CN114074290A

CN114074290A - Numerical control grinding machine main shaft feed system

Info

Publication number: CN114074290A
Application number: CN202010803297.0A
Authority: CN
Inventors: 白向锋
Original assignee: Ningbo Siruide Abrasives Technology Co ltd
Current assignee: Ningbo Siruide Abrasives Technology Co ltd
Priority date: 2020-08-11
Filing date: 2020-08-11
Publication date: 2022-02-22

Abstract

The invention relates to a spindle feeding system of a numerical control grinding machine, which comprises a control module, a servo motor, a grating ruler component, a moving arm, a spindle and a grinding head, wherein the servo motor is arranged on the control module; the grating scale component comprises a scale grating and a grating reading head; the invention has the grating ruler component, the grating ruler component starts the servo motor to rotate through the control module, and the servo motor is shut down at a proper time by the control module, the servo motor only serves as an actuating mechanism, and the position of the grinding head is based on actual data measured by the grating reading head, so that the influence of inherent reverse clearance in a transmission mechanism on the feeding precision is thoroughly eliminated, and the grinding precision is greatly improved.

Description

Numerical control grinding machine main shaft feed system

Technical Field

The invention relates to a spindle feeding system of a numerical control grinding machine.

Background

The numerical control machine tool is a product combining an information technology and a mechanical manufacturing technology, represents the technical level and the development trend of modern basic machinery, and is a machine tool for grinding the surface of a workpiece by using a grinding tool.

The existing numerical control grinder spindle feeding system mainly comprises a control module and a servo motor, when an operator inputs a walking instruction in the control module, a PLC control system converts a distance variable into a rotating turn variable and transmits the rotating turn variable to the servo motor, the servo motor stops after rotating corresponding turns, and then a grinding head is moved from a 0 position to an A position, the difference between the actual position and the theoretical position is not large, and the reverse clearance of the spindle is eliminated when the reverse clearance is at the 0 position; however, when an operator inputs a walking instruction in the control module to control the servo motor to move the grinding head from the position a to the position B, the servo motor needs to rotate in the reverse direction, so that the reverse gap in the transmission mechanism is doped into the number of rotation turns, and the difference between the actual position and the theoretical position is large, so that the grinding precision is greatly reduced, and further improvement is needed.

Disclosure of Invention

In view of the current situation of the prior art, the technical problem to be solved by the present invention is to provide a numerically controlled grinder spindle feeding system, in which actual data measured by a grating reading head is used as a basis for operating a servo motor and driving a grinding head to move, so that the influence of the inherent reverse clearance in a transmission mechanism on the feeding precision is completely eliminated, and the grinding precision is greatly improved.

The technical scheme adopted by the invention for solving the technical problems is as follows: the utility model provides a numerically control grinder main shaft feed system, includes control module, servo motor, grating chi subassembly, shifting arm, main shaft and bistrique, and the outside of shifting arm is provided with servo motor, and servo motor links to each other with control module, and the inside of shifting arm is provided with drive mechanism, but the inside main shaft that is provided with vertical lift of lower extreme of shifting arm, and the upper end of main shaft links to each other with drive mechanism, its characterized in that, grating chi subassembly links to each other with control module, drive mechanism links to each other with servo motor's axis of rotation, the lower extreme of main shaft is provided with the bistrique.

Preferably, the grating scale assembly comprises a scale grating and a grating reading head, and the grating reading head is connected with the scale grating; the scale grating is connected with the control module.

Preferably, the grating reading head is arranged on one side of the grinding head.

Compared with the prior art, the invention has the advantages that: the invention has the grating ruler component, the grating ruler component starts the servo motor to rotate through the control module, and the servo motor is shut down at a proper time by the control module, the servo motor only serves as an actuating mechanism, and the position of the grinding head is based on actual data measured by the grating reading head, so that the influence of inherent reverse clearance in a transmission mechanism on the feeding precision is thoroughly eliminated, and the grinding precision is greatly improved.

Drawings

FIG. 1 is a schematic diagram of the structure of the present invention;

fig. 2 is a schematic structural diagram of a spindle feeding system of a numerically controlled grinder in the prior art.

