CN109556778B - Current-based ball screw pair pretightening force on-line monitoring method - Google Patents
Current-based ball screw pair pretightening force on-line monitoring method Download PDFInfo
- Publication number
- CN109556778B CN109556778B CN201811490353.9A CN201811490353A CN109556778B CN 109556778 B CN109556778 B CN 109556778B CN 201811490353 A CN201811490353 A CN 201811490353A CN 109556778 B CN109556778 B CN 109556778B
- Authority
- CN
- China
- Prior art keywords
- ball screw
- screw pair
- pretightening force
- current
- servo motor
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L5/00—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes
- G01L5/0061—Force sensors associated with industrial machines or actuators
- G01L5/0076—Force sensors associated with manufacturing machines
Abstract
The invention discloses a current-based ball screw pair pretightening force on-line monitoring method, which is characterized in that the pretightening force of a ball screw pair is degraded due to the abrasion of a raceway in the working process of the ball screw pair, and the axial rigidity of the ball screw pair is reduced due to the degradation of the pretightening force, so that the positioning precision of the ball screw pair is influenced. In order to conveniently and rapidly monitor the degradation process of the pre-tightening force, the invention determines the friction torque of the ball screw pair required to be overcome by the driving motor to drive the ball screw pair to rotate at the constant speed by monitoring the driving current of the driving motor under the constant-speed no-load working condition of the ball screw pair on line, and then calculates the pre-tightening force of the ball screw pair according to the relation between the friction torque and the pre-tightening force. The monitoring method can accurately and conveniently evaluate the abrasion and the pre-tightening state of the ball screw pair and predict the pre-tightening force degradation trend by regularly monitoring the obtained motor current signal under the constant-speed no-load state under the condition of not influencing the normal working condition of the ball screw pair.
Description
Technical Field
The invention discloses a current-based ball screw pair pre-tightening force on-line monitoring method, and belongs to the technical field of ball screw pair detection.
Background
The ball screw pair can convert rotary motion into linear motion and bear radial pressure, so that the ball screw pair has a large number of applications in industrial production, and relates to a plurality of fields such as numerical control processing, 3D printing, robot motion and the like. Because of its positioning accuracy and high running accuracy, it has a great deal of application in precision sports.
The ball screw pair is used as a key part in various precision instruments such as a numerical control machine tool, a precision instrument and the like, and the transmission efficiency, the transmission precision, the synchronism and the like of the ball screw pair are very important indexes. For the current high speed, high precision and high load ball screw by-product, precision retention is critical. Therefore, the precision retentivity monitoring of the ball screw pair in the actual operation process is the premise of ensuring the accurate work of the ball screw pair.
In the actual operation process, the abrasion of the balls generated in the rotation process influences the movement precision of the balls, so that the monitoring of the abrasion state of the ball screw pair is necessary. In the operation process, the pretightening force is an important index for monitoring, friction and wear influence the friction torque, and the friction torque is related to the pretightening force.
At present, the method for measuring the pretightening force of the ball screw pair mainly comprises a direct method and an indirect method. In the ball screw pair, the acting force between the balls and the screw is in the screw nut, and the balls roll in the roller path, so that the direct measurement of the pretightening force is difficult. The direct method for measuring the pretightening force of the ball screw pair due to the fact that: and measuring the relative displacement between the screw rod nuts, if the two screw rod nuts have displacement, the gasket between the nuts is changed, so that the initial pretightening force is changed, and the change of the pretightening force can be expressed. However, specific values cannot be solved, and only the loss of the pretightening force can be shown. The indirect method is as follows: by measuring the torque of the output shaft of the servo motor, the change of the pre-tightening force is indicated by the torque. Although the pre-tightening force can be quantitatively analyzed, the operation difficulty is large.
A measuring method is provided, and a set of devices for measuring pretightening force on line are established. The current of a servo motor of the ball screw pair is monitored by using the Hall current sensor, and the real-time pre-tightening force of the ball screw pair is monitored in real time by researching the relation among the current, the friction torque and the pre-tightening force. The method can not only quantitatively analyze the pretightening force of the ball screw pair, but also has simple and easy operation. At present, the method for measuring the driving current based on the Hall current sensor is widely applied to monitoring of a numerical control machine tool, and is high in reliability and good in sensitivity, so that the method for measuring the driving current of the ball screw pair by using the Hall current sensor is feasible. The method is used for measuring the pretightening force in the field of ball screw pairs, and has certain innovation.
Disclosure of Invention
In order to overcome the defects of the prior art, the invention relates to a test device for online measuring the pretightening force of a ball screw pair, which is used for researching the relation among current, friction torque and pretightening force in the working state of the ball screw pair, researching the wear characteristic of the ball screw pair and monitoring the wear characteristic.
The technical scheme adopted by the invention is an on-line monitoring method for the pretightening force of the ball screw pair based on current, when the ball screw pair works at a constant speed in an idle state, the effective value of the driving current of a driving motor of the ball screw pair is monitored to calculate to obtain the friction moment of the ball screw pair, which is required to be overcome by the motor to keep the constant speed movement of the ball screw pair, of the motor, and the variation trend of the pretightening force of the ball screw pair based on the current of the driving motor can be realized according to the relation between the friction moment of the ball screw pair and.
The actual working conditions of the ball screw pair in the machine equipment (such as a numerical control machine tool) are not damaged and influenced, and the evaluation and the prediction of the abrasion and the pre-tightening state of the ball screw pair can be realized only by monitoring the driving current of the driving motor when the ball screw pair rotates at a constant speed in a no-load way at a specified rotating speed at regular intervals according to the change rule of the driving current.
The test device for realizing the method comprises a bearing end seat, a marble base, a workbench, a cylindrical nut, a gasket, a positioning pin, a flange nut, a sliding block, a ball screw, a linear guide rail, a coupler, a servo motor and a Hall current sensor.
The ball screw is rigidly connected with the shaft of the servo motor through the coupler, the screw nut is rigidly connected with the ball screw pair, the linear guide rail plays a supporting role at two ends of the workbench, and meanwhile, the displacement precision of the workbench can be guaranteed. The cylindrical nut and the flange nut are reversely screwed on the lead screw nut, are in interference fit, and are extruded by the gasket to generate initial pretightening force, and the gasket is ensured not to move by using the positioning pin.
The workbench is matched with a ball screw and a flange nut to work. Under the rotation of the ball screw, the flange nut converts the rotary motion into linear motion, so that the workbench can reciprocate. The ball screw is connected with the servo motor through a coupler, so that a power source is obtained. The linear guide rail is fixed on the marble base, and the sliding block on the workbench moves linearly on the linear guide rail, so that the marble base bears the pressure on the workbench.
And the cylindrical nut and the flange nut are respectively rotated in opposite directions to apply pressure, and meanwhile, the gasket and the positioning pin are used for fixing the cylindrical nut and the flange nut. The clearance of gasket makes two nuts produce the pretightning force, and the relative position of two nuts has been guaranteed to the locating pin.
Angular contact bearings in both the bearing end seat and the coupling act on the ball screw to position the ball screw while preventing axial and radial play of the ball screw.
The Hall current sensor penetrates through one of power lines of the servo motor and is used for measuring the driving current of the servo motor.
Compared with the prior art, the invention has the beneficial effects that:
1) according to the device, the loading current of the servo motor is measured in real time through the Hall eddy current sensor, the rotating speed is obtained through fast Fourier transform of the loading current, further, the friction torque is obtained, and the pre-tightening force is obtained through the relation between the friction torque and the pre-tightening force. And because the acting force between the ball and the raceway is difficult to directly measure, the method can be used for realizing the quantitative analysis of the pretightening force of the ball screw pair. In the measuring process, easy operation need not to shut down, and the effect is high, can monitor ball wearing and tearing and need not the dismouting.
2) The method is based on the ball screw pair which runs at a constant speed in an unloaded state, and because the ball screw pair does not have extra impact and additional load in the state, compared with a conventional screw pre-tightening force prediction experiment table, the method is closer to the relation between the pre-tightening force and the friction torque, so that the calculated pre-tightening force is more real, and the method can realize the on-line prediction of the pre-tightening force of the ball screw pair.
Drawings
FIG. 1 is a front view of the present invention;
FIG. 2 is a top view of the present invention;
FIG. 3 is an operational diagram of a Hall current sensor in the testing apparatus of the present invention.
Detailed Description
The measuring method of the device for measuring the pretightening force is described as follows:
further: in order to achieve the above object, the present invention provides a device for online measurement of preload force of a ball screw assembly, the device comprising: bearing end seat, marble base, workstation, cylinder nut, gasket, locating pin, flange nut (7), slider (8), ball (9), linear guide (10), shaft coupling (11), servo motor (12), hall current sensor (13).
Further: the cylindrical nut (4) and the flange nut (7) are rotated in opposite directions respectively to apply pressure, and meanwhile, the cylindrical nut (4) and the flange nut (7) are fixed through the gasket (5) and the positioning pin (6). The double nut is pre-tensioned by using a spacer to create an initial pre-stress.
Further: by using a servo motor (12), the motion is transmitted to the ball screw (9) via a coupling (11), at which point the ball screw (9) starts to rotate. At the moment, the cylindrical nut (4) and the flange nut (7) can generate linear motion under the action of the ball screw (9), and high transmission efficiency is guaranteed.
Further: the Hall current sensor (13) penetrates through one of power lines of the servo motor (12) and is used for measuring the driving current of the servo motor (12), so that the rotating speed and the power of the servo motor (12) are calculated. Signals acquired by the Hall current sensor (13) are acquired by an acquisition card, and the pretightening force is solved through the relation between the servo motor driving current, the friction torque and the pretightening force so as to realize the monitoring of the pretightening force.
Further: the current value I measured by the Hall current sensor (13)NIs a set of arrays measured at a sampling frequency of 6400. Obtaining the frequency point f of the maximum amplitude value by fast Fourier calculation and indexing the maximum value of the arraya. At this time: speed n ═ f of servo motora60/p, p is the number of pole pairs of the motor; power of screw pair
Wherein U is the working voltage of the servo motor,
is the effective value of the current,
power factor equal to 0.85; the resultant moment T is 9550. P/n; friction torque Tpη · T, η is the conversion; pretightening force
PhIs the lead, beta is the lead angle. Therefore, a relation between the current and the pre-tightening force of the ball screw pair is obtained:
pre-tightening force:
Claims (2)
1. a current-based ball screw pair pretightening force on-line monitoring method is disclosed, wherein a test device for realizing the method comprises a bearing end seat, a marble base, a workbench, a cylindrical nut, a gasket, a positioning pin, a flange nut, a sliding block, a ball screw, a linear guide rail, a coupler, a servo motor and a Hall current sensor;
the ball screw is rigidly connected with a shaft of the servo motor through the coupler, the screw nut is rigidly connected with the ball screw pair, the linear guide rail plays a supporting role at two ends of the workbench, and the displacement precision of the workbench is ensured; the cylindrical nut and the flange nut are reversely screwed on the screw nut and are in interference fit, the two nuts are extruded by the gasket to generate initial pretightening force, and the gasket is ensured not to move by using the positioning pin;
the method is characterized in that: when the ball screw pair works at a constant speed in an idle load mode, the effective value of the driving current of the driving motor of the ball screw pair is monitored to calculate to obtain the friction torque of the ball screw pair, which is required to be overcome by the motor to keep the ball screw pair moving at the constant speed, and the variation trend of the pretightening force of the ball screw pair is monitored based on the current of the driving motor according to the relation between the friction torque of the ball screw pair and the pretightening force;
the working table is matched with the ball screw and the flange nut to work; under the rotation of the ball screw, the flange nut converts the rotary motion into linear motion, so that the workbench can reciprocate; the ball screw is connected with the servo motor through a coupler, so that a power source is obtained; the linear guide rail is fixed on the marble base, and the sliding block on the workbench moves linearly on the linear guide rail, so that the marble base bears the pressure on the workbench;
respectively rotating the cylindrical nut and the flange nut in opposite directions to apply pressure, and fixing the cylindrical nut and the flange nut by using a gasket and a positioning pin; the gap of the gasket enables the double nuts to generate pretightening force, and the positioning pin ensures the relative positions of the two nuts;
angular contact bearings in the bearing end seat and the coupling act on the ball screw to position the ball screw and prevent the ball screw from moving in the axial direction and the radial direction;
the Hall current sensor (13) penetrates through one of power lines of the servo motor (12) and is used for measuring the driving current of the servo motor (12), so that the rotating speed and the power of the servo motor (12) are calculated; signals acquired by the Hall current sensor (13) are acquired by an acquisition card, and the pretightening force is solved through the relation between the servo motor driving current, the friction torque and the pretightening force so as to realize the monitoring of the pretightening force.
