Numerical control milling machine with vibration absorption cross beam structure

Abstract

The invention relates to the technical field of numerical control milling machines, and discloses a numerical control milling machine with a vibration absorption cross beam structure, which comprises a cross beam, the inside of the cross beam is hollow, an upper partition plate, a lower partition plate and an inclined partition plate are arranged in the cross beam, the upper partition plate and the upper end area in the cross beam define an upper cavity, and a first vibration absorption module is arranged in the upper cavity; a middle cavity is defined by the top of the lower partition plate and the bottom area of the upper partition plate, and a second vibration absorption module is arranged in the middle cavity. The inclined partition plate divides the area below the lower partition plate into a lower cavity and a rear wedge-shaped cavity. The interior of the cross beam is divided into the upper cavity, the middle cavity, the lower cavity and the rear wedge-shaped cavity, targeted vibration absorption and energy consumption modules are arranged, all kinds of vibration frequencies generated in the machining process are fully covered, the energy consumption efficiency is improved, and the machining quality is improved. And the influence of vibration on machining is reduced from the source.

Description

Technical Field

[0001] This invention relates to the field of CNC milling machine technology, specifically to a CNC milling machine with a vibration-absorbing crossbeam structure. Background Technology

[0002] A CNC milling machine is a machine tool that uses a computer numerical control (CNC) system to automate machining processes. It controls the relative movement of the cutting tool and the workpiece through pre-programmed instructions to complete machining operations such as milling, drilling, and tapping of complex contours. A CNC milling machine typically consists of core components such as the bed, worktable, column, crossbeam, and spindle box. Among these, the crossbeam, as a key load-bearing structure supporting the spindle box, directly affects machining accuracy and surface quality.

[0003] In large CNC milling machines, with the increase in machining speed and cutting force, the problem of crossbeam vibration is becoming increasingly prominent. Due to the change in the position of the spindle box on the crossbeam and the periodic excitation of the cutting force, the crossbeam will generate bending and torsional vibrations. This vibration will cause relative displacement between the tool and the workpiece, resulting in problems such as surface chatter marks and out-of-tolerance dimensional accuracy, and in severe cases, it may even lead to tool damage.

[0004] Therefore, we propose a CNC milling machine with a vibration-absorbing crossbeam structure. Summary of the Invention

[0005] The purpose of this invention is to provide a CNC milling machine with a vibration-absorbing beam structure, thereby solving or at least alleviating one or more of the above-mentioned problems and other problems existing in the prior art.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a CNC milling machine with a vibration-absorbing crossbeam structure, comprising a bed, a worktable, a column, a crossbeam, and a spindle box. The worktable is mounted on the bed via a Z-axis linear module. The column is fixedly mounted on the bed. The crossbeam is fixedly mounted on the top of the column. An X-axis linear module is mounted on the crossbeam. A Y-axis linear module is mounted on the slide of the X-axis linear module. The spindle box is fixedly mounted on the slide of the Y-axis linear module. The interior of the crossbeam is hollow, and an upper partition, a lower partition, and an inclined partition are fixedly installed inside the crossbeam from top to bottom. The upper partition and the upper inner region of the crossbeam form an upper cavity, and a first vibration-absorbing module for suppressing high-frequency vibration is provided in the upper cavity. The top of the lower partition and the bottom area of ​​the upper partition form a central cavity, and a second vibration-absorbing module for adaptively suppressing the dominant low-frequency vibration is provided in the central cavity; The inclined partition is located below the lower partition. The upper end of the inclined partition is fixedly connected to the side plate of the crossbeam near the spindle box, and the lower end of the inclined partition is fixedly connected to the side plate of the crossbeam away from the spindle box. The inclined partition divides the area below the lower partition into a lower chamber and a rear wedge-shaped chamber; A first energy-consuming module is installed in the rear wedge-shaped cavity, and a second energy-consuming module is installed inside the lower cavity.

[0007] In a CNC milling machine with a vibration-absorbing beam structure according to the present invention, optionally, a plurality of vertical auxiliary partitions are fixedly connected in the upper cavity along the length direction of the beam, and the plurality of vertical auxiliary partitions divide the upper cavity into a plurality of upper unit cavities. Each of the upper unit cavities is provided with a first vibration absorption module; The first vibration absorption module includes a first mass block, and each of the six sides of the first mass block is fixedly connected to a first elastic support block. The end of the first elastic support block away from the first mass block is fixedly connected to the inner wall of the upper unit cavity, thereby suspending the first mass block inside the upper unit cavity.

[0008] In a CNC milling machine with a vibration-absorbing crossbeam structure according to the present invention, optionally, the distribution density of the vertical auxiliary partition decreases gradually from the middle of the crossbeam to both ends; The mass of the first mass block decreases gradually from the middle of the crossbeam to both ends.

[0009] In a CNC milling machine with a vibration-absorbing beam structure according to the present invention, the second vibration-absorbing module may optionally include a plurality of dynamic mass adjustment units, wherein the plurality of dynamic mass adjustment units are equidistantly distributed along the length direction of the beam, and there is an overlapping area between adjacent dynamic mass adjustment units.

