QT6252-100-63-BP-Z SUMITOMO Hydraulic Gear Pump 100/63cc 250bar

Product Overview

The QT Series is an internal gear pump product line from SUMITOMO Precision Products Co., Ltd. (SPP), a globally recognized brand in hydraulic transmission technology. SUMITOMO QT Series gear pumps are widely used in injection molding machines, die-casting machines, CNC machine tools, hydraulic presses, and other precision industrial equipment.

The QT Series internal gear pumps feature a special gear tooth design that minimizes the enclosed volume, delivering exceptional quiet operation—noise levels remain nearly constant even as pressure or speed increases, with excellent sound quality that is barely perceptible during operation. The QT Series offers three pressure grades (low pressure 6.9 MPa, medium pressure 13.7 MPa, and high-pressure series), with displacements ranging from 5 to 250 cm³/rev.

This page features three SUMITOMO QT Series models: QT6252-100-63-BP-Z, QT6252-125-63-BP-Z, and QT62-125F-BP-Z. These are original specification models that enable direct form-fit-function interchangeability with original SUMITOMO units—no modifications to piping or mounting interfaces required. Our replacement solutions strictly adhere to SUMITOMO technical standards and undergo 100% simulated in-service testing to ensure performance, reliability, and service life identical to OEM products.

Technical Specifications 

Model 1: QT6252-100-63-BP-Z (Tandem Pump)

Applicable Model:

• QT6252-100-63-BP-Z

Model Code Breakdown (per SUMITOMO naming convention):

• QT: Internal Gear Pump Series

• 6252: Tandem pump housing and shaft specifications

• 100: First section displacement (100 cm³/rev)

• 63: Second section displacement (63 cm³/rev)

• BP: Tandem pump configuration

• Z: Special seals or custom configuration

This Model Detailed Specifications:

• Product Series: SUMITOMO QT Tandem Internal Gear Pump

• Pump Type: Internal Gear Pump

• First Section Displacement: 100 cm³/rev

• Second Section Displacement: 63 cm³/rev

• Rated Operating Pressure: 25 MPa (250 bar / 3,625 psi)

• Body Material: High-Strength Cast Iron

• Fluid Compatibility: Hydraulic Oil

• Operating Temperature: 30 – 90°C

• Weight: Approx. 10 kg

Model 2: QT6252-125-63-BP-Z (Tandem Pump)

Applicable Model:

• QT6252-125-63-BP-Z

Model Code Breakdown:

• QT: Internal Gear Pump Series

• 6252: Tandem pump housing and shaft specifications

• 125: First section displacement (125 cm³/rev)

• 63: Second section displacement (63 cm³/rev)

• BP: Tandem pump configuration

• Z: Special seals or custom configuration

This Model Detailed Specifications:

• Product Series: SUMITOMO QT Tandem Internal Gear Pump

• Pump Type: Internal Gear Pump

• First Section Displacement: 125 cm³/rev

• Second Section Displacement: 63 cm³/rev

• Rated Operating Pressure: 25 MPa (250 bar / 3,625 psi)

• Body Material: High-Strength Cast Iron

• Fluid Compatibility: Hydraulic Oil

• Operating Temperature: 30 – 90°C

• Weight: Approx. 10 kg

Model 3: QT62-125F-BP-Z (Single Pump)

Applicable Model:

• QT62-125F-BP-Z

Model Code Breakdown (per SUMITOMO naming convention):

• QT: Internal Gear Pump Series

• 62: QT62 Series (QT6 mounting group)

• 125: Displacement (125 cm³/rev)

• F: Flange mounting configuration

• BP: Specific configuration identifier

• Z: Special seals or custom configuration

This Model Detailed Specifications (per SUMITOMO official documentation):

• Product Series: SUMITOMO QT62 Internal Gear Pump

• Pump Type: Internal Gear Pump

• Geometric Displacement: 125 cm³/rev

• Rated Operating Pressure: 25 MPa (250 bar / 3,625 psi)

• Maximum Operating Pressure: 31.4 MPa (314 bar / 4,550 psi)

• Maximum Speed: 1,800 min⁻¹

• Rotation Direction: Clockwise (Right-Hand)

• Pulsation Rate: 0.02 MPa (Superior stability)

• Body Material: High-Strength Cast Iron

• Fluid Compatibility: Hydraulic Oil

• Operating Temperature: 30 – 90°C

• Weight: Approx. 82 kg

Key Technical Advantages

1. Internal Gear Construction with Special Tooth Design — Ultra-Low Noise Operation
The QT Series features internal gear pump construction with a special tooth design that minimizes the enclosed volume, effectively eliminating “trapped volume” cavitation. Noise levels remain nearly constant even as pressure or speed increases, with excellent sound quality that is barely perceptible during operation. This makes it the ideal choice for noise-sensitive applications such as injection molding and die-casting machines.

