Hooking Lever Cam Assembly for Axial Backlash Recovery

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Solution Overview

Problem

Existing assemblies of rotating units and supports face issues with axial backlash due to the absence of a counterforce, leading to unreliable engagement and the need for large tolerances.

Innovation Solution

A hooking lever with a cam profile is used to recover axial backlash by engaging a surface during rotation, ensuring precise axial positioning through a hooking lever mechanism with a first and second lever part, allowing snap connections and force transmission.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If no counterforce is applied to prevent axial movement of the rotating element, then the assembly structure is simpler, but axial backlash cannot be recovered and engagement reliability deteriorates

Engineering Contradiction:
Improveassembly structureVSAvoidengagement reliability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The cam profile is pre-formed on the hooking lever to automatically apply axial counterforce during the assembly process. As the hooking lever rotates into place, the cam profile automatically pushes the rotating element axially to eliminate backlash before final engagement, ensuring reliable connection without requiring external counterforce mechanisms.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The hooking lever performs dual functions: it both connects the rotating element to the support and simultaneously applies the necessary axial counterforce through its cam profile. The structure serves itself by integrating the backlash recovery mechanism into the assembly operation, eliminating the need for separate counterforce application devices.

Inventive Principle:
Principle #25Self-service

2Ease of manufacture

If large axial backlash is accepted to achieve engagement, then the assembly process is easier, but the axial positioning precision deteriorates

Engineering Contradiction:
Improveassembly processVSAvoidaxial positioning precision
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The hooking lever transitions from a static connection element to a dynamic mechanism that actively adjusts axial positioning during assembly. The rotatable second lever part with cam profile dynamically applies varying axial forces throughout the assembly process, automatically compensating for dimensional variations and achieving precise positioning without requiring tight manufacturing tolerances.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The cam profile changes the axial position parameter of the rotating element during the assembly process. As the hooking lever rotates, the cam profile progressively adjusts the axial distance between the rotating element and support, transforming the positioning from a fixed initial state to a controlled final state with precise axial alignment.

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If a hooking lever with cam profile is used to recover axial backlash, then axial positioning precision is improved, but the device complexity increases

Engineering Contradiction:
Improveaxial positioning precisionVSAvoidhooking lever mechanism
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The hooking lever merges multiple functions into a single integrated component: mechanical connection, axial backlash recovery through cam profile, and force transmission to the control device. By combining these functions in one element rather than using separate components, the design achieves precise axial positioning while minimizing overall device complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The hooking lever is designed as a multi-functional element that performs connection, backlash recovery, and force transmission simultaneously. The cam profile on the second lever part enables the same component to serve both as a mechanical connector and as a positioning mechanism, reducing the need for additional specialized parts.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 achieves precise axial positioning with narrow tolerances, enabling reliable engagement and coupling of the rotating unit to a control device.

Implementation Method 1

the second lever part is provided with a cam profile configured to engage a surface of the support during rotation from the initial mounting position to the final mounting position, so as to raise the hooking lever and the shaft with respect to said surface of the support, recovering any axial backlash between the rotating element and the support

Methodology Applied
Scientific EffectCam mechanism: Cam

Data Source

PatentEP4553325B1Assembly comprising a rotating unit and a support, with a hooking lever for axial backlash recovery
Publication Date: 2026.03.25 DENSO THERMAL SYST SPA
  • EP4553325B1 patent drawingFigure 1
  • EP4553325B1 patent drawingFigure 2
  • EP4553325B1 patent drawingFigure 3~4

AI summary

Assembly comprising a rotating unit (13, 20) and a support (11), wherein the rotating unit comprises a rotating element (13) and a hooking lever (20). The hooking lever (20) comprises a first lever part (21) mounted on an end (14a) of a shaft (14) of the rotating element (13) and is provided with a first clip (21d) configured to snap on a first hooking seat (14e) formed on an end (14a) of the shaft (14), and a second lever part (23) hinged to the first lever part (21). The second lever part (23) is provided with a second clip (23e) configured to snap on a second hooking seat (21g) formed on the first lever part (21). The second lever part (23) is provided with a cam profile (23g) configured to lift the hooking lever (20) and the shaft (14) relative to the support (11), recovering axial backlash between the rotating element (13) and the support (11). The second lever part (23) is provided with a force transmission portion (23a") configured to be coupled with a device for controlling the rotating element (13).