High-efficiency cooling grinding wheel applied to ultrasonic machining

Abstract

The application discloses a high-efficiency cooling grinding wheel applied to ultrasonic machining, relates to the technical field of ultrasonic auxiliary grinding machining tools, and comprises an upper ultrasonic grinding wheel base rod and a lower ultrasonic grinding wheel grinding head, and the ultrasonic grinding wheel base rod and the ultrasonic grinding wheel grinding head are integrated structures; the ultrasonic grinding wheel base rod is hollow inside and extends to the bottom of the ultrasonic grinding wheel grinding head but does not penetrate through; a sleeve is connected or interference fitted in the ultrasonic grinding wheel base rod; the sleeve is hollow inside and serves as a main flow channel of the cooling liquid; the hollow diameter of the sleeve, namely the main flow channel of the cooling liquid, can be changed; a plurality of round holes are arranged in the grinding wheel grinding head and serve as cooling liquid flow channels of the grinding head; the inlet of the cooling liquid flow channels of the grinding head is connected with the end of the main cooling liquid flow channel; the outlet of the cooling liquid flow channels of the grinding head is located at a machining position in grinding; the cooling liquid outlet of the grinding head is machined with a cooling liquid groove; and the main cooling liquid flow channel and the cooling liquid flow channels of the grinding head are provided with a rifling structure with variable pitch and number.

Description

Technical Field

[0001] The present invention relates to the technical field of ultrasonic-assisted grinding tools, and in particular to a high-efficiency cooling grinding wheel used for ultrasonic machining. Background Art

[0002] The grinding wheel is the most important processing tool in the grinding process. It acts directly on the workpiece. Through the rotation of the grinding wheel, the abrasive grains on the grinding wheel cut the surface of the workpiece to remove the workpiece material. In the traditional grinding process, the relative movement between the workpiece and the grinding wheel generates a large amount of heat. This will not only cause burns on the workpiece surface, residual stress and micro cracks, but may also shorten the service life of the grinding wheel and reduce processing efficiency. Ultrasonic-assisted grinding is a processing method that causes the grinding wheel to vibrate at high frequency while rotating and grinding to remove workpiece material. Ultrasonic processing is a process in which an ultrasonic generator generates a high-frequency electrical oscillation signal, which is converted into ultrasonic frequency mechanical vibration through an ultrasonic transducer. The ultrasonic vibration amplitude is amplified by the amplitude rod and drives the tool grinding wheel to generate vibration of the corresponding frequency, so that periodic processing is formed between the tool and the workpiece. It is widely used in ultra-precision machining and manufacturing.

[0003] Ultrasonic-assisted grinding improves traditional grinding performance by creating a "micro-lubrication" effect between the grinding wheel and the workpiece, reducing the coefficient of friction and, in turn, lowering grinding forces. Ultrasonic waves can more effectively break down the material's microstructure, accelerating the material removal process. This significantly increases material removal rates, particularly in the machining of hard and brittle materials such as ceramics, glass, and composites. Furthermore, the intermittent contact caused by vibration reduces heat accumulation, effectively preventing thermal damage and improving the dimensional accuracy and surface integrity of the workpiece.

[0004] However, the introduction of ultrasonic-assisted machining still generates a large amount of grinding heat due to the high-speed friction between the abrasive particles and the workpiece. If the heat cannot be dissipated in a timely and effective manner, many defects will be caused on the surface of the workpiece, affecting the machining quality. Especially when machining with a large depth of cut, more grinding heat will be generated, so the heat dissipation problem of the grinding wheel is extremely important. At present, ultrasonic-assisted grinding using ordinary grinding wheels usually adopts a cooling method of adding coolant. Due to the air barrier effect caused by the high-speed rotation of the grinding wheel, the coolant is generally only cooled near the machining area, and a small amount can enter the interior of the machining area. The cooling effect is limited and the utilization rate of the coolant is low. Therefore, the cooling and heat dissipation problem of ultrasonic-assisted grinding needs to be solved urgently. In addition, in ultrasonic-assisted grinding, due to the high-frequency vibration of the grinding wheel, the grinding wheel not only scratches the workpiece but also impacts the workpiece, so more grinding chips are generated, and the grinding chips are larger in volume. The presence of a large amount of debris will significantly reduce the surface quality of the ground workpiece. Ultrasonic-assisted grinding using traditional grinding wheels does not consider the problem of removing grinding chips. Although there is external coolant, the flow rate of the external coolant is low and it cannot take out all the grinding chips. This is a problem that needs to be solved in the current ultrasonic-assisted grinding process. Summary of the Invention