[0010] In a CNC milling machine with a vibration-absorbing beam structure according to the present invention, optionally, the dynamic mass adjustment unit includes a guide slide rail, the guide slide rail is fixedly connected to the top of the lower partition, a guide slider is slidably mounted on the guide slide rail, a second elastic support block is fixedly mounted on the guide slider, and a second mass block is fixedly connected to the top of the second elastic support block.

[0011] In a CNC milling machine with a vibration-absorbing beam structure according to the present invention, optionally, the mass of the second mass block located in the middle is greater than the mass of the second mass blocks located at both ends along the length direction of the beam.

[0012] In a CNC milling machine with a vibration-absorbing beam structure according to the present invention, optionally, both ends of the guide rail are fixedly installed with limit bolts by threads.

[0013] In a CNC milling machine with a vibration-absorbing beam structure according to the present invention, optionally, the first energy-consuming module includes a porous elastic damping filling layer, wherein the filling volume of the porous elastic damping filling layer accounts for 70%-80% of the volume of the rear wedge-shaped chamber.

[0014] In a CNC milling machine with a vibration-absorbing beam structure according to the present invention, optionally, the second energy-consuming module includes a damping agent particle filling layer, the damping agent particle filling layer being filled with damping agent particles of various particle sizes, the particle size range of the damping agent particles being 1-5 mm, and the filling volume of the damping agent particle filling layer accounting for 60%-70% of the volume of the lower chamber.

[0015] In a CNC milling machine with a vibration-absorbing beam structure according to the present invention, the porous elastic damping filling layer is optionally one of pre-cured metal rubber or open-cell foam metal module.

[0016] Compared with the prior art, the beneficial effects of the present invention are: This invention divides the interior of the crossbeam into an upper chamber, a middle chamber, a lower chamber, and a rear wedge-shaped chamber, and configures targeted vibration absorption and energy dissipation modules in each chamber. High-frequency vibrations are effectively canceled out by the distributed first vibration absorption module in the upper chamber, the dominant low-frequency vibrations are precisely suppressed by the adaptive second vibration absorption module in the middle chamber, and residual broadband vibrations are dissipated through the two energy dissipation modules. This comprehensively covers all types of vibration frequencies generated during the processing, reducing the impact of vibration on the processing from the source.

[0017] The dynamic mass adjustment unit in the middle chamber adopts an equidistant distribution and overlapping area design. With the sliding cooperation of the guide slider and the guide rail, it can automatically adjust the vibration absorption position according to the position change of the spindle box. This ensures that the spindle box can respond to vibration and play a vibration suppression role in a timely manner when machining in any area of ​​the crossbeam, avoiding the occurrence of vibration absorption blind spots and adapting to the vibration change requirements of dynamic machining scenarios.

[0018] The vertical auxiliary partition and the first mass block of the upper chamber, and the second mass block of the middle chamber, all adopt a gradient distribution design with dense / heavy in the middle and sparse / lightweight at both ends. This concentrates the stronger vibration absorption capacity in the middle of the crossbeam where the vibration is most intense. While maximizing the vibration suppression effect, it reduces the mass redundancy of the overall crossbeam structure, takes into account both structural strength and lightweight requirements, and reduces the energy consumption of the equipment.

[0019] The porous elastic damping filling layer of the rear wedge-shaped chamber is made of pre-cured metal rubber or open-cell foam metal, which has the characteristics of oil resistance, temperature difference resistance and wear resistance, and can maintain stable energy dissipation performance for a long time in the harsh processing environment of machine tools. The damping agent particle filling layer of the lower chamber adopts a multi-particle size mixed design to ensure efficient dissipation of residual vibrations of different frequencies and improve the reliability of long-term operation of the equipment.

[0020] The upper, lower, and inclined partitions inside the crossbeam not only divide the chambers but also act as reinforcing ribs, effectively improving the overall rigidity and torsional resistance of the crossbeam and reducing its own vibration deformation. Through multi-module collaboration, vibration is suppressed in all directions, significantly reducing the relative displacement between the tool and the workpiece, avoiding surface vibration marks and dimensional inaccuracies, and improving the machining quality and product qualification rate of the CNC milling machine. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the structure of a CNC milling machine with a vibration-absorbing crossbeam structure according to the present invention; Figure 2 This is a schematic diagram of the transverse cross-sectional structure of the crossbeam in a CNC milling machine with a vibration-absorbing crossbeam structure according to the present invention. Figure 3 This is a schematic diagram of the longitudinal cross-sectional structure of a CNC milling machine with a vibration-absorbing beam structure according to the present invention when no vertical auxiliary partition is installed; Figure 4 This is a schematic diagram of the longitudinal cross-sectional structure of a CNC milling machine with a vibration-absorbing beam structure according to the present invention; Figure 5 This is a schematic diagram of the structure of the first mass block in a CNC milling machine with a vibration-absorbing crossbeam structure according to the present invention; Figure 6 This is a schematic diagram of the structure of the second vibration-absorbing module in a CNC milling machine with a vibration-absorbing beam structure according to the present invention.

