Boring and milling head for gantry numerical control machine tool

Abstract

The boring and milling head for the gantry numerical control machine tool belongs to the technical field of machine tool machining and comprises a shell, a main shaft is arranged in the shell, the two ends of the main shaft penetrate through the shell and extend to the outside, bearings are installed at the positions, close to the left end and the right end, of the side surface of the main shaft, and the bearings are arranged in the shell. A supporting base is installed on the outer circle face of the bearing and fixedly connected with the inner wall of the shell. The temperature sensor, the speed measurement sensor and the vibration sensor can monitor the temperature of the bearing and the rotating speed and the vibration amplitude of the main shaft in real time, data detected by the sensors are comprehensively processed, the prestress of the bearing is calculated and adjusted, and therefore the bearing is adjusted to the preset prestress in real time, and the service life of the bearing is prolonged. The pre-stress adjustment is more accurate, the boring and milling head can adapt to more complex machining environments, the adaptability of the boring and milling head to different machining conditions and working conditions is improved, and the stable machining performance under various conditions is guaranteed.

Description

Technical Field

[0001] The invention relates to the technical field of machine tool processing, and more specifically, to a boring and milling head for a gantry numerical control machine tool. Background Art

[0002] As an important accessory on CNC machine tools, the boring and milling head integrates the functions of boring and milling. It is usually installed on the spindle of the machine tool and realizes the processing of the workpiece through a precise transmission mechanism and control system. In terms of structure, the boring and milling head usually consists of a spindle, a cutter disc (or a tool mounting seat), a transmission device, a lubrication system, and a cooling system. Among them, the cutter disc (or tool mounting seat) is a component specially used to install various boring and milling cutters. According to different processing requirements, the operator can select a suitable tool and install it on the cutter disc for various boring and milling processes.

[0003] The spindle of the boring and milling head is generally equipped with bearings, but the bearings are the key components that support the spindle and allow it to rotate. They bear the various forces and torques generated by the spindle during operation. The bearings are usually composed of an outer ring, rolling elements (such as balls or rollers) and an inner ring, and there is a certain gap between these components. When installing the bearings, technicians generally apply a certain amount of prestress to the bearings in advance. The purpose of applying prestress is to make the rolling elements and raceways of the bearings fit more closely and eliminate the gap as much as possible. In this way, when the spindle is running, it can ensure that it works more stably and accurately, and effectively reduce the generation of vibration and noise. At the same time, the application of prestress can also improve the rigidity of the spindle, making it less likely to deform when subjected to large cutting forces, and can extend the service life of the spindle and bearings.

[0004] However, due to the pre-set prestress on the bearing, a series of complex physical phenomena will occur inside the bearing when the spindle rotates at high speed. The friction and rolling inside the bearing will generate a large amount of heat. This is due to the relative movement between the rolling elements and the raceways and the friction between the inner and outer rings of the bearing and the rolling elements. As the heat accumulates, the various parts of the bearing will experience thermal expansion. Due to the influence of thermal expansion, the fit between the rolling elements and the raceways will be tighter than the initial state, which actually increases the prestress of the bearing.

[0005] The increase in prestress will further intensify the friction inside the bearing, forming a vicious circle. On the one hand, the intensified friction will generate more heat, resulting in more obvious thermal expansion and further increase in prestress. On the other hand, the increased prestress and intensified friction will add additional resistance to the rotation of the spindle, affecting the spindle speed and rotation accuracy. In extreme cases, excessive prestress and friction may cause the bearing to overheat or even be damaged, thereby affecting the normal operation of the entire boring and milling head. Summary of the invention

[0006] Aiming at the problems existing in the prior art, the purpose of the present invention is to provide a boring and milling head for a gantry numerical control machine tool. By installing a temperature sensor, a speed sensor and a vibration sensor, the temperature of the bearing, the rotation speed of the spindle and the vibration amplitude can be monitored in real time. By comprehensively processing the data detected by the sensors, the prestress of the bearing is calculated and adjusted, so that the bearing is adjusted to the preset prestress in real time, making the prestress adjustment more accurate, being able to adapt to more complex machining environments, improving the adaptability of the boring and milling head to different machining conditions and working conditions, and ensuring stable machining performance under various conditions.

