BM1 Series Gerotor Hydraulic Motor

Shijiazhuang Laiye Import& Export Trading Co., Ltd. is one of the leading manufacturers and suppliers of bm1 series gerotor hydraulic motor in China, also supports customized service. If you're going to wholesale high quality bm1 series gerotor hydraulic motor made in China, welcome to get pricelist from our factory.

Gerotor motors are different from pumps
If you are familiar with our gear pumps, they are designed to push fluid out. The BM1 Series Gerotor Hydraulic Motor does the opposite-it takes pressurized hydraulic oil in and turns it into rotating mechanical force. Inside the housing, there is a gerotor set consisting of an inner rotor and an outer stator. Pressurized oil enters the distribution system, pushes against the rotor lobes, and causes the output shaft to turn. This is a very simple and robust design, which is why these motors are often used in agricultural machinery and industrial equipment where reliability matters more than high speeds.

The spool valve distribution system
The internal distribution system uses a spool valve design. This is different from some other motors that use a disc valve. The spool valve arrangement allows for a smooth transition of oil between the inlet and outlet ports, which keeps the rotation steady even at lower speeds. The motor also includes a special distribution flow system that reduces noise during operation. If you are designing a machine where low noise is a factor-such as a grain auger or a conveyor on a public worksite-this feature supports a quieter operating environment.

Compact size and versatile mounting
The BM1 series is compact, but don't let the size fool you. Despite the displacement range (from 50 mL/r up to 400 mL/r), the body size does not scale up dramatically. It fits easily into tight spaces behind hydraulic valve blocks or under machine covers. We offer a variety of flange types, output shafts, and oil port connections to match different mounting configurations.

Displacement choices and speed range
The displacement ranges from 50 mL/r to 400 mL/r. Smaller displacements like the 50 mL/r run faster (698 r/min continuous) but produce lower torque (74 N·m). Larger displacements like the 400 mL/r run slower (145 r/min continuous) but generate much higher turning force (456 N·m). This range makes the series suitable for both slower rotary drives and medium-speed conveyor applications.

Continuous vs. intermittent pressure ratings
The motor is rated for a maximum continuous working pressure of 12.5 MPa, with an intermittent peak of 14 MPa. Intermittent pressure, as defined in the technical notes, refers to the maximum pressure at the entry port, while continuous working pressure refers to the pressure drop across the motor. There is a specific instruction to remember: You should not run the motor at both the highest pressure and highest speed at the same time. Doing so overstresses the internal bearings and gerotor set. In the field, we generally recommend running at a lower pressure when high speeds are required, and reducing the speed when operating at peak pressure.

Torque output and efficiency
The BM1 series delivers a continuous torque range from 74 N·m (on the 50 mL/r model) up to 456 N·m (on the 400 mL/r model). The intermittent torque goes slightly higher. The design also maintains a good overall efficiency level for medium-duty applications. For applications like auger drives or sweeper brushes where you need consistent power over long shifts, this torque curve provides a good balance of power and durability.

Reliable shaft seal design
A common failure point in hydraulic motors is the shaft seal, especially when back-pressure builds up in the return line. The BM1 series uses a credible shaft seal design that can withstand high back-pressure. It can also be plumbed in series with other motors if required. However, a note from the specifications is worth highlighting: The maximum allowable back-pressure on the return side is 10 MPa, but it is recommended to keep it below 5 MPa. If the return pressure exceeds 5 MPa, we recommend using a separate drain line (external leak line) to relieve pressure behind the shaft seal.

Operating Environment & Notes:

Working Temp.: Max 80°C.

Volumetric Efficiency: High for medium-duty applications.

Caution: The motor should not operate at both the highest pressure and highest speed simultaneously. When running intermittently, the running time should not exceed 10% of the total cycle.

Agricultural conveyors and augers
When you see a grain auger working on a farm, the unit driving the rotating screw is often a BM1 Series Gerotor Hydraulic Motor. It is used frequently on farm equipment to drive grain augers and conveyor belts. The motor's ability to run steadily at low speeds (like the 100 mL/r model at 560 r/min) provides consistent torque to move grain up a steep incline without stalling. The low noise operation is also beneficial in enclosed sheds or processing facilities.

Industrial sweeper brushes
In industrial floor sweepers, the motor drives the main sweeping brush. The motor operates for long hours, often with varying loads as the brush picks up debris. The reliable shaft seal design is important here to avoid oil leaks onto the cleaning surface.

Plastic and rubber processing machinery
For slow-turning rollers and winders, the larger displacement motors (250 to 400 mL/r) provide the high torque needed to wind and guide heavy material. The ability to operate in series (plumbing multiple motors off the same flow source) is sometimes used in these setups to synchronize multiple rollers.

Our approach to production
We have been manufacturing hydraulic components for mobile machinery since 1988. The BM1 series is produced in a facility equipped with precision machining centers for the motor housings and specialized equipment for the gerotor set manufacturing.

What we check before assembly
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 BM1 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.

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