Shift Drum Assembly With On-Demand Stop for Endless Rotation
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Solution Overview
Problem
Existing shift drum arrangements in motor vehicle transmissions have limited rotation angles due to fixed stops, making it impossible to rotate the shift drum beyond 360°, which is a constraint for transmissions requiring wider rotation ranges, especially in hybrid systems where endless rotation in both directions is advantageous.
Innovation Solution
A shift drum arrangement with endlessly rotatable shift drum grooves and a reference element that allows the shift drum to rotate freely in both directions, utilizing a stop device with a pivotally mounted stop element and an actuator to block rotation at a specific reference angle, enabling endless rotation and precise referencing of the switching angle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a stop element is permanently connected to the shift drum body to reference rotational position, then the rotational position can be referenced, but the maximum rotation angle is limited to less than 360°
Solution Approach 1:
The stop element is made dynamically movable relative to the shift drum body through pivotal mounting. This allows the stop element to be positioned only when needed for referencing the rotational position (0°), while permitting the shift drum to rotate freely through more than 360° during normal operation. The dynamic positioning resolves the contradiction by separating the referencing function from continuous rotation constraints.
Solution Approach 2:
The stop device is segmented into a stop element that can be independently positioned relative to the shift drum body. This segmentation allows the referencing function to be performed at specific moments without constraining the overall rotation range of the shift drum, enabling both precise positioning and extensive rotation capability.
2Measurement precision
If wide and massive stops are used to reference rotational position, then the referencing function is improved, but the available rotation angle of the shift drum is significantly reduced
Solution Approach 1:
The stop element is designed as a lightweight, pivotally mounted component rather than a wide and massive fixed stop. This dynamic design allows the stop element to be positioned only when needed for referencing, minimizing its interference with the shift drum's rotation range while maintaining effective positional referencing capability.
3Device complexity
If the stop element is fixed to the shift drum body, then the structure is simple, but the shift drum cannot rotate more than 360°
Solution Approach 1:
The stop element is pivotally mounted rather than fixed, adding minimal complexity to the structure. This pivotal connection allows the stop element to remain attached to the shift drum body while enabling relative movement, thus permitting rotation beyond 360° without requiring complete removal or complex detachment mechanisms.
Solution Approach 2:
The pivotal mounting acts as an intermediary between the stop element and the shift drum body, allowing both components to remain connected while enabling relative motion. This intermediary connection resolves the contradiction by providing a simple yet effective mechanism that allows extensive rotation while maintaining the ability to reference rotational position.
Data Source
Figure 1a~1b
Figure 2
Figure 3
AI summary
The invention relates to a gear shift drum assembly (32) for a shift device (30) of a transmission assembly (16), in particular for motor vehicles, comprising a gear shift drum body (34) and a first shift element (55), wherein the gear shift drum body (34) can be rotated about an axis of rotation (36) and has a shift contour running around the circumference of the outer surface, wherein the shift contour is formed in an axial and/or radial direction, in which the shift element engages, which can be shifted in the axial direction of the gear shift drum body by means of the shift contour when rotating the gear shift drum body (34), and comprising a stop mechanism (60) for referencing a rotational position of the gear shift drum body (34). The gear shift drum assembly (32) is to comprise a gear shift drum body (34) which can be continuously rotated in both rotational directions, wherein a simple option for referencing the shift angle / rotational angle is also made possible. This is achieved in that the shift contour comprises at least one shift section / shift angle range, which is assigned to a reference angle position, and in that the stop mechanism (60) comprises a shift stop which can be activated into an activation position as required and/or in a predefined shift angle / shift angle range, in such a way that the rotation of the gear shift drum body (34) is blocked in the reference angle position.