Stud Bolt Support Structure for Housing Crack Reduction
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Solution Overview
Problem
Existing stud bolts in working devices, such as chainsaws, transmit both longitudinal and transverse forces through the same threaded connection, leading to stress on the housing and potential cracking, especially with long guide rails.
Innovation Solution
The stud bolt design separates the transmission of longitudinal and transverse forces by positioning a support area for transverse force transmission at a distance from the threaded connection, reducing stress on the internal thread of the housing and minimizing the risk of cracking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the stud bolt transmits both longitudinal and transverse forces through the same threaded connection, then the stud bolt can be securely fastened to the housing, but the internal thread of the housing experiences stress leading to potential cracking
Solution Approach 1:
The stud bolt is divided into functionally distinct sections: a first section with external thread for longitudinal force transmission, and a second section with a support region for transverse force transmission. This segmentation separates the two force transmission paths, allowing each to be optimized independently and preventing stress concentration in the housing's internal thread.
Solution Approach 2:
The support region for transverse forces is positioned at a distance from the threaded connection in the axial direction, utilizing the third dimension (axial spacing) to separate the force transmission zones. This spatial separation allows transverse forces to be transmitted to the housing without passing through the internal thread, thereby protecting the thread from cracking while maintaining secure fastening.
2Device complexity
If the support area for transverse forces is positioned close to the threaded connection, then the stud bolt structure is compact, but the internal thread experiences high stress and cracking risk increases
Solution Approach 1:
By utilizing axial spacing (a dimension perpendicular to the force application plane), the design achieves separation of force transmission zones without significantly increasing overall structural footprint. The support region is positioned at a controlled distance from the threaded connection, optimizing the balance between compactness and crack resistance.
3Device complexity
If the external thread and internal thread overlap in the axial direction, then the threaded connection is compact, but transverse forces are transmitted through the thread causing stress concentration
Solution Approach 1:
The stud bolt is segmented into a first section containing the external thread and a second section containing the support region. This segmentation ensures that the support region for transverse forces does not overlap axially with the external thread, allowing transverse forces to be transmitted to the housing without passing through the threaded connection, thereby eliminating stress concentration in the threads.
Solution Approach 2:
The function of transverse force transmission is extracted from the threaded connection and assigned to a separate support region. This extraction allows the threaded connection to be optimized solely for longitudinal force transmission, while transverse forces are handled by the support region positioned at a distance, preventing stress concentration in the threads.
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
The invention relates to a working device comprising a housing part (2) and a stud bolt (3) for attaching a tool (4) to the housing part (2). The stud bolt (3) extends along an axial direction (100). The stud bolt (3) has a first section (10) and a second section (20) in the axial direction (100). The axial direction (100) runs from the first section (10) to the second section (20). The first section (10) is at least partially arranged in a receptacle (5) of the housing part (2). The second section (20) projects from the housing part (2) in the axial direction (100). The first section (10) of the stud bolt (3) has an external thread (13) in a first subsection (11) which is screwed into an internal thread (31) of the receptacle (5) of the housing part (2) for the transmission of axial forces (L).The first section (10) of the stud bolt (3) has a support area (15) in a second subsection (12) for transmitting lateral forces (Q) to the housing part (2), which is supported at least indirectly on the receptacle (5). The support area (15) is arranged in the axial direction (100) at a distance (a1) from the threaded connection (40) of the external thread (13) and internal thread (31).