Mechanical torsional vibration main shaft device

Abstract

The invention belongs to the technical field of machining, particularly discloses a mechanical torsional vibration main shaft device, and aims to solve the problem of efficient cutting of difficult-to-machine materials such as carbon fibers and glass fibers. The device adopts a coaxial double-input structural design and comprises a connecting rod input shaft, a cam input shaft, a connecting rod cam torsional vibration generating mechanism and an output shaft. The connecting rod mechanism is of a parallelogram structure formed by hinging two short rods and two long rods, the cam mechanism is in internally tangent contact with the connecting rod mechanism through a conjugate cam assembly, the transmission ratio is periodically changed through a cam profile, and torsional vibration superposition is achieved. The output shaft is connected with a cutter, and main cutting motion and controllable torsional vibration motion are integrally output. Variable-frequency torsional vibration adjustment is achieved in a mechanical mode, the high-power bearing capacity is achieved, the structure is compact, the device is suitable for large workpieces and moving machining scenes, the machining efficiency and surface quality of materials difficult to machine are remarkably improved, and the advantages of being high in rigidity, low in friction, wide in process adaptability and the like are achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of mechanical processing, and in particular to a mechanical torsional vibration spindle device. Background Art

[0002] During machining processes like drilling, milling, and grinding, applying vibrations of a specific frequency and amplitude to the tool or workpiece has been shown to reduce cutting forces and heat, minimizing tool sticking and chipping, thereby significantly improving machining quality and efficiency and extending tool life. This technology has been widely used in the manufacture of difficult-to-machine materials, deep small holes, and precision parts.

[0003] Currently, vibration machining technologies can be categorized by frequency into ultrasonic (high-frequency) and low-frequency vibrations; and by direction into axial (longitudinal) and torsional vibrations. Vibration methods of varying frequencies and directions can significantly differ in machining results, applicable materials, and implemented structures.

[0004] Ultrasonic vibration machining is currently the most mature vibration machining method. Relevant patents include CN2082651U, CN203900554U, CN103949687A, CN2527382Y, etc. These technologies all use piezoelectric or magnetostrictive transducers to excite high-frequency axial vibrations, and have significant machining effects on hard and brittle non-metallic materials such as glass and ceramics. However, due to the limited output power of the ultrasonic generator, it is difficult to meet the machining needs of high-strength fiber composite materials such as carbon fiber and glass fiber.

[0005] Low-frequency torsional vibration machining, due to its high power density, is more suitable for cutting fiber composite materials. For example, patents CN108115755A and CN108044695A disclose a mechanical torsional vibration table based on a lever and cam mechanism, and another based on a spatial cam, respectively. These devices utilize various mechanisms to achieve torsional vibration motion on a worktable mounted on the workpiece, thereby enabling torsional vibration machining. However, these torsional vibration tables are not suitable for large workpieces.

[0006] Therefore, there is an urgent need for a mechanical torsional vibration spindle device to solve the problem of efficient cutting of difficult-to-process materials such as carbon fiber and glass fiber. Summary of the Invention

[0007] The purpose of the present invention is to provide a mechanical torsional vibration spindle device, which is based on a parallelogram connecting rod and a cam mechanism, can superimpose torsional vibration on the spindle, and can be suitable for processing carbon fiber and glass fiber board materials after clamping a drill bit or a milling cutter.

[0008] To achieve the above-mentioned objectives, the present invention provides the following solutions: a mechanical torsional vibration spindle device, comprising: a connecting rod input shaft, a cam input shaft, a connecting rod cam torsional vibration generating mechanism and an output shaft, wherein the connecting rod input shaft and the cam input shaft are coaxially arranged; the connecting rod cam torsional vibration generating mechanism comprises a cam mechanism and a connecting rod mechanism that cooperate with each other; the connecting rod mechanism comprises two short rods that are transmission-connected to the connecting rod input shaft, and two long rods that are transmission-connected to the output shaft, and the two short rods and the two long rods are hinged to each other to form a parallelogram; the cam mechanism comprises a conjugate cam assembly, which contacts the connecting rod mechanism and periodically changes the transmission ratio of the connecting rod mechanism through the cam profile; the output shaft is used to connect the tool, transmit power through the connecting rod cam torsional vibration generating mechanism and superimpose the torsional vibration motion.

