Drive Pinion Tilting Compensation in Machine Tool Racks
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Solution Overview
Problem
In punch-laser combination machines, the drive pinion tends to tilt during compensation movements due to production and thermal expansion tolerances, leading to irregular engagement of tooth arrangements and increased wear, which impairs force transmission between the rack and pinion.
Innovation Solution
A drive device with a resilient toothed element supported by a bearing device and a torque compensator, featuring a redirection member that counteracts tilting by applying a redirection force, preventing undesirable tilting movements through a reaction rotation movement, thus maintaining the desired orientation of the tooth arrangements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the drive pinion is pre-tensioned and allowed compensation movements, then production and assembly tolerances are accommodated, but the drive pinion tilts during compensation movements causing irregular tooth engagement
Solution Approach 1:
The compensation mechanism is segmented into independent components: the resilient support allows linear compensation movements while the redirection member with pivot axes handles rotational compensation separately. This separation enables each component to specialize in one type of movement, preventing tilting while maintaining adaptability.
Solution Approach 2:
The redirection member acts as an intermediary between the resilient support and the drive pinion. It receives redirection forces from the resilient support and transforms them into reaction rotation movements that counteract tilting, mediating between compensation needs and engagement stability.
2Reliability
If linear guides are used to forcibly guide the drive pinion, then tilting movements are prevented, but the device complexity increases
Solution Approach 1:
The complex linear guide system is replaced with a more elegant mechanical substitution: the redirection member with its pivot axes naturally generates the necessary reaction rotations through its geometry and articulation points, achieving tilting prevention without rigid linear guides.
Solution Approach 2:
The system changes from fixed rigid guidance to dynamic parameter-based compensation. The redirection member's pivot axes are positioned at specific distances from the drive pinion axis, creating a geometric relationship that automatically adjusts the reaction rotation angle based on the redirection force magnitude, adapting to different operating conditions.
3Adaptability or versatility
If the drive pinion is resiliently supported to allow compensation movements, then adaptability improves, but tilting movements occur due to redirection forces
Solution Approach 1:
The redirection member provides a counterbalancing mechanism that generates reaction rotation movements opposing the tilting effect of redirection forces. The pivot axes are positioned to create a counter-torque that balances the destabilizing moment, maintaining orientation stability while allowing compensation.
Solution Approach 2:
The solution addresses the tilting problem by introducing a rotational dimension (reaction rotation about the drive pinion axis) to counteract the linear displacement dimension (redirection force parallel to engagement axis). This dimensional transformation converts a linear stability problem into a rotational balance problem.
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 effectively stabilizes the tooth arrangements, preventing tilting and maintaining a tilt-free orientation, thereby reducing wear and ensuring reliable engagement between the rack and pinion, while being structurally simple, maintenance-free, and space-efficient.
Implementation Method 1
The resilient toothed element, under a redirection action of a redirection force (FD) applied by the other of the first and second toothed elements to the resilient toothed element parallel to the engagement axis, and counter to a restoring action of a restoring force
Implementation Method 2
For the resilient toothed element, there is provided a torque compensator which counteracts a redirection rotation movement of the resilient toothed element that results from the redirection force (FD) about a rotation axis that extends parallel to the movement axis of the resilient toothed element
Data Source
AI summary
A drive device for a movement unit of a machine tool includes a first toothed element driven by a drive motor and provided as a drive pinion including a first tooth arrangement and a second toothed element provided as a toothed rack including a second tooth arrangement. One of the first and second toothed elements is connected to a machine frame, and the other of the first and second toothed elements is connected to the movement unit. The first and second toothed elements are moved relative to each other along a movement axis of the first and second toothed elements by the drive motor via a meshing between the first and second tooth arrangements and via an engagement between the first and second tooth arrangements along an engagement axis that extends perpendicularly to the movement axis.