[0005] To overcome the problems of traditional external coolant ineffectively cooling the grinding work area and difficulty removing grinding debris, a highly efficient cooling grinding wheel for ultrasonic machining is provided. The present invention provides an ultrasonic cavitation chamber within the inner cavity of the sleeve, utilizing the high-impact micro-jet generated by ultrasound to remove grinding debris and prevent it from damaging the machined surface. The addition of rifling improves the internal cooling efficiency of the grinding wheel, and the flow rate can be adjusted by adjusting the pitch and number of rifling. Hydrophilic treatment of the abrasive grains of the grinding wheel helps improve coolant utilization. Designing the grinding wheel size based on ultrasonic parameters using the nodes and antinodes of standing waves helps maximize the ultrasonic amplitude and improve the material removal rate.

[0006] The technical means adopted in the present invention are as follows:

[0007] A high-efficiency cooling grinding wheel for ultrasonic machining comprises an upper ultrasonic grinding wheel base rod and a lower ultrasonic grinding wheel grinding head, wherein the ultrasonic grinding wheel base rod and the ultrasonic grinding wheel grinding head are an integrated structure; a coaxial hole is provided inside the ultrasonic grinding wheel base rod and extends to the bottom of the ultrasonic grinding wheel grinding head but does not penetrate through the ultrasonic grinding wheel base rod; a sleeve is connected inside the ultrasonic grinding wheel base rod by interference fit or threading; the interior of the sleeve is a hollow structure with a preset inner diameter, which serves as a main coolant channel; a plurality of circular holes are uniformly distributed inside the ultrasonic grinding wheel grinding head as coolant channels for the grinding head; an inlet of the coolant channel for the grinding head is connected to an end of the coolant main channel; an outlet of the coolant channel for the grinding head is located at a grinding machining position, and a coolant tank is processed at the outlet of the coolant channel for the grinding head; a rifling structure is provided in the coolant main channel and the inner cavity of the coolant channel for the grinding head.

[0008] Furthermore, the cooling liquid flow channel of the grinding head forms a certain angle with the main cooling liquid flow channel, and is divided into an upper end face structure, a lower end face structure, and a side face structure according to the different angles formed.

[0009] The inlet of the cooling liquid flow channel of the upper end surface type grinding head is connected to the bottom end of the cooling liquid main channel, and the outlet of the cooling liquid flow channel of the grinding head is arranged on the upper end surface of the grinding wheel grinding part;

[0010] The inlet of the cooling liquid flow channel of the grinding head of the lower end surface type structure is connected to the bottom end of the cooling liquid main channel, and the outlet of the cooling liquid flow channel of the grinding head is arranged on the lower end surface of the grinding wheel grinding part;

[0011] The inlet of the cooling liquid flow channel of the grinding head with the side structure is connected to the bottom end of the cooling liquid main channel, and the outlet of the cooling liquid flow channel of the grinding head is arranged on the side of the grinding wheel grinding part.

[0012] Furthermore, the diameter of the hollow structure inside the sleeve can be changed, specifically including a step-shaped diameter change type and an arc-shaped diameter change type.

[0013] Furthermore, a cavity is provided at the lower end of the sleeve, serving as an ultrasonic cavitation chamber.

[0014] Further, the twist direction and angle of the cooling liquid main flow channel are the same as those of the grinding head cooling liquid flow channel, and the type of the twist includes equal twist, variable twist, mixed twist, equal width twist and wedge twist.

[0015] Further, the cross section of the grinding head cooling liquid flow channel is circular, and the diameter is not more than 1 / 3 of the thickness of the ultrasonic grinding head, the shape and size of the cooling liquid groove are the same, and the shape of the cooling liquid groove includes straight line, curve or preset irregular line.

[0016] Further, the outer part of the grinding wheel is processed by electroplating process, coating process or ion implantation to have a hydrophilic surface, and the surface of the grinding wheel and the abrasive particles are both hydrophilic.

[0017] Further, the shape and size of the circular hole are the same, and the angle formed by each circular hole and the cooling liquid main flow channel is the same, and each circular hole is uniformly distributed along the circumferential direction of the grinding part of the grinding wheel.

