Positive Displacement Machine Vibration Torque Reduction
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Solution Overview
Problem
Existing positive displacement machines experience increased vibration due to the torque about the Y axis, which is difficult to eliminate, especially when the maximum swing angle is increased by reducing arm lengths or piston diameters, leading to inefficiencies and mechanical friction losses.
Innovation Solution
The positive displacement machine incorporates a support structure where the first arm portions are constrained by second arm portions in a movable manner on an axis parallel to the rotation axis of the shaft members, allowing only motion along this axis, reducing mechanical friction and increasing the maximum swing angle while minimizing vibration torque.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If the arm lengths are reduced to increase the maximum swing angle, then the swing angle is increased, but the torque about the Y axis increases causing increased vibration
Solution Approach 1:
The patent introduces counterweight members that generate counterbalancing forces to offset the vibration torque produced by the reciprocating and swinging motion. These counterweights are strategically positioned to create opposing moments that cancel out the harmful Y-axis torque, allowing the system to achieve larger swing angles without proportionally increasing vibration.
2Loss of energy
If the piston diameters are reduced to decrease bearing load and mechanical friction loss, then the mechanical friction loss is reduced, but the stroke increases leading to increased maximum swing angle and vibration
Solution Approach 1:
The counterweight members are designed to compensate for the increased vibration torque that results from larger strokes necessitated by smaller piston diameters. By generating opposing moments, the counterweights enable the system to operate with reduced piston sizes and lower friction losses without suffering from excessive vibration.
Solution Approach 2:
The patent modifies the mass distribution and inertial parameters of the moving components, particularly through the addition of counterweight members with specific masses and positions. This changes the overall dynamic characteristics of the system, allowing for larger swing angles and smaller piston diameters while maintaining acceptable vibration levels through parameter optimization.
3Productivity
If the maximum swing angle is increased to improve performance, then the efficiency is improved, but the torque about the Y axis that is difficult to eliminate increases causing increased vibration
Solution Approach 1:
The counterweight members are specifically designed to address the vibration torque issue that becomes more pronounced at larger swing angles. By generating counterbalancing moments, they enable the system to operate at higher swing angles and improved efficiency levels without being constrained by excessive vibration that would otherwise limit performance.
Data Source
Figure 1
Figure 2(a)~3(e)
Figure 4(a)~5
AI summary
Second arm portions 54a and 54b formed as inner peripheral cylindrical surfaces about a center axis that is an axis parallel to a rotation axis of shaft members 50a and 50b are configured to support first arm portions 44a and 44b, such that centers of sphere P1a and P1b of outer peripheral spherical portions 45a and 45b mounted to the first arm portions 44a and 44b are constrained on a center axis of the second arm portions 54a and 54b. Even when a swing piece amplitude angle (maximum swing angle) is increased by decreasing the arm length of the first arm portions 44a and 44b or when the swing piece amplitude angle (maximum swing angle) is increased with an increase in piston stroke by decreasing the diameter (bore diameter) of pistons 42a and 42b, this configuration reduces a vibration torque of vibrating the periphery, compared with a prior art positive displacement machine. This accordingly provides a lower vibration-type positive displacement machine of the small size and the high efficiency.