A mechanical low-frequency vibration drilling device with variable amplitude and frequency

Abstract

The application discloses a variable-amplitude and variable-frequency mechanical low-frequency vibration drilling device, which comprises an input shaft connected with a machine tool, an output shaft connected with a drill bit, a vibration auxiliary generating device capable of low-frequency vibration, a bearing capable of bearing axial force and a spring device capable of rebounding; the input shaft is connected with the output shaft through spline connection; the vibration auxiliary generating device comprises a plane washer, a sine washer A, a sine washer B, a ball A, a ball B, a retainer A and a retainer B, which ensure the sine washer to be fixed and the retainer with the ball to be connected with the output shaft through spline connection during work; the sine washer A is fixed below the tapered roller bearing through external thread and always remains fixed; the sine washer B can be controlled by whether the amplitude modulation plug is inserted or not, so that the amplitude and frequency can be changed under the same rotating speed. The device has the advantages of reasonable structure, convenient disassembly and reassembly and stable amplitude and frequency conversion.

Description

Technical Field

[0001] This invention relates to a mechanical low-frequency vibration hole-making device with variable amplitude and frequency, belonging to the field of aerospace manufacturing engineering / aircraft assembly. Background Technology

[0002] In the process of drilling holes in difficult-to-machine materials for aircraft assembly, conventional drilling techniques pose a significant challenge due to their high drilling force, high cutting temperature, and difficult chip removal capabilities. To improve the quality and precision of drilling holes in laminated materials, experts and scholars both domestically and internationally have explored the damage mechanism of drilling holes in laminated materials from multiple perspectives, continuously investigating more advanced drilling processes to achieve damage suppression and produce high-quality, high-precision holes.

[0003] Vibratory drilling transforms the continuous cutting process of traditional drilling into a continuous and rhythmic pulsed cutting process under the influence of external human factors. The fundamental difference between vibratory drilling and ordinary drilling lies in the fact that, through this relative motion, the entire machining process of ordinary drilling becomes a dynamic process of regular contact and separation between the tool and the workpiece material. This regular cutting and separation between the tool and the material effectively reduces cutting forces and friction during machining, while also altering the chip morphology to achieve chip breaking, allowing chips to be smoothly discharged from the hole, improving heat dissipation, and preventing damage to the machined hole surface from chips, thus effectively improving hole quality and precision. Currently, some research has been conducted in the field of low-frequency vibratory drilling devices in China. For example, the "Mechanical Adjustable Amplitude Low-Frequency Axial Vibratory Drilling Device" with patent number CN210817521U features an adjustable amplitude design for the low-frequency vibration device. The vibration amplitude can be adjusted by rotating the outer casing, but the vibration frequency cannot be adjusted at the same rotational speed. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to provide a mechanical low-frequency vibration hole-making device with variable amplitude and frequency, which can be directly installed on a machine tool spindle. The rotation of the machine tool spindle drives the device to rotate, while simultaneously performing low-frequency axial vibration.

[0005] The technical solution of the present invention is as follows: A variable amplitude and frequency mechanical low-frequency vibration drilling device includes an input shaft connected to a machine tool, an output shaft connected to a drill bit, a vibration auxiliary generator capable of low-frequency vibration, a bearing capable of withstanding axial force, and a spring device for rebound. The input shaft and output shaft are connected by a spline. The vibration auxiliary generator includes a flat washer, a sine washer A, a sine washer B, ball A, ball B, a cage A, and a cage B. During operation, the sine washer is fixed, and the cage with balls is connected to the output shaft by a spline. The sine washer A is fixed to the outer shell under the tapered roller bearing by an external thread and remains fixed at all times. The sine washer B is controlled by whether an amplitude adjustment pin is inserted, which can achieve changes in amplitude and frequency at the same rotational speed.

[0006] The upper end face is externally connected to the input shaft and internally connected to a tapered roller bearing. Below the tapered roller bearing is a sinusoidal washer A connected to the housing via threads. A cage A with balls A and a flat washer are connected to the output shaft; this is the first-stage vibration auxiliary generator. Below the flat washer is a sinusoidal washer B with four amplitude-adjusting pins, which contact the housing via grooves. The lower end of the sinusoidal washer B contacts the cage B with balls B, and the lower end of the balls B contacts the output shaft. A return spring is fitted onto the lower end of the output shaft, and the lower end of the return spring is connected to a thrust ball bearing. The lower end of the thrust ball bearing contacts the lower end face. The housing is fixed to the upper and lower end faces with bolts. The assembly clearance of each component is 0.1 mm.