[0018] Further, the shape and size of the cooling liquid groove are the same, and the shape of the cooling liquid groove includes straight line, curve or preset irregular line.

[0019] Further, the total length L of the grinding wheel, the total width d of the ultrasonic grinding head and the height h of the ultrasonic grinding head are determined by the longitudinal vibration principle of variable cross-section rod and the vibration distribution characteristics of ultrasonic vibration nodes and antinodes, the position corresponding to the central axis of the grinding wheel, the position corresponding to the antinode of the transverse edge of the ultrasonic grinding head, and the radius of the ultrasonic grinding head is an integer multiple of 1 / 2 wavelength; the position corresponding to the antinode of the longitudinal upper edge and lower edge of the ultrasonic grinding head, and the height of the ultrasonic grinding head is an integer multiple of 1 / 2 wavelength; the position corresponding to the node of the upper edge of the ultrasonic grinding wheel base rod, and the position corresponding to the antinode of the lower edge, and the length of the ultrasonic grinding wheel base rod is an integer multiple of 1 / 2 wavelength plus 1 / 4 wavelength.

[0020] Compared with the prior art, the present application has the following advantages:

[0021] 1. The cooling liquid main flow channel obtains cooling liquid through the machine tool, the cooling liquid first passes through the grinding wheel base and the ultrasonic grinding head, effectively reducing the temperature of the grinding wheel, and then is sprayed from the surface of the grinding part of the grinding wheel through the grinding head cooling liquid flow channel under the action of pressure and grinding wheel rotation to the grinding processing area, cooling, lubricating and flushing the grinding processing area, which can effectively reduce the grinding temperature, improve the surface quality and grinding processing performance. In addition, the effective use of cooling liquid can also play a role in lubricating the grinding processing area, reducing the friction of the grinding processing area and reducing the generation of grinding heat.

[0022] 2. This invention utilizes internal cooling. By providing a coolant main channel within the grinding wheel base and embedding a variable-diameter sleeve within the ultrasonic grinding wheel base rod, different variable-diameter schemes can be designed according to processing needs. The design diameter gradually decreases during acceleration and gradually increases during deceleration. A smooth transition scheme can also be designed. The design of the built-in variable-diameter sleeve is relatively flexible and can meet different processing requirements.

[0023] 3. Design an ultrasonic cavitation chamber in the inner cavity of the sleeve, and utilize the ultrasonic cavitation effect. In the low-pressure reaction chamber, when the ultrasonic energy is high enough, the tiny bubbles in the coolant vibrate, expand and continuously accumulate energy under the action of the ultrasonic field. In places with higher pressure, the cavitation bubbles collapse and explode rapidly, forming a strong impact force and micro-jets, and the grinding debris will reduce the surface quality of the workpiece.

[0024] 4. Designing rifling can increase the overall flow rate and enhance the cooling effect. The pitch and number of rifling lines can also be used to control the coolant utilization rate and flow rate, allowing for better control of coolant usage during processing. Local rifling can also be machined where you want to accelerate, providing more flexible coolant usage compared to existing methods.

[0025] 5. The lower end face structure of the grinding wheel can grind traditional flat surfaces, the side face structure can grind the inner wall of the workpiece hole, and the upper end face structure can grind the upper wall of some workpiece grooves. This invention can solve the cooling and temperature control problems of the grinding wheel for multiple uses.

[0026] 6. The surface of the grinding wheel is treated with hydrophilicity, which further improves the cooling efficiency based on the existing machine tool processing.

[0027] 7. The present invention provides a new calculation method for the tool size used in ultrasonic machining, which solves the drawback of the current grinding wheel selection based on experience. It applies scientific design such as nodes and antinodes, so that the positions where the amplitude needs to be enhanced correspond to the antinodes, and the positions where the interference needs to be reduced correspond to the nodes, thereby increasing the machining amplitude and achieving the gain effect of ultrasonic-assisted machining.

[0028] In summary, the present invention can design a grinding wheel size unique to ultrasound, can directly cool the inside of the grinding wheel in the grinding working state, and can also directly cool, lubricate and flush the inside of the grinding wheel and the grinding processing area. The cooling effect and speed of the coolant can be adjusted, and the ultrasonic cavitation effect can be used to prevent the coolant from being blocked. While reducing the influence of the air barrier effect, it also improves the cooling effect and improves the grinding processability. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] 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 or the description of the prior art. Obviously, the drawings described below are 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 labor.

