Coaxial Fuel Injection Rack Linkage for Lower Shaft Bending
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Solution Overview
Problem
In traditional fuel injection devices, the lateral offset arrangement of the control rack and link lever leads to a significant bending moment on the operating shaft, causing excessive wear and reducing responsiveness and lifespan.
Innovation Solution
The actuator-side connecting part is positioned on the operating shaft, reducing the bending moment applied to the operating unit, and a biasing member is used to bias the link lever, applying load directly along the operating shaft, thereby reducing abrasion and maintaining responsiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the control rack and link lever are arranged laterally offset from the center portion, then the device structure is simplified and easier to manufacture, but a large bending moment is applied to the operating shaft causing excessive wear and reduced lifespan
Solution Approach 1:
The patent repositions the actuator from a lateral offset arrangement to a central arrangement along the axial direction of the operating shaft. This dimensional repositioning aligns the actuator's operating unit with the control rack, eliminating the lateral offset that caused bending moments. The actuator is now positioned such that its operating unit can directly engage with the control rack along the shaft's axis, transforming the load application from eccentric (causing bending) to concentric (axial only).
Solution Approach 2:
The patent employs asymmetric positioning where the actuator is specifically located at the center portion of the device main body while the control rack is positioned axially along the operating shaft. This asymmetric arrangement ensures that the force transmission path is optimized to minimize bending moments while maintaining manufacturing simplicity. The asymmetric placement creates a direct force alignment between the actuator's operating unit and the control rack.
2Reliability
If the actuator is arranged nearby the center portion, then the bending moment on the operating shaft is reduced, but the device complexity increases due to precise alignment requirements
Solution Approach 1:
The patent merges the actuator's operating unit with the control rack assembly by positioning them in direct engagement along the operating shaft's axis. This merging eliminates the need for complex lateral linkages and offset connections. The actuator's operating unit directly interacts with the control rack, combining the force application and motion transmission functions into a single aligned interface, thereby reducing device complexity while improving reliability.
Solution Approach 2:
The patent creates an equipotential force transmission path by aligning the actuator's operating unit with the control rack along the axial direction. This alignment ensures that forces are transmitted uniformly without creating eccentric loads or bending moments. The equipotential arrangement means that the force application point and the control rack engagement point are at the same axial position, eliminating torque and bending stress.
3Productivity
If the operating unit reciprocates along the operating shaft with lateral offset, then the link lever can swing to adjust fuel pressure, but excessive abrasion occurs on the sliding members
Solution Approach 1:
The patent converts the potentially harmful lateral offset arrangement into a beneficial aligned arrangement. By repositioning the actuator centrally along the operating shaft, the design eliminates the harmful bending moments and excessive abrasion that resulted from lateral offset. The aligned configuration transforms the force transmission into a pure axial reciprocating motion, benefiting the sliding members by reducing wear while maintaining the link lever's ability to swing for fuel pressure adjustment.
Solution Approach 2:
The patent changes the geometric parameters of the actuator positioning from a lateral offset configuration to a central axial configuration. This parameter change involves repositioning the actuator along the axial direction of the operating shaft, changing the spatial coordinates of the operating unit's engagement point. The parameter modification eliminates the lateral distance between the force application point and the control rack, thereby reducing bending moments and abrasion on sliding members.
Data Source
AI summary
Provided is a fuel injection device for engines, configured using a technique which can extend service life while good responsiveness is maintained. This fuel injection device for engines is provided with: a control rack supported so as to be slidable in an axial direction and configured so that the amount of fuel delivered under pressure by a fuel pumping mechanism can be adjusted by changing the sliding position of the control rack in the axial direction; an actuator which can move forward and backward an operation section; and a link lever which is supported in a rockable manner by a support shaft and which rocks as the operation section of the actuator moves forward and backward, thereby sliding the control rack. The fuel injection device for engines is further provided with an actuator-side connection section for connecting the operation section of the actuator to the link lever. The actuator-side connection section is disposed coaxially with the operation section of the actuator.