[0007] This invention allows for amplitude adjustment under the same rotational speed. Amplitude adjustment directly affects drilling speed. Increasing the amplitude increases drilling speed, while decreasing the amplitude decreases it. The amplitude can be adjusted reasonably according to actual conditions to control drilling speed and improve drilling efficiency. This invention uses amplitude superposition for frequency modulation, which can be divided into two frequency forms. The first is a single amplitude form. When the amplitude adjustment pin is fixed, the vibration generated in the upper part of the mechanism cannot be transmitted downwards. In this case, the vibration of this invention originates from the sine washer B. That is, when the retainer B drives the ball B to rotate, it vibrates up and down according to the sine curve of the sine washer B. The amplitude generated by this invention in this form is the amplitude of the sine washer B. The second is a complex amplitude form. When the amplitude adjustment pin is pulled out, the sine washer B and the planar washer can engage due to the spring action. At this time, the sine washer A and the sine washer B can function simultaneously. Since the number of cycles of the two is a multiple, the vibrations generated by the two can be superimposed, and the superimposed vibration curve is still a sine curve.

[0008] This invention allows for frequency adjustment under the same rotational speed. Appropriate frequency adjustment can reduce the damaging effects of vibration on the material, decrease fragmentation during drilling, and thus improve drilling quality. This invention employs a phase superposition method, enabling the conversion between two frequencies at the same rotational speed. The first is a single-frequency form. When the amplitude-adjusting pin is fixed, the vibration generated in the upper part of the mechanism cannot be transmitted downwards. In this case, the vibration of this invention originates from the sine washer B. That is, when the cage B drives the ball B to rotate, it vibrates up and down according to the sinusoidal surface of the sine washer B. The frequency generated in this form is determined by the phase of the sine washer B. The second type is the complex frequency form. When the amplitude modulation pin is pulled out, the sine washer B and the flat washer can engage due to the action of the spring. At this time, the sine washer A and the sine washer B can work simultaneously. Since the number of cycles of the two are multiples of each other, the phases generated by the sine washer A and the sine washer B can be superimposed during rotation. The superposition of phases leads to frequency change. The frequency generated by this invention in this form is determined by the phases of the sine washer A and the sine washer B.

[0009] When the sinusoidal washer B is fixed, the vibration generated in the upper part of the mechanism cannot be transmitted downwards. In this case, the vibration of the present invention originates from the sinusoidal washer B. With the sinusoidal washer B fixed, when the cage B drives the ball B to rotate, it vibrates up and down according to the sinusoidal surface of the washer B. Due to the action and reaction forces of the spring, the ball B is in tight contact with the output shaft, driving the output shaft to vibrate during the up-and-down vibration. The collet and nut cooperate, with one end firmly connected to the output shaft and the other end used to clamp the tool. When the output shaft vibrates, it drives the tool to vibrate as well.

[0010] When the sinusoidal washer B is in motion, both the upper and lower parts of the mechanism can vibrate. Due to the spring, the sinusoidal washer B and the flat washer can engage. When the cage A drives the ball A to rotate, it will contact the sinusoidal washer A and generate vibration. When the cage B drives the ball B to rotate, it will contact the sinusoidal washer B and generate vibration. Since the sinusoidal washer B and the flat washer are combined by the force of the spring, their vibrations will be superimposed. At this time, the sinusoidal washer A and the sinusoidal washer B can function simultaneously. The collet and nut are engaged, with one end firmly connected to the output shaft and the other end used to clamp the tool. When the output shaft vibrates, it will drive the tool to vibrate as well.

[0011] The curved surfaces of sinusoidal washers A and B are irregularly shaped sinusoidal surfaces, and both are detachable and replaceable components. The ball bearings A and B have the same structure but different numbers. Cages A and B have M and N through holes, respectively. M ≠ N, and the numbers of M and N are multiples of the period of the sinusoidal washers. The function expression for the sine curve is given by ω, where ω represents the number of periods. The number of periods of sinusoidal washers A and B are multiples of each other. For example, when the number of periods of sinusoidal washer B is 3, the number of holes in cage B should also be 3, and the number of balls B should also be 3. In this case, the number of periods of sinusoidal washer A, the number of holes in cage A, and the number of balls A should all be multiples of 3. Superimposing these components under these conditions still produces a sinusoidal vibration signal.

