Classification system and precautions for hydraulic power units

1. Classification of hydraulic pump stations

The classification of hydraulic pump stations needs to be combined with core requirements such as power source, size, and application scenario. Different types have significantly different adaptability. The specific classification is as follows:

(1) Classification by power source

DC type (12V/24V/48V)

AC type (110V/120V/220V/240V)

Petrol type

Diesel type

Gas type (propane/natural gas)

2. Classification by size

(1) Micro/small HPU

(2) Portable/compact HPU

(3) Large industrial HPU

3. Classification by Application

(1) By Output Characteristics:

Fixed Displacement Type (constant flow rate), Variable Displacement Type (flow rate adjustable as needed);

(2) By Versatility:

General Purpose Type (suitable for multiple scenarios), Special Purpose Type (customized for specific equipment);

(3) By Installation Method:

Skid-mounted (fixed to the ground), Rack-mounted (easy to move), Integrated Type (embedded inside the equipment);

(4) Core Selection Logic:

Match the corresponding hydraulic pump station type based on power supply conditions, operating environment (mobile/fixed, indoor/outdoor), load requirements (pressure/flow rate), and space limitations.

4. Hydraulic schematic diagrams for common industry applications

(1) Hydraulic circuit diagram of shaper:

showing how the hydraulic pump station drives the ram of the shaper to reciprocate and control the speed through the deceleration valve;

(2) Milling machine hydraulic circuit diagram:

showing the hydraulic control logic of table feed and milling cutter rotation.

(3) Hydraulic circuit diagram of the press:

Explain the circuit design of the hydraulic pump station to provide high-pressure power to the press;

(4) Hydraulic circuit diagram of forming and grinding machine:

showing the hydraulic control scheme of precision machining equipment.

5. Size Selection

(1) Tank Size Selection

Selection Principle: The volume should be 3-5 times the pump’s flow rate per minute;

Core Reason: To ensure sufficient oil supply, achieve heat dissipation (heat carried away during oil circulation needs to be diffused through the tank surface area), and allow contaminants to settle.

(2) Pressure Loss Calculation

Influencing Factors: Pipeline length, pipe diameter, number of joints, oil viscosity;

Calculation Purpose: To ensure that the pump output pressure meets the actual needs of the actuator, avoiding sluggish operation due to pressure loss.

(3) Component Selection Details

① Pump Selection:

Gear pumps for low-pressure scenarios, vane pumps for medium-high pressure scenarios, and plunger pumps for ultra-high pressure scenarios;

② Valve Selection:

The pressure rating must match the highest pressure of the system, and the valve diameter must be suitable for the flow rate (to avoid excessive pressure loss);

③ Hydraulic Cylinder Selection:

The cylinder diameter is determined by the applied force, and the stroke is determined by the working distance. Sealing materials compatible with the hydraulic fluid must be selected;

④ Filter Selection:

The filtration accuracy must be suitable for the component requirements (pumps and valves typically require 10-25μm), and the flow rate must be greater than the loop flow rate.