Four-axis unit numerical control machining center

Abstract

The invention discloses a four-axis unit numerical control machining center, and belongs to the field of numerical control machining, the four-axis unit numerical control machining center comprises a numerical control center main body, a Y-axis moving guide rail is arranged on a bottom platform of the numerical control center main body, and an X-axis moving guide rail is fixedly arranged on the Y-axis moving guide rail; a Z-axis moving guide rail is fixedly connected to one side of the numerical control center body, the numerical control center body is movably connected with a cutter driving module through the Z-axis moving guide rail, a fourth axis assembly is fixedly connected to the X-axis moving guide rail, and a levelness leveling assembly used for leveling the fourth axis assembly is detachably connected to the lower end of the cutter main shaft. By arranging the levelness leveling assembly and the hydraulic supporting assembly, firstly, when the planeness of the reference surface of the large bridge plate is detected, the planeness does not need to be manually detected by using a dial indicator in multiple regions, automatic detection is achieved, operation steps are simplified, meanwhile, subjective degree errors caused by manual detection are avoided, and the detection efficiency is improved. And the leveling efficiency is improved.

Description

Technical Field

[0001] The present invention relates to the field of numerical control machining, and more specifically, to a four-axis unit numerical control machining center. Background Art

[0002] Four-axis numerical control machining center: Based on the traditional three-axis (X, Y, Z) machining, a rotating axis is added. This rotating axis can be the A axis rotating around the X axis, the B axis rotating around the Y axis, or the C axis rotating around the Z axis. This rotating axis enables the machining platform to rotate, so that the machine tool can complete more automated machining operations during the machining process. The four-axis machining center belongs to an advanced model of the three-axis machining center, which can realize multi-sided machining, reduce the number of clamping times, and improve the machining efficiency.

[0003] During the machining cycle of the four-axis numerical control machining center, to ensure the machining accuracy and equipment stability, it is necessary to level the fourth-axis bridge plate relatively frequently according to factors such as machining frequency and load intensity, environmental temperature and humidity fluctuations, material characteristics and stress release, etc. For example, during high-frequency machining, the bridge plate is leveled once every 20 - 30 parts; when the temperature change > 5°C or the humidity fluctuation > 30%, the bridge plate is prone to thermal expansion and contraction, and an additional leveling operation needs to be added before changing shifts, etc.

[0004] When leveling the fourth-axis bridge plate, usually the following three steps are required: 1. Detect the flatness of the bridge plate reference surface; 2. Detect the Z-axis rotation center; 3. Detect the Y-axis rotation center; During the actual leveling process, for large bridge plates, when detecting the flatness of the bridge plate reference surface, it is usually necessary to use a dial indicator to detect the flatness in multiple regions (500 mm) and then gradually adjust. The operation steps are cumbersome (such as the dial indicator needs to be repeatedly moved and data recorded), and the leveling efficiency is low. In addition, for large bridge plates, due to the large span of the bridge plate, affected by its own weight, local bending deformation is likely to occur at the mid-span position, resulting in easy error in the flatness after calibration and affecting the machining accuracy. Summary of the Invention

[0005] Aiming at the problems existing in the prior art, the purpose of the present invention is to provide a four-axis unit numerical control machining center.

[0006] To solve the above problems, the present invention adopts the following technical solutions.

[0007] A four-axis unit numerical control machining center, including a numerical control center main body. The bottom platform of the numerical control center main body is provided with a Y-axis moving guide rail, and an X-axis moving guide rail is fixedly arranged on the Y-axis moving guide rail; one side of the numerical control center main body is fixedly connected with a Z-axis moving guide rail, and the numerical control center main body is movably connected with a tool driving module through the Z-axis moving guide rail. The lower end of the tool driving module is fixedly connected with a tool spindle. A fourth-axis assembly is fixedly connected to the X-axis moving guide rail, and a levelness leveling assembly for leveling the fourth-axis assembly is detachably connected to the lower end of the tool spindle.

