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CN-115464167-B - Machine tool spindle impact protection system

CN115464167BCN 115464167 BCN115464167 BCN 115464167BCN-115464167-B

Abstract

The invention discloses a machine tool spindle impact protection system which comprises a vibration sensor, a low-pass filter, a self-learning data judging module and an industrial controller, wherein the vibration sensor is arranged at a position close to a spindle and is connected with the low-pass filter, the low-pass filter is connected with the self-learning data judging module, and the industrial controller is connected with the self-learning data judging module. The invention belongs to the technical field of manufacturing and numerical control processing systems, and particularly provides a machine tool spindle impact protection system which uses a vibration sensor and is provided with a differentiator and a comparator, obtains a DAC output level for comparing with the output of the differentiator and transmitting signals to a PLC or a contactor for power failure through learning vibration data in normal operation, and the differentiator can pre-judge abrupt change of the signals in advance, so that the impacted spindle is protected in microsecond time, damage to the spindle is further reduced, and cost is conveniently reduced.

Inventors

  • WANG CHUANGUO

Assignees

  • 上海杨铁精密机械有限公司

Dates

Publication Date
20260505
Application Date
20220906

Claims (7)

  1. 1. The machine tool spindle impact protection system is characterized by comprising a vibration sensor, a low-pass filter, a self-learning data judging module and an industrial controller, wherein the vibration sensor is arranged at a position close to a spindle, the output end of the vibration sensor is connected with the input end of the low-pass filter, the output end of the low-pass filter is connected with the input end of the self-learning data judging module, and the industrial controller is connected with the output end of the self-learning data judging module; The self-learning data judging module comprises an AD collector, a main controller, a DA converter, a differentiator and a comparator, wherein an output shaft of the vibration sensor is connected with the AD collector through the low-pass filter, an output end of the AD collector is connected with an input end of the main controller, an output end of the main controller is connected with an input end of the DA converter, an output end of the low-pass filter is connected with an input end of the differentiator, an output end of the differentiator and an output end of the DA converter are both connected with the comparator, and the industrial controller is connected with an output end of the comparator; the output signal of the differentiator is divided into two paths, wherein one path of output signal enters the positive input end of the comparator, and the other path of output signal enters the AD collector.
  2. 2. The machine tool spindle impact protection system according to claim 1, wherein the main controller is internally provided with a storage unit, and the main controller reads data of the AD collector for learning related data when the spindle is in normal operation and stores the related data in the storage unit.
  3. 3. A machine tool spindle impact protection system according to claim 2, wherein the main controller outputs a minimum upper limit level to the negative input of the comparator via the DA converter.
  4. 4. The machine tool spindle impact protection system of claim 1, wherein the industrial controller is a PLC or a contactor.
  5. 5. The machine tool spindle impact protection system according to claim 1, wherein the output end of the comparator is connected with a trigger, and an input signal of the trigger can directly drive the contactor to disconnect the power supply or input the signal to the PLC controller to perform power-off operation by the PLC.
  6. 6. The machine tool spindle impact protection system according to claim 1, wherein the vibration sensor output signal is an analog signal, and the analog signal is filtered by a low-pass filter to remove other high-frequency components and retain needed frequency components.
  7. 7. The machine tool spindle impact protection system according to claim 1, wherein the cutoff frequency of the low pass filter is set to be 30 times or more of the spindle vibration frequency.

Description

Machine tool spindle impact protection system Technical Field The invention belongs to the technical field of manufacturing and numerical control machining systems, and particularly relates to a machine tool spindle impact protection system. Background The spindle is the most core part of the machine tool, and when the spindle is worn or impacted by a blade, the machining precision is seriously affected, and in particular, the precision of the electric spindle is reduced by more than ten times. Therefore, the damage to the main shaft is reduced to the greatest extent by cutting off the power supply in a safe time range when the main shaft is impacted, and the machining precision is ensured. In the prior art, a main controller collects data of a triaxial acceleration sensor arranged on a main shaft, a frequency spectrum of the main shaft in normal operation is obtained, and a peak value is calculated and stored. When the data is more than the upper limit value, the main controller sends an IO value signal to the machine tool PLC, and the PLC cuts off the total power supply. In the above technique, the signal needs to be low-pass filtered, and then the acquired data is processed, such as fast fourier transform or wavelet transform. The cut-off frequency of the low-pass filter will generally select the working frequency of the spindle, and the amplitude of the signal will be attenuated by-3 db after passing through the low-pass filter due to the amplitude-frequency characteristic of the low-pass filter, and the cut-off frequency will generate larger delay. The choice of the low-pass filter cut-off frequency will affect the rise time of the signal, which is a pair of contradictors, and it is not possible to obtain a clean signal and obtain a fast response time. And the processing of the data also requires time, if the performance of the processor is low, the power-off protection signal cannot be sent timely, so that the main shaft cannot be protected timely, and if the performance of the processor is high, the price of the processor can lead to the increase of the overall cost, and the triaxial acceleration sensor with high sensitivity is high in price and is not beneficial to mass production. Disclosure of Invention Aiming at the situation, in order to overcome the defects of the prior art, the invention provides a protection system with a differentiator and a comparator by using a common mechanical vibration sensor, and the protection system for the machine tool spindle impact is convenient to reduce cost by learning vibration data in normal operation and obtaining a DAC output level for directly transmitting signals to a PLC or a contactor to power off when the DAC output is exceeded compared with the DAC output, and the differentiator can pre-judge abrupt change of the signals in advance, thereby realizing protection of the impacted spindle in microsecond time, further reducing damage of the spindle. The technical scheme includes that the machine tool spindle impact protection system comprises a vibration sensor, a low-pass filter, a self-learning data judging module and an industrial controller, wherein the vibration sensor is arranged at a position close to a spindle, the output end of the vibration sensor is connected with the input end of the low-pass filter, the output end of the low-pass filter is connected with the input end of the self-learning data judging module, and the industrial controller is connected with the output end of the self-learning data judging module. As the scheme of further elaboration, self-learning data judge module includes AD collector, main control unit, DA converter, differentiator and comparator, vibration sensor's output shaft passes through low pass filter with AD collector is connected, AD collector's output is connected with main control unit's input, main control unit's output is connected with DA converter's input, low pass filter's output is connected with the input of differentiator, the output of differentiator and DA converter's output all are connected with the comparator, industrial controller is connected with the output of comparator. Preferably, the output signal of the differentiator is divided into two paths, wherein one path of output signal enters the positive input end of the comparator, and the other path of output signal enters the AD collector. Further, a storage unit is arranged in the main controller, and the main controller reads data of the AD collector and is used for learning related data when the spindle normally operates and storing the related data into the storage unit. In a preferred embodiment, the main controller outputs the minimum upper limit level to the negative input terminal of the comparator through the DA converter. In a preferred scheme, the industrial controller is a PLC or a contactor. As a further elaboration scheme, the output end of the comparator is connected with a trigger, and an input signal of the trigger can directly d