[0007] To solve the above problems, the present invention adopts the following technical solutions.

[0008] A boring and milling head for a gantry numerical control machine tool includes a housing. A spindle is arranged inside the housing, and both ends of the spindle penetrate through the housing and extend to the outside. Bearings are installed on the side surface of the spindle near the left and right ends. The bearings are arranged inside the housing. A support seat is installed on the outer circular surface of the bearing, and the support seat is fixedly connected to the inner wall of the housing;

[0009] An annular pressing plate is sleeved on the outer circular surface of the spindle. One end of the annular pressing plate abuts against the inner ring of the bearing, and the annular pressing plate is fixedly connected to the inner wall of the housing. Multiple sets of pressing blocks are arranged at the end of the bearing away from the annular pressing plate. One end of the pressing block abuts against the outer ring of the bearing, and an adjusting component is arranged at one end of the pressing block. The adjusting component is used to adjust the force of the pressing block on the outer ring of the bearing.

[0010] Further, the adjusting component includes a support ring. The support ring is arranged at the end of the bearing away from the annular pressing plate. The pressing block is slidably arranged on the outer circular surface of the support ring. A fixed disk is fixedly connected to the end of the support ring away from the bearing. The outer circular surface of the support ring is fixedly connected to the inner wall of the housing through an installation connecting rod. One end of the pressing block away from the bearing is designed as an inclined surface. An activity column is arranged on the inclined surface of the pressing block. One end of the activity column away from the pressing block passes through the fixed disk. An activity hole is opened at the position where the activity column penetrates through the pressing block. A rotating disk is arranged on the side of the fixed disk away from the support ring. A pressing groove is opened on the rotating disk. The number of the pressing grooves corresponds to the number of the activity columns. One end of the activity column away from the pressing block is arranged in the pressing groove. A control component is arranged at the edge of the rotating disk. The control component is used to control the rotation of the rotating disk.

[0011] Further, the control component includes a rack which is meshed and connected with the rotating disk. One end of the rack is fixedly connected with a two-way shape memory alloy wire. The end of the two-way shape memory alloy wire far away from the rack is fixedly connected with a heat conducting plate. One end of the heat conducting plate is fixedly connected to the support seat. Both the heat conducting plate and the support seat are made of heat conducting materials.

[0012] Further, the control component includes a gear which is meshed and connected with the rotating disk. A motor is installed on one side surface of the gear. The motor is fixedly connected to the inner wall of the housing through a motor base. One set of the pressing blocks is composed of a triangular block and a pressing block. A pressure sensor is embedded at the end of the pressing block far away from the bearing. The detection end of the pressure sensor is exposed outside the pressing block. The detection end of the pressure sensor is fixedly connected with a triangular block.

[0013] Further, a temperature sensor is embedded on the inner circular surface of the support seat. According to the temperature detected by the temperature sensor, the axial expansion amount of the bearing is calculated. According to the axial expansion amount of the bearing, the prestress that the bearing should be set is calculated.

[0014] Further, a speed sensor is arranged above the main shaft. The speed sensor is used to detect the rotation speed of the main shaft in real time. According to the measured rotation speed, the centrifugal force received by the rolling elements inside the bearing is calculated. According to the centrifugal force received by the rolling elements, the prestress that the bearing should be set is calculated.

[0015] Further, a vibration sensor is installed on the side surface of the support seat. The vibration sensor is used to detect the vibration amplitude of the main shaft in real time. According to the vibration amplitude, a relationship model between vibration and bearing prestress is constructed, and the prestress that the bearing should be set is calculated.

[0016] Further, the temperature factor of the bearing, the rotation speed factor of the main shaft, and the vibration amplitude factor are superimposed, and the prestress that the bearing should be set is comprehensively calculated.

