Machine Tool Tilt Device Backlash Prevention via Cylinder Pressure Control
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Solution Overview
Problem
Tilt devices for machine tools face challenges with backlash due to inversion of drive torque when the inclination angle exceeds a predetermined limit, leading to increased motor size requirements to handle unbalance moments, especially with heavy workpieces.
Innovation Solution
A tilt device with a support member, drive motor, auxiliary cylinder, and control device that maintains a consistent drive torque direction by ensuring the assistive moment from the auxiliary cylinder is always less than the gravitational moment, preventing backlash and reducing motor size through controlled cylinder pressure adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a large drive motor is used to support the unbalance moment generated in the tilt member, then the tilt member can be maintained in the inclined state, but the device size increases
Solution Approach 1:
A cylinder device is introduced as an intermediary component to assist the drive motor. The cylinder device generates an urging force that acts on the tilt member to counteract the unbalance moment, thereby reducing the load on the drive motor and allowing for a smaller motor size while maintaining the ability to hold inclined positions.
Solution Approach 2:
The cylinder device provides an opposing force (urging force) that counteracts the gravitational unbalance moment acting on the tilt member. This counterbalancing approach reduces the net moment that the drive motor must overcome, enabling motor size reduction.
2Power
If the cylinder device is coupled to the tilt member to cancel out the unbalance moment, then the load on the drive motor is reduced, but the drive torque direction inverts when the inclination angle exceeds a predetermined angle, causing backlash
Solution Approach 1:
The system dynamically adjusts the urging force from the cylinder device based on the inclination angle of the tilt member. The control device monitors the inclination angle and modulates the cylinder output to ensure the urging force always acts in the same rotational direction, preventing torque inversion and backlash while maintaining reduced motor load.
Solution Approach 2:
The control device implements feedback control by monitoring the inclination angle of the tilt member and adjusting the cylinder urging force accordingly. This feedback mechanism ensures that the assistive moment from the cylinder never exceeds the unbalance moment, preventing the drive torque direction from inverting and eliminating backlash conditions.
3Power
If the assistive moment from the auxiliary cylinder exceeds the gravitational moment, then the drive torque direction inverts, but this causes backlash in the tilt member
Solution Approach 1:
The control device continuously monitors the inclination angle and calculates the gravitational moment, then adjusts the auxiliary cylinder pressure to ensure the assistive moment remains less than the gravitational moment. This feedback control prevents the assistive moment from exceeding the gravitational moment, thereby preventing drive torque inversion and backlash.
Solution Approach 2:
The system changes the pressure parameter of the auxiliary cylinder dynamically based on the inclination angle. By adjusting the cylinder pressure to maintain the condition where assistive moment < gravitational moment, the system prevents torque direction inversion and backlash while still providing load reduction benefits.
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 prevents backlash and reduces the size of the drive motor by maintaining a consistent drive torque direction and alleviating the load on the motor, even with heavy workpieces, by ensuring the assistive moment is always less than the gravitational moment across the tilt member's range.
Implementation Method 1
a moment about the swing axis generated in the tilt member by a gravitational force
Implementation Method 2
an auxiliary cylinder that is coupled to the tilt member and that provides a cylinder pressure to assist swing of the tilt member
Data Source
AI summary
A tilt device includes: a drive motor that provides a drive force for swinging a tilt member; an auxiliary cylinder coupled to the tilt member to assist swing of the tilt member by the drive motor; and a control device that performs drive control of the drive motor and the auxiliary cylinder. In the movable range of the tilt member, a moment about the swing axis generated in the tilt member by the gravitational force is always directed to only one side in the rotational direction, and an assistive moment about the swing axis provided to the tilt member by a cylinder pressure is always directed to only the other side in the rotational direction. The control device fluctuates the cylinder pressure such that the assistive moment is less than the moment generated in the tilt member by the gravitational force.