BM hydraulic motor (orbital motor) showing the ports, square flange and splined output shaft

01Ports

02Mounting flange

03Output shaft

Typical BM configuration shown. Flange, output shaft and ports are selected by order code.

Hydraulic motor · Mainly custom-built

BM Series
Orbital Hydraulic Motor

The BM hydraulic motor is a gerotor (orbital) motor: small, compact, with low starting pressure and easy reversing; motors can be connected in series or in parallel in the hydraulic system. BM1 and BM2 have shaft-valve distribution; BM5 and BM6 have disc-valve distribution with pressure compensation and can take higher radial loads. Flanges, output shafts and ports come in many combinations and can be customized to the machine. Need more torque? See JST radial piston motors: JHM Series and JNM Series.

Submit a custom request View catalog models

Catalog models: 30models · 4 series
Rated / continuous torque: 78–1,685N·m
Displacement: 50–985ml/r

Technical data

BM Series model data

Use the selection map to locate models by the torque and speed you need, then see the full data for that series in the table below; outline dimensions and order codes are in each series' drawings.

Selection map

Each dot is one catalog model

Required continuous torque N·m Speed (min.) r/min

Showing all 30 models

Horizontal axis: rated (BM1, BM2) or continuous (BM5, BM6) torque, N·m, log scale. Do not run at maximum speed and maximum pressure at the same time.

Click any model on the map to see its data, or enter the torque you need.

Series

Unit

Search model, displacement or torque

BM Series orbital hydraulic motor model data
Model	Displacement (ml/r)	Rated / continuous torque (N·m)	Pressure (MPa)	Speed (r/min)	Approx. weight (kg)
BM17 models · 50–200 ml/r · 78–280 N·m · pressure and speed rated / max.
BM1-50	50	78	12.4 / 13.8	870 / 1020	5.1
BM1-63	63	99	12.4 / 13.8	692 / 816	5.4
BM1-80	80	126	12.4 / 13.8	684 / 824	5.6
BM1-100	100	158	12.4 / 13.8	547 / 659	6.2
BM1-125	125	197	12.4 / 13.8	475 / 560	6.5
BM1-160	160	234	11.5 / 12.4	353 / 364	6.7
BM1-200	200	280	11 / 12.4	276 / 290	6.9
BM27 models · 80–400 ml/r · 150–435 N·m · pressure and speed rated / max.
BM2-80	80	150	13.8 / 15.5	600 / 650	10
BM2-100	100	189	13.8 / 15.5	480 / 520	10.5
BM2-160	160	259	12.4 / 13.8	305 / 330	11
BM2-200	200	315	12.4 / 13.8	240 / 270	11.2
BM2-250	250	385	12.4 / 13.8	185 / 210	11.6
BM2-315	315	408	10.3 / 12.4	151 / 180	12
BM2-400	400	435	9 / 10.3	128 / 140	12.5
BM58 models · 80–400 ml/r · 235–781 N·m · pressure and speed continuous / intermittent
BM5-80	80	235	20.5 / 31	799 / 908	18
BM5-100	100	295	20.5 / 31	742 / 924	18.5
BM5-125	125	385	20.5 / 31	576 / 720	19
BM5-160	160	455	20.5 / 26	477 / 713	19.5
BM5-200	200	540	20.5 / 26	385 / 577	20.4
BM5-250	250	660	20.5 / 26	308 / 462	20.5
BM5-315	315	781	20.5 / 24	226 / 346	21
BM5-400	400	775	15.5 / 24	191 / 335	22
BM68 models · 195–985 ml/r · 575–1,685 N·m · pressure and speed continuous / intermittent
BM6-195	195	575	17 / 27.5	775 / 866	28.1
BM6-245	245	735	17 / 27.5	615 / 834	28.6
BM6-310	310	930	17 / 27.5	485 / 689	29.2
BM6-395	395	1155	17 / 27.5	387 / 570	30
BM6-490	490	1445	17 / 24.0	307 / 454	30.9
BM6-625	625	1380	15 / 17.0	241 / 355	32.1
BM6-800	800	1370	15 / 17.0	188 / 282	32.5
BM6-985	985	1685	17 / 17.0	153 / 230	33.5

Showing 7 of 30 models

Click a model to see its full data.

