Rear-Mounted Direct Drive Spindle for Thermal Elongation Control
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Solution Overview
Problem
Existing electric spindles with built-in motors suffer from poor heat dissipation and significant thermal elongation due to heat generated by the stator and rotor during high-speed operations, affecting bearing performance and spindle balance.
Innovation Solution
A motor rear-mounted direct drive spindle design where the torque motor is externally exposed, utilizing a heat insulation ring and labyrinth structure to minimize thermal impact, combined with a cooling system and dynamic balance mechanism to maintain stable temperature and reduce thermal elongation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the motor is mounted between two sets of supporting bearing components (built-in motor structure), then the structure is compact, but the heat generated by the stator and rotor significantly impacts the bearings and output end, causing poor heat dissipation and large thermal elongation of the spindle
Solution Approach 1:
The motor is extracted from the built-in position between the bearings and relocated to the rear end of the spindle housing. This separation removes the heat source from the critical bearing support area, allowing the motor to be externally mounted while maintaining a relatively compact overall structure through optimized spatial arrangement.
Solution Approach 2:
The motor mounting position is shifted from the axial center (between bearings) to the rear end of the spindle housing, utilizing the longitudinal dimension more effectively. This dimensional repositioning allows better heat dissipation pathways while preserving structural compactness.
2Volume of moving object
If the motor is mounted between two sets of supporting bearing components, then the structure is compact, but the heat generated causes large thermal elongation of the spindle
Solution Approach 1:
The motor is extracted from the built-in position and relocated to the rear end, separating the heat source from the spindle's critical dimensional stability area. This reduces thermal coupling and minimizes thermal elongation of the spindle while maintaining compact overall dimensions.
Solution Approach 2:
A heat insulation ring is introduced as an intermediary component between the motor and the spindle housing. This thermal barrier reduces heat transfer from the motor to the spindle structure, minimizing thermal elongation while allowing the compact rear-mounted configuration.
3Volume of moving object
If the motor is mounted between two sets of supporting bearing components, then the structure is compact, but the heat generated deteriorates the working conditions of the output end bearings
Solution Approach 1:
The motor is extracted from the position between the bearings and relocated to the rear end of the spindle housing. This separation eliminates the direct thermal impact on the bearings, significantly improving their working conditions and reliability while maintaining a compact overall structure through the rear-mounted configuration.
Solution Approach 2:
A heat insulation ring is positioned between the motor and the spindle housing to act as a thermal barrier. This intermediary component protects the bearings from motor-generated heat, improving bearing reliability while allowing the compact rear-mounted motor structure.
4Volume of moving object
If the motor is mounted between two sets of supporting bearing components, then the structure is compact, but the heat generated causes poor heat dissipation of the mandrel
Solution Approach 1:
The motor is extracted from the built-in position and relocated to the rear end of the spindle housing. This repositioning creates better thermal pathways for the mandrel, allowing heat to dissipate more effectively away from the mandrel surface while maintaining the compact overall structure through the rear-mounted motor configuration.
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 design achieves effective heat dissipation and reduced thermal elongation, improving bearing life and spindle balance by maintaining a steady temperature and minimizing noise and vibration, thus enhancing the overall structural integrity and performance.
Implementation Method 1
a cooling water channel for cooling the first bearing is provided on the spindle housing
Implementation Method 2
a heat insulation ring or a labyrinth structure is provided between the torque motor and the spindle housing
Data Source
AI summary
A motor rear-mounted direct drive spindle includes a spindle housing; a mandrel that is rotatably disposed within the spindle housing; a bearing; and a torque motor. The bearing includes a first bearing and a second bearing that provide radial and axial support to the mandrel, the first bearing and the second bearing are disposed inside the spindle housing, one end of the mandrel extends outside the spindle housing, the torque motor and the spindle housing are axially aligned, the torque motor includes a rotor and a stator, the end of the mandrel located outside the spindle housing is inserted into and connected to an end of the rotor, and the rotor is fixedly connected to the mandrel. In a motor rear-mounted direct drive spindle, a motor with the motor rear-mounted spindle is entirely exposed outside, thus distancing the motor from a mandrel.