An ultrasonic grinding device for cylindrical rollers based on piezoelectric composite waves

Abstract

This invention provides an ultrasonic grinding device for cylindrical rollers based on piezoelectric composite waves, comprising a longitudinal torsional transducer, a piezoelectric tool head, and a spindle turntable. The longitudinal torsional transducer is positioned above the piezoelectric tool head. The upper surface of the spindle turntable is uniformly provided with multiple straight grooves, and cylindrical rollers are uniformly distributed within these grooves. The piezoelectric tool head is positioned above the cylindrical rollers. This invention combines the longitudinal torsional standing wave of the longitudinal torsional transducer with the bending vibration traveling wave of the piezoelectric tool head. The tangential motion of the piezoelectric tool head's particles achieves micro-cutting grinding of the cylindrical roller's curved surface. The high-energy impact generated by the longitudinal torsional transducer in the normal direction achieves deep rolling reinforcement of the cylindrical curved surface. This solves the main problems of low processing efficiency and the inability to achieve surface modification of the cylindrical roller surface in existing processing methods.

Description

Technical Field

[0001] This invention relates to the field of piezoelectric ultrasonic processing technology, and in particular to an ultrasonic grinding device for cylindrical rollers based on piezoelectric composite waves. Background Technology

[0002] Bearings are key fundamental components of equipment and instruments, and their performance directly determines the performance, lifespan, and reliability of major equipment and main products. Bearing rollers are the most critical and vulnerable parts of a bearing; their precision and consistency have a crucial impact on bearing performance and lifespan. Most bearing failures are caused by roller fatigue. Cylindrical rollers, as a type of rolling element, have the ability to withstand high loads due to their line contact with the raceway, making them particularly suitable for heavy-duty and high-speed rotating mechanical equipment, such as high-speed machine tool spindles, wind turbines, and rail locomotives. The surface quality of bearing rollers is determined by the geometric, mechanical, and metallographic properties of both the surface and subsurface layers.

[0003] Ultra-precision machining aims to improve surface geometric accuracy to ensure the fatigue resistance of rollers. It includes traditional machining processes such as centerless grinding and centerless ultra-precision grinding, as well as special machining processes such as electrochemical mechanical finishing and magnetohydrodynamic grinding. Ultra-precision machining primarily emphasizes ultra-high precision constraints on the surface without modifying the workpiece's surface layer. Although centerless grinding has high production efficiency, its machining accuracy is heavily dependent on the machine tool's mechanical structure and precision. Instability in the contact between the workpiece's working surface and wear of components such as the grinding wheel and guide wheel can easily affect the workpiece's machining accuracy.

[0004] Electrochemical mechanical finishing (EMF) uses an electrochemical reaction to corrode the workpiece surface, removing material. The chemically formed oxide film hinders further electrochemical reactions. Then, mechanical grinding removes the oxide film, allowing the electrochemical reaction to continue, thus improving the workpiece surface quality. Magnetorheological abrasive finishing (MRA) achieves material removal by precisely controlling the contact stress and removal depth between the magnetorheological abrasive grains and the workpiece surface. It is suitable for ultra-precision machining of hard and brittle materials with complex curved surfaces. While these two special machining processes can significantly improve workpiece surface accuracy and machining efficiency, they also present problems such as complex machining systems and environmental pollution.

[0005] Ultrasonic rolling is a novel fatigue-resistant manufacturing technology. By applying ultrasonic vibration energy to the rolling tool, the workpiece surface is subjected to high-frequency hammering in the normal direction and mechanical rolling in the tangential direction, thereby increasing residual compressive stress and forming a reinforced modified layer. However, the structure of ultrasonic rolling tools is relatively complex, which can easily lead to ultrasonic energy dissipation and affect processing efficiency. Existing ultrasonic rolling research usually focuses on single cylindrical surfaces and is not applicable to the multiple characteristics of bearing rollers. Summary of the Invention

[0006] The purpose of this invention is to provide an ultrasonic grinding device for cylindrical rollers based on piezoelectric composite waves, so as to solve the problems of low processing efficiency and inability to achieve surface modification of cylindrical rollers in existing processing methods.

[0007] According to one objective of the present invention, the present invention provides an ultrasonic grinding device for cylindrical rollers based on piezoelectric composite waves, comprising a longitudinal torsion transducer, a piezoelectric tool head and a spindle turntable, wherein the longitudinal torsion transducer is positioned above the piezoelectric tool head, the upper end face of the spindle turntable is uniformly provided with a plurality of straight grooves, the cylindrical rollers are uniformly distributed in the straight grooves, and the piezoelectric tool head is positioned above the cylindrical rollers.

