WO2020093418A1

WO2020093418A1 - Shrink-fit giant magnetostrictive ultrasonic tool holder

Info

Publication number: WO2020093418A1
Application number: PCT/CN2018/115001
Authority: WO
Inventors: 张建富; 冯平法; 周辉林; 郁鼎文; 吴志军
Original assignee: 清华大学
Priority date: 2018-11-05
Filing date: 2018-11-12
Publication date: 2020-05-14
Also published as: CN109109173B; CN109109173A

Abstract

A shrink-fit giant magnetostrictive ultrasonic tool holder, comprising: a holder housing (1) provided with a first central hole (10); a transducer provided in the first central hole (10) and in clearance fit with the inner wall of the holder housing (1); a horn (3) made out of magnetic conductive stainless steel, the horn (3) being connected to the transducer, the end face of the horn (3) contacting the transducer being provided on a plane having the maximum amplitude of vibration, the horn (3) being provided with a conical structure (32) on a plane having a minimum amplitude, the holder housing (1) being correspondingly provided with a conical hole (11) matching the conical structure, the conical structure (32) of the horn (3) being pressed against the conical hole (11), and a tool mounting hole (34) being provided at the central position of the end of the horn (3) away from the transducer; and a tool (4) made out of a hard alloy and tightly fixed in the tool mounting hole (34) in shrink-fit fashion. The conical fixation structures of the horn (3) and the holder housing (1) on a nodal plane ensure the axiality of mounting and ensure that a pretension state of an ultrasonic vibrator is not influenced by load impacts, thereby improving the load resistance capability of a giant magnetostrictive ultrasonic machining system.

Description

Hot-mounted super magnetostrictive ultrasonic tool handle

Technical field

The invention relates to the technical field of precision machining, and more specifically, to a hot-mounted super magnetostrictive ultrasonic tool holder.

Background technique

According to a large number of theoretical and experimental studies, ultrasonic machining is an effective method for processing brittle and hard materials, and giant magnetostrictive materials have the advantages of large energy density, high stability, and good thermal conductivity. Sexual ultrasonic processing is possible. Ultrasonic processing can effectively improve the processing efficiency and processing quality. It has been widely used in the development of rotary ultrasonic processing systems, but for the stability of ultrasonic processing, there are still many problems to be solved urgently.

During the ultrasonic processing of difficult-to-machine materials, if the structure of the ultrasonic tool holder is improperly designed, the workpiece load will not only affect the system resonance state, but also affect the prestressed state of the ultrasonic vibrator through the reaction force of the load, which directly leads to the system resistance The load capacity is reduced and the ultrasound is suppressed; at the same time, the coaxiality installation of the ultrasonic tool holder will also greatly affect the machining accuracy.

Summary of the invention

In view of the above problems, an object of the present invention is to provide a hot-mounted super magnetostrictive ultrasonic tool holder to solve the problem of improper design of the ultrasonic tool holder in the prior art that affects processing accuracy.

In order to achieve the above objectives, the present invention is achieved by the following technical solutions:

A hot-mounted super magnetostrictive ultrasonic tool holder, the ultrasonic retractable tool holder includes:

The tool holder housing is provided with a first central hole;

A transducer, which is arranged in the first central hole and clearance-matched with the inner wall of the tool holder housing;

A horn, made of magnetically permeable stainless steel, the horn is arranged in the first central hole and the horn is in clearance fit with the inner wall of the first central hole, one end of the horn Connected to the transducer, the end face of the horn that is in contact with the transducer is set at the maximum amplitude surface of the transducer that generates vibration, and the horn is produced by the transducer A cone surface structure is provided at the minimum amplitude surface of vibration, and the tool holder housing is correspondingly provided with a tapered hole matching the cone surface structure at the minimum amplitude surface, and the cone surface structure of the horn Pressing in the tapered hole so that the horn and the holder housing are in contact and connected here, the tapered hole communicates with the first central hole, the other of the horn A tool mounting hole is provided at the center of one end; and

The cutter is made of cemented carbide material, and the cutter is hot-installed and fastened in the cutter installation hole.

Further, the tool holder housing further has a second center hole, the second center hole is disposed on an end side of the tapered hole away from the first center hole, and the ultrasonic telescopic tool holder further includes a lock A pressing block, the locking pressing block has an axial through hole, and the axial through hole of the locking pressing block passes through the other end of the horn and is fixed in the second central hole and is The end face of the locking pressing block close to the transducer abuts the horn to lock the horn in the tool holder housing.

Further, the inner wall of the axial through hole is not in contact with the horn.

