Amplitude-adjustable axial low-frequency vibration auxiliary drilling and drilling device

Abstract

The invention belongs to the technical field of deep hole machining, and particularly relates to an amplitude-adjustable axial low-frequency vibration auxiliary drilling and drilling device which comprises an input shaft, a lower shell, an upper shell and an output shaft which are connected with a machine tool, and the bottom of the input shaft is connected with the output shaft with a first sine curved surface and a second sine curved surface. The output shaft is sleeved with the upper shell and the lower shell from bottom to top, and the upper shell and the lower shell are fixedly connected; a ball bearing is arranged between the upper shell and the input shaft and is in interference fit with the upper shell and the input shaft; the bottom end face of the lower shell and the top end face of the upper shell are each provided with a plurality of grooves in advance, balls are placed in the grooves correspondingly, and the balls roll in the grooves and are tangent to and tightly connected with the first sine curved surface and the second sine curved surface of the output shaft. The problems that long cuttings are difficult to remove and machining precision is affected are effectively solved, and the device has the advantages of being reasonable and simple in structure, convenient to disassemble and assemble and capable of stably changing amplitude.

Description

Technical Field

[0001] The invention belongs to the technical field of deep hole processing, and in particular relates to an amplitude-adjustable axial low-frequency vibration-assisted drilling and hole-making device. Background Art

[0002] In the metalworking industry, deep-hole machining, as a key process step, plays a decisive role in the precision of components used in high-end equipment manufacturing, such as aerospace and automotive manufacturing. With the widespread use of difficult-to-machine materials (such as titanium alloys and nickel-based high-temperature alloys) and the surging demand for small, deep holes with large aspect ratios (aspect ratio ≥ 20:1) in precision machinery, the limitations of traditional drilling processes have become increasingly pronounced. From a mechanical performance perspective, excessive drilling force has become a core bottleneck restricting machining efficiency. During deep-hole drilling, the contact length between the tool and the workpiece increases significantly, leading to a significant increase in axial force and torque. When machining difficult-to-machine materials with a hardness of 45HRC or higher, peak drilling forces can reach 2-3 times that of conventional materials. This not only accelerates tool coating peeling and cutting edge cracking, but also causes workpiece deformation during clamping, resulting in hole diameter roundness errors exceeding the tolerance range of the ISO 286-1 standard. In terms of thermal effects, the temperature in the drilling zone can exceed 800°C under continuous cutting. This high temperature causes carbide tools to soften, reducing their hardness by approximately 30%. It also induces residual thermal stresses on the workpiece surface, causing the hole diameter to shrink or expand, and degrading the surface roughness Ra from an initial 1.6μm to over 6.3μm. Failure of the chip evacuation system is another major risk in deep hole machining. Due to the closed nature of deep hole structures, the flow resistance of chips increases exponentially within the confined space. If chips generated by spiral drilling cannot be promptly evacuated, they can easily form blockages within the hole. When chip accumulation pressure exceeds a critical value, it can cause tool chipping or scratching of the workpiece interior. This is particularly true when machining tiny deep holes with diameters ≤3mm, where the incidence of chip blockage can reach over 40%. The lack of rigidity and increased vibration of the slender drill rod during machining of deep holes with large aspect ratios further exacerbate these issues, increasing hole straightness error by 50% and reducing tool life to one-third of that under conventional conditions. These technical bottlenecks have caused the unit labor cost of deep hole processing to increase by 2-3 times, seriously restricting the production efficiency and economic benefits of the precision manufacturing industry. Summary of the Invention

[0003] In response to the shortcomings of the existing technology, the purpose of the present invention is to provide an axial low-frequency vibration-assisted drilling and hole-making device with adjustable amplitude. The device is provided with an output shaft with a first sinusoidal surface and a second sinusoidal surface. The first sinusoidal surface and the second sinusoidal surface are in contact with the balls in the grooves on the lower shell and the upper shell respectively, thereby realizing low-frequency axial vibration. The device can adjust the vibration amplitude and is easy to operate, effectively solving the problems of long chips being difficult to remove and affecting processing accuracy. It has the advantages of reasonable and simple structure, easy disassembly and assembly, and stable amplitude change.

[0004] An amplitude-adjustable axial low-frequency vibration-assisted drilling and hole-making device comprises an input shaft, a lower housing, an upper housing, and an output shaft connected to a machine tool; an output shaft having a first sinusoidal surface and a second sinusoidal surface is connected to the bottom of the input shaft; the upper housing and the lower housing are sleeved on the output shaft from bottom to top, and the upper housing and the lower housing are fixedly connected; a ball bearing is provided between the upper housing and the input shaft, and the ball bearing has an interference fit with the upper housing and the input shaft; a plurality of grooves are preset on the bottom end face of the lower housing and the top end face of the upper housing, and balls are placed in the grooves respectively. The balls roll in the grooves and remain tangent to and tightly connected to the first and second sinusoidal surfaces of the output shaft.

