BM4 Shaft Distribution Orbital Hydraulic Motor 245-800 Cc/rev

BM4 Orbital Hydraulic Motor Overview

Six displacements, one 123 mm body: the BM4 orbital hydraulic motor covers 245, 310, 390, 490, 630 and 800 cc/rev. It is a shaft distribution hydraulic motor with an integrated output shaft, a geroler roller set and rolling bearings at both ends.

Catalogue applications include oilfield machinery, coal machinery and small cranes. Fit on a specific machine is confirmed against your model, the existing motor part number, its drawing and your duty cycle.

Model Designations and Local Terms

• Hyphen and space variants: BM4-245 / BM4 245, BM4-310 / BM4 310, BM4-390 / BM4 390, BM4-490 / BM4 490, BM4-630 / BM4 630, BM4-800 / BM4 800.
• Spanish: motor hidráulico orbital BM4, motor orbital con distribución por eje.
• French: moteur hydraulique orbital BM4, moteur orbital à distribution par l'arbre.
• Russian: орбитальный гидромотор BM4, гидромотор с распределением через вал.

Key Features of the Shaft Distribution Motor

• Shaft distribution: Oil is distributed through the integrated output shaft. This is neither a disc-valve motor nor a piston motor.
• Geroler roller set: The catalogue specifies a roller-type rotor and stator set.
• Rolling bearings at both ends: The output shaft is supported front and rear. Check the bearing load on side-loaded drives such as sprockets or winch drums.
• Common 123 mm body: Catalogue dimension H1 runs from 27 mm to 89 mm; check the complete installation drawing for each configuration.
• Rectangular spline motor options: The catalogue lists five rectangular-spline and four keyed-shaft codes; coupling dimensions and the A9 discrepancy require confirmation.
• Four mounting codes: Two square flanges (F1, F2) and two plate mounts (F3, F4) are available, with pilots of 100 mm or 125 mm.
• Finish options: N unpainted, Q blue, B black, S silver.

Technical Specifications and BM4 Model Selection

Flow is rated at 80 L/min continuous and 100 L/min intermittent for all six sizes. Choose the displacement from the torque you need, then check the speed limit at that displacement.

Read the limits separately. Each figure is an individual maximum, not a simultaneous operating point. Intermittent duty must be confirmed against your actual duty cycle.

Mounting, Port, Shaft and Rotation Codes

Equipment Matching Checklist

1. Machine model and the part number on the existing motor's nameplate.
2. Motor drawing or photos showing the flange, shaft end and port face.
3. Flange size, bolt pattern and pilot diameter, measured in mm.
4. Shaft type, spline count and dimensions, or keyed diameter and key size.
5. Port type, thread size and whether an external drain line is used.
6. Required rotation, plus the working pressure, speed, torque and duty cycle.

Part Numbers, Search Names and BM4 Applications

Olive Branch Hydraulics supplies this BM4 shaft-distribution series for the catalogue application groups of oilfield machinery, coal machinery and small cranes. No particular machine brand, model or lifting function is established by the series name alone.

Common enquiry descriptions include BM4 cycloidal hydraulic motor, low-speed high-torque orbital motor, radial-bearing shaft-distribution motor, rectangular-spline hydraulic motor and keyed-shaft BM4 motor. A space or hyphen variation identifies a nominal model, not a complete configured motor.

For part-number enquiries, send the full original motor number, nameplate and equipment model. The catalogue provides BM4 plus displacement, flange, shaft, port, rotation and paint fields; no external numeric OEM code is presented as an Olive Branch SKU or a verified direct replacement.

The product photo is a BM4 series structure reference showing a four-bolt square flange, rectangular spline and straight side ports. It does not establish a specific displacement or every optional interface; dimensions and ratings follow the Olive Branch catalogue drawings supplied below.

See the adjacent BM3 shaft-distribution motor for separate series data. Confirm dimensions and ratings before comparing replacements.

Ordering from Olive Branch Hydraulics

Every order is built to a configuration matched against a drawing that you have confirmed. The full code, covering displacement, flange, ports, shaft, rotation and paint, is fixed before production, so repeat orders reproduce the same motor.

• Wholesale and distributors: We quote per configuration code at EXW Hebei, with a separate price for each order quantity you specify.
• OEM/ODM: Submit requirements for drawing review. Sample terms, any approved sample, batch specification and delivery schedule are agreed on the quotation.
• Private label: We supply white-label or custom packaging and labels that carry your brand and part number.
• Project buyers and end users: We verify duty and dimensions before quoting. Replacement units are ordered by the same confirmed code.
• Regional agents: Territory and pricing terms are agreed individually on application.

BM4 Orbital Motor FAQ

Is the BM4-490 the same as a BM4-500?

No. We supply 490 cc/rev nominal; if your machine specifies 500, send the drawing and duty so we can review it.

Can I run at maximum pressure and maximum speed together?

Not by default. Each rated limit applies on its own, and intermittent operation must be confirmed against your duty cycle.

Which shaft is A9?

That is decided by the drawing only. Our drawing shows Ø30 mm with an A8x7x28 key, while the ordering table lists Ø40 mm, so we confirm against your sample or drawing before quoting.

Will it replace the motor on my drilling rig, coal equipment or crane?

Only after verification. Fit requires the installed motor part number, equipment model, dimensions and duty point; the six-point checklist above sets out the required information.

Are P2 and P3 port plates interchangeable?

No. Both use 2x M18x1.5 main ports with an M14x1.5 drain, but the port face geometries are different.

How are prices and terms quoted?

Prices are EXW Hebei, per configuration code. MOQ, sample charges and lead time are stated on each quotation.

Request a BM4 Motor Quote

Send the existing motor part number or drawing, your flange, shaft and port codes, and two or three order quantities. We will return an EXW Hebei price for each quantity tier, plus a configuration drawing for your sign-off.