2. Forced Lubrication with Non-Contact Design — Superior Durability
The QT Series features a simple construction with forced lubrication on sliding surfaces, with no direct contact between functional components. As a result, component wear is minimal. Even when using low-lubricity fluids (such as water-glycol), wear is remarkably low. This design ensures high reliability and extended service life under long-term operation.

3. High Pressure Capacity for Heavy-Duty Applications
The QT Series operates stably at high speeds under 250 bar (25 MPa) pressure, with minimal wear even when using standard hydraulic oil. The QT62-125F-BP-Z achieves a maximum pressure of 314 bar (31.4 MPa / 4,550 PSI), delivering exceptional pressure capacity in its class.

4. Extremely Low Pressure Pulsation — Superior System Stability
The QT Series achieves a pressure pulsation rate as low as 0.02 MPa. This ultra-low pulsation ensures smoother hydraulic system operation, reduces system vibration and noise, and extends the service life of other system components.

5. Modular Design with Flexible Single/Tandem Configurations
The QT Series offers five mounting groups (QT2/QT3/QT4/QT5/QT6) with displacements ranging from 5 to 250 cm³/rev. Both single pumps (e.g., QT62-125F-BP-Z) and tandem pumps (e.g., QT6252-100-63-BP-Z, QT6252-125-63-BP-Z) are available, enabling flexible selection based on specific equipment requirements.

Application Areas

• Injection Molding Machinery: Injection molding machine hydraulic systems (servo hydraulic systems)

• Die-Casting Machinery: Die-casting machine hydraulic systems

• CNC Machine Tools: CNC lathes and machining center hydraulic systems

• Heavy-Duty Hydraulic Presses: Hydraulic press power systems

• Construction Machinery: Large construction equipment hydraulic systems

• Industrial Hydraulic Systems: Hydraulic power units for various industrial equipment

Expert Maintenance Tips

1. Installation Precautions

• The QT Series is a uni-directional rotation pump—verify that the system‘s required rotation direction matches the pump’s identification marking before installation. The QT62-125F-BP-Z features clockwise (right-hand) rotation.

• Ensure coaxial alignment between the pump and drive shaft; flexible couplings are recommended to avoid radial loads on the pump shaft.

• The suction line diameter must not be smaller than the pump inlet port to prevent cavitation.

2. Fluid Management

• Use hydraulic oils with viscosity grades equivalent to ISO VG 46～68. For pressures above 70 kgf/cm², anti-wear hydraulic oils are recommended.

• Recommended operating viscosity is 20～500 cSt (mm²/s).

• Operating temperature should be maintained within 0℃～60℃.

• For fire-resistant fluids (water-glycol, phosphate ester, W/O emulsions, etc.), consult the manufacturer.

• Prime the pump by filling the housing with hydraulic fluid through the suction port before initial start-up. Never run the pump dry.

3. Filtration System Requirements

• Install a 150 μm filter on the suction side.

• Use a 25 μm filter on the discharge side.

• Magnetic filters are recommended to effectively extend service life.

• Prevent contaminants or water from entering the hydraulic fluid. If the fluid changes color, separates into layers, or shows white bubbles, it has degraded and must be replaced immediately.

4. Start-Up & Commissioning

• Use jog start method for initial start-up; verify correct rotation direction before continuous operation.

• Allow the pump to run under no-load (low pressure) conditions for 2-3 minutes to purge air and ensure proper lubrication.

• Gradually increase to operating pressure while monitoring noise, temperature, and system pressure for normal operation.

5. Routine Maintenance

• The QT gear pump itself is maintenance-free; however, regular maintenance of the entire hydraulic system is essential for trouble-free pump operation.

• Inspect system fluid cleanliness and condition every 1,000-2,000 operating hours.

• Regularly replace return line filters and suction strainers to prevent contaminant ingress into the pump body.