A method and apparatus for determining a tool spindle temperature

Abstract

This invention relates to the field of machine tool technology, and particularly to a method and apparatus for determining the temperature of a tool spindle box. The method includes: collecting real-time temperatures at the water inlet, water outlet, air inlet, and air outlet of the electric spindle of the tool spindle box, as well as the real-time temperature of the surrounding environment; determining a formula for the remaining heat of the tool spindle box based on the thermal balance relationship; determining a formula for the tool spindle box temperature based on the formula for the remaining heat of the tool spindle box; and substituting the real-time temperatures into the tool spindle box temperature formula to determine the real-time temperature value of the tool spindle box. This addresses the problems of existing tool spindle boxes having complex structures and large temperature distribution differences, resulting in large errors when measuring the internal temperature changes of the electric spindle motor at a single point; the cumbersome calculations for multi-point measurements, increasing workload and cost; and the need to modify the tool spindle box structure when using embedded temperature sensors, increasing design and maintenance difficulties.

Description

Technical Field

[0001] This invention relates to the field of machine tool technology, and in particular to a method and apparatus for determining the temperature of the tool spindle box. Background Technology

[0002] With the rapid development of high-speed cutting, more and more machine tools are using electric spindles as spindle motors. Because the electric spindle embeds a toolbox, the deformation of the toolbox caused by the heat generated during spindle movement leads to tool displacement, which has become a significant factor affecting machining accuracy. Compensating for tool displacement temperature based on toolbox temperature changes can significantly improve machining accuracy. However, due to the complex structure of the toolbox, temperature measurement is relatively difficult. Currently, the main methods for measuring toolbox temperature are single-point measurement and multi-point measurement. Single-point measurement only measures the internal temperature of the electric spindle motor. Since the toolbox has multiple heat dissipation methods with significant variations in heat dissipation power, the temperature change calculated solely from the electric spindle motor's internal temperature has a large error. Multi-point measurement uses methods such as finite element analysis to determine the installation locations of multiple temperature sensors. Due to the complex structure of the toolbox, with different shapes and materials in various parts, the temperature distribution varies greatly at different locations, increasing the workload of finite element analysis. If embedded temperature sensors are used, the impact of the installation location on the toolbox rigidity must be considered, increasing design difficulty and also increasing the difficulty of repairing temperature sensor malfunctions. Summary of the Invention

[0003] This invention proposes a method and apparatus for determining the temperature of a tool spindle box, which solves the problems of existing tool spindle boxes having complex structures and large temperature distribution differences, resulting in large errors when measuring the internal temperature changes of the electric spindle motor through a single point; the calculation is cumbersome when measuring through multiple points, increasing workload and cost; and the need to change the tool spindle box structure when measuring with embedded temperature sensors, increasing design and maintenance difficulty.

[0004] According to one aspect of the present invention, a method for determining the temperature of a tool shaft box is provided, comprising:

[0005] The first real-time temperature at the water inlet of the electric spindle of the tool shaft box, the second real-time temperature at the water outlet, the third real-time temperature at the air inlet, the fourth real-time temperature at the air outlet, and the fifth real-time temperature of the environment around the electric spindle were collected respectively.

[0006] Based on the heat balance relationship, the formula for the remaining heat of the cutter shaft box is determined, and based on the formula for the remaining heat of the cutter shaft box, the formula for the temperature of the cutter shaft box is determined.

[0007] Substitute the first, second, third, fourth, and fifth real-time temperatures into the cutter shaft box temperature formula to determine the real-time temperature value of the cutter shaft box.

[0008] Preferably, the method for determining the formula for the remaining heat of the cutter shaft box based on the heat balance relationship includes:

[0009] Formulas for obtaining the heat generated by the electric spindle motor in the cutter head box, the heat generated by the bearings in the cutter head box, the heat carried away by the circulating coolant, the heat carried away by the lubricating gas, the heat dissipation of the air on the surface of the cutter head box, and the heat dissipation of the electric spindle mounting bracket;

[0010] Based on the heat generated by the electric spindle motor in the tool shaft box, the heat generated by the bearing when the electric spindle rotates, the heat carried away by the circulating coolant, the heat carried away by the lubricating gas, the heat dissipation of the air on the surface of the tool shaft box, the heat dissipation of the electric spindle mounting bracket, and other heat loss values, combined with the heat balance relationship, the formula for the remaining heat of the tool shaft box is determined.

[0011] Preferably, the thermal balance relationship is as follows:

[0012] Q1 + Q2 - Q3 - Q4 - Q5 - Q6 - Q0 = Q7;

[0013] In the formula: Q7 is the residual heat of the cutter head box, Q1 is the heat generated by the electric spindle motor, Q2 is the heat generated by the bearing in the cutter head box, Q3 is the heat carried away by the circulating coolant, Q4 is the heat carried away by the lubricating gas, Q5 is the heat dissipation of the air on the surface of the cutter head box, Q6 is the heat dissipation of the electric spindle mounting bracket, and Q0 is other heat loss.

[0014] Preferably, the method for determining the cutter shaft box temperature formula based on the residual heat formula of the cutter shaft box includes:

[0015] The formula for the residual heat of the cutter shaft box includes a first residual heat formula and a second residual heat formula;

[0016] The formula for the first residual heat is: Formula (1);

[0017] Q7=C3m3(T-T5) (1);

[0018] In the formula: C3 is the average specific heat capacity of the cutter shaft box body, m3 is the total mass of the cutter shaft box, T is the temperature of the cutter shaft box, and T5 is the fifth real-time temperature;

[0019] The formula for the remaining heat of the cutter shaft box determined based on the heat balance relationship is the second formula for the remaining heat.