Further, the radial end surface of the locking pressing block does not contact the radial end surface of the tool holder housing.

Further, the locking pressure block and the tool holder housing are connected by a thread, and the rotation direction of the thread is consistent with the turning direction of the machine tool spindle.

Further, the transducer includes:

A pre-tightening pressure block, which is arranged in the first central hole and does not contact the inner wall of the tool holder housing;

A vibrating body, which includes an ultrasonic vibrator and an excitation structure sheathed outside the ultrasonic vibrator, and an end surface of one end of the ultrasonic vibrator abuts against an end surface of the pretensioning pressing block close to the horn; and

The output sleeve includes a cylindrical body and a connecting body provided at the central position of the cylindrical body, the cylindrical body extends in the direction of the pre-tensioned pressure block and is connected to the pre-tensioned pressure block by fasteners, The vibrating body is accommodated in the cylindrical body, the end face of the connecting body away from the pre-tensioning pressure block abuts the end face of the horn near the pre-tensioning pressure block, and the connecting body is The end surface contacted by the horn is set on the maximum amplitude surface.

Further, a first stepped surface that cooperates with an end of the ultrasonic vibrator away from the preload pressure block is provided on a center position of the end surface of the connecting body close to the preload pressure block. The ultrasonic vibrator and the first step surface A step surface abuts.

Further, an extension part extending toward the horn is also provided on the connecting body, and a second step cooperating with the extension part is provided at a center position of an end of the horn close to the pre-tensioning pressing block Surface, the extension portion and the second stepped surface are connected by screws.

Further, neither the end surface in the radial direction of the extension portion nor the end surface in the radial direction of the second step surface is in contact.

Further, the horn includes a rod body, a connecting piece provided on the outer peripheral wall of the rod body, and a tapered cylinder provided on the connecting piece and extending toward the direction of the transducer, the outer periphery of the tapered cylinder The surface is in contact connection with the tapered hole.

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

1. The present invention fully considers the force transmission characteristics of the giant magnetostrictive material under load during processing, and designs the nodal conical connection structure of the horn to ensure that the prestressed state of the ultrasonic vibrator is not affected by the load impact and improve the giant magnetostriction Ultrasonic processing load resistance and assembly effect;

2. The conical surface positioning structure of the horn designed by the present invention and the second stepped surface connected to the output sleeve both ensure the coaxiality in the ultrasonic processing, reduce the influence of the coaxiality of the combined face, and improve Installation accuracy and assembly efficiency;

3. The contact surface between the horn and the transducer is set at the maximum output amplitude surface, which improves the output efficiency of vibration;

4. In the present invention, the ultrasonic machining process of multiple tools can be studied without disassembling other structures, which improves the efficiency of ultrasonic tool replacement and improves the research conditions of ultrasonic machining process;

5. Since the super magnetostrictive ultrasonic tool holder of the present invention adopts an integrated and fully enclosed design appearance, the structure is compact, and the core components of the device are effectively prevented from being damaged by dust and particles during processing;

6. The model established by the present invention can further explore the influence of the load on the ultrasonic processing by changing the process parameters, and can be used in experiments that explore the resistance of different ultrasonic processing processes to the load.

In order to achieve the above and related objects, one or more aspects of the present invention include the features specifically pointed out in the following detailed description. The following description and the drawings illustrate certain exemplary aspects of the invention in detail. However, these aspects indicate only some of the various ways in which the principles of the invention can be used. Furthermore, the invention is intended to include all these aspects and their equivalents.

BRIEF DESCRIPTION

By referring to the following description in conjunction with the drawings, and with a more comprehensive understanding of the present invention, other objects and results of the present invention will be more clear and easy to understand. In the drawings:

FIG. 1 is a schematic structural view of a hot-mounted super magnetostrictive ultrasonic tool holder according to an embodiment of the present invention;

2 is a front cross-sectional view of a hot-mounted super magnetostrictive ultrasonic tool holder according to an embodiment of the present invention;

3 is a full cross-sectional front view of an output sleeve according to an embodiment of the present invention;

4 is a front view of a full section of a horn according to an embodiment of the present invention;

5 is a schematic diagram of the size design of a transducer according to an embodiment of the present invention.

The same reference numbers indicate similar or corresponding features or functions in all drawings.

detailed description

The specific embodiments of the present invention will be described in detail below with reference to the drawings.

It should be noted that in the description of the present invention, the terms "horizontal", "vertical", "upper", "lower", "front", "back", "left", "right", "vertical", The azimuth or positional relationship indicated by "horizontal", "top", "bottom", "inner", "outer", etc. is based on the azimuth or positional relationship shown in the drawings, only for the convenience of describing the invention and simplifying the description, It does not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be construed as limiting the present invention.