[0008] Furthermore, the levelness leveling assembly includes a main connecting rod and a processing unit. A connecting portion is provided on the main connecting rod and is detachably connected to the tool spindle through the connecting portion. The connection between the connecting portion and the tool spindle can be either a threaded connection or a hydraulic clamping connection; a fixed substrate is fixedly connected to the bottom of the main connecting rod. On one side of the bottom of the fixed substrate, there is an X-axis ball screw drive guide rail, and a second digital display dial indicator is fixedly connected to the bottom of the X-axis ball screw drive guide rail. A number of rough leveling assemblies are evenly distributed and fixedly connected to the other side of the bottom of the fixed substrate. A Y-axis ball screw drive guide rail is provided at the left end of the fixed substrate, and a first digital display dial indicator is fixedly connected to the bottom of the Y-axis ball screw drive guide rail. A battery pack is also provided on the front side of the fixed substrate.

[0009] Furthermore, the rough leveling assembly includes a cylinder fixedly connected to the bottom of the fixed substrate. A cylinder body is fixedly connected to the bottom of the cylinder. Two groups of limiting plates are symmetrically and fixedly connected to the middle position inside the cylinder body. Two groups of springs are symmetrically fixedly installed on the opposite sides of the two groups of limiting plates. An activity plate is fixedly connected to the middle position between the two groups of springs, and the activity plate is slidably connected to the inner wall of the cylinder body. A top rod is fixedly connected to the middle position of the activity plate, and the upper and lower ends of the top rod respectively penetrate through the two groups of limiting plates and are slidably connected to the limiting plates; an extrusion plate is fixedly connected to the top end of the top rod, and a pressure sensor is fixedly connected to the inner top surface of the cylinder body; the bottom end of the top rod extends to the outside of the cylinder body and is fixedly connected to a contact ball.

[0010] Furthermore, the fourth-axis assembly includes a tailstock and a fixed seat fixedly connected to the X-axis moving guide rail. A bridge plate is rotatably connected between the tailstock and the fixed seat. A fourth-axis rotating motor is provided on one side of the tailstock to drive the bridge plate to rotate.

[0011] Furthermore, a hydraulic support assembly is also fixedly connected to the upper surface of the X-axis moving guide rail corresponding to the middle position of the bridge plate. The hydraulic support assembly includes a base fixedly connected to the upper surface of the X-axis moving guide rail. A number of hydraulic support rods are evenly and fixedly distributed on the base. A flexible gasket is provided at the upper ends of the hydraulic support rods. The flexible gasket is made of polyurethane material, and the flexible gasket abuts against the lower surface of the bridge plate.

[0012] Furthermore, the processing unit is used to calculate the angle that the fourth-axis rotating motor needs to adjust the bridge plate based on the levelness data real-time collected by the first digital display dial indicator; calculate the Y-axis deformation span value S of the deformation position of the bridge plate according to the deformation data detected by the rough leveling assembly Y ; detect the X-axis deformation span value S of the deformation position through the second digital display dial indicator X and the Z-axis coordinate Z of the maximum deformation point M ; utilize the Y-axis deformation span value S of the deformation position of the bridge plateY and the X-axis deformation span value S X Find the center of the bridge plate deformation position and correspond it to the hydraulic support rods in the corresponding area, calculate the compensation amount of the hydraulic support rods and perform compensation.

[0013] Furthermore, calculate the angle that the fourth-axis rotation motor needs to adjust the bridge plate from the levelness data collected by the first digital display dial indicator in real time, including: Pull the first digital display dial indicator along the Y-axis of the bridge plate for a certain distance. Let the spatial coordinates of the first contact point be, and the spatial coordinates of the last contact point be. Establish a formula to obtain the rotation angle of the bridge plate axis, and use the fourth-axis rotation motor for corresponding adjustment.

[0014] Furthermore, calculate the Y-axis deformation span value S of the bridge plate deformation position according to the deformation data detected by the rough leveling component Y , including: Move all the rough leveling components along the Y-axis of the bridge plate. If the horizontal reference plane of the bridge plate after preliminary leveling deforms due to gravity, the pressure signal of the pressure sensor will disappear during the movement of the rough leveling components. Calculate the Y-axis deformation span value S according to the disappearance time and the movement speed of the rough leveling components Y .

[0015] Furthermore, detect the X-axis deformation span value S of the deformation position through the second digital display dial indicator X and the Z-axis coordinate Z of the maximum deformation point M , including: Use the X-axis ball screw to drive the guide rail to move the second digital display dial indicator along the X-axis and at the central position in the Y-axis direction at the deformation point to obtain the X-axis deformation span value S at the deformation point X and the Z-axis coordinate Z of the maximum deformation point M .

