Drive Torque Distribution in Sheet Printing Machines
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Solution Overview
Problem
Sheet-fed offset printing machines with multiple drive motors experience periodic interference excursions leading to low transmittant torques within the gear train, causing position errors and a rapid drop in print quality due to the inability to change torque direction during the printing process.
Innovation Solution
The drive torque of individual motors is calculated as a function of the total drive torque, using functions with degressive, progressive, or constant histories, and divided based on the states of the printing machine, such as speed and motor current, to compensate for position errors and maintain print quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If multiple drive motors are used to distribute drive torque, then the power requirements of the printing press can be met, but periodic disturbances cause tooth flanks to lift or change during the printing process, resulting in rapid drop in print quality
Solution Approach 1:
The patent applies dynamics by making the torque distribution adjustable and adaptive rather than fixed. The control system dynamically adjusts the torque contribution of each drive motor based on real-time operating conditions (speed, acceleration, module position), ensuring that sufficient torque is always transmitted through the gear train to maintain tooth flank contact while meeting power requirements. This dynamic adjustment prevents the periodic disturbances that cause tooth flank lifting.
Solution Approach 2:
The patent changes the parameter of torque distribution from a static fixed ratio to a variable parameter that adapts to operating conditions. By modifying how torque is distributed among multiple drive motors based on speed, acceleration, and module position, the system maintains adequate torque transmission through the gear train, preventing tooth flank separation while still utilizing multiple motors for power delivery.
2Device complexity
If multiple drive motors are used to drive the printing press, then the torque requirements can be distributed, but the transmitted torque becomes very low or reverses direction, causing gear teeth to lose contact
Solution Approach 1:
The patent implements feedback control by continuously monitoring operating parameters (speed, acceleration, module position) and using this information to adjust the torque distribution among drive motors. This feedback mechanism ensures that the torque transmitted through any section of the gear train remains above a minimum threshold required to maintain tooth flank contact, preventing gear teeth from losing contact even when multiple motors are used.
Solution Approach 2:
The system dynamically adjusts torque distribution based on real-time operating conditions rather than using a fixed distribution. This dynamic adaptation ensures that during phases where torque might otherwise reverse or become too low (such as during acceleration or when certain modules are idle), the control system compensates by adjusting motor contributions to maintain adequate torque transmission and tooth flank contact.
3Manufacturing precision
If a single drive motor is used, then the torque direction remains clearly defined and gear teeth stay in contact, but the power and torque distribution flexibility is limited
Solution Approach 1:
The patent applies universality by making the multi-motor drive system capable of functioning in multiple modes: it can operate with all motors active for high-power applications, with reduced motor participation during low-power phases, or with adjusted torque distribution adapted to specific operating conditions. This multi-functionality provides both the torque distribution flexibility of multiple motors and the contact stability approaching single-motor systems by adaptively coordinating motor contributions.
Data Source
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AI summary
The invention relates to a method for reducing the positional error of individual partial images on a printed sheet in a printing press, in particular a sheet-fed offset printing press, which is equipped with at least two drive motors (M1-M3) for generating a total drive torque and a control system for operating the printing press. According to the invention, the drive torque of the individual drive motors is calculated and adjusted accordingly as a function of the total drive torque specified by the control system. Functions (AC) are used for the calculation, comprising one or more sections, with at least one section exhibiting either a degressive, progressive, proportional, or constant curve. The invention further includes a device for carrying out the method.