[0017] Further, a prestress adjustment range of the bearing is set in advance. If the prestress adjustment of the bearing exceeds the prestress adjustment range, an alarm is triggered.

[0018] Further, a wireless receiving module and a wireless transmitting module are also installed on the housing.

[0019] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0020] This solution can monitor the temperature of the bearing, the rotation speed of the spindle, and the vibration amplitude in real time by installing temperature sensors, speed sensors, and vibration sensors. By comprehensively processing the data detected by the sensors, calculating, and adjusting the prestress of the bearing, the bearing can be adjusted to the preset prestress in real time, making the prestress adjustment more accurate, capable of adapting to more complex machining environments, improving the adaptability of the boring and milling head to different machining conditions and working conditions, and ensuring stable machining performance under various conditions. Brief Description of the Drawings

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0022] Figure 1 is the external view of the overall structure of the present invention;

[0023] Figure 2 is the schematic diagram of the internal structure of the housing of the present invention;

[0024] Figure 3 is the split view of the adjustment component in the first embodiment of the present invention;

[0025] Figure 4 For the present invention Figure 3 is the enlarged view of part A in;

[0026] Figure 5 is the partial structure schematic diagram in the second embodiment of the present invention;

[0027] Figure 6 is the structure schematic diagram of the pressure sensor in the second embodiment of the present invention;

[0028] Figure 7 is the structure schematic diagram of the support base of the present invention.

[0029] Explanation of the reference numerals in the drawings:

[0030] 1. Housing; 2. Spindle; 3. Support base; 4. Bearing; 5. Annular abutting plate; 6. Support ring; 7. Tightening block; 8. Fixed disk; 9. Moving hole; 10. Rotating disk; 11. Extrusion groove; 12. Moving column; 13. Rack; 14. Bimetallic wire; 15. Gear; 16. Motor; 17. Triangular block; 18. Pressure sensor; 19. Extrusion block; 20. Vibration sensor; 21. Temperature sensor; 22. Heat conducting plate; 23. Speed sensor. Detailed Embodiments

[0031] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention; obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0032] Embodiment 1

[0033] Please refer to Figures 1 to 4 , a boring and milling head for a gantry numerical control machine tool, which includes a housing 1. A main shaft 2 is arranged inside the housing 1, and both ends of the main shaft 2 penetrate through the housing 1 and extend to the outside. Bearings 4 are installed at positions near the left and right ends of the outer surface of the main shaft 2. The bearings 4 are arranged inside the housing 1. A support seat 3 is installed on the outer circumferential surface of the bearings 4, and the support seat 3 is fixedly connected to the inner wall of the housing 1; an annular pressing plate 5 is sleeved on the outer circumferential surface of the main shaft 2. One end of the annular pressing plate 5 abuts against the inner ring of the bearing 4, and the annular pressing plate 5 is fixedly connected to the inner wall of the housing 1. Multiple sets of pressing blocks 7 are arranged at one end of the bearing 4 away from the annular pressing plate 5. One end of the pressing block 7 abuts against the outer ring of the bearing 4. An adjusting component is arranged at one end of the pressing block 7, and the adjusting component is used to adjust the force of the pressing block 7 on the outer ring of the bearing 4.

[0034] The adjusting component includes a support ring 6. The support ring 6 is arranged at one end of the bearing 4 away from the annular pressing plate 5. The pressing block 7 is slidably arranged on the outer circumferential surface of the support ring 6. A fixing plate 8 is fixedly connected to one end of the support ring 6 away from the bearing 4. The outer circumferential surface of the support ring 6 is fixedly connected to the inner wall of the housing 1 through mounting connecting rods. One end of the pressing block 7 away from the bearing 4 is designed with an inclined surface. An activity column 12 is arranged on the inclined surface of the pressing block 7. One end of the activity column 12 away from the pressing block 7 passes through the fixing plate 8. An activity hole 9 is opened at the position where the activity column 12 penetrates on the pressing block 7. A rotating disk 10 is arranged on the side of the fixing plate 8 away from the support ring 6. An extrusion groove 11 is opened on the rotating disk 10. The number of the extrusion grooves 11 corresponds to the number of the activity columns 12. One end of the activity column 12 away from the pressing block 7 is arranged in the extrusion groove 11. A control component is arranged at the edge of the rotating disk 10, and the control component is used to control the rotation of the rotating disk 10;

