Hydraulic Power Source Segmentation for Injection Molding
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Solution Overview
Problem
Injection molding machines with servo motors driving hydraulic pumps face issues of high energy loss, risk of hydraulic pump damage due to heat accumulation, and the need for large-capacity servo motors, leading to inefficiencies and increased costs.
Innovation Solution
An injection molding machine configuration with a first main hydraulic power source and an auxiliary hydraulic power source, where the first main hydraulic power source operates at constant rotational speed and has variable capacity, and the auxiliary power source is driven by a servo motor with controlled rotational speed, using a check valve to regulate inflow and a switching unit to manage oil supply, allowing for efficient pressure and flow rate control without increasing motor size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If servo motors are used to drive hydraulic pumps for pressure control, then control stability is improved, but energy loss increases due to low-speed operation
Solution Approach 1:
The hydraulic power source is divided into a main hydraulic power source (with constant rotational speed motor and variable capacity pump) and an auxiliary hydraulic power source (with servo motor and fixed capacity pump). The auxiliary power source is selectively activated based on whether flow rate control or pressure control is required, allowing the system to benefit from servo motor control stability only when necessary.
Solution Approach 2:
The system dynamically switches between the main hydraulic power source and the auxiliary hydraulic power source based on control requirements. The switching unit changes the connection state between the auxiliary discharge pipe and the junction pipe according to whether flow rate control or pressure control is needed, optimizing energy efficiency while maintaining control performance.
2Measurement precision
If servo motors operate at high load for pressure control, then positioning precision is improved, but motor capacity must be increased
Solution Approach 1:
The hydraulic power source is segmented into main and auxiliary components. The auxiliary hydraulic power source with servo motor is only activated when positioning precision is required (during flow rate control), while the main hydraulic power source handles high-load pressure control operations, allowing the servo motor to be smaller in capacity.
Solution Approach 2:
The servo motor is positioned in the auxiliary hydraulic power source which is only connected to the system when precise flow rate control is needed. This local deployment allows the servo motor to provide high positioning precision only where needed, rather than requiring a large-capacity servo motor for all operations.
3Stress or pressure
If hydraulic pumps operate at low discharge during pressure control, then pressure maintenance is improved, but pump damage risk increases due to heat accumulation
Solution Approach 1:
The system segments pressure control functions between two power sources: the main hydraulic power source handles continuous pressure maintenance with its variable capacity pump operating at optimal speed, while the auxiliary hydraulic power source with servo motor is only activated when flow rate control is needed, preventing heat accumulation in the auxiliary pump.
Solution Approach 2:
The switching unit acts as an intermediary that controls when the auxiliary hydraulic power source connects to the system. By managing the connection state between the auxiliary discharge pipe and junction pipe, the switching unit ensures the auxiliary pump only operates when necessary, preventing continuous low-discharge operation and heat accumulation.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration enables high-efficiency actuation of hydraulic actuators with reduced energy loss and motor size, preventing pump damage and lowering operational costs by optimizing hydraulic pressure and flow rate control.
Implementation Method 1
an auxiliary discharge pipe through which the working oil discharged from the auxiliary hydraulic pump flows, and a check valve that is provided at the auxiliary discharge pipe to regulate the inflow of working oil to the auxiliary hydraulic pump
Implementation Method 2
a first main hydraulic pump that is driven by the rotational driving of the first constant rotational speed motor to discharge working oil
Implementation Method 3
a hydraulic supply device that supplies working oil to the hydraulic actuators to actuate the hydraulic actuators
Data Source
AI summary
A hydraulic supply device of an injection molding machine is provided with: a first main hydraulic power source including a first main hydraulic pump having a variable capacity and driven by a first constant rotational speed motor, and a first main discharge pipe through which working oil flows; an auxiliary hydraulic power source including an auxiliary hydraulic pump driven by a servo motor and operated at a specific capacity, an auxiliary discharge pipe through which the working oil flows, and a check valve that regulates the inflow of working oil to the auxiliary hydraulic pump; a hydraulic control unit that controls the first main hydraulic power source and the auxiliary hydraulic power source; a junction pipe at which the first main discharge pipe and the auxiliary discharge pipe join; and a switching unit that switches the supply/non-supply of working oil for a hydraulic actuator.