Valve Timing Adjuster Knock Pin Alignment
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Solution Overview
Problem
Existing valve timing adjusting devices face challenges in maintaining precise phase control between the crankshaft and camshaft due to clearance issues and positional deviations, which can lead to difficulties in controlling the open/close timing of intake and exhaust valves, especially during engine start-up when the vane rotor may collide with the oil chamber walls.
Innovation Solution
A valve timing adjusting device design that includes a sprocket, a vane rotor, a housing with an oil chamber, and a knock pin, where the knock pin abuts against specific inner walls of the sprocket and housing holes to prevent positional deviations, and a manufacturing apparatus that ensures precise alignment and clamping of the sprocket and housing using pushers and jigs to eliminate clearance and ensure correct phase control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If there is clearance between the knock pin and the inner walls of the sprocket and housing holes, then assembly is easier and manufacturing tolerance is accommodated, but positional deviation occurs between the sprocket and housing during engine start, causing the fixing bolt to loosen
Solution Approach 1:
The knock pin is designed to preliminarily abut against the inner walls of the sprocket and housing holes before the bolt is tightened. This preliminary action prevents positional deviation during engine start by establishing proper alignment in advance, while still allowing for manufacturing tolerances in the hole and pin dimensions.
2Adaptability or versatility
If the vane rotor is at the intermediate phase position during engine stop, then the valve timing adjustment is flexible, but rapid oil flow into the oil chamber during engine start causes collision between the vane rotor and the inner wall of the oil chamber, leading to positional deviation
Solution Approach 1:
The knock pin performs a preliminary abutment action against the sprocket and housing inner walls during engine start, establishing proper alignment before the vane rotor begins to move. This prevents the vane rotor from colliding with the oil chamber inner wall and maintains phase control accuracy while allowing flexible valve timing adjustment during normal operation.
3Ease of manufacture
If the knock pin is inserted into the sprocket and housing holes without precise alignment, then assembly is simpler and manufacturing is easier, but the fixing bolt cannot properly secure the sprocket and housing together
Solution Approach 1:
The knock pin is designed to perform a preliminary alignment action by abutting against the inner walls of the sprocket and housing holes. This preliminary action ensures proper alignment before the bolt is tightened, allowing for simpler assembly while achieving the necessary alignment precision through the geometric relationship between the knock pin and the hole inner walls.
Data Source
AI summary
A valve timing adjusting device for and engine includes a sprocket configured to rotate by receiving drive power from a driving shaft, a vane rotor fixed to a driven shaft so as to be rotatable relative to the sprocket, a housing that includes an oil chamber housing the vane rotor and is fixed to one end in a thickness direction of the sprocket, a bolt fixing the sprocket to the housing, and a knock pin inserted into a sprocket hole formed in the sprocket at one end thereof and into a housing hole formed in the housing at the other end thereof to restrict relative relation between the sprocket and the housing. The knock pin abuts against an inner wall of the sprocket hole at one end thereof, and abuts against an inner wall of the housing hole at the other end thereof.