[0035] The control component includes a rack 13. The rack 13 is meshed with the rotating disk 10. One end of the rack 13 is fixedly connected to a two-way shape memory alloy wire 14. One end of the two-way shape memory alloy wire 14 away from the rack 13 is fixedly connected to a heat conducting plate 22. One end of the heat conducting plate 22 is fixedly connected to the support seat 3. Both the heat conducting plate 22 and the support seat 3 are made of heat conducting materials.

[0036] When the boring and milling head is working, the main shaft 2 in the housing 1 is driven by an external motor. When the main shaft 2 is working, it drives the inner ring of the bearing 4 and the internal rolling elements to rotate. After working for a period of time, heat is generated in the bearing 4 due to internal friction. As the heat accumulates, the temperature of the bearing 4 gradually rises. The temperature of the bearing 4 is transmitted to the support seat 3, and the temperature of the support seat 3 is transmitted to the two-way shape memory alloy wire 14 through the heat conduction plate 22. When the temperature reaches the temperature at which the two-way shape memory alloy wire 14 changes its deformation, the two-way shape memory alloy wire 14 contracts and drives the rack 13 to move at the same time. The movement of the rack 13 drives the rotation of the rotating disk 10. When the rotating disk 10 rotates, it drives the extrusion groove 11 to rotate synchronously. By rotating the extrusion groove 11, the extrusion force on the movable column 12 by the extrusion groove 11 is changed, driving the movable column 12 to move upward to reduce the extrusion force on the movable column 12. The right end of the movable column 12 is pressed against the inclined surface of the abutting block 7. The extrusion force of the movable column 12 on the inclined surface of the abutting block 7 decreases, and correspondingly, the extrusion force of the abutting block 7 on the outer ring of the bearing 4 also decreases. Since the annular abutting plate 5 is always pressed against the inner ring of the bearing 4, by changing the extrusion force of the abutting block 7 on the outer ring of the bearing 4, the prestress on the bearing 4 is changed, ensuring that the prestress of the bearing 4 can be automatically adjusted according to the working conditions of the bearing 4, thereby ensuring the normal operation of the boring and milling head. After the boring and milling head stops working and stands still for a period of time, the temperature of the bearing 4 will decrease. Correspondingly, the temperatures of the support seat 3, the heat conduction plate 22, and the two-way shape memory alloy wire 14 will also decrease. When the temperature drops below the deformation temperature of the two-way shape memory alloy wire 14, the two-way shape memory alloy wire 14 elongates and simultaneously pushes the rack 13 to move in the reverse direction. The reverse movement of the rack 13 drives the rotating disk 10 to move in the reverse direction as well. At this time, the extrusion groove 11 on the rotating disk 10 squeezes the movable column 12 to move downward. The right end of the movable column 12 presses the inclined surface of the abutting block 7, causing the abutting block 7 to have a force to move to the right, thereby realizing the effect of increasing the tightening force on the bearing 4 and automatically adjusting the pre-tightening force of the bearing 4 according to the temperature change of the bearing 4.