[0016] Furthermore, use the Y-axis deformation span value S of the bridge plate deformation position Y and the X-axis deformation span value S X Find the center of the bridge plate deformation position and correspond it to the hydraulic support rods in the corresponding area, calculate the compensation amount of the hydraulic support rods and perform compensation, including: The processing unit obtains the Y-axis deformation span value S of the deformation position Y and the X-axis deformation span value S X , calculate the center of the bridge plate deformation position, correspond it to the hydraulic support rods in the corresponding area, calculate the required Z-axis hydraulic support rod compensation amount at the deformation position and perform compensation.

[0017] Compared with the prior art, the beneficial effects of the present invention: By providing a levelness leveling component and a hydraulic support component, when detecting the flatness of the reference surface of a large bridge plate, it is no longer necessary to manually use a dial indicator to detect the flatness in multiple sub-areas. This realizes automated detection, simplifies the operation steps, and at the same time avoids the subjective error in readings caused by manual detection, improving the leveling efficiency. At the same time, by providing a hydraulic support component to compensate and support the bridge plate, the situation of deformation of the bridge plate due to gravity is further avoided, improving the numerical control machining accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 is a schematic diagram of the overall structure of the present invention; Figure 2 is a schematic diagram of the structure of the fourth-axis component of the present invention; Figure 3 is an enlarged schematic diagram of the levelness leveling component of the present invention; Figure 4 is a cross-sectional schematic diagram of the rough leveling component of the present invention; Figure 5 is a schematic diagram of the structure of the hydraulic support component of the present invention.

[0019] Explanation of the reference numerals in the drawings: 1, main body of the numerical control center; 2, X-axis moving guide rail; 3, Y-axis moving guide rail; 4, fourth-axis component; 41, tailstock; 42, bridge plate; 43, fixed seat; 44, fourth-axis rotating motor; 5, levelness leveling component; 51, connecting part; 52, main connecting rod; 53, Y-axis ball screw drive guide rail; 54, first digital display dial indicator; 55, rough leveling component; 551, cylinder; 552, cylinder body; 553, limiting plate; 554, movable plate; 556, contact ball; 557, ejector rod; 560, spring; 561, pressing plate; 562, pressure sensor; 56, battery pack; 57, fixed base plate; 58, X-axis ball screw drive guide rail; 59, second digital display dial indicator; 6, tool spindle; 7, tool drive module; 8, Z-axis moving guide rail; 9, hydraulic support component; 91, flexible gasket; 92, hydraulic support rod; 93, base. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0020] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to 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.

[0021] Please refer to Figures 1 to 5 , a four-axis unit CNC machining center, including a CNC center main body 1. A Y-axis moving guide rail 3 is provided on the bottom platform of the CNC center main body 1, and an X-axis moving guide rail 2 is fixedly provided on the Y-axis moving guide rail 3; on one side of the CNC center main body 1, a Z-axis moving guide rail 8 is fixedly connected, and the CNC center main body 1 is movably connected to a tool driving module 7 through the Z-axis moving guide rail 8. The lower end of the tool driving module 7 is fixedly connected to a tool spindle 6; A fourth-axis assembly 4 is fixedly connected to the X-axis moving guide rail 2, and a levelness leveling assembly 5 for leveling the fourth-axis assembly 4 is detachably connected to the lower end of the tool spindle 6.

[0022] As Figure 3 and Figure 4 shown, the levelness leveling assembly 5 includes a main connecting rod 52 and a processing unit. A connecting portion 51 is provided on the main connecting rod 52 and is detachably connected to the tool spindle 6 through the connecting portion 51. The connection between the connecting portion 51 and the tool spindle 6 can be selected as one of threaded connection or hydraulic clamping connection; a fixed substrate 57 is fixedly connected to the bottom of the main connecting rod 52. On one side of the bottom of the fixed substrate 57, an X-axis ball screw driving guide rail 58 is provided, and a second digital display dial indicator 59 is fixedly connected to the bottom of the X-axis ball screw driving guide rail 58. A plurality of rough leveling assemblies 55 are evenly distributed and fixedly connected to the other side of the bottom of the fixed substrate 57. A Y-axis ball screw driving guide rail 53 is provided at the left end of the fixed substrate 57, and a first digital display dial indicator 54 is fixedly connected to the bottom of the Y-axis ball screw driving guide rail 53. A battery pack 56 is further provided on the front side of the fixed substrate 57.

