Blind Hole Fastening Geometry for High Holding Force
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Solution Overview
Problem
Existing fastening methods for components to base elements with blind holes struggle to achieve high holding forces due to limited blind hole depth and effective fastening element length, especially in plate-shaped base elements where drilling through is not feasible.
Innovation Solution
A method involving the production of a blind hole with a frustoconical force transmission surface and a conical bottom, optimized by controlling the cone opening angles and chamfer depth to maximize the surface area for force transmission, allowing for a fastening element to be anchored in a form-fitting manner, thereby enhancing holding force.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a sufficiently deep hole is drilled and a correspondingly long fastener is used to achieve maximum holding force, then the holding force is improved, but the base element thickness requirement increases and drilling time increases
Solution Approach 1:
The invention changes the geometric parameters of the blind hole, specifically creating a conical base with a specific cone opening angle (α) between 90° and 120°, and optimizing the chamfer depth (L) between 0.1 mm and 0.5 mm. This parameter optimization allows the force transmission surface area to be maximized within a limited depth (T < 10 mm), achieving high holding force without requiring increased base element thickness
Solution Approach 2:
The invention transitions from a conventional cylindrical blind hole to a conical blind hole with an optimized force transmission surface. By changing the dimensional geometry from straight-walled to conical, the surface area for force transmission is significantly increased within the same depth constraint, enabling high holding force in thin base elements
2Strength
If a sufficiently deep hole is drilled and a correspondingly long fastener is used to achieve maximum holding force, then the holding force is improved, but the drilling time increases
Solution Approach 1:
By optimizing the blind hole depth (T < 10 mm) and creating a conical base geometry with specific angles, the invention reduces the required drilling depth while maintaining high holding force. This parameter optimization directly reduces drilling time without sacrificing anchoring strength
Solution Approach 2:
The invention creates a conical base that extends beyond the immediate force transmission surface, with the cone opening angle (α) optimized to provide both sufficient anchoring area and reduced depth requirement. This partial conical extension provides excessive geometric support that compensates for the reduced depth, achieving high holding force in less time
3Length of stationary object
If the blind hole depth is limited in plate-shaped base elements, then the base element thickness is reduced, but the holding force decreases
Solution Approach 1:
The invention optimizes multiple parameters simultaneously: cone opening angle (α) between 90° and 120°, chamfer depth (L) between 0.1 mm and 0.5 mm, and force transmission surface area (A). These parameter changes enable the creation of a high-strength anchoring geometry within limited depth (T < 10 mm), achieving high holding force in thin base elements
Solution Approach 2:
By transforming the blind hole geometry from cylindrical to conical with an optimized force transmission surface, the invention increases the effective anchoring surface area within the limited thickness. This dimensional change allows thin base elements to achieve high holding force through optimized surface geometry rather than increased depth
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 method ensures a high holding force for the fastening element within the given blind hole depth, effectively utilizing the available depth for force transmission, even in base elements with limited thickness, by optimizing the geometry of the blind hole and fastening element interaction.
Implementation Method 1
a frustoconical force transmission surface (220), which has a surface area A and a mean diameter d, into which a fastening element (130) is anchored in a form-fitting manner
Implementation Method 2
The blind hole (110) has a conical base (120) with a cone opening angle α and has a chamfer (230) at its edge
Data Source
Figure 1~2
AI summary
A method for fastening a component (190) to a base element (100), in which method there is produced in the base element (100) a blind bore (110) which defines a depth direction (160) and which has a force transmission surface (220) which has a depth T in the depth direction (160), wherein the force transmission surface (220) is of frustoconical form with a cone opening half-angle (β) and a mean diameter (d), wherein the blind bore (110) has a conical blind bore base (120) with a cone opening angle (α) and, at the edge thereof, a bevel (230) which extends in the depth direction (160) to a bevel depth L, wherein, in the method, a fastening element (130) is anchored in the blind bore (110) by way of the force transmission surface (220), and wherein the component (190) is held by the fastening element (130).