Radial Plunger High-pressure Hydraulic Five-star Motor for Forging

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Radial Plunger High-pressure Hydraulic Five-star Motor for Forging

Strong high-pressure power: Specifically designed for high-pressure hydraulic systems, with a rated working pressure of up to 25-35 MPa or even higher, it can provide outstanding output torque and powerful driving force, meeting the requirements of heavy-duty applications.
Low speed with large torque, smooth operation: The core radial piston and five-star wheel (eccentric crankshaft) structure inherently possesses excellent low-speed stability and high starting torque, enabling smooth driving of large inertia loads at low rotational speeds, with a wide speed regulation range.
Sturdy structure, long-lasting durability: Utilizing heavy-duty bearings and reinforced housing design, the key friction pairs have high wear resistance, capable of withstanding continuous impacts and vibrations, ensuring high reliability and extremely long service life in harsh industrial environments.
Compact and efficient, direct drive: The radial structure is relatively compact and has high power density. It can directly install the driving load, eliminating or simplifying external reduction mechanisms, saving space, achieving efficient transmission, and having a small backlash.
Broad compatibility, flexible application: Offers multiple installation methods, shaft extension options and control interfaces, enabling easy integration into various systems such as construction machinery, mining equipment, ship deck machinery, and heavy turntables that require reliable rotational power.

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NHM
Brand:
MDP Hydraulics

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Product Description

The radial piston high-pressure five-star hydraulic motor for forging (commonly known as the "five-star motor" or crankshaft-rod type radial motor) is a low-speed, high-torque, high-pressure, and highly shock-resistant hydraulic rotating actuating element specifically designed for extreme conditions in the forging industry. It directly addresses the continuous intense impact loads, high-temperature radiation, heavy-load start-stop, and high-pollution environment challenges faced by forging equipment (such as forging machines, rotary tables, hydraulic forging hammers, and rolling machines). By strengthening the internal structure, optimizing materials and seals, it efficiently and reliably converts hydraulic energy into powerful rotational torque. This motor, with its outstanding starting performance, excellent low-speed stability, extremely high overload capacity, and long-lasting durability, has become the core power heart of modern automated forging production lines, enabling precise rotation, clamping flipping, and feed drive of workpieces.

Working Principle and Core Structure

This product is a radial piston hydraulic motor, and its core adopts the classic five-piston eccentric crankshaft (five-star wheel) connecting rod mechanism.

• Working principle:

Pressurized oil enters the piston cylinders arranged radially in the shape of a five-star through the distribution shaft (or distribution disc) in an orderly manner. High-pressure oil drives the pistons to move outward, and the pistons transfer the force through the connecting rods (or directly through the rollers) to the eccentric wheel of the eccentric crankshaft, generating a tangential force that drives the crankshaft to rotate. Multiple pistons work continuously and alternately around the circumference of the crankshaft, forming a smooth and continuous rotational torque output. Changing the direction of oil inlet and outlet can achieve the forward and reverse rotation of the motor.

• Core development of adaptive structure:

Strengthening the crankshaft and heavy-duty bearings: The crankshaft is forged from high-strength alloy steel and undergoes special heat treatment and surface hardening to withstand extremely large alternating bending and torsional loads. The supports use large-sized tapered roller bearings or special needle bearings, which can simultaneously withstand extremely high radial forces, axial forces, and overturning moments. This is crucial for resisting the forging impact.
High-pressure shock-resistant piston assembly: The piston and cylinder bore are paired with wear-resistant materials, and the mating clearance is optimized. Even under high pressure, it can maintain high volumetric efficiency. Between the connecting rod and the crankshaft eccentric wheel, usually, roller or hydrostatic bearings are used to convert sliding friction into rolling friction, reducing wear and improving mechanical efficiency and lifespan under impact loads.
High-temperature and high-pressure sealing and flow distribution: Utilize fluororubber (FKM) and other high-temperature-resistant sealing components to withstand the high environmental temperatures in the forging workshop. The flow distribution components (flow distribution shaft and valve sleeve) are made of wear-resistant materials and may be designed with pressure balance grooves to ensure reliable sealing and rapid response under high pressure and temperature fluctuations.

Key Design Features and Advantages

Ultra-low speed and high torque with high startup efficiency:

Naturally possesses high starting torque (with a startup mechanical efficiency of over 0.90), capable of smoothly outputting full torque at extremely low speeds (even below 1 rpm), directly driving heavy forging pieces for precise angle adjustments or slow rolling, without the need for a gearbox, thus avoiding transmission gaps.
The speed adjustment range is extremely wide, meeting the full range of speed requirements in forging processes, from precise alignment to rapid return.