[0023] As Figure 4 shown, the rough leveling assembly 55 includes a column 551 fixedly connected to the bottom of the fixed substrate 57. A cylinder 552 is fixedly connected to the bottom of the column 551. Two groups of limiting plates 553 are symmetrically and fixedly connected to the middle position inside the cylinder 552. Two groups of springs 560 are symmetrically fixedly installed on the opposite sides of the two groups of limiting plates 553. A movable plate 554 is fixedly connected to the middle position between the two groups of springs 560, and the movable plate 554 is slidably connected to the inner wall of the cylinder 552. A top rod 557 is fixedly connected to the middle position of the movable plate 554. The upper and lower ends of the top rod 557 respectively penetrate through the two groups of limiting plates 553 and are slidably connected to the limiting plates 553; an extrusion plate 561 is fixedly connected to the top end of the top rod 557, and a pressure sensor 562 is fixedly connected to the inner top surface of the cylinder 552; the bottom end of the top rod 557 extends to the outside of the cylinder 552 and is fixedly connected to a contact ball 556.

[0024] As Figure 2As shown in the figure, the fourth-axis assembly 4 includes a tailstock 41 and a fixed seat 43 fixedly connected to the X-axis moving guide rail 2. A bridge plate 42 is rotatably connected between the tailstock 41 and the fixed seat 43. A fourth-axis rotating motor 44 is provided on one side of the tailstock 41 to drive the rotation of the bridge plate 42.

[0025] As Figure 5 shown, a hydraulic support assembly 9 is also fixedly connected to the upper surface of the X-axis moving guide rail 2 corresponding to the middle position of the bridge plate 42. The hydraulic support assembly 9 includes a base 93 fixedly connected to the upper surface of the X-axis moving guide rail 2. A number of hydraulic support rods 92 are evenly and fixedly distributed on the base 93. A flexible gasket 91 is provided at the upper ends of the hydraulic support rods 92. The flexible gasket 91 is made of polyurethane and is used to disperse the contact stress, and the flexible gasket 91 abuts against the lower surface of the bridge plate 42.

[0026] The processing unit is used to calculate the angle that the fourth-axis rotating motor 44 needs to adjust the bridge plate 42 based on the levelness data collected by the first digital display dial indicator 54 in real time; calculate the Y-axis deformation span value S of the deformation position of the bridge plate 42 according to the deformation data detected by the rough leveling assembly 55 Y ; detect the X-axis deformation span value S of the deformation position through the second digital display dial indicator 59 X and the Z-axis coordinate Z of the maximum deformation point M ; use the Y-axis deformation span value S of the deformation position of the bridge plate 42 Y and the X-axis deformation span value S X to find the center of the deformation position of the bridge plate 42 and correspond it to the corresponding area of the hydraulic support rods 92, and calculate the compensation amount of the hydraulic support rods 92 for compensation.

