Engine Balancer Piston Curved Contact Geometry
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Solution Overview
Problem
The existing engine balancer systems face difficulties in easy installation and noise reduction due to the complex component arrangement and impact issues caused by the balancer piston's interaction with the cylinder wall, particularly when using a joint pin attachment method.
Innovation Solution
A balancer piston is fixed to the rod using a screw, allowing easier installation and featuring a curved outer peripheral portion that reduces impact by coming into contact with the cylinder wall before significant acceleration occurs, minimizing noise through optimized clearance and contact geometry.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a joint pin is used to attach the balancer piston to the rod, then the balancer piston can pivot freely, but the component arrangement becomes complicated and installation becomes difficult
Solution Approach 1:
The invention extracts the pivoting function from a separate joint pin component and integrates it into the rod structure itself. The rod is designed with a tilted engagement surface that inherently provides the pivoting capability, eliminating the need for a distinct joint pin and simplifying the overall component arrangement.
Solution Approach 2:
The invention merges the pivoting function with the rod structure by creating an integrated engagement mechanism. The balancer piston engages with the rod through a tilted surface that combines both connection and pivoting functions in a single structural feature, reducing the number of separate components.
2Adaptability or versatility
If a joint pin is used to attach the balancer piston to the rod, then the balancer piston can pivot freely, but installation becomes troublesome when the balancer piston is inside the cylinder
Solution Approach 1:
The invention applies preliminary action by designing the rod with a pre-formed tilted engagement surface that guides the balancer piston into the correct pivoting position during installation. This preliminary structural feature ensures proper alignment and pivoting capability are established automatically when the piston is installed from the cylinder opening.
3Ease of operation
If the balancer piston is rigidly fixed to the rod, then installation is easier, but the piston tilts with the rod causing repeated contact and separation from the cylinder wall
Solution Approach 1:
The invention applies dynamics by allowing the balancer piston to pivot dynamically relative to the rod through the tilted engagement surface. This dynamic adjustment enables the piston to maintain optimal contact with the cylinder wall during rod reciprocation, preventing repeated impact and separation while still being firmly attached.
4Ease of operation
If the clearance between the rigid balancer piston and cylinder wall is large, then installation is easier, but the acceleration increases causing great impact and noise
Solution Approach 1:
The invention changes the geometric parameters of the engagement interface by introducing a tilted surface with a specific angle. This parameter change allows the balancer piston to maintain a smaller, optimized clearance that reduces impact and noise while still accommodating manufacturing tolerances and enabling proper installation.
Data Source
AI summary
A balancer of an engine includes a rod and a balancer piston. A first end portion of the rod includes a joining portion which is arranged to be joined to a crankshaft of the engine at a position that is eccentric relative to a rotation axis of the crankshaft. A second end portion of the rod is arranged to reciprocate inside a cylinder according to a rotation of the crankshaft. The balancer piston is fixed to the second end portion of the rod. The balancer piston is arranged to reciprocate inside the cylinder, while rocking between a contact state in which the balancer piston is in contact with an inner wall surface of the cylinder and a non-contact state in which the balancer piston is separated from the inner wall surface. The balancer piston includes a cylindrical outer peripheral portion that is curved so as to swell toward the inner wall surface. The outer peripheral portion is arranged such that lines of intersection with planes perpendicular or substantially perpendicular to a central axis of the balancer piston define circles. The outer peripheral portion includes a contact start portion which is arranged to come into contact first with the inner wall surface when the balancer piston switches from the non-contact state to the contact state. A distance from a center of a maximum outer diameter circle with the largest radius among the circles to the contact start portion is larger than the radius of the maximum outer diameter circle.