[0037] Embodiment 2

[0038] As Figures 2 to 7 shown, the control component includes a gear 15. The gear 15 is meshed and connected with the rotating disk 10. A motor 16 is installed on one side surface of the gear 15. The motor 16 is fixedly connected to the inner wall of the housing 1 through a motor seat. One group of the abutting blocks 7 is composed of a triangular block 17 and an extrusion block 19. A pressure sensor 18 is embedded at one end of the extrusion block 19 away from the bearing 4. The detection end of the pressure sensor 18 is exposed outside the extrusion block 19. The detection end of the pressure sensor 18 is fixedly connected to the triangular block 17;

[0039] A temperature sensor 21 is embedded and installed on the inner circular surface of the support base 3. According to the temperature detected by the temperature sensor 21, the axial expansion amount of the bearing 4 is calculated, and the prestress that the bearing 4 should be set is calculated according to the axial expansion amount of the bearing 4.

[0040] In Embodiment 2, the adjustment of the prestress of the bearing 4 is more precise than that in Embodiment 1. When the temperature of the bearing 4 exceeds the upper limit of the normal range, it is determined that the prestress of the bearing 4 increases due to thermal expansion, and the prestress adjustment program is started. First, according to the collected real-time temperature data and combined with the thermal expansion characteristics of the bearing 4, the value of the prestress that needs to be adjusted for the bearing 4 at the current temperature is calculated. According to the thermal expansion theory, the radial dimension change amount of the bearing 4 caused by the temperature change can be calculated by the following formula: , where is the nominal outer diameter of the bearing 4 at the initial temperature , is the linear expansion coefficient of the bearing 4 material, , is the currently measured temperature. According to the Hertz contact theory, the relationship between the radial prestress change of the bearing 4 caused by thermal expansion and the dimension change amount is obtained as , where is the comprehensive elastic modulus of the materials of the bearing 4 and the support base 3, which can be calculated by the formula , where , are the elastic moduli of the materials of the bearing 4 and the support base 3 respectively; is the Poisson's ratio, which is generally between 0.25 and 0.35 for common metal materials; , are the outer ring curvature radius of the bearing 4 and the inner hole curvature radius of the support base 3 respectively. In the initial state, the prestress of the bearing 4 is , then the prestress that needs to be adjusted at the current temperature is: .

[0041] After determining the prestress that the bearing 4 needs to be adjusted to, at this time, the motor 16 is controlled to rotate the gear 15 forward and backward. By rotating the gear 15 forward and backward, the rotating disk 10 can be driven to rotate forward and backward. By driving the rotating disk 10 to rotate forward and backward, the extrusion force of the movable column 12 on the pressing block 7 is controlled. Because the extrusion of one group of movable columns 12 acts on the triangular block 17, the force received by the triangular block 17 will act on the pressure sensor 18, and the value detected by the pressure sensor 18 is the prestress applied by the pressing block 7 to the bearing 4. During the process of adjusting the prestress of the bearing 4, if the value detected by the pressure sensor 18 reaches At this value, the adjustment of the prestress of the bearing 4 is stopped. Through the detection and automatic control of the sensor, compared with the shape memory alloy to dynamically adjust the preload of the bearing 4, it is more accurate.

[0042] Embodiment 3

[0043] As Figures 2 to 7 shown, a speed sensor 23 is arranged above the main shaft 2. The speed sensor 23 is used to detect the rotation speed of the main shaft 2 in real time, calculate the centrifugal force received by the rolling elements inside the bearing 4 according to the measured rotation speed, and calculate the prestress that the bearing 4 should be set according to the centrifugal force received by the rolling elements.

[0044] When the main shaft 2 rotates from low speed to high speed, the rolling elements in the bearing 4 generate additional forces due to centrifugal force. The centrifugal force received by a single rolling element can be calculated by the following formula: , where is the mass of a single rolling element, which can be obtained from the bearing 4 sample; is the radius of the center circle of the rolling elements, which is determined by the structure of the bearing 4; is the angular velocity, , is the rotation speed of the main shaft 2; The centrifugal force will cause the contact angle between the rolling elements and the raceway of the bearing 4 to change, thereby affecting the prestress. According to the Hertz contact stress calculation formula and the structure of the bearing 4, the change in the radial prestress caused by the change in rotation speed and the centrifugal force The relationship is: , where, is a coefficient related to the structure and material of the bearing 4, which can be determined by finite element analysis; is the initial contact angle, which is given by the design of the bearing 4; is the contact angle after the action of centrifugal force, which is related to the centrifugal force, the structural parameters of the bearing 4, etc. For the sake of simplifying the calculation, within the preset rotation speed range, it can be approximately considered that and are linearly related: , is a coefficient related to the structure of the bearing 4; In the initial state, the prestress of the bearing 4 is , then the prestress that needs to be adjusted at the current rotation speed .