As shown in FIGS. 1-4, the present invention provides a hot-mounted super magnetostrictive ultrasonic tool holder, which mainly includes a tool holder housing 1, a transducer, a horn 3, and a tool 4. The tool holder housing 1 is a hollow housing, and a first central hole 10 is provided therein. The transducer is accommodated in the first central hole 10 and it is in clearance fit with the inner wall of the holder housing 1. The transducer includes a pre-tensioned pressure block 20, a vibrating body 21, and an output sleeve 22. The pre-tightening pressure block 20 is disposed in the first central hole 10 and does not contact the inner wall of the tool holder housing 1, thereby eliminating its influence on the pre-tightening state of the vibrating body 21. In a specific embodiment of the present invention, the pre-tensioned pressing block 20 includes a first cylinder 201, a second cylinder 202 and a third cylinder 203 connected in sequence, wherein the first cylinder 201, the second cylinder 202 and The diameter of the third cylinder 203 gradually decreases; of course, the pre-tensioning pressure block 20 can also be other structures that facilitate pre-tensioning and connection. The vibrating body 21 includes an ultrasonic vibrator 210 and an excitation structure 211 sheathed outside the ultrasonic vibrator 210. The excitation structure 211 provides the ultrasonic vibrator 210 with an ultrasonic frequency alternating magnetic field, thereby generating ultrasonic frequency mechanical vibration. The lower end surface of the third cylinder on the pretensioning pressure block 20 abuts on the upper end surface of the ultrasonic vibrator 210, thereby pretensioning the ultrasonic vibrator 210. The output sleeve 22 is also disposed in the first central hole 10 and does not contact the inner wall of the tool holder housing 1 to prevent the ultrasonic vibrator 210 from being impacted by a load during processing. In order to facilitate the connection, the output sleeve 22 includes a cylindrical body 220 and a connecting body 221 provided at the central position of the cylindrical body 220. The cylindrical body 220 extends toward the direction of the preloading block 20, and the upper end surface of the cylindrical body 220 is fixedly connected to the first cylinder 200 on the preloading block 20 along the circumferential direction by a plurality of screws. The outer peripheral surface of the second cylinder 201 is in contact connection. Both ends of the connecting body 221 are respectively connected to the ultrasonic vibrator 210 and the horn 3, wherein the first step surface (not shown in the figure) of the upper end surface of the connecting body 221 is provided at the center of the lower end of the ultrasonic vibrator 210 ), The lower end surface of the ultrasonic vibrator 210 is in contact with the first step surface of the connecting body 221 to centrally position the ultrasonic vibrator 210, thereby ensuring the coaxiality of the two and preventing the deviation from affecting the work during the working process effect. So far, the vibrating body 21 is wrapped in the cylindrical body 220 of the output sleeve 22, which can prevent other external substances from affecting the work of the vibrating body.

The horn 3 is made of magnetically conductive stainless steel material. The stainless steel material has good rust resistance. After multiple sintering, the surface is not easy to fall off and will not affect the accuracy. And because it has magnetic permeability, it is convenient for non-contact electromagnetic induction heating. Therefore, it is convenient for the tool 4 to be hot-mounted and fastened on it. The horn 3 is disposed in the first central hole 10 and its lower end protrudes from the shank housing 1. The horn 3 is in clearance fit with the inner wall of the first central hole 10. The horn 3 includes a rod body 30, a connecting piece 31 provided on the outer peripheral wall of the rod body 30, and a tapered cylinder 32 provided on the upper end surface of the connecting piece 31 and extending toward the transducer. The upper end surface of the rod body 30 abuts the lower end surface of the connecting body 221 of the output sleeve 22; in order to make the vibration output more efficient, the contact surface between the upper end surface of the horn 3 and the lower end surface of the connecting body 221 is set at the output amplitude At the maximum surface. A second step surface 33 is provided at the center of the upper end surface of the horn 3, and correspondingly, an extension portion 222 is provided on the lower end surface of the connecting body 221, and the extension portion 222 is limited in the second step surface 33, so Can ensure the coaxiality of the two, improve the ultrasonic machining installation accuracy and assembly efficiency; in addition, in order to make the connection between the two more stable, the inner wall of the second step surface 33 is provided with a section of internal thread, the outer periphery of the extension 222 A section of external threads matching the internal threads is also provided on the surface so that the horn 3 and the extension 222 are connected by threads. The radial end surface of the extension portion 222 and the radial end surface of the second step surface 33 are not in contact, thereby preventing vibration from being attenuated during transmission.