Detailed Description

As shown in fig. 1-2, a numerically controlled grinder spindle feeding system includes a control module, a servo motor, a grating scale assembly, a moving arm, a spindle, and a grinding head; the grating ruler component is connected with the control module, the grating ruler component comprises a scale grating and a grating reading head, a servo motor is arranged on the outer side of the moving arm, the servo motor is connected with the control module, a transmission mechanism is arranged inside the moving arm, the transmission mechanism is connected with a rotating shaft of the servo motor, a main shaft capable of vertically lifting is arranged inside the lower end of the moving arm, the upper end of the main shaft is connected with the transmission mechanism, a grinding head is arranged at the lower end of the main shaft, the grating reading head is arranged on one side of the grinding head, and the direction of the grating reading head is vertically arranged downwards; the grating reading head is connected with the scale grating, and the scale grating is arranged on a fixed part of the numerical control grinding machine; the scale grating is connected with the control module;

the control module adopts a PLC control system, the PLC control system is a programmable logic controller, and is an electronic device specially designed for industrial production and operated by digital operation, and the PLC control system adopts a programmable memory, is used for storing programs in the programmable memory, executing instructions facing users such as logical operation, sequential control, timing, counting, arithmetic operation and the like, and controls various types of machinery or production processes through digital or analog input/output; after the PLC controller is put into operation, its working process is generally divided into three stages, namely, input sampling, user program execution and output refreshing. The completion of the above three phases is referred to as one scanning cycle. During the whole operation period, the CPU of the PLC controller repeatedly executes the three stages at a certain scanning speed.

Inputting a sampling stage:

during the input sampling phase, the PLC controller sequentially reads all input states and data in a scanning manner and stores them into corresponding cells in the I/O map area. And after the input sampling is finished, switching to a user program execution and output refreshing stage. In both phases, the state and data of the corresponding cells in the I/O map region do not change even if the input state and data change. Thus, if the input is a pulse signal, the width of the pulse signal must be greater than one scan period to ensure that the input can be read in under any circumstances.

User program execution stage:

in the user program execution phase, the PLC controller always scans the user program (ladder) sequentially in the top-down order. When each ladder diagram is scanned, the control circuit formed by the contacts on the left side of the ladder diagram is always scanned first, the control circuit formed by the contacts is subjected to logic operation according to the sequence of first left, second right, first up, second down, and then the state of the corresponding bit of the logic coil in the system RAM storage area is refreshed according to the result of the logic operation; or refreshing the state of the corresponding bit of the output coil in the I/O mapping area; or determining whether a special function instruction specified by the ladder diagram is to be executed; that is, during the execution of the user program, only the states and data of the input points in the I/O mapping area will not change, while the states and data of other output points and soft devices in the I/O mapping area or the system RAM storage area may change, and the program execution result of the ladder diagram arranged above will act on the ladder diagram arranged below using these coils or data; in contrast, the ladder diagram arranged below, whose refreshed logic coil states or data can only be effected by the next scanning cycle for the program arranged above.

And (3) an output refreshing stage:

and when the scanning user program is finished, the PLC enters an output refreshing stage. During this period, the CPU refreshes all the output latch circuits according to the corresponding states and data in the I/O mapping area, and then drives the corresponding peripheral devices through the output circuits. At this time, it is the true output of the PLC controller.

The same ladder diagrams are arranged in different orders, and the execution results are different. In addition, the operation result of the scanning user program is different from the parallel operation result of the hard logic of the relay control device. Of course, if the time taken by a scan cycle is negligible for the entire run, there is little difference between the two.

Generally, the scan cycle of the PLC controller includes self-diagnosis, communication, etc., and as shown in the following figure, one scan cycle is equal to the sum of all times of self-diagnosis, communication, input sampling, user program execution, output refresh, etc.

The servo motor is an indirect speed change device of a supplementary motor; the servo motor can control the speed and position accuracy accurately, and can convert the voltage signal into torque and rotating speed to drive a control object. The rotation speed of the rotor of the servo motor is controlled by an input signal and can quickly respond, the servo motor is used as an actuating element in an automatic control system, has the characteristics of small electromechanical time constant, high linearity, starting voltage and the like, and can convert a received electric signal into angular displacement or angular speed on a motor shaft for output. The servo motor is divided into two categories of a direct current servo motor and an alternating current servo motor, and is mainly characterized in that when the signal voltage is zero, the signal voltage has no autorotation phenomenon, and the rotating speed is reduced at a constant speed along with the increase of the torque; the grating ruler is also called as a grating ruler displacement sensor, consists of two parts, namely a ruler grating and a grating reading head, and is a measurement feedback device working by utilizing the optical principle of the grating; grating scales are often applied to closed-loop servo systems of numerically controlled machine tools and can be used for detecting linear displacement or angular displacement. The signal output by the measurement is digital pulse, and the method has the characteristics of large detection range, high detection precision and high response speed; the key part of the grating detection device is a grating reading head which comprises a light source, a convergent lens, an indication grating, a photoelectric element, an adjusting mechanism and the like. The grating reading head has a plurality of structural forms, and is divided into direct receiving type reading heads (or called silicon photocell reading heads, mirror type reading heads, beam splitting mirror type reading heads and metal grating reflection type reading heads) according to the structural characteristics and the using occasions of the reading head.