[0045] After determining the prestress that the bearing 4 needs to be adjusted to, the prestress of the bearing 4 can be adjusted according to the control method of the motor 16 in Embodiment 2. When the value detected by the pressure sensor 18 reaches the adjusted prestress, the motor 16 is controlled to stop rotating, so as to achieve the precise adjustment of the prestress of the bearing 4 according to the rotation speed of the main shaft 2.

[0046] Example 4

[0047] As Figures 2 to 7 shown, a vibration sensor 20 is installed on the side surface of the support base 3. The vibration sensor 20 is used to detect the vibration amplitude of the main shaft 2 in real time. According to the vibration amplitude, a relationship model between vibration and the prestress of the bearing 4 is constructed, and the prestress that should be set for the bearing 4 is calculated.

[0048] When the vibration amplitude of the main shaft 2 is higher than the upper limit of the preset normal range value, the main shaft 2 can be stabilized by changing the internal clearance space of the bearing 4. Changing the internal clearance space of the bearing 4 can be achieved by changing the prestress of the bearing 4. The main shaft 2 can be simplified into a multi-degree-of-freedom vibration model, where the bearing 4 is a key support component, and its stiffness has an important influence on the vibration response of the system. In the case of small deformation, the vibration acceleration at the support base 3 and the dynamic stiffness of the bearing 4 have the following relationship: * , where is the excitation force causing vibration, which is mainly generated by factors such as cutting force during the operation of the boring and milling head; is the equivalent mass of the vibration system, including the mass of the main shaft 2, the tool, and the vibrating bearing 4, etc.; is the rotational angular velocity of the main shaft 2, , x is the rotational speed of the main shaft 2; is the natural frequency of the system, where ; is the damping ratio of the system, which is determined by factors such as the bearing 4, the support base 3, and the structural damping of the whole system. The dynamic stiffness of the bearing 4 and the prestress have a complex non-linear relationship. The following formula can be established to describe the relationship between the two (taking cylindrical roller bearings as an example): , where is the initial dynamic stiffness of the bearing 4 under zero prestress, which can be obtained through experimental testing; and are coefficients related to the structure, material, and working conditions of the bearing 4, and are generally determined by experimental fitting. For common cylindrical roller bearings, has a value range of 0.01 - 0.1, has a value range of 0.5 - 0.8.

[0049] When the vibration acceleration When the preset value is exceeded, in order to reduce the vibration acceleration to a reasonable range, it is necessary to increase the bearing prestress. By combining the above two formulas and performing a series of mathematical transformations, the prestress required to be adjusted under the current vibration state can be obtained. The calculation formula is: In practical applications, It is difficult to measure directly, but its value can be estimated by establishing a cutting force model or using empirical formulas based on the working parameters of the boring and milling head (such as cutting depth, feed speed, tool material and workpiece material, etc.); and It can be obtained through experimental modal analysis. After the system parameters are determined, the vibration acceleration collected in real time can be Calculate the required prestressing force of bearing 4 .

[0050] After determining the prestress to which the bearing 4 needs to be adjusted, the prestress of the bearing 4 can be adjusted according to the control method of the motor 16 in Example 2. When the value detected by the pressure sensor 18 reaches the adjusted prestress, the motor 16 is controlled to stop rotating, thereby achieving precise adjustment of the prestress of the bearing 4 according to the vibration amplitude of the spindle 2, thereby stabilizing the operation of the spindle 2 and ensuring the accuracy of the processed workpiece.

