Camshaft Tool Accommodation Surfaces for Assembly Torque Management
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Solution Overview
Problem
The existing camshaft assembly process is prone to inaccuracy and torsion due to the transmission of tightening torque along the entire length of the inner shaft, leading to potential jamming and increased angular range during fastening, which affects the secure holding of functional elements and the phase adjuster.
Innovation Solution
The introduction of tool accommodation surfaces on the cylindrical surface of second functional elements, such as cams or a sensor wheel, allows for the distribution and absorption of torques during fastening, reducing the twisted length of the inner shaft and enhancing the accuracy and reproducibility of the assembly process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the central screw is used to fasten the phase adjuster to the inner shaft, then the phase adjuster is securely fastened, but the entire inner shaft is twisted to a considerable extent due to torque transmission over its entire length
Solution Approach 1:
The patent divides the torque transmission path into segments by introducing intermediate bearing elements (such as bearing rings or roller bearings) between the phase adjuster and the inner shaft. These bearing elements are arranged at different axial positions along the inner shaft, creating multiple support points that segment the shaft into shorter sections, thereby reducing the torsional deformation in each segment while maintaining secure fastening.
Solution Approach 2:
The patent introduces bearing elements as intermediary components between the phase adjuster and the inner shaft. These bearing elements serve as mediators that support the phase adjuster and transmit torque locally without requiring the entire inner shaft to bear the full torque load, thus reducing overall shaft torsion and improving assembly precision.
2Ease of manufacture
If the inner shaft is held securely against the opposite end during tightening, then the phase adjuster can be fastened with preset tightening torque, but the torsion of the entire inner shaft leads to a lengthening of the angular range covered during tightening
Solution Approach 1:
By segmenting the torque transmission path through intermediate bearing elements, the patent reduces the effective torque transmission length of the inner shaft. This segmentation allows the tightening process to cover a smaller angular range since the torque is distributed over shorter shaft sections, thereby reducing the time required for tightening while maintaining process control.
3Reliability
If friction or jamming occurs during tightening, then the total applied torque may not actually act on the screw connection, but providing additional holding mechanisms increases device complexity
Solution Approach 1:
The bearing elements act as intermediary components that provide reliable torque transmission paths. By distributing the torque load through multiple bearing elements at different axial positions, the patent ensures that torque is reliably transmitted to the screw connection without relying solely on friction or complex holding mechanisms, thus maintaining reliability while avoiding excessive complexity.
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 ensures that the torques are effectively managed, preventing jamming and improving the secure fastening of the phase adjuster to the inner shaft, thereby increasing the accuracy and reliability of the assembly process.
Implementation Method 1
a phase adjuster connected to the outer shaft and the inner shaft for rotating the inner shaft relative to the outer shaft, wherein the phase adjuster is fastened to the inner shaft thereby applying a torque
Implementation Method 2
The screwing usually takes place by means of a central screw, which in the fixed state lies adjacent to an end face of the phase adjuster and engages in an accommodation of the inner shaft. In order to be able to fasten the rotor to the inner shaft by means of the central screw with a preset tightening torque, a holding torque directed opposite to the tightening torque has to be applied
Implementation Method 3
The drawback arises here that the tightening torque is transmitted over the entire length of the inner shaft, which is correspondingly twisted to a considerable extent. Depending on the length of the inner shaft, this torsion may be so great that the cams or other functional elements lying remote from the phase adjuster and being fastened to the inner shaft strike against an end position
Implementation Method 4
Friction or jamming may mean that the total applied torque does not actually act on the screw connection
Data Source
AI summary
The invention relates to a camshaft, in particular for motor vehicle engines, comprising an outer shaft (1), an inner shaft (2) arranged coaxially in the outer shaft (1), first functional elements (3) rigidly arranged on the outer shaft (1), second functional elements (4a, 4b), which are rotatably arranged on the outer shaft (1) and fastened to the inner shaft (2) in a rotationally fixed manner, and a phase adjuster (5) connected to the outer shaft (1) and the inner shaft (2) for rotating the inner shaft (2) relative to the outer shaft (1), wherein the phase adjuster (5) is fastened to the inner shaft (2) and thereby a torque is applied. According to the invention, one of the functional elements (4a, 4b) connected to the inner shaft (2) in a rotationally fixed manner has tool accommodation surfaces (11) on the cylindrical surface side outside of a functional surface (12a, 12b). The invention further relates to such a functional element.