CN102615594B - A method for detecting the grinding force of grinding wheel in the processing of shaft parts - Google Patents

Abstract

The invention belongs to a machining method and particularly relates to a grinding wheel grinding force detection method in a shaft part machining process. The grinding wheel grinding force detection method is characterized in that the method comprises the steps of: firstly detecting and recording motor current signals and position signals in the execution process of a grinding processing program under the condition of no feed, calculating to obtain the distribution rule of electromagnetic pushing force signals and electromagnetic torque signals of a grinding wheel feed shaft driving motor and a workpiece rotating shaft driving motor, obtaining kinematic pair friction and total accelerating and decelerating force of a machine tool in a workpiece rotating direction and a grinding wheel feed direction, taking the kinematic pair friction and the total accelerating and decelerating force as reference signal values, and in the actual grinding process, subtracting the corresponding reference signal values from the measured and calculated electromagnetic pushing force signals and electromagnetic torque signals of the grinding wheel feed shaft driving motor and the workpiece rotating shaft driving motor to obtain the corresponding grinding wheel grinding force signals, wherein the electromagnetic pushing force signals of the grinding wheel feed shaft driving motor mainly correspond to grinding wheel normal grinding force and the electromagnetic torque signals of the workpiece rotating shaft driving motor mainly correspond to grinding wheel tangential grinding force. The grinding wheel grinding force detection method in the shaft part machining process has the advantages of simple principle, reasonable scheme and high accuracy, and is suitable for the grinding force detection and the machining process state monitoring in the grinding process of shaft parts with various specifications.

Description

A method for detecting the grinding force of grinding wheel in the processing of shaft parts

technical field

The invention belongs to the category of mechanical test methods, in particular to a method for detecting the grinding force of a grinding wheel during the processing of shaft parts.

Background technique

In the grinding process of shaft parts, the grinding force of the grinding wheel is an important indicator reflecting the grinding state. The normal range of grinding force reflects the sharpness of the grinding wheel and its ability to remove material from the workpiece being machined. As the grinding process continues, the abrasive grains of the grinding wheel are peeled off and clogged, resulting in a decrease in the sharpness of the grinding wheel, which significantly increases the grinding force of the grinding wheel under the same process conditions. The increase of the grinding force of the grinding wheel will aggravate the deformation of the shaft parts and cause the increase of the surface roughness value, thereby increasing the probability of defective products. Therefore, the detection of the grinding wheel grinding force has important reference significance for ensuring the processing quality of the shaft parts. Usually, the grinding force detection of the grinding wheel in the machining process of shaft parts is divided into normal grinding force detection and tangential grinding force detection. Force sensors, such as piezoelectric dynamometers, not only increase the cost of the machine tool, but also destroy its original structural integrity; for tangential grinding force detection, the existing detection methods are mainly installed on the rotating shaft of the part to rotate However, its high price limits its application in general-purpose processing equipment. In addition, there is also a detection method for estimating the tangential grinding force of the grinding wheel by measuring the instantaneous power of the grinding wheel spindle, but it is limited by the nonlinearity of the friction force and the grinding wheel spindle. It is difficult to achieve high-precision detection due to factors such as large moment of inertia. In terms of the grinding process of shaft parts, there is currently no method for detecting the grinding force of the grinding wheel with a simple principle, a reasonable scheme, and high precision.

Contents of the invention

The purpose of the present invention is to provide a method for detecting grinding wheel grinding force in the processing of shaft parts in view of the shortcomings of existing grinding force detection methods in shaft part grinding machine tools, thereby eliminating the need for grinding force detection on special load cells Dependence, to realize the accurate detection of the normal grinding force and tangential grinding force of the grinding wheel during the processing of shaft parts, and at the same time achieve the purpose of simplifying the hardware structure of the grinding machine and improving the flexibility of the system.

Technical scheme of the present invention is as follows:

A method for detecting the grinding force of a grinding wheel during machining of a shaft part, characterized in that: firstly, detecting and recording the motor current signal and position signal during the execution of a grinding program without feed, and calculating and obtaining the drive motor of the grinding wheel feed shaft According to the distribution law of the electromagnetic thrust and electromagnetic torque signals of the drive motor of the workpiece rotation axis, the friction force of the machine tool movement pair and the sum of the acceleration and deceleration forces in the direction of workpiece rotation and the direction of grinding wheel feed are obtained and regarded as the reference signal value. In the process, the measured and calculated electromagnetic thrust and electromagnetic torque signals of the drive motor of the grinding wheel feed shaft and the drive motor of the workpiece rotation axis are subtracted from the corresponding reference signal values to obtain the corresponding grinding force signal of the grinding wheel. The electromagnetic thrust signal of the feed shaft driving motor mainly corresponds to the normal grinding force of the grinding wheel, and the electromagnetic torque signal of the workpiece rotating shaft driving motor mainly corresponds to the tangential grinding force of the grinding wheel.