[0030] Figure 1 It is a cross-sectional view of the overall structure in an embodiment of the present invention.

[0031] Figure 2 Schematic diagram of the overall structure of an embodiment of the present invention.

[0032] Figure 3 2 is a cross-sectional view of various reducer sleeves in an embodiment of the present invention.

[0033] Figure 4 2 is a cross-sectional view of the ultrasonic cavitation chamber structure in an embodiment of the present invention.

[0034] Figure 5 It is a cross-sectional view of the rifling structure in an embodiment of the present invention.

[0035] Figure 6 2 are cross-sectional views of the cooling liquid flow channel at different angles in an embodiment of the present invention.

[0036] Figure 7 It is a cross-sectional view of the grinding wheel size in an embodiment of the present invention.

[0037] Figure: 1. Ultrasonic grinding wheel base, 2. Sleeve, 3. Coolant main channel, 4. Ultrasonic grinding wheel grinding head, 5. Grinding head coolant channel, 6. Grinding head rifling, 7. Hexagonal groove, 8. Abrasive grain, 9. Coolant tank, 10. Threaded connection, 11. Acceleration step-reducing main channel, 12. Deceleration step-reducing main channel, 13. Arc-shaped reducing main channel, 14. Main channel rifling, 15. Ultrasonic cavitation chamber, 16. Coolant main channel outlet, 17. Grinding head coolant channel inlet, 18. Upper end face structure, 19. Lower end face structure, 20. Side face structure. DETAILED DESCRIPTION

[0038] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments of the present invention can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0039] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is in no way intended to limit the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0040] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or combinations thereof.

[0041] Unless otherwise specifically stated, the relative arrangement of the parts and steps, numerical expressions and numerical values ​​described in these embodiments do not limit the scope of the present invention. At the same time, it should be clear that, for ease of description, the sizes of the various parts shown in the drawings are not drawn according to the actual proportional relationship. The techniques, methods and equipment known to ordinary technicians in the relevant fields may not be discussed in detail, but where appropriate, the techniques, methods and equipment should be considered as part of the authorization specification. In all examples shown and discussed here, any specific value should be interpreted as merely exemplary and not as a limitation. Therefore, other examples of the exemplary embodiments may have different values. It should be noted that similar numbers and letters represent similar items in the following figures, so once an item is defined in one figure, it does not need to be further discussed in subsequent figures.

[0042] In the description of the present invention, it should be understood that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "horizontal, vertical, vertical, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the device or element referred to must have a specific direction or be constructed and operated in a specific direction. Therefore, they cannot be understood as limiting the scope of protection of the present invention: the directional words "inside and outside" refer to the inside and outside relative to the outline of each component itself.

[0043] For ease of description, spatially relative terms such as "above," "above," "on the upper surface of," and "above" may be used herein to describe the spatial positional relationship of a device or feature to other devices or features as shown in the figures. It should be understood that spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is inverted, a device described as "above" or "on top of" another device or structure would then be positioned as "below" or "below" the other device or structure. Thus, the exemplary term "above" may include both the orientations of "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used herein should be interpreted accordingly.

[0044] In addition, it should be noted that the use of terms such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore cannot be understood as limiting the scope of protection of the present invention.

[0045] like Figure 1 As shown, an embodiment of the present invention discloses a high-efficiency cooling grinding wheel for ultrasonic machining, comprising an upper ultrasonic grinding wheel base rod 1 and a lower ultrasonic grinding wheel grinding head 4. The upper end of the ultrasonic grinding wheel base rod is connected to the spindle of a grinding machine with internal cooling, and the machine body is connected to an ultrasonic tool holder through the spindle. The ultrasonic tool holder also receives the electrical signal emitted by the ultrasonic generator. This ultrasonic machining technology is a conventional technology in the prior art, that is, the technology mentioned in the background technology.

[0046] The ultrasonic grinding wheel base rod and the ultrasonic grinding wheel grinding head are an integrated structure; a coaxial hole is provided inside the ultrasonic grinding wheel base rod and extends to the bottom of the ultrasonic grinding wheel grinding head but does not penetrate through it. A sleeve 2 is connected to the ultrasonic grinding wheel base rod using an interference fit or threaded connection. The interior of the sleeve is a hollow structure with a preset inner diameter, which serves as a main coolant channel 3; a number of circular holes are evenly distributed inside the ultrasonic grinding wheel grinding head as a grinding head coolant channel 5, the inlet of the grinding head coolant channel is connected to the end of the main coolant channel, and the outlet of the grinding head coolant channel is located at the grinding processing position. A coolant tank 9 is machined at the outlet of the grinding head coolant channel; the inner cavity of the main coolant channel and the grinding head coolant channel is provided with a grinding head rifling 6. In this embodiment, the number of circular holes is 3-6.

