Application Range, Design Characteristics and Technical Specifications Analysis
1. Introduction
Sauer-Danfoss / Danfoss hydraulic pumps are widely recognized as one of the leading solutions for mobile hydraulic systems, especially in construction machinery, agriculture equipment, forestry machines, mining vehicles, and industrial mobile applications. Among the most important pump families are the ERR, KRR, GRR, JRR, LRR, and FRR series, which belong to the variable displacement axial piston pump family designed for open-circuit hydraulic systems.
Although these models share similar operating principles, they are designed for different power requirements, displacement ranges, installation conditions, and machine applications. The main differences are related to:
- Pump frame size
- Maximum displacement
- Flow capability
- Pressure capability
- Torque capacity
- Physical dimensions
- Weight
- Application level
The correct selection of hydraulic pump size is critical because the pump determines the hydraulic system’s working speed, power efficiency, fuel consumption, and overall machine performance.
2. Basic Design Principle
ERR, KRR, GRR, JRR, LRR, and FRR pumps use a variable displacement axial piston swash plate design.
The basic operating principle:
- The drive shaft rotates the cylinder block.
- Multiple pistons move axially inside the cylinder block.
- The swash plate angle determines piston stroke.
- Changing the swash plate angle changes pump displacement.
- Hydraulic flow output is adjusted according to system demand.
This variable displacement design provides several advantages:
- High efficiency
- Excellent controllability
- Reduced energy consumption
- Lower heat generation
- High power density
- Long service life
These advantages make the pumps suitable for modern mobile hydraulic equipment requiring precise and efficient power control.
3. Model Naming Structure
A typical model example:
ERR147
Meaning:
| Code | Description |
|---|---|
| E | Series 45 family |
| RR | Rotation direction configuration |
| 147 | Maximum displacement (cm³/rev) |
Rotation designation:
| Code | Rotation |
|---|---|
| ERR | Right rotation |
| ERL | Left rotation |
Other frame codes:
| Series | General Size Class |
|---|---|
| FRR | Small displacement |
| LRR | Medium displacement |
| JRR | Medium-large displacement |
| GRR | Large displacement |
| KRR | Heavy-duty large displacement |
| ERR | Extra-large Series 45 displacement |
(The exact displacement range depends on generation, control option, and configuration.)
4. Overall Technical Comparison
| Series | Size Level | Typical Displacement Range | Flow Capacity | Application Level |
|---|---|---|---|---|
| FRR | Small | Approx. 20–45 cm³/rev | Low-medium flow | Compact machinery |
| LRR | Medium-small | Approx. 45–75 cm³/rev | Medium flow | Agricultural and mobile equipment |
| JRR | Medium | Approx. 75–100 cm³/rev | Medium-high flow | Construction machinery |
| GRR | Large | Approx. 100–130 cm³/rev | High flow | Heavy equipment |
| KRR | Heavy duty | Approx. 130–160 cm³/rev | Very high flow | Mining and large machinery |
| ERR | Extra large | Approx. 130–250 cm³/rev | Maximum flow | Heavy mobile hydraulic systems |
5. FRR Series Hydraulic Pump
Product Position
The FRR series represents the smaller displacement range of Sauer-Danfoss variable piston pumps.
It is designed for machines requiring:
- Compact hydraulic systems
- Lower power consumption
- Precise hydraulic control
- Limited installation space
Technical Characteristics
Typical specifications:
| Parameter | FRR Series |
|---|---|
| Pump Type | Variable displacement axial piston pump |
| Circuit Type | Open circuit |
| Design | Swash plate axial piston |
| Displacement | Approx. 20–45 cm³/rev |
| Pressure Rating | Approx. 280–310 bar |
| Peak Pressure | Approx. 350 bar |
| Rotation | Right / Left rotation versions |
| Control | Hydraulic, electric, servo options |
| Installation | SAE mounting |
Application Range
Compact Construction Equipment
FRR pumps are commonly used in:
- Mini excavators
- Compact loaders
- Small drilling machines
- Small rollers
Because of their compact design, they are ideal where installation space is limited.
Agricultural Machinery
Applications include:
- Small tractors
- Sprayers
- Harvesting equipment
- Agricultural attachments
Advantages:
- Low energy consumption
- Smooth operation
- Easy control
Industrial Mobile Equipment
Examples:
- Small lifting platforms
- Hydraulic power units
- Special vehicles
6. LRR Series Hydraulic Pump
Product Position
The LRR series is a medium displacement pump designed for general mobile hydraulic applications.
It provides a balance between:
- Flow output
- Efficiency
- Size
- Cost
Technical Specifications
| Parameter | LRR Series |
|---|---|
| Displacement | Approx. 45–75 cm³/rev |
| Working Pressure | Approx. 310 bar |
| Peak Pressure | Approx. 350–400 bar |
| Design | Variable axial piston |
| Circuit | Open circuit |
| Control | Manual, hydraulic, electric |
| Efficiency | High volumetric efficiency |
Application Range
Excavators
Used for:
- Main hydraulic systems
- Boom and arm operation
- Auxiliary attachments
Agricultural Equipment
Typical machines:
- Medium tractors
- Combine harvesters
- Forestry equipment
Municipal Vehicles
Applications:
- Snow removal trucks
- Road maintenance vehicles
- Utility vehicles
7. JRR Series Hydraulic Pump
Product Position
The JRR series is a medium-to-large displacement pump designed for machines requiring higher hydraulic power.
