Balancer Shaft Housing Structure for Stable Oil Pump Gear Mesh
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Solution Overview
Problem
Conventional balancer devices for internal combustion engines experience gear mesh noise due to vibrations from balancer weights, causing instability in the mesh state between the reduction gear and the pump driving gear of the oil pump.
Innovation Solution
A balancer device design featuring a pump mounting fixing part on the lower housing member, a gear accommodating part for the reduction and pump driving gears, and a rigidity-reinforcing part extending along the balancer shafts to stabilize the oil pump and maintain smooth gear mesh, with the rigidity-reinforcing part formed integrally with the pump mounting fixing part.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the oil pump is fixed by bolts at a position adjacent to the balancer device, then the oil pump can be mounted, but the mesh state of the reduction gear and pump driving gear varies due to vibrations, resulting in large gear mesh noise
Solution Approach 1:
The pump mounting fixing part and rigidity-reinforcing part are made integral with each other, forming a unified structure that combines mounting functionality with vibration resistance. This merged structure prevents relative movement between the oil pump and housing, stabilizing the gear mesh state and reducing gear mesh noise.
Solution Approach 2:
The rigidity-reinforcing part extends in the direction of extension of the balancer shafts, creating a structural configuration that resists vibrations in the critical direction. This directional reinforcement stabilizes the gear mesh by preventing vibration-induced displacement of the gear components.
2Ease of manufacture
If the pump section is left in a free state without being fixed to another structural member, then assembly is simplified, but the mesh state varies due to vibrations from balancer weights
Solution Approach 1:
The integral structure of the pump mounting fixing part and rigidity-reinforcing part provides stable gear mesh without requiring additional separate reinforcement components. This merged design maintains assembly simplicity while ensuring vibration resistance and mesh stability.
Solution Approach 2:
The rigidity-reinforcing part is strategically positioned and shaped to provide localized reinforcement where needed for gear mesh stability, while the rest of the structure remains simple. The reinforcement extends in the direction of the balancer shafts to specifically address vibration issues in the gear meshing region.
Data Source
AI summary
Disclosed is a balancer device for an internal combustion engine, wherein: a pump mounting fixing part to which an oil pump is fixed is formed on an end surface of a lower housing member; a gear accommodation part in which a pump driving gear and a reduction gear are accommodated is provided between the oil pump and the pump mounting fixing part; a rigidity-reinforcing part in which an oil discharge passage is defined in communication with a discharge port of the oil pump is formed on the lower housing member so as to extend in a direction of extension of first and second balancer shafts on an outer side of the lower housing member; and a portion of the pump mounting fixing part formed on the end surface of the lower housing member and the rigidity-reinforcing part are made integral with each other.