[0020] The cutter shaft box temperature formula is determined based on the first residual heat formula and the second residual heat formula.

[0021] Preferably, the second residual heat formula includes:

[0022]

[0023] Where: I is the electric spindle motor current, R is the resistance, t is the operating time of the electric spindle, and K i M is the heat generation coefficient of bearing i inside the cutter head box. i denoted as , where is the frictional torque of bearing i in the tool shaft box, j is the total number of bearings, n is the spindle speed, C1 is the specific heat capacity of the coolant, ρ1 is the density of the coolant, V1 is the flow rate of the coolant per unit time, T1 is the first real-time temperature, T2 is the second real-time temperature, Y is the heat absorption rate of the lubricating gas, m is the mass of lubricating gas passing through the air inlet per unit time, T3 is the third real-time temperature, T4 is the fourth real-time temperature, X is the ambient natural convection heat transfer coefficient, S is the surface area of ​​the tool shaft box that can dissipate heat to the air, T is the temperature of the tool shaft box, T5 is the fifth real-time temperature, λ is the thermal conductivity, A is the surface area of ​​the tool shaft box mounting bracket, T0 is the temperature of the machine tool bed, b is the thickness of the mounting bracket, and Q0 is other heat loss.

[0024] Preferably, the formula for the cutter head box temperature includes:

[0025]

[0026] Where: b is the thickness of the mounting bracket, I is the current of the electric spindle motor, R is the resistance, t is the running time of the electric spindle, and K i M is the heat generation coefficient of bearing i inside the cutter head box. i Let be the frictional torque of bearing i in the tool shaft box, j be the total number of bearings, n be the spindle speed, C1 be the specific heat capacity of the coolant, ρ1 be the density of the coolant, V1 be the flow rate of the coolant per unit time, T1 be the first real-time temperature, T2 be the second real-time temperature, Y be the heat absorption rate of the lubricating gas, m be the mass of lubricating gas passing through the air inlet per unit time, T3 be the third real-time temperature, T4 be the fourth real-time temperature, X be the ambient natural convection heat transfer coefficient, S be the surface area of ​​the tool shaft box that can dissipate heat to the air, T5 be the fifth real-time temperature, λ be the thermal conductivity, A be the surface area of ​​the tool shaft box mounting bracket, T0 be the temperature of the machine tool bed, C3 be the average specific heat capacity of the tool shaft box body, and m3 be the total mass of the tool shaft box.

[0027] Preferably, the deformation amount of the tool shaft box is determined according to the real-time temperature of the tool shaft box, and the tool displacement temperature compensation is performed according to the deformation amount.

[0028] According to one aspect of the present invention, a tool shaft box temperature determination device is provided, comprising: a host computer, a data collector, and a temperature acquisition unit;

[0029] The host computer is connected to the data collector, and the data collector is connected to the temperature acquisition unit;

[0030] The temperature acquisition unit is used to acquire the first real-time temperature at the water inlet of the electric spindle of the cutter shaft box, the second real-time temperature at the water outlet, the third real-time temperature at the air inlet, the fourth real-time temperature at the air outlet, and the fifth real-time temperature of the environment around the electric spindle.

[0031] The data collector is used to collect the temperature values ​​acquired by the temperature acquisition unit and transmit them to the host computer system;

[0032] The host computer is used to determine the formula for the remaining heat of the cutter shaft box based on the thermal balance relationship, to determine the formula for the temperature of the cutter shaft box based on the formula for the remaining heat of the cutter shaft box, and to substitute the first real-time temperature, the second real-time temperature, the third real-time temperature, the fourth real-time temperature and the fifth real-time temperature into the formula for the temperature of the cutter shaft box to determine the real-time temperature value of the cutter shaft box.

[0033] Preferably, the temperature acquisition unit includes: a first temperature sensor, a second temperature sensor, a third temperature sensor, a fourth temperature sensor, and a fifth temperature sensor;

[0034] The first temperature sensor is installed at the water inlet of the electric spindle for connecting to the water chiller, and the first temperature sensor is used to collect the first real-time temperature;

[0035] The second temperature sensor is installed at the outlet of the electric spindle for connecting to the water chiller, and the second temperature sensor is used to collect the second real-time temperature;

[0036] The third temperature sensor is installed at the air inlet of the electric spindle for connecting to the oil-air lubrication device, and the third temperature sensor is used to collect the third real-time temperature.

[0037] The fourth temperature sensor is installed at the air outlet of the electric spindle, and the fourth temperature sensor is used to collect the fourth real-time temperature.

[0038] The fifth temperature sensor is installed at a predetermined distance outside the electric spindle, and the fifth temperature sensor is used to collect the fifth real-time temperature.

[0039] The present invention has at least the following beneficial effects:

[0040] This invention proposes a method and device for determining the temperature of a cutter shaft box. By collecting the air inlet and outlet, water inlet and outlet, and ambient temperature of the cutter shaft box, and substituting them into a cutter shaft box temperature formula determined based on the thermal balance relationship, the accurate real-time temperature of the cutter shaft box can be calculated. The temperature collection location is fixed and there is no need to open holes in the cutter shaft box body, which reduces the design difficulty and makes it more versatile. Attached Figure Description

[0041] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present invention and, together with the specification, serve to explain the technical solutions of the present invention.

