Functional Tolerancing

Description of Mechanical Interfaces and Mechanical Junctions of the Damper Mechanism

This topic describes Mechanical Interfaces (MI) and Mechanical Junctions (MJ) of the damper mechanism.

This page discusses:

 

See Also
Working with Mechanical Interfaces

Mechanical Interface (MI)

A Mechanical Interface (MI) is a structured set of surfaces of a part that are designed to mate to the other part.

Surfaces Description
Primary surfaces

Constraints the most the position of the part when mated to the other part
Secondary surfaces

 Constraints the most, after the primary ones, the position of the part when mated to the other part
Tertiary surfaces

 Constraints the less the position of the part when mated to the other part
Maintain surfaces

Maintains the part in the position set by the primary, secondary, and tertiary surfaces when mated to the other part

The intermediary parts (pins, screws, bearings, etc.) can be managed by defining appropriate clearances.

You can create the MI features in a 3D Shape using one the following commands:

  • Mechanical Interface Creation: Creation of a MI feature into the edited 3D Shape.
  • Mechanical Interface Instantiation:

    Creation of MI feature from a MI template PLM object into the edited 3D Shape.

    MI templates can be created and managed using the Mechanical Interface Templates Captureapp.

  • Mechanical Interfaces Reveal : Automatic creation of MI features from copied geometric features (copy as result, copy as specification, power copy, user feature, etc.).

You can refine the MI features using the Mechanical Interfaces Assistant command. The command verifies the assembly consumption of the interfaces:

  • Connected by engineering connections
  • Positioned (in front of an opposite MI)
  • Not connected or positioned: Connections to other systems or design problems

It also verifies the quality and the completeness of the interface definition as below:

  • Identify the useful portion or extension of the functional surfaces:
    • Actions: Create, update, edit, or delete the restricted area
    • Actions: Create, update, edit, or delete the extended cylinder
  • Identify the geometric inconsistencies

Damper Mechanism Example: Mechanical Interfaces of the Lower Support Part

MI Connected to Upper Support

It connects the lower support part to the upper support part through the following features:

  • A plane primary contact surface
  • A cylinder secondary surface using an intermediary pin mounted with tightening in the hole
  • A cylinder tertiary surface using an intermediary pin mounted with tightening in the hole
  • A thread maintain surface using an intermediary screw



MI Connected to Damper

It connects the lower support part to the damper part through:

  • A cylinder primary surface with clearance
  • A plane secondary contact surface



MI connected to plate (external environment)

It connects the lower support part to the external environment through:

  • A plane primary contact surface
  • A cylinder secondary surface with clearance

Damper Mechanism Example: Mechanical Interfaces of the Upper Support Part

MI Connected to Lower Support

It connects the upper support part to the lower support part through:

  • A plane primary contact surface
  • A cylinder secondary surface with clearance
  • A cylinder tertiary surface with clearance
  • A cylinder maintained with clearance


MI Connected to Damper

It connects the upper support part to the damper part through:

  • A cylinder primary surface with clearance
  • A plane secondary contact surface

Damper Mechanism Example: Mechanical Interfaces of the Damper Part

MI Connected to Upper Support

It connects the damper part to the upper support part through:

  • A cylinder primary surface with clearance
  • A plane secondary contact surface

MI Connected to Lower Support

It connects the damper part to the lower support part through:

  • A cylinder primary surface with clearance
  • A plane secondary contact surface

Mechanical Junction (MJ)

A Mechanical Junction (MJ) is an unstructured set of MI features of a part used for setting and maintaining in position a component in an assembly. You can create MJ features using the Mechanical Junction Creation command.

There are three types of MJ:

  • Main part: This junction fully defines the positioning of the considered part.
  • Main block: This junction fully or partially defines the positioning of a set of parts (block) which includes the considered one.
  • Auxiliary: This junction fully or partially defines the positioning of another part or block.
A main block or an auxiliary MJ is fractioned when it partially defines the positioning in the assembly.

Damper Mechanism Example: MJ of the Lower Support Part

MJ Positioned on Plate (External Environment)

It is a nonfractioned main block MJ as it fully defines the positioning of the complete assembly (including the lower support part in the external environment).



MJ Positioning Upper Support

It is a nonfractioned auxiliary MJ as it fully defines the positioning of the upper support part in the assembly.





MJ Partially Positioning Damper

It is a fractioned auxiliary MJ as it partially defines the positioning of the damper part in the assembly.



Both primary and secondary positioning surfaces are fractioned. In both cases, the two portions are connected through the positioning upper support MJ of the lower support part.



Damper Mechanism Example: Mechanical Junctions of the Upper Support Part

MJ Positioned on Lower Support

It is a main part MJ as it defines the positioning of the upper support part in the assembly.

The (M) button lets you specify that the local clearance of the maintaining cylindrical surface is favorable or not for the mounting of the upper support part in the assembly.

: The clearance is favorable.

: The clearance is unfavorable.

By default, the button selected.

MJ Partially Positioning Damper

It is a fractioned auxiliary MJ as it partially defines the positioning of the damper part in the assembly.



Both primary and secondary positioning surfaces are fractioned.

In both the cases, the two portions are connected through the positioned on lower support MJ of the upper support part.



Damper Mechanism Example: MJ of the Damper Part

MJ Positioned on Lower Support and Upper Support Block

It is a main part MJ as it defines the positioning of the damper part itself in the assembly.



When the MJ is made of several MI components, it is required in some cases to redefine the feature type and clearance descriptions: