Valve Shaft Press-Fit Geometry for Precise Gear Alignment
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Solution Overview
Problem
Existing valve devices for motor vehicles experience rotational angle deviations due to frictional forces when using nuts to fix the gear arrangement, leading to inconsistent fluid flow rate control.
Innovation Solution
A valve device with a metal shaft and resin gear unit, where the shaft end section has a press-fitted configuration with flat and curved surfaces, and the receiving hole has corresponding flat and curved surfaces, allowing for precise alignment and reduced frictional forces, ensuring accurate rotational angle maintenance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If nuts are used to fix the gear arrangement to the shaft, then the gear can be securely attached, but rotational angle deviations occur due to frictional forces
Solution Approach 1:
The invention extracts the nut fastening mechanism from the connection between the gear arrangement and shaft, replacing it with a press-fit configuration where the shaft is directly inserted into the gear unit. This eliminates the nut entirely, removing the source of frictional forces that caused rotational angle deviations while maintaining secure attachment through the press-fit interface.
Solution Approach 2:
The invention introduces a resin-based gear unit as an intermediary component between the metal shaft and the gear arrangement. This resin gear unit features a receiving hole that accepts the shaft end section, creating a friction-fit connection that eliminates the need for nuts. The resin material provides sufficient holding strength while minimizing frictional forces that would otherwise cause rotational angle deviations.
2Manufacturing precision
If a press-fitted configuration is used between the shaft and gear unit, then rotational deviations are minimized, but manufacturing precision requirements increase
Solution Approach 1:
The invention changes the material parameter of the gear unit from traditional metal to resin, which fundamentally alters the connection mechanism. The resin material allows for a press-fit configuration where the shaft is inserted into a receiving hole with slightly smaller diameter, creating a friction-fit connection. This parameter change enables precise rotational angle maintenance through the interference fit while simplifying assembly, as the press-fit connection is achieved through simple insertion rather than complex fastening operations.
3Object-generated harmful factors
If the shaft is made of metal and gear unit is made of resin, then rotational friction is reduced, but material compatibility challenges arise
Solution Approach 1:
The invention employs a composite material configuration where a metal shaft is inserted into a resin gear unit. The metal shaft provides structural strength and rotational stability, while the resin gear unit provides a compliant receiving hole that minimizes frictional forces during rotation. This composite approach leverages the complementary properties of both materials: the metal's rigidity and the resin's lower friction characteristics, creating an effective connection that reduces rotational friction while maintaining structural integrity.
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 press-fitted configuration minimizes rotational deviations and facilitates easier rotation of the shaft, ensuring precise control over fluid flow rates and reducing the risk of gear arrangement misalignment.
Implementation Method 1
The press-fitted configuration minimizes rotational deviations and facilitates easier rotation of the shaft, ensuring precise control over fluid flow rates and reducing the risk of gear arrangement misalignment
Data Source
AI summary
A shaft end section of a shaft is inserted into a receiving hole of a shaft receiver of a gear arrangement. An outer periphery, which forms an outer periphery of the shaft end section, has an end section flat surface portion and an end section curved surface portion. A receiving hole inner periphery, which forms an inner periphery of the receiving hole, has a receiving hole flat surface portion and a receiving hole curved surface portion. The shaft end section is press-fitted such that the receiving hole flat surface portion contacts at least a part of the end section flat surface portion, and the receiving hole curved surface portion contacts at least a part of the end section curved surface portion, while a central axis of the shaft end section overlaps with a central axis of the receiving hole.