A main shaft box servo compensation method based on change of steel wire rope load

Abstract

This invention provides a spindle box servo compensation method based on wire rope load variation. It includes installing a tension sensor on the front wire rope of a CNC floor-type milling and boring machine. The front wire rope is driven to move by a driver, establishing a spindle box balance model. This model includes the required tension value of the wire rope at any position of the slide or boring bar, a functional relationship between the required tension value of the wire rope and the voltage of the corresponding driver, and in actual operation, the real-time measurement value of the tension sensor is obtained when the slide or boring bar moves. It is then determined whether the real-time measurement value of the tension sensor is consistent with the required tension value of the wire rope at that position. If they are inconsistent, the voltage of the driver is automatically adjusted to make the real-time measurement value of the tension sensor consistent with the required tension value of the wire rope at that position, thus performing real-time compensation. This invention is simple, can achieve automatic adjustment and compensation, has a fast response, and can meet the real-time adjustment of the spindle box balance of a floor-type milling and boring machine, thereby meeting the accuracy requirements of the spindle box.

Description

Technical Field

[0001] This invention relates to the field of spindle box balance adjustment technology for CNC floor-type milling and boring machines, specifically to a spindle box servo compensation method based on changes in wire rope load. Background Technology

[0002] Currently, the layout of CNC floor-type milling and boring machines involves the boring bar, ram, or boring rod being horizontally arranged within the spindle box. The spindle box is connected to the machine via two steel wire ropes and a counterweight in a side-mounted structure. Due to the weight of the moving parts, the boring bar, ram, or boring rod inevitably disrupts the spindle box's balance when extended, affecting the machine tool's operating accuracy. Therefore, a spindle box balance compensation system has always been a crucial technology for improving the accuracy of floor-type milling and boring machines. The widely used compensation method involves adding a hydraulic cylinder between the front or rear suspension point of the steel wire rope and the spindle box, maintaining the dynamic balance of the spindle box by controlling the cylinder's stroke. However, hydraulic cylinder compensation has the following problems: the inlet pipe diameter is much smaller than the cylinder diameter, requiring a certain amount of time to adjust the oil level in the cylinder, resulting in a lag in adjustment. Furthermore, hydraulic oil is essentially a liquid, and liquids have a certain elasticity and are compressible. Therefore, when injecting oil into the hydraulic cylinder to increase pressure, more oil than theoretically required needs to be added to the cylinder to reach the set pressure; conversely, when releasing oil to reduce pressure, more oil than theoretically required needs to be released to reduce pressure to the set pressure. This will result in a longer delay in hydraulic cylinder adjustments. Summary of the Invention

[0003] To address the shortcomings of existing technologies, the purpose of this invention is to provide a spindle box servo compensation method based on wire rope load variation. This method is simple, can achieve automatic adjustment and compensation, has a fast response, and can meet the real-time adjustment of the spindle box balance of floor-type milling and boring machines, thereby meeting the accuracy requirements of the spindle box.

[0004] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0005] A spindle box servo compensation method based on wire rope load variation includes the following steps:

[0006] A tension sensor is installed on the front wire rope of a CNC floor-type milling and boring machine, wherein the front wire rope is driven to move by a driver;

[0007] Establish a spindle box balance model, including the required tension value of the wire rope at any position of the slide or boring bar, the functional relationship between the required tension value of the wire rope and the voltage of the corresponding driver;

[0008] In practical work, the real-time measurement value of the tension sensor is obtained when the slide or boring bar moves;

[0009] The system determines whether the real-time measurement value of the tension sensor matches the required tension value of the wire rope corresponding to the slide or boring bar at that position. If they do not match, the voltage of the driver is automatically adjusted to make the real-time measurement value of the tension sensor match the required tension value of the wire rope corresponding to the slide or boring bar at that position, thus performing real-time compensation.

[0010] Furthermore, the driver includes a servo motor, a gearbox, and a ball screw mechanism. The ball screw mechanism includes a screw nut and a screw. The screw is fixed to the front wire rope. The output shaft of the servo motor is connected to the gearbox, and the output shaft of the gearbox is fixed to the screw nut.