The specific method of the present invention is as follows: the current detection device is used to measure the winding current signal of the grinding wheel feed shaft driving motor and the winding current signal of the workpiece rotating shaft driving motor; the encoder module is used to respectively detect the linear position of the grinding wheel feeding shaft driving motor and the workpiece rotating shaft The angular position of the driving motor; input the current signal and position signal into the grinding force detection control device, and establish a synchronous rotating coordinate system based on the linear position of the driving motor winding of the grinding wheel feed axis and the angular position signal of the workpiece rotating shaft driving motor. In the synchronous rotating coordinate system Calculate the instantaneous torque current values of the two drive motor windings respectively, and obtain the instantaneous electromagnetic thrust and electromagnetic torque of the grinding wheel feed axis drive motor and the workpiece rotation axis drive motor through the torque constant; use the same process parameters to perform processing without feed program, and record the distribution of the electromagnetic thrust and electromagnetic torque signals of the driving motor during program execution; in the actual grinding process, the recorded electromagnetic thrust and electromagnetic torque signals are used as reference values, and the electromagnetic thrust and electromagnetic torque obtained by actual collection and calculation The corresponding grinding force signal of the grinding wheel can be obtained by subtracting the torque signal from the reference value. According to the structural characteristics of the shaft parts grinding machine tool, the electromagnetic thrust signal of the drive motor of the grinding wheel feed shaft mainly corresponds to the normal grinding force of the grinding wheel, and the drive motor of the workpiece rotation axis The electromagnetic torque signal mainly corresponds to the tangential grinding force of the grinding wheel.

The invention makes full use of the direct coupling relationship between the electromagnetic thrust of the grinding wheel feed shaft driving motor and the normal grinding force of the grinding wheel in the shaft part grinding machine tool, and the direct coupling between the electromagnetic torque of the workpiece rotating shaft driving motor and the tangential grinding force of the grinding wheel By detecting the current of the motor winding and observing its electromagnetic thrust and electromagnetic torque signals, the indirect detection of the grinding force of the grinding wheel is realized, thus avoiding the use of multi-axis force sensors and rotating dynamometers. This simplifies the hardware scheme of the grinding force detection device and maintains the integrity of the original structure of the grinding machine tool. The present invention obtains the friction force of the machine tool movement pair in the direction of workpiece rotation and the direction of grinding wheel feed, and the sum of the acceleration and deceleration forces by recording the distribution law of the electromagnetic thrust and electromagnetic torque signals of the drive motor during the execution of the processing program without feeding. As a reference signal, in the actual processing process, the measured and calculated electromagnetic thrust and electromagnetic torque signals of the drive motor are subtracted from the reference value to realize the effective separation of friction, acceleration and deceleration forces and other interference factors, so as to obtain accurate grinding wheel Grinding force signal. The grinding force detection method provided by the invention does not need to change the original structure of the grinding machine tool, so it has positive effects on cost control, reliability assurance and the like.

The invention is simple in principle, reasonable in scheme and high in precision, and is suitable for the detection of grinding force and the monitoring of the state of the processing technology during the grinding process of shaft parts with various specifications.

Description of drawings

Accompanying drawing is schematic diagram of the present invention.

Detailed ways

The specific embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings.

As shown in the figure, there are a workpiece 1 and a grinding wheel spindle support 11 on the guide rail of the machine tool base 5, the grinding wheel spindle support 11 is equipped with a grinding wheel 2, the workpiece has a workpiece rotation shaft drive motor 4, and the grinding wheel 2 has a grinding wheel feed drive motor 3 , the workpiece rotating shaft drive motor 4 has a winding current detection unit 1 6 and a rotation angle encoder module 7, the grinding wheel feed drive motor 3 has a winding current detection unit 2 8 and a linear position encoder module 9, and a winding current detection unit 1 6 and the rotation angle encoder module 7, the winding current detection unit 2 8 and the linear position encoder module 9 are connected to the grinding force detection control unit 10. The workpiece 1 illustrated in the present invention is a shaft part, a method for detecting the grinding wheel grinding force in the machining process of the shaft part, which specifically adopts the following steps:

