Engagement Device Tooth Surface Alignment Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional engagement devices may experience insufficient meshing due to small contact areas between inclined surfaces of drive and driven gears, leading to increased impact and reduced durability.
Innovation Solution
An engagement device with a first member having engaged teeth and a second member with engaging teeth, where the teeth are arranged to face and approach each other at specific angles, and a control unit manages the relative rotation and movement to ensure proper engagement and torque change, enhancing the contact area and durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the inclined surfaces of the drive gear and driven gear are used for engagement, then the engagement operation can be initiated, but the contact area between meshing surfaces becomes small leading to insufficient meshing
Solution Approach 1:
The patent applies preliminary action by rotating the drive gear in the negative rotation direction before axial engagement to pre-position the tooth surfaces. This preliminary rotational action ensures that the large tooth surfaces (11b, 12b) are properly aligned and will make full contact during subsequent axial movement, rather than allowing the smaller inclined surfaces to engage first.
Solution Approach 2:
The patent employs dynamics by changing the rotation direction of the drive gear during the engagement process. The rotation direction is switched from negative to positive after a predetermined axial movement, allowing dynamic adjustment of tooth surface contact. This dynamic control ensures optimal contact area between meshing surfaces throughout the engagement sequence.
2Productivity
If the contact area between meshing surfaces is small, then the engagement operation can proceed, but contact pressure is increased leading to increased impact and reduced durability
Solution Approach 1:
The drive gear is rotated in the negative rotation direction before axial engagement to pre-position the tooth surfaces. This preliminary action ensures that when axial engagement occurs, the large tooth surfaces are already aligned, distributing the contact pressure over a larger area and reducing peak stresses during the engagement process.
Solution Approach 2:
The patent changes the rotation direction parameter of the drive gear from negative to positive after predetermined axial movement. This parameter change optimizes the contact conditions between tooth surfaces, ensuring that the engagement occurs under controlled pressure conditions that reduce impact and improve durability.
3Area of stationary object
If the rotation direction of the first member is changed from negative to positive during engagement, then the meshing area is increased, but the control complexity increases
Solution Approach 1:
The engagement process uses periodic action by executing a sequence of discrete steps: first rotating in the negative direction, then moving axially, and finally switching to positive rotation. This periodic control sequence simplifies the management of complex multi-directional operations by breaking them into manageable, repeatable phases with clear transition criteria.
Solution Approach 2:
The control unit uses feedback by monitoring the axial movement distance to determine when to switch the rotation direction from negative to positive. This feedback-based control ensures that the rotation direction change occurs at the optimal moment to maximize meshing area while maintaining simple control logic based on measurable physical parameters.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
When a piece 7 and a sleeve 8 are engaged with each other, an engagement device 1 controls an actuator 9 to move the sleeve 8 in a direction approaching the piece 7 with the piece 7 rotating in a negative rotation direction (a direction in which small tooth surfaces 11a of dog teeth 11 of the piece 7 and small tooth surfaces 12a of dog teeth 12 of the sleeve 8 face and approach each other) relative to the sleeve 8, and further controls a first motor generator MG1 to change the rotation speed of the piece 7 from a negative rotation speed to zero or more after a predetermined stroke condition for the movement of the sleeve 8 relative to the piece 7 is satisfied. Accordingly, it is possible to reliably perform the engagement and improve the durability.