It provides:
- Higher flow
- Greater torque capability
- Improved productivity
Technical Parameters
| Parameter | JRR Series |
|---|---|
| Displacement | Approx. 75–100 cm³/rev |
| Pressure | Up to 310 bar |
| Peak Pressure | Up to 400 bar |
| Flow Capability | Medium-high |
| Structure | Axial piston variable pump |
| Control Options | Multiple displacement controls |
Application Range
Construction Machinery
Used in:
- Medium excavators
- Wheel loaders
- Road construction equipment
Forestry Machines
Applications:
- Timber harvesters
- Forwarders
The pump provides stable operation under rapidly changing loads.
Material Handling
Used in:
- Telehandlers
- Crane vehicles
- Industrial loaders
8. GRR Series Hydraulic Pump
Product Position
GRR pumps are designed for large mobile machines requiring higher hydraulic power.
They provide:
- Large displacement
- High flow
- Strong load capability
Technical Parameters
| Parameter | GRR Series |
|---|---|
| Displacement | Approx. 100–130 cm³/rev |
| Pressure | Approx. 310 bar |
| Peak Pressure | 400 bar |
| Flow | High |
| Power Density | High |
| Working Condition | Heavy-duty |
Application Range
Large Construction Equipment
Examples:
- Large excavators
- Wheel loaders
- Mining loaders
Road Machinery
Applications:
- Large milling machines
- Asphalt pavers
- Heavy rollers
Mining Equipment
Used for:
- Drilling rigs
- Underground machines
- Mining transport equipment
9. KRR Series Hydraulic Pump
Product Position
KRR represents a heavy-duty pump class designed for demanding applications requiring maximum hydraulic power.
It is commonly selected for:
- High horsepower machines
- Continuous operation
- Severe working environments
Technical Parameters
| Parameter | KRR Series |
|---|---|
| Displacement | Approx. 130–160 cm³/rev |
| Pressure | 310 bar |
| Peak Pressure | 400 bar |
| Flow Output | Very high |
| Duty Level | Heavy industrial |
Application Range
Mining Machinery
Applications:
- Mining loaders
- Drilling machines
- Heavy transport vehicles
Large Construction Equipment
Used in:
- Large excavators
- Piling machines
- Heavy cranes
Forestry Equipment
Suitable for:
- Large timber harvesters
- Wood processing machines
10. ERR Series Hydraulic Pump
Product Position
ERR series represents one of the largest displacement configurations in this family.
Typical models:
- ERR130
- ERR147
- ERR180
- ERR210
- ERR250
Technical Parameters
| Parameter | ERR Series |
|---|---|
| Displacement | Approx. 130–250 cm³/rev |
| Pressure | Up to 310 bar |
| Peak Pressure | Up to 400 bar |
| Flow | Extremely high |
| Efficiency | High |
| Rotation | Right-hand rotation |
Application Range
Heavy Construction Machinery
Used in:
- Large excavators
- Mining loaders
- Piling equipment
Road Construction Machinery
Applications:
- Large asphalt pavers
- Milling machines
- Heavy compactors
Marine and Industrial Applications
Used in:
- Hydraulic drive systems
- Heavy winches
- Special vehicles
11. Key Differences Between Six Series
1. Displacement Difference
The biggest difference is displacement.
Small displacement:
FRR → LRR
Medium:
JRR
Large:
GRR → KRR → ERR
Larger displacement means:
- Higher oil flow
- Greater hydraulic power
- Higher machine productivity
2. Power Capability Difference
Formula:
Hydraulic Power:
P = Pressure × Flow ÷ 600
A larger displacement pump can generate:
- Higher flow
- Higher output power
- Faster actuator movement
Therefore:
FRR is suitable for compact equipment.
ERR/KRR are suitable for heavy-duty machinery.
3. Machine Size Difference
| Machine Size | Recommended Pump |
|---|---|
| Mini equipment | FRR |
| Medium equipment | LRR |
| Standard construction equipment | JRR |
| Large construction equipment | GRR |
| Heavy mining equipment | KRR |
| Maximum power machines | ERR |
12. Selection Guide
When selecting between FRR, LRR, JRR, GRR, KRR, and ERR, engineers normally consider:
1. Required Flow
Higher flow requirement:
Choose larger displacement:
GRR / KRR / ERR
2. Engine Power
Small engine:
FRR / LRR
High horsepower engine:
GRR / KRR / ERR
3. Machine Working Condition
Light duty:
FRR
Medium duty:
LRR / JRR
Heavy duty:
GRR / KRR / ERR
4. Installation Space
Compact machines:
FRR / LRR
Large machines:
GRR / KRR / ERR
13. Conclusion
The Sauer-Danfoss ERR, KRR, GRR, JRR, LRR, and FRR hydraulic pump series represent different performance levels within the variable displacement axial piston pump family.
The main differences are:
| Series | Main Feature |
|---|---|
| FRR | Compact and efficient small displacement pump |
| LRR | Medium pump for general mobile applications |
| JRR | Balanced performance for construction equipment |
| GRR | High flow pump for large machines |
| KRR | Heavy-duty pump for severe applications |
| ERR | Maximum displacement and power capability |
In practical applications:
- FRR is ideal for compact agricultural and construction machines.
- LRR provides reliable performance for medium mobile equipment.
- JRR is widely used in general construction machinery.
- GRR serves large equipment requiring higher hydraulic output.
- KRR is designed for heavy-duty and mining applications.
- ERR delivers maximum hydraulic power for the most demanding machines.
By selecting the correct displacement size and control configuration, these pumps provide excellent efficiency, durability, and productivity for modern mobile hydraulic systems worldwide.