[0027] By adopting the above technical solution, when leveling the bridge plate 42, first evenly divide different areas on the base surface (upper surface) of the bridge plate 42 at intervals of 500 mm according to the traditional method. After the division is completed, install the levelness leveling assembly 5 on the tool spindle 6 and start the leveling operation using the levelness leveling assembly 5. Specifically: First, a telescopic rod is provided between the first digital display dial indicator 54 and the Y-axis ball screw drive guide 53. The telescopic rod is used to move downwards, causing the first digital display dial indicator 54 to move downwards until it contacts the base surface of the bridge plate 42 (at this time, the rough leveling assembly 55 does not contact the base surface of the bridge plate 42), and the first digital display dial indicator 54 is zeroed. Then, the control system controls the Y-axis ball screw drive guide 53 to pull the first digital display dial indicator 54 from the initial contact point for a certain distance in the Y-axis direction of the bridge plate 42, records the coordinates of the initial contact point and the final contact point, and uses the processing unit to calculate the angle that the fourth-axis rotation motor 44 needs to adjust the bridge plate 42. Then, the numerical control center system obtains the calculation result of the processing unit and controls the fourth-axis rotation motor 44 to work, driving the bridge plate 42 to rotate to the corresponding angle, so that the flatness error of the base surface of the bridge plate 42 is less than or equal to 0.02 mm, completing the preliminary leveling, and using the telescopic rod to drive the first digital display dial indicator 54 to reset; Then, the Z-axis moving guide 8 is used to move down the tool driving module 7, causing the levelness leveling assembly 5 fixedly connected to the tool driving module 7 to move down, so that the contact ball 556 contacts the base surface of the bridge plate 42. It should be noted that in this application, when there is no external force, the distance between the pressing plate 561 and the pressure sensor 562 is set to 0.02 mm (both of the two springs 560 are in a compressed state without external force and have a large stiffness coefficient, so that the 0.02 mm distance is stably maintained). The Z-axis moving guide 8 is continuously used to drive the levelness leveling assembly 5 to move down, so that the pressing plate 561 contacts and presses the pressure sensor 562. After the pressure sensor 562 detects a pressure signal, the downward movement stops. Then, the control system controls the Y-axis moving guide 3 to drive the bridge plate 42 to move in the Y-axis direction, so that the contact balls 556 of several groups of rough leveling assemblies 55 are pulled along the Y-axis direction on the base surface of the bridge plate 42. If there is a deformed position on the base surface of the bridge plate 42 due to gravity, when the contact ball 556 of the rough leveling assembly 55 passes through the deformed position (the deformation depth is greater than or equal to 0.02 mm), since several rough leveling assemblies 55 are arranged in one-to-one correspondence with the areas evenly divided by the 500 mm interval on the base surface of the bridge plate 42 in the X direction, and the rough leveling assembly 55 is arranged at the middle position of the 500 mm interval area, at this time, the contact ball 556 in the deformed area is no longer pressed by the bridge plate 42, and under the action of the elastic potential energy of the spring 560, the contact ball 556 will move downwards, driving the pressing plate 561 to move down to the unloaded state through the ejector rod 557, and the pressure sensor 562 is not pressed, and the pressure signal disappears; when the contact ball 556 moves out of the deformed position, the pressure sensor 562 is pressed again and a pressure signal appears. According to the disappearance time of the pressure signal and the speed of the Y-axis moving guide 3 driving the levelness leveling assembly 5, the Y-axis deformation span value S of the deformed position is calculated Y, then, the Y-axis moving guide rail 3 drives the fourth-axis assembly 4 to move, so that the second digital display dial indicator 59 on the levelness leveling assembly 5 moves to the middle position of the Y-axis deformation span at the deformation position. The control system controls the X-axis ball screw drive guide rail 58 to drive the second digital display dial indicator 59 to move along the X-axis (the second digital display dial indicator 59 is also connected to the X-axis ball screw drive guide rail 58 through a telescopic rod, and the telescopic rod is used to move downwards so that the second digital display dial indicator 59 starts to contact the base surface of the bridge plate 42, and the first point where the second digital display dial indicator 59 starts to contact the base surface of the bridge plate 42 is set as zero and cleared. At this time, the rough leveling assembly 55 does not contact the base surface of the bridge plate 42). As the second digital display dial indicator 59 moves, the X-axis deformation span value S of the deformation position is detected. X and the Z-axis coordinate Z of the maximum deformation point M , using the Y-axis deformation span value S of the deformation position of the bridge plate 42 Y and the X-axis deformation span value S X find the center of the deformation position of the bridge plate 42 and correspond it to the corresponding area of the hydraulic support rod 92, calculate the upward compensation amount of the hydraulic support rod 92 for compensation, so that the overall flatness error of the base surface of the bridge plate 42 is less than 0.02 mm, and complete the leveling of the flatness of the base surface of the bridge plate 42.