[0005] The output shaft is connected to an ER32 retaining spring at its lower portion, and the ER32 retaining spring is connected to an ER32 collet nut. The ER32 retaining spring is used to clamp the tool.

[0006] The first sinusoidal curved surface and the second sinusoidal curved surface of the output shaft are identical, the curved surface of the first sinusoidal curved surface faces downward, and the curved surface of the second sinusoidal curved surface faces upward.

[0007] The output shaft is a detachable and replaceable component.

[0008] A spring washer is provided between the bottom of the ball bearing and the upper shell for supporting the ball bearing.

[0009] A stopping device is fixedly connected to the lower shell, and the other end of the stopping device is connected to a brake block of the machine tool.

[0010] The beneficial effects of the present invention are as follows: 1. The present invention applies an axial vibration with controllable frequency and amplitude to the tool during the drilling process, so that regular contact and separation occurs between the tool and the workpiece, thereby effectively reducing the drilling force, reducing the drilling temperature, improving the cutting surface quality, and facilitating chip removal. It is particularly suitable for difficult-to-process materials and small deep hole processing. At the same time, the output shaft of the present application is a replaceable structure. By replacing output shafts of different sizes, the amplitude can be adjusted. Therefore, the present invention can adjust the amplitude under the same rotational speed, optimize the cutting process, and improve processing efficiency and quality. By adjusting the amplitude, the vibration parameters can be matched with the cutting conditions, thereby optimizing the cutting process. Appropriate amplitude adjustment can change the force of the tool on the workpiece surface, making the cutting force more evenly distributed. The amplitude adjustment method of the present invention is convenient and fast and has relatively low assembly requirements.

[0011] 2. The position of the balls of the present invention is limited by the grooves preset in the upper and lower shells, so that the balls can only roll on the track defined by the sinusoidal surface. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 A schematic cross-sectional view of the overall structure of an axial low-frequency vibration-assisted drilling and hole-making device with adjustable amplitude provided by the present invention; Figure 2 A schematic diagram of the output shaft structure of an axial low-frequency vibration-assisted drilling and hole-making device with adjustable amplitude provided by the present invention; Figure 2 (a) Schematic diagram of the first sinusoidal surface of the output shaft of an axial low-frequency vibration-assisted drilling and hole-making device with adjustable amplitude provided by the present invention; Figure 2 (b) is a schematic diagram of the second sinusoidal surface of the output shaft of an axial low-frequency vibration-assisted drilling and hole-making device with adjustable amplitude provided by the present invention; Figure 3 A schematic diagram of the structure of a stopper device of an axial low-frequency vibration-assisted drilling and hole-making device with adjustable amplitude provided by the present invention and a brake block cooperating with a machine tool; In the figure: 1. ER32 retaining spring; 2. ER32 collet nut; 3. Output shaft; 31. First sinusoidal surface; 32. Second sinusoidal surface; 4. Lower housing; 5. Upper housing; 6. Input shaft; 7. Ball bearing; 8. Pin; 9. Ball; 10. Stop device; 11. Fastening bolt; 12. Spring washer; 13. Brake pad. DETAILED DESCRIPTION

[0013] The structural principle and working principle of the present invention will be further described below with reference to the accompanying drawings.

[0014] like Figures 1-3As shown, an amplitude-adjustable axial low-frequency vibration-assisted drilling and hole-making device includes an input shaft 6 connected to a machine tool, a ball 9, an output shaft 3 with a first sinusoidal surface 31 and a second sinusoidal surface 32, a spring washer 12 for rebound, a pin 8 and a fastening bolt 11 for positioning and connection, a stopper 10 for limiting, a lower housing 4 and an upper housing 5, an ER32 retaining ring 1 and an ER32 collet nut 2 for clamping the tool, and all of the above devices move coaxially.

[0015] An amplitude-adjustable axial low-frequency vibration-assisted drilling and hole-making device, wherein the bottom of the input shaft 6 is connected to an output shaft 3 with a first sinusoidal surface 31 and a second sinusoidal surface 32, the input shaft 6 and the output shaft 3 are coaxially arranged, the upper housing 5 and the lower housing 4 are sleeved on the output shaft 3 from bottom to top, and the upper housing 5 and the lower housing 4 are fixedly connected, specifically by fastening bolts 11 to maintain the overall structure; a ball bearing 7 is provided between the upper housing 5 and the input shaft 6, the ball bearing 7 is interference fit with the upper housing 5 and the input shaft 6, and a spring washer 12 is provided between the bottom of the ball bearing 7 and the upper housing 5 for supporting the ball bearing 7; the lower housing The bottom end surface 4 and the top end surface of the upper housing 5 are respectively pre-set with a plurality of grooves. In this embodiment, three grooves are provided, each of which houses a ball 9. The ball 9 rolls in the groove and remains tangential to and closely connected with the first sinusoidal surface 31 and the second sinusoidal surface 32 of the output shaft 3. The output shaft 3 is connected to an ER32 retaining spring 1 at its lower end, which is connected to an ER32 collet nut 2. The ER32 retaining spring 1 is used to clamp the tool. A stopper 10 is fixedly connected to the lower housing 4. The other end of the stopper 10 is connected to a brake block 13 of the machine tool to limit the degree of freedom of rotation in space.