[0042] Figure 1 A flowchart illustrating a method for determining the temperature of the cutter headbox according to an embodiment of the present invention is shown;

[0043] Figure 2 A schematic diagram of the structure of the tool shaft box temperature determination device according to an embodiment of the present invention is shown;

[0044] Figure 3 A schematic diagram of a lubricating gas heat absorption rate measuring device according to an embodiment of the present invention is shown.

[0045] In the diagram, 1-first temperature sensor, 2-second temperature sensor, 3-third temperature sensor, 4-fourth temperature sensor, 5-fifth temperature sensor, 6-water inlet pipe, 7-water chiller, 8-water outlet pipe, 9-oil and gas lubrication device, 10-air inlet pipe, 11-data collector, 12-host computer system, 13-cable, 14-driver, 15-first data line, 16-second data line, 17-electric spindle, 18-tool spindle box, 19-pressure sensor, 20-sixth temperature sensor, 21-heating device, 22-seventh temperature sensor, 23-air chamber, 24-insulated piston, 25-counterweight, 26-insulated sealing plug, 27-air injection port, 28-insulated outer shell, 29-temperature collector with temperature display, 30-pressure collector with pressure display. Detailed Implementation

[0046] Various exemplary embodiments, features, and aspects of the present invention will now be described in detail with reference to the accompanying drawings. The same reference numerals in the drawings denote elements that have the same or similar functions. Although various aspects of the embodiments are shown in the drawings, they are not necessarily drawn to scale unless specifically indicated otherwise.

[0047] The term “exemplary” as used herein means “serving as an example, embodiment, or illustration.” Any embodiment illustrated herein as “exemplary” is not necessarily to be construed as superior to or better than other embodiments.

[0048] In this document, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent three cases: A alone, A and B simultaneously, and B alone. Furthermore, the term "at least one" in this document means any combination of at least two of any one or more elements. For example, including at least one of A, B, and C can mean including any one or more elements selected from the set consisting of A, B, and C.

[0049] Furthermore, to better illustrate the present invention, numerous specific details are set forth in the following detailed embodiments. Those skilled in the art will understand that the present invention can be practiced without certain specific details. In some instances, methods, means, elements, and circuits well known to those skilled in the art have not been described in detail in order to highlight the spirit of the invention.

[0050] Figure 1 A flowchart illustrating a method for determining the temperature of the cutter headbox according to an embodiment of the present invention is shown; Figure 2 A schematic diagram of the structure of the tool shaft box temperature determination device according to an embodiment of the present invention is shown; Figure 3 A schematic diagram of a lubricating gas heat absorption rate measuring device according to an embodiment of the present invention is shown. Figure 1-3 As shown, a method for determining the temperature of a tool spindle box includes: Step S01: Collecting the first real-time temperature at the water inlet, the second real-time temperature at the water outlet, the third real-time temperature at the air inlet, the fourth real-time temperature at the air outlet, and the fifth real-time temperature of the environment surrounding the electric spindle; Step S02: Determining the formula for the remaining heat of the tool spindle box based on the heat balance relationship, and determining the formula for the temperature of the tool spindle box based on the formula for the remaining heat of the tool spindle box; Step S03: Substituting the first, second, third, fourth, and fifth real-time temperatures into the formula for the temperature of the tool spindle box to determine the real-time temperature value of the tool spindle box.

[0051] The method for determining the temperature of the cutter headbox provided in this embodiment of the invention specifically includes the following steps:

[0052] Step S01: Collect the first real-time temperature at the water inlet of the electric spindle of the tool shaft box, the second real-time temperature at the water outlet, the third real-time temperature at the air inlet, the fourth real-time temperature at the air outlet, and the fifth real-time temperature of the environment around the electric spindle.

[0053] In this embodiment of the invention, the water inlet of the electric spindle motor in the cutter head box is connected to the outlet of the water chiller via an inlet pipe, and the water outlet of the electric spindle motor is connected to the inlet of the water chiller via an outlet pipe; the air inlet of the electric spindle motor in the cutter head box is connected to the outlet of the oil-air lubrication device via an air inlet pipe. The water chiller and the oil-air lubrication device are used to cool the electric spindle motor during operation.

[0054] The first real-time temperature is the real-time coolant temperature at the connection between the spindle inlet and the inlet pipe; the second real-time temperature is the real-time coolant temperature at the connection between the spindle outlet and the outlet pipe; the third real-time temperature is the air intake temperature at the connection between the spindle air inlet and the air intake pipe; the fourth real-time temperature is the air outlet temperature at the spindle air outlet; and the fifth real-time temperature is the ambient temperature near the spindle.

[0055] Step S02: Determine the formula for the remaining heat of the cutter shaft box based on the heat balance relationship, and determine the formula for the temperature of the cutter shaft box based on the formula for the remaining heat of the cutter shaft box.

[0056] In this invention, the method for determining the formula for the remaining heat of the tool spindle box based on the thermal balance relationship includes: obtaining the formulas for the heat generated by the electric spindle motor of the tool spindle box, the heat generated by the bearings inside the tool spindle box, the heat carried away by the circulating coolant, the heat carried away by the lubricating gas, the heat dissipation of the air on the surface of the tool spindle box, and the heat dissipation of the electric spindle mounting bracket; and determining the formula for the remaining heat of the tool spindle box based on the formulas for the heat generated by the electric spindle motor of the tool spindle box, the heat generated by the bearings when the electric spindle rotates, the heat carried away by the circulating coolant, the heat carried away by the lubricating gas, the heat dissipation of the air on the surface of the tool spindle box, the heat dissipation of the electric spindle mounting bracket, and other heat loss values, combined with the thermal balance relationship.