The working principle is as follows: when an operator inputs a walking instruction in the control module, the designated grinding head rises to A bit, the PLC control system starts a scale grating in the grating scale assembly, and the scale grating starts a grating reading head to measure and calculate the vertical distance between the grinding head and 0 bit in real time; the PLC control system simultaneously starts the servo motor to rotate, then drives the main shaft to move upwards for a corresponding distance by virtue of the transmission mechanism, when the vertical distance between the grinding head and the 0 bit, which is measured by the grating reading head, is equal to the vertical distance between the A bit and the 0 bit, the grating reading head immediately transmits a signal to the scale grating, the scale grating further transmits the signal to the control module, and finally the control module stops the servo motor to rotate, so that the grinding head is finally moved from the 0 bit to the A bit, and the actual position at the moment is slightly different from the theoretical position; similarly, if an operator inputs a walking instruction in the control module, the designated grinding head descends to the B position, the PLC control system starts a scale grating in the grating ruler component, and the scale grating starts a grating reading head to measure and calculate the vertical distance between the grinding head and the B position in real time; the PLC control system simultaneously starts the servo motor to rotate, then drives the main shaft to move upwards for a corresponding distance by means of the transmission mechanism, when the vertical distance between the grinding head and the B position measured by the grating reading head is equal to the vertical distance between the A position and the B position, the grating reading head immediately transmits a signal to the scale grating, the scale grating further transmits the signal to the control module, finally the control module stops the servo motor to rotate, finally the grinding head moves from the A position to the B position, and the actual position and the theoretical position at the moment are slightly different.

The numerical control machine tool is a product combining information technology and mechanical manufacturing technology, and represents the technical level and development trend of modern basic machinery, the numerical control grinding machine tool utilizes a grinding tool to grind the surface of a workpiece, the existing numerical control grinding machine spindle feeding system mainly comprises a control module and a servo motor, when an operator inputs a walking instruction in the control module, a PLC control system converts a distance variable into a rotating turn variable and transmits the rotating turn variable to the servo motor, the servo motor stops after rotating corresponding turns, and then a grinding head is moved from 0 position to A position, the actual position and the theoretical position have little difference, and the reverse clearance of the spindle is eliminated when the spindle is at 0 position; however, when an operator inputs a walking instruction in the control module to control the servo motor to move the grinding head from the A position to the B position, the servo motor needs to rotate in the reverse direction, so that the reverse gap in the transmission mechanism is doped into the number of rotation turns, and the difference between the actual position and the theoretical position is large, so that the grinding precision is greatly reduced; the invention has the grating ruler component, the grating ruler component starts the servo motor to rotate through the control module, and the servo motor is shut down at a proper time by the control module, the servo motor only serves as an actuating mechanism, and the position of the grinding head is based on actual data measured by the grating reading head, so that the influence of inherent reverse clearance in a transmission mechanism on the feeding precision is thoroughly eliminated, and the grinding precision is greatly improved.

Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those skilled in the art that various changes in the embodiments and modifications thereof may be made, and equivalents may be substituted for elements thereof; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. The utility model provides a numerically control grinder main shaft feed system, includes control module, servo motor, grating chi subassembly, shifting arm, main shaft and bistrique, and the outside of shifting arm is provided with servo motor, and servo motor links to each other with control module, and the inside of shifting arm is provided with drive mechanism, but the inside main shaft that is provided with vertical lift of lower extreme of shifting arm, and the upper end of main shaft links to each other with drive mechanism, its characterized in that, grating chi subassembly links to each other with control module, drive mechanism links to each other with servo motor's axis of rotation, the lower extreme of main shaft is provided with the bistrique.

2. The numerically controlled grinding machine spindle feeding system according to claim 1, wherein the grating scale assembly comprises a scale grating and a grating reading head, and the grating reading head is connected with the scale grating; the scale grating is connected with the control module.

3. A numerically controlled grinding machine spindle feed system as claimed in claim 2, in which the raster reading head is provided on one side of the grinding head.