Hydraulic Gear Pumps | Gear Pump Solutions | Hidroman
Hydraulic Gear Pumps | Gear Pump Solutions | Hidroman
Hydraulic Gear Pumps
Reliable Hydraulic Gear Pump Solutions for Industrial and Mobile Applications
Hydraulic gear pumps are widely used positive displacement pumps designed to convert mechanical power into hydraulic flow. Their simple and durable construction makes them a practical solution for industrial machinery, mobile equipment, agricultural machinery, hydraulic power units, and a wide range of OEM hydraulic systems.
Hidroman provides hydraulic gear pump solutions for applications where reliable oil flow, compact design, straightforward maintenance, and dependable operation are required.
Choosing the right gear pump requires more than selecting a pump based on pressure or displacement alone. Flow rate, operating pressure, pump speed, displacement, hydraulic oil viscosity, drive configuration, inlet conditions, and application requirements should all be evaluated together.
What Is a Hydraulic Gear Pump?
A hydraulic gear pump is a positive displacement pump that transfers hydraulic fluid from the inlet side to the outlet side through rotating gears.
As the gears rotate, hydraulic oil enters the pump through the suction port. The fluid is carried around the outer circumference of the gears and delivered to the pressure port. The meshing gears prevent the oil from simply flowing backward through the pump, allowing the pump to generate a controlled hydraulic flow.
Because gear pumps have a relatively simple mechanical design, they are widely used in applications where durability, compact dimensions, and cost-effective hydraulic power are important.
How Does a Gear Pump Work?
The operating principle of a hydraulic gear pump is based on the rotation of two or more gears inside a precision-machined housing.
The basic operating sequence is:
- The pump drive shaft rotates the gears.
- Hydraulic oil enters through the inlet port.
- Oil is carried in the spaces between the gear teeth and the pump housing.
- The rotating gears move the oil toward the outlet port.
- The oil leaves the pump and enters the hydraulic circuit.
- System resistance determines the pressure required for the application.
Does a Hydraulic Pump Create Pressure?
Technically, a hydraulic pump primarily creates flow, rather than directly creating pressure.
Pressure develops when the pump flow encounters resistance within the hydraulic system. This distinction is important when selecting a hydraulic gear pump because pump displacement, operating speed, system flow requirements, and system resistance must be considered together.
For this reason, a properly sized hydraulic gear pump should be selected according to the complete hydraulic circuit rather than a single pressure value.
Types of Hydraulic Gear Pumps
Hydraulic gear pumps are available in different designs depending on the application and required operating characteristics.
External Gear Pumps
External gear pumps use two externally meshing gears to transfer hydraulic fluid.
They are one of the most commonly used gear pump designs because of their compact construction, simple operating principle, and broad range of available displacements.
Typical applications include:
- Construction equipment
- Agricultural machinery
- Hydraulic power units
- Industrial machinery
- Material handling equipment
- Mobile hydraulic systems
- Auxiliary hydraulic circuits
- OEM hydraulic systems
Internal Gear Pumps
Internal gear pumps use an internal gear and an externally toothed gear operating together inside the pump housing.
Depending on the design, internal gear pumps can provide smooth flow characteristics and low noise levels, making them suitable for certain industrial hydraulic applications.
The appropriate pump design depends on the required flow rate, pressure, speed, oil viscosity, noise requirements, and operating conditions.
Hydraulic Gear Pump Selection
Selecting the correct hydraulic gear pump is critical for system efficiency, reliability, and service life.
The following parameters should be evaluated before selecting a pump.
- Pump Displacement
Pump displacement represents the theoretical volume of fluid delivered per revolution.
It is commonly expressed as:
cc/rev or cm³/rev
A larger displacement generally provides a higher theoretical flow rate at the same rotational speed.
- Flow Rate
Hydraulic flow is normally specified in GPM (gallons per minute) in the United States, while L/min is also commonly used in international technical documentation.
The theoretical relationship can be expressed as:
Flow Rate = Pump Displacement × Pump Speed
Actual flow will be affected by volumetric efficiency and operating conditions.
- Operating Pressure
The continuous operating pressure and maximum pressure rating of the pump must be compatible with the hydraulic system.
A pump should not be selected solely according to its maximum pressure rating. Continuous operating conditions, duty cycle, oil temperature, speed, and system requirements should also be considered.
Hidroman's current product information specifies gear pump configurations in approximately the 0.75–150 cc displacement range and up to 210 bar, depending on the specific pump configuration. Always verify the technical specifications of the selected model before application.
- Operating Speed
Pump speed, typically specified in RPM, has a direct effect on hydraulic flow.
The pump must be compatible with the speed of the selected drive system, such as:
- Electric motor
- Diesel engine
- Gasoline engine
- PTO drive
- Hydraulic motor
- Custom mechanical drive
Both minimum and maximum allowable speeds should be considered.