[0011] Furthermore, the CNC floor-type milling and boring machine also includes a CNC system (NCU), a drive module (SMM), and a PLC analog input module;

[0012] The PLC analog input module is used to read the real-time measurement values ​​measured by the tension sensor;

[0013] The spindle box balance model is embedded in the CNC system to calculate the position of the slide or boring bar and the corresponding required tension value of the wire rope, the required tension value of the wire rope and the voltage of the corresponding driver;

[0014] The SMM (Side Module for Servo Motors) is used to drive the servo motor.

[0015] Furthermore, the tension sensor converts the measured real-time value into a voltage signal, and the PLC analog input module converts the acquired voltage signal into a digital signal for reading through D / A conversion.

[0016] Furthermore, the position of the slide or boring bar is obtained by the CNC system (NCU) through a position sensor.

[0017] Furthermore, the travel of the ram or boring bar within the spindle box is divided into n equal regions, with a distance of ΔZ for each region and a starting position of Z for each region. n The endpoint of each region is Z. n+1 ΔZ=Z n+1 -Z n The ram or boring bar at Z n The tension in the wire rope is N. n The ram or boring bar at Z n+1 The tension in the wire rope is N. n+1 ;

[0018] The slide or boring bar at Z n and Z n+1 The change in tension ΔN of the wire rope n =N n+1 -N n ;

[0019] The slide or boring bar at any position Z p To control the dynamic balance of the spindle box, the required tension N of the wire rope is... z The expression is:

[0020] N z =N n +(Z p - Z n )*ΔN n / ΔZ = N n +(Z p - Z n )*( N n+1 -N n ) / ( Z n+1 -Z n ).

[0021] Furthermore, the tension sensor converts the tension N of the wire rope into an analog voltage signal of 0-10V, which is then transmitted to the slide or boring bar at the Z-axis. n The tension N of the wire rope n The corresponding voltage is V n The ram or boring bar at Z n+1 The tension N of the wire rope n+1 The corresponding voltage is V n+1 The ram or boring bar at Z n and Z n+1 The change in tension ΔN of the wire rope n The corresponding voltage change is ΔV n Then, the expression for the voltage Vz of the actuator corresponding to the required tension Nz of the wire rope when the ram or boring bar is at any position Zp is:

[0022] V z =V n +(Z p -Z n )*ΔV n / ΔZ=V n +(Z p -Z n )*(V n+1 -V n ) / (Z n+1 -Z n ).

[0023] Furthermore, the slide or boring bar moves linearly within the spindle box.

[0024] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0025] This invention provides a spindle box servo compensation method based on changes in wire rope load. Specifically, it's a dynamic balance servo compensation method for the spindle box based on changes in the load of the front wire rope. The method automatically monitors changes in the load tension of the front wire rope as the ram or boring bar moves within the spindle box. Then, based on a function calculation from the spindle box balance model, it obtains the position of the ram or boring bar, the corresponding required wire rope tension value, the required wire rope tension value, and the voltage of the driver. The driver then drives the front wire rope to move, adjusting its load tension so that the real-time measurement value from the tension sensor matches the required wire rope tension value at that position of the ram or boring bar. The ultimate goal is to compensate for the spindle box balance, achieving dynamic equilibrium. Attached Figure Description

[0026] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this application, illustrate exemplary embodiments of the invention and are intended to explain the invention, but do not constitute an undue limitation thereof. In the drawings:

[0027] Figure 1 This is a flowchart of the spindle box servo compensation method based on the load variation of the wire rope according to the present invention.

[0028] Figure 2 This is a schematic diagram of the servo compensation device for the spindle box of the CNC floor-type milling and boring machine of the present invention.

[0029] Figure 3 This is the electrical wiring diagram for the spindle box servo compensation method based on wire rope load variation of the present invention.

[0030] The components include: 1. Servo motor; 2. Gearbox; 3. Ball screw mechanism; 4. Tension sensor; 5. Spindle box; 6. Slide or boring bar; 7. Front wire rope; 8. Rear wire rope; 9. Numerical control system (NCU); 10. Drive module (SMM); 11. PLC analog input module. Detailed Implementation

[0031] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

[0032] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0033] In related technologies, the dynamic balance of the spindle box 5 is usually maintained by controlling the stroke of the hydraulic cylinder. However, the adjustment of the hydraulic cylinder has a time lag and cannot compensate for the spindle box 5 in real time.

