“A7H” Series Variable Displacement Piston Pumps

YUKEN A7H Series Core Technical Specifications

Key Specification Notes & Supplementary Parameters

• Pressure Conversion: The rated pressure of 35.0 MPa is equivalent to 350 kgf/cm², and the maximum pressure of 40.0 MPa is equivalent to 400 kgf/cm², realizing high-pressure performance that is higher than the A3H series, which is suitable for heavy-duty hydraulic systems[superscript:2].
• Control Types: The A7H series offers three main control modes to meet diverse system requirements: 01 type (pressure compensator control), 09 type (constant power control), and 09R type (external-mounted constant power control). The control mode is reflected in the model code, and detailed performance parameters vary slightly by control type.
• Efficiency Performance: Under the condition of 35.0 MPa (350 kgf/cm²) pressure and 1200 rpm shaft speed, the volumetric efficiency of the A7H series can reach 95% or above, and the overall efficiency can reach 90% or above, achieving energy saving and high efficiency in long-term operation.
• Hydraulic Oil Requirements: The series is compatible with petroleum-based anti-wear hydraulic oils (ISO VG 32 or 46) and fire-resistant hydraulic fluids (water-glycol and fatty acid ester types). The recommended viscosity range is 10 to 200 mm²/s at 0-80°C; if the viscosity exceeds 200 mm²/s, pre-warming operation is required before formal operation.
• Permissible Suction Pressure: The suction port pressure should be between -0.01 MPa and +0.5 MPa (gauge pressure) when operating at the rated speed. When using fire-resistant hydraulic fluids, the permissible suction pressure and speed range need to be adjusted according to the fluid type.
• Through Drive Function: Optional through drive allows direct mounting of an auxiliary or outboard pump (complying with SAE standards) on the driven side, realizing pump compounding and saving installation space.
• Model Composition: The model code includes oil type, displacement, mounting type, rotation direction, control mode, and port direction. For example, “M-A7H265-FR01S” indicates water-glycol fire-resistant oil, 270 cm³/rev displacement, flange mounting, clockwise rotation (viewed from the shaft end), pressure compensator control, and side port direction.

Installation & Operation Specifications

• Drain Piping Size: The recommended inner diameter of the drain pipe is 19 mm (3/4”) or more to ensure smooth oil drainage and avoid pressure buildup in the pump casing.
• Mounting Requirements: The pump supports flange and foot mounting; during installation, ensure the “filling port” is at the top to avoid air accumulation. The required pre-fill oil volume is 3.5 liters for standard models.
• Temperature Range: When using petroleum-based hydraulic oil, the normal operating temperature range is -20°C to 80°C; when using fire-resistant hydraulic fluids, the range is 10°C to 50°C (water-glycol type) or 10°C to 70°C (fatty acid ester type).
• Key Dimensions: For A7H180 models, the main installation dimensions (A×B×C) are 496 mm×358.5 mm×370 mm (01 control type) and 496 mm×358.5 mm×400 mm (09 control type); for A7H265 models, the dimensions are 575 mm×375.5 mm×411.5 mm (01 control type) and 575 mm×375.5 mm×432.5 mm (09 control type).
• Seal Material: The standard seal material is FKM (fluoro rubber), which has excellent high-temperature and oil resistance, adapting to the high-pressure and wide-temperature working environment of the A7H series.