A turning tool clamping mechanism based on composite damping technology

Abstract

A lathe tool clamping mechanism based on composite vibration reduction technology includes a mounting groove in the middle for holding the lathe tool. The upper part of the mounting groove is an upper fixing part, and the lower part is a lower support part. The upper fixing part has multiple threaded holes vertically formed for screws to pass through and clamp the lathe tool. An inverted conical first cavity is located at the center of the upper fixing part, with its bottom not lower than the upper surface of the mounting groove. The surface of the first cavity is covered with damping material. Multiple conical holes are laterally formed on the circumferential side of the upper fixing part, gradually increasing in size from bottom to top. These conical holes are filled with damping material. An annular groove is formed on the bottom surface of the lower support part, with its centerline coinciding with the central axis of the tool clamping mechanism. The width of the annular groove gradually increases from bottom to top. Vibrations from the lathe tool accumulate at the contact point between the tool clamping mechanism and the tool, and are then absorbed and eliminated by the damping material, thus achieving better vibration reduction and extending the service life of the lathe tool.

Description

Technical Field

[0001] This invention relates to the field of machine tool technology, specifically to a cutting tool clamping mechanism based on composite vibration reduction technology. Background Technology

[0002] Vibration and tool chatter during machine tool processing cause chatter marks on the workpiece surface, resulting in high rework and scrap rates. Machine tool vibration is generally caused by insufficient rigidity in one or more of the three systems: machine tool, workpiece, and cutting tool. Tool vibration in lathe machining is caused by tool jumping due to the interaction force between the cutting tool and the material during turning. Traditional methods to reduce tool vibration involve increasing the tool's strength and tightening the fixing nut. However, over-reliance on high-strength cutting tools leads to excessive material waste, greater vibration during feed, and prolonged vibration of the lathe's mounting bracket causing the fixing nut to loosen, resulting in reduced machining accuracy. Summary of the Invention

[0003] To address the aforementioned technical problems, this invention provides a lathe tool clamping mechanism based on composite vibration reduction technology. This mechanism concentrates the vibrations generated by the lathe tool at the contact point between the tool clamping mechanism and the tool, and then absorbs and eliminates the vibrations using damping materials, thereby achieving better vibration reduction and extending the service life of the lathe tool.

[0004] To achieve the above technical objectives, the adopted technical solution is as follows: a lathe tool clamping mechanism based on composite vibration reduction technology. The lathe tool clamping mechanism has a mounting groove in the middle for placing the lathe tool. The upper part of the mounting groove is an upper fixing part, and the lower part is a lower support part. The upper fixing part has multiple threaded holes vertically opened for screws to pass through to clamp the lathe tool. The inner center of the upper fixing part has an inverted conical first cavity. The bottom of the first cavity is not lower than the upper surface of the mounting groove. The surface of the first cavity is covered with damping material. Multiple conical holes are opened laterally inward on the circumferential side of the upper fixing part. The conical holes gradually increase in size from the bottom to the opening. The conical holes are filled with damping material. An annular groove is opened on the bottom surface of the lower support part. The center line of the annular groove coincides with the central axis of the lathe tool clamping mechanism. The width of the annular groove gradually increases from the bottom to the opening.

[0005] The bottoms of two adjacent conical holes with an included angle are connected.

[0006] A honeycomb-shaped damping ring groove is provided on the outer surface of the lower support adjacent to the mounting groove. The honeycomb-shaped damping ring groove is filled with damping material or elastic oscillator.

[0007] A mating cavity is provided on the lower surface of the mounting groove near the root of the central shaft.

[0008] The beneficial effects of this invention are:

[0009] 1. The problem solved by this invention is the vibration transmission problem between the tool clamping mechanism and the lathe as a whole. It ensures the fixation stability and service life of the tool. In terms of improving machining accuracy, it can only reduce the number of vibrations and improve the smoothness of the workpiece surface to a certain extent. The first cavity, tapered hole and annular groove structure are very small in volume, so the damping material filled inside them consumes less material than other structures, but can play a very good role. It reduces the material on the upper surface of the tool clamping mechanism while ensuring its rigidity. The first cavity provides primary vibration reduction, the tapered hole reduces the vibration of the tool clamping mechanism, and the annular groove gathers and consumes the remaining vibration, thereby optimizing machining accuracy and reducing economic losses to a certain extent.

[0010] 2. By connecting the bottoms of adjacent conical holes, the vibrations collected at the connection point can be dissipated quickly.

[0011] 3. Adding a honeycomb damping ring groove can initially absorb the vibration transmitted by the cutting tool, and consume it through internal damping materials or elastic oscillators, reducing the burden of the ring groove on the consumption of other vibrations, resulting in a better vibration reduction effect.

[0012] 4. Increase the mating cavity and reduce the distance between the annular groove and the lower surface of the mounting groove to improve the vibration absorption and damping effect of the annular groove, without affecting the degree of elastic deformation of the tool clamping mechanism. Utilize the space of the mating cavity to fill with damping material to absorb the vibration between the annular groove and the lower surface of the mounting groove. Attached Figure Description

[0013] Figure 1 This is a three-dimensional structural diagram of the present invention;

[0014] Figure 2 This is a partial cross-sectional structural schematic diagram of the present invention;

[0015] Figure 3 This is a schematic diagram of the cross-section of the annular groove and the mating cavity of the present invention;

[0016] Figure 4 This is a cross-sectional view of the tapered hole of the present invention;

[0017] Figure 5 This is a simulation diagram of the present invention;

[0018] In the figure: 1. Lathe tool, 2. Mounting groove, 201. Upper surface of mounting groove, 202. Lower surface of mounting groove, 3. Upper fixing part, 301. Threaded hole, 302. First cavity, 303. Tapered hole, 4. Lower support part, 401. Honeycomb vibration damping groove, 402. Mating cavity, 403. Annular groove. Detailed Implementation

[0019] The preferred embodiments of the invention are given below with reference to the accompanying drawings to illustrate the technical solution of the invention in detail. The corresponding drawings will be provided for detailed explanation of the invention. It should be particularly noted that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit or restrict the invention.

[0020] In the description of this embodiment, the terms "inner," "outer," "front," "rear," "left," and "right," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used merely for the convenience of describing the present invention and for 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, they should not be construed as limitations on the present invention. Furthermore, the terms "first" and "second" are only used to distinguish similar objects and should not be construed as a specific order or sequence. It should be understood that such usage can be interchanged where appropriate.

[0021] like Figure 1 , Figure 3 As shown, a lathe tool clamping mechanism based on composite vibration reduction technology is fixed on a machine tool for mounting and fixing lathe tools. The overall structure is a block shape. The middle part of the lathe tool clamping mechanism is provided with a mounting groove 2 for placing the lathe tool 1. The mounting groove 2 can be designed as a "U" shape, so that the lathe tool 1 can be inserted and fixed from the side regardless of its position. Alternatively, the mounting groove 2 can be designed as a slot to facilitate the alignment of the lathe tool 1 with the workpiece. The thickness of the mounting groove 2 is matched with the thickness of the mounting tail end of the lathe tool 1 to prevent the lathe tool from shaking after installation.

[0022] The upper part of the mounting slot 2 is the upper fixing part 3, and the lower part is the lower support part 4. Figure 2 As shown, the upper fixing part 3 and the lower support part 4 are connected by a central shaft. The outer side of the central shaft is the mounting groove 2. The upper fixing part 3, the lower support part 4, and the central shaft can be integrally formed. The upper fixing part 3 has a plurality of threaded holes 301 vertically opened for screws to pass through to clamp the cutting tool 1. The cutting tool 1 also has threaded holes for connecting with screws.

[0023] like Figure 3 As shown, the upper fixing part 3 has an inverted conical first cavity 302 at its internal center. The bottom of the first cavity 302 is not lower than the upper surface 201 of the mounting groove, which is used to gather primary vibration damping. The surface of the first cavity 302 is covered with damping material to initially absorb the vibration gathered in the first cavity 302. To facilitate the processing of the first cavity 302, the upper fixing part can be divided into upper and lower parts. The upper part is cast separately. Using the corresponding threaded hole, the clamping of the cutting tool 1 and the fastening connection of the upper fixing part can be achieved. The corresponding function of the first cavity 302 is:

[0024] h(x) = -0.0123*x m+60 1.88≤m≤2 (1)

[0025] In formula (1), the cross section of the tool clamping mechanism is a square, and the value of x should be less than or equal to 0.3d, where d is the side length of the tool clamping mechanism.

[0026] like Figure 4 As shown, the upper fixed part 3 has multiple conical holes 303 laterally opened on its circumferential side, i.e., the conical holes 301 are arranged in the circumferential direction of the first cavity 302. The bottom of the conical holes 303 is aligned with the large end of the first cavity 302 to concentrate the vibration after it has been damped by the first cavity 302. The conical holes 303 gradually increase in size from the bottom to the opening, which can concentrate and release the vibration. The conical holes 303 are filled with damping material to consume the concentrated vibration. The damping material used in this application can be butyl rubber. An annular groove 403 is opened on the bottom surface of the lower support part 4. The center line of the annular groove 403 coincides with the central axis of the cutting tool clamping mechanism. The width of the annular groove 403 gradually increases from the bottom to the opening. The annular groove 403 is used as the second cavity.

[0027] h(x) = -0.123*x m +50 1.5≤m≤1.7 (2)

[0028] In formula (2), the cross section of the tool clamping mechanism is square, and the value of x should be 0.3d to 0.45d.