Outstanding high-pressure and shock resistance capabilities:

Specifically designed for high-pressure systems, the rated working pressure typically ranges from 25 to 35 MPa, and the peak pressure is even higher, enabling the provision of significant output torque.
The robust mechanical structure and heavy-duty bearings enable it to withstand the intense and intermittent impact loads generated during the forging process without any internal damage or performance degradation.

High-temperature operating conditions and environmental adaptability:

The sealing system, shell coating, and lubricating oil selection all took into account the high-temperature environment of the forging workshop. The design of the oil drain pipeline ensures that heat can be effectively removed even under heat radiation, preventing the internal components from overheating.
The housing has a high level of protection (such as IP65), which can prevent the intrusion of oxide scale, dust and water vapor.

High reliability and extremely long service life:

All critical friction components have been specially designed and treated for heavy-duty and impact conditions to ensure durability.
The low-speed operation characteristic itself reduces the relative movement speed and cycle count of the components, thereby theoretically prolonging the service life.
The maintenance interval is long. With correct usage and maintenance, it can withstand the tests of several years of intense forging operations.

Direct drive, compact structure:

Can be directly connected to the worktable, gears or chain drive mechanisms, eliminating the need for a large reduction mechanism, simplifying the equipment design, saving space, and enhancing the system's rigidity and response speed.

Typical application scenarios of forging

• Forging operation machine: It drives the clamps to achieve precise rotation, inclination and movement of the forging piece, and is the core executive component of automated forging.

Rotary table / Forging machine: Drives the heavy worktable for indexing and positioning, facilitating multi-directional hammering or model changing.

• Hydraulic forging hammer / press auxiliary mechanism: Drives the feeding trolley, rotates the mold or rotates the workpiece.

Hub expansion machine: As the power source for the active drive roller, it provides smooth and powerful pressing torque.

• Bar shearing machine: Drives the feeding roller track to achieve precise feeding of heavy bars.

Selection, Installation and Maintenance Guidelines

• Key to selection:

1. Calculate torque requirements: Based on the maximum weight of the forging, the force arm, the friction coefficient, and the acceleration requirements, calculate the maximum working torque and peak torque.

2. Determine system pressure: Match the working pressure of the existing hydraulic system and calculate the required displacement.

3. Verify speed range: Confirm that the minimum and maximum speeds required by the process are within the allowable range of the motor.

4. Evaluate load characteristics: Determine the amplitude and frequency of the impact load, and select the model with sufficient bearings and structural reinforcement grades.

5. Interface matching: Determine the installation method and output shaft connection form (which must be able to transfer the calculated torque) based on the equipment structure.

• Installation Key Points

1. Rigid Installation: The base plate for installation must have extremely high rigidity to prevent deformation under impact. Use high-strength bolts with the specified torque for tightening.

2. Precise Alignment: The output shaft and the load shaft must be strictly aligned. Even a slight deviation will be amplified under impact loads, causing damage to the bearings or shaft seals. It is recommended to use a bevel gear coupling.

3. Oil Drainage Pipeline: The drain port (L port) of the housing must be independently, unobstructed, and without back pressure connected back to the oil tank. This is the lifeline for protecting the shaft seal.

4. Oil Fluid and Filtration: High-quality, high-viscosity-index anti-wear hydraulic oil must be used, and ensure the ultra-high cleanliness of the oil (recommend NAS 7-8 grade). Install a high-pressure filter in the oil inlet line.

• Operation and Maintenance:

1. Warm-up operation: The initial run should be conducted under low load for the purpose of warm-up.

2. Condition monitoring: Regularly check for any abnormal noises, vibrations, overheating, or leaks during the motor operation.

3. Regular maintenance: Replace the hydraulic oil and filter elements as per the schedule, and regularly inspect the bolt tightening status and the seal condition.

4. Professional inspection and repair: When there is a decline in performance or a malfunction, it should be disassembled and inspected by personnel with professional knowledge and tools. The repair and replacement of core components (such as the flow distributor and bearings) require precise adjustments.

Value Proposition

The radial piston high-pressure five-star hydraulic motor for forging is a professional solution specifically designed to meet the most demanding requirements of "industrial forging". Its value goes far beyond merely providing rotational power; it also brings unparalleled reliability, precise control, and durability in the face of extreme conditions to the forging process. By achieving direct drive with low speed and high torque, it simplifies the mechanical transmission chain, enhances system response and positioning accuracy. Its outstanding shock resistance and heat resistance design ensures stable output for several consecutive years at the core workstation, significantly reducing unplanned downtime due to power component failures, and directly ensuring the availability, production safety, and long-term economic benefits of the forging production line. Choosing it is choosing to lay a solid, reliable, and efficient power foundation for your forging equipment.

FAQ

I. Product Features and Selection

Q1: What are the core advantages of this five-star hydraulic motor? Why is it particularly suitable for forging applications?