[0047] The existing cooling mode of the external slot of the grinding wheel cannot accurately control the cooling surface. Therefore, in the embodiment of the present invention, the internal part of the grinding wheel is cooled, and the position and number of the coolant holes and the coolant grooves can be changed. The coolant flow channel of the grinding head forms a certain angle with the main coolant channel. According to the different angles, they are divided into upper end face structure, lower end face structure, and side face structure.

[0048] The inlet of the cooling liquid flow channel of the upper end surface type grinding head is connected to the bottom end of the cooling liquid main channel, and the outlet of the cooling liquid flow channel of the grinding head is arranged on the upper end surface of the grinding wheel grinding part;

[0049] The inlet of the cooling liquid flow channel of the grinding head of the lower end surface type structure is connected to the bottom end of the cooling liquid main channel, and the outlet of the cooling liquid flow channel of the grinding head is arranged on the lower end surface of the grinding wheel grinding part;

[0050] The inlet of the cooling liquid flow channel of the grinding head with the side structure is connected to the bottom end of the cooling liquid main channel, and the outlet of the cooling liquid flow channel of the grinding head is arranged on the side of the grinding wheel grinding part.

[0051] The present invention can accurately cool the processing position and improve the utilization rate of the coolant.

[0052] Specifically, if Figure 6 As shown, the input ends of the cooling liquid flow channels of the grinding heads are connected to the cooling liquid main flow channels, and the cooling liquid flow channel outlets all have cooling liquid grooves arranged along the side of the grinding wheel grinding part. The cooling liquid flow channels of the grinding heads form angles in three directions with the cooling liquid main flow channels, and are divided into upper end face structure 18, lower end face structure 19, and side face structure 20 according to the different angles formed. The outlet of the cooling liquid flow channel of the grinding head of the upper end face structure 18 is arranged on the upper end face of the grinding wheel grinding part, with an angle of 45 degrees. The outlet of the cooling liquid flow channel of the grinding head of the lower end face structure 19 is arranged on the lower end face of the grinding wheel grinding part, with an angle of 45 degrees. The outlet of the cooling liquid flow channel of the grinding head of the side face structure 20 is arranged on the side of the grinding wheel grinding part, with an angle of 90 degrees. The shapes and sizes of the cooling liquid flow channels of the grinding heads are the same, and the angle formed by each cooling liquid flow channel of the grinding heads and the cooling liquid main flow channel is the same. The cooling liquid flow channels of the grinding heads are evenly distributed along the circumferential direction of the grinding wheel grinding part, which facilitates the processing of the cooling liquid flow channels. The shapes and sizes of the cooling liquid tanks 9 are the same, and the shapes of the cooling liquid tanks include straight lines, curves, or preset irregular lines.

[0053] As mentioned above, the interior of the sleeve is a hollow structure with a preset inner diameter, and the hollow structure with a preset inner diameter can be a constant diameter structure.

[0054] As a preferred embodiment, the diameter of the hollow structure inside the sleeve can be changed, specifically including a step-type diameter change and an arc-shaped diameter change, that is, a diameter-changing structure, as a diameter-changing sleeve. Specifically, as Figure 3As shown, a reducing sleeve with a variable inner diameter is nested in the ultrasonic grinding wheel base rod 1. The internal design of the reducing sleeve is diverse, including different forms such as the accelerating step reducing main channel 11, the decelerating step reducing main channel 12 and the arc reducing main channel 13, so as to realize the acceleration and deceleration of the coolant and irregular speed change. The reducing sleeve can be made of plastic material and is nested in the inner wall of the ultrasonic grinding wheel base rod at low temperature. At room temperature, the reducing sleeve and the ultrasonic grinding wheel base rod form an interference fit. Or as Figure 2 As shown, the reducer sleeve can also be processed using metal materials, with an external thread processed at the upper end outlet of the reducer sleeve and an internal thread processed at the upper end outlet of the ultrasonic grinding wheel base rod. A threaded connection 10 is used between the ultrasonic grinding wheel base rod and the reducer sleeve, and a hexagonal groove 7 is processed at the upper end outlet of the reducer sleeve. The reducer sleeve can be installed using a hexagonal wrench. The above-mentioned acceleration step-diameter reduction type is specifically that the diameter of the reducer sleeve from the upper end of the ultrasonic grinding wheel base rod to the ultrasonic grinding wheel grinding head gradually decreases and changes in a step-like manner. The above-mentioned deceleration step-diameter reduction type is specifically that the diameter of the reducer sleeve from the upper end of the ultrasonic grinding wheel base rod to the ultrasonic grinding wheel grinding head gradually increases and changes in a step-like manner. The irregular speed change can be the arc-shaped speed change shown in the figure, that is, the diameter of the reducer sleeve from the upper end of the ultrasonic grinding wheel base rod to the ultrasonic grinding wheel grinding head changes from small to large, and the interior of the sleeve presents a smooth arc-shaped transition.

