Flap Device Sealing Against Water Ingress
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Solution Overview
Problem
Existing flap devices for internal combustion engines face issues with correct alignment and water penetration between the flow and actuator housings, leading to shaft jamming and reduced service life, particularly due to thermal expansion and spray water ingress.
Innovation Solution
A flap device design featuring a hollow cylindrical projection on the flow housing with a circumferential groove and a receiving element on the actuator housing, ensuring correct axial alignment and sealing to prevent water penetration, with bearings mounted on both housings for reliable support and heat dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the flow housing and actuator housing are separated and connected via mounting frame and screws, then the device allows modular assembly and disassembly, but correct alignment between housings cannot be guaranteed leading to shaft misalignment and jamming
Solution Approach 1:
The mounting frame is pre-formed with integrated guide elements and positioning features that ensure correct alignment of the actuator housing with the flow housing before final fastening. This preliminary alignment structure prevents shaft misalignment while maintaining modular assembly capabilities.
Solution Approach 2:
The mounting frame acts as an intermediary component between the flow housing and actuator housing, providing a precision-machined interface that ensures accurate alignment. The frame's rigid structure and integrated positioning features mediate the connection to prevent misalignment while allowing modular assembly.
2Device complexity
If the housing connection is open without sealing, then the structure is simple and manufacturing is easy, but splash water penetrates between housings and damages bearings reducing service life
Solution Approach 1:
A flexible sealing lip or membrane is integrated into the mounting frame or housing connection, forming a barrier that prevents splash water from penetrating between the flow housing and actuator housing. The flexible seal maintains water tightness while accommodating minor misalignments and thermal expansion.
Solution Approach 2:
The housing connection employs composite construction with sealed chambers, combining structural components with integrated sealing elements. This composite approach provides both mechanical strength and waterproof protection for the bearings without significantly increasing overall device complexity.
3Volume of moving object
If the shaft is exposed outside the flow housing, then access is easier and installation space is reduced, but the shaft is vulnerable to splash water ingress and thermal expansion causing jamming
Solution Approach 1:
The shaft is nested within a protective bearing housing or sealed chamber that extends from the flow housing into the actuator housing. This nested structure protects the shaft from splash water and thermal effects while maintaining a compact overall design with minimal installation space.
Solution Approach 2:
The shaft operates within a sealed, protected environment created by the integrated housing connection and sealing elements. This inert-protected atmosphere isolates the shaft from harmful external factors including splash water and extreme thermal conditions, preventing jamming and corrosion.
4Ease of operation
If bearings are provided to ensure reliable rotation, then rotation is smooth and misalignment is prevented, but the bearings become vulnerable to splash water damage reducing service life
Solution Approach 1:
Flexible sealing lips or membranes are positioned around the bearing areas and shaft interfaces to create waterproof barriers. These flexible seals protect the bearings from splash water ingress while allowing the bearings to maintain smooth rotation and proper alignment during operation.
Solution Approach 2:
The sealed mounting frame and integrated sealing elements act as intermediary protective barriers between the bearings and the external splash water environment. This intermediary sealing structure preserves bearing service life while maintaining operational smoothness.
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 prevents water and exhaust gas ingress, extends shaft protection, and ensures smooth operation even under thermal stress, enhancing the service life and reducing installation complexity and costs.
Implementation Method 1
a circumferential groove (42) formed on an outer circumference of the projection (40)... the groove (42) prevents splash water from penetrating an interior of the flap device
Implementation Method 2
this connection allows heat to be dissipated from the flap shaft via the actuator housing
Data Source
Figure 1
Figure 2
AI summary
Flap devices for internal combustion engines comprising a flow housing (10) which delimits a flow channel (12), a flap body (14) which is arranged rotatably in the flow channel (12), a shaft (16) on which the flap body (14) is secured, an actuator (28) via which the shaft (16) and the flap body (14) can be rotated in the flow channel (12), and an actuator housing (30) in which the actuator (28) is arranged, are known. According to the invention, in order to create a reliable protection of the flap device against penetration of sprayed water, a projection (40) extending in the direction of the actuator housing (30) is formed on the flow housing (10) and a receiving element (44) extending in the direction of the flow housing (10) is formed on the actuator housing (30), which receiving element abuts radially against the projection (40) of the flow housing (10), wherein a circumferential groove (42) is formed between the projection (40) of the flow housing (10) and the receiving element (44) of the actuator housing (30).