The tool holder housing 1 is provided with a tapered hole 11 at the lower end of the first central hole 10. The position and shape of the tapered hole 11 correspond to the tapered cylinder 32 on the horn 3 so that the horn 3 The tapered cylinder 32 is just fastened in the tapered hole 11 so as to ensure the coaxiality of the horn 3 and the tool holder housing 1. In order to reduce the vibration attenuation caused by the contact connection, the contact surface of the tapered cylinder 32 and the tapered hole 11 is set at the output amplitude minimum surface (ie, the nodal surface), which also avoids the processing load on the ultrasonic vibrator 211 The pre-tightening state has a direct effect, which improves the load resistance of ultrasonic machining. The diameter of the tapered hole 11 gradually increases with distance from the transducer, so as to facilitate the processing of the tapered hole 11. The radial end face of the horn 3 does not contact with the radial end face of the tool holder housing 1 to avoid affecting the vibration transmission effect. A cutter mounting hole 34 is provided at the center of the lower end of the horn 3. The tool 4 needs to have a material with a small thermal expansion relative to the material used for the horn 3 and has a high hardness. Therefore, in the present invention, a hard alloy material is used for the tool 4. The tool 4 is fastened in the tool mounting hole 34 by hot fitting and protrudes from the tool holder housing 1. Due to the characteristics of the magnetically permeable stainless steel material, a variety of different tools 4 can be hot-installed in the tool mounting hole 34. The cutter 4 may be a sharp knife and disc cutter structure used for dry cutting of KDP or paper-based honeycomb materials, or a diamond grinding head, drill bit, milling cutter, etc. used for metal processing.

In another specific embodiment of the present invention, the locking pressing block 5 is further included, and the locking pressing block 5 has an axial through hole 50 at the center position. The tool holder housing 1 is also provided with a second central hole 12 which is provided at the lower end of the tapered hole 11. The axial through hole 50 of the locking pressing block 5 is disposed in the second center hole 12 through the lower end of the horn 3 and the upper end surface of the locking pressing block 5 abuts the lower end surface of the connecting piece 31, thereby changing the amplitude The tapered cylinder 32 of the rod 3 is locked in the tapered hole 11 of the tool holder housing 1, which further ensures the coaxiality of the horn 3 and the tool holder housing 1, thereby improving the installation accuracy. The locking pressing block 5 and the inner wall of the second central hole 12 are connected by a screw thread, and the rotation direction of the screw thread is consistent with the turning direction of the machine tool spindle to prevent the locking pressing block 5 from loosening during processing. The radial end face of the locking pressing block 5 after being fastened with the tool holder housing 1 does not contact the end face of the tool holder housing 1 in the radial direction, preventing vibration from being attenuated. In order to facilitate tightening or unscrewing the locking pressing block 5, an opening can be provided on the peripheral surface of the locking pressing block, so that the tool is inserted into the opening to screw the locking pressing block 5; or at the lower end of the locking pressing block 5 A small-diameter clamping block is provided to facilitate clamping by an adjustable wrench.

The size of the transducer of the present invention can be designed with reference to the following model:

As shown in FIG. 5, the transducer includes a pre-tensioned pressure block 20, an excitation structure 211, an ultrasonic vibrator 210, and an output sleeve 22. The preloading block 20, the ultrasonic vibrator 210, and the output sleeve 22 are equivalent to three equal cross-section cylinders in contact with each other.

k is the wave number, k = ω / c; c is the speed of sound wave propagation in the material, c = λf; ω is the angular frequency of the simple harmonic motion, ω = 2πf; λ is the wavelength of the sound wave in the material, f is the excitation frequency .

When designing with a part in the middle of the ultrasonic vibrator as the nodal plane, the frequency equation to the left of the nodal plane can be obtained:

Similarly, the frequency equation to the right of the nodal plane can be obtained:

Where Z _n represents the acoustic impedance, Z _n = ρ _n c _n S _n , ρ _n represents the density of the material, c _n represents the speed of sound wave propagation in the material, S _n represents the cross-sectional area; a, b, c, d represent The equivalent length of each part; k ₁ , k ₂ , k ₃ , and k ₄ represent the wave number.

According to the above-mentioned design structure, the end surface of the output sleeve 22 in contact with the hot-mounted horn 3 is the surface with the largest output amplitude. Similarly, the pitch size of the horn 3 can be designed with reference to the above model.