[0022] In the diagram: 1. Bed; 2. Worktable; 3. Column; 4. Crossbeam; 41. Upper partition; 42. Inclined partition; 43. Upper chamber; 431. Vertical auxiliary partition; 432. First vibration absorption module; 4321. First mass block; 4322. First elastic support block; 44. Middle chamber; 45. Lower chamber; 451. Damping agent particle filling layer; 46. Rear wedge-shaped chamber; 461. Porous elastic damping filling layer; 47. Lower partition; 471. Second vibration absorption module; 4711. Guide slide rail; 4712. Guide slider; 4713. Second elastic support block; 4714. Second mass block; 4715. Limiting bolt; 5. Spindle box. Detailed Implementation

[0023] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0024] The accompanying drawings are for illustrative purposes only and are schematic diagrams, not actual images. They should not be construed as limiting the scope of this patent. To better illustrate the embodiments of the present invention, some parts in the drawings may be omitted, enlarged, or reduced, and do not represent the actual dimensions of the product. It is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings.

[0025] In the accompanying drawings of the embodiments of the present invention, the same or similar reference numerals correspond to the same or similar components. In the description of the present invention, it should be understood that if terms such as "upper," "lower," "left," "right," "inner," and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, they are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the terms used to describe positional relationships in the drawings are only for illustrative purposes and should not be construed as limiting the present patent. For those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.

[0026] In the description of this invention, unless otherwise explicitly specified and limited, the term "connection" or similar designation indicating a connection between components should be interpreted broadly. For example, it can refer to a fixed connection, a detachable connection, or an integral part; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can refer to the internal communication between two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0027] Please see Figures 1 to 6 This embodiment provides a CNC milling machine with a vibration-absorbing crossbeam structure, including a bed 1, a worktable 2, a column 3, a crossbeam 4, and a spindle box 5. The worktable 2 is mounted on the bed 1 via a Z-axis linear module. The column 3 is fixedly mounted on the bed 1. The crossbeam 4 is fixedly mounted on the top of the column 3. An X-axis linear module is mounted on the crossbeam 4. A Y-axis linear module is mounted on the slide of the X-axis linear module. The spindle box 5 is fixedly mounted on the slide of the Y-axis linear module. The interior of the crossbeam 4 is hollow, and from top to bottom, the upper partition 41, the lower partition 47 and the inclined partition 42 are fixedly installed inside the crossbeam 4. The upper partition 41 and the upper inner region of the crossbeam 4 form an upper chamber 43, and a first vibration-absorbing module 432 for suppressing high-frequency vibration is provided in the upper chamber 43. The top of the lower partition 47 and the bottom area of ​​the upper partition 41 form a middle cavity 44, and a second vibration absorption module 471 for adaptively suppressing the dominant low-frequency vibration is provided in the middle cavity 44. The inclined partition 42 is located below the lower partition 47. The upper end of the inclined partition 42 is fixedly connected to the side plate of the crossbeam 4 near the main spindle box 5, and the lower end of the inclined partition 42 is fixedly connected to the side plate of the crossbeam 4 away from the main spindle box 5. The inclined partition 42 divides the area below the lower partition 47 into a lower chamber 45 and a rear wedge-shaped chamber 46; A first energy-consuming module is installed in the rear wedge-shaped chamber 46, and a second energy-consuming module is installed inside the lower chamber 45.

[0028] By adopting the above technical solution, when the worktable 2 moves on the bed 1 via the Z-axis linear module and the spindle box 5 moves on the crossbeam 4 via the X-axis and Y-axis linear modules and performs cutting operations, the resulting vibrations are transmitted to the crossbeam 4 sequentially through each linear module and the column 3. The upper chamber 43, middle chamber 44, lower chamber 45, and rear wedge-shaped chamber 46, which are divided by the upper partition 41, lower partition 47, and inclined partition 42, work together: the first vibration absorption module 432 in the upper chamber 43 specifically suppresses high-frequency vibrations, the second vibration absorption module 471 in the middle chamber 44 adaptively cancels the dominant low-frequency vibrations, and the first energy dissipation module in the rear wedge-shaped chamber 46 and the second energy dissipation module in the lower chamber 45 further weaken broadband vibrations through energy dissipation; at the same time, the upper partition 41, lower partition 47, and inclined partition 42 enhance the structural rigidity of the crossbeam 4 and reduce its own vibration deformation, thereby achieving all-round, multi-frequency suppression of the overall vibration of the CNC milling machine.

[0029] Specifically, in this embodiment, a number of vertical auxiliary partitions 431 are fixedly connected in the upper chamber 43 along the length of the crossbeam 4, and the number of vertical auxiliary partitions 431 divide the upper chamber 43 into a number of upper unit chambers. Each upper unit cavity is equipped with a first vibration absorption module 432; The first vibration absorption module 432 includes a first mass block 4321. Each of the six sides of the first mass block 4321 is fixedly connected to a first elastic support block 4322. The end of the first elastic support block 4322 away from the first mass block 4321 is fixedly connected to the inner wall of the upper unit cavity, thereby suspending the first mass block 4321 inside the upper unit cavity.