A. Use the winding current detection unit 28 to measure the current signal of the grinding wheel feed shaft drive motor 3; use the winding current detection unit 1 6 to measure the current signal of the workpiece rotation shaft drive motor 4;

B. Use the linear position encoder module 9 to detect the linear position of the grinding wheel feed shaft drive motor 4; use the rotary angle encoder module 7 to detect the angular position of the workpiece rotation shaft drive motor 3;

C, the grinding force detection control unit 10 establishes a synchronous rotating coordinate system based on the linear position of the grinding wheel feed shaft drive motor 4 and the angular position signal of the workpiece rotary shaft drive motor 3 collected by the linear position encoder module 9 and the rotation angle encoder module 7, In the synchronous rotating coordinate system, calculate the instantaneous values of torque currents of the two drive motors respectively, and obtain the instantaneous electromagnetic thrust and electromagnetic torque of the grinding wheel feed shaft drive motor 4 and the workpiece rotation shaft drive motor 3 through the torque constant;

D. Use the same process parameters to execute the processing program without feed first, and record the distribution of the electromagnetic thrust and electromagnetic torque signals of the driving motor during the program execution process;

E. In the actual grinding process, the recorded electromagnetic thrust and electromagnetic torque signals are used as reference values, and the corresponding grinding wheel grinding force can be obtained by subtracting the actual collected and calculated electromagnetic thrust and electromagnetic torque signals from the reference values. Signal. Wherein, the electromagnetic thrust signal of the grinding wheel feed shaft driving motor 4 mainly corresponds to the normal grinding force of the grinding wheel, and the electromagnetic torque signal of the workpiece rotating shaft driving motor 3 mainly corresponds to the tangential grinding force of the grinding wheel.

The winding current detection unit 1 6 and the winding current detection unit 2 8 of the present invention can be realized by using a precision four-wire shunt resistor and an isolated operational amplifier circuit.

Claims (3)

1. the wheel grinding power detection method in an axle part process, it is characterized in that: at first detection record is not with motor current signal and the position signalling of grinding program process under the feeding condition, calculate and obtain emery wheel feed shaft drive motors and workpiece rotating shaft drive motors electromagnetic push and electromagnetic torque signal distributions rule, obtain the machine tool motion friction force of workpiece direction of rotation and emery wheel direction of feed, plus-minus turn of speed summation is also regarded it as reference signal value, in actual Grinding Process, to measure, the electromagnetic push and the electromagnetic torque signal that calculate gained emery wheel feed shaft drive motors and workpiece rotating shaft drive motors subtract each other with corresponding reference signal value, can obtain corresponding wheel grinding force signal, the main corresponding grinding wheel normal grinding force of its medium plain emery wheel feed shaft drive motors electromagnetic push signal, the main corresponding emery wheel tangential grinding force of workpiece rotating shaft drive motors electromagnetic torque signal.

2. the wheel grinding power detection method in a kind of axle part process according to claim 1, is characterized in that: adopt current sensing means to measure respectively emery wheel feed shaft drive motors winding current signal and workpiece rotating shaft drive motors winding current signal; Adopt coder module to detect respectively emery wheel feed shaft drive motors linear position and workpiece rotating shaft drive motors angle position; By current signal and position signalling input grinding force detection control apparatus, set up synchronous rotating frame based on emery wheel feed shaft drive motors winding linear position and workpiece rotating shaft drive motors angle position signal, calculate respectively the torque current instantaneous value of two drive motors windings in synchronous rotating frame, and obtain transient electromagnetic thrust and the electromagnetic torque of emery wheel feed shaft drive motors and workpiece rotating shaft drive motors by torque constant; Adopt the same process parameter first to carry out and be not with the feeding procedure, and logging program implementation drive motors electromagnetic push and electromagnetic torque signal distributions; Take in actual Grinding Process electromagnetic push and the electromagnetic torque signal recorded is reference value, by actual acquisition, calculate gained electromagnetic push and electromagnetic torque signal and reference value and subtract each other and can obtain corresponding wheel grinding force signal, according to axle part grinding machine design feature, the main corresponding grinding wheel normal grinding force of emery wheel feed shaft drive motors electromagnetic push signal, the main corresponding emery wheel tangential grinding force of workpiece rotating shaft drive motors electromagnetic torque signal.

3. the wheel grinding power detection method in a kind of axle part process according to claim 2 is characterized in that: described winding current detecting unit adopts accurate four-wire system shunt resistance and isolation operation amplifier circuit to realize.