[0012] The beneficial effects of this invention are: This device can adjust the vibration amplitude and frequency at the same rotational speed, effectively solving problems such as difficulty in removing long chips and affecting machining accuracy. It has the advantages of reasonable structure, easy disassembly and assembly, and stable amplitude and frequency conversion. Frequency adjustment at the same rotational speed can reduce the requirements on the machine tool spindle speed; amplitude adjustment can flexibly control the drilling progress speed as needed. A larger vibration amplitude can increase the friction between the drill bit and the formation, which helps to break the formation and increase the drilling speed; a smaller vibration amplitude can reduce the vibration and damage to the formation, which helps to protect the integrity of the formation. Attached Figure Description

[0013] Figure 1 A schematic diagram of the overall structure of a variable amplitude-frequency mechanical low-frequency vibration hole-making device provided by the present invention; Figure 2 A schematic diagram of the sinusoidal washer A structure of a mechanical low-frequency vibration hole-making device with variable amplitude and frequency provided by the present invention; Figure 3 A schematic diagram of the sinusoidal washer B structure of a mechanical low-frequency vibration hole-making device with variable amplitude and frequency provided by the present invention; Figure 4 This is a schematic diagram of the housing structure of a variable amplitude-frequency mechanical low-frequency vibration hole-making device provided by the present invention.

[0014] In the diagram, 1-input shaft, 2-bolt, 3-upper end face, 4-tapered roller bearing, 5-housing, 6-sine washer A, 7-cage A, 8-flat washer, 9-amplitude adjustment pin, 10-sine washer B, 11-cage B, 12-output shaft, 13-return spring, 14-thrust ball bearing, 15-lower end face, 16-nut, 17-clip, 18-ball B, 19-ball A. Detailed Implementation

[0015] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings. This embodiment is based on the technical solution of the invention and provides detailed implementation methods and specific implementation processes. However, the scope of protection of the present invention is not limited to the following implementation examples.

[0016] The structural and working principles of the present invention will be further explained below with reference to the accompanying drawings. Example

[0017] A variable amplitude and frequency mechanical low-frequency vibration drilling device includes an input shaft connected to a machine tool, an output shaft connected to a drill bit, a vibration auxiliary generator capable of low-frequency vibration, a bearing capable of withstanding axial force, and a spring device for rebound. The input shaft 1 and the output shaft 12 are connected by a spline. The vibration auxiliary generator includes a flat washer 8, a sine washer A6, a sine washer B10, a ball A19, a ball B18, a cage A7, and a cage B11. During operation, the sine washer is fixed, and the cage with the ball is connected to the output shaft by a spline. The sine washer A7 is fixed to the outer shell under the tapered roller bearing by a thread and remains fixed at all times. The inner wall of the outer shell is machined with external threads, and the outer side of the sine washer A10 is machined with threads. The sine washer B10 is controlled by whether an amplitude adjustment pin is inserted, which can achieve changes in amplitude and frequency at the same rotational speed.

[0018] The upper end face 3 is externally connected to the input shaft 1 and internally connected to the tapered roller bearing 4. Below the tapered roller bearing 4 is a sine washer A6 connected to the outer casing 5 via an external thread. Below the sine washer A6 is a cage A7 with balls A19, connected to the output shaft 12 via a spline; this is the first-stage vibration auxiliary generating device. Below the flat washer 8 is a sine washer B10 with four amplitude-adjusting pins 9, contacting the outer casing 5 via a sliding groove. The lower end of the sine washer B10 is connected to the… The ball bearing B18 is in contact with the cage B11, and the lower end of the ball bearing B18 is in contact with the output shaft 12. When axial vibration occurs, the vibration signal can be effectively transmitted to the tool. The lower end of the output shaft 12 is fitted with a return spring 13, and the lower end of the return spring 13 is connected to the thrust ball bearing 14. The lower end of the thrust ball bearing 14 is in contact with the lower end face 15. The end of the lower end face 15 is provided with a collet 17 and a nut 16 for clamping the tool. The outer shell 5 is fixed to the upper end face 3 and the lower end face 15 by bolts 2.

[0019] When the amplitude modulation pin 9 is not inserted, the sine washer A6 is in a fixed state and the sine washer B10 is in a moving state. This is the first amplitude-frequency state. When the amplitude modulation pin is inserted, the sine washer A6 is in a fixed state and the sine washer B10 is in a fixed state. This is the second amplitude-frequency state.