[0030] By adopting the above technical solution, several vertical auxiliary partitions 431 in the upper chamber 43 divide the upper chamber 43 into multiple independent upper unit cavities. The first vibration absorption module 432 in each upper unit cavity is suspended from the inner wall of the upper unit cavity by the first elastic support block 4322 connected to the first mass block 4321 on six sides, forming multiple distributed "mass-spring" vibration absorption systems. When the crossbeam 4 generates high-frequency vibration, it will drive the first mass block 4321 in each upper unit cavity to generate inertial motion opposite to the vibration direction. The first elastic support block 4322 undergoes elastic deformation and transmits reaction force. Through the mutual cancellation of inertial force and vibration force, the high-frequency vibration of different parts of the crossbeam 4 is accurately suppressed. The six-sided elastic support design ensures that the first mass block 4321 can play a vibration absorption role in multiple directions in space, avoiding the transmission of high-frequency vibration in any dimension.

[0031] Specifically, in this embodiment, the distribution density of the vertical auxiliary partition 431 decreases gradually from the middle of the crossbeam 4 to both ends, and the mass of the first mass block 4321 decreases gradually from the middle of the crossbeam 4 to both ends.

[0032] By adopting the above technical solution and considering the mechanical characteristics of the crossbeam 4, where the amplitude is greatest in the middle and gradually decreases towards both ends during vibration, the vertical auxiliary partitions 431 in the upper chamber 43 are designed with dense distribution in the middle and sparse distribution at both ends. This results in a greater number of upper unit cavities in the middle, and the mass of the first mass block 4321 in the upper unit cavities in the middle is greater than the mass of the first mass block 4321 in the upper unit cavities at both ends. This gradient distribution design concentrates more and stronger vibration absorption resources in the middle of the crossbeam 4 where the vibration is most intense. By increasing the density and mass of the vibration absorption units in the middle, the high-frequency suppression effect on the core vibration area is enhanced. The use of low-density partitions and lightweight first mass blocks 4321 at both ends reduces the overall weight of the crossbeam 4 while ensuring the vibration absorption effect, thus avoiding structural redundancy.

[0033] In this embodiment, the second vibration absorption module 471 includes several dynamic mass adjustment units, which are equidistantly distributed along the length of the crossbeam 4, and there is an overlapping area between adjacent dynamic mass adjustment units.

[0034] By adopting the above technical solution, several dynamic mass adjustment units in the middle chamber 44 are arranged at equal intervals along the length of the crossbeam 4, and overlapping areas are set between adjacent units. When the spindle box 5 moves along the X-axis linear module on the crossbeam 4 and generates cutting-dominant low-frequency vibration, the overlapping area design ensures that no matter where the spindle box 5 is located on the crossbeam 4, there is always at least one dynamic mass adjustment unit below it that can respond to the vibration excitation in a timely manner, avoiding the vibration absorption "blind zone" caused by the movement of the spindle box 5; the equidistant distribution design ensures that the vibration energy can be evenly distributed and suppressed throughout the entire length of the crossbeam 4, achieving comprehensive coverage of dynamically changing low-frequency vibration.

[0035] In this embodiment, the dynamic mass adjustment unit includes a guide slide rail 4711, which is fixedly connected to the top of the lower partition 47. A guide slider 4712 is slidably mounted on the guide slide rail 4711, and a second elastic support block 4713 is fixedly mounted on the guide slider 4712. A second mass block 4714 is fixedly connected to the top of the second elastic support block 4713.

[0036] By adopting the above technical solution, the guide rail 4711 in the dynamic mass adjustment unit provides a sliding track for the guide slider 4712. The guide slider 4712 drives the second mass block 4714 through the second elastic support block 4713 to form a movable "mass-spring" system. When a certain area of ​​the crossbeam 4 generates low-frequency vibration due to cutting by the spindle box 5, the vibration energy of that area will be transmitted to the guide slider 4712, pushing the guide slider 4712 to slide along the guide rail 4711 to the antinode of the vibration wave (the position of maximum amplitude). At this time, the second mass block 4714 generates reverse vibration under the action of the second elastic support block 4713, and the vibration energy is offset by inertial force, realizing adaptive and precise suppression of low-frequency vibration.

[0037] In this embodiment, along the length of the beam 4, the mass of the second mass block 4714 located in the middle is greater than the mass of the second mass blocks 4714 located at both ends.

[0038] By adopting the above technical solution, based on the vibration characteristics that the vibration intensity in the middle of the crossbeam 4 is significantly greater than that at both ends, multiple second mass blocks 4714 arranged along the length of the crossbeam 4 are distributed in a gradient manner with a larger mass in the middle and a smaller mass at both ends. The heavier second mass block 4714 in the middle can generate a larger inertial force, effectively balancing and offsetting the strong low-frequency vibration energy in the middle; while the lighter second mass blocks 4714 at both ends meet the vibration suppression requirements at the ends, avoiding an increase in the overall load of the crossbeam 4 due to excessive mass, thus achieving an optimized balance between vibration suppression effect and structural lightweighting.

[0039] In this embodiment, both ends of the guide rail 4711 are fixedly installed with limit bolts 4715 by threads.

[0040] By adopting the above technical solution, the limiting bolts 4715 threaded at both ends of the guide rail 4711 can be adjusted by rotation to limit the sliding stroke of the guide slider 4712 along the guide rail 4711. During normal operation of the CNC milling machine, the limiting bolts 4715 effectively prevent the guide slider 4712 from impacting the end of the guide rail 4711 due to severe vibration or sudden working conditions, thus preventing the guide slider 4712 from detaching from the guide rail 4711. Simultaneously, the operator can flexibly adjust the position of the limiting bolts 4715 according to the vibration range of the actual machining conditions, optimizing the effective working range of the guide slider 4712 and improving the reliability and adaptability of the vibration absorption system.

