Parking Brake Locking Apparatus with Recessed Spring Arm
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Solution Overview
Problem
Existing locking apparatuses for vehicles with automatic transmissions require large installation space and high manufacturing costs due to the need for high holding forces and bending stiffness, which is not efficiently addressed by previous designs that rely on thick components and complex manufacturing tolerances.
Innovation Solution
A locking apparatus with an axially displaceable piston unit and a catch device featuring a spring arm with a recess in its longitudinal plane, allowing the piston unit to intersect radially, thereby reducing the lever arm and bending moment applied to the spring arm, enabling smaller component dimensions and reduced material use while maintaining effective holding force transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the actuating element is designed as a sprayed-on or clipped-on plastic component with thick walls, then the necessary holding forces are provided, but the installation space requirement increases significantly
Solution Approach 1:
The actuating element is designed as a thin-walled plastic component (wall thickness 0.5-2 mm) that is clipped onto the electromagnet yoke, replacing thick-walled sprayed-on components. This thin-film approach provides sufficient holding force through optimized geometry and material selection while dramatically reducing the installation space requirement.
Solution Approach 2:
The actuating element is segmented into functional zones: a thin-walled body for space efficiency, a clipped-on connection section for secure attachment to the electromagnet, and an engagement section for interaction with the catch element. This segmentation allows each part to be optimized for its specific function, providing high holding force where needed while maintaining overall compactness.
2Force
If the actuating element is designed as a punched component fastened with a tension spring, then the pre-tensioning is increased, but the manufacturing tolerances must be extremely tight to assure functioning
Solution Approach 1:
The actuating element incorporates an integrated connection section with clipping elements that automatically engage with corresponding features on the electromagnet yoke. This self-clipping mechanism eliminates the need for separate tension springs and complex fastening operations, providing reliable pre-tensioning through the elastic deformation of the plastic material itself while being tolerant of normal manufacturing variations.
Solution Approach 2:
The material properties of the actuating element are specifically selected (rigid plastic with controlled elasticity) to provide the necessary pre-tensioning force through its structural design rather than through tight tolerance control. The clipping connection utilizes the material's elastic range to accommodate normal manufacturing tolerances while maintaining sufficient pre-tensioning for reliable operation.
3Force
If the catch elements are dimensioned with high bending stiffness to counteract bending moments in locked condition, then the holding force is maintained, but the component weight and manufacturing costs increase
Solution Approach 1:
Instead of designing the actuating element to resist bending moments through high stiffness (which would increase weight), the invention inverts the approach: the actuating element is designed with low bending stiffness to allow controlled deformation, while the holding force is maintained through the elastic recovery of the material and the geometric configuration of the engagement between the actuating element and catch element.
Solution Approach 2:
The actuating element utilizes thin-walled plastic construction that naturally provides the necessary flexibility to accommodate bending moments during engagement and locking without requiring high bending stiffness. The thin-walled design reduces weight while the elastic properties of the plastic material provide sufficient structural integrity and force transmission for reliable locking operation.
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
The solution allows for a locking apparatus that is more economical, lightweight, and compact, with reduced surface pressure and operating force, enabling the use of lighter materials like aluminum and minimizing manufacturing costs while maintaining reliable locking and unlocking functionality.
Implementation Method 1
the spring arm (5A) is actively connected to a piston unit (4) in the locked position, wherein the piston unit (4) abuts the spring arm (5A) in locked position with a catch area (27)
Data Source
AI summary
A locking apparatus, particularly of a parking brake device for a vehicle with an automatic transmission, which has a piston unit positioned inside a housing and is axially displaced and locked in a pre-defined axial position, and a catch device that automatically activates when the piston unit is locked to hold the piston unit. The catch device has at least one spring arm actively connected with the piston unit when the piston unit is locked, the spring arm abuts the piston unit in locked position with a catch area. The spring arm has a recess in a longitudinal plane of the spring arm. The piston unit penetrates the recess of the spring arm at least approximately in a radial direction with a section that forms the catch area, so that when the piston unit is locked, the catch area within the longitudinal plane of the spring arm.