[0016] The first sinusoidal curved surface and the second sinusoidal curved surface of the output shaft are identical, the curved surface of the first sinusoidal curved surface faces downward, and the curved surface of the second sinusoidal curved surface faces upward.

[0017] In this embodiment, all components are kept under permanent pressure. The inner ring of the ball bearing 7 is interference fit with the input shaft 6, and the outer ring is interference fit with the upper shell 5 to transmit rotation. A spring washer 12 is provided under the bearing to provide support. The balls 9 are placed in the preset grooves of the upper shell 5 and the lower shell 4 respectively, and the other surfaces thereof are in contact with the first sinusoidal surface 31 and the second sinusoidal surface 32 of the output shaft 3 respectively. The balls 9 are tangent to the first sinusoidal surface 31 and the second sinusoidal surface 32 and are closely connected. The curved surface of the first sinusoidal surface 31 on the output shaft 3 faces downward, and the curved surface of the second sinusoidal surface 32 faces upward. The first sinusoidal surface 31 and the second sinusoidal surface 32 of the output shaft 3 are the same, including amplitude and period. The balls 9 roll on the two surfaces. The annular grooves of the upper shell 5 and the lower shell 4 are formed. The groove serves to maintain the spacing between the balls 9 and limit their movement; the upper end of the output shaft 3 is connected to the input shaft 6 through a pin 8, and the lower end contacts the ball 9 placed on the lower housing 4 through a first sinusoidal surface 31; the output shaft 3 is connected to the ER32 retaining spring 1, and the ER32 retaining spring 1 is connected to the ER32 collet nut 2; the upper housing 5 is connected to the lower housing 4 by a fastening bolt 11, and is sleeved from bottom to top on the output shaft 3 with the first sinusoidal surface 31 and the second sinusoidal surface 32; the stopping device 10 is welded to the lower housing 4, and the other end is connected to the brake block 13 on the machine tool to limit the rotation of the retaining frame; the bottom end of the input shaft 6 is coaxial with the top end of the output shaft 3 with the first sinusoidal surface 31 and the second sinusoidal surface 32, and is connected through a ball bearing 7 and a spring washer 12.

[0018] The present invention applies an axial vibration with controllable frequency and amplitude to the tool during the drilling process, causing regular contact and separation between the tool and the workpiece, thereby converting traditional continuous drilling into intermittent drilling. This application can effectively reduce drilling force, reduce drilling temperature, improve cutting surface quality, and facilitate chip removal, making it particularly suitable for difficult-to-machine materials and small deep hole machining. Vibration drilling can expand the machining range and is suitable for machining different materials and complex shapes. By adjusting the amplitude, the cutting parameters can be adapted to different machining requirements. This technology can also improve machining accuracy and extend tool life, thereby improving machining efficiency and reducing machining costs.

[0019] The output shaft 3 with the first sinusoidal surface 31 and the second sinusoidal surface 32 are detachable and replaceable components. By replacing the surfaces with different periods and amplitudes, the amplitude and frequency of an adjustable axial low-frequency vibration-assisted drilling and hole-making device can be changed. The function expression of the sine curve is: , A is the amplitude of the sine curve, is the period of the sine curve, is the phase angle of the sine curve; the housing has M preset grooves, M is related to the number of balls, and the number of balls is related to the number of periods of the sine surface In multiple relationship.

[0020] The first sinusoidal surface 31 and the second sinusoidal surface 32 of the output shaft 3 have the same amplitude and period, and a phase difference of π / 3. Frequency modulation and amplitude modulation can be achieved by replacing the output shaft with sinusoidal surfaces of different periods and amplitudes. No adjustment is required, and it can be used immediately after replacement. The amplitude adjustment method is convenient and fast, and the assembly requirements are relatively low. It can be replaced by disassembling the upper shell and the lower shell. At the same time, it solves the problems of the inability to adjust parameters in traditional low-frequency vibration assisted processing equipment, difficulty in use when the workpiece size is too large, and high assembly requirements.