[0041] In this embodiment, the first energy-consuming module includes a porous elastic damping filling layer 461, the volume of which accounts for 70%-80% of the volume of the rear wedge-shaped chamber 46.

[0042] By adopting the above technical solution, the porous elastic damping filling layer 461 filling the rear wedge-shaped cavity 46 fills the cavity with a volume ratio of 70%-80%. When the crossbeam 4 vibrates, the vibration energy is transferred to the porous elastic damping filling layer 461, causing its internal pore structure to be squeezed, deformed, and rubbed, converting the mechanical energy of the vibration into heat energy and dissipating it, thereby achieving the dissipation of vibration energy. The 70%-80% filling rate not only ensures sufficient contact between the porous elastic damping filling layer 461 and the inner wall of the rear wedge-shaped cavity 46, ensuring the effective transfer of vibration energy, but also reserves sufficient space for the elastic deformation of the material, avoiding the decrease in damping effect due to overfilling, and achieving efficient energy dissipation and suppression of broadband vibration.

[0043] In this embodiment, the second energy-consuming module includes a damping agent particle filling layer 451, which is filled with damping agent particles of various particle sizes. The particle size range of the damping agent particles is 1-5 mm, and the filling volume of the damping agent particle filling layer 451 accounts for 60%-70% of the volume of the lower chamber 45.

[0044] By adopting the above technical solution, the damping agent particle filling layer 451 in the lower chamber 45 is filled with damping agent particles of mixed sizes from 1 to 5 mm at a volume ratio of 60% to 70%. When the crossbeam 4 vibrates, the particles in the damping agent particle filling layer 451 will collide and rub against each other. At the same time, the particles will also have inelastic collisions with the inner wall of the lower chamber 45. Through collision and friction, the mechanical energy of vibration is converted into heat energy for dissipation. The mixed particle size design increases the contact area and motion complexity between particles, enabling it to adapt to vibrations in a wider frequency range. The 60% to 70% filling rate ensures that the particles have enough space to move and generate effective collisions, but are not too loose, which would reduce energy dissipation efficiency, thus achieving efficient damping and suppression of multi-frequency vibrations.

[0045] In this embodiment, the porous elastic damping filling layer 461 is either a pre-cured metal rubber or an open-cell foam metal module.

[0046] By adopting the above technical solution, the porous elastic damping filling layer 461 is set as a pre-cured metal rubber or open-cell foam metal module. The pre-cured metal rubber has good elasticity, wear resistance, and high temperature resistance, while the open-cell foam metal has the characteristics of being lightweight and having high porosity. Both materials can maintain stable performance under harsh working conditions such as oil stains and temperature differences generated by machine tool cutting. When the crossbeam 4 vibrates, the module dissipates energy through the extrusion deformation of the internal pores and the friction of the ribs. At the same time, the pre-cured structure ensures that it will not collapse due to long-term vibration, ensuring the long-term stable vibration absorption effect of the first energy dissipation module and adapting to the long-term continuous operation requirements of CNC milling machines.

[0047] Specifically, in this embodiment, the calculation equation for the vibration absorption frequency matching value of the dynamic mass adjustment unit of the second vibration absorption module 471 is as follows: ; in: f adaptive The target vibration absorption frequency (Hz) of the dynamic mass adjustment unit must be consistent with the dominant low-frequency vibration frequency of the crossbeam 4 in the current processing scenario. The value range is 2-15Hz, which is determined by equation calculation and actual measurement and calibration of vibration sensor. k eq The equivalent stiffness (N / m) of the second elastic support block 471 reflects its ability to resist deformation. It is calculated using the superposition principle based on the material's elastic modulus, cross-sectional dimensions, and quantity, and its value ranges from 5 × 10⁻⁶. 4 −2×10 5 N / m; m spindle The total mass (kg) of the spindle box 5 includes the mass of the spindle, cutting tools and slide assembly, and the value ranges from 500 to 1200 kg. m beam The net mass (kg) of beam 4, excluding the mass of each vibration absorption and energy dissipation module, is between 2000-5000 kg. m adjust The actual mass (kg) of the second mass block 4714 is distributed in a gradient along the length of the crossbeam 4, with a larger mass in the middle and smaller mass at both ends, and the value ranges from 30 to 80 kg. L spindle The distance (m) between the central axis of the spindle box 5 and one end of the crossbeam 4, ranging from 0 to L. beam ; L beam The total length (m) of beam 4 is 3-6m. α is the mass influence coefficient, with a value ranging from 0.32 to 0.45, which is calibrated by the connection stiffness test between the spindle box 5 and the crossbeam 4; β is the position influence coefficient, with a value ranging from 0.18 to 0.25, which is determined by the bending stiffness distribution characteristics of beam 4.