A1: The core advantages lie in low-speed high-torque, high-starting efficiency, excellent shock resistance and extremely high reliability. The characteristics of forging operations include continuous heavy-load impacts, frequent starts and stops, and high-temperature environments. The radial piston and eccentric crankshaft structure of the Five-Star motor inherently possess excellent low-speed stability and high starting torque, enabling it to directly drive heavy forging pieces for precise rotation. Its reinforced crankshaft, heavy-duty bearings and high-temperature resistant sealing design allow it to withstand the intense impacts and heat radiation during the forging process, ensuring long-term stable operation.

Q2: How do I select the appropriate motor model for my forging equipment (such as the operating machine, rotary table)?

A2: The selection process requires precise load calculation:

1. Calculate torque: Based on the maximum weight of the forged piece, the force arm, friction coefficient, and acceleration requirements, calculate the maximum working torque and peak impact torque.

2. Determine pressure and displacement: Match the working pressure of your hydraulic system (usually 25-31.5 MPa). The required displacement (V, unit mL/r) can be estimated using the formula: V ≈ (T * 6.28) / (ΔP * η_m), where T is the required torque (N·m), ΔP is the pressure difference between the inlet and outlet oil (MPa), and η_m is the mechanical efficiency (can be 0.90-0.95).

3. Check speed: Confirm that the minimum stable speed required by the process (can be as low as 1-5 rpm) and the maximum speed are within the allowable range of the motor.

4. Evaluate bearing load: Forging impacts generate huge radial and axial forces, so ensure that the load of the selected model's bearings can meet the requirements.

Q3: What are the approximate rated pressure, displacement and torque range of the motor?

A3: Taking the common JMDG series as an example, its rated working pressure can reach 25-31.5 MPa, and the peak pressure can exceed 35 MPa. The displacement range is wide, ranging from several tens to several thousand milliliters per revolution (for example, the JMDG series ranges from 50 to 1000 mL/r and above), and the corresponding rated torque varies from several hundred to tens of thousands of newton-meters. Specific parameters need to be checked for the specific model. For forging applications, medium to large displacement models are usually selected.

Q4: How high can the motor withstand the ambient temperature? Can water glycol be used?

A4: The standard model is designed to operate within a working temperature range of -20°C to +80°C. The forging workshop has a high ambient temperature, so it is crucial to ensure adequate cooling of the housing and unobstructed oil drainage. If the hydraulic system uses non-flammable fluids such as water glycol (HFC) or phosphate esters (HFDR), it must be specified clearly at the time of ordering so that fluororubber (FKM) and other media-resistant seals can be equipped. Please note that using substitute oil may affect the expected lifespan and allowable pressure.

II. Installation and Startup

Q5: What are the most important things to keep in mind during installation?

A5: Correct installation is the guarantee of longevity. For forging applications, stricter requirements apply:

1. Rigid installation and precise alignment: The installation base must have extremely high rigidity to resist impact deformation. The concentricity of the motor output shaft and the load shaft (such as gears, sprockets) must be strictly ensured (typically requiring an out-of-centerness of less than 0.1mm), and it is strongly recommended to use flexible high-torque couplings such as drum-shaped tooth couplings. Poor alignment is the main cause of early damage to bearings, shaft seals, and broken shafts.

2. Drainage pipeline (critical!): The drain port (L port) of the housing must be directly and without back pressure connected to the oil tank using an independent and sufficiently large pipe. The highest point of the drainage pipe must be higher than the motor housing to prevent the housing from emptying. In forging conditions, it is strictly prohibited to install throttling valves or create back pressure on the drainage pipe; otherwise, the shaft seal will be quickly damaged.

3. Oil and filtration: High-quality anti-wear hydraulic oil must be used, with extremely high cleanliness requirements (recommendation: reaching NAS 7-9 grade or higher). A high-precision filter must be installed on the suction path.

Q6: What preparations need to be made before the first startup? A6:

1. Filling with oil: Before starting, the motor housing must be filled with clean hydraulic oil.

2. Pointing and exhausting air: Point the drive motor several times in the unloaded state to ensure that all the air is expelled from the system.

3. Low-pressure running-in: Run the system at low pressure (e.g. < 5 MPa), without load or with a light load for a period of time to perform running-in.

4. Gradual loading: Gradually increase the load to the normal working pressure, avoiding sudden and violent impacts.

III. Operation and Troubleshooting

Q7: The motor is running weakly and the rotational speed is decreasing. What could be the reasons?

A7: This is a common problem with forging equipment. A systematic investigation is required:

1. Hydraulic system issue: Check if the output pressure and flow of the main pump are sufficient, and verify if the relief valve settings are correct.

2. Excessive leakage in the motor: Long-term heavy-load impact may cause wear on the flow distributor plate and the end face of the cylinder body, an increase in the gap between the piston and the cylinder bore, or damage to the sealing ring, resulting in internal leakage of high-pressure oil. This is manifested as acceptable performance at cold start, but significant performance degradation when the oil temperature rises.