[0009] Furthermore, a deep groove ball bearing is installed at the end of the long rod, and the deep groove ball bearing is in inscribed contact with the conjugate cam assembly.

[0010] Furthermore, the short rod and the long rod are hinged by a pin, the connecting rod input shaft is connected to the input flange, the output shaft is connected to the output flange, the center of the short rod is hinged to the input flange to form a rotating pair, and the center of the long rod is hinged to the output flange to form a rotating pair.

[0011] Furthermore, a graphite copper sleeve is embedded in the pin shaft of the connecting rod mechanism to reduce friction, and is fixed by a shaft retaining spring.

[0012] Furthermore, the conjugate cam assembly includes conjugate cam 1, a spacer and conjugate cam 2. The conjugate cam 1 and the conjugate cam 2 are connected through the spacer and the positioning pin. The contour curve thereof is a periodically changing curve, which is used to force the connecting rod mechanism to deform periodically to achieve torsional vibration output.

[0013] Furthermore, the cam mechanism also includes an input end cam mounting seat and an output end cam mounting seat, the input end cam mounting seat is connected to the cam input shaft through screws, and the output end cam mounting seat supports the output shaft through an angular contact ball bearing.

[0014] Furthermore, the angular displacement β of the output shaft and the angular displacement α of the connecting rod input shaft satisfy the following relationship:

[0015] β=Asin(Na)+α

[0016] Where A is the amplitude of torsional vibration, and N is the number of fundamental frequency torsional vibrations.

[0017] Furthermore, assuming that the speed of the connecting rod input shaft is n1 and the speed of the cam input shaft is n2, the composite torsional vibration frequency N' satisfies the relationship:

[0018] N'=N(n1±n2) / n1

[0019] Where N is the fundamental frequency torsional vibration frequency. When the connecting rod input shaft and the cam input shaft rotate in opposite directions, a "+" sign is used, and when the rotation directions are the same, a "-" sign is used. Mechanical adjustment of the torsional vibration frequency is achieved by adjusting the rotation speed n2 of the cam input shaft.

[0020] Furthermore, the profile curve of the conjugate cam assembly is calculated by Hertzian contact strength.

[0021] Furthermore, the output shaft is supported and mounted on the output end cam mounting seat through two angular contact ball bearings, and is axially fixed by a stop washer and a slotted round nut.

[0022] Compared with the prior art, the present invention has at least the following beneficial effects:

[0023] Embodiments of the present invention provide a mechanical torsional vibration spindle device based on a parallelogram connecting rod and cam mechanism that superimposes torsional vibration on the spindle. This device features a compact structure and small size. Compared to table-based torsional vibration, it is not limited by workpiece size and can also be used in mobile or portable machining environments. Compared to ultrasonic torsional vibration, this device offers higher power and is suitable for machining difficult-to-machine materials such as carbon fiber and fiberglass sheets. Furthermore, the device achieves variable-frequency torsional vibration through cam rotation, expanding its machining process range. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0025] Figure 1 Schematic diagram of the structure of the mechanical torsional vibration spindle device of the present invention;

[0026] Figure 2 An exploded view of the mechanical torsional vibration spindle device of the present invention;

[0027] Figure 3 Schematic diagram of the assembly of the cam mechanism and the connecting rod mechanism in the mechanical torsional vibration spindle device of the present invention Figure 1 ;

[0028] Figure 4 Schematic diagram of the assembly of the cam mechanism and the connecting rod mechanism in the mechanical torsional vibration spindle device of the present invention Figure 2 ;

[0029] Figure 5 Schematic diagram of the assembly of the cam mechanism and the connecting rod mechanism in the mechanical torsional vibration spindle device of the present invention Figure 3;

[0030] Figure 6 Schematic diagram of the structure of the cam mechanism in the mechanical torsional vibration spindle device of the present invention;

[0031] Figure 7 This is a graph showing the actual contours of the two conjugate cams in the mechanical torsional vibration spindle device of the present invention.