[0057] In this embodiment of the invention, the formula for calculating the heat generated by the electric spindle motor during operation is as shown in equation (1):

[0058] Q1 = I 2 Rt (1);

[0059] In equation (1): I is the current of the electric spindle motor, R is the resistance, and t is the running time of the electric spindle;

[0060] In this embodiment of the invention, the formula for calculating the heat generated by the internal bearings when the electric spindle rotates, i.e. the formula for the heat generated by the bearings in the tool shaft box, is shown in equation (2):

[0061]

[0062] In equation (2): K i M is the heat generation coefficient of bearing i inside the cutter head box. i denoted as the frictional torque of bearing i in the tool shaft box, j as the total number of bearings, n as the spindle speed, and t as the operating time of the electric spindle.

[0063] The frictional torque M of the needle roller bearing is obtained according to equation (21):

[0064]

[0065] In equation (21): To reduce the heat generation coefficient, G is the reduction factor for lean oil backfilling. rr This is a rolling friction variable determined by the bearing type, where v is the kinematic viscosity of the lubricant, n is the bearing speed, and G... sl The sliding friction variable, μ, is determined by the bearing type. sl K is the coefficient of sliding friction.sl d is a constant determined according to the bearing type. s Where β is the diameter of the contact surface between the seal and the bearing ring, and K is an index determined according to the type of bearing and seal. s2 V is a constant determined according to the type of bearing and seal. M The drag loss variables are the oil level height H and the average bearing diameter d. m A function of the ratio, K ball is the ball bearing constant, and B is the width of the bearing inner ring.

[0066] In this embodiment of the invention, when the water chiller is running, the coolant inside it enters the electric spindle through the inlet pipe and then flows back to the water chiller through the outlet pipe. During this process, the formula for calculating the heat carried away by the electric spindle motor by the circulating coolant is as shown in equation (3):

[0067] Q3=C1ρ1V1(T2-T1)t (3);

[0068] In equation (3): C1 is the specific heat capacity of the coolant, ρ1 is the density of the coolant, V1 is the flow rate of the coolant per unit time, T1 is the first real-time temperature, T2 is the second real-time temperature, and t is the running time of the electric spindle.

[0069] In this embodiment of the invention, during the operation of the oil-air lubrication device, the lubricating air inside enters the electric spindle through the air inlet pipe and is discharged through the air outlet. During this process, the lubricating air carries away the heat from the electric spindle motor. Since the heat absorption rate of lubricating gas varies with different oil-air ratios, accurately calculating the heat absorbed by the lubricating gas is particularly difficult. Therefore, a lubricating gas heat absorption rate measuring device is used, and based on the law of conservation of energy, the heat absorption rate of lubricating gas with different oil-air ratios can be calculated.

[0070] like Figure 3 As shown, the heat insulation shell 28 of the lubricating gas heat absorption rate measuring device is sealed at one end and has an air injection port 27 at the other end. The heat insulation shell 28 is placed vertically and suspended in the air, with the end with the air injection port 27 facing upwards. There is a heat insulation piston 24 inside the heat insulation shell 28, and a counterweight 25 under the heat insulation piston 24. The air chamber 23 is equipped with a pressure sensor 19, a sixth temperature sensor 20, a seventh temperature sensor 22, and a heating device 21. The sixth temperature sensor 20 is installed close to the heating device 21, and the seventh temperature sensor 22 is installed away from the heating device 21. The connections of the pressure sensor 19, the sixth temperature sensor 20, the seventh temperature sensor 22, and the heating device 21 are all outside the air chamber 23, and the outlets are heat-insulated and sealed. The pressure sensor 19 is connected to a pressure acquisition device 30 with a pressure display, and the sixth temperature sensor 20 and the seventh temperature sensor 22 are connected to a temperature acquisition device 29 with a temperature display. After the heat insulation sealing plug 26 is plugged, the air chamber 23 is in a heat-insulated and sealed state.

[0071] Under ambient temperature T5, the following experimental steps 1 to 3 were performed using a lubricating gas heat absorption rate measuring device:

[0072] Step 1: Remove the heat insulation sealing plug 26 and adjust the weight of the counterweight 25 to bring the heat insulation piston 24 into a state of gravity balance.

[0073] Step 2: Clean the gas chamber 23, lock the heat-insulating piston 24, evacuate the gas chamber 23 to a vacuum, and then inject lubricating gas with mass m0 and temperature T3 through the injection port 27; when the pressure sensor 19 measures a pressure p equal to 1.01325*10^5pa±1%, stop the injection, plug the heat-insulating sealing plug 26, and unlock the heat-insulating piston 24; set the heating temperature of the heating device 21 to T6, with T6 set between 50 and 80℃, and the current of the heating device 21 at heating temperature T6 to i0; after heating begins, as the temperature inside the gas chamber 23 rises, the gas pressure increases, and the heat-insulating piston 24 descends, stopping heating after time t2; when the pressure sensor 19 measures that the pressure stops changing, the pressure difference between the inside and outside gas is less than ±5%, and the temperature T7 measured by the sixth temperature sensor 20 is the same as the temperature T8 measured by the seventh temperature sensor 22, the gas inside the gas chamber 23 reaches temperature equilibrium, and the temperature T7 is obtained. T7 should be significantly less than T6, and the measurement ends.

[0074] Step 3: Repeat step 2 several times to obtain one set of T7. Exclude results with obvious deviations and take the average of the remaining T7 to obtain T9.

[0075] According to the law of conservation of energy:

[0076]

[0077] In formula (41): Y is the heat absorption rate of the lubricating gas, i0 is the current of the heating device 21, R0 is the heating resistance of the heating device, and m0 is the mass of the injected lubricating gas.