[0034] This invention provides a spindle box servo compensation method based on wire rope load variation, such as... Figure 1 As shown, it includes the following steps:

[0035] A tension sensor 4 is installed on the front wire rope 7 of the CNC floor milling and boring machine, wherein the front wire rope 7 is driven to move by a driver;

[0036] Establish a balance model for the spindle box 5. The balance model for the spindle box 5 includes the functional relationship between the position of the slide or boring bar 6 and the corresponding required tension value of the wire rope, the required tension value of the wire rope and the voltage of the corresponding driver.

[0037] In practical work, the real-time measurement value of the tension sensor 4 is obtained when the slide or boring bar 6 moves;

[0038] If the real-time measurement value of the tension sensor 4 is consistent with the required tension value of the wire rope corresponding to the slide or boring bar 6 at that position, the voltage of the driver is automatically adjusted to make the real-time measurement value of the tension sensor 4 consistent with the required tension value of the wire rope corresponding to the slide or boring bar 6 at that position, and real-time compensation is performed.

[0039] This invention provides a spindle box servo compensation method based on the load change of the wire rope, specifically a dynamic balance servo compensation method for the spindle box 5 based on the load change of the front wire rope 7. The method automatically monitors the load tension change of the front wire rope 7 as the ram or boring bar 6 moves within the spindle box 5. Then, based on the function calculation of the spindle box 5 balance model, it obtains the position of the ram or boring bar 6 and the corresponding required wire rope tension value, the required wire rope tension value, and the voltage of the driver. The driver then drives the front wire rope 7 to move, adjusting the load tension of the front wire rope 7 so that the real-time measurement value of the tension sensor 4 matches the required wire rope tension value corresponding to the position of the ram or boring bar 6. The ultimate goal is to compensate for the balance of the spindle box 5, enabling it to achieve dynamic balance.

[0040] In this invention, such as Figure 2 As shown, the CNC floor-type milling and boring machine includes a driver, a tension sensor 4, a spindle box 5, a ram or boring bar 6, a front wire rope 7, and a rear wire rope 8.

[0041] The spindle box 5 is equipped with a front wire rope 7 and a rear wire rope 8. A ram or boring bar 6 is located inside the spindle box 5. When the ram or boring bar 6 extends or retracts from the spindle box 5, the entire spindle box 5 assembly tilts due to the change in the center of gravity. The movement of the ram or boring bar 6 within the spindle box 5 causes a change in the balance between the front wire rope 7 and the rear wire rope 8, resulting in a change in the tension value measured by the tension sensor 4 of the front wire rope 7. By adjusting the voltage of the driver, the driver moves the front wire rope 7, ensuring that the real-time measurement value of the tension sensor 4 matches the required tension value of the wire rope corresponding to the position of the ram or boring bar 6.

[0042] Specifically, such as Figure 2 As shown, the driver includes a servo motor 1, a gearbox 2, and a ball screw mechanism 3. The ball screw mechanism 3 includes a screw nut and a screw. The screw is fixed to the front steel wire rope 7. The output shaft of the servo motor 1 is connected to the gearbox 2. The output shaft of the gearbox 2 is fixed to the screw nut. The servo motor 1 drives the gearbox 2 to rotate, thereby reducing the speed of the gearbox 2. The output shaft of the gearbox 2 drives the screw nut to rotate, thereby driving the screw to move up and down, thus driving the front steel wire rope 7 to move.

[0043] In this invention, such as Figure 3 As shown, the embodiment of the invention provides an electrical wiring diagram for a spindle box servo compensation method based on wire rope load variation, including: a numerical control system NCU9, a drive module SMM10, a servo motor 1, a tension sensor 4, and a PLC analog input module 11.

[0044] Specifically: the PLC analog input module 11 reads the wire rope load measured by the tension sensor 4, the drive module SMM10 drives the servo motor 1 to work, and the spindle box balance model calculation function embedded in the CNC system NCU9 calculates the tension required for the wire rope 7 load to maintain the spindle box 5 balance at any position before the slide or boring bar 6 is balanced. Then, after comparing with the measured value of the tension sensor 4, the CNC system NCU9 sends a command to the servo drive module to control the servo motor 1 to run.

[0045] The load tension of the front wire rope 7 is related to the position of the slide or boring bar 6. The wire rope tension control calculation function is embedded in the CNC system to move the slide or boring bar 6 within the spindle box 5 to maintain the balance of the spindle box 5. During the operation of the slide or boring bar 6, the corresponding compensation program is automatically executed.