[0032] In the figure: 1. Connecting rod input shaft; 2. Cam input shaft; 3. Cam mechanism; 31. Input cam mounting seat; 32. Conjugate cam assembly; 321. Conjugate cam 1; 322. Spacer; 323. Conjugate cam 2; 33. Output cam mounting seat; 4. Output shaft; 5. Flat key; 6. Input flange; 7. Connecting rod mechanism; 701. Short rod; 702. Long rod; 703. Pin; 704. Graphite copper sleeve; 705. Shaft retaining ring; 706. Deep groove ball bearing; 8. Output flange; 9. Angular contact ball bearing; 10. Lock washer; 11. Slotted round nut; 12. ER chuck; 13. ER nut. DETAILED DESCRIPTION

[0033] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0034] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0035] Reference Figure 1As shown, this embodiment provides a mechanical torsional vibration spindle device comprising a coaxial dual input shaft, a connecting rod cam torsional vibration generating mechanism, and an output shaft 4. The coaxial dual input shaft comprises a connecting rod input shaft 1 and a cam input shaft 2 at the input end, which are coaxially arranged. The connecting rod cam torsional vibration generating mechanism comprises a cam mechanism 3 and a connecting rod mechanism 7 that cooperate with each other. The connecting rod input shaft 1 is connected to the main drive motor and fixed to the input flange 6 via a flat key 5. It drives the connecting rod mechanism 7 to rotate, providing the main cutting speed of the spindle, which is equal to the nominal processing speed of the spindle. The cam input shaft 2 is connected to an independent cam drive motor and cooperates with the cam mechanism 3. Its end is fixed to the cam mounting seat via screws, driving the conjugate cam assembly 32 to rotate. The cam profile periodically changes the transmission ratio of the connecting rod mechanism 7, superimposing the torsional vibration motion. It should be understood that the cam input shaft 2 is a hollow shaft design, allowing the connecting rod input shaft 1 to pass through it, achieving a coaxial arrangement. This coaxial design saves space and avoids the complexity of a parallel dual-axis arrangement. One end of the output shaft 4 transmits power through the connecting rod cam torsional vibration generating mechanism, and the other end is connected to the tool, ultimately achieving torsional vibration processing of the workpiece.

[0036] In a specific embodiment, Figure 2 As shown, the cam mechanism 3 includes an input cam mounting seat 31, a conjugate cam assembly 32, and an output cam mounting seat 33, all of which are fastened together by bolts. The connecting rod mechanism 7 is located inside the cam mechanism 3 and cooperates with the conjugate cam assembly 32. The input cam mounting seat 31 is connected to the cam input shaft 2 via screws. Both the input cam mounting seat 31 and the output cam mounting seat 33 are cam disc structures with a hollow interior and a central hole. The central hole can accommodate the connecting rod mechanism 7, and the connecting rod input shaft 1 and output shaft 4 can pass through the central hole.

[0037] In a specific embodiment, Figures 3 to 5 As shown, the conjugate cam assembly 32 includes a conjugate cam 1 321, a spacer 322, and a conjugate cam 2 323. The conjugate cam 1 321 and the conjugate cam 2 323 are connected by the spacer 322 and the positioning pin. The conjugate cams (the conjugate cam 1 321 and the conjugate cam 2 323) are inscribed in the deep groove ball bearing 706 on the diagonal line of the connecting rod mechanism 7. The profile curve of the conjugate cam is designed to be a periodic variation curve to ensure that the output end angular velocity ω β It presents periodic speed change, and forces the connecting rod mechanism 7 to deform periodically through the cam profile, thereby realizing the forward and reverse torsional vibration of the output shaft 4.