[0078] From equation (41), we get:

[0079]

[0080] In formula (42): Y is the heat absorption rate of the lubricating gas, i0 is the current of the heating device 21, R0 is the heating resistance of the heating device, m0 is the mass of the injected lubricating gas, T9 is the average value of multiple effective T7, and T6 is the heating temperature of the heating device 21.

[0081] When lubricating gas lubricates the bearing, there is an optimal value for the proportion of oil mist and the amount of gas passing through per unit time, which can be adjusted by the oil-gas lubrication device. The mass of lubricating gas passing through the inlet per unit time is a constant value. Therefore, the formula for calculating the heat Q4 carried away by the lubricating gas is as shown in equation (4):

[0082] Q4=Ym(T4-T3)t (4)

[0083] In equation (4): Y is the heat absorption rate of the lubricating gas, m is the mass of lubricating gas passing through the inlet per unit time, T3 is the third real-time temperature, and T4 is the fourth real-time temperature.

[0084] In this embodiment of the invention, the formula for the amount of heat dissipation from the air on the surface of the cutter shaft box is as shown in equation (5):

[0085] Q5=XS(T-T5)t (5);

[0086] In formula (5): X is the ambient natural convection heat transfer coefficient, S is the surface area of ​​the cutter head box that can dissipate heat to the air, T is the temperature of the cutter head box, T5 is the fifth real-time temperature, and t is the running time of the electric spindle.

[0087] In this embodiment of the invention, the heat dissipation formula for the electric spindle mounting bracket is as shown in equation (6):

[0088]

[0089] In equation (6): λ is the thermal conductivity, A is the surface area of ​​the tool spindle box mounting bracket, T is the tool spindle box temperature, T0 is the machine tool bed temperature, b is the thickness of the mounting bracket, and t is the operating time of the electric spindle. The value of T0 can be the fifth real-time temperature.

[0090] In this invention, the thermal balance relationship is as follows:

[0091] Q1+Q2-Q3-Q4-Q5-Q6-Q0=Q7 (7);

[0092] In formula (7): Q7 is the residual heat of the cutter head box, Q1 is the heat generated by the electric spindle motor, Q2 is the heat generated by the bearing in the cutter head box, Q3 is the heat carried away by the circulating coolant, Q4 is the heat carried away by the lubricating gas, Q5 is the heat dissipation of the air on the surface of the cutter head box, Q6 is the heat dissipation of the electric spindle mounting bracket, and Q0 is other heat loss.

[0093] In this embodiment of the invention, Q7 is set as the remaining heat of the cutter shaft box, and the other heat loss is Q0. Equation (7) is obtained from the heat balance relationship.

[0094] In this invention, the method for determining the temperature formula of the cutter shaft box according to the remaining heat formula of the cutter shaft box includes: the remaining heat formula of the cutter shaft box includes a first remaining heat formula and a second remaining heat formula; wherein, the first remaining heat formula is: formula (9);

[0095] Q7=C3m3(T-T5) (9);

[0096] In formula (9): C3 is the average specific heat capacity of the cutter shaft box body, m3 is the total mass of the cutter shaft box, T is the temperature of the cutter shaft box, and T5 is the fifth real-time temperature;

[0097] The formula for the remaining heat of the cutter shaft box determined based on the thermal balance relationship is the second remaining heat formula; the formula for the temperature of the cutter shaft box is determined based on the first remaining heat formula and the second remaining heat formula.

[0098] In this invention, the second residual heat formula includes:

[0099]

[0100] In equation (8): I is the electric spindle motor current, R is the resistance, t is the operating time of the electric spindle, and K i M is the heat generation coefficient of bearing i inside the cutter head box. i denoted as , where is the frictional torque of bearing i in the tool shaft box, j is the total number of bearings, n is the spindle speed, C1 is the specific heat capacity of the coolant, ρ1 is the density of the coolant, V1 is the flow rate of the coolant per unit time, T1 is the first real-time temperature, T2 is the second real-time temperature, Y is the heat absorption rate of the lubricating gas, m is the mass of lubricating gas passing through the air inlet per unit time, T3 is the third real-time temperature, T4 is the fourth real-time temperature, X is the ambient natural convection heat transfer coefficient, S is the surface area of ​​the tool shaft box that can dissipate heat to the air, T is the temperature of the tool shaft box, T5 is the fifth real-time temperature, λ is the thermal conductivity, A is the surface area of ​​the tool shaft box mounting bracket, T0 is the temperature of the machine tool bed, b is the thickness of the mounting bracket, and Q0 is other heat loss.

[0101] In this embodiment of the invention, based on the heat balance relationship, i.e., equation (7), the second residual heat calculation formula, i.e., equation (8), can be obtained by combining equations (1) to (6).

[0102] In equation (8), the value of Q0 is relatively small and can be ignored. Therefore, equation (10) can be approximated by solving it.