[0046] In this invention, the position of the slide or boring bar 6 is obtained by the CNC system through a position sensor, and the slide or boring bar 6 moves linearly within the spindle box 5.

[0047] A spindle box servo compensation method based on wire rope load variation includes the following steps:

[0048] The spindle box 5 is connected to the counterweight via the front wire rope 7 to maintain the balance of the spindle box 5. The tension N of the front wire rope 7 is...

[0049] When the slide or boring bar 6 moves, the center of gravity of the spindle box 5 will change, and the tension of the front wire rope 7 will also change. It is necessary to control the change of the tension ΔN of the front wire rope 7 to maintain the balance of the spindle box 5.

[0050] The servo motor 1 is controlled to move according to the change of tension ΔN of the front wire rope 7. The servo motor 1 controls the rise and fall of the lead screw to control the dynamic balance of the spindle box 5.

[0051] The travel of the slide or boring bar 6 within the spindle box 5 is divided into n regions on average, with the distance between each region being ΔZ.

[0052] The starting position of each region is Z. n ;

[0053] The endpoint of each region is Z. n+1 ;

[0054] ΔZ=Z n+1 -Z n ;

[0055] 6-inch slide or boring bar in Z n The tension in the front wire rope 7 is N. n ;

[0056] 6. Slide or boring bar in Z n+1 The tension in the front wire rope 7 is N. n+1 ;

[0057] 6. Slide or boring bar in Z n and Z n+1 The change in tension ΔN of the steel wire rope 7 between n =N n+1 -N n ;

[0058] The slide or boring bar 6 is in any position Z p To control the dynamic balance of the spindle box 5, the required tension in the front wire rope 7 is denoted as N. z ;

[0059] N z =N n +(Z p -Z n )*ΔN n / ΔZ=N n +(Z p -Z n )*(N n+1 -N n ) / (Z n+1 -Z n )

[0060] The sensor can convert the tension N of the front steel wire rope 7 into an analog voltage signal of 0-10V;

[0061] 6. Slide or boring bar in Z n The tension N of the front wire rope 7 n The corresponding voltage is V n ;

[0062] 6. Slide or boring bar in Z n+1 The tension N of the front wire rope 7 n+1 The corresponding voltage is V n+1 ;

[0063] 6. Slide or boring bar in Z n and Z n+1 The change in tension ΔN of the steel wire rope 7 between n The corresponding voltage change is ΔV n ;

[0064] The slide or boring bar 6 is in any position Z p The required tension for the steel wire rope 7 is denoted as N. z The corresponding voltage value is V z ;

[0065] V z =V n +(Z p -Z n )*ΔV n / ΔZ=V n +(Z p -Zn )*(V n+1 -V n ) / (Z n+1 -Z n )

[0066] The PLC analog input module converts the acquired voltage signal into a digital signal through D / A conversion;

[0067] The tension adjustment of the front wire rope 7 is controlled by the servo motor 1, which controls the lead screw, and the lead screw adjusts the tension of the front wire rope 7.

[0068] The servo motor 1 rotates forward, driving the ball screw mechanism 3 to move downward, increasing the tension of the front wire rope 7. When the tension sensor 4 detects that the value is equal to the set value, the servo motor 1 stops rotating.

[0069] Servo motor 1 reverses and drives ball screw mechanism 3 to move upward, reducing the tension of front wire rope 7. When tension sensor 4 detects that the value is equal to the set value, servo motor 1 stops rotating.

[0070] In summary, this invention provides a servo compensation method for the spindle box 5 based on the load variation of the front wire rope 7. It uses a sensor to read the tension value of the front wire rope 7 in real time, calculates the target tension of the front wire rope 7 required to maintain the balance of the spindle box 5 at any position of the slide or boring bar 6 according to a mathematical model, and adjusts the servo motor 1 to ensure that the real-time tension matches the target tension. The mathematical function of this invention is embedded into the control system to form a real-time control system for the balance compensation of the spindle box 5, including a CNC system, a servo motor 1, a PLC analog input module 11, a tension sensor 4, the front wire rope 7, and a lead screw. When the slide or boring bar 6 moves within the spindle box 5, the mathematical function embedded in the system calculates the required tension of the front wire rope 7 at any position. The servo motor 1 controls the movement of the lead screw to adjust the tension of the front wire rope 7 to match the calculated tension, thus maintaining the balance of the spindle box 5.