The heat-loaded super magnetostrictive ultrasonic tool holder according to the present invention is described by way of example with reference to the accompanying drawings. However, those skilled in the art should understand that, for the above-mentioned hot-mounted super magnetostrictive ultrasonic tool holder proposed by the present invention, various improvements can be made without departing from the content of the present invention. Therefore, the protection scope of the present invention should be determined by the contents of the appended claims.

Claims

A hot-mounted super magnetostrictive ultrasonic tool holder, characterized in that the ultrasonic telescopic tool holder includes:

The tool holder housing is provided with a first central hole;

A transducer, which is arranged in the first central hole and clearance-matched with the inner wall of the tool holder housing;

A horn, made of magnetically permeable stainless steel material, the horn is arranged in the first central hole and the horn is in clearance fit with the inner wall of the first center hole, the One end is connected to the transducer, and the end face of the horn in contact with the transducer is set at the maximum amplitude surface of the transducer to generate vibration, and the horn is located in the transducer A cone surface structure is provided at the minimum amplitude surface of vibration, the tool holder shell is correspondingly provided with a tapered hole matching the tapered surface structure at the minimum amplitude surface, and the cone surface of the horn The structure is compressed in the tapered hole so that the horn and the shank housing are in contact and connected there, the tapered hole communicates with the first central hole, the horn A tool mounting hole is provided at the center of the other end; and

The cutter is made of cemented carbide material, and the cutter is hot-installed and fastened in the cutter installation hole.
The hot-mounted super magnetostrictive ultrasonic tool holder according to claim 1, wherein the tool holder housing further has a second central hole, and the second central hole is disposed away from the tapered hole On the end side of the first central hole, the giant magnetostrictive ultrasonic tool holder further includes a locking pressing block, the locking pressing block has an axial through hole, and the axial through hole of the locking pressing block passes through After the other end of the horn is fixed in the second central hole and the end face of the locking clamp close to the transducer abuts against the horn to hold the horn Locked in the handle housing.
The hot-mounted super magnetostrictive ultrasonic tool holder according to claim 2, wherein the inner wall of the axial through hole does not contact the horn.
The hot-mounted super-magnetostrictive ultrasonic tool holder according to claim 2, characterized in that the radial end surface of the locking pressing block is not in contact with the radial end surface of the tool holder housing.
The hot-mounted super magnetostrictive ultrasonic tool holder according to claim 2, characterized in that the locking pressure block and the tool holder housing are connected by a thread, and the rotation direction of the thread is consistent with the turning direction of the machine tool spindle .
The hot-mounted super magnetostrictive ultrasonic tool holder according to claim 1, wherein the transducer comprises:

A pre-tightening pressure block, which is arranged in the first central hole and does not contact the inner wall of the tool holder housing;

A vibrating body, which includes an ultrasonic vibrator and an excitation structure sheathed outside the ultrasonic vibrator, and an end surface of one end of the ultrasonic vibrator abuts against an end surface of the pretensioning pressing block close to the horn; and

The output sleeve includes a cylindrical body and a connecting body provided at the central position of the cylindrical body, the cylindrical body extends in the direction of the pre-tensioned pressure block and is connected to the pre-tensioned pressure block by fasteners, The vibrating body is accommodated in the cylindrical body, the end face of the connecting body away from the pre-tensioning pressure block abuts the end face of the horn near the pre-tensioning pressure block, and the connecting body is The end surface contacted by the horn is set on the maximum amplitude surface.
The hot-mounted super-magnetostrictive ultrasonic tool holder according to claim 6, wherein the connecting body is provided at a center position of the end surface close to the pretensioning pressing block away from the ultrasonic vibrator to the pretensioning In the first step surface fitted at one end of the pressing block, the ultrasonic vibrator abuts on the first step surface.
The hot-mounted super magnetostrictive ultrasonic tool holder according to claim 6, wherein the connecting body is further provided with an extension portion extending toward the horn, and the horn is close to the pre-tensioning pressure The center of one end of the block is provided with a second stepped surface that cooperates with the extension portion, and the extension portion and the second stepped surface are connected by a screw.
The hot-mounted super magnetostrictive ultrasonic tool holder according to claim 8, wherein the radial end surface of the extension portion and the radial end surface of the second step surface are not in contact.
The hot-mounted super magnetostrictive ultrasonic tool holder according to claim 1, wherein the horn includes a rod body, a connecting piece provided on the outer peripheral wall of the rod body, and facing the connecting piece A tapered cylinder extending in the direction of the transducer, an outer circumferential surface of the tapered cylinder is in contact with the tapered hole.