Traction Drive Unit Layout Without Differential Ratio Adjustment
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Solution Overview
Problem
Conventional traction transmissions and drive units are space-intensive and complex, particularly due to the need for a differential transmission for adjusting the transmission ratio, leading to increased costs and complexity.
Innovation Solution
The complementary friction discs are fixedly mounted on a common output shaft, and the spider sleeve is axially displaceable relative to the housing, allowing for adjustment of the transmission ratio through torsional twisting of the spiders, eliminating the need for axial displacement and simplifying the design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional traction transmissions use a differential transmission for adjusting the transmission ratio, then the transmission ratio can be adjusted, but the space requirements and device complexity increase
Solution Approach 1:
The patent extracts and eliminates the differential transmission mechanism from the system. Instead of using a complex differential transmission to adjust the transmission ratio, the invention uses a simpler spider sleeve that can be rotated to directly adjust the spacing between spiders, thereby achieving transmission ratio adjustment without the need for a differential transmission.
Solution Approach 2:
The patent inverts the conventional approach by making the spider sleeve rotatable rather than requiring axial displacement of the spiders. This inversion allows the transmission ratio to be adjusted by rotating the spider sleeve, which changes the spacing between spiders through torsional twisting, eliminating the need for a differential transmission mechanism.
2Adaptability or versatility
If conventional traction transmissions use axial displacement of spiders for adjustment, then the transmission ratio can be changed, but the space requirements increase
Solution Approach 1:
The patent changes the adjustment mechanism from axial displacement (one-dimensional linear motion) to rotational movement (circular motion). The spider sleeve rotates around the central axis, and this rotational movement is converted into radial spacing changes between the spiders through the threaded connection, achieving transmission ratio adjustment in a more space-efficient manner.
Solution Approach 2:
The patent employs a nested structure where the first and second spiders are mounted on the spider sleeve in a compact arrangement. The spiders are positioned radially outward from the central axis, allowing them to be closely spaced and integrated within the housing without requiring additional axial space for adjustment mechanisms.
3Ease of operation
If the spiders are radially spaced apart from the transmission central axis, then the friction rollers can engage the friction discs, but axial and radial forces are generated that complicate the assembly
Solution Approach 1:
The patent uses the counterbalancing effect of the mirror-symmetric arrangement of the two spiders. The first spider on the left side and the second spider on the right side generate equal and opposite forces that cancel each other out. This counterbalancing eliminates the need for additional force-balancing mechanisms and simplifies the overall assembly.
Solution Approach 2:
While the overall arrangement is symmetric, the patent introduces asymmetric elements in the form of the threaded connection on the spider sleeve. The thread pairing converts rotational movement into radial spacing changes, creating an asymmetric force distribution that is controlled and manageable, allowing the friction rollers to engage the friction discs effectively while maintaining force balance.
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 design reduces space requirements and complexity, enabling easier installation and reducing costs by canceling out axial and radial forces, allowing for a more straightforward and force-free assembly of the drive unit.
Implementation Method 1
the thread pairing coupling the spiders being adapted in such a way that a relative rotation of the spiders effects a change in the spacing thereof
Implementation Method 2
a set of friction rollers are non-positively contacted between the friction discs and are each rotationally supported about a roller axle
Implementation Method 3
allowing for adjustment of the transmission ratio through torsional twisting of the spiders
Data Source
AI summary
Traction transmission having a first and a second component transmission (26a, b) which are of mirror-symmetrical construction with respect to one another and are arranged axially adjacently in a housing (12), in each case comprising—an axially inner drive friction disc (28a, b) and an axially outer complementary friction disc (32a, b) which are arranged coaxially and can be rotated relative to one another about a transmission central axis, and—a set of friction rollers (40) which make non-positive contact between the friction discs (28a, b, 32a, b) and are mounted such that they can be rotated about in each case one roller axle (44), wherein the roller axles (44) are pivotably mounted in a manner which is spaced apart radially from the transmission central axis on a star-shaped spider (38a, b) which can be moved ax Lilly in relation to the transmission central axis, wherein the spiders (38a, b) are arranged on a common spider sleeve (50) and are coupled to one another at a variable spacing via an axially extending thread pairing (52), wherein—the complementary friction discs (32a, b) are arranged fixedly on a common output shaft (34) which is mounted in the housing such that it is fixed axially and can be rotated, —the spacing of the drive friction discs (28a, b) from one another can be varied by means of a spacing setting device (60), and—the spider sleeve (50) is mounted such that it can be displaced axially relative to the housing (12), wherein the first spider (38a) which is assigned to the first component transmission (26a) is connected fixedly to the housing (12) so as to rotate with it, the second spider (38b) which is assigned to the second component transmission (26b) can be rotated relative to the housing (12) by means of an angular position setting device (54b, 58), and the thread pairing (52) which couples the spiders (38a, b) is set up in such a way that a relative rotation of the spiders (38a, b) brings about a change in the spacing thereof.