[0008] Furthermore, the lower end face of the piezoelectric tool head is in contact with the cylindrical surfaces of all the cylindrical rollers, and a second piezoelectric ceramic ring is attached to the upper surface of the piezoelectric tool head.

[0009] Furthermore, the longitudinal torsion transducer is a sandwich-type longitudinal torsion transducer, which includes a transducer rear cover plate, a first piezoelectric ceramic ring, a transducer front cover plate, and a longitudinal torsion amplitude transformer. The transducer rear cover plate, the first piezoelectric ceramic ring, the transducer front cover plate, and the longitudinal torsion amplitude transformer are connected by pre-tightening bolts.

[0010] Furthermore, the longitudinal torsion amplitude rod has an internal threaded hole in its middle part, and the head end of the pre-tightening bolt is screwed into the internal threaded hole.

[0011] Furthermore, the end face of the longitudinal torsion amplitude transformer contacts the upper surface of the piezoelectric tool head, and a spiral groove is provided on the outer side of the longitudinal torsion amplitude transformer.

[0012] Furthermore, both the rear cover plate and the front cover plate of the transducer are cylindrical.

[0013] Furthermore, the number of the first piezoelectric ceramic rings is two.

[0014] Furthermore, the longitudinal torsion amplitude rod is conical in shape.

[0015] Furthermore, a rotating spindle is provided at the bottom of the spindle turntable, and the rotating spindle is rotatably mounted on the base.

[0016] Furthermore, a two-phase sinusoidal voltage with a phase difference of π / 2 is applied to the second piezoelectric ceramic ring. The second piezoelectric ceramic ring generates two-phase standing waves and synthesizes them into a single-phase traveling wave. The particle on the end face of the piezoelectric tool head generates an elliptical motion trajectory, and the particle tangent simultaneously produces a grinding and cutting action on the cylindrical surfaces of multiple cylindrical rollers.

[0017] The technical solution of this invention combines the longitudinal torsional standing wave of a longitudinal torsional transducer with the bending vibration traveling wave of a piezoelectric tool head. The tangential motion of the piezoelectric tool head's particles achieves micro-cutting and grinding of the cylindrical roller surface; the high-energy impact generated by the longitudinal torsional transducer in the normal direction achieves deep rolling reinforcement of the cylindrical surface. This solves the main problems of low processing efficiency and inability to modify the surface of the cylindrical roller surface in existing processing methods. Attached Figure Description

[0018] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the structure of an embodiment of the present invention;

[0020] Figure 2 This is another structural schematic diagram of an embodiment of the present invention;

[0021] Figure 3 This is a front view of an embodiment of the present invention;

[0022] Figure 4 This is a schematic diagram of the spindle turntable according to an embodiment of the present invention;

[0023] Figure 5 This is a schematic diagram illustrating the traveling wave cutting principle of an embodiment of the present invention;

[0024] In the figure, 1-pre-tightening bolt, 2-transducer rear cover plate, 3-first piezoelectric ceramic ring, 4-transducer front cover plate, 5-longitudinal torsion amplitude rod, 6-piezoelectric tool head, 7-cylindrical roller, 8-spindle turntable, 9-rotating spindle, 10-second piezoelectric ceramic ring. Detailed Implementation

[0025] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0026] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and 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 limiting this invention.

[0027] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the stated features. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified. Furthermore, the terms "installed," "connected," and "linked" should be interpreted broadly; for example, they may refer to a fixed connection, a detachable connection, or an integral connection; they may refer to a mechanical connection or an electrical connection; they may refer to a direct connection or an indirect connection through an intermediate medium; and they may refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0028] Example 1

[0029] like Figures 1-5 As shown,

[0030] An ultrasonic grinding device for cylindrical rollers based on piezoelectric composite waves includes a longitudinal torsion transducer, a piezoelectric tool head 6, and a spindle turntable 8. The longitudinal torsion transducer comprises a transducer rear cover plate 2, two first piezoelectric ceramic rings 3, a transducer front cover plate 4, and a longitudinal torsion amplitude transformer 5. The transducer rear cover plate 2, the two first piezoelectric ceramic rings 3, the transducer front cover plate 4, and the longitudinal torsion amplitude transformer 5 are connected by a pre-tightening bolt 1. An internal threaded hole is provided in the middle of the longitudinal torsion amplitude transformer 5, and the head of the pre-tightening bolt 1 is screwed into the internal threaded hole of the longitudinal torsion amplitude transformer 5 to achieve a pre-tightening effect.