[0048] I. The derivation process of the equation is as follows: 1. Basic Model Construction: During CNC milling, the crossbeam 4 and the spindle box 5 constitute a "beam-lumen mass" vibration system. The dominant low-frequency vibration is caused by the periodic excitation of the cutting force, and its natural frequency needs to be precisely matched with the absorption frequency of the second vibration absorption module 471. According to classical vibration theory, the natural frequency formula of a single-degree-of-freedom "mass-spring" system is: ; Where k is the spring stiffness and m is the mass of the mass block. However, this formula does not consider the influence of the additional mass and position of the spindle box 5 on the vibration characteristics of the crossbeam 4, and needs further correction.

[0049] 2. Additional quality correction (introducing the α coefficient) The spindle box 5 is connected to the crossbeam 4 via a Y-axis linear module, and its mass changes the equivalent vibrating mass of the crossbeam 4. Let the mass of the spindle box 5 be m. spindle The net mass of beam 4 is m. beam Modal tests revealed that the effect of the added mass on the vibration stiffness of beam 4 is linear. Introducing a mass influence coefficient α, the equivalent stiffness is then corrected as follows: ; The value of α was calibrated through modal tests on multiple sets of spindle boxes with different masses. When the mass of the spindle box is 1 / 5 to 1 / 3 of the mass of the crossbeam, α is stable in the range of 0.32 to 0.45.

[0050] 3. Location effect correction (introducing the β coefficient) The vibration amplitude of the crossbeam 4 is unevenly distributed along its length, and the position L of the spindle box 5 is also uneven. spindle This will change the equivalent vibration mass distribution of beam 4. According to the bending vibration theory of beams, the equivalent mass at any position of beam 4 is linearly related to the distance from that position to the end. Introducing the position influence coefficient β, the equivalent mass of the second mass block 4714 is corrected as follows: ; The value of β was determined by static bending test of beam 4. When the beam is a rectangular structure with uniform cross section, the value of β is 0.18-0.25.

[0051] 4. Final Equation Integration Substituting the corrected equivalent stiffness and equivalent mass into the foundation's natural frequency formula, we obtain the target vibration absorption frequency equation for the dynamic mass adjustment unit, namely: .

[0052] II. Example: 1. Known parameters The second elastic support block 4713: made of polyurethane elastomer, 4 in number, with a single stiffness k1 = 2.5 × 10⁻⁶. 4 N / m, equivalent stiffness k eq =4×2.5×10 4 =1×10 5 N / m; Total mass of spindle box 5 m spindle =800kg; 4m net mass of crossbeam beam =3000kg; The total length of the crossbeam 4 is L beam =4m, current position of spindle box 5 L spindle =2m (middle of the beam); The second mass block in the middle has a mass of 4714 m. adjust =50kg; The experiment calibrated α=0.4 and β=0.2.

[0053] 2. The calculation process is as follows: (1) Calculate the quality correction term: ; (2) Calculate the position correction term: ; (3) Substitute into the equation to calculate the target absorption frequency: 1. Substitute the known parameters: the equivalent stiffness k of the second elastic support block eq =1×10 5 N / m, mass correction term ≈1.1067, the mass of the second mass block is m adjust =50kg, position correction item ; 2. Calculate the numerator: 1 × 10 5 ×1.1067=1.1067×10 5 ; 3. Calculate the denominator: 50 × 1.1 = 55; 4. Calculate the value inside the square root sign: ; 5. Calculate the square root: ; 6. Calculate the target absorption frequency: Hz.

[0054] 3. Application Effects: At this point, adjusting the position of the second mass block 4714 to stabilize its vibration absorption frequency at 7.1Hz can reduce the dominant low-frequency vibration amplitude in the middle of the crossbeam 4 from 0.12mm to below 0.02mm, meeting the requirements of high-precision milling.

[0055] III. Technical Effects 1. Breaking through the limitations of traditional vibration absorption Traditional mass-spring vibration absorption modules use a fixed frequency design, which cannot adapt to the vibration frequency changes caused by the movement of the spindle box. However, this equation introduces α (mass influence) and β (position influence) coefficients to achieve dynamic correction of the vibration absorption frequency, which greatly improves the frequency matching accuracy of the second vibration absorption module.

[0056] 2. Improve low-frequency vibration suppression efficiency By accurately calculating the target vibration absorption frequency using equations, the amplitude suppression rate of low-frequency vibration dominated by the crossbeam can be increased from 50%-60% in traditional solutions to over 85%, avoiding surface texture caused by vibration (texture depth reduced from 15μm to below 3μm) and dimensional inaccuracies (dimensional error reduced from ±0.05mm to ±0.01mm).

[0057] 3. Simplify the debugging process Traditional vibration absorption modules require repeated trial and error to adjust the position and mass of the mass block, with a debugging cycle of up to 2-3 days. Based on this equation, the target value can be calculated directly from the processing parameters (mast and position of the spindle box), shortening the debugging time to 2-4 hours and greatly improving the efficiency of equipment installation and debugging.

[0058] IV. Working Principle and Flowchart 1. Parameter Acquisition Phase (1) When the equipment starts, the system automatically reads the net mass m of the crossbeam 4. beam Total length L beam The equivalent stiffness k of the second elastic support block eq Fixed parameters (pre-stored in the CNC system database); (2) Obtain the current position L of the spindle box 5 through the X-axis linear module position sensor. spindle The total mass m of the spindle box is obtained through a mass sensor. spindle (Including knives); (3) Call the pre-calibrated α and β coefficients (matching the beam structure and spindle box model).

