BM2 Series Gerotor Hydraulic Motor

Shijiazhuang Laiye Import& Export Trading Co., Ltd. is one of the leading manufacturers and suppliers of bm2 series gerotor hydraulic motor in China, also supports customized service. If you're going to wholesale high quality bm2 series gerotor hydraulic motor made in China, welcome to get pricelist from our factory.

Moving past the BM1 limits
When we built the BM1 series, we intentionally kept the pressure ceiling at 12.5 MPa. It fits 90% of the medium-duty applications out there. But every so often, we run into customers with a round baler or a heavy-duty conveyor who need just a little more pushing force without having to step up to a much larger, bulkier motor. That's exactly what led to the BM2 series. We took the same compact footprint and redesigned the internal gerotor geometry so it can handle 14 MPa continuously and peak at 17 MPa. The result is noticeably higher torque without changing the mounting envelope.

What the 500 mL/r model offers
The largest motor in the series reaches 500 mL/r displacement. We added this size for applications like grain augers and winches where the rotation speed is relatively low-down to about 110 r/min-but the torque requirement is high. On the 500 model, the continuous torque is 464 N·m, which is enough to turn a heavy screw conveyor without bogging down when the material gets dense.

How the internal distribution works
Inside the motor, you have a spool valve that directs pressurized oil into the gerotor set. In the BM2, we refined the valve geometry to improve fluid distribution. What you notice in practice is that the motor runs smoother at lower speeds. If you operate a sweeper brush or a harvesting header, you don't want the drive to jerk or surge when it first starts turning. This design helps prevent that.

Flange options and why they matter
One of the practical challenges when you are retrofitting a motor on an older machine is getting the mounting holes to line up. The BM2 series solves this by offering 5 distinct flange patterns: a 4-square flange, 2-rhombus, 4-rectangular, 4-rhombus, and 6-rhombus. Some of these patterns are common on European tractors; others are standard on North American farm equipment. Instead of machining a custom adapter plate, you can simply order the motor with the flange that already matches your bracket.

Pressure ratings at different sizes
You will notice that the maximum continuous pressure drops as the displacement gets larger. The 50 to 160 mL/r motors are all rated for 14 MPa continuous. As you go up to the 200 and 250 models, the rating drops to 12.5 and 11 MPa. The 400 and 500 models are rated at 9 and 8 MPa.

This isn't a manufacturing limitation. It is a deliberate design choice to protect the larger gerotor set from overloading the internal bearings and the drive shaft. If you are running a 500 mL/r motor at 14 MPa, the torque generated would exceed the shaft's safe bending limit. The lower pressure rating keeps the motor within its safe mechanical operating window.

Axial and radial shaft loads
There is a limit to how much side-load the output shaft can handle. We specify a maximum radial load of 400 Kg and a maximum axial load of 200 Kg. If you are mounting a chain sprocket directly on the shaft, the chain tension creates a bending force. If that force exceeds the 400 Kg limit, it will put stress on the internal bearings and cause premature failure. For applications like that, an external bearing support is usually the better solution.

Rotation direction
The standard rotation is clockwise when the A port is pressurized, viewed from the shaft end. If your machine requires counter-clockwise rotation, you simply pressurize the B port. It is a fully reversible motor.

Round balers and combines in the field
When you install a hydraulic motor on a large round baler or combine, it's running almost constantly during harvest. The drive speed is moderate, but the load can fluctuate quickly as the machine picks up heavy swaths of crop. One thing we've noticed in the field is that if the motor begins to feel unusually hot to the touch, or if it starts making a rhythmic knocking sound, the case drain is usually the first place to check. If the drain line is pinched or not connected directly back to the tank, the pressure behind the shaft seal builds up. That pressure increases internal drag and raises the temperature. We've found that running a dedicated drain line straight to the tank prevents this issue on almost every machine.

Conveyors in recycling and processing plants
In an industrial setting, a conveyor drive sees steady, heavy loads all day. The motor has to be able to start under a full belt load without stalling, because once the belt stops, the material on top of it becomes a dead weight. The higher continuous pressure rating of the BM2 series helps avoid stalling at startup. Another practical point we see regularly on these jobsites is the need to replace an old motor on a bracket that was welded into place years ago. The variety of flange patterns in the BM2 series often allows a direct bolt-on replacement without needing to modify the bracket or weld a new plate.

Auger drives on mini-excavators
Mini-excavators and small drills have very limited space around the hydraulic motor. The BM2 series is compact enough to fit in those tight cavities, which eliminates the need to design a complex mounting bracket around the motor. When the machine is drilling into hard clay or compacted soil, the torque needs to come in steadily without surges. The internal spool valve design in this series keeps the rotation smooth even when the drill bit hits denser material. Operators tend to notice that difference quickly during the first few minutes of use.

 

Production background
We have been manufacturing hydraulic components for mobile machinery since 1988. The BM2 series is produced in a facility equipped with precision machining centers for the motor housings and specialized equipment for the gerotor set manufacturing.

Pre-assembly inspection
The gerotor set is the heart of the motor. The inner rotor and outer stator are inspected carefully for dimensional accuracy. The clearance between these two parts determines the motor's volumetric efficiency. The spool valve components are also inspected for smooth movement before assembly. The cast iron bodies are checked for cracks or porosity.

Final testing
Every BM2 motor is tested on a hydraulic test bench before shipping. We run it at the rated speed and pressure to verify the torque output and efficiency. We also check for leaks at the shaft seal and the port faces. Any motor that shows abnormal noise, vibration, or leakage during testing is set aside for rework.

Customization
We can provide the motor with various flange types, output shafts, and port orientations based on OEM requirements. If you need a version that is not listed in the standard table, please contact our engineering team to discuss feasibility.

Hot Tags: bm2 series gerotor hydraulic motor, China bm2 series gerotor hydraulic motor, manufacturers, suppliers, factory, dc valve in hydraulic, directional spool valve, hydraulic directional, hydraulic pilot operated directional control valve, pilot operated directional control valve, solenoid controlled hydraulic valves