[0051] Example 5

[0052] like Figures 2 to 7 As shown, the temperature factor of the bearing 4 and the speed factor and vibration amplitude factor of the main shaft 2 are superimposed, and the prestress that should be set for the bearing 4 is comprehensively calculated.

[0053] The initial prestress is , the required prestress after combining the three factors needs to be considered and adjusted for the weight of each factor, and the weight coefficient can be introduced , , ,and , the weight coefficient can be determined by experimental testing or finite element analysis, and optimized and adjusted under different working conditions; Expressed as the weight coefficient of the temperature factor; is the weight coefficient of the speed factor; is the weight coefficient of the vibration factor; then , It indicates the prestress adjustment amount of the bearing 4 under the temperature factor, which is calculated in Example 2. ; It indicates the prestress adjustment amount of the bearing 4 under the spindle 2 speed factor, which is calculated in Example 3. ; Indicates the amount of prestress adjustment of the bearing 4 under the influence of the vibration amplitude factor of the main shaft 2, that is, the value calculated in Embodiment 4 .

[0054] After obtaining according to the comprehensive factors , the prestress of the bearing 4 can be adjusted according to the control method of the motor 16 in Embodiment 2. When the value detected by the pressure sensor 18 reaches the adjusted prestress, the motor 16 is controlled to stop rotating. The prestress of the bearing 4 is adjusted comprehensively according to the influence of various factors, which is more accurate than the prestress adjustment of the bearing 4 in Embodiments 1-4, realizing that the prestress of the bearing 4 can be adjusted in real time and dynamically during the working process of the boring and milling head, ensuring the machining accuracy of the boring and milling head for the workpiece.

[0055] Set in advance the prestress adjustment range of the bearing 4. If the prestress adjustment of the bearing 4 exceeds the prestress adjustment range, an alarm is triggered. The alarm can be a buzzer sound, LED light flashing, etc., so that the staff can timely discover problems inside the boring and milling head and need to stop the machine for inspection and maintenance.

[0056] A wireless receiving module and a wireless transmitting module are also installed on the housing 1. Through the wireless receiving module and the wireless transmitting module, the alarm information can be sent to the mobile terminal used by the staff, such as the staff's mobile phone, etc. The temperature of the bearing 4, the rotation speed and rotation amplitude of the main shaft 2 can also be understood in real time through the mobile phone.

[0057] The above is only a preferred specific embodiment of the present invention; however, the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution of the present invention and its improved concept, makes equivalent substitutions or changes, and should be covered by the protection scope of the present invention.

Claims

1. A boring and milling head for a gantry numerical control machine tool, comprising a housing (1). A main shaft (2) is arranged inside the housing (1), and both ends of the main shaft (2) penetrate through the housing (1) and extend to the outside. Bearings (4) are installed at positions near the left and right ends of the side surface of the main shaft (2). The bearings (4) are arranged inside the housing (1). A support seat (3) is installed on the outer circumferential surface of the bearings (4), and the support seat (3) is fixedly connected to the inner wall of the housing (1). It is characterized in that: An annular abutting plate (5) is sleeved on the outer circumferential surface of the main shaft (2). One end of the annular abutting plate (5) abuts against the inner ring of the bearing (4), and the annular abutting plate (5) is fixedly connected to the inner wall of the housing (1). Multiple sets of abutting blocks (7) are arranged at one end of the bearing (4) away from the annular abutting plate (5). One end of the abutting block (7) abuts against the outer ring of the bearing (4), and an adjusting component is arranged at one end of the abutting block (7). The adjusting component is used to adjust the force of the abutting block (7) on the outer ring of the bearing (4).

