Balancing Ring Hemishell Structure for High-Speed Washer Drums
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
High-end laundry washing machines with ball balancing rings face mechanical stress and leakage issues due to concentrated centrifugal forces at high rotation speeds, leading to microcracks and operational failures.
Innovation Solution
A toroidal balancing ring design featuring discrete and complementary annular hemishells with C-shaped cross sections, securely joined along mating annular rims, reduces mechanical stress and allows higher rotation speeds without structural issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the toroidal housing is made as a single piece or with conventional welding structure, then the structure is simple, but concentrated centrifugal forces at high rotation speeds cause microcracks and leakage
Solution Approach 1:
The toroidal housing is divided into two separate annular hemishells that are joined along mating annular rims. This segmentation distributes the concentrated centrifugal forces across multiple surfaces and reduces stress concentration at any single location, preventing microcrack formation and leakage while maintaining structural integrity at high rotation speeds
Solution Approach 2:
The mating annular rims are designed with specific local geometric features including frustoconical surfaces with controlled opening angles (20°-70°). These local quality enhancements create optimized stress distribution zones at the critical joining areas, allowing the structure to withstand high centrifugal forces without failure
2Reliability
If the toroidal housing is oversized to prevent leakage, then reliability improves, but the device complexity and manufacturing difficulty increase
Solution Approach 1:
Rather than oversizing a single monolithic housing, the invention segments the housing into two hemishells that join along annular rims. This approach achieves the necessary leakage prevention through distributed stress paths without requiring excessive material or complex internal structures, thereby avoiding increased device complexity
Solution Approach 2:
The housing employs composite construction with two hemishells made of potentially different materials or treatments, joined through precision-matched annular rims. This composite approach optimizes both reliability and structural efficiency without unnecessary complexity
3Reliability
If the toroidal housing is oversized to prevent leakage, then reliability improves, but welding complexity increases
Solution Approach 1:
The housing is segmented into two hemishells with mating annular rims that create controlled, localized welding zones. This segmentation allows for simpler, more manageable welding processes compared to welding a single large-thick housing, as the welds are concentrated at specific rim interfaces rather than distributed through a massive structure
Solution Approach 2:
The design changes the geometric parameters of the joining interface, specifically using frustoconical surfaces with optimized opening angles. This parameter optimization facilitates easier welding by creating ideal joint geometries that improve weld accessibility, penetration, and quality while preventing leakage
4Ease of manufacture
If conventional annular housing structure is used, then manufacturing is simpler, but mechanical stress concentrates at welding areas causing failure
Solution Approach 1:
By segmenting the housing into two hemishells joined at annular rims, the design distributes mechanical stresses across multiple surfaces and interfaces. This prevents stress concentration at any single welding area, allowing the use of standard manufacturing techniques while avoiding stress-related failures
Solution Approach 2:
The annular rims are designed with specific local geometric features including frustoconical surfaces that optimize stress distribution. These local quality enhancements at critical interfaces reduce overall mechanical stress while maintaining ease of manufacture through standardized construction methods
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 design effectively minimizes mechanical stress on the welding areas, prevents leakage, and allows the balancing ring to operate reliably at speeds exceeding 1000 rpm, with simplified assembly and reduced noise from balancing masses.
Implementation Method 1
a viscous liquid that damps out the movement of the spherical masses inside the inner cavity
Implementation Method 2
During spin phases, the spherical masses tend to group together and to move altogether inside the inner cavity so as to balance the unbalanced load (laundry) momentarily placed inside the drum
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
A laundry washing machine (1) having an outer casing (2) and comprising, inside said outer casing (2): a washing tub (3) adapted to contain the washing liquid; a rotatable drum (4) which is fitted in axially rotatable manner inside the washing tub (3) and is adapted to contain the laundry to be washed; and at least one balancing ring (13) which is rigidly secured to the rotatable drum (4) for reducing the vibrations of the drum (4); said at least one balancing ring (13) comprises: a nearly toroidal, annular housing (15) which is rigidly secured to the drum (4) and is internally provided with a closed annular inner cavity (16); and a number of balancing masses (17) accommodated in free movable manner inside said annular inner cavity (16); the annular housing (15) being divided into first (18) and second (19) discrete and complementary annular hemishells which are joined to one another so as to form/delimit the annular inner cavity (16) of said annular housing (15); said first (18) and second (19) annular hemishells being substantially coplanar and concentric to one another, having approximately C-shaped cross sections substantially complementary to one another, and being stably joined/ coupled to one another along corresponding first (18a, 19a) and second (18b, 19b) mating annular rims/edges which are arranged on opposite sides of a given intermediate plane (M) perpendicular to the central axis (B) of said annular housing (15).