[0031] The longitudinal torsion transducer is placed above the piezoelectric tool head 6, and the end face of the longitudinal torsion amplitude rod 5 is in contact with the upper surface of the piezoelectric tool head 6. The outer side of the longitudinal torsion amplitude rod 5 is provided with a spiral groove. The spiral groove structure on the surface of the longitudinal torsion amplitude rod 5 can convert the one-dimensional longitudinal vibration generated by the longitudinal torsion transducer into a longitudinal torsion composite vibration.

[0032] The type of longitudinal torsion transducer is a sandwich longitudinal torsion transducer. The transducer rear cover plate 2 and the transducer front cover plate 4 of the longitudinal torsion transducer are both cylindrical. The transducer front cover plate 4 in the longitudinal torsion transducer is made of aluminum alloy material for structural design. The transducer rear cover plate 2, the longitudinal torsion amplitude rod 5 and the pre-tightening bolt 1 are all made of 45 steel for structural design.

[0033] In this embodiment, the number of first piezoelectric ceramic rings 3 in the longitudinal torsion transducer is two, to ensure that the transducer rear cover plate 2 and the transducer front cover plate 4 can be connected to electrodes of the same polarity. The longitudinal torsion amplitude transformer 5 is designed in a conical shape to concentrate ultrasonic energy and achieve longitudinal torsion conversion. The piezoelectric tool head 6 uses the dynamic elliptical motion of the end face particles to replace the traditional ultrasonic rolling tool.

[0034] The various parts of the longitudinal torsion transducer are bonded together with adhesive and then fixed and tightened with preload bolts 1, which provide the necessary preload force for the transducer. Normally, the front cover plate 4 of the transducer is connected to the load, while the rear cover plate 2 is unloaded, allowing ultrasonic energy to radiate outwards as much as possible from the front cover plate 4. The longitudinal torsion amplitude transformer 5 amplifies the high-frequency ultrasonic vibration generated by the transducer and converts the longitudinal vibration into a longitudinal-torsional composite vibration through its own helical groove structure. Finally, the longitudinal-torsional composite vibration is output at the end face of the amplitude transformer and transmitted to the piezoelectric tool head 6.

[0035] A rotating spindle 9 is located at the bottom of the spindle turntable 8. The rotating spindle 9 is fixed to the base by bearings and is driven by a drive motor or reducer. The rotating spindle 9 drives the spindle turntable 8 to rotate, thereby causing the cylindrical rollers 7 located on the spindle turntable 8 to rotate. In this embodiment, the spindle turntable 8 has several straight grooves that can be used for direct positioning of batch cylindrical rollers. The piezoelectric tool head 6 contacts the evenly distributed curved surface of the cylindrical rollers simultaneously, and the force is uniform.

[0036] The upper surface of the spindle turntable 8 is uniformly provided with multiple straight grooves. Cylindrical rollers 7 are evenly distributed in these grooves. The piezoelectric tool head 6 is positioned above the cylindrical rollers 7, and its lower end face simultaneously contacts the cylindrical surfaces of all the cylindrical rollers 7. The second piezoelectric ceramic ring 10 is adhered to the upper surface of the piezoelectric tool head 6. Based on the inverse piezoelectric effect of piezoelectric ceramics, a two-phase sinusoidal voltage with a phase difference of π / 2 is applied to the second piezoelectric ceramic ring 10. This generates a two-phase standing wave on the second piezoelectric ceramic ring 10, i.e., the piezoelectric tool head 6, which is then synthesized into a single traveling wave. The particles on the end face of the piezoelectric tool head 6 generate an elliptical trajectory, and the tangent of these particles simultaneously grinds and cuts the cylindrical surfaces of the multiple cylindrical rollers 7.

[0037] When the longitudinal torsion transducer and the piezoelectric tool head 6 work simultaneously, in the normal direction, the high-frequency longitudinal vibration generated by the longitudinal torsion transducer produces high-energy deep rolling reinforcement on the curved surface of the cylindrical roller 7 through the piezoelectric tool head 6. In the tangential direction, the torsional vibration generated by the longitudinal torsion transducer is coupled with the traveling wave rolling action of the particles on the end face of the piezoelectric tool head 6, realizing the grinding and cutting of the curved surface of a batch of cylindrical rollers 7.

[0038] Based on the friction drive principle of traveling wave ultrasonic motors, the microscopic traveling wave elliptical motion of stator particles can be converted into the macroscopic rotational motion of the rotor, resulting in material wear and fatigue failure at the rotor contact surface. Due to the inverse piezoelectric effect of piezoelectric ceramics and the circumferential travel characteristics of traveling waves, the dynamic elliptical motion of the particles on the end face of the piezoelectric tool head 6 generates high-frequency cutting stress on the curved surface of the cylindrical roller 7. The high-frequency mechanical vibration generated in the vertical direction by the longitudinal torsional transducer produces high-energy impact and surface modification enhancement on the roller surface. The superposition of the torsional vibration generated by the longitudinal torsional transducer and the high-frequency cutting stress generated by the particles on the end face of the piezoelectric tool head significantly improves the grinding quality of the cylindrical surface of the roller.