[0020] The sine washers A6 and B10 have irregularly shaped sinusoidal surfaces and are both detachable and replaceable components. The ball bearings A19 and B18 have the same structure but different numbers. The cages A7 and B11 have M and N through holes, respectively. M ≠ N, and the numbers of M and N are multiples of the period of the sine washers. Example

[0021] The overall workflow of this invention is as follows: The input shaft 1 is connected to the machine tool spindle via a pneumatic clamp. The input shaft 1 and the output shaft 12 are connected via a spline. Therefore, while the spindle drives the input shaft 1 to rotate, the output shaft 12 rotates accordingly. In the first working state, when the amplitude adjustment pin 9 is fixed, the vibration generated in the upper part of the mechanism cannot be transmitted downwards. The cage B11 with roller B18 is connected to the output shaft 12 via a spline, so it can rotate with the rotation of the output shaft and can move up and down. At this time, the vibration of this invention originates from the sine washer B10. That is, when the cage B11 drives the roller B18 to rotate, it will vibrate up and down according to the sine surface of the sine washer B10. In the second operating state, when the amplitude adjustment pin 9 is pulled out, the sine washer B10 and the flat washer 8 can engage due to the action of the spring 13. The cage B11 with roller B18 and the cage A7 with roller A19 are connected to the output shaft 12 via splines, so they can rotate with the output shaft and move up and down. At this time, the sine washer A6 and the sine washer B10 can work simultaneously. Since the number of cycles of the two are multiples of each other, the vibrations generated by the two can be superimposed, and the superimposed vibration curve is still a sine curve. The lower end face 15 is provided with a collet 17 and a nut 16. The collet 17 is sleeved on the output shaft 12 and cooperates with the nut 16 to hold the tool.

[0022] This invention utilizes a housing 5, an upper end face 2, and a lower end face 15 to connect the input shaft 1 and the output shaft 12 located at both ends via tapered roller bearings 4, sine washers A6, cages A7 with balls A19, flat washers 8, sine washers B10, cages B11 with balls B18, a return spring 13, and a thrust ball bearing 14. The cages A7 with balls A19 and B11 with balls B18 are connected to the output shaft 12 via splines, employing a clearance fit. This ensures that the output shaft 12 can rotate when the input shaft 1 drives it to rotate; the sine washer A6 is tightened to the outer shell 5 through the external thread to keep it fixed, and the sine washer B10 contacts the outer shell 5 through the sliding groove, so that the outer shell 5 remains fixed when the mechanism moves; when amplitude-frequency conversion is required, four amplitude adjustment pins 9 need to be inserted to fix the sine washer B10. At this time, the axial vibration generated by the sine washer A6 cannot be transmitted, the vibration signal cannot be superimposed, and the frequency and amplitude change successively.

Claims

1. A mechanical low-frequency vibration hole-making device with variable amplitude and frequency, characterized in that, It includes an input shaft connected to the machine tool, an output shaft connected to the drill bit, a vibration auxiliary generator, a bearing that bears axial force, and a spring device for rebound. The input shaft (1) and the output shaft (12) are connected by a spline; the vibration auxiliary generating device includes a flat washer (8), a sine washer A (6), a sine washer B (10), a ball A (19), a ball B (18), a cage A (7), and a cage B (11), which ensures that the sine washer is fixed during operation. The cage with the ball is connected to the output shaft by a spline; the sine washer A (6) is fixed to the outer shell under the tapered roller bearing (4) by an external thread and is always fixed; the sine washer B (10) is controlled by whether or not an amplitude adjustment pin (9) is inserted; The upper end face (3) is externally connected to the input shaft (1) and internally connected to the tapered roller bearing (4); the tapered roller bearing (4) is provided with a sinusoidal washer A (6) connected to the housing by a thread, a cage A (7) with balls A (19) and a flat washer connected to the output shaft (12), which is the first-stage vibration auxiliary generating device; the flat washer (8) is provided with a sinusoidal washer B (10), which is provided with four amplitude adjustment pins (9) and communicates with the housing (5). The sine washer B (10) contacts the cage B (11) with ball B (18) at its lower end, and the lower end of ball B (18) contacts the output shaft (12). The lower end of the output shaft (12) is fitted with a return spring (13), and the lower end of the return spring (13) is connected to a thrust ball bearing (14). The lower end of the thrust ball bearing (14) contacts the lower end face (15), and the outer shell (5) is fixed to the upper end face (3) and the lower end face (15) by bolts (2). The surfaces of the sinusoidal washer A (6) and the sinusoidal washer B (10) are irregular sinusoidal surfaces; the ball A (19) and the ball B (18) have the same structure but different numbers; the cage A (7) and the cage B (11) have M and N through holes respectively; M ≠ N and the number of M and N are multiples of the period of the sinusoidal washer.

