Variable Valve Mechanism Sliding Roller Friction Reduction
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Solution Overview
Problem
Existing variable valve mechanisms for internal combustion engines suffer from transmission loss in displacement of the cam due to friction and deformation, requiring excessive lubrication and leading to errors in valve operation.
Innovation Solution
A variable valve mechanism that employs a rolling roller member with a fixed inner ring and outer ring, along with a sliding roller member, to reduce friction and deformation, while using a guide part to maintain the posture of the transmission member and conserve lubrication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a needle roller member is used in the contact part between cam and center rocker arm, then friction is reduced, but the roller member deforms under load causing transmission loss
Solution Approach 1:
The invention extracts the function of reducing friction from the needle roller member and implements it through a sliding bearing mechanism instead. The sliding roller member with inner ring and outer ring separates the friction-reducing function from the load-bearing function, allowing the contact surface to slide smoothly while maintaining structural integrity under load.
Solution Approach 2:
The invention changes the contact mechanism from rolling contact (needle roller) to sliding contact (sliding bearing). This parameter change in the type of contact transforms the friction characteristics while improving load distribution and reducing deformation under operational loads.
2Ease of operation
If multiple transmission components are used to transmit cam displacement, then valve operation is controlled, but friction and deformation cause transmission loss
Solution Approach 1:
The sliding roller member acts as an intermediary between the cam and the swing cam, providing a smooth transmission interface. The inner ring and outer ring structure mediates the force transmission while minimizing friction and deformation, ensuring accurate displacement transfer.
Solution Approach 2:
The transmission member is segmented into an inner ring and an outer ring, allowing independent optimization of each component. The inner ring contacts the cam while the outer ring contacts the swing cam, enabling precise control of valve operation with reduced transmission loss.
3Force
If sliding contact is used between center rocker arm and swing cam, then friction is generated requiring excessive lubrication, but lubrication needs increase
Solution Approach 1:
The sliding bearing mechanism is designed to distribute lubrication automatically through its structure. The inner ring and outer ring configuration creates natural lubrication pathways that reduce the overall quantity of lubrication required while maintaining effective friction reduction.
4Power
If the contact part is designed for load transmission, then displacement is transmitted, but deformation occurs reducing transmission accuracy
Solution Approach 1:
The invention changes the contact mechanism from rolling to sliding, which alters the stress distribution parameters. The sliding contact surface distributes loads more evenly, reducing peak stresses and preventing deformation that would compromise transmission accuracy.
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 solution effectively suppresses transmission loss and friction, reduces lubrication needs, and maintains accurate displacement transmission to the valves, enhancing engine efficiency and operation.
Implementation Method 1
a sliding roller member which receives the displacement of the cam in a state that the outer peripheral surface is in rolling contact with the cam
Implementation Method 2
a sliding bearing mechanism is constituted between the sliding roller member and the support part
Data Source
Figure 1
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AI summary
A variable valve mechanism for an internal combustion engine includes a rocker arm (61, 361), a swing cam (64, 364), and a transmission member (62, 362) which is interposed between the swing cam (64, 364) and a cam (51a, 51b, 351a, 351b) and transmits the displacement of the cam (51a, 51b, 351a, 351b) to the swing cam (64, 364). The rocker arm (61, 361) is provided with a rolling roller member (66, 366) which includes a inner ring (66b, 366b), an outer ring (66a, 366a), and a plurality of rolling elements (66c, 366c) accommodated between the inner ring (66b, 366b) and the outer ring (66a, 366a). The outer ring (66a, 366a) contacts with the swing cam (64, 364). At least one of a first transmission part (91, 391), in which the displacement of the cam (51a, 51b, 351a, 351b) is transmitted from the cam (51a, 51b, 351a, 351b) to the transmission member (62, 362), and a second transmission part (92, 392), in which the displacement of the cam (51a, 51b, 351a, 351b) is transmitted from the transmission member (62, 362) to the swing cam (64, 364), includes a sliding roller member (67, 90, 367, 390), wherein a sliding bearing mechanism is constituted between the sliding roller member (67, 90, 367, 390) and the support part (64g, 69a, 364g, 369a).