Eccentric Cam Drive Device Power Optimization

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Solution Overview

Problem

Cam drive devices with constant curvature profiles tend to increase power consumption when attempting to stop rotation with a non-concentric curved portion in contact with a displacement body, due to shape errors among individual cams.

Innovation Solution

The implementation of an eccentric cam drive device with a controller that adjusts the excitation current to the stepping motor based on the rotation stop position, using both concentric and non-concentric curved portions to manage contact with the displacement body, thereby optimizing power usage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the cam is stopped with a non-concentric curved portion in contact with the displacement body, then the displacement body can be displaced by an intended displacement amount, but the power consumption of the motor increases

Engineering Contradiction:
Improvedisplacement amountVSAvoidpower consumption
Core Design Contradiction:
Manufacturing precisionVSUse of energy by moving object

Solution Approach 1:

The patent changes the physical state of the motor by controlling excitation current parameters. The controller adjusts the excitation current to generate appropriate stall torque at different cam rotation stop positions, enabling precise displacement control while managing power consumption through parameter optimization

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The system implements feedback control by detecting the cam rotation stop position and adjusting the excitation current accordingly. The controller receives position information and modifies the motor's excitation state to maintain desired displacement while optimizing energy consumption based on actual operating conditions

Inventive Principle:
Principle #23Feedback

2Stability of the object's composition

If the excitation current is increased to prevent cam rotation at non-concentric position, then the cam remains stationary, but the power consumption increases

Engineering Contradiction:
Improvecam position stabilityVSAvoidpower consumption
Core Design Contradiction:
Stability of the object's compositionVSUse of energy by moving object

Solution Approach 1:

The patent applies dynamic control by adjusting the excitation current based on the cam's rotation stop position. Rather than maintaining constant high current, the system dynamically modifies the excitation level to provide just enough stall torque to maintain position stability, optimizing the balance between stability and energy consumption

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The controller changes the excitation current parameter according to the detected cam position. By adjusting this electrical parameter, the system achieves position stability with minimal energy consumption, avoiding the need for continuously high current while maintaining cam stationary state when required

Inventive Principle:
Principle #35Parameter changes

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 configuration effectively suppresses power consumption increases by varying the excitation current according to the rotation stop position, preventing unnecessary rotation and maintaining efficient motor operation.

Implementation Method 1

a stepping motor, and a power source to output electric current to be supplied to the stepping motor

Methodology Applied
Scientific EffectElectromagnetic interaction: Electromagnetic Induction

Data Source

PatentEP3333635B1Cam drive device and image forming apparatus incorporating same
Publication Date: 2020.07.01 RICOH CO LTD
  • EP3333635B1 patent drawingFigure 1
  • EP3333635B1 patent drawingFigure 2
  • EP3333635B1 patent drawingFigure 3A~3B

AI summary

A cam drive device (60) includes a cam (61) to rotate; a displacement body (62) to be displaced in response to a change in a rotation position of the cam (61) in contact with the displacement body (62); a motor (63) to rotate the cam (61); and a power source (202) to output an electric current to be supplied to the motor (63). An electric current to cause a stall torque to the motor (63) being a stop state is changed in response to a change in a rotation stop position of the cam (61).