2. The current-based ball screw pair pretightening force on-line monitoring method as claimed in claim 1, wherein: the current value I measured by the Hall current sensor (13)NIs a set of arrays measured at a sampling frequency of 6400; obtaining the frequency point f of the maximum amplitude value by fast Fourier calculation and indexing the maximum value of the arraya(ii) a At this time: speed n ═ f of servo motora60/p, p is the number of pole pairs of the motor; power of screw pair
Wherein U is the working voltage of the servo motor,
is the effective value of the current,
power factor equal to 0.85; the resultant moment T is 9550. P/n; friction torque Tpη · T, η is the conversion; pretightening force
PhIs the lead, beta is the lead angle; therefore, a relation between the current and the pretightening force of the ball screw pair is obtained:
pre-tightening force:
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201811490353.9A CN109556778B (en) | 2018-12-06 | 2018-12-06 | Current-based ball screw pair pretightening force on-line monitoring method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201811490353.9A CN109556778B (en) | 2018-12-06 | 2018-12-06 | Current-based ball screw pair pretightening force on-line monitoring method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN109556778A CN109556778A (en) | 2019-04-02 |
| CN109556778B true CN109556778B (en) | 2021-03-16 |
Family
ID=65869363
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201811490353.9A Active CN109556778B (en) | 2018-12-06 | 2018-12-06 | Current-based ball screw pair pretightening force on-line monitoring method |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN109556778B (en) |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110842644B (en) * | 2019-11-09 | 2021-02-02 | 北京工业大学 | Method for monitoring contact stiffness degradation rate of machine tool moving part based on numerical control load information |
| CN111735626A (en) * | 2020-07-10 | 2020-10-02 | 南京理工大学 | Comprehensive evaluation method for precision retentivity test of ball screw pair |
| CN111982380B (en) * | 2020-07-16 | 2022-04-19 | 南京理工大学 | Ball screw pair pretightening force detection method and system based on characteristic frequency |
| CN114545228B (en) * | 2022-01-26 | 2022-11-22 | 图湃(北京)医疗科技有限公司 | OCT system ball screw wear state monitoring method based on motor current feedback |
| CN114965489B (en) * | 2022-04-20 | 2023-11-14 | 江苏品德机电科技有限公司 | Conveying line with surface defect detection for ball screw pair machining |
| CN115041714A (en) * | 2022-06-19 | 2022-09-13 | 南京中科煜宸激光技术有限公司 | Rotating shaft health monitoring device and method for powder-laying type metal additive manufacturing equipment |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| SU759885A1 (en) * | 1979-01-26 | 1980-08-30 | Otdel Kompleks Proekt Bakuv | Device for static testing of building structures |
| CN103926875B (en) * | 2014-04-18 | 2016-08-31 | 东南大学 | A kind of Ball-screw Drive Systems friction compensation method |
| CN204269365U (en) * | 2014-12-08 | 2015-04-15 | 西安交通大学 | A kind of pretension adjustable rolling ball screw pair moment of friction dynamic measurement device |
| CN106404254A (en) * | 2016-11-17 | 2017-02-15 | 哈尔滨理工大学 | Working platform for measuring rolling friction force |
| CN106706346A (en) * | 2016-12-30 | 2017-05-24 | 南昌大学 | Steering-by-wire system test bench |
| CN108645616A (en) * | 2018-06-26 | 2018-10-12 | 北京工业大学 | The random abrasion test method of ball screw assembly, based on preload with feeding rotating speed |
-
2018
- 2018-12-06 CN CN201811490353.9A patent/CN109556778B/en active Active
Also Published As
| Publication number | Publication date |
|---|---|
| CN109556778A (en) | 2019-04-02 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN109556778B (en) | Current-based ball screw pair pretightening force on-line monitoring method | |
| CN103926077B (en) | A kind of ball-screw Static and dynamic stiffness comprehensive measurement device | |
| CN103900813B (en) | The measurement mechanism of a kind of ball screw turns inertia and moment of friction | |
| CN106596087B (en) | A kind of device and method of novel achievable whole assembly Friction identification | |
| CN108871634B (en) | Testing device for testing friction moment and axial load of ball screw pair on line | |
| CN110095217B (en) | Device and method for measuring friction torque of rolling bearing | |
| CN103018104A (en) | Horizontal measuring device for axial static rigidity of ball screw pair and method thereof | |
| CN111521392B (en) | Ball and rolling linear guide rail reverser friction torque detection device | |
| CN203572643U (en) | Electromechanical servo mechanism rigidity testing device | |
| CN110398359A (en) | A kind of dynamic testing method and device of mechanical drive train composition error | |
| CN203011772U (en) | Axial static stiffness horizontal measuring device of ball lead screw pair | |
| CN108645616A (en) | The random abrasion test method of ball screw assembly, based on preload with feeding rotating speed | |
| CN110887590A (en) | High-speed bearing friction tester | |
| Kim et al. | Effect of preload on running accuracy of spindle | |
| CN112393900A (en) | Ball screw pair friction testing device | |
| CN112008490A (en) | Method for detecting reverse clearance of numerical control machine tool of full closed-loop servo system | |
| CN116678617A (en) | Precision measuring device of small-lead planetary roller screw | |
| CN109406143A (en) | Ball screw assembly precision retaining ability testing device and method based on real working condition | |
| CN211978324U (en) | Linear guide rail pair prepressing damping force testing platform | |
| Zheng et al. | Research on Detect Method for Transmission Accuracy and Efficiency of Planetary Roller Screw Pair | |
| CN111189379B (en) | Inner cavity surface roughness in-situ detection method based on double-point rotational friction | |
| CN204439204U (en) | A kind of gap adjustment frock of vibration-testing | |
| CN114526663A (en) | Straightness detection tool, detection method and detection method | |
| CN208818112U (en) | A kind of instrument of the ball screw lead measurement of money hand-held | |
| CN111922783A (en) | Machine tool multidimensional geometric error measuring method based on lever principle |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |