Three-Part Gearwheel Structure for Lightweight Torque Transmission
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Solution Overview
Problem
Existing gearwheels in vehicle steering systems require a balance between reliable force and torque transmission while aiming for a lighter and more inexpensive structure, which is not effectively achieved with traditional designs.
Innovation Solution
A three-part gearwheel structure comprising a plastic outer toothed rim injection-molded onto a connecting element with a central through-going opening, where the hub element is press-fitted or bonded to prevent displacement, and reinforced with metal structures for stability and interlocking features to enhance load transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional single-piece metal gearwheel structure is used, then reliable force and torque transmission is achieved, but the gearwheel becomes heavier and more expensive
Solution Approach 1:
The gearwheel is divided into three distinct parts: an outer toothed rim made of plastic material, a connecting element with intermediate thickness, and an inner hub element. This segmentation allows each component to be optimized for its specific function while reducing overall weight compared to a solid metal structure.
Solution Approach 2:
The gearwheel combines different materials strategically: plastic material for the outer toothed rim (reducing weight while maintaining gear engagement), metal connecting element with reinforcing structures (providing structural integrity), and metal hub element (ensuring connection stability). This composite approach achieves weight reduction without sacrificing torque transmission capability.
2Weight of moving object
If the material thickness of the connecting element is reduced to decrease weight, then the gearwheel becomes lighter, but structural stability and force transmission capability deteriorate
Solution Approach 1:
The connecting element features non-uniform thickness distribution with reinforcing structures (such as ribs or stiffeners) strategically positioned in areas requiring higher strength. This local reinforcement maintains structural stability and force transmission capability while keeping the overall material thickness and weight minimized.
Solution Approach 2:
Instead of increasing thickness in the radial direction, the connecting element employs reinforcing structures that extend in axial or circumferential directions, adding structural strength through dimensional complexity rather than simple thickness increase.
3Ease of manufacture
If the gearwheel is designed as a multi-part structure to reduce weight and cost, then manufacturing efficiency improves, but the complexity of assembly and connection increases
Solution Approach 1:
The outer toothed rim is injection-molded directly onto the connecting element in an integrated manufacturing process, eliminating separate assembly steps for these two components. The hub element is press-fitted or bonded to the connecting element, creating a semi-permanent connection that simplifies assembly compared to mechanical fasteners.
Solution Approach 2:
The connecting element incorporates interlocking features and reinforcing structures that automatically align and secure the hub element during press-fitting or bonding, eliminating the need for additional alignment tools or complex assembly procedures.
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 configuration results in a lighter, cost-effective gearwheel that maintains structural stability and reliable force transmission, suitable for use in vehicle steering systems, with improved torque transfer and resistance to torsional loads.
Implementation Method 1
The outer toothed rim is made from a plastic material and injection-molded onto the outer edge of the connecting element. In particular, the outer toothed rim can be injection-molded onto and/or around the outer edge of the connecting element. In particular, the outer toothed rim can be injection-molded onto the outer edge of the connecting element by means of a diaphragm gate.
Implementation Method 2
In particular, the hub element is pressed into the through-going opening. Preferably, by virtue of the press-fit connection any relative displacement of the hub element in relation to the connecting element, particularly in the axial direction relative to the central axis of the gearwheel, is prevented or blocked.
Implementation Method 3
Alternatively, or in addition to the pressing-in of the hub element, the hub element can be connected to the connecting element by means of a bonding connection, in particular by means of an adhesion promoter and/or an adhesive material.
Implementation Method 4
The plastic material can be friction-optimized and/or it can have self-lubricating properties.
Implementation Method 5
The plastic material can be friction-optimized and/or it can have self-lubricating properties.
Data Source
AI summary
The invention relates to a gearwheel (1, 11, 31) with a three-part structure consisting of an outer toothed rim (2), a connecting element (3), and a hub element (4). The outer toothed rim (2) has a plurality of teeth (5) and is made of a plastic material injection-molded onto an outer edge (16) of the connecting element (3). The connecting element (3) has a central through-going opening (7) and the hub element (4) is arranged in the said through-going opening (7). To enable a lighter and/or inexpensive structure, the gearwheel (1, 11, 31) is characterized in that the thickness of the connecting element (3) is less than that of the hub element (4), and the connecting element (3) has a plurality of reinforcing structures (17, 24).