Drilling and boring rod vibration suppression device based on variable stiffness nonlinear energy trap

Abstract

The invention relates to the technical field of drilling and boring rod vibration suppression, in particular to a drilling and boring rod vibration suppression device based on a variable stiffness nonlinear energy trap. In order to solve the problem that vibration suppression of an existing nonlinear energy trap has limitation, the drilling and boring rod vibration suppression device based on the variable-rigidity nonlinear energy trap is provided and comprises a connecting base and a variable-rigidity NES mechanism. An annular groove is formed in the connecting base, the variable-rigidity NES mechanism comprises two tiles, a flexible hinge embedded with a piezoelectric ceramic stack is arranged between the two tiles, and a plurality of bent beams are axially arranged on each tile. The device is reasonable in design, simple in structure and small in occupied space, and a thought and a method are provided for reducing vibration of the deep hole drilling and boring rod and improving the workpiece machining quality.

Description

Technical Field

[0001] This invention relates to the field of drill boring bar vibration suppression technology, specifically a drill boring bar vibration suppression device based on a variable stiffness nonlinear energy trap. Background Technology

[0002] During deep hole machining, when the length-to-diameter ratio of the machined hole is large, the deep hole drill boring bar is prone to chatter, which leads to a significant decrease in the machining quality of the part, and in severe cases, may even cause the part to be scrapped. Therefore, research on mechanical vibration control methods for deep hole drill boring bars is particularly important. As a major factor affecting machining accuracy, tool durability, and cutting efficiency, the main causes of vibration in deep hole drill boring bars include: when drilling deep holes with a large length-to-diameter ratio, the deep hole drill boring bar is relatively slender, equivalent to a cantilever beam, with weak bending stiffness; imbalance between the weight of the tool holder and the cutting forces between the cutting edges; poor stiffness of the power transmission system; and non-uniform workpiece material.

[0003] In the field of deep hole drilling and boring bar vibration suppression technology, nonlinear energy traps (NES) are highly effective in suppressing nonlinear passive vibrations. This passive control technology mainly consists of three parts: a relatively light added mass, strong nonlinear stiffness, and damping elements. The energy transfer mechanism between the NES and the main structure is targeted energy transfer. This transfer is characterized by high speed and unidirectional (irreversible) characteristics. However, in deep hole drilling and boring, the diversity of machining parameters and the continuous feed of the drilling and boring bar's length-to-diameter ratio create dual disturbances from external factors and the system itself. This leads to problems such as difficulty in triggering the nonlinear energy trap's target energy transfer, easy failure of the nonlinear energy trap, and poor vibration suppression efficiency in deep hole machining. Therefore, the vibration suppression of nonlinear energy traps has limitations. Summary of the Invention

[0004] In order to address the limitations of existing nonlinear energy trap vibration suppression devices, this invention provides a drill boring bar vibration suppression device based on a variable stiffness nonlinear energy trap.

[0005] This invention is achieved using the following technical solution:

[0006] A vibration damping device for a drill boring bar based on a variable stiffness nonlinear energy trap includes a cylindrical connecting base for connecting the drill bit and the drill boring bar, and a variable stiffness NES mechanism. The connecting base has an annular groove coaxially located at its axial center. The variable stiffness NES mechanism includes two tiles coaxially fixed to the annular groove and symmetrically distributed about the axis of the connecting base. Each tile has axial protrusions perpendicularly fixed at both circumferential ends, arranged away from the center and along the axial direction. Multiple guide holes are evenly distributed along the length direction on the two axial protrusions at the upper ends of the two tiles, and a circumferential flexible spacing is provided between the two axial protrusions. A flexible hinge embedded with a piezoelectric ceramic stack is positioned within the circumferential flexible spacing, and a circumferential movable spacing is provided between the flexible hinge and the circumferential flexible spacing. Multiple curved beams are evenly distributed axially between the two axial protrusions of each tile. One end of each curved beam is fixed to the corresponding axial protrusion at the lower end of the tile, and the other end of each curved beam slides through the guide hole and is fixed to the corresponding outer surface of the flexible hinge.

[0007] Working principle: In the vibration damping device described in this invention, the mass block is a tile, the bending beam is nonlinear stiffness, and the damping is oil film damping. The variable stiffness NES mechanism adopts a dual-mode stiffness adjustment mechanism of "coarse adjustment + fine adjustment", which realizes the efficient optimization of the vibration damping performance of the NES. In the coarse adjustment stage, when the deep hole drilling and boring rod changes due to changes in processing parameters or boundary conditions such as length-to-diameter ratio, the stiffness of the NES is adjusted to a suitable range by increasing or decreasing the number of bending beams and changing the radius of curvature of the bending beams. In the fine adjustment stage, the deformation of the bending beams is finely adjusted by the piezoelectric ceramic stack, and the most suitable and precise stiffness change is controlled in real time. This allows the nonlinear energy trap to achieve fine dynamic adjustment of the NES stiffness again according to the current processing conditions. This design fundamentally solves the problems of traditional NES being prone to failure due to differences in processing parameters and low vibration suppression efficiency during deep hole drilling and boring. It provides a stable and reliable stiffness adjustment basis for the NES, while ensuring that the NES can maintain excellent performance when the processing conditions change dynamically. It expands the vibration suppression frequency band of the NES, broadens the resonance capture range, increases the vibration energy absorption rate, and can be applied to more processing scenarios. Finally, the absorbed vibration energy is consumed through oil film damping (oil film damping is the oil film generated between the drill hole and the tile during the processing) to achieve the purpose of vibration suppression and improve the quality of deep hole processing.

[0008] Furthermore, each tile has circumferential protrusions fixed vertically at both ends along its axial direction, located away from the center and arranged circumferentially along its length. Each tile achieves an interference fit with the annular groove through two circumferential protrusions. This concretizes and standardizes the tile-annular groove fixing structure.

[0009] Furthermore, the variable stiffness NES mechanism also includes two fixing blocks. Fixing grooves are provided on both side walls corresponding to the annular groove and the circumferential flexible spacing. Horizontally arranged shoulder plates are fixed to the upper ends of the two tiles, with both ends of the shoulder plates extending axially into the fixing grooves. An axial spacing is provided between the axial end faces of the two shoulder plates and the axial side walls of the fixing grooves. Flexible hinges slide circumferentially on the axial center of the two shoulder plates. Both fixing blocks are stepped blocks, and both are interference-fitted into the two fixing grooves and pressed against the two ends of the shoulder plates. The fixing structure of the two tiles and the annular groove is more stable and reliable, preventing vibration from causing the interference fit between the tiles and the annular groove to loosen, thus affecting structural stability.

[0010] Furthermore, the flexible hinge includes a near-square flexible frame and four positioning connection parts located on the outer perimeter of the flexible frame. A piezoelectric ceramic stack is embedded in the near-square flexible frame. The near-square flexible frame consists of two vertical flexible frames arranged circumferentially and two V-shaped flexible frames whose openings face outwards. Positioning grooves for securing the four positioning connection parts are provided on the two fixing blocks and the two axial protrusions at the upper ends of the two tiles. This represents a concretization and standardization of the flexible hinge positioning and fixing structure.

[0011] Furthermore, the flexible hinge also includes two thrust plates, which are arranged side by side on the outside of the two V-shaped flexible frames and fixed to the corresponding two positioning connections. The other ends of the multiple curved beams are abutted against the outer side of the thrust plates (in this application, the outer side refers to the side of two plates facing away from each other, and the inner side refers to the side of two plates facing each other), making the structure more specific and standardized.

[0012] Furthermore, a circumferential assembly gap is provided between the two axial protrusions at the lower ends of the two tiles to avoid assembly failures due to errors during processing or assembly.

[0013] Furthermore, all the tiles are lightweight, achieving a lightweight design for the device.

[0014] Furthermore, one end of the connecting base is provided with an external thread for adapting to the drill boring bar, and the other end of the connecting base is provided with an internal thread for adapting to the drill bit, which facilitates assembly.