[0103]

[0104] Combining the second residual heat formula, i.e., equation (10), with the first residual heat formula, i.e., equation (9), we obtain the final calculation formula for the cutter shaft box temperature T, i.e., equation (11):

[0105] In this invention, the formula for the temperature of the cutter head box includes:

[0106]

[0107] In equation (11): b is the thickness of the mounting bracket, I is the current of the electric spindle motor, R is the resistance, t is the running time of the electric spindle, and K i M is the heat generation coefficient of bearing i inside the cutter head box. i Let be the frictional torque of bearing i in the tool shaft box, j be the total number of bearings, n be the spindle speed, C1 be the specific heat capacity of the coolant, ρ1 be the density of the coolant, V1 be the flow rate of the coolant per unit time, T1 be the first real-time temperature, T2 be the second real-time temperature, Y be the heat absorption rate of the lubricating gas, m be the mass of lubricating gas passing through the air inlet per unit time, T3 be the third real-time temperature, T4 be the fourth real-time temperature, X be the ambient natural convection heat transfer coefficient, S be the surface area of ​​the tool shaft box that can dissipate heat to the air, T5 be the fifth real-time temperature, λ be the thermal conductivity, A be the surface area of ​​the tool shaft box mounting bracket, T0 be the temperature of the machine tool bed, C3 be the average specific heat capacity of the tool shaft box body, and m3 be the total mass of the tool shaft box.

[0108] Step S03: Substitute the first real-time temperature, the second real-time temperature, the third real-time temperature, the fourth real-time temperature, and the fifth real-time temperature into the tool shaft box temperature formula to determine the real-time temperature value of the tool shaft box.

[0109] In this embodiment of the invention, the temperature value of the cutter headbox changing with time at a fixed rotation speed can be calculated simply and quickly according to formula (11), which is more accurate than simply collecting the temperature of the electric spindle motor and also reduces the difficulty of data analysis. During the calculation process, only the temperature data of 5 positions of the electric spindle of the cutter headbox are collected, namely the first to fifth real-time temperatures. It is not necessary to determine the temperature collection position through finite element analysis, which reduces the design difficulty.

[0110] In this invention, the deformation amount of the tool shaft box is determined according to the real-time temperature of the tool shaft box, and the tool displacement temperature compensation is performed according to the deformation amount.

[0111] In this embodiment of the invention, based on the calculated real-time temperature of the tool spindle box, the deformation of the tool spindle box caused by the heat generated by the electric spindle movement can be determined, and then the displacement of the tool caused by the deformation of the tool spindle box can be determined. Based on this displacement, displacement temperature compensation is performed on the tool, thereby greatly improving the machining accuracy of the machine tool.

[0112] It is understood that the various method embodiments mentioned above in this invention can be combined with each other to form combined embodiments without violating the principle and logic. Due to space limitations, this invention will not elaborate further.

[0113] The execution entity of the toolbox temperature determination method can be a toolbox temperature determination device. For example, the toolbox temperature determination method can be executed by a terminal device, a server, or other processing device. The terminal device can be user equipment (UE), a mobile device, a user terminal, a terminal, a cellular phone, a cordless phone, a personal digital assistant (PDA), a handheld device, a computing device, an in-vehicle device, a wearable device, etc. In some possible implementations, the toolbox temperature determination method can be implemented by a processor calling computer-readable instructions stored in memory.

[0114] Those skilled in the art will understand that, in the above-described method of the specific implementation, the order in which each step is written does not imply a strict execution order and does not constitute any limitation on the implementation process. The specific execution order of each step should be determined by its function and possible internal logic.

[0115] This invention also provides a tool spindle box temperature determination device, comprising: a host computer, a data collector, and a temperature acquisition unit; the host computer is connected to the data collector, and the data collector is connected to the temperature acquisition unit; the temperature acquisition unit is used to collect the first real-time temperature at the water inlet of the tool spindle box electric spindle, the second real-time temperature at the water outlet, the third real-time temperature at the air inlet, the fourth real-time temperature at the air outlet, and the fifth real-time temperature of the environment surrounding the electric spindle; the data collector is used to collect the temperature values ​​collected by the temperature acquisition unit and transmit them to the host computer system; the host computer is used to determine the remaining heat formula of the tool spindle box according to the heat balance relationship, determine the tool spindle box temperature formula according to the remaining heat formula of the tool spindle box, and substitute the first real-time temperature, the second real-time temperature, the third real-time temperature, the fourth real-time temperature, and the fifth real-time temperature into the tool spindle box temperature formula to determine the real-time temperature value of the tool spindle box.

[0116] In this invention, the temperature acquisition unit includes: a first temperature sensor, a second temperature sensor, a third temperature sensor, a fourth temperature sensor, and a fifth temperature sensor; the first temperature sensor is installed at the water inlet of the electric spindle for connecting to the water chiller, and is used to acquire the first real-time temperature; the second temperature sensor is installed at the water outlet of the electric spindle for connecting to the water chiller, and is used to acquire the second real-time temperature; the third temperature sensor is installed at the air inlet of the electric spindle for connecting to the oil-air lubrication device, and is used to acquire the third real-time temperature; the fourth temperature sensor is installed at the air outlet of the electric spindle, and is used to acquire the fourth real-time temperature; the fifth temperature sensor is installed at a predetermined distance outside the electric spindle, and is used to acquire the fifth real-time temperature.

[0117] In this embodiment of the invention, the electric spindle 17 is embedded in the cutter head housing 18. The water inlet of the electric spindle 17 is connected to the water chiller 7 through the water inlet pipe 6, and the water outlet of the electric spindle 17 is connected to the water chiller 7 through the water outlet pipe 8. The first temperature sensor 1 is installed at the coolant inlet of the electric spindle 17 to collect the coolant inlet water temperature, and the second temperature sensor 2 is installed at the coolant outlet of the electric spindle 17 to collect the coolant outlet water temperature.