3. Poor oil suction or air intake: Check if the oil suction filter is clogged and if the oil suction pipeline is leaking.

4. Fault in the variable control mechanism (if it is a variable motor): Check if the control oil circuit is unobstructed and if the control valve is stuck.

Q8: If the motor produces abnormal noise and vibration, how should it be diagnosed?

A8: Abnormal noise is a precursor to a fault, especially under impact loads:

1. Cavitation sound (sharp cracking sound): The most typical manifestation of insufficient oil suction. Check the suction filter, piping, oil level, and oil viscosity (the viscosity may be too high during cold start).

2. Impact or friction sound:

Mechanical misalignment: Produces periodic dull knocking sounds and intense vibrations. The concentricity must be re-adjusted.
Internal component damage: If the bearings, connecting rods, rollers, or crankshaft eccentric wheels are worn out, there will be regular friction or impact sounds.
Double-headed key (transmission key) shearing or loosening: This may cause abnormal noises and intermittent rotation.

3. "Sloppy" or unstable performance: This occurs when air is mixed into the oil or when the system's oil supply is unstable.

Q9: What should be done if oil leaks from the motor housing or the shaft end? A9:

• Oil leakage at the shaft end: The most common cause is the wear or aging of the shaft seal (oil seal). This may be caused by excessive shaft vibration (resulting from worn bearings) or high back pressure of the oil leakage. The oil seal needs to be replaced, and the bearing clearance and the oil leakage pipeline should be inspected.

• Leakage at the joint: Check whether the connecting bolts are tightened evenly and according to the specified torque. The O-ring may fail due to aging, crushing, or defects in the sealing groove.

• Shell sand holes: Casting defect. Contact the supplier for handling.

Q10: The motor doesn't rotate and the system pressure surges, or the motor is abnormally hot. What's the cause? A10:

• No rotation and high pressure: This usually indicates that the internal moving parts are stuck. It could be due to contaminants entering, poor lubrication, or previous abnormal noises (such as damaged bearings) that were not addressed in time, causing the parts to get stuck. The machine must be immediately shut down for inspection.

• Abnormal fever:

1. Excessive internal leakage: The high-pressure oil leakage caused by wear generates a large amount of heat within the casing. By touching the oil drain pipe, if it feels unusually hot, it can be basically confirmed.

2. Mechanical friction: For example, if the bearing is damaged, it leads to dry friction.

3. Insufficient external cooling: The forging environment has a high temperature, so it is necessary to ensure that the cooling system is functioning effectively.

4. Excessive return oil back pressure or poor oil drainage: This results in the inability to remove heat in a timely manner.

IV. Maintenance and Lifespan

Q11: What are the key points for daily operation and maintenance?

A11: Preventive maintenance can significantly extend the service life in harsh forging environments:

Oil management: Regularly test the cleanliness, viscosity, moisture, and acid value of the oil, and replace the oil and filters at the scheduled time. Oil contamination is the primary cause of motor wear.
Regular inspection:
Fasteners: Regularly inspect and re-tighten the installation bolts to prevent loosening due to vibration.
Leakage point: Check for any leaks at all sealed areas.
Operation status: Listen for running sounds, monitor the temperature and vibration of the housing.
Long-term shutdown: If the equipment is not used for a long time, it is necessary to fill the motor housing with oil, seal the oil ports, and apply anti-rust grease to the output shaft.

Q12: Which factors have the greatest impact on the lifespan of this motor in the forging application? A12:

1. Oil cleanliness: This is a decisive factor. The forging site is dusty, and contaminants act like "abrasives", accelerating the wear of all friction pairs.

2. Installation alignment accuracy: Incorrect alignment will cause the bearings and shafts to bear additional loads, significantly shortening their lifespan.

3. Load spectrum: Operating continuously at the rated pressure or near the peak pressure, as well as experiencing unexpected severe impacts, will accelerate fatigue.

4. Maintenance: Whether regular inspections, oil replacement, and filter maintenance are strictly carried out.

5. Back pressure of oil discharge: Blockage of the oil discharge pipe or excessive back pressure is a common human-caused reason for the rapid damage of the shaft seal.

Q13: Can users perform the repair by themselves after a malfunction occurs?

A13: It is strongly advised against non-professionals to disassemble and repair. The five-star motor is a precision hydraulic component, and its assembly requires special tools and expertise. Especially, the matching of the flow distributor and the cylinder body, the pre-tightening force of the bearings, and the installation of the seals all have strict process requirements. Incorrect disassembly and assembly may lead to secondary damage or irrecoverable performance. In case of a malfunction, contact professional maintenance personnel or the supplier for handling.