Vacuum Pump Mounting Structure for Engine Vibration Control
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Solution Overview
Problem
Existing vacuum pump mounting structures fail to effectively suppress vibration and noise in engines due to the floating of cam housings caused by the cam shaft, leading to increased engine vibration and noise.
Innovation Solution
A vacuum pump mounting structure where the vacuum pump is fixed to both the cam housing and cylinder head using boss portions, with a detachable cover to block noise and a timing gear configuration that avoids interference, ensuring the pump is securely attached and reduces engine vibration and noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the vacuum pump body is simply attached to the cover, then the structure is simple and easy to manufacture, but the cam housing floats due to force from the cam shaft, causing vibration and noise
Solution Approach 1:
The vacuum pump body is merged with both the cam housing and cylinder head through fixed connections at multiple locations. This combining of mounting points eliminates the floating issue while maintaining manufacturing simplicity by using the existing structural components as mounting bases.
Solution Approach 2:
The cam housing is preliminarily secured to the cylinder head through fixed connections before the vacuum pump is mounted. This preliminary securing action prevents the cam housing from floating during operation, thereby eliminating vibration and noise before they can occur.
2Object-affected harmful factors
If the vacuum pump body is fixed to both cam housing and cylinder head, then floating of cam housing is suppressed and vibration noise is reduced, but the device complexity increases
Solution Approach 1:
The mounting structure is segmented into multiple fixed connection points: one between the cam housing and cylinder head, and another between the vacuum pump body and these components. This segmentation allows the system to achieve stability through distributed fixed connections rather than a single complex mounting mechanism.
Solution Approach 2:
The vacuum pump body serves multiple functions: it houses the vacuum pump mechanism and simultaneously acts as a structural component that fixes the cam housing to the cylinder head. This multi-functionality reduces the need for additional separate mounting structures, thereby limiting the increase in device complexity.
3Device complexity
If the vacuum pump is mounted on the cover, then the mounting structure is simple, but it is not possible to suppress the vibration and noise from the floating cam housing
Solution Approach 1:
The vacuum pump body acts as an intermediary component that connects and secures the cam housing to the cylinder head. This intermediary mounting structure eliminates the floating issue by providing a fixed connection path, while still maintaining relative simplicity by utilizing the vacuum pump body as the mounting interface.
Data Source
AI summary
There is provided a vacuum pump mounting structure. A vacuum pump is connected to an axial end portion of a first cam shaft of an engine and is configured to be driven by the first cam shaft. The first cam shaft is disposed in a cylinder head. A cam housing rotatably supports the first cam shaft on the cylinder head. A cam housing-side boss portion and a cylinder head-side boss portion are formed in the cam housing. An engine-upper side of a body portion of the vacuum pump is fixed to the cam housing-side boss portion. An engine-lower side of the body portion of the vacuum pump is fixed to the cylinder head-side boss portion.