[0071] This invention provides a simple method for automatic balance compensation of the spindle box 5. The principle is simple and the cost is low. It utilizes sensors to measure the tension of the front wire rope 7 to automatically complete the balance compensation of the spindle box 5, greatly improving the reliability, safety, and accuracy maintenance of the machine tool. The spindle box 5 balance compensation method of this invention can improve the quality of machined parts.

[0072] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A spindle box servo compensation method based on wire rope load variation, characterized in that, Includes the following steps: A tension sensor is installed on the front wire rope of a CNC floor-type milling and boring machine, wherein the front wire rope is driven to move by a driver; Establish the spindle box balancing model, including: Divide the travel of the slide or boring bar within the spindle box into n equal regions, with the distance of each region being ΔZ and the starting position of each region being Z. n The endpoint of each region is Z. n+1 ΔZ=Z n+1 -Z n The ram or boring bar at Z n The tension in the wire rope is N. n The ram or boring bar at Z n+1 The tension in the wire rope is N. n+1 ; The slide or boring bar at Z n and Z n+1 The change in tension ΔN of the wire rope n =N n+1 -N n ; The slide or boring bar at any position Z p To control the dynamic balance of the spindle box, the required tension N of the wire rope is... z The expression is: N z =N n +(Z p - Z n )*ΔN n / ΔZ = N n +(Z p - Z n )*( N n+1 -N n ) / ( Z n+1 -Z n ); The tension sensor converts the tension N of the wire rope into an analog voltage signal of 0-10V, which is then transmitted to the ram or boring bar in the Z-axis direction. n The tension N of the wire rope n The corresponding voltage is V n The ram or boring bar at Z n+1 The tension N of the wire rope n+1 The corresponding voltage is V n+1 The ram or boring bar at Z n and Z n+1 The change in tension ΔN of the wire rope n The corresponding voltage change is ΔV n Then, the expression for the voltage Vz of the actuator corresponding to the required tension Nz of the wire rope when the ram or boring bar is at any position Zp is: In z =V n +(With p -Z n )*ΔV n / ΔZ=V n +(With p -Z n )*(V n+1 -V n ) / (Z n+1 -Z n ); In practical work, the real-time measurement value of the tension sensor is obtained when the slide or boring bar moves; The system determines whether the real-time measurement value of the tension sensor matches the required tension value of the wire rope corresponding to the slide or boring bar at that position. If they do not match, the voltage of the driver is automatically adjusted to make the real-time measurement value of the tension sensor match the required tension value of the wire rope corresponding to the slide or boring bar at that position, thus performing real-time compensation.

2. The spindle box servo compensation method based on wire rope load variation according to claim 1, characterized in that: The driver includes a servo motor, a gearbox, and a ball screw mechanism. The ball screw mechanism includes a screw nut and a screw. The screw is fixed to a front steel wire rope. The output shaft of the servo motor is connected to the gearbox, and the output shaft of the gearbox is fixed to the screw nut.

3. The spindle box servo compensation method based on wire rope load variation according to claim 2, characterized in that: The CNC floor-type milling and boring machine also includes a CNC system (NCU), a drive module (SMM), and a PLC analog input module; The PLC analog input module is used to read the real-time measurement values ​​measured by the tension sensor; The spindle box balance model is embedded in the CNC system to calculate the position of the slide or boring bar and the corresponding required tension value of the wire rope, the required tension value of the wire rope and the voltage of the corresponding driver; The SMM (Side Module for Servo Motors) is used to drive the servo motor.

4. The spindle box servo compensation method based on wire rope load variation according to claim 3, characterized in that: The tension sensor converts the real-time measured value into a voltage signal, and the PLC analog input module converts the acquired voltage signal into a digital signal for reading through D / A conversion.

5. The spindle box servo compensation method based on wire rope load variation according to claim 3, characterized in that: The position of the slide or boring bar is obtained by the CNC system (NCU) through a position sensor.

6. The spindle box servo compensation method based on wire rope load variation according to claim 1, characterized in that: The slide or boring bar moves linearly within the spindle box.

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