Next-Gen

SRH Series – WPU-SRH-BD

Hollow Shaft Unit

The Next-Gen WPU-SRH Series is a compact hollow-shaft gearhead that combines Nidec’s advanced FLEXWAVE gear technology with integrated torque and temperature sensing for superior performance and control. Designed for high-torque, zero-backlash operation, it offers exceptional precision, rigidity, and durability in a slim form factor.

The large hollow input shaft simplifies cable or shaft routing, while the robust cross-roller output bearing and flange allow direct load mounting — eliminating external bearings. TÜV SÜD safety certification ensures compliance and reliability across robotics, automation, aerospace, medical, and precision equipment applications.

Features

Zero backlash, high torque, and superior torsional stiffness
Built-in multi sensor for real-time torque and temperature monitoring
Large hollow input shaft for easy integration
Positioning accuracy
Direct-mount output flange with cross-roller bearing support
TÜV SÜD safety certified

Downloads

Selection Configurator

Smart-FLEXWAVE Catalog

Multi-Sensor Integration Features

Detects Output Torque
Detects Internal Temperature of Reducer

Ratio Matrix Availability

Frame Size	50 Reduction Ratio	80 Reduction Ratio	100 Reduction Ratio	120 Reduction Ratio	160 Reduction Ratio
35	✔	✔	✔	❌	❌
42	✔	✔	✔	✔	❌
50	✔	✔	✔	✔	✔
63	✔	✔	✔	✔	✔
80	✔	✔	✔	✔	✔

Reducer Specifications

Frame Size	Ratio R	Nominal Output Torque ^*1 [Nm]	Maximum Output Torque ^*2 [Nm]	Emergency Stop Torque ^*3 [Nm]	Nominal Input Speed ^*4 [r/min)	Maximum Input Speed ^*5 [r/min)	Life ^*6 [hours]
35	50	7	23	46	3000	8500	7692
35	80	10	30	61	3000	8500	7692
35	100	10	36	70	3000	8500	7692
42	50	21	44	91	3000	7300	7692
42	80	29	56	113	3000	7300	7692
42	100	31	70	143	3000	7300	7692
42	120	31	70	112	3000	7300	7692
50	50	33	73	127	3000	6500	7692
50	80	44	96	165	3000	6500	7692
50	100	52	107	191	3000	6500	7692
50	120	52	113	191	3000	6500	7692
50	160	52	120	191	3000	6500	7692
63	50	51	127	242	3000	5600	7692
63	80	82	178	332	3000	5600	7692
63	100	87	204	369	3000	5600	7692
63	120	87	217	395	3000	5600	7692
63	160	87	229	408	3000	5600	7692
80	50	99	281	497	3000	4800	7692
80	80	153	395	738	3000	4800	7692
80	100	178	433	841	3000	4800	7692
80	120	178	459	892	3000	4800	7692
80	160	178	484	892	3000	4800	7692

The maximum allowable value at the input rotation speed of 2000r/min
The maximum torque when starting and stopping.
The maximum torque when it receives shock.
The maximum average input speed.
The maximum input speed.
The life time at the input rotation speed of 2000 r/min and nominal output torque.

Torque Sensor Data

Features	Description	Notes
Rated torque	Equivalent to the maximum allowable torque of the reducer	-
Limit torque	Equivalent to the emergency stop torque of reducer	-
Durability	Equivalent to reducer	-
Measuring range (Full scale)	Determined by the size of the reducer	-
Non-linearity	±3% FS or less	Range to rated torque
Hysteresis	3% FS or less	Range to rated torque
Cross-axis sensitivity	±1% FS or less	Range to allowable moment of reducer
Temperature compensation	±0.05FS/°C	Use the built-in temperature sensor
Resolution	12-bit	Range: ±2000 LSB:Determined by the size of the reducer
Functional safety	PLd (Category 3) /ISO 13849-1 SIL2 /IEC 61508	Certification is expected in 2024

Temperature Sensor Data

Features	Description	Notes
Accuracy	±2°C	T.B.D.
Measuring range	0°C ~ 80°C	-
Resolution	0 ~ 800 bit	LSB: 0.1°C

General Data

Features	Description	Notes
Power supply voltage	DC24V+10%/-15%	-
Consumption current	0.06A or less	T.B.D.
Communication method	2-wire RS-485	-
Baud rate	3.0Mbps	-
Operating temperature limit	0°C ~ 80°C	-

Sensor Measurement Range

Frame	Ratio *^1**	Rated Lod [Nm]	Full Scale [Nm]	Full Scale [LSB]
35	50	23	± 50	0.025
35	80	30	± 50	0.025
35	100	36	± 50	0.025
42	50	44	± 100	0.050
42	80	56	± 100	0.050
42	100	70	± 100	0.050
42	120	70	± 100	0.050
50	50	73	± 150	0.075
50	80	96	± 150	0.075
50	100	107	± 150	0.075
50	120	113	± 150	0.075
50	160	120	± 150
63	50	127	± 300	0.150
63	80	178	± 300	0.150
63	100	204	± 300	0.150
63	120	217	± 300	0.150
63	160	229	± 300	0.150
80	50	281	± 600	0.300
80	80	395	± 600	0.300
80	100	433	± 600	0.300
80	120	459	± 600	0.300
80	160	484	± 600	0.300

“+” sign indicates clockwise (CW) torque.
LSB is an abbreviation for Least Significant Bit.

Smart-Flexwave Weight and Size

Model	Weight ^*1 [kg]	Outer Diameter of Cover A ^*2 [mm]	Thickness ^*3 [mm]
WPU-35-□-SRH-BD	0.72	+ 4	+ 7
WPU-42-□-SRH-BD	1.0	+ 4	+ 7
WPU-50-□-SRH-BD	1.4	+ 0	+ 5
WPU-63-□-SRH-BD	2.1	+ 0	+ 5
WPU-80-□-SRH-BD	4.2	+ 0	+ 5

Weight is almost same with based reducer.
Outer diameter of #35 and #42 is larger than based reducer ones.
Thickness increases with all models against based reducer.

Closed Type: Component

WPU-□-□-SRH-BD Dimensions

Frame Size	Weight Kg	Moment of Inertia x10^-4kgm²
35	0.78	0.0924
42	1.05	0.207
50	1.4	0.408
63	2.1	1.06
80	4.2	2.72

[mm]

Frame Size	LA	LB	LC	LD	LE	LF	LG	LH	LJ	LK	LL	LP	LQ
35	44	36	54	70	52.5	27.5	5	20	7.5	8	16	2.5	1.5
42	54	45	64	80	56.5	30	5	21.5	8.5	8.5	17	2.5	1.5
50	62	50	75	90	51.5	30	0	21.5	7	9	15.5	-	-
63	75	60	90	110	55.5	31	1	23.5	6	8.5	15.5	-	-
80	100	85	115	142	65.5	37	2	26.5	5	9.5	17	-	-

Frame Size	SA	SB	SC	SD	SE	SF	ST	SG	M	ST	SU	LT
35	64	-	14	20	78	36	4.5	21.6	8	3.5	M3	M3× 5, φ3.5× 11.5
42	74	-	19	25	88	41	5.5	25.8	12	3.5	M3	M3× 6, φ3.5× 12
50	84	25.5	21	30	95	-	5.5	28.3	12	3.5	M3 X 6	M3× 6, φ3.5× 13.5
63	102	33.5	29	38	115	-	6.5	34.3	12	4.5	M3 X 6	M4× 7, φ4.5× 15.5
80	132	40.5	36	45	147	-	8.8	42.9	12	5.5	M3 X 6	M5× 8, φ5.5× 20.5

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SRH Series – WPU-SRH-BD