[0015] The beneficial effects of this invention are as follows: Based on a variable stiffness nonlinear energy trap, this invention can effectively suppress the energy generated by the vibration of deep hole drilling and boring rods, with a significant vibration suppression effect. The nonlinear stiffness in the variable stiffness nonlinear energy trap can ensure internal resonance with the main structure, achieving excellent vibration suppression capability over a wider frequency band. Simultaneously, due to changes in processing parameters or different length-to-diameter ratios, NES (Non-Electro-Electro-Mechanical Systems) may encounter problems such as difficulty in triggering target energy transfer, easy failure of the nonlinear energy trap, and poor vibration suppression efficiency in deep hole machining. By coarsely adjusting the number of parallel bending beams and the bending curvature, and then finely adjusting the deformation of the bending beams through piezoelectric ceramic stacks, the optimal and precise stiffness change can be controlled in real time, enabling the nonlinear energy trap to transfer and dissipate vibration energy again according to the current processing conditions. This invention is rationally designed, simple in structure, and occupies little space, providing ideas and methods for reducing the vibration of deep hole drilling and boring rods and improving workpiece machining quality. Attached Figure Description

[0016] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0019] Figure 2 This is a schematic diagram of the structure connecting the substrate;

[0020] Figure 3 This is a schematic diagram of a variable stiffness NES mechanism;

[0021] Figure 4 This is a schematic diagram of the tile structure;

[0022] Figure 5 A schematic diagram of a flexible hinge;

[0023] Figure 6 This is a structural schematic diagram of the fastener.

[0024] In the figure: 1-connecting base, 2-annular groove, 3-tile, 4-axial protrusion, 5-guide hole, 6-circumferential flexible spacing, 7-bending beam, 8-flexible hinge, 801-vertical flexible frame, 802-V-shaped flexible frame, 803-positioning connection, 804-thrust plate, 805-piezoelectric ceramic stack, 9-circumferential protrusion, 10-fixing block, 11-fixing groove, 12-tile shoulder, 13-circumferential assembly spacing. Detailed Implementation

[0025] To better understand the above-mentioned objectives, features, and advantages of the present invention, the solutions of the present invention will be further described below. It should be noted that, unless otherwise specified, the embodiments of the present invention and the features thereof can be combined with each other.

[0026] In this description, it should be noted that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. It should also be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joint" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms according to the specific circumstances.

[0027] Many specific details are set forth in the following description in order to provide a full understanding of the invention, but the invention may also be practiced in other ways different from those described herein; obviously, the embodiments in the specification are only some embodiments of the invention, and not all embodiments.

[0028] The specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0029] like Figure 1 , 2As shown in Figure 3, a drill boring bar vibration suppression device based on a variable stiffness nonlinear energy trap includes a cylindrical connecting base 1 for connecting the drill bit and the drill boring bar, and a variable stiffness NES mechanism. The connecting base 1 has an annular groove 2 coaxially located at its axial center. The variable stiffness NES mechanism includes two tiles 3 coaxially fixed to the annular groove 2 and symmetrically distributed about the axis of the connecting base 1. Each tile 3 has two axially protruding strips 4 vertically fixed at both circumferential ends, arranged away from the center and along the axial direction. The two axially protruding strips 4 at the upper ends of the two tiles 3... Multiple guide holes 5 are evenly distributed along the length direction, and a circumferential flexible gap 6 is provided between the two axial protrusions 4. A flexible hinge 8 with a piezoelectric ceramic stack 805 is positioned and arranged in the circumferential flexible gap 6, and a circumferential movable gap is provided between the flexible hinge 8 and the circumferential flexible gap 6. Multiple curved beams 7 are evenly distributed axially between the two axial protrusions 4 of each tile 3. One end of each curved beam 7 is fixed to the axial protrusion 4 at the lower end of the corresponding tile 3, and the other end of each curved beam 7 slides through the guide hole 5 and is fixed to the corresponding outer side of the flexible hinge 8.

[0030] Working principle: In the vibration damping device described in this invention, the mass block is tile 3, the bending beam 7 has nonlinear stiffness, and the damping is oil film damping. The variable stiffness NES mechanism adopts a dual-mode stiffness adjustment mechanism of "coarse adjustment + fine adjustment", which realizes the efficient optimization of the vibration damping performance of the NES. In the coarse adjustment stage, when the deep hole drilling and boring rod changes due to changes in processing parameters or boundary conditions such as length-to-diameter ratio, the stiffness of the NES is adjusted to a suitable range by increasing or decreasing the number of bending beams 7 and changing the radius of curvature of the bending beams 7. In the fine adjustment stage, the deformation of the bending beams 7 is finely adjusted by the piezoelectric ceramic stack 805, and the most suitable and precise stiffness change is controlled in real time. This allows the nonlinear energy trap to achieve fine dynamic adjustment of the NES stiffness again according to the current processing conditions. This design fundamentally solves the problems of traditional NES being prone to failure due to differences in processing parameters and low vibration suppression efficiency during deep hole drilling and boring. It provides a stable and reliable stiffness adjustment basis for the NES, while ensuring that the NES can maintain excellent performance when the processing conditions change dynamically. It expands the vibration suppression frequency band of the NES, broadens the resonance capture range, increases the vibration energy absorption rate, and can be applied to more processing scenarios. Finally, oil film damping is used to consume the absorbed vibration energy through the oil film generated between the borehole and the tile 3 during the processing, thereby achieving the purpose of vibration suppression and improving the quality of deep hole processing.

[0031] In specific implementation, such as Figure 4 As shown, each tile 3 has circumferential protrusions 9 vertically fixed at both ends along its axial direction, located away from the center and arranged circumferentially along its length. Each tile 3 achieves an interference fit with the annular groove 2 through two circumferential protrusions 9. This illustrates the specification and standardization of the fixing structure between the tile 3 and the annular groove 2.

[0032] In specific implementation, such as Figure 6 As shown, the variable stiffness NES mechanism also includes two fixing blocks 10. Fixing grooves 11 are provided on both side walls corresponding to the annular groove 2 and the circumferential flexible spacing 6. Horizontally arranged shoulder 12 is fixed to the upper ends of the two tiles 3, with both axial ends of the shoulder 12 extending axially into the fixing groove 11. An axial distance is provided between the axial end faces of the two shoulder 12 and the axial side walls of the fixing groove 11. A flexible hinge 8 slides circumferentially on the axial middle of the two shoulder 12. Both fixing blocks 10 are stepped blocks, and both fixing blocks 10 are interference-fitted into the two fixing grooves 11 and pressed against the two ends of the two shoulder 12. The fixing structure of the two tiles 3 and the annular groove 2 is more stable and reliable, preventing vibration from causing the interference fit between the tiles 3 and the annular groove 2 to loosen, thus affecting structural stability.

[0033] In specific implementation, such as Figure 5 As shown, the flexible hinge 8 includes a near-square flexible frame and four positioning connection parts 803 located on the outer perimeter of the flexible frame. A piezoelectric ceramic stack 805 is embedded in the near-square flexible frame. The near-square flexible frame consists of two vertical flexible frames 801 arranged circumferentially and two V-shaped flexible frames 802 whose openings face outwards. Positioning grooves for securing the four positioning connection parts 803 are provided on the two fixing blocks 10 and the two axial protrusions 4 at the upper ends of the two tiles 3. This represents a specific and standardized positioning and fixing structure for the flexible hinge 8.

[0034] In specific implementation, the flexible hinge 8 also includes two thrust plates 804. The two thrust plates 804 are arranged side by side on the outside of the two V-shaped flexible frames 802 and fixed to the corresponding two positioning connection parts 803. The other end of the multiple curved beams 7 is abutted against the outer side of the thrust plate 804 (in this application document, the outer side refers to the side of two plates facing away from each other, and the inner side refers to the side of two plates facing each other), making the structure specific and standardized.

[0035] In this specific embodiment, a circumferential assembly spacing shoulder 13 is provided between the two axial protrusions 4 at the lower ends of the two tiles 3 to avoid the inability to assemble due to errors during processing or assembly.

[0036] In this specific embodiment, all tiles 3 are lightweight tiles 3, thus achieving the lightweight design of the device.

[0037] In this specific embodiment, one end of the connecting base 1 is provided with an external thread for adapting to the drill boring bar, and the other end of the connecting base 1 is provided with an internal thread for adapting to the drill bit, which facilitates assembly.

[0038] The above description is merely a specific embodiment of the present invention, enabling those skilled in the art to understand or implement the present invention. Although detailed descriptions have been provided with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments, and they should all be covered within the protection scope of the claims.

Claims

1. A variable stiffness non-linear energy sink based drill boring pole chatter suppression device, characterized by, The application relates to a variable stiffness NES mechanism for connecting a drill bit and a drill rod, which comprises a cylindrical connecting base (1) for connecting the drill bit and the drill rod, the variable stiffness NES mechanism, an annular groove (2) coaxially arranged in the axial middle part of the connecting base (1), the variable stiffness NES mechanism comprising two tiles (3) coaxially fixed on the annular groove (2) and symmetrically distributed about the axis of the connecting base (1), axial protrusions (4) perpendicularly fixed on the circumferential two end parts of each tile (3) and arranged away from the center and in the length direction along the axial direction, a plurality of guide holes (5) uniformly distributed on the two axial protrusions (4) of the upper end parts of the two tiles (3) in the length direction and a circumferential flexible spacing (6) arranged between the two axial protrusions (4), a flexible hinge (8) embedded with a piezoelectric ceramic stack (805) positioned and arranged in the circumferential flexible spacing (6) and a circumferential movable spacing arranged between the flexible hinge (8) and the circumferential flexible spacing (6), a plurality of curved beams (7) arranged in the axial direction between the two axial protrusions (4) of each tile (3), one end of each curved beam (7) being fixed with the axial protrusion (4) of the lower end part of the corresponding tile (3), and the other end of each curved beam (7) being fixed with the corresponding outer side surface of the flexible hinge (8) after sliding through the guide hole (5).

2. The variable stiffness nonlinear energy sink based boring bar chatter suppression device of claim 1, wherein, The circumferential two end parts of each tile (3) are perpendicularly fixed with circumferential protrusions (9) arranged away from the center and in the length direction along the circumferential direction, and each tile (3) is realized by the interference fit of the two circumferential protrusions (9) with the annular groove (2).

3. The variable stiffness nonlinear energy sink based boring-milling bar chatter suppression device of claim 2, wherein, The variable stiffness NES mechanism further comprises two fixed blocks (10), the two side walls of the annular groove (2) corresponding to the circumferential flexible spacing (6) are provided with fixed grooves (11), the upper end parts of the two tiles (3) are fixed with horizontally arranged tile shoulders (12), the axial two end parts of the tile shoulders (12) extend into the fixed grooves (11) in the axial direction, the axial two end surfaces of the two tile shoulders (12) are provided with an axial spacing from the axial side walls of the fixed grooves (11), the flexible hinge (8) is circumferentially and slidingly arranged on the axial middle part of the two tile shoulders (12), the two fixed blocks (10) are step blocks, the two fixed blocks (10) are interference-fitted into the two fixed grooves (11) and are pressed against the two end parts of the two tile shoulders (12).

4. The variable stiffness nonlinear energy sink based boring bar chatter suppression device of claim 3, wherein, The flexible hinge (8) comprises a nearly square flexible frame and four positioning connecting parts (803) respectively arranged on the outer sides of the four circumferential sides of the flexible frame, the piezoelectric ceramic stack (805) is embedded in the nearly square flexible frame, the nearly square flexible frame is composed of two vertically arranged V-shaped flexible frames (802) and two vertically arranged vertical flexible frames (801) with the openings of the two vertical flexible frames (801) arranged on the outer sides, the two fixed blocks (10) and the two axial protrusions (4) of the upper end parts of the two tiles (3) are provided with positioning grooves respectively used for clamping the four positioning connecting parts (803).

5. A variable stiffness nonlinear energy sink based boring bar chatter suppression device according to claim 4, wherein, The flexible hinge (8) further comprises two thrust plates (804), the two thrust plates (804) are arranged side by side on the outer sides of the two V-shaped flexible frames (802) and are fixed with the corresponding two positioning connecting parts (803), and the other ends of the plurality of curved beams (7) are clamped to the outer side surfaces of the thrust plates (804).

6. A variable stiffness nonlinear energy sink based boring bar chatter suppression device according to claim 5, wherein, The circumferential assembly spacing shoulder (13) is arranged between the two axial protrusions (4) of the lower end parts of the two tiles (3).

7. A variable stiffness nonlinear energy sink based boring-milling bar chatter suppression device according to claim 6, characterized in that, All tiles (3) are lightweight tiles (3).

8. The variable stiffness nonlinear energy sink based boring-milling bar chatter suppression device of claim 7, wherein, One end of the connecting base (1) is provided with an external thread for adapting to the drill boring bar, and the other end of the connecting base (1) is provided with an internal thread for adapting to the drill bit.

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