Ratings: the pressure and speed columns are “rated / max.” (BM1, BM2) or “continuous / intermittent” (BM5, BM6; speed is “max. continuous / intermittent”); torque in the table is the rated or continuous value. Maximum (intermittent) operating conditions are permitted for no more than 6 seconds; for BM5 and BM6, peak operation for no more than 0.6 seconds. Do not run at maximum speed and maximum pressure at the same time. “—” = not listed; please ask us if you need this value.

BM1

Shaft-valve · compact

Small, light and compact; wide speed range with no gearbox needed; many flange, output shaft and port connection options.

Displacement: 50–200 ml/r
Rated torque: 78–280 N·m
Approx. weight: 5.1–6.9 kg

BM2

Shaft-valve · inset-tooth gerotor set

Smooth running and long service life; suited to drives on injection moulding machines, small vehicles and similar machinery.

Displacement: 80–400 ml/r
Rated torque: 150–435 N·m
Approx. weight: 10–12.5 kg

BM5

Disc-valve · pressure compensated

Roller gerotor set with low starting pressure and smooth low-speed running; tapered roller bearings take higher radial loads. Available as standard motor, wheel motor and bearingless motor.

Displacement: 80–400 ml/r
Continuous torque: 235–781 N·m
Approx. weight: 18–22 kg

BM6

Disc-valve · twin bearings

Twin-bearing support takes higher radial forces; the flange is integral with the housing to withstand frequent reversing shocks; high output torque.

Displacement: 195–985 ml/r
Continuous torque: 575–1,685 N·m
Approx. weight: 28.1–33.5 kg

Operating requirements

Correct use for a longer motor life

The notes below apply to all series; specific values depend on the selected model and the approved drawing.

Operating limits

Do not run at maximum speed and maximum pressure at the same time
Maximum (intermittent) conditions for no more than 6 seconds
BM5, BM6 peak operation for no more than 0.6 seconds

Oil & running-in

Anti-wear hydraulic oil, viscosity 37–73 cSt, cleanliness ISO 18/13
Maximum operating oil temperature 80 ℃
Before full-load operation, run in at 30% of rated pressure for at least 1 hour

Back pressure & external drain

Maximum permissible back pressure up to 7 MPa; 3.5 MPa or less recommended
Above this, connect an external drain line and keep the motor filled with oil
Restrict the drain line to keep a back pressure above 0.35 MPa

Custom builds

Mainly custom-built, designed around your machine

The catalog models are a starting point for selection. Each item below can be designed to the torque, speed and mounting conditions of your equipment.

Series & displacement

Four series, BM1–BM6, 50–985 ml/r
Torque and speed matched to system pressure and flow
Standard motor, wheel motor, bearingless motor (BM5)

Flange & output shaft

Square, diamond, rectangular, large / small square flanges
Parallel keyed shaft, straight spline, involute spline, tapered shaft
Inch shaft diameters and pilots

Ports & drain

Metric or G-thread ports, or manifold mounting
External drain port optional
Manual directional valve (some BM5 models)

The four BM series compared

Item	BM1	BM2	BM5	BM6
Distribution	Shaft-valve	Shaft-valve	Disc-valve, pressure compensated	Disc-valve, pressure compensated
Catalog models	7	7	8	8
Displacement	50–200 ml/r	80–400 ml/r	80–400 ml/r	195–985 ml/r
Torque	Rated 78–280 N·m	Rated 150–435 N·m	Continuous 235–781 N·m	Continuous 575–1,685 N·m
Pressure	Rated 11–12.4 / max. 12.4–13.8 MPa	Rated 9–13.8 / max. 10.3–15.5 MPa	Continuous 15.5–20.5 / intermittent 24–31 MPa	Continuous 15–17 / intermittent 17–27.5 MPa
Approx. weight	5.1–6.9 kg	10–12.5 kg	18–22 kg	28.1–33.5 kg

For more torque, consider low-speed high-torque motors: JHM Series · JNM Series · QJM Series.

Selection support

Tell us your duty,
we'll confirm the right motor configuration.

Send the information in the checklist and we will check it against the catalog models or assess a custom design. The product catalog and installation drawing are provided once the model and mounting interface are confirmed.

Request selection support Find the right model Request the catalog Request an installation drawing

Please include

01Required output torque (continuous and intermittent) and speed
02System pressure, flow and back pressure; whether an external drain line is fitted
03Flange type, pilot and output shaft
04Port size and orientation, or your current motor's order code

BM Series
Orbital Hydraulic Motor