Rotary Compressor Balance Weight Recess for Rivet Head
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Solution Overview
Problem
The existing rotary compressor balance weight mechanisms suffer from inadequate reduction of agitation loss due to unevenness caused by counterbores in the flat portions, which affects the mass balance and efficiency of the compressor.
Innovation Solution
The rotary compressor incorporates a balance weight mechanism with a flat surface at the axial end of the drive shaft, covering the rivet head and using a press-fit attachment to the rotor core, eliminating counterbore unevenness and preventing centrifugal force from deforming the rotor, thus reducing agitation loss and maintaining motor efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a counterbore is provided in the flat portion of the balance weight mechanism to fit the rivet head, then the rivet can be securely attached, but the flat portion becomes uneven which increases agitation loss
Solution Approach 1:
The invention extracts the rivet head from the visible flat portion surface by providing a recess that receives and hides the rivet head. This removes the source of unevenness (the protruding rivet head) from the rotating surface, thereby reducing agitation loss while maintaining secure attachment through the rivet in the recess
Solution Approach 2:
The recess serves multiple functions: it provides attachment for the rivet to secure the balance weight mechanism to the rotor, and simultaneously creates a flush surface that reduces agitation loss. This multi-functionality resolves the contradiction between secure attachment and smooth surface requirement
2Strength
If welding is used to attach the balance weight mechanism to the rotor, then strong attachment is achieved, but the electromagnetic steel sheets may be strained or demagnetized
Solution Approach 1:
The invention replaces the thermal welding process with a mechanical press-fit attachment method. The balance weight mechanism is pressed onto the drive shaft to form an interference fit, achieving strong attachment without thermal effects that could strain or demagnetize the electromagnetic steel sheets, thereby preserving motor efficiency
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
The solution effectively reduces agitation loss and prevents rotor deformation, enhancing the compressor's efficiency and reliability by ensuring a smooth, even surface for the balance weight mechanism and securely attaching it to the drive shaft without welding, which can cause strain or demagnetization.
Implementation Method 1
a balance weight mechanism (60, 70) which causes centrifugal force to act on the drive shaft (40)
Implementation Method 2
a rivet (34) which clamps the rotor core (32a) at both axial ends of the rotor core (32a)
Implementation Method 3
an insertion portion (68, 78) into which drive shaft (40) is press fit
Data Source
AI summary
A rotary compressor includes a casing, an electric motor, a compression mechanism and a balance weight mechanism. The electric motor includes a stator fixed to the casing, and a rotor. The compression mechanism is connected to the electric motor via a drive shaft. The balance weight mechanism is configured to cause centrifugal force to act on the drive shaft. The rotor includes a rotor core including a plurality of stacked electromagnetic steel sheets, and a rivet configured to clamp the rotor core at axial ends of the rotor core. The balance weight mechanism includes an insertion portion into which drive shaft is press fit, and a flat portion forming a flat surface at an axial end of the drive shaft. The balance weight mechanism is disposed at an axial end portion of the rotor to cover a head of the rivet.