[0038] In some optional embodiments, the profiles of the two conjugate cams in the conjugate cam assembly 32 correspond to the motion trajectories of the two pairs of bearings in the parallelogram linkage 7. The profiles are optimized using Hertzian contact strength calculations to accommodate high-load conditions. Assuming the angular displacement of the connecting rod input shaft 1 is α and the angular displacement of the output shaft 4 is β, the following equation (1) is designed to achieve output torsional vibration:

[0039] β=Asin(Na)+α

[0040] Where A is the amplitude of the torsional vibration, and N is the number of fundamental frequency torsional vibrations, that is, the number of torsional vibrations of the connecting rod mechanism 7 around the cam. From the above relationship 1, we can get relationship 2:

[0041] ω β =ω a [1+ANcos(Nω a t)]

[0042] Where, ω α is the input angular velocity, ω β is the angular velocity of the output end.

[0043] From the second relation, we can see that the output angular velocity ω β The angular velocity ω of the input end is periodically greater than or less than the uniform rotation α The changing law of can realize torsional vibration motion.

[0044] According to the actual processing requirements, select A, torsional vibration frequency N and processing main speed (corresponding to ω α ), the relationship 1 can be determined; after designing the rod length according to the structure and strength requirements, the theoretical contour curve of the conjugate cam can be obtained according to the relationship 1; after selecting the deep groove ball bearing 706 according to the Hertz contact strength requirements, the actual contour line of the conjugate cam can be obtained by the envelope principle.

[0045] like Figure 7 As shown, the solid line and the dotted line are schematic diagrams of the two actual contour curves of the two conjugate cams when the torsional vibration frequency N is 12.

[0046] Considering the requirements of variable frequency torsional vibration in actual processing, this patent design uses the conjugate cam as a rotatable component to achieve mechanical frequency conversion without changing the input angular velocity. Assuming the speed of the connecting rod mechanism 7 is n1 and the speed of the conjugate cam is n2, the composite torsional vibration frequency N' satisfies the relationship three:

[0047] N'=N(n1±n2) / n1

[0048] In the formula, the “+” sign is used when the two rotation directions are in opposite directions, and the “-” sign is used when the two rotation directions are in the same direction.

[0049] In a specific embodiment, Figure 6As shown, the connecting rod mechanism 7 in the connecting rod cam torsional vibration generating mechanism is a parallelogram mechanism, comprising two short rods 701 and two long rods 702. The two short rods 701 and the two long rods 702 are hinged via a pin 703. A graphite copper sleeve 704 is embedded in the pin 703 to reduce friction, and the pin 703 is secured with a shaft retaining ring 705. The center of the short rod 701 is hinged to the input flange 6 via a graphite copper sleeve 704 to form a revolving pair. The center of the long rod 702 is hinged to the output flange 8 to form a revolving pair. The end of the long rod 702 is mounted with a deep groove ball bearing 706 via a pin 703, which is in internal contact with the conjugate cam assembly 32. This connecting rod mechanism 7 is used to transmit the uniform rotation of the input flange 6 to the output flange 8, and to achieve torsional vibration output by superimposing periodic deformation on the cam mechanism 3.

[0050] Specifically, two short rods 701 are connected to a long rod 702 via four pins 703, forming a quadrilateral mechanism. Circular holes are formed at the pins 703 on both the short and long rods 701 and 702, and graphite copper sleeves 704 are embedded in them. One end of the pin 703 is axially positioned by a shoulder through its T-shaped structure, while the other end is axially positioned and secured by a retaining spring 705, forming four revolute pairs. Circular holes are formed at the ends of the two long rods 702, and four deep-groove ball bearings 706 are secured via the T-shaped pins 703. The other ends of the pins 703 are secured by retaining springs 705. Circular holes connecting the input and output ends are respectively formed at the center of the short and long rods 701 and 702, and graphite copper sleeves 704 are embedded in these holes. In this embodiment, the input end drives the input flange 6 to rotate at a constant speed in a certain direction, thereby driving the rotation of the connecting rod mechanism 7. The conjugate cam assembly 32 controls the forward and reverse deformation of the connecting rod mechanism 7 through each set of contour curves designed in this embodiment, thereby realizing the forward and reverse speed change rotation of the output flange 8, and then driving the output shaft 4 to rotate forward and reverse to obtain the designed torsional vibration motion.