[0055] Furthermore, a cavity is provided at the lower end of the reducing sleeve as an ultrasonic cavitation chamber. Specifically, Figure 4 As shown, an ultrasonic cavitation sleeve structure suitable for ultrasonic assisted machining is designed in the reducer sleeve. The diameter of the upper end of the reducer sleeve and the coolant flow channel of the grinding head is small, and the inner wall is processed with main channel rifling 14, which is in a high-pressure and high-flow rate environment. The cavity at the lower end of the reducer sleeve serves as the ultrasonic cavitation action chamber 15 and is in a low-pressure environment. The tiny bubble nuclei in the liquid vibrate under the action of ultrasound. When the pressure reaches a certain value, the bubbles will expand rapidly and then suddenly close, generating shock waves when the bubbles close. This expansion, closing, oscillation and other series of dynamic processes. The role of the ultrasonic cavitation reaction is to form a strong impact force and micro-jet. During the grinding process, the workpiece and chips may block the outflow of coolant. This design can wash away the processing debris in time to prevent it from affecting the surface quality, avoid clogging of the grinding wheel and take away the chips in time to improve the grinding quality.

[0056] Specifically, the ultrasonic tool handle converts high-frequency electrical signals into mechanical vibrations of ultrasonic frequency through a built-in ultrasonic transducer, and then amplifies the vibration amplitude through the amplitude transformer and transmits it to the grinding wheel.

[0057] When ultrasonic vibrations are transmitted through the ultrasonic grinding wheel base rod to the coolant in the cavitation chamber within the wheel base rod, the ultrasonic waves propagate as longitudinal waves, causing the liquid particles to alternate between dense and rarefied states during propagation. In the rarefied state, the liquid particles experience tension. When the tension exceeds the static pressure of the liquid, vacuum cavities, or bubbles, form within the liquid. These bubbles undergo periodic oscillations under the influence of ultrasonic waves. During the rarefied portion of the sound wave, the bubbles expand and during the dense portion, they contract. As the ultrasonic wave intensity increases, the bubble oscillation amplitude gradually increases. When the ultrasonic wave energy reaches a sufficiently high level, the bubble oscillations become extremely intense. At this point, the bubble's vibrations are controlled by the inertia of the surrounding medium, causing it to rapidly expand during the negative pressure half-cycle of the sound wave and contract sharply during the positive pressure half-cycle, ultimately leading to the bubble's rupture. When the bubble ruptures, the gas inside rapidly diffuses into the surrounding liquid, generating high pressure and a strong shock wave. These high-pressure shock waves produce a series of physical effects on the surrounding area, generating liquid microjets with speeds of hundreds of meters per second, which impact the processing position and carry away the chips.

[0058] The upper end of the reducer and the coolant flow path of the grinding head have a small diameter and are machined with rifling on the inner wall, creating a high-pressure, high-flow environment. The cavity at the lower end of the reducer acts as the ultrasonic cavitation chamber, a low-pressure environment. The ultrasonic cavitation reaction creates a powerful impact force and micro-jets, which quickly remove fine grinding debris and prevent it from adhering to the processing area and degrading the workpiece surface quality.

[0059] like Figure 5 As shown, rifling is added to the inner wall of the coolant main channel and the coolant channel of the grinding head. Furthermore, the rifling direction and angle of the coolant main channel are the same as those of the coolant channel of the grinding head. The rifling types include uniform rifling, gradual rifling, mixed rifling, constant width rifling, and wedge rifling. The rifling allows the coolant to rotate around the inner wall and fully contact the inside of the grinding wheel, avoiding uneven heat dissipation when the coolant flows along one side and improving the internal cooling effect. The pitch of the rifling is used to adjust the coolant flow rate. The larger the pitch, the faster the flow rate, and the smaller the pitch, the smaller the flow rate. The number of rifling is used to adjust the cooling effect. The more rifling, the better the cooling effect. This example adopts a design with a 25 pitch and four rifling. The coolant main channel outlet 16 in the reducer corresponds to the grinding head coolant channel inlet 17 and has the same rotation direction to ensure that the coolant flow rate is inherited. The rifling structure is machined into the main channel and the grinding head coolant channel. The rifling processing methods include scraping, hook knife broaching and cold extrusion.

[0060] Furthermore, the cross-section of the cooling liquid flow channel of the grinding head is circular, and the diameter does not exceed 1 / 3 of the thickness of the ultrasonic grinding wheel grinding head. The shape and size of the cooling liquid tank are the same, and the shape of the cooling liquid tank includes a straight line, a curve or a preset irregular line.

[0061] Furthermore, the abrasive grains of the grinding wheel are processed with a hydrophilic surface using electroplating, coating, or ion implantation, resulting in a hydrophilic surface for the grinding wheel and the abrasive grains. After the electroplating process, the grinding wheel wears out, releasing new abrasive grains. These can then be treated with a hydrophilic treatment twice or more to ensure hydrophilicity. This hydrophilic treatment allows more coolant to remain between the abrasive grains of the grinding wheel, resulting in more efficient cooling during the grinding process.

[0062] Furthermore, the circular holes have the same shape and size, and the angle formed by each circular hole and the coolant main channel is the same. The circular holes are evenly distributed along the circumferential direction of the grinding part of the grinding wheel.

[0063] Furthermore, the shapes and sizes of the cooling liquid tanks are all the same, and the shapes of the cooling liquid tanks include straight lines, curves, or preset irregular lines. The specific opening size of the present invention can be adjusted and designed according to the temperature control requirements, and the provision of a main cutting fluid flow channel can ensure that the cutting fluid fully enters the cutting hole, ensuring the cooling effect. This solves the problem of the prior art patents that the opening processing is difficult, the opening is too small, and when the grinding wheel is running at high speed, very little cutting fluid enters the hole due to the air barrier effect, resulting in limited cooling effect.

[0064] like Figure 7 As shown in the figure, standing wave curves are generated during ultrasonic machining. Transverse ultrasound and longitudinal ultrasound can respectively use the nodes and antinodes in the standing wave curves to determine the optimal size of the grinding wheel and maximize the ultrasonic gain. The interference minimum characteristics of the nodes and the interference maximum characteristics of the antinodes are used to determine the total length L of the grinding wheel, the total width d of the ultrasonic grinding wheel grinding head, and the height h of the ultrasonic grinding wheel grinding head.

[0065] The center axis of the grinding wheel corresponds to the position of the wave node, the transverse edge of the ultrasonic grinding wheel grinding head corresponds to the position of the wave antinode, and the radius of the ultrasonic grinding wheel grinding head is an integer multiple of 1 / 2 wavelength; the longitudinal upper edge and lower edge of the ultrasonic grinding wheel grinding head correspond to the position of the wave antinode, and the height of the ultrasonic grinding wheel grinding head is an integer multiple of 1 / 2 wavelength; the upper edge of the ultrasonic grinding wheel base rod corresponds to the position of the wave node, the lower edge corresponds to the position of the wave antinode, and the length of the ultrasonic grinding wheel base rod is an integer multiple of 1 / 2 wavelength plus 1 / 4 wavelength.