[0029] Due to the limited space available in the tool clamping mechanism in existing technologies, the growth rate of the power function of the first and second cavities varies at different locations, resulting in different amplitude coefficients and powers. Therefore, different placement positions of the damping grooves or cavities lead to different damping levels. This structure also consists of primary and secondary damping. When the cutting tool encounters vibration, the vibration is transmitted through the tool to the tool clamping mechanism, and then each cavity begins to function. Because the inverted conical first cavity concentrates the vibration from the first stage, vibrations that cannot be concentrated will also propagate towards the central cylinder. In the downward transmission process, firstly, when the vibration comes into contact with the first cavity, it is absorbed. Then, the vibration is further dissipated by the first cavity and the conical hole located above it. The first cavity and the conical hole together form an acoustic black hole model with gradually decreasing thickness from the outside to the inside, which has a good vibration concentration effect. The small holes of the conical hole structure absorb the vibration, while the large holes release the vibration. The surface of the first cavity is covered with damping material, which can directly dissipate the vibration. The remaining vibration is concentrated and then absorbed by the damping material located in the conical hole. Finally, the vibration is completely dissipated. The function h(x) = εx followed by the structure of the first cavity is... m+c, different functions are applied to different scenarios. By changing the values ​​of the given parameters, such as: x is different points on the acoustic black hole structure, G(x) represents the thickness of the acoustic black hole at different x points, m is the order of its thickness variation, and ε represents the slope value of each point on the longitudinal section, changing their values ​​can obtain functions applicable to different scenarios.

[0030] During the operation of lathes, milling machines, drilling machines, etc., in factories, vibrations are generated due to the contact between the cutting tool and the workpiece. When the vibration is transmitted, if some of the vibration transmitted from the cutting tool to the tool clamping mechanism can be eliminated, the vibration above the cutting tool will first be collected by the primary damping acoustic black hole (first cavity) cavity model and then eliminated by damping material. If the vibration is too large to be completely eliminated, it will be eliminated by the tapered hole, that is, the secondary acoustic black hole cavity. This can reduce the vibration of the cutting tool. The vibration below the cutting tool will be collected and consumed by the second cavity, which can optimize the machining accuracy and reduce economic losses to a certain extent.

[0031] Furthermore, such as Figure 4 As shown, the bottoms of two adjacent conical holes 303 with an included angle are connected. Vibration is rapidly concentrated through the connection at the bottom, and energy is rapidly dissipated using the connected damping material. If the two conical holes on one side of the figure are arranged parallel to each other, they do not need to be connected at the bottom. The two adjacent conical holes 303 on opposite sides have an included angle, allowing them to connect at the bottom.

[0032] like Figure 2 , Figure 3 As shown, a honeycomb-type damping ring groove 401 is provided on the outer surface of the lower support part 4 adjacent to the mounting groove 2. The honeycomb-type damping ring groove 401 is filled with damping material. The width of the honeycomb-type damping ring groove 401 is basically located above the second cavity. The honeycomb-type damping ring groove initially absorbs the vibration transmitted by the cutting tool after the first-stage damping and can be consumed by the damping material attached to it. Since the overall size of the honeycomb is small, the vibration will continue to be transmitted downward to the second cavity, where it will be absorbed and consumed.

[0033] like Figure 3 As shown, a mating cavity 402 is provided on the lower surface 202 of the mounting groove near the root of the central shaft of the mounting groove 2. The mating cavity 402 is filled with damping material. The mating cavity can further reduce the thickness between the bottom of the second cavity and the lower surface 202 of the mounting groove to improve the vibration reduction effect of the second cavity. The damping material filled in the cavity can eliminate the vibration that cannot be consumed at this location and in the second cavity.

[0034] Figure 5The simulation example shows that the structural model has excellent vibration damping effect at high frequencies and good vibration concentration effect at mid-frequency frequencies. The fluctuation curve is relatively smooth. In the figure, there is no structural comparison and resonance occurs in the 1000 Hz frequency band. The vibration damping structure of the cutting tool clamping damping mechanism of this application has obvious amplitude reduction effect after adding damping, and the vibration damping effect is significantly improved.

[0035] The above are merely preferred embodiments of the present invention and are not intended to limit or restrict the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection declared by the present invention.

Claims

1. A lathe tool clamping mechanism based on composite vibration reduction technology, wherein the lathe tool clamping mechanism has a mounting groove (2) in the middle for placing a lathe tool (1), the upper part of the mounting groove (2) is an upper fixing part (3) and the lower part is a lower support part (4), and the upper fixing part (3) has a plurality of threaded holes (301) vertically opened on it for screws to pass through to clamp the lathe tool (1), characterized in that: The upper fixing part (3) has an inverted conical first cavity (302) at its internal center. The bottom of the first cavity (302) is not lower than the upper surface (201) of the mounting groove. The surface of the first cavity (302) is covered with damping material. The upper fixing part (3) has multiple conical holes (303) laterally opened inward on its circumferential side. The bottoms of two adjacent conical holes (303) with an included angle are connected. The conical holes (303) gradually increase in size from the bottom to the opening. The conical holes (303) are filled with damping material. The bottom of the lower support part (4) An annular groove (403) is provided on the surface. The center line of the annular groove (403) coincides with the central axis of the cutting tool clamping mechanism. The width of the annular groove (403) gradually increases from the bottom to the opening. A honeycomb damping ring groove (401) is provided on the outer surface of the lower support part (4) adjacent to the mounting groove (2). The honeycomb damping ring groove (401) is filled with damping material. A mating cavity (402) is provided on the lower surface (202) of the mounting groove (2) near the root of the central shaft. The mating cavity (402) is filled with damping material.

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