WO2011035498A1

WO2011035498A1 - Rolling linear guide rail pair friction force dynamic detecting device and method thereof

Info

Publication number: WO2011035498A1
Application number: PCT/CN2009/074332
Authority: WO
Inventors: 张合; 李春梅; 冯虎田; 韩军; 殷爱华; 陶卫军; 欧屹; 赵江杰
Original assignee: 南京理工大学
Priority date: 2009-09-22
Filing date: 2009-09-30
Publication date: 2011-03-31
Also published as: CN101660957A

Abstract

A rolling linear guide rail pair friction force dynamic detecting device and method thereof are provided. The device comprises a body, a servo motor (1), a bench (2), a lead screw (3), rolling linear guide rails (4), a slider (5), an S-shaped tension sensor (6), a forward limit switch (7), a reverse limit switch (8), a moving control card (9) and a control panel (10) etc. The detecting method based on the said device comprises the following steps: firstly, setting parameters; and then carrying out the loaded running on the guide rail pair to be measured, measuring the friction force dynamically and analyzing the measured data; finally, saving and printing the measured data and the result, giving a qualification evaluation, and ending the measuring process. The method according to the present invention can display the distribution of the data measured dynamically on a computer in real-time, compute the maximum, the minimum and the mean value thereof, and compare them with the design standards of corresponding products to evaluate its qualification.

Description

Rolling linear guide pair friction force dynamic detecting device and detecting method thereof

The invention belongs to the technical field of friction force dynamic detection, in particular to a rolling linear guide pair friction force dynamic detecting device and a detecting method thereof. Background technique

The rolling linear guide pair is generally composed of a guide rail, a slider, an inverter, a rolling body and a retainer. It is a new type of rolling support for reciprocating linear motion, which can replace the rolling of the steel ball between the slider and the guide rail. Direct sliding contact, and the rolling element can achieve an infinite loop in the raceway and slider by means of the reverser. The rolling linear guide pair has the advantages of small friction coefficient, high running precision, no creep, wear resistance, high rigidity and small thermal deformation, and is widely used as a guiding part for high-precision CNC machine tools and machining centers. The frictional force directly reflects the service life, bearing capacity and motion accuracy of the guide rail pair. because:

(1) The frictional heat causes the deterioration of the lubrication condition of the guide rail; (2) The friction radius causes the increase of the groove radius, which causes the contact state to change; (3) The friction caused by the friction causes the fatigue damage of the steel ball surface and the groove surface, affecting Service life.

The friction measurement of the rolling linear guide pair is an important part of the rolling linear guide pair detection. It can directly reflect the processing and assembly status of the guide rail pair and contribute to the process analysis. Compared with static measurement, dynamic measurement has the characteristics of high measurement accuracy, good repeatability, high efficiency and high degree of inspection automation. It has become the development trend of rolling linear guide pair friction measurement.

At present, the dynamic measurement of the friction of the rolling linear guide pair is mainly performed by specially manufactured measuring equipment. The measurement principle generally adopts the indirect comparison method, that is, the driving device drives the guide rail sub-slider to run at a constant speed. According to Newton's classical mechanics law, it can be known that the driving force F is equal to the dynamic friction force of the guide rail pair. The data is collected by a force sensor mounted on the sub-slider of the guide rail, and the dynamic friction of the guide rail pair is obtained after the conversion.

The world's famous rolling linear guide manufacturers, such as Japan's NSK, TSK, Sweden's SKF, etc., have advanced rolling linear guide pair friction professional testing equipment to provide testing guarantee for its product quality. However, due to technical blockade, detailed materials are not available. In China, the dynamic detection of the frictional force of the rolling linear guide has also achieved a lot of development. Tao Zhengsu, Yin Xianghong, and Cai Xiaofeng disclosed a rolling linear guide integrated tester in the article "Development of a Linear Rolling Guide Tester", which uses a wire rope traction slider to move a rolling linear guide. Friction is detected, but the elasticity of the wire rope itself in the tester can result in inaccurate measurement. Xiong Jun is in the Roll Research on the principle and method of dynamic comprehensive detection of frictional and motion accuracy of linear guides. The paper discloses a dynamic comprehensive test device for the precision and friction of rolling linear guides. The loading device is not considered in the test device. The screw is driven by a stepping motor. The working principle is to control the slider to move at a constant speed. Due to the friction, the speed will fluctuate, and the stepping motor has no feedback control, and the uniform speed control cannot be achieved. Therefore, the friction measured by the test device is not very accurate. Yin Xuejun and Liu Jingyan published a research method on the frictional force of rolling guides in the article "Experimental Research on the Dynamic Friction of HTSD Linear Rolling Guides". The method is to fix the guide rails on the milling table, and the table is at a certain speed. The guide rail moves at a constant speed, and the slider, force sensor, clamp and milling spindle remain stationary. The use of the rail movement method will limit the length of the rail to be tested, so there are certain limitations in application. Summary of the invention

The technical problem to be solved by the present invention is to provide a detecting device capable of real-time dynamic detection of a rolling linear guide pair dynamic friction force and a detecting method thereof.

The technical solution for achieving the object of the present invention is: a rolling linear guide pair friction force dynamic detecting device, including a bed body, a servo motor, a table, a female screw rod, a rolling linear guide, a slider, an S-type tension sensor, and a positive direction Limit switch, reverse limit switch, motion control card, control panel, printer, industrial computer, data acquisition card, load cell; servo motor and rolling linear guide fixed to the bed, rolling linear guide is two parallel straight lines The guide rail, the positive limit switch and the reverse limit switch are respectively located at two ends of each guide rail of the rolling linear guide and are fixed on the bed; the slider can slide freely on the rolling linear guide, and each linear guide is provided with a slider The middle of the workbench is fixed on the nut matched with the female screw. The load cell is disposed between the workbench and the slider, and the two are connected. One end of the S-type tensile sensor is fixed to the side of the workbench. The other end of the S-type tension sensor is connected to the slider; the output of the above sensor and the limit switch is connected to the data acquisition card The data acquisition card is connected with the first data end of the industrial computer, and the collected sensor signal is sent to the industrial computer for processing, and the second data end of the industrial computer is connected with the recorder to complete the function of printing and recording, and the third data of the industrial computer The end is connected to the input end of the motion control card, and transmits the motion speed and direction control signal to the motion control card, and the fourth data end of the industrial computer is connected to the serial port end of the control panel to complete the interaction function of the status signal and the operation instruction; the motion control card The output is connected to the servo motor, and the received control signal is transmitted to the servo motor to control the operation of the servo motor.

A method for detecting a rolling linear guide pair friction force dynamic detecting device comprises the following steps: Step 1: setting a sub-parameter of the measured rail on the industrial computer, the parameters include: a rail sub-number, a pre-load, a rail length, a rail precision level, Rail slide structure form, measuring speed, friction test Range of magnitude changes;

Step 2: Load and run the tested guide rail pair to improve the machining surface appearance of the guide rail, so that the cooperation between the slider and the guide rail is stabilized, and finally the guide rail pair enters a stable working state; Step 3: Friction Force to make dynamic measurements;

Step 4: Analyze the measurement data in step 3 and save the analysis result;

Step 5: Save and print the test data and results, give a qualification judgment, and end the measurement process.

Compared with the prior art, the invention has the significant advantages: 1) The method of the invention can display the distribution of the dynamic measurement data through a computer in real time, and calculate the maximum value, the minimum value and the mean value, and the design standard of the corresponding product. The comparison is made to determine whether it is qualified or not. Compared with the static detection method currently used, it has the advantages of high efficiency, high stability and high reliability. 2) The S-type tension sensor can withstand the pull, pressure and output. The symmetry is good, the precision is high, and the structure is compact. The detection method can realize the high-precision detection of the dynamic friction force of the ball linear guide pair. The basic experiment based on this method proves that the detection method can meet the testing requirements of the production enterprise; 3) The invention relates to a rolling linear guide pair dynamic friction detecting device which has a simple structure, is convenient for processing and production, and has accurate and reliable data values, and has a good market prospect.

The invention is further described in detail below with reference to the accompanying drawings. DRAWINGS

1 is a schematic structural view of a rolling linear guide pair dynamic friction detecting device according to the present invention.

2 is a test principle diagram of a rolling linear guide pair dynamic friction detecting device of the present invention.

3 is a front view of the sensor connection of the rolling linear guide pair dynamic friction detecting device of the present invention. 4 is a left side view of the sensor connection of the rolling linear guide pair dynamic friction detecting device of the present invention. FIG. 5 is a flow chart of a method for detecting dynamic friction force of a rolling linear guide pair according to the present invention.

FIG. 6 is a flow chart of loading and running in the method for detecting the dynamic friction of the rolling linear guide pair according to the present invention. 7 is a flow chart of dynamic measurement in a method for detecting a dynamic friction force of a rolling linear guide according to the present invention. FIG. 8 is a flow chart of data analysis in the method for detecting the dynamic friction force of the rolling linear guide pair according to the present invention. Figure 9 is a graph showing the mean value deviation of the measured value of the inner rail in the embodiment.

Figure 10 is a graph showing the mean value deviation of the measured value of the outer rail in the embodiment.

Figure 11 is a spectrum analysis diagram of the inner rail in the embodiment.

Figure 12 is a spectrum analysis diagram of the outer rail in the embodiment.

Description of the symbols 1 servo motor 2 workbench

3 female screw 4 rolling linear guide

5 Slider 6 S-type tension sensor

7 Reverse limit switch 8 Positive limit switch

9 Motion Control Card 10 Control Panel

11 Recorder 12 IPC

13 Data acquisition card 14 Load cell

15 connecting rod 16 block concrete embodiment:

1 and 2, the rolling linear guide pair dynamic friction detecting device of the present invention comprises a bed, a servo motor 1, a table 2, a female screw 3, a rolling linear guide 4, a slider 5, and an S-type tension sensor 6. , positive limit switch 7, reverse limit switch 8, motion control card 9, control panel 10, printer 11, industrial computer 12, data acquisition card 13, load cell 14, link 15, pad 16; As a whole cast iron part, the servo motor 1 and the rolling linear guide 4 are fixed on the bed body, the rolling linear guide 4 is two parallel linear guides, and the forward limit switch 7 and the reverse limit switch 8 are respectively located on the rolling linear guide 4 The two ends of each rail are fixed on the bed; the slider 5 can slide freely on the rolling linear guide 4, and two sliders are arranged on each linear guide, a total of four sliders, and the middle portion of the table 2 is fixed The nut of the female screw 3 is matched with the nut; in combination with FIG. 3 and FIG. 4, the load cell 14 is disposed between the table 2 and the slider 5, and the two are connected, and one end of the S-type tension sensor 6 passes through the screw. Connected to the side surface of the table 2, the other end of the S-type force sensor 6 is connected via a link 15 and the pad 16 of the slider 5, the load cell 14 and the number of S-type force sensor 6 are each four;

The output end of the sensor and the limit switch is connected to the data acquisition card 13, and the data acquisition card 13 is connected to the first data end a of the industrial computer 12, and the collected sensor signal is sent to the industrial computer 12 for processing, and the second of the industrial computer 12 The data terminal b is connected to the recorder 11 to complete the function of printing and recording. The third data terminal c of the industrial computer 12 is connected to the input end e of the motion control card 9, and transmits the motion speed and direction control signals to the motion control card 9. The fourth data end d of the industrial computer 12 is connected to the serial port end i of the control panel 10 to complete the interaction function of the status signal and the operation command; the output end f of the motion control card 9 is connected with the servo motor, and transmits the received control signal to The servo motor controls the operation of the servo motor 1.

The guide rail 4 is fixed on the bed body, and the work table 2 is mounted on the nut mated with the female screw rod 3; the industrial control machine 12 controls the servo motor 1 to drive the rotation of the female lead screw 3 through the motion control card 9 to match the female screw rod 3 The combined nut drives the table 2 to move forward along the guide rail 4. The table 2 drives the sub-slider 5 of the tested rail to move at a uniform speed through the S-type tension sensor 6; when moving to the end of one side of the guide rail, the data acquisition card is collected. The signal of the limit switch 7 or 8 is transmitted to the industrial computer 12, and the industrial computer 12 controls the servo motor 1 to reverse by the motion control card 9, and drives the table 2 to move in the opposite direction along the guide rail 4. During this process, the data acquisition card continuously collects the friction signal obtained by the S-type tension sensor and transmits it to the computer system for data processing.

A method for detecting dynamic friction force of a rolling linear guide pair firstly performs preparatory work before sampling, and sets initial parameters of the detecting device to determine basic parameters of the linear guide to be tested. Before the friction measurement is performed, the linear guide pair is loaded and tested to ensure the dynamic performance of the linear guide pair is in a stable state to ensure the stability of the test state. When measuring, the servo motor 1 drives the female screw. 3 Rotate to drive the table 2. The axial movement along the guide rail 4 is carried out by the table 2 through the S-type tension sensor 6 to drive the sub-slider 5 to be measured. Then the force applied by the S-type tension sensor 6 is equal to the friction force of the slider 5 when moving at a constant speed. The data acquisition card 13 collects the S-type tension sensor at a certain sampling frequency. 6 The signal obtained when the slider 5 is moved is transmitted to the industrial computer 12. The industrial computer 12 analyzes and processes the collected signals to calculate the frictional force data of the slider 5 as it moves along the guide rail 4. Since the working part of the rolling linear guide in the actual application is mainly in the middle section of the guide rail, and the servo motor is not in stable operation at the beginning of the measurement, the stability of the system will be affected, so the measurement data should be screened. The beginning and end of the measurement curve are deleted, and only the measurement data of the intermediate working section of the guide rail is taken for analysis. The distribution of the selected data is displayed in real time by the industrial computer, and its maximum, minimum and mean values are calculated and compared with the design criteria of the corresponding products to determine whether they are qualified. At the same time, the corresponding spectrum analysis can be performed on the collected data. Referring to FIG. 5, the following steps are specifically included:

Step 1: Set the sub-parameters of the measured rail. The parameters include: rail sub-number, pre-load, rail length, rail accuracy grade, rail slider structure, measurement speed, and friction force measurement range;

Step 2: Load and run the test on the tested rail pair, set the running speed, make the dynamic performance of the linear guide pair in a stable state, and ensure the stability of the test state. The loading and running is to simulate the working condition of the rolling linear guide pair under load. Generally, the dynamic frictional force measurement is performed on the linear guide pair after running for more than 30 minutes. Through the running and running, the machining surface of the guide rail can be improved, the cooperation between the slider and the guide rail is stabilized, and the guide rail pair enters a stable working state, so that the measured data can be closer to the data under actual working conditions.

When loading and running, a certain load is pre-applied on the slider 5 of the rolling linear guide 4, and the load force is measured by the load cell 14 and recorded, and the running direction, the running number and the number of motor revolutions are set; According to the set running speed judgment system should be set to normal mode or deceleration mode; then start running in accordance with the set parameters. The industrial computer 12 and the operation control panel 10 with the single chip as the core can control the operation of the servo motor 1. The industrial computer 12 and the control panel 10 use serial communication to realize the transmission of the control signal. The motion control card 9 receives the motion command from the industrial computer 12 or the control panel 10, that is, by controlling the AC servo motor 1 to drive the mother screw 3 to move the table 2 (nut). The table 2 moves the slider 5 along the linear guide 4 through the S-type tension sensor 6, and the forward limit switch 8 determines whether the forward motion is completed. If it is completed, the reverse motion is performed, and then the reverse limit switch 7 judges Whether the reverse movement is completed, if it is completed, it is judged whether the running and the number of times are reached, and when it is completed, it is transferred to stop running, and if it is not completed, the running and closing process is continued. Combined with Figure 6, the specific steps are:

2.1, applying a load on the workbench, measuring the load force by the load cell 14 and recording;

2.2. Input motion parameters, including: initial direction of running, number of running times and motor speed, motor speed is 50rpm to 2000rpm;

2.3. Determine the set motor running speed. If it is not greater than 400 rpm, enter the normal running mode. If the motor speed is greater than 400 rpm and less than or equal to 2000 rpm, enter the deceleration mode. If the motor speed is greater than 2000 rpm, the motor speed is out of bounds. Return to step 2.2 to reset;

2.4. According to the judgment result of 2.3, in the normal operation mode, start running in accordance with the set parameters; the data of the positive limit switch 8 is continuously detected by the data acquisition card 13, and the signal is continued without the signal, and the signal is positive. The motion has been completed, and the motion is reversed. The data of the reverse limit switch 7 is continuously detected by the data acquisition card 13. If there is no signal, the motion continues, and if there is a signal, the reverse motion is completed; then it is judged whether the run and the number of times are reached. If the number of running matches is reached, go to step 2.5; if the number of running times is not reached, continue with this step. In the deceleration mode, start running in accordance with the set parameters; use the breakpoint deceleration function to move to the set motion speed; the data acquisition card 13 continuously detects the signal of the positive limit switch 8, and the signal continues to move without the signal. , if there is a signal, the forward motion has been completed, and the motion is reversed; the breakpoint deceleration function is used to move to the set motion speed; the data acquisition card 13 continuously detects the signal of the reverse limit switch 7, and the signal continues to move without the signal. If there is a signal, the reverse motion has been completed; then it is judged whether the running and the number of times have been reached, and the number of running times is transferred to step 2.5; if the running number is not reached, the step is continued.

2.5, stop running: The motor number is automatically stopped when the set number of running times is reached, or there is a special case. The stop button is triggered to stop the motor movement.

Step 3: Dynamically measure the friction; first input the auxiliary parameters of the guide rail: including preload, guide rail length, guide rail accuracy grade, measurement speed, and friction force measurement range; determine whether it is at the measurement starting point, if not at the measurement starting point, The industrial computer 12 sends a signal to the motion control card 9 to drive the servo The motor 1 drives the table 2 to move to the measurement starting point; the motion control card 9 receives the motion command from the industrial computer 12 or the control panel 10, that is, by driving the AC servo motor 1 to drive the mother screw 3 to move the table 2 (nut). The table 2 is pulled by the S-type tension sensor 6 to move the slider 5 along the linear guide 4 at a uniform speed. At this time, the tension sensor 6 collects the dynamic friction force signal of the real-time rolling linear guide pair, and is sent to the multifunctional data collection after filtering. The card 13 displays the frictional dynamic measurement curve in real time on the display of the industrial computer 12. When the workbench 2 completes a standard measurement, the forward limit switch 8 is triggered, and then a signal is sent to the industrial computer 12 to stop the data acquisition and the operation of the servo motor 1. The measurement data is stored in the online data file, and finally the industrial computer 12 analyzes and processes the collected data to determine whether the guide rail pair is qualified or not, and the test report is printed by the recorder 11 to store the measurement data in the database. The data file can be displayed online and the data is filtered and analyzed. The measurement data is stored in the database for later browsing. When the forward measurement is completed, it is judged whether the reverse measurement is performed. If yes, the reverse measurement is performed. Otherwise, the step is ended. Referring to Figure 7, specifically:

3.1, guide rail sub-parameter input: including pre-loading, rail length, rail accuracy grade, measuring speed, friction force measurement range variation range parameter input;

3.2, judging whether it is at the starting point of the measurement, if not at the starting point of the measurement, the industrial computer 12 sends a signal to the motion control card 9 to drive the servo motor 1 to drive the table 2 to move to the measurement starting point;

3.3, start data collection, use data acquisition card 13 to collect data;

3.4. Draw a measurement curve in real time on the industrial computer 12;

3.5. Stop the measurement: After completing a measurement, it will stop automatically at the corresponding limit switch, or the manual will stop the measurement;

3.6. Save the data in an online data file;

3.7. Display the above data files on the computer in real time and filter and analyze the data, delete the beginning and end of the measurement curve, and only take the measurement data of the middle working section of the guide rail for analysis; The head and tail are mainly used for installation and positioning. The working part is mainly in the middle section of the guide rail. At the same time, the servo motor is not in stable operation at the beginning, which will affect the stability of the system. Therefore, the measurement data should be filtered. The first and last part of the measurement curve are deleted, and only the measurement data of the middle working section of the guide rail is taken for analysis. This is more reasonable and meets the actual use requirements. When analyzing the measurement data, it is as follows: Calculate the peak value, mean value, and average of the measurement data. The variance is then displayed on the industrial computer display.

3.8. Save the filtered data to the database for later browsing queries;

3.9, print out the report;

3.10. After the forward measurement is completed, judge whether to perform the reverse measurement. If yes, go to step 3.2. Otherwise, End.

Step 4: Analyze the measurement data in step 3 and save the analysis result; combined with Figure 8, the specific:

4.1. Reading measurement data from the database;

4.2. Calculate the peak value and mean value of the measured data;

4.3. Display the calculation result of step 4.2 on the display of the industrial computer 12;

4.4. Perform spectrum analysis on the data in step 4.1 by using a fast Fourier transform (FFT) algorithm;

4.5. Display the spectrum analysis diagram on the industrial computer 12 display;

4.6. Save the analysis results.

The data management module in the main program mainly records the measurement data and the analysis results, and provides the query of the historical data (you can choose to query by model, query by number, query by time), delete and printout. It comprehensively measures the information database, and is responsible for storing various structural parameters, measurement time, conditions and measurement results of the measuring guide pair; personnel database, storing the inspector, inspector and auditor; standard database, storing the measurement standard of each type of guide rail pair Model database, storage of each series of rail sub-models.

The present invention will be further described in detail below with reference to the embodiments: Table 1 is a scroll line of the present invention

Table 1 Table 2 is a technical parameter of the S-type tension sensor in the rolling linear guide pair dynamic friction detecting device of the present invention.

Table 2

Table 3 is a technical parameter table of the load cell in the rolling linear guide pair dynamic friction detecting device of the present invention.

table 3 The dynamic measurement process of the friction force of the HJG-D series DA35AL type rolling linear guide pair produced by a manufacturer by the method proposed in the present invention is as follows:

Step 1: Set the sub-parameters of the measured rail. The parameters include: Rail sub-number S006-08-02-14A, pre-loading ^ ₂ level, rail length 3000mm, rail accuracy grade 3, rail slider structure is lengthened The type of double slide and friction measurement range is 14N ± 25 %.

Step 2: Load and run the tested rail pair;

A certain load is pre-loaded on the slider 5 of the linear guide 4, and the load force is measured by the load cell 14 to be 3300 N and recorded, and the running direction is set to be forward, the running number is 200 times, and the running speed is 2000 rpm. For the rolling linear guide pair high speed loading run.

Step 3: Dynamic measurement of friction;

The single measurement mode is selected, the measurement direction is positive (from left to right), and the measurement speed is 100 rpm. The measurement data is acquired by an S-type tension sensor 6 mounted on the two sliders 5 of the rolling linear guide pair 4. Because the head and tail of the rolling linear guide pair are mainly used for installation and positioning in practical applications, the working part is mainly in the middle section of the guide rail. At the same time, the servo motor is not in stable operation at the beginning, which will affect the stability of the system. The measurement data is screened. The beginning and end of the measurement curve are deleted, and only the measurement data of the intermediate working section of the guide rail is selected.

Step 4: Analyze the measurement data in step 3;

If the obtained dynamic measurement curve of friction is stable, the statistical calculation values are within the standard range, indicating that the processing and assembly of the rolling linear guide pair is good, and the contact surface roughness is appropriate to meet the frictional requirements. If the peak value and the mean value are too large, there may be a bump on the surface of the guide rail, a pre-tightening force between the guide rail and the slider, or an impurity in the contact groove; if it is too small, the slider and the guide rail are loosely connected, and the pre-tightening force is too Small; the measurement curve undulation may be caused by excessive surface roughness and wear of the guide rail. The problematic rolling linear guide pair should be reworked, the surface of the rail should be polished, the bumps removed or reassembled, and the measurement checked.

The measurement curve allows a fluctuation range of ±25 %. It can be seen from Fig. 9 and Fig. 10 that the two sets of measured values basically float around the mean value, and the change is relatively stable, and does not exceed the allowable fluctuation range. The sliders of the inner and outer guide rails are subjected to tensile force during measurement. The maximum/small value and mean deviation are shown in Table 4.

Table 4 Step 5: Save the records of measurement data and analysis results, provide query, delete and printout of measurement history data. When making a query, you can choose to query by model, query by number, and query by time.

Both sets of measurements are within the required specifications. The friction curve fluctuates less, the two sets of measurements are close to each other, and the measurement results are ideal. It shows that the machining and assembly of the guide rail pair is better and meets the measurement standards.

The spectrum analysis was performed on the two sets of data. The results are shown in Figure 11 and Figure 12:

As can be seen from the figure, the larger part of the two sets of measurements is concentrated between 0-2 Hz.

According to the analysis of the mechanism of the rolling linear guide pair, the frequency of the steel ball of the guide rail pair entering and exiting the raceway is:

2x 60xZ) where:

V-rail sub-slider moving speed (m/min), that is, table moving speed

One guide rail steel ball diameter (mm)

/ a steel ball passing frequency (Hz) (that is, the number of steel balls passed per unit time)

Workbench moving speed:

v = nx pxi (2 )

Where n is the AC servo motor speed, p is the ball screw lead connected to the motor, and i is the reduction ratio. The measuring speed is 100 rpm, the ball screw lead is 20 mm, and the reduction ratio i is 1/2. After calculation, the moving speed of the table is lm/min. The diameter of the steel ball of the DA35AL rolling linear guide pair is 5.25mm. Substituting the value into equation (1), the calculated value is 1.59 Hz, which is close to the 1.5 Hz peak of the peak appearing in Figs. 11 and 12. Considering that there is a gap between the steel balls in the raceway, the actual distance between the two adjacent steel balls is greater than D, so the measured value is less than the theoretical calculation.

It can be seen from the figure that the periodic in-and-out raceway of the rolling linear guide pair of steel balls has a great influence on the fluctuation of the friction force. It is considered to optimize the design of the secondary track of the guide rail, and select a reasonable reverser return curve and the radius of curvature of the return bead to reduce the impact of the steel ball entering and exiting the raceway and reduce the friction fluctuation.

The two sets of curves also have a peak near 1.6 Hz. This is close to the rotation frequency of the AC servo motor of the measuring system (100/60 = 1.67Hz), which should be caused by the periodic rotation of the servo motor affecting the measuring system. It can be considered that the addition of shock absorbing cushioning material has reduced the impact of servo motor operation on the system.

The peaks appearing at the beginning of the spectrogram and around 3 Hz and beyond may be the spin of the secondary steel balls of the guide rail and the mutual sliding friction, the waviness of the raceway surface, the mechanical vibration of the measuring system, and the rolling linear guide pair. And the measurement system processing assembly error and other factors. Through the above specific implementation examples, the method and apparatus of the present invention are implemented.

Dynamic detection of the frictional force of the HJG-D series ball linear guide.

Claims

Claim

1. A rolling linear guide pair friction force dynamic detecting device, comprising: a bed body, a servo motor [1], a table [2], a mother screw [3], a rolling linear guide [4], a slider [5], S-type tension sensor [6], positive limit switch [7], reverse limit switch [8], motion control card [9], control panel [10], printer [11], industrial computer [12], data acquisition card [13], load cell [14]; servo motor [1] and rolling linear guide [4] are fixed on the bed, rolling linear guide [4] is two parallel linear guides, positive The limit switch [7] and the reverse limit switch [8] are respectively located at both ends of each of the guide rails of the rolling linear guide [4] and are fixed on the bed; the slider [5] can be on the rolling linear guide [4] Free sliding, each slider is set on the linear guide, the middle of the table [2] is fixed on the nut with the female screw [3 top, the load cell [14] is set on the table [2] and slide Between the blocks [5], and connect the two, one end of the S-type tension sensor [6] is fixed to the side of the table [2], S-type tension sensing The other end of [6] is connected with the slider [5]; the output of the above sensor and the limit switch is connected to the data acquisition card [13], the data acquisition card [13] and the first data end of the industrial computer [12] [a] ] Connected, the collected sensor signal is sent to the industrial computer [12] for processing, the second data end [b] of the industrial computer [12] is connected with the recorder [11], and the function of printing and recording is completed, the industrial computer [12] The third data end [c] is connected to the input end [e] of the motion control card [9], and transmits the motion speed and direction control signal to the motion control card [9], the fourth data end of the industrial computer [12] [d] Connect the serial port [i] of the control panel [10] to complete the interactive function of the status signal and the operation command; the output [f] of the motion control card [9] is connected to the servo motor, and the received control signal will be received. It is transmitted to the servo motor to control the operation of the servo motor [1].

2. The rolling linear guide pair frictional force dynamic detecting device according to claim 1, wherein two sliders are arranged on each linear guide rail, and four sliders are arranged on the linear guide rail [4].

The rolling linear guide pair frictional force dynamic detecting device according to claim 1 or 2, wherein the other end of the S-type tension sensor [6] passes through the connecting rod [15] and the spacer [16] and the slider [5] connected.

The rolling linear guide pair frictional force dynamic detecting device according to claim 1 or 2, wherein the number of the load cell [14] and the S-type tension sensor [6] is four.

5. The rolling linear guide pair frictional force dynamics detecting apparatus according to claim 3, wherein the number of the load cell [14] and the S-type tension sensor [6] is four.

A method for detecting a rolling linear guide pair frictional force dynamic detecting device according to claim 1, comprising the steps of:

Step 1: Set the sub-parameters of the measured rail on the industrial computer [12]. The parameters include: rail sub-number, pre-load, rail length, rail accuracy grade, rail slider structure, measurement speed, friction force measurement range ;

Step 4: Analyze the measurement data in step 3 and save the analysis result;

The method for detecting the frictional force of the rolling linear guide by the frictional force according to claim 6, wherein the step 2 loading and running the measured rail pair comprises the following steps:

Step 2.1: Apply load to the rolling linear guide pair, measure the load force by the load cell [14] and record;

Step 2.2. Set the running and running parameters. The set parameters are: the running direction, the running number and the number of motor revolutions. The running motor number is 50 to 2000 rpm;

Step 2.3: judging the set motor running speed, if not more than 400 rpm, enter the normal running mode; if the motor speed is greater than 400 rpm and less than or equal to 2000 rpm, enter the deceleration mode; if the motor speed is greater than 2000 rpm, the motor speed is out of bounds , return to step 2.2 to reset;

Step 2.4: In the normal running mode and the deceleration mode, respectively run according to the set parameters; the forward limit switch determines whether the forward motion is completed, if completed, the reverse motion, and then the reverse limit The switch determines whether the reverse motion is completed. If it is completed, it is judged whether the running and the number of times are reached, and if it is completed, the process proceeds to step 2.5, and if it is not completed, the step is performed again;

Step 2.5, stop running: The number of running times that have reached the set is automatically stopped or the running stop switch is stopped to stop the motor movement.

8. The method for detecting a frictional force of a rolling linear guide according to claim 6, wherein the step (3) of dynamically measuring the friction force comprises the following steps:

Step 3.1, guide rail sub-parameter input: including pre-load, rail length, rail accuracy grade, Measuring speed and frictional force measurement range parameter input;

Step 3.2: Determine whether it is at the starting point of measurement. If it is not at the starting point of measurement, the industrial computer [12] sends a signal to the motion control card [9] to drive the servo motor [1] to drive the table [2] to the measurement starting point;

Step 3.3, start data collection, use the data acquisition card [13] to collect data;

Step 3.4. Draw a measurement curve in real time on the industrial computer [12];

Step 3.5: Stop the measurement: After completing a measurement, stop automatically at the corresponding limit switch, or manually stop the measurement;

Step 3.6. Save the data in an online data file;

Step 3.7. Display the above data file in real time on the industrial computer [12] and filter and analyze the data, delete the beginning and end of the measurement curve, and take only the measurement data of the intermediate working section of the guide rail for analysis;

Step 3.8: The filtered data is stored in the database for later browsing query;

Step 3.9, print out the report;

Step 3.10. After the forward measurement is completed, judge whether to perform reverse measurement. If yes, go to step 3.2, otherwise end.

The method for detecting the frictional force of the rolling linear guide according to claim 8, wherein the step 3.7 analyzes the measured data as follows: calculating the peak value and the mean value of the measured data, and then displaying on the industrial computer [12] The calculation results are displayed on the top.

10. The method for detecting a frictional force of a rolling linear guide according to claim 6, wherein the step 4 includes the following steps when analyzing the measurement data:

Step 4.1: Read measurement data from the database;

Step 4.2: Calculate the peak value and the mean value of the measured data;

Step 4.3: Display the calculation result of step 4.2 on the display of the industrial computer [12];

Step 4.4: Perform spectrum analysis on the data in step 4.1 by using the fast Fourier transform algorithm; Step 4.5, display the spectrum analysis diagram on the display of the industrial computer [12];

Step 4.6. Save the analysis results.