Rexroth fixed displacement hydraulic motor for Bomag Road equipment 5801054 05802581 05802582 05802504 05802505 05802585 5800957

A fixed displacement hydraulic motor converts a constant volume of hydraulic fluid per revolution into rotational mechanical energy. Unlike a variable displacement motor, which can change its internal geometry to alter torque and speed output, a fixed displacement unit has one set displacement — meaning its output speed is directly proportional to the flow rate coming from the pump, and its torque is directly proportional to system pressure.

That simplicity is exactly why it's so popular in compaction equipment. Rollers don't need infinitely variable gearing logic on the drum or wheel drive — they need predictable, repeatable torque delivery that holds up under constant vibration loads, shock, and dirty jobsite conditions. Fewer moving control elements also means fewer failure points.

Why Bomag Pairs Rexroth Motors With Its Rollers

Bomag doesn't manufacture its own hydraulic motors — it specifies and integrates components from established hydraulics suppliers, and Rexroth has long been a primary partner for travel and vibration drive systems. A few reasons this pairing has stuck:

1. Durability Under Constant Vibration Loads

Compaction machinery vibrates almost continuously during operation. A hydraulic motor bolted to a drum eccentric shaft assembly is absorbing that vibration directly. Rexroth's fixed displacement motors use hardened, spherically-supported piston and cylinder assemblies that self-align as the shaft rotates, reducing cross-loading on internal components — a design detail that matters enormously in a vibratory environment.

2. High Power Density in a Compact Package

Roller chassis are tight. There's no room to oversize a motor just for the sake of a safety margin. Rexroth's compact bent-axis and radial piston geometries deliver high torque relative to their physical footprint, which lets Bomag keep drum and wheel assemblies as small and low-slung as possible — important for machine stability and center-of-gravity control on grades.

3. Consistent Performance in Harsh Environments

Asphalt and soil compaction sites are dusty, hot, and abrasive. Contaminated hydraulic fluid is one of the leading causes of premature motor wear industry-wide. Rexroth motors are engineered with tight but serviceable tolerances and robust seal packages designed to tolerate the contamination levels typical of construction sites — not laboratory-clean industrial settings.

4. Interchangeability and Parts Support

Because Rexroth motors are used across so much of the compaction equipment industry (not just Bomag, but Hamm, Dynapac, and others), parts availability, rebuild kits, and cross-reference data are well established. That matters when a roller is down, and a paving schedule is on the line.

Signs a Rexroth Motor on Your Bomag Roller Needs Attention

Field techs typically flag a few recurring symptoms:

Loss of torque under load — the roller stalls or slows noticeably on grades or in stiff material, often pointing to internal leakage past worn pistons or the control unit.

Erratic or surging travel speed — can indicate air ingestion, a failing case drain seal, or contamination-related wear in the valve plate/control unit.

Excessive case drain flow or overheating — a strong signal of internal wear increasing bypass leakage.

Unusual noise or vibration beyond normal drum operation — can indicate bearing wear or cavitation from a restricted supply line.

Visible fluid at shaft seals — often a symptom of excess case pressure rather than a simple seal failure, so the root cause needs to be checked before just swapping the seal.

Maintenance Best Practices

Keep Fluid Clean and Cool

Since these motors operate to tight internal tolerances, contamination control is the single highest-leverage maintenance action. ISO cleanliness targets specified by Rexroth should be treated as a real requirement, not a suggestion — most premature motor failures trace back to particulate contamination or water intrusion.

Monitor Case Drain Flow

Case drain flow is one of the best early-warning indicators of internal wear. A gradual increase in case drain flow over time, measured against baseline, often shows a motor beginning to wear internally well before a hard failure occurs.

Don't Ignore Cold-Start Behavior

Hydraulic fluid viscosity at startup in cold weather affects motor lubrication and can accelerate wear if the machine is put under full load before the system reaches operating temperature. Following Bomag's specified warm-up procedure protects the motor as much as the pump.

Use Genuine or Rexroth-Certified Rebuild Kits

Because these motors run to precise internal clearances, using OEM-spec seal kits, pistons, and valve plates during a rebuild — rather than generic aftermarket substitutes — preserves the performance and lifespan the motor was designed for.

For more brand and equipment models, please visit https://www.baolilaihydraulic.com/brand/

Q1: How long should a Rexroth fixed displacement motor last on a roller?

A1: With clean fluid, proper maintenance, and normal duty cycles, these motors commonly run several thousand hours before needing an internal rebuild. Actual life varies significantly based on contamination control, load cycles, and operating environment.

Q2: What's the most common cause of premature motor failure on these machines?

A2: Fluid contamination — particulate or moisture — is the leading cause across the industry, followed by operating the machine under load before adequate warm-up in cold conditions.

Q3:What is the price and delivery time of the Rexroth fixed displacement motor for the Bomag Road equipment？

A3: The specific price and delivery time will depend on the equipment model or specific product model you provide.

Q4:How to purchase a Rexroth fixed displacement motor for the Bomag Road equipment?

A4:You can visit https://www.baolilaihydraulic.com/contact/ to contact us and purchase our products through various methods.