Hydraulic Pump Lower-Limit Displacement for Quiet Pressure Holding
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Solution Overview
Problem
Existing hydraulic pressure supply devices face challenges in maintaining consistent hydraulic pressure across varying loads and temperatures, leading to increased rotational frequency of electric motors, noise, and inefficient part production due to fixed minimum discharge capacities and mechanical adjustments.
Innovation Solution
A hydraulic pressure supply device with a discharge capacity adjustment mechanism, pressure and rotational frequency detectors, and a controller that dynamically adjusts the discharge capacity and motor frequency to maintain pressure, reducing motor noise and improving efficiency by setting a lower limit discharge capacity that can be adjusted based on operational modes and temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the minimum discharge capacity of the pump is set to a fixed value, then the pump can maintain pressure under highest leakage conditions, but the electric motor size and power consumption increase unnecessarily under normal operating conditions
Solution Approach 1:
The pump's discharge capacity is made dynamically adjustable through a variable displacement mechanism. The swash plate angle can be varied continuously to change the piston displacement, allowing the pump to adapt its discharge capacity to actual system needs rather than operating at a fixed minimum capacity. This dynamic adjustment enables the system to maintain pressure reliability when needed while reducing power consumption during normal operation.
Solution Approach 2:
The invention changes the operational parameters of the pump by allowing continuous adjustment of the swash plate angle. This parameter change enables the discharge capacity to be optimized for different operating conditions - set to minimum for pressure keeping and increased when higher flow rates are needed, thereby resolving the contradiction between reliability and power consumption.
2Ease of manufacture
If the swash plate tilting angle is mechanically limited by a stopper, then the minimum discharge capacity is fixed, but the pump cannot adapt to different working conditions requiring different capacity levels
Solution Approach 1:
The mechanical stopper limiting the swash plate angle is replaced with a controllable mechanism that allows dynamic adjustment of the tilting angle within a safe range. This enables the pump to adapt its discharge capacity to different working conditions while maintaining mechanical simplicity through controlled movement boundaries rather than fixed mechanical stops.
Solution Approach 2:
The pump is designed with universal adaptability to handle multiple working conditions - from pressure keeping mode with minimum discharge capacity to high-flow modes with increased capacity. The same pump mechanism can serve different functions by adjusting the swash plate angle, eliminating the need for multiple specialized pumps for different applications.
3Reliability
If the electric motor rotational frequency is increased to compensate for internal leakage, then the flow rate shortage is compensated, but motor noise increases significantly
Solution Approach 1:
Instead of compensating for internal leakage by continuously running the motor at high rotational frequency, the system dynamically adjusts the pump's discharge capacity to match actual flow requirements. This eliminates the need for excessive motor speed increases, thereby reducing noise while maintaining the ability to compensate for leakage when necessary.
Solution Approach 2:
The system changes the approach from modifying motor speed parameters to adjusting pump discharge capacity parameters. By optimizing the pump's displacement rather than the motor's rotational frequency, the system achieves flow rate compensation without the harmful side effect of increased motor noise.
4Adaptability or versatility
If different pumps with different minimum discharge capacities are designed for different use modes, then each pump is optimized for its specific use, but manufacturing cost increases due to non-mass-producible parts
Solution Approach 1:
A single universal pump design with variable displacement capability replaces the need for multiple specialized pumps. The same pump can be configured for different minimum discharge capacities by adjusting the swash plate mechanism, allowing one pump model to serve multiple applications that previously required different pump types, thereby enabling mass production and reducing manufacturing costs.
Solution Approach 2:
The variable displacement mechanism allows a single pump to dynamically adapt to different use modes and requirements. Rather than manufacturing different fixed-capacity pumps for different applications, one dynamic pump can be adjusted to meet various operational needs, simplifying the supply chain and reducing manufacturing complexity.
Data Source
AI summary
A hydraulic pressure supply device includes: a hydraulic pump capable of changing a discharge capacity; an electric motor capable of changing a rotational frequency; a discharge capacity adjustment mechanism capable of adjusting the discharge capacity of the pump between a maximum and minimum discharge capacity; a pressure detector configured to detect pressure of an operating liquid discharged from the pump; a rotational frequency detector configured to detect the rotational frequency of the motor; and a controller configured to control operations of the motor and adjustment mechanism based on the rotational frequency, detected by the detector, to keep pressure of an actuator at arbitrary pressure, wherein, the controller controls the operation of the adjustment mechanism so the discharge capacity of the pump becomes a set lower limit discharge capacity. The set lower limit discharge capacity is set to be larger than the minimum discharge capacity and be adjustable by the controller.