[0028] In some embodiments, the levelness data collected by the first digital display dial indicator 54 in real time is used to calculate the angle that the fourth-axis rotating motor 44 needs to adjust the bridge plate 42. By adopting the above technical solution, the first digital display dial indicator 54 pulls a certain distance in the Y-axis direction of the bridge plate 42. Let the spatial coordinates of the first contact point be X 0 , Y 1 , Z 1 , and the spatial coordinates of the last contact point are X 0 , Y 2 , Z 2 . It should be noted that the spatial coordinates can be obtained by simple calculation by combining the machining center coordinate system with the displacement distance of the first digital display dial indicator 54, and the numerical control system can directly output the relevant coordinates accordingly; the displacement distance of the first digital display dial indicator 54 can be directly obtained from the distance that the system controls the Y-axis ball screw drive guide rail 53 to move, and the calculation formula is established: where θ is the inclination angle between the bridge plate 42 and the central rotating shaft. The rotation angle of the axis of the bridge plate 42 is obtained by using the above calculation formula, and the fourth-axis rotating motor 44 is controlled by the numerical control system of the numerical control center to rotate by the corresponding angle, so that the flatness error of the base surface of the bridge plate 42 is kept less than 0.02 mm.

[0029] In some embodiments, according to the deformation data detected by the rough leveling assembly 55, the Y-axis deformation span value S of the deformation position of the bridge plate 42 is calculated. Y, move all the rough leveling components 55 axially in the Y-axis direction of the cross slide 42. If the horizontal reference plane of the cross slide 42 after preliminary leveling undergoes deformation caused by gravity, the pressure signal of the pressure sensor 562 will disappear during the movement of the rough leveling components 55. Calculate the Y-axis deformation span value S based on the disappearance time and the moving speed of the rough leveling components 55 Y .

[0030] By adopting the above technical solution, set the longest time for the pressure signal of the pressure sensor 562 to disappear as T 1 , and the speed of the Y-axis moving guide 3 driving the levelness leveling component 5 is V 1 , and establish the calculation formula: Obtain the Y-axis deformation span value S of the deformation position according to the above formula Y .

[0031] In some embodiments, detect the X-axis deformation span value S of the deformation position and the Z-axis coordinate Z of the maximum deformation point through the second digital display dial indicator 59 X and the Z-axis coordinate Z of the maximum deformation point M , use the X-axis ball screw drive guide 58 to move the second digital display dial indicator 59 along the X-axis direction in the middle direction of the Y-axis deformation span at the deformation position, and obtain the X-axis deformation span value S of the deformation position X and the Z-axis coordinate Z of the maximum deformation point M .

[0032] By adopting the above technical solution, set the time from the deformation reading detected by the second digital display dial indicator 59 to the disappearance of the deformation reading as T 2 , and the speed of the X-axis ball screw drive guide 58 driving the second digital display dial indicator 59 to move along the X-axis is V 2 , and establish the calculation formula: Obtain the X-axis deformation span value S of the deformation position according to the above formula X .

[0033] It should be noted that signal transceiver modules are provided inside the second digital display dial indicator 59, the first digital display dial indicator 54, and the pressure sensor 562, and signal transceiver can be carried out between them and the numerical control system and the processing unit

[0034] In some embodiments, use the Y-axis deformation span value S of the deformation position of the cross slide 42 Y and the X-axis deformation span value S X to find the center of the deformation position of the cross slide 42 and correspond it to the corresponding area of the hydraulic support rod 92, calculate the compensation amount of the hydraulic support rod 92 and perform compensation, and the processing unit obtains the Y-axis deformation span value S of the deformation position Y and the X-axis deformation span value SX Calculate the center of the deformation position of the bridge plate 42, corresponding to the hydraulic support rod 92 in the corresponding area, calculate the compensation amount of the Z-axis hydraulic support rod 92 required for the deformation position and perform compensation.