[0051] Furthermore, the output shaft 4 is supported and mounted on the output cam mounting seat 33 via two angular contact ball bearings 9 and axially secured by a retaining washer 10 and a slotted round nut 11. A tapered hole is provided at the end of the output shaft 4, which is positioned and clamped by an ER chuck 12 and ER nut 13 to allow tools such as drills or milling cutters to be positioned and clamped for torsional vibration machining.

[0052] Furthermore, one end of the cam input shaft 2 is connected to the cam drive motor via a set of screws, and the other end is connected to the input cam mounting seat 31 via a set of screws. The input cam mounting seat 31 is then connected to the conjugate cam assembly 32 and the output cam mounting seat 33 via a set of bolts. Through this connection, the driving force of the cam drive motor is transmitted to the conjugate cam. By adjusting the direction and speed of the cam drive motor through methods such as commutation and frequency modulation, variable frequency torsional vibration can be achieved to meet the needs of different processing techniques.

[0053] The mechanical torsional vibration spindle device provided by the embodiment of the present invention achieves a technological breakthrough in directly superimposing controllable torsional vibration motion on the tool end through an innovative coaxial dual-input shaft design combined with a parallelogram connecting rod and a conjugate cam mechanism 3. Its core advantage lies in the use of a mechanical transmission structure to coaxially integrate the main cutting power (through the connecting rod input shaft 1) and the torsional vibration force (through the cam input shaft 2), and the conjugate cam periodically squeezes the parallelogram connecting rod to change the transmission ratio, so that the output shaft 4 superimposes the forward and reverse speed change motion on the basis of uniform rotation, forming a composite torsional vibration effect. The device reduces friction loss by designing the inscribed contact cam profile of the deep groove ball bearing 706, and ensures operational reliability under high-load conditions by combining the articulated structure of the graphite copper sleeve 704 and the cam curve with optimized Hertzian contact strength. In particular, by independently adjusting the speed n2 of the cam input shaft 2, the torsional vibration frequency can be changed in real time, achieving dynamic frequency modulation within the range of 5-120Hz, and adapting to different processing requirements without stopping the machine. Compared to the defect of traditional torsional vibration tables that are limited by the size of the workpiece, this device directly applies torsional vibration to the cutting tool, so that large carbon fiber plates, wind turbine blades and other workpieces can be efficiently processed without vibration; compared to the problem of insufficient power of ultrasonic vibration solutions, the purely mechanical transmission structure can withstand high-power cutting of more than 5kW, significantly improving the processing efficiency of difficult-to-process materials such as carbon fiber and glass fiber. In addition, the coaxial compact design saves 30% of space compared to the parallel dual-axis layout. Combined with the output shaft 4 structure supported by angular contact ball bearings 9, it has high rigidity and portability, and can be adapted to robot mobile processing scenarios. Through the three major innovations of mechanical variable frequency torsional vibration, high power density cutting and unlimited workpiece size, this technology provides a new solution for the efficient and precise processing of difficult-to-process materials in aerospace, new energy and other fields.

[0054] In the description of the present invention, it should be understood that the terms "longitudinal", "transverse", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0055] The embodiments described above are merely descriptions of preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Without departing from the spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by persons skilled in the art should fall within the scope of protection defined by the claims of the present invention.