[0021] The present invention can adjust the amplitude while maintaining the same rotational speed, which is significant in optimizing the cutting process and improving processing efficiency and quality. By adjusting the amplitude, the vibration parameters can be matched with the cutting conditions, thereby optimizing the cutting process. Appropriate amplitude adjustment can change the force exerted by the tool on the workpiece surface, making the cutting force more evenly distributed. Vibration is generated by the rolling of balls on a sinusoidal surface, generating axial displacement. In the present invention, the amplitude can be adjusted by replacing the output shaft 3 with the first sinusoidal surface 31 and the second sinusoidal surface 32.

[0022] The overall workflow of the present invention is as follows: The input shaft 6 is connected to the machine tool via a fixture. The rotation of the machine tool drives the input shaft 6, which in turn rotates the ball bearing 7, whose inner ring has an interference fit with the input shaft and whose outer ring has an interference fit with the upper housing 5. This rotation is then transmitted to the upper housing 5. The input shaft 6 is connected to the output shaft 3 via a pin 8, causing the output shaft 3, which has the first and second sinusoidal surfaces 31 and 32, to rotate accordingly. Because all components are maintained under permanent pressure, the output shaft 3, which has the first and second sinusoidal surfaces 31 and 32, the ER32 retaining ring 1, the ER32 collet nut 2, and the tool also rotate accordingly. A stopper 10, one end of which is welded to the lower housing 4 and the other end of which is connected to the machine tool via a brake block 13, restricts the rotation of the lower housing 4 but does not restrict its movement. The balls 9 are placed in the grooves preset in the upper and lower housings 5 and 4, respectively. Their other surfaces are in contact with the first and second sinusoidal surfaces 31 and 32 of the output shaft 3, respectively. The balls 9 remain tangential to and closely connected to the first and second sinusoidal surfaces 31 and 32. When the mechanism rotates, the balls 9 can only roll in the preset grooves. Due to the compression of the upper and lower surfaces, the tool handle vibrates. The first and second sinusoidal surfaces 31 and 32 have the same period, and the vibrations they produce can be superimposed, with the superimposed vibration curve remaining a sinusoidal curve. When adjusting the amplitude, simply replace the output shaft 3 with a sinusoidal surface of different amplitude and period, and the system can be used immediately without the need for positioning, making it quick and convenient.

[0023] The present invention utilizes a spring washer 12 and a ball bearing 7 to connect the input shaft 6 and the upper housing 5, utilizes the upper housing 5 and a pin 8 to connect to the output shaft 3 having a first sinusoidal surface 31 and a second sinusoidal surface 32, and a stopper 10 is welded to the lower housing 4. The ball 9 is positioned by means of preset grooves in the upper housing 5 and the lower housing 4, so that the ball 9 can only roll on the track defined by the sinusoidal surfaces.

Claims

1. An amplitude-adjustable axial low-frequency vibration-assisted drilling and hole-making device, characterized in that: It includes an input shaft, a lower shell, an upper shell, and an output shaft connected to the machine tool. The bottom of the input shaft is connected to an output shaft with a first sinusoidal surface and a second sinusoidal surface. The upper shell and the lower shell are mounted on the output shaft from bottom to top, and the upper shell and the lower shell are fixedly connected. A ball bearing is provided between the upper shell and the input shaft, and the ball bearing has an interference fit with the upper shell and the input shaft. Several grooves are preset on the bottom end face of the lower shell and the top end face of the upper shell, and balls are placed in the grooves respectively. The balls roll in the grooves and remain tangent to and tightly connected with the first sinusoidal surface and the second sinusoidal surface of the output shaft.

2. The adjustable amplitude axial low-frequency vibration assisted drilling and hole-making device according to claim 1, characterized in that: The output shaft is connected to an ER32 retaining spring at its lower portion, and the ER32 retaining spring is connected to an ER32 collet nut. The ER32 retaining spring is used to clamp the tool.

3. The adjustable amplitude axial low-frequency vibration assisted drilling and hole-making device according to claim 1, characterized in that: The first sinusoidal curved surface and the second sinusoidal curved surface of the output shaft are identical, the curved surface of the first sinusoidal curved surface faces downward, and the curved surface of the second sinusoidal curved surface faces upward.

4. The adjustable amplitude axial low-frequency vibration assisted drilling and hole-making device according to claim 1, characterized in that: The output shaft is a detachable and replaceable component.

5. The adjustable amplitude axial low-frequency vibration assisted drilling and hole-making device according to claim 1, characterized in that: A spring washer is provided between the bottom of the ball bearing and the upper shell for supporting the ball bearing.

6. The adjustable amplitude axial low-frequency vibration assisted drilling and hole-making device according to claim 1, characterized in that: A stopping device is fixedly connected to the lower shell, and the other end of the stopping device is connected to a brake block of the machine tool.

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