[0035] By adopting the above technical solution, from the numerical value S of the deformation span of the Y-axis at the deformation position Y and the numerical value S of the deformation span in the X-axis direction X , take 1 / 2 of each span, and the intersection point is approximately used as the center point of the deformation position. The X-axis and Y-axis coordinates of the corresponding center point are set as X C , Y C . It can be obtained through simple calculation by the numerical control system coordinate system in combination with the numerical value S of the deformation span of the Y-axis at the deformation position Y and the numerical value S of the deformation span in the X-axis direction X . After the calculation by the numerical control system, it will not be elaborated here. After determining the coordinates of the center point of the deformation position, correspond to the hydraulic support rod 92 closest to this coordinate. Here, it should be noted that several hydraulic support rods 92 are arranged at intervals of 500 mm, corresponding to the areas evenly divided by the bridge plate 42 base surface at intervals of 500 mm. And because the deformation of the bridge plate 42 caused by gravity mainly occurs at the mid-span position of the bridge plate 42, the hydraulic support assembly 9 is arranged along the mid-span position; At the same time, obtain the Z-axis coordinate Z of the maximum deformation point M , Z M can be taken as the maximum value detected by the second digital display dial indicator 59 in the deformation area, and establish the calculation formula: Among them, ∆H is the compensation amount that the hydraulic support rod 92 needs to provide for the deformation position of the bridge plate 42, K is the correction coefficient, taking 0.65 - 0.75. In addition, E is the elastic modulus and I is the moment of inertia of the cross-section, both of which can be obtained from relevant experiments. According to the above formula, the compensation amount that the hydraulic support rod 92 closest to the deformation center position needs to provide for the deformation position of the bridge plate 42 is obtained, and the hydraulic support rod 92 is driven to perform compensation, so that the deformation position is adjusted, ensuring the leveling effect and further improving the processing accuracy.

[0036] 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 four-axis unit CNC machining center, comprising a CNC center body (1), wherein a Y-axis movable guide rail (3) is provided on a bottom platform of the CNC center body (1), and an X-axis movable guide rail (2) is fixedly provided on the Y-axis movable guide rail (3); a Z-axis movable guide rail (8) is fixedly connected to one side of the CNC center body (1), and the CNC center body (1) is movably connected to a tool drive module (7) via the Z-axis movable guide rail (8), and a lower end of the tool drive module (7) is fixedly connected to a tool spindle (6); Features: The fourth axis assembly (4) is fixedly connected to the X-axis movable guide rail (2), and the lower end of the tool spindle (6) is detachably connected to a horizontal leveling assembly (5) for leveling the fourth axis assembly (4); The horizontal leveling assembly (5) comprises a main connecting rod (52) and a processing unit, and the main connecting rod (52) is provided with a connecting portion (51) and is detachably connected to a tool spindle (6) through the connecting portion (51), and the connecting portion (51) and the tool spindle (6) can be connected by a threaded connection or a hydraulic clamping connection; the bottom of the main connecting rod (52) is fixedly connected to a fixed base plate (57), one side of the bottom of the fixed base plate (57) is provided with an X-axis ball screw drive guide rail (58), and the bottom of the X-axis ball screw drive guide rail (58) is fixedly connected to a second digital display dial indicator (59), and the other side of the bottom of the fixed base plate (57) is evenly distributed and fixedly connected to a plurality of rough leveling assemblies (55), the left end of the fixed base plate (57) is provided with a Y-axis ball screw drive guide rail (53), and the bottom of the Y-axis ball screw drive guide rail (53) is fixedly connected to a first digital display dial indicator (54), and a battery pack (56) is also provided on the front side of the fixed base plate (57).

2. The four-axis unit CNC machining center according to claim 1, characterized in that: The rough leveling assembly (55) comprises a column (551) fixedly connected to the bottom of a fixed base plate (57); the bottom of the column (551) is fixedly connected to a cylinder (552); two groups of limit plates (553) are symmetrically fixedly connected to the middle position inside the cylinder (552); two groups of springs (560) are symmetrically fixedly installed on opposite sides of the two groups of limit plates (553); a movable plate (554) is fixedly connected to the middle position of the two groups of springs (560); and the movable plate (554) is fixedly connected to the cylinder ( The movable plate (554) is slidably connected to the inner wall of the cylinder (552); the middle position of the movable plate (554) is fixedly connected to a push rod (557); the upper and lower ends of the push rod (557) respectively penetrate two sets of limit plates (553) and are slidably connected to the limit plates (553); the top end of the push rod (557) is fixedly connected to an extrusion plate (561), and the inner top surface of the cylinder (552) is fixedly connected to a pressure sensor (562); the bottom end of the push rod (557) extends to the outside of the cylinder (552) and is fixedly connected to a contact ball (556).