[0118] The air inlet of the electric spindle 17 is connected to the oil-air lubrication device 9 through the air inlet pipe 10. The third temperature sensor 3 is installed at the air inlet of the electric spindle 17 to collect the air inlet temperature of the electric spindle 17. The fourth temperature sensor 4 is installed at the air outlet of the electric spindle 17 to collect the air outlet temperature of the electric spindle 17. The fifth temperature sensor 5 is placed next to the electric spindle 17 to collect the ambient temperature.

[0119] The first temperature sensor 1, the second temperature sensor 2, the third temperature sensor 3, the fourth temperature sensor 4, and the fifth temperature sensor 5 are connected to the data collector 11, and the data collector 11 is connected to the host computer system 12 via the first data cable 15.

[0120] The electric spindle 17 is connected to the driver 14 via cable 13, and the driver 14 is connected to the host computer system 12 via a second data line 16.

[0121] During operation, the host computer system 12, driver 14, water chiller 7 and oil-air lubrication device 9 are started. The host computer system 12 controls the electric spindle to reach the predetermined speed through the driver 14. The data collector 11 collects the real-time temperature data detected by the first temperature sensor 1, the second temperature sensor 2, the third temperature sensor 3, the fourth temperature sensor 4 and the fifth temperature sensor 5. The data collector 11 transmits the real-time temperature data to the host computer system 12. The driver 14 transmits the current data to the host computer system 12. The host computer system 12 calculates the average temperature of the electric spindle according to formula (11). This temperature is used by the host computer system 12 as temperature compensation data to determine the displacement amount that the tool needs to be adjusted.

[0122] In some embodiments, the apparatus provided by the present invention may have functions or include devices that can be used to perform the methods described in the above method embodiments. The specific implementation of these methods can be referred to the description of the above method embodiments, and for the sake of brevity, they will not be repeated here.

[0123] The method and apparatus for determining the temperature of the cutter head box of the present invention are based on energy balance. By calculating the heat generated by the electric spindle motor, the heat generated by bearing friction, and the heat dissipated by various forms of forced and natural cooling, the temperature change of the cutter head box is finally calculated. This method comprehensively considers several temperature-influencing factors, including the interaction between the circulating coolant and the inner wall of the coolant jacket, the interaction between the stationary outer shell and ambient air, the forced convection between the bearing balls and compressed air, and the heat radiation heat transfer from the electric spindle to the surrounding environment. This makes the calculation results more consistent with the actual temperature of the cutter head box. Furthermore, the temperature acquisition location is fixed and does not require openings in the cutter head box body, reducing design complexity and increasing versatility. The temperature acquisition location facilitates installation and maintenance and does not affect the rigidity of the cutter head box body.

[0124] The various embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical application, or technical improvements to the embodiments in the market, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. A method for determining the temperature of a tool shaft box, characterized in that, include: The first real-time temperature at the water inlet of the electric spindle of the tool shaft box, the second real-time temperature at the water outlet, the third real-time temperature at the air inlet, the fourth real-time temperature at the air outlet, and the fifth real-time temperature of the environment around the electric spindle were collected respectively. Based on the heat balance relationship, the formula for the remaining heat of the cutter shaft box is determined, and based on the formula for the remaining heat of the cutter shaft box, the formula for the temperature of the cutter shaft box is determined. The formula for the temperature T of the cutter shaft box includes: ； Where: b is the thickness of the mounting bracket, I is the current of the electric spindle motor, R is the resistance, t is the running time of the electric spindle, and K i M is the heat generation coefficient of bearing i inside the cutter head box. i Let be the frictional torque of bearing i in the tool shaft box, j be the total number of bearings, n be the spindle speed, C1 be the specific heat capacity of the coolant, ρ1 be the density of the coolant, V1 be the flow rate of the coolant per unit time, T1 be the first real-time temperature, T2 be the second real-time temperature, Y be the heat absorption rate of the lubricating gas, m be the mass of lubricating gas passing through the air inlet per unit time, T3 be the third real-time temperature, T4 be the fourth real-time temperature, X be the ambient natural convection heat transfer coefficient, S be the surface area of ​​the tool shaft box that can dissipate heat to the air, T5 be the fifth real-time temperature, λ be the thermal conductivity, A be the surface area of ​​the tool shaft box mounting bracket, T0 be the temperature of the machine tool bed, C3 be the average specific heat capacity of the tool shaft box body, and m3 be the total mass of the tool shaft box. Substitute the first, second, third, fourth, and fifth real-time temperatures into the cutter shaft box temperature formula to determine the real-time temperature value of the cutter shaft box.

2. The method for determining the temperature of the cutter head box according to claim 1, characterized in that, The method for determining the formula for the remaining heat of the cutter shaft box based on the thermal balance relationship includes: Formulas for obtaining the heat generated by the electric spindle motor in the cutter head box, the heat generated by the bearings in the cutter head box, the heat carried away by the circulating coolant, the heat carried away by the lubricating gas, the heat dissipation of the air on the surface of the cutter head box, and the heat dissipation of the electric spindle mounting bracket; Based on the heat generated by the electric spindle motor in the tool shaft box, the heat generated by the bearing when the electric spindle rotates, the heat carried away by the circulating coolant, the heat carried away by the lubricating gas, the heat dissipation of the air on the surface of the tool shaft box, the heat dissipation of the electric spindle mounting bracket, and other heat loss values, combined with the heat balance relationship, the formula for the remaining heat of the tool shaft box is determined.

3. The method for determining the temperature of the cutter head box according to claim 2, characterized in that, The thermal balance relationship is as follows: ； In the formula: Q7 is the residual heat of the cutter head box, Q1 is the heat generated by the electric spindle motor, Q2 is the heat generated by the bearing in the cutter head box, Q3 is the heat carried away by the circulating coolant, Q4 is the heat carried away by the lubricating gas, Q5 is the heat dissipation of the air on the surface of the cutter head box, Q6 is the heat dissipation of the electric spindle mounting bracket, and Q0 is other heat loss.