[0059] 2. Frequency Calculation Stage (1) The CNC system substitutes the collected parameters into the equation. Calculate the target vibration absorption frequency in the current scene in real time; (2) The current dominant low-frequency vibration frequency of the crossbeam 4 is measured by the vibration sensor and compared with the calculated value. If the error exceeds ±0.2Hz, the α or β coefficient is automatically corrected (fine adjustment amplitude ≤5%) until the calculated value is consistent with the measured value.

[0060] 3. Dynamic Adjustment Stage (1) Based on the target absorption frequency f adaptive The system controls the guide slider 4712 to slide along the guide rail 4711 to adjust the position of the second mass block 4714 (sliding speed 0.5m / s, positioning accuracy ±0.1mm). (2) After the position adjustment is completed, the deformation force of the second elastic support block 4713 is detected by the pressure sensor to verify the equivalent stiffness k. eq If the stiffness changes by more than ±3%, the spare elastic support block will be automatically replaced to check for stability. (3) Continuously monitor the vibration frequency of the crossbeam. When the spindle box 5 moves (L... spindle Changes) or tool replacements (m spindle When the frequency changes, repeat the above process to achieve real-time dynamic matching of the vibration absorption frequency.

[0061] 4. Stable working phase After the target vibration absorption frequency is matched, the second vibration absorption module 471 counteracts the low-frequency vibration dominated by the crossbeam through the reverse inertial force of the "mass-spring" system. At the same time, it works with the first energy dissipation module of the rear wedge-shaped chamber 46 and the second energy dissipation module of the lower chamber 45 to dissipate residual vibration energy, ensuring that the vibration amplitude of the crossbeam is stable below 0.02mm during the processing, thus meeting the requirements of high-precision processing.

[0062] Working principle: When the spindle box 5 starts machining with the cutting tool, the cutting force will cause multiple vibrations: on the one hand, the high-speed rotation and cutting action of the spindle box 5 itself will generate vibrations, which will be transmitted to the crossbeam 4 through the Y-axis linear module and the X-axis linear module; on the other hand, the worktable 2 will also generate vibrations due to the cutting reaction force during the machining process, which will be indirectly transmitted to the crossbeam 4 through the Z-axis linear module, the bed 1 and the column 3. These vibrations include high-frequency vibrations such as those caused by the high-speed rotation of the tool and dominant low-frequency vibrations such as those caused by the periodic changes in the cutting force. If they are not suppressed, they will affect the machining accuracy and surface quality.

[0063] The first vibration-absorbing module 432 within the upper chamber 43 of the crossbeam 4 immediately responds to high-frequency vibrations. The upper chamber 43 is divided into multiple upper unit chambers by several vertical auxiliary partitions 431. Each upper unit chamber contains a first mass block 4321 suspended by six-sided first elastic support blocks 4322, forming a distributed "mass-spring" system. When high-frequency vibrations are transmitted to this area, the first mass block 4321 generates inertial motion opposite to the vibration direction under vibration excitation. The first elastic support blocks 4322 undergo elastic deformation and generate a reaction force. Through the mutual cancellation of inertial force and high-frequency vibration force, precise suppression of high-frequency vibrations at different parts of the crossbeam 4 is achieved. Simultaneously, because both the vertical auxiliary partitions 431 and the first mass blocks 4321 adopt a gradient distribution design with dense / heavy sections in the middle and sparse / lightweight sections at both ends, they can concentrate on exerting a stronger vibration-absorbing effect in the middle of the crossbeam 4 where vibrations are most intense, ensuring the targeted and efficient suppression of high-frequency vibrations.

[0064] To address the dominant low-frequency vibrations during the cutting process, the second vibration-absorbing module 471 within the central chamber 44 initiates adaptive adjustment. The second vibration-absorbing module 471 consists of several dynamically adjusted mass units equidistantly distributed along the length of the crossbeam 4 with overlapping areas. The guide slider 4712 of each unit slides along the guide rail 4711, driving the movement of the second mass block 4714 connected via the second elastic support block 4713. When the spindle box 5 moves on the crossbeam 4, causing changes in the low-frequency vibration region, the overlapping area design ensures that a corresponding dynamically adjusted mass unit always responds to the vibration region. The guide slider 4712 automatically slides to the antinode of the vibration wave (the point of maximum amplitude), causing the second mass block 4714 to generate a reverse inertial force, precisely counteracting the low-frequency vibration energy. Furthermore, the gradient design, with the mass of the second mass block 4714 in the middle being greater than that at both ends, further enhances the suppression effect on the core vibration region.

[0065] It should be noted that, in this embodiment, the first elastic support block 4322 and the second elastic support block 4713 can be made of one of the following: rubber-based composite material, polyurethane elastomer, and elastic ceramic material.

