Silent Chain Pin Hole Geometry for Vibration Suppression
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Solution Overview
Problem
Conventional silent chains face challenges in suppressing vibration and undulation while maintaining rigidity, strength, and durability, especially under high load conditions, due to the need for special locker pins and complex pin hole designs that increase production costs and introduce additional vibration risks.
Innovation Solution
A silent chain design featuring pin holes with outer and inner peripheral side straight portions formed in flat surface shapes, parallel to each other, which restrict locker pin movement during bending, allowing for ordinary locker pins and materials, simplifying the pin hole shape and maintaining rigidity, strength, and durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If restricting members such as chain guides or tensioners are provided to suppress vibration and undulation, then vibration and undulation in free span are suppressed, but sliding resistance and contact noise increase
Solution Approach 1:
The silent chain structure itself provides vibration suppression through the elastic deformation of locker pins within pin holes, eliminating the need for external restricting members. The pin holes are designed with specific geometric features (straight portions on inner and outer peripheral sides) that enable the locker pins to elastically deform and restrict chain bending, making the system self-regulating without additional components that would generate friction or noise.
Solution Approach 2:
The function of external restricting members (chain guides, tensioners) is extracted and integrated into the silent chain's own structure through the specially designed pin holes. The pin holes contain straight portions that directly restrict locker pin movement during bending, transferring the vibration suppression function from external components to the chain's intrinsic structure, thereby eliminating contact noise and sliding resistance associated with external restrictors.
2Stability of the object's composition
If locker pins are made of materials with low rigidity to enable elastic deformation for bending restriction, then vibration and undulation are suppressed, but rigidity, strength and durability under high load decrease
Solution Approach 1:
The pin hole structure incorporates localized straight portions on its inner and outer peripheral sides, creating specific zones that guide and restrict locker pin movement during bending. This local geometric modification enables elastic deformation exactly where needed (in the pin hole-pin interface region) while the bulk material of the locker pin maintains its high rigidity and strength properties, allowing the component to satisfy both flexibility for vibration suppression and strength for load-bearing requirements.
Solution Approach 2:
The invention changes the geometric parameters of the pin hole rather than the material properties of the locker pin. By designing pin holes with specific straight portions at defined positions and dimensions, the system achieves controlled elastic deformation during bending while preserving the locker pin's material strength and rigidity for withstanding high loads, thus resolving the contradiction between flexibility and strength through parameter optimization.
3Stability of the object's composition
If pin holes are designed with complex shapes including position restricting surfaces and bending restricting portions, then relative positions are fixed and bending is restricted, but manufacturing complexity and production cost increase
Solution Approach 1:
The pin hole is segmented into distinct functional zones: straight portions located on the inner peripheral side and outer peripheral side, each serving specific functions in restricting locker pin movement during bending. This segmentation into clearly defined geometric regions simplifies the manufacturing process compared to complex continuous surfaces, as each straight portion can be independently formed and controlled, reducing manufacturing complexity while maintaining effective bending restriction.
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 suppresses vibration and undulation without the need for special locker pins or materials, ensuring reliable performance under high load conditions while reducing production costs and maintaining dimensional accuracy.
Implementation Method 1
the pair of front and rear pin holes of at least one of the middle plate and the inner plates has an outer peripheral side straight portion and an inner peripheral side straight portion, the outer peripheral side straight portion is formed in a flat surface shape that restricts, when being bent in a forward direction, movement of the locker pins toward an outer circumferential side of the bending, the inner peripheral side straight portion is formed in a flat surface shape that restricts, when being bent in a backward direction, movement of the locker pins toward an inner circumferential side of the bending
Data Source
AI summary
An object of the present invention is to provide a silent chain which suppresses vibration and undulation while maintaining rigidity, strength, and durability and simplifying a shape of a pin hole without using a locker pin with a special shape and special material. In a silent chain 100, a guide row 101 made up of guide plates 110 and a middle plate 120 and a non-guide row made 103 made up of inner plates 130 are alternately connected in a chain longitudinal direction by a pair of locker pins 140 and 150. Pin holes 121 and 131 respectively have outer peripheral side straight portions 123 and 133 and inner peripheral side straight portions 124 and 134 which are formed parallel to each other.