3. The four-axis unit CNC machining center according to claim 2, characterized in that: The fourth axis assembly (4) comprises a tailstock (41) and a fixed seat (43) fixedly connected to the X-axis movable guide rail (2); a bridge plate (42) is rotatably connected between the tailstock (41) and the fixed seat (43); and a fourth axis rotating motor (44) is provided on one side of the tailstock (41) for driving the bridge plate (42) to rotate.

4. The four-axis unit CNC machining center according to claim 3 is characterized in that: A hydraulic support assembly (9) is also fixedly connected to the middle position of the bridge plate (42) on the upper surface of the X-axis movable guide rail (2), and the hydraulic support assembly (9) comprises a base (93) fixedly connected to the upper surface of the X-axis movable guide rail (2), and a plurality of hydraulic support rods (92) are evenly and fixedly distributed on the base (93). The upper ends of the hydraulic support rods (92) are commonly provided with flexible gaskets (91), and the flexible gaskets (91) are made of polyurethane, and the flexible gaskets (91) are pressed against the lower surface of the bridge plate (42).

5. The four-axis unit CNC machining center according to claim 4, characterized in that: The processing unit is used to calculate the angle at which the fourth-axis rotating motor (44) needs to adjust the bridge plate (42) based on the horizontality data collected in real time by the first digital display dial indicator (54); and calculate the Y-axis deformation span value S of the deformation position of the bridge plate (42) based on the deformation data detected by the rough leveling component (55). Y Detect the deformation position X-axis deformation span value S through the second digital display dial indicator (59) X And the Z-axis coordinate of the maximum deformation point Z M ; Using the Y-axis deformation span value S of the bridge plate (42) deformation position Y And the X-axis deformation span value S X The deformation position center of the bridge plate (42) is found and corresponds to the hydraulic support rod (92) in the corresponding area, and the compensation amount of the hydraulic support rod (92) is calculated and compensated.

6. The four-axis unit CNC machining center according to claim 5, characterized in that: The horizontality data collected in real time by the first digital display dial indicator (54) is used to calculate the angle at which the fourth axis rotating motor (44) needs to adjust the bridge plate (42), including: The bridge plate (42) is pulled a certain distance in the Y-axis direction by the first digital display dial indicator (54), and the spatial coordinates of the first contact point are set as X0, Y1, Z1, and the spatial coordinates of the last contact point are set as X0, Y2, Z2. A formula is established to obtain the axis rotation angle of the bridge plate (42), and the fourth axis rotating motor (44) is used to make corresponding adjustments.

7. The four-axis unit CNC machining center according to claim 5, characterized in that: Based on the deformation data detected by the rough leveling assembly (55), the Y-axis deformation span value S of the deformation position of the bridge plate (42) is calculated. Y ,include: All the rough leveling components (55) are moved in the Y-axis direction of the bridge plate (42). If the horizontal reference surface of the bridge plate (42) after preliminary leveling is deformed due to gravity, the pressure signal of the pressure sensor (562) of the rough leveling component (55) will disappear during the movement. The Y-axis deformation span value S is calculated based on the disappearance time and the moving speed of the rough leveling component (55). Y .

8. The four-axis unit CNC machining center according to claim 5, characterized in that: The deformation position X-axis deformation span value S is detected by a second digital display dial gauge (59). X And the Z-axis coordinate of the maximum deformation point Z M ,include: The second digital display dial indicator (59) is moved along the X-axis direction at the center of the Y-axis direction at the deformation point by using the X-axis ball screw to drive the guide rail (58) to obtain the X-axis deformation span value S at the deformation point. X And the Z-axis coordinate of the maximum deformation point Z M .

9. The four-axis unit CNC machining center according to claim 5, characterized in that: The Y-axis deformation span value S of the deformation position of the bridge plate (42) is used. Y And the X-axis deformation span value S X Finding the deformation position center of the bridge plate (42) and corresponding to the hydraulic support rod (92) in the corresponding area, calculating the compensation amount of the hydraulic support rod (92) and performing compensation, including: The processing unit obtains the deformation span value S of the Y axis deformation position Y And the X-axis deformation span value S X , calculate the deformation position center of the bridge plate (42), correspond to the hydraulic support rod (92) in the corresponding area, calculate the compensation amount of the Z-axis hydraulic support rod (92) required for the deformation position and perform compensation.

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