4. The method for determining the temperature of the cutter head box according to any one of claims 1-3, characterized in that, The method for determining the temperature formula of the cutter shaft box based on the formula for the remaining heat of the cutter shaft box includes: The formula for the residual heat of the cutter shaft box includes a first residual heat formula and a second residual heat formula; The formula for the first residual heat is: Formula (1); （1）； In the formula: C3 is the average specific heat capacity of the cutter shaft box body, m3 is the total mass of the cutter shaft box, T is the temperature of the cutter shaft box, and T5 is the fifth real-time temperature; The formula for the remaining heat of the cutter shaft box determined based on the heat balance relationship is the second formula for the remaining heat. The cutter shaft box temperature formula is determined based on the first residual heat formula and the second residual heat formula.

5. The method for determining the temperature of the cutter head box according to claim 4, characterized in that, The second residual heat formula includes: ； Where: I is the electric spindle motor current, R is the resistance, t is the operating time of the electric spindle, and K i M is the heat generation coefficient of bearing i inside the cutter head box. i denoted as , where i is the frictional torque of bearing i in the tool shaft box, j is the total number of bearings, n is the spindle speed, C1 is the specific heat capacity of the coolant, ρ1 is the density of the coolant, V1 is the flow rate of the coolant per unit time, T1 is the first real-time temperature, T2 is the second real-time temperature, Y is the heat absorption rate of the lubricating gas, m is the mass of lubricating gas passing through the air inlet per unit time, T3 is the third real-time temperature, T4 is the fourth real-time temperature, X is the ambient natural convection heat transfer coefficient, S is the surface area of ​​the tool shaft box that can dissipate heat to the air, T is the temperature of the tool shaft box, T5 is the fifth real-time temperature, λ is the thermal conductivity, A is the surface area of ​​the tool shaft box mounting bracket, T0 is the temperature of the machine tool bed, b is the thickness of the mounting bracket, and Q0 is other heat loss.

6. The method for determining the temperature of the cutter headbox according to claim 1, characterized in that: Based on the real-time temperature of the tool shaft box, the corresponding deformation amount of the tool shaft box is determined, and the tool displacement temperature compensation is performed based on the deformation amount.

7. A device for determining the temperature of a cutter shaft box, characterized in that, include: Host computer, data collector, and temperature acquisition unit; The host computer is connected to the data collector, and the data collector is connected to the temperature acquisition unit; The temperature acquisition unit is used to acquire the first real-time temperature at the water inlet of the electric spindle of the cutter shaft box, the second real-time temperature at the water outlet, the third real-time temperature at the air inlet, the fourth real-time temperature at the air outlet, and the fifth real-time temperature of the environment around the electric spindle. The data collector is used to collect the temperature values ​​acquired by the temperature acquisition unit and transmit them to the host computer system; The host computer is used to determine the formula for the remaining heat of the cutter shaft box based on the thermal balance relationship, to determine the formula for the temperature of the cutter shaft box based on the formula for the remaining heat of the cutter shaft box, and to substitute the first real-time temperature, the second real-time temperature, the third real-time temperature, the fourth real-time temperature and the fifth real-time temperature into the formula for the temperature of the cutter shaft box to determine the real-time temperature value of the cutter shaft box. The formula for the temperature of the cutter shaft box includes: ； Where: b is the thickness of the mounting bracket, I is the current of the electric spindle motor, R is the resistance, t is the running time of the electric spindle, and K i M is the heat generation coefficient of bearing i inside the cutter head box. i Let be the frictional torque of bearing i in the tool shaft box, j be the total number of bearings, n be the spindle speed, C1 be the specific heat capacity of the coolant, ρ1 be the density of the coolant, V1 be the flow rate of the coolant per unit time, T1 be the first real-time temperature, T2 be the second real-time temperature, Y be the heat absorption rate of the lubricating gas, m be the mass of lubricating gas passing through the air inlet per unit time, T3 be the third real-time temperature, T4 be the fourth real-time temperature, X be the ambient natural convection heat transfer coefficient, S be the surface area of ​​the tool shaft box that can dissipate heat to the air, T5 be the fifth real-time temperature, λ be the thermal conductivity, A be the surface area of ​​the tool shaft box mounting bracket, T0 be the temperature of the machine tool bed, C3 be the average specific heat capacity of the tool shaft box body, and m3 be the total mass of the tool shaft box.

8. The tool shaft box temperature determining device according to claim 7, characterized in that, The temperature acquisition unit includes: a first temperature sensor, a second temperature sensor, a third temperature sensor, a fourth temperature sensor, and a fifth temperature sensor; The first temperature sensor is installed at the water inlet of the electric spindle for connecting to the water chiller, and the first temperature sensor is used to collect the first real-time temperature; The second temperature sensor is installed at the outlet of the electric spindle for connecting to the water chiller, and the second temperature sensor is used to collect the second real-time temperature; The third temperature sensor is installed at the air inlet of the electric spindle for connecting to the oil-air lubrication device, and the third temperature sensor is used to collect the third real-time temperature. The fourth temperature sensor is installed at the air outlet of the electric spindle, and the fourth temperature sensor is used to collect the fourth real-time temperature. The fifth temperature sensor is installed at a predetermined distance outside the electric spindle, and the fifth temperature sensor is used to collect the fifth real-time temperature.

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