10	BH	－	－	10	3 + 0.0250	11.4 + 0.30	19	BH	JH	KH	19	6 + 0.0360	21.8 + 0.30	10	BJ	－	－	10	3 ± 0.0125	11.4 + 0.30	19	BJ	JJ	KJ	19	6 ± 0.0180	21.8 + 0.30
11	BH	－	－	11	4 + 0.0300	12.8 + 0.30	20	BH	－	－	20	6 + 0.0360	22.8 + 0.30	11	BJ	－	－	11	4 ± 0.0150	12.8 + 0.30	20	BJ	－	－	20	6 ± 0.0180	22.8 + 0.30
12	BH	－	－	12	4 + 0.0300	13.8 + 0.30	22	BH	JH	KH	22	6 + 0.0360	24.8 + 0.30	12	BJ	－	－	12	4 ± 0.0150	13.8 + 0.30	22	BJ	JJ	KJ	22	6 ± 0.0180	24.8 + 0.30
13	BH	－	－	13	5 + 0.0300	15.3 + 0.30	24	BH	JH	KH	24	8 + 0.0360	27.3 + 0.30	13	BJ	－	－	13	5 ± 0.0150	15.3 + 0.30	24	BJ	JJ	KJ	24	8 ± 0.0180	27.3 + 0.30
14	BH	－	KH	14	5 + 0.0300	16.3 + 0.30	25	BH	－	－	25	8 + 0.0360	28.3 + 0.30	14	BJ	－	KJ	14	5 ± 0.0150	16.3 + 0.30	25	BJ	－	－	25	8 ± 0.0180	28.3 + 0.30
15	BH	－	－	15	5 + 0.0300	17.3 + 0.30	28	BH	JH	－	28	8 + 0.0360	31.3 + 0.30	15	BJ	－	－	15	5 ± 0.0150	17.3 + 0.30	28	BJ	JJ	－	28	8 ± 0.0180	31.3 + 0.30
16	BH	－	KH	16	5 + 0.0300	18.3 + 0.30	30	BH	－	－	30	8 + 0.0360	33.3 + 0.30	16	BJ	－	KJ	16	5 ± 0.0150	18.3 + 0.30	30	BJ	－	－	30	8 ± 0.0180	33.3 + 0.30

We can accommodate specifications not listed in the table above. Contact Us for more information.

Standard Bore Size (Keyway)

Standard (Optional) Bore Size d1 [mm] and Permissible (Operating) Torque [N·m]
Nominal Bore Size		8	9	9.525	10	11	12	13	14	15	16	17	18	19	20	22	24	25	28	30
Shaft Tolerance h7 (h6, g6)	B	●	●	●	●	●	●	●	●	●	●	●	●	●	●	●	●	●	●	●
Shaft tolerance j6 (optional)	J													○		○	○		○
Shaft Tolerance k6 (Optional)	K	○	○						○		○			○		○	○
SFR-030SA1	d1	●	●	●	●	●	●	●	●	●
SFR-030SA1	d2	●	●	●	●	●	●	●	●	●	●
SFR-035SA1	d1	●	●	●	●	●	●	●	●	●	●	●	●
SFR-035SA1	d2	●	●	●	●	●	●	●	●	●	●	●	●	●
SFR-040SA1	d1	9	●	●	●	●	●	●	●	●	●	●	●	●	●	●
SFR-040SA1	d2	9	●	●	●	●	●	●	●	●	●	●	●	●	●	●	●
SFR-050SA1	d1	18	20	22	●	●	●	●	●	●	●	●	●	●	●	●	●	●	●
SFR-050SA1	d2	18	20	22	●	●	●	●	●	●	●	●	●	●	●	●	●	●	●	●

三木プーリのサーボフレックスラバー SFRモデル SA1タイプゴム・樹脂カップリングご注文時の型式構成説明図（キー溝加工オプション）