- Hydraulic Oil and Viscosity
Hydraulic fluid viscosity directly affects pump performance, efficiency, lubrication, and service life.
The selected hydraulic oil should comply with the pump manufacturer's specifications.
Oil temperature must also be considered because viscosity changes significantly with operating temperature.
- Inlet Conditions
Proper inlet conditions are essential for reliable gear pump operation.
The following factors should be checked:
- Suction line diameter
- Suction line length
- Hydraulic oil temperature
- Tank position
- Inlet pressure
- Fluid viscosity
- Suction line restrictions
An improperly sized suction line can increase inlet losses and contribute to cavitation.
Advantages of Hydraulic Gear Pumps
Hydraulic gear pumps are widely used because they offer several practical advantages.
Key advantages include:
- Simple mechanical design
- Durable construction
- Compact dimensions
- Straightforward maintenance
- Wide range of displacements
- Suitable for mobile hydraulic equipment
- Suitable for industrial hydraulic systems
- Cost-effective hydraulic solution
- Broad OEM application potential
However, a gear pump is not automatically the correct choice for every hydraulic system.
Applications requiring highly variable flow, very high efficiency, sophisticated control, or specific high-pressure performance may require alternative pump technologies such as axial piston or vane pumps.
Where Are Hydraulic Gear Pumps Used?
Hydraulic gear pumps are used across a wide range of industries and equipment.
Construction Equipment
Gear pumps can be used in auxiliary hydraulic circuits, attachments, lubrication systems, and other hydraulic functions on construction equipment.
Typical applications include:
- Excavators
- Wheel loaders
- Skid steer loaders
- Telehandlers
- Road construction equipment
- Material handling equipment
Agricultural Equipment
Hydraulic gear pumps are commonly used in agricultural machinery where dependable hydraulic flow is required.
Applications include:
- Tractors
- Sprayers
- Harvesting equipment
- Agricultural implements
- Material handling systems
Industrial Machinery
Gear pumps can be integrated into industrial hydraulic systems, including:
- Hydraulic presses
- Lifting equipment
- Production machinery
- Conveyor systems
- Clamping systems
- Specialized machinery
- Hydraulic power units
Hydraulic Power Units
Gear pumps are frequently used in hydraulic power units (HPUs) that supply hydraulic oil to cylinders, hydraulic motors, valves, and other components.
The pump should be selected together with the electric motor, reservoir, filtration system, pressure control valves, and other HPU components.
What to Consider When Buying a Hydraulic Gear Pump
When purchasing a hydraulic gear pump, price should not be the only consideration.
The following technical information should be established before selecting a model:
- Required flow rate
- Operating pressure
- Maximum pressure
- Pump displacement
- Operating speed
- Rotation direction
- Drive type
- Shaft configuration
- Mounting dimensions
- Inlet connection
- Outlet connection
- Hydraulic oil type
- Oil viscosity
- Operating temperature
- Duty cycle
- Filtration level
- Application environment
Providing these details allows the correct pump configuration to be identified more accurately.
Hydraulic Gear Pumps for OEM Applications
For OEM applications, the hydraulic gear pump should be evaluated as part of the complete hydraulic system.
Hidroman works with hydraulic applications where pump selection may need to be coordinated with:
- Hydraulic cylinders
- Hydraulic valves
- Hydraulic motors
- Hydraulic power units
- Hydraulic filtration systems
- Hydraulic reservoirs
- Electric motors
- Control systems
- Hoses and fittings
This system-level approach can help OEM manufacturers develop hydraulic solutions that are matched to their actual operating requirements.
Hidroman Hydraulic Gear Pump Solutions
Hidroman provides hydraulic engineering and component solutions for industrial and mobile hydraulic applications.
Our approach focuses on matching hydraulic components to the actual requirements of the machine or system rather than selecting components based on a single specification.
For hydraulic gear pump selection, our technical evaluation can include required flow, operating pressure, pump displacement, speed, drive configuration, hydraulic oil, and installation requirements.
Whether you are developing a new OEM machine, replacing an existing pump, or upgrading a hydraulic power unit, providing the basic operating parameters allows the appropriate pump configuration to be evaluated.
Request a Hydraulic Gear Pump Selection
Looking for the right hydraulic gear pump for your application?
Send Hidroman the following information:
- Required flow rate (GPM or L/min)
- Operating pressure (PSI or bar)
- Pump speed (RPM)
- Required displacement (cc/rev)
- Hydraulic oil type
- Drive type
- Shaft and mounting requirements
- Inlet and outlet connection details
- Application and machine type
Our engineering team can evaluate the application and help identify a suitable hydraulic gear pump configuration.
Hidroman – Hydraulic Engineering, OEM Solutions and Hydraulic System Components.