[0066] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements 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. A high-efficiency cooling grinding wheel for ultrasonic machining, characterized in that: The ultrasonic grinding wheel base rod comprises an upper ultrasonic grinding wheel base rod and a lower ultrasonic grinding wheel grinding head, wherein the ultrasonic grinding wheel base rod and the ultrasonic grinding wheel grinding head are an integrated structure; a coaxial hole is arranged inside the ultrasonic grinding wheel base rod and extends to the bottom of the ultrasonic grinding wheel grinding head but does not penetrate through the ultrasonic grinding wheel base rod; a sleeve is provided inside the ultrasonic grinding wheel base rod using a threaded connection or interference fit, and the interior of the sleeve is a hollow structure with a preset inner diameter, which serves as a main coolant channel; a plurality of circular holes are uniformly distributed inside the ultrasonic grinding wheel grinding head as coolant channels for the grinding head, the inlet of the coolant channel for the grinding head is connected to the end of the coolant main channel, the outlet of the coolant channel for the grinding head is located at the grinding processing position, and a coolant tank is processed at the outlet of the coolant channel for the grinding head; the coolant main channel and the inner cavity of the coolant channel for the grinding head are arranged Rifling structure; a sleeve nested in the ultrasonic grinding wheel base rod is designed with different diameter reduction schemes according to processing requirements; the total length L of the grinding wheel, the total width d of the ultrasonic grinding wheel grinding head and the height h of the ultrasonic grinding wheel grinding head are determined by applying the longitudinal vibration principle of the variable-section rod and the vibration distribution characteristics of the ultrasonic vibration nodes and antinodes, the corresponding position of the grinding wheel center axis, the transverse edge of the ultrasonic grinding wheel grinding head corresponds to the antinode position, and the radius of the ultrasonic grinding wheel grinding head is an integer multiple of 1 / 2 wavelength; the longitudinal upper and lower edges of the ultrasonic grinding wheel grinding head correspond to the antinode position, and the height of the ultrasonic grinding wheel grinding head is an integer multiple of 1 / 2 wavelength; the upper edge of the ultrasonic grinding wheel base rod corresponds to the node position, the lower edge corresponds to the antinode position, and the length of the ultrasonic grinding wheel base rod is an integer multiple of 1 / 2 wavelength plus 1 / 4 wavelength.

2. The high-efficiency cooling grinding wheel for ultrasonic machining according to claim 1, characterized in that: A cavity is provided at the lower end of the sleeve, serving as an ultrasonic cavitation chamber.

3. The high-efficiency cooling grinding wheel for ultrasonic machining according to claim 1, characterized in that: The cooling liquid flow channel of the grinding head forms a certain angle with the main cooling liquid flow channel, and is divided into upper end face structure, lower end face structure and side face structure according to the different angles. The inlet of the cooling liquid flow channel of the upper end surface type grinding head is connected to the bottom end of the cooling liquid main channel, and the outlet of the cooling liquid flow channel of the grinding head is arranged on the upper end surface of the grinding wheel grinding part; The inlet of the cooling liquid flow channel of the grinding head of the lower end surface type structure is connected to the bottom end of the cooling liquid main channel, and the outlet of the cooling liquid flow channel of the grinding head is arranged on the lower end surface of the grinding wheel grinding part; The inlet of the cooling liquid flow channel of the grinding head with the side structure is connected to the bottom end of the cooling liquid main channel, and the outlet of the cooling liquid flow channel of the grinding head is arranged on the side of the grinding wheel grinding part.

4. The high-efficiency cooling grinding wheel for ultrasonic machining according to claim 1, characterized in that: The diameter of the hollow structure inside the sleeve can be changed, specifically including a step-diameter reducing type and an arc-shaped diameter reducing type.

5. The high-efficiency cooling grinding wheel for ultrasonic machining according to claim 1, characterized in that: The rifling rotation direction and angle of the coolant main channel are the same as those of the coolant flow channel of the grinding head. The rifling types include uniform rifling, gradual rifling, mixed rifling, constant width rifling and wedge rifling.

6. The high-efficiency cooling grinding wheel for ultrasonic machining according to claim 1, characterized in that: The cross section of the grinding head coolant flow channel is circular, and the diameter does not exceed 1 / 3 of the thickness of the ultrasonic grinding wheel grinding head. The shape and size of the coolant tank are the same, and the shape of the coolant tank includes a straight line, a curve or a preset irregular line.

7. The high-efficiency cooling grinding wheel for ultrasonic machining according to claim 1, characterized in that: The outside of the grinding wheel is processed into a hydrophilic grinding wheel surface by electroplating process, coating process or ion implantation, and both the grinding wheel surface and the abrasive grains are hydrophilic.

8. The high-efficiency cooling grinding wheel for ultrasonic machining according to claim 1, characterized in that: The circular holes have the same shape and size, and the angle formed by each circular hole and the coolant main channel is the same. The circular holes are evenly distributed along the circumferential direction of the grinding part of the grinding wheel.

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