2. The variable amplitude-frequency mechanical low-frequency vibration hole-making device as described in claim 1, characterized in that, The aforementioned variable amplitude and frequency mechanical low-frequency vibration drilling device can adjust the amplitude under the same rotation speed, and the adjustment of the amplitude can directly affect the drilling speed.

3. A variable amplitude-frequency mechanical low-frequency vibration hole-making device as described in claim 1 or 2, characterized in that, The variable amplitude mechanical low-frequency vibration hole-making device uses the amplitude superposition method for frequency modulation, which can be divided into two frequency forms. The first is the single amplitude form. When the amplitude adjustment pin (9) is fixed, the vibration generated by the upper part of the mechanism cannot be transmitted downward. At this time, the vibration is generated from the sine washer B (10). That is, when the retainer B (11) drives the ball B (18) to rotate, it will vibrate up and down according to the sine surface of the sine washer B (10). The amplitude generated in this form is the amplitude of the sine washer B (10). The second is the complex amplitude form. When the amplitude adjustment pin (9) is pulled out, due to the action of the spring (13), the sine washer B (10) and the flat washer (8) can be engaged. At this time, the sine washer A (6) and the sine washer B (10) can work at the same time. Since the number of cycles of the two are multiples, the vibration generated by the two can be superimposed. The vibration curve after superposition is still a sine curve.

4. A variable amplitude-frequency mechanical low-frequency vibration hole-making device as described in claim 1 or 2, characterized in that, The number of cycles of the sinusoidal washer A (6) and the sinusoidal washer B (10) are in a multiple relationship.

5. The variable amplitude-frequency mechanical low-frequency vibration hole-making device as described in claim 3, characterized in that, The number of cycles of the sinusoidal washer A (6) and the sinusoidal washer B (10) are in a multiple relationship.

6. A variable amplitude-frequency mechanical low-frequency vibration hole-making device as described in claim 1, 2, or 5, characterized in that, The variable amplitude and frequency mechanical low-frequency vibration hole-making device can adjust the frequency under the same rotation speed. It adopts the phase superposition method and can change two frequencies under the same rotation speed. The first is a single frequency form. When the amplitude adjustment pin (9) is fixed, the vibration generated by the upper part of the mechanism cannot be transmitted downward. At this time, the vibration is generated from the sine washer B (10). That is, when the retainer B (11) drives the ball B (18) to rotate, it will vibrate up and down according to the sine surface of the sine washer B (10). The frequency generated in this form is determined by the phase of the sine washer B (10). The second is a complex frequency form. When the amplitude adjustment pin (9) is pulled out, due to the action of the spring (13), the sine washer B (10) and the flat washer (8) can be engaged. At this time, the sine washer A (6) and the sine washer B (10) can work at the same time.

7. The variable amplitude-frequency mechanical low-frequency vibration hole-making device as described in claim 3, characterized in that, The variable amplitude and frequency mechanical low-frequency vibration hole-making device can adjust the frequency under the same rotation speed. It adopts the phase superposition method and can change two frequencies under the same rotation speed. The first is a single frequency form. When the amplitude adjustment pin (9) is fixed, the vibration generated by the upper part of the mechanism cannot be transmitted downward. At this time, the vibration is generated from the sine washer B (10). That is, when the retainer B (11) drives the ball B (18) to rotate, it will vibrate up and down according to the sine surface of the sine washer B (10). The frequency generated in this form is determined by the phase of the sine washer B (10). The second is a complex frequency form. When the amplitude adjustment pin (9) is pulled out, due to the action of the spring (13), the sine washer B (10) and the flat washer (8) can be engaged. At this time, the sine washer A (6) and the sine washer B (10) can work at the same time.

8. The variable amplitude-frequency mechanical low-frequency vibration hole-making device as described in claim 4, characterized in that, The variable amplitude and frequency mechanical low-frequency vibration hole-making device can adjust the frequency under the same rotation speed. It adopts the phase superposition method and can change two frequencies under the same rotation speed. The first is a single frequency form. When the amplitude adjustment pin (9) is fixed, the vibration generated by the upper part of the mechanism cannot be transmitted downward. At this time, the vibration is generated from the sine washer B (10). That is, when the retainer B (11) drives the ball B (18) to rotate, it will vibrate up and down according to the sine surface of the sine washer B (10). The frequency generated in this form is determined by the phase of the sine washer B (10). The second is a complex frequency form. When the amplitude adjustment pin (9) is pulled out, due to the action of the spring (13), the sine washer B (10) and the flat washer (8) can be engaged. At this time, the sine washer A (6) and the sine washer B (10) can work at the same time.

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