[0039] This invention discloses an ultrasonic grinding device for cylindrical rollers based on piezoelectric composite waves. It utilizes the combined effect of longitudinal torsional standing waves and bending traveling waves to achieve micro-cutting and surface modification of the curved surfaces of batches of cylindrical rollers. Compared with existing bearing roller surface processing technologies, this invention enables micro-cutting and surface modification of the surfaces of batches of cylindrical rollers using piezoelectric composite waves. The orthogonal coupling of the longitudinal torsional standing waves and bending traveling waves generates high-frequency cutting stress and surface modification enhancement on the cylindrical roller surfaces. The dynamic elliptical motion of the piezoelectric tool head particles replaces the traditional ultrasonic rolling tool, solving the problems of complex structure and easy dissipation of ultrasonic energy in ultrasonic rolling tools. Several straight grooves of corresponding sizes are designed on the upper surface of the spindle turntable to position the rollers, significantly improving processing efficiency and stability. This invention achieves surface modification processing of the curved surfaces of batches of cylindrical rollers, improving the efficiency and surface quality of ultra-precision machining of cylindrical rollers.

[0040] This invention discloses an ultrasonic grinding device for cylindrical rollers based on piezoelectric composite waves. It combines the longitudinal torsional standing wave of a longitudinal torsional transducer with the bending vibration traveling wave of a piezoelectric tool head. The tangential motion of the piezoelectric tool head's particles achieves micro-cutting grinding of the cylindrical roller's curved surface. The high-energy impact generated by the longitudinal torsional transducer in the normal direction achieves deep rolling reinforcement of the cylindrical surface. This invention solves the main problems of low processing efficiency and the inability to modify the surface layer of the cylindrical roller in existing processing methods.

[0041] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. An ultrasonic grinding device for cylindrical rollers based on piezoelectric composite waves, characterized in that, The device includes a longitudinal torsion transducer, a piezoelectric tool head, and a spindle turntable. The longitudinal torsion transducer is positioned above the piezoelectric tool head. The upper surface of the spindle turntable has multiple evenly distributed straight slots, with cylindrical rollers evenly distributed within these slots. The piezoelectric tool head is positioned above the cylindrical rollers. The longitudinal torsion transducer is a sandwich-type transducer, comprising a transducer rear cover plate, a first piezoelectric ceramic ring, a transducer front cover plate, and a longitudinal torsion amplitude transformer. The cover plate and the longitudinal torsion amplitude rod are connected by pre-tightening bolts; the lower end face of the piezoelectric tool head is in contact with the cylindrical surfaces of all the cylindrical rollers simultaneously, and a second piezoelectric ceramic ring is attached to the upper surface of the piezoelectric tool head; a two-phase sinusoidal voltage with a phase difference of π / 2 is applied to the second piezoelectric ceramic ring, the second piezoelectric ceramic ring generates two-phase standing waves and synthesizes them into a single-phase traveling wave, the end face particles of the piezoelectric tool head generate elliptical motion trajectories, and the tangent of the particles simultaneously produces a grinding and cutting action on the cylindrical surfaces of multiple cylindrical rollers.

2. The cylindrical roller ultrasonic grinding device based on piezoelectric composite waves according to claim 1, characterized in that, The longitudinal torsion amplitude rod has an internal threaded hole in the middle, and the head end of the pre-tightening bolt is screwed into the internal threaded hole.

3. The ultrasonic grinding device for cylindrical rollers based on piezoelectric composite waves according to claim 1, characterized in that, The end face of the longitudinal torsion amplitude transformer is in contact with the upper surface of the piezoelectric tool head, and a spiral groove is provided on the outer side of the longitudinal torsion amplitude transformer.

4. The cylindrical roller ultrasonic grinding device based on piezoelectric composite waves according to claim 1, characterized in that, Both the rear cover plate and the front cover plate of the transducer are cylindrical.

5. The ultrasonic grinding device for cylindrical rollers based on piezoelectric composite waves according to claim 1, characterized in that, The number of the first piezoelectric ceramic rings is two.

6. The cylindrical roller ultrasonic grinding device based on piezoelectric composite waves according to claim 1, characterized in that, The longitudinal torsion amplitude rod is conical in shape.

7. The ultrasonic grinding device for cylindrical rollers based on piezoelectric composite waves according to claim 1, characterized in that, The bottom of the spindle turntable is provided with a rotating spindle, which is rotatably mounted on the base.

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