Claims

1. A mechanical torsional vibration spindle device, characterized in that: The invention comprises a connecting rod input shaft (1), a cam input shaft (2), a connecting rod cam torsional vibration generating mechanism and an output shaft (4), wherein the connecting rod input shaft (1) and the cam input shaft (2) are coaxially arranged; the connecting rod cam torsional vibration generating mechanism comprises a cam mechanism (3) and a connecting rod mechanism (7) that cooperate with each other; the connecting rod mechanism (7) comprises two short rods (701) that are transmission-connected to the connecting rod input shaft (1), and two long rods (702) that are transmission-connected to the output shaft (4), and the two short rods (701) and the two long rods (702) are hinged to each other to form a parallelogram; the cam mechanism (3) comprises a conjugate cam assembly (32), and the conjugate cam assembly (32) contacts the connecting rod mechanism (7) and periodically changes the transmission ratio of the connecting rod mechanism (7) through a cam profile; the output shaft (4) is used to connect a tool, transmit power through the connecting rod cam torsional vibration generating mechanism, and superimpose torsional vibration motion.

2. The mechanical torsional vibration spindle device according to claim 1, characterized in that: A deep groove ball bearing (706) is installed at the end of the long rod (702), and the deep groove ball bearing (706) is in internal contact with the conjugate cam assembly (32).

3. The mechanical torsional vibration spindle device according to claim 2, characterized in that: The short rod (701) and the long rod (702) are hinged via a pin (703); the connecting rod input shaft (1) is connected to an input flange (6); the output shaft (4) is connected to an output flange (8); the center of the short rod (701) is hinged to the input flange (6) to form a rotation pair; the center of the long rod (702) is hinged to the output flange (8) to form a rotation pair.

4. The mechanical torsional vibration spindle device according to claim 3, characterized in that: A graphite copper sleeve (704) is embedded in the pin shaft (703) of the connecting rod mechanism (7) to reduce friction, and is fixed by a shaft retaining spring (705).

5. The mechanical torsional vibration spindle device according to claim 1, characterized in that: The conjugate cam assembly (32) includes a conjugate cam 1 (321), a spacer (322) and a conjugate cam 2 (323). The conjugate cam 1 (321) and the conjugate cam 2 (323) are connected via the spacer (322) and a positioning pin. The contour curve thereof is a periodically changing curve, which is used to force the connecting rod mechanism (7) to deform periodically to achieve torsional vibration output.

6. The mechanical torsional vibration spindle device according to claim 1 or 5, characterized in that: The cam mechanism (3) further comprises an input-end cam mounting seat (31) and an output-end cam mounting seat (33); the input-end cam mounting seat (31) is connected to the cam input shaft (2) via screws, and the output-end cam mounting seat (33) supports the output shaft (4) via an angular contact ball bearing (9).

7. The mechanical torsional vibration spindle device according to claim 1 or 5, characterized in that: The angular displacement β of the output shaft (4) and the angular displacement α of the connecting rod input shaft (1) satisfy the following relationship: β=Asin(Na)+α Where A is the amplitude of torsional vibration, and N is the number of fundamental frequency torsional vibrations.

8. The mechanical torsional vibration spindle device according to claim 7, characterized in that: Assuming that the rotation speed of the connecting rod input shaft (1) is n1 and the rotation speed of the cam input shaft (2) is n2, the composite torsional vibration frequency N' satisfies the relationship: N'=N(n1±n2) / n1 Wherein, N is the fundamental frequency torsional vibration frequency; when the connecting rod input shaft (1) and the cam input shaft (2) rotate in opposite directions, a "+" sign is taken, and when the rotation directions are the same, a "-" sign is taken, and the torsional vibration frequency is mechanically adjusted by adjusting the rotation speed n2 of the cam input shaft (2).

9. The mechanical torsional vibration spindle device according to claim 8, characterized in that: The profile curve of the conjugate cam assembly (32).

10. The mechanical torsional vibration spindle device according to claim 6, characterized in that: The output shaft (4) is supported and mounted on the output end cam mounting seat (33) through two angular contact ball bearings (9), and is axially fixed by a stop washer (10) and a slotted round nut (11).

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