2. A boring and milling head for a gantry CNC machine tool according to claim 1, characterized in that: The adjusting component includes a support ring (6). The support ring (6) is arranged at one end of the bearing (4) away from the annular abutting plate (5). The abutting block (7) is slidably arranged on the outer circumferential surface of the support ring (6). A fixing disk (8) is fixedly connected to one end of the support ring (6) away from the bearing (4). The outer circumferential surface of the support ring (6) is fixedly connected to the inner wall of the housing (1) through an installation connecting rod. One end of the abutting block (7) away from the bearing (4) is designed as an inclined surface, and a movable column (12) is arranged on the inclined surface of the abutting block (7). One end of the movable column (12) away from the abutting block (7) penetrates through the fixing disk (8). A movable hole (9) is opened at the position where the movable column (12) penetrates through the abutting block (7). A rotating disk (10) is arranged on the side of the fixing disk (8) away from the support ring (6). An extrusion groove (11) is opened on the rotating disk (10). The number of the extrusion grooves (11) corresponds to the number of the movable columns (12). One end of the movable column (12) away from the abutting block (7) is arranged in the extrusion groove (11). A control component is arranged at the edge of the rotating disk (10). The control component is used to control the rotation of the rotating disk (10).

3. A boring and milling head for a gantry CNC machine tool according to claim 2, characterized in that: The control component includes a rack (13). The rack (13) is meshed with the rotating disk (10). One end of the rack (13) is fixedly connected to a two-way shape memory alloy wire (14). One end of the two-way shape memory alloy wire (14) away from the rack (13) is fixedly connected to a heat conducting plate (22). One end of the heat conducting plate (22) is fixedly connected to the support seat (3). Both the heat conducting plate (22) and the support seat (3) are made of heat conducting materials.

4. A boring and milling head for a gantry numerical control machine tool according to claim 2, characterized in that: The control component includes a gear (15), the gear (15) is meshed and connected with a rotating disk (10), a motor (16) is installed on one side surface of the gear (15), and the motor (16) is fixedly connected with the inner wall of the housing (1) through a motor base. One set of the pressing blocks (7) is composed of a triangular block (17) and a pressing block (19). A pressure sensor (18) is embedded at one end of the pressing block (19) away from the bearing (4). The detection end of the pressure sensor (18) is exposed outside the pressing block (19), and the detection end of the pressure sensor (18) is fixedly connected with the triangular block (17).

5. A boring and milling head for a gantry numerically controlled machine tool according to claim 4, characterized in that: A temperature sensor (21) is embedded on the inner circular surface of the support seat (3). According to the temperature detected by the temperature sensor (21), the axial expansion amount of the bearing (4) is calculated, and the prestress that should be set for the bearing (4) is calculated according to the axial expansion amount of the bearing (4).

6. A boring and milling head for a gantry CNC machine tool according to claim 5, characterized in that: A speed sensor (23) is arranged above the main shaft (2). The speed sensor (23) is used to detect the rotation speed of the main shaft (2) in real time. According to the measured rotation speed, the centrifugal force received by the rolling elements inside the bearing (4) is calculated, and the prestress that should be set for the bearing (4) is calculated according to the centrifugal force received by the rolling elements.

7. A boring and milling head for a gantry numerical control machine tool according to claim 6, characterized in that: A vibration sensor (20) is installed on the side surface of the support seat (3). The vibration sensor (20) is used to detect the vibration amplitude of the main shaft (2) in real time. According to the vibration amplitude, a relationship model between vibration and the prestress of the bearing (4) is constructed, and the prestress that should be set for the bearing (4) is calculated.

8. A boring and milling head for a gantry CNC machine tool according to claim 7, characterized in that: The temperature factor of the bearing (4), the rotation speed factor of the main shaft (2), and the vibration amplitude factor are superimposed, and the prestress that should be set for the bearing (4) is comprehensively calculated.

9. The boring and milling head for a gantry CNC machine tool according to claim 8, wherein: The prestress adjustment range of the bearing (4) is set in advance. If the prestress adjustment of the bearing (4) exceeds the prestress adjustment range, an alarm is triggered.

10. A boring and milling head for a gantry numerical control machine tool according to claim 9, characterized in that: A wireless receiving module and a wireless transmitting module are also installed on the housing (1).

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