[0066] After being processed by the high-frequency and low-frequency vibration absorption modules, the remaining broadband vibration energy is transferred to the rear wedge-shaped chamber 46 and the lower chamber 45 below the crossbeam 4, where it is finally dissipated by the first and second energy dissipation modules. Under vibration, the porous elastic damping filling layer 461 in the rear wedge-shaped chamber 46 undergoes compression, deformation, and friction within its internal pore structure, converting the vibrational mechanical energy into heat energy. Its 70%-80% filling rate ensures energy transfer efficiency and material deformation space. The damping agent particle filling layer 451 in the lower chamber 45 further dissipates the remaining vibration energy through particle collisions, friction, and inelastic collisions between particles and the chamber wall. Its 60%-70% filling rate ensures the effectiveness of particle movement and energy dissipation efficiency.

[0067] All parts not described in this invention are the same as or can be implemented using existing technology. Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A CNC milling machine with a vibration-absorbing crossbeam structure, characterized in that, The machine includes a bed (1), a worktable (2), a column (3), a crossbeam (4), and a spindle box (5). The worktable (2) is mounted on the bed (1) via a Z-axis linear module. The column (3) is fixedly mounted on the bed (1). The crossbeam (4) is fixedly mounted on the top of the column (3). An X-axis linear module is mounted on the crossbeam (4). A Y-axis linear module is mounted on the slide of the X-axis linear module. The spindle box (5) is fixedly mounted on the slide of the Y-axis linear module. The interior of the crossbeam (4) is hollow, and the interior of the crossbeam (4) is fixedly installed with an upper partition (41), a lower partition (47) and an inclined partition (42) from top to bottom. The upper partition (41) and the upper inner region of the crossbeam (4) form an upper chamber (43), and a first vibration-absorbing module (432) for suppressing high-frequency vibration is provided in the upper chamber (43). The top of the lower partition (47) and the bottom area of ​​the upper partition (41) form a middle cavity (44), and a second vibration-absorbing module (471) for adaptively suppressing the dominant low-frequency vibration is provided in the middle cavity (44). The inclined partition (42) is located below the lower partition (47). The upper end of the inclined partition (42) is fixedly connected to the side plate of the crossbeam (4) near the spindle box (5), and the lower end of the inclined partition (42) is fixedly connected to the side plate of the crossbeam (4) away from the spindle box (5). The inclined partition (42) divides the area below the lower partition (47) into a lower chamber (45) and a rear wedge-shaped chamber (46). The rear wedge-shaped chamber (46) is provided with a first energy-consuming module, and the lower chamber (45) is provided with a second energy-consuming module.

2. A CNC milling machine with a vibration-absorbing beam structure according to claim 1, characterized in that: Several vertical auxiliary partitions (431) are fixedly connected in the upper chamber (43) along the length of the crossbeam (4), and the several vertical auxiliary partitions (431) divide the upper chamber (43) into several upper unit chambers. Each of the upper unit cavities is provided with a first vibration absorption module (432); The first vibration absorption module (432) includes a first mass block (4321), and each of the six sides of the first mass block (4321) is fixedly connected to a first elastic support block (4322). The end of the first elastic support block (4322) away from the first mass block (4321) is fixedly connected to the inner wall of the upper unit cavity, thereby suspending the first mass block (4321) inside the upper unit cavity.

3. A CNC milling machine with a vibration-absorbing beam structure according to claim 2, characterized in that: The distribution density of the vertical auxiliary partition (431) decreases gradually from the middle of the crossbeam (4) to both ends; The mass of the first mass block (4321) decreases in a gradient from the middle of the crossbeam (4) to both ends.

4. A CNC milling machine with a vibration-absorbing beam structure according to claim 1, characterized in that: The second vibration absorption module (471) includes several dynamic mass adjustment units, which are equidistantly distributed along the length of the crossbeam (4), and there is an overlapping area between two adjacent dynamic mass adjustment units.

5. A CNC milling machine with a vibration-absorbing beam structure according to claim 4, characterized in that: The dynamic mass adjustment unit includes a guide slide rail (4711), which is fixedly connected to the top of the lower partition (47). A guide slider (4712) is slidably mounted on the guide slide rail (4711), and a second elastic support block (4713) is fixedly mounted on the guide slider (4712). A second mass block (4714) is fixedly connected to the top of the second elastic support block (4713).

6. A CNC milling machine with a vibration-absorbing beam structure according to claim 5, characterized in that: Along the length of the beam (4), the mass of the second mass block (4714) located in the middle is greater than the mass of the second mass blocks (4714) located at both ends.

7. A CNC milling machine with a vibration-absorbing beam structure according to claim 5, characterized in that: Both ends of the guide rail (4711) are fixedly installed with limit bolts (4715) by threads.

8. A CNC milling machine with a vibration-absorbing crossbeam structure according to claim 1, characterized in that: The first energy-consuming module includes a porous elastic damping filling layer (461), the volume of which accounts for 70%-80% of the volume of the rear wedge-shaped chamber (46).

9. A CNC milling machine with a vibration-absorbing beam structure according to claim 1, characterized in that: The second energy-consuming module includes a damping agent particle filling layer (451), which is filled with damping agent particles of various particle sizes. The particle size range of the damping agent particles is 1-5 mm, and the filling volume of the damping agent particle filling layer (451) accounts for 60%-70% of the volume of the lower chamber (45).

10. A CNC milling machine with a vibration-absorbing beam structure according to claim 8, characterized in that: The porous elastic damping filling layer (461) is one of pre-cured metal rubber or open-cell foam metal module.

Images