Variable Displacement Compressor Swash Plate Inertia Control
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Solution Overview
Problem
In variable displacement compressors, the moment of rotational movement based on the product of inertia in the swash plate's variable-angle direction significantly influences the compressor's power consumption, especially in high-speed rotation regions, where the optimal control of the swash plate's inclination angle to minimize power consumption and ensure secure compression operation is unclear.
Innovation Solution
A variable displacement compressor design featuring a swash plate with a minimum inclination angle regulating mechanism, inclination angle increasing and decreasing springs, and a conversion mechanism that adjusts the swash plate's inclination angle via pressure differences between the crank and suction chambers, ensuring the swash plate's inclination angle remains at a predetermined position that balances moments from inertia and spring forces, even at maximum rotational speeds, thereby reducing power consumption and maintaining secure compression operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the product of inertia in the variable-angle direction of the swash plate is reduced to minimize power consumption, then power consumption decreases, but the moment of rotational movement based on product of inertia becomes insufficient to control the swash plate inclination angle in the high-speed rotation region
Solution Approach 1:
The patent introduces an inclination angle increasing spring that generates a moment counteracting the moment of rotational movement based on product of inertia. This spring moment acts in the opposite direction to the inertia moment, balancing the swash plate inclination angle control in the high-speed rotation region where the inertia moment becomes dominant due to its proportionality to the square of rotational speed.
Solution Approach 2:
The patent modifies the swash plate structure by adding an inclination angle increasing spring with specific urging force characteristics. This changes the parameter of spring urging force to compensate for the increased inertia moment at high speeds, ensuring the swash plate maintains the necessary minimum inclination angle for reliable compression operation.
2Productivity
If the swash plate minimum inclination angle is regulated to approximately 0° to maximize compression efficiency, then compression efficiency improves, but power consumption increases in the high-speed rotation region due to the product of inertia effect
Solution Approach 1:
The inclination angle increasing spring provides a counterbalancing moment that offsets the excessive inertia moment at high speeds, allowing the swash plate to maintain a lower inclination angle (closer to 0°) without requiring excessive spring force, thereby reducing power consumption while preserving compression efficiency.
Solution Approach 2:
The patent creates a dynamic balance between the spring moment and the inertia moment that automatically adjusts with rotational speed. At low speeds, the spring moment dominates to maintain minimum inclination angle for compression efficiency; at high speeds, the inertia moment increases but is counterbalanced by the spring, allowing the system to adapt efficiently across the operating range.
3Reliability
If springs with high urging force are used to maintain swash plate inclination angle control, then inclination angle control improves, but the combined spring force creates excessive moment that increases power consumption
Solution Approach 1:
The patent optimizes the urging force parameter of the inclination angle increasing spring to achieve the minimum necessary force for reliable inclination angle control. By carefully selecting the spring constant and preload, the system maintains adequate control authority without creating excessive spring moments that would increase power consumption, particularly in the high-speed rotation region.
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 design effectively suppresses power consumption increases in high-speed rotation regions while ensuring secure swash plate motion and compression operation, with the swash plate's inclination angle positioned at a minimum angle that guarantees efficient discharge pressure and extends the lifespan of shaft sealing devices.
Implementation Method 1
an inclination angle increasing spring for urging the swash plate in a direction of increasing the inclination angle from the minimum inclination angle, an inclination angle decreasing spring for urging the swash plate in a direction of decreasing the inclination angle from a maximum inclination angle through the minimum inclination angle
Implementation Method 2
A moment of rotational movement based on a product of inertia in a variable-angle direction of the swash plate is proportional to a square of a rotational speed of the swash plate
Implementation Method 3
a conversion mechanism disposed between the pistons and the swash plate for converting rotational motion of the swash plate into reciprocating movement of the pistons
Implementation Method 4
a control valve for controlling a pressure in the crank chamber, which changes the inclination angle of the swash plate by varying a pressure difference between the crank chamber and the suction chamber
Data Source
AI summary
A variable displacement compressor having means for regulating the minimum inclination angle of a swash plate, a spring urging the swash plate in the inclination angle-increasing direction, and a spring urging the swash plate in the inclination angle-decreasing direction. The swash plate inclination angle is θa as the sum of the urging forces of both springs is zero, when the drive shaft is not rotated; and, when the drive shaft is rotated, its inclination angle is θb at which the sum of moments MS, MF is zero. Moment MS of rotational motion is based on selling the product of inertia in the variable-angle direction of the swash plate to decrease the inclination angle of the swash plate from θa. Moment MF is based on the combined urging force of both springs set so that the inclination angle θb is positioned at a minimum angle at maximum rotational speed.