Dishwasher Spray Arm Bearing Recesses to Prevent Dirt Jamming
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Solution Overview
Problem
Dishwasher spray arm arrangements often experience blockages due to dirt accumulation in bearing points, leading to increased friction and potential jamming, especially in smaller spray arms with reduced drive torque.
Innovation Solution
The spray arm arrangement features widening recesses in the bearing sections, allowing for easier dirt removal and reduced friction, with obliquely angled side walls and mold separation areas to enhance dirt washing and maintain hydraulic integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If rectangular recesses are provided in bearing sections to flush away dirt particles, then dirt removal capability is improved, but dirt accumulation in recesses can still occur leading to blockage
Solution Approach 1:
The recesses are designed with an expanding shape where the outlet cross-section is larger than the inlet cross-section. This asymmetric geometry prevents dirt accumulation by ensuring that dirt particles are more easily discharged than they are to enter and accumulate in the recesses, thereby maintaining spray arm reliability.
Solution Approach 2:
The cross-sectional parameters of the recesses are changed along their length, with the outlet cross-section being larger than the inlet cross-section. This parameter change creates a geometric configuration that favors dirt particle discharge over accumulation, resolving the contradiction between dirt removal capability and dirt accumulation prevention.
2Reliability
If bearing gaps are enlarged to prevent blocking, then spray arm movement reliability is improved, but hydraulic leakage increases
Solution Approach 1:
The bearing section is designed with localized expanding recesses that provide dirt removal functionality only where needed, while the rest of the bearing structure maintains tight tolerances to prevent washing liquid leakage. This local differentiation of quality allows the system to achieve both reliability and substance conservation.
Solution Approach 2:
The bearing section is segmented into functional zones: expanding recesses for dirt particle discharge and controlled gap regions for maintaining hydraulic integrity. This segmentation allows different parts of the bearing structure to serve different functions, preventing both blockage and excessive leakage.
3Device complexity
If smaller spray arms with shorter length are used, then device complexity and space requirements are reduced, but drive torque decreases making blocking more frequent
Solution Approach 1:
The expanding recesses in the bearing sections provide a self-cleaning mechanism that automatically flushes dirt particles from the bearing areas during operation. This self-service functionality compensates for the reduced drive torque in smaller spray arms, maintaining rotation reliability without increasing device complexity.
Solution Approach 2:
The hydraulic flow through the expanding recesses creates a self-cleaning effect that removes dirt particles from bearing surfaces. This hydraulic self-service mechanism ensures reliable rotation in compact spray arms by preventing dirt accumulation that would otherwise cause blocking despite reduced drive torque.
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 prevents blockages and maintains cleaning performance by ensuring dirt is flushed out, reducing bearing friction and increasing dirt tolerance without altering the hydraulic cross-section or pressure drop.
Implementation Method 1
a (small) part of the flushing liquid is also pressed through the bearing points (i.e. the gaps present here), which means that a corresponding lubrication can be achieved
Implementation Method 2
The cleaning nozzles are designed to emit spray jets when flushing water under pressure is supplied
Implementation Method 3
the nozzles are also arranged or aligned in such a way that the recoil that occurs causes a rotary movement of the spray arm in question
Implementation Method 4
the recoil that occurs causes a rotary movement of the spray arm in question
Implementation Method 5
the recoil that occurs causes a rotary movement of the spray arm
Implementation Method 6
a (small) part of the flushing liquid is also pressed through the bearing points (i.e. the gaps present here), which means that a corresponding lubrication can be achieved
Implementation Method 7
high frictional forces in the rotary bearing, which can cause the spray arm to become blocked
Data Source
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AI summary
The invention relates to a spray arm assembly for a dishwasher (300), in particular a household dishwasher (300), comprising a spray arm (200) and a retaining element (100) for holding the spray arm (200), wherein the spray arm (200) is rotatably mounted on the retaining element (100), wherein at least one bearing section (120) and at least one counter-bearing section (220) are provided for the rotatable mounting, and wherein the bearing section (120) has recesses (122). The recesses (122) of the bearing section (120) have an expanding shape. The invention further relates to a dishwasher (300) with such a spray arm assembly, as well as a retaining element (100) for holding a spray arm (200) of a dishwasher (300).