JP2004001113A - Ultrasonic machining device and ultrasonic vibrator used for the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To machine a workpiece with excellent shape accuracy by suppressing vibration of a tool in the radial direction of a horn. <P>SOLUTION: The horn attached with the tool is formed so that a natural frequency of the radial stretching vibration mode or the axial bending vibration mode may be ≤0. 90 times or ≥1. 10 times as many as the natural frequency of the axial stretching vibration mode in degree used for ultrasonic machining, preferably ≤0. 85 times or ≥1. 15 times. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an ultrasonic processing device and an ultrasonic vibrator used for the ultrasonic processing device.
[0002]
[Prior art]
2. Description of the Related Art There is known an ultrasonic processing apparatus capable of ultrasonically vibrating a tool and transmitting the vibration to abrasive grains to form a shape following a tool shape on a workpiece. Such an ultrasonic processing apparatus is suitable for use in processing a brittle material such as glass, ceramics, ore, and jewelry as the workpiece because it can precisely process the workpiece.
[0003]
In the ultrasonic processing apparatus as described above, the workpiece is transmitted by transmitting the ultrasonic vibration generated by the ultrasonic vibrator to a tool attached thereto through a tool holder which is a longitudinal member called a horn. It is common to process. The horn has an axial bending vibration mode that vibrates so as to bend in the axial direction, a radial expansion vibration mode that vibrates so as to expand and contract in the radial direction, and an axial expansion vibration mode that vibrates so as to expand and contract in the axial direction. In the ultrasonic machining, vibration in any order of the axial stretching vibration mode is used. Accordingly, the ultrasonic vibrator is vibrated at the same frequency as the natural frequency of the horn in the axial stretching vibration mode in the order used for ultrasonic processing.
[0004]
[Problems to be solved by the invention]
However, it is very difficult as a practical matter to make the frequency of the ultrasonic vibration generated by the ultrasonic vibrator exactly coincide with the natural frequency of the horn axial stretching vibration mode in the order used for ultrasonic processing. It is. Therefore, the frequency of the ultrasonic vibration generated by the ultrasonic vibrator fluctuates in a direction closer to the natural frequency in one of the axial bending vibration mode and the radial stretching vibration mode than the originally planned frequency. In such a case, the horn may be excited due to the vibration in the axial bending vibration mode and / or the vibration in the radial stretching vibration mode added to the vibration in the axial stretching vibration mode. Then, for example, the width of the groove formed in the workpiece becomes significantly larger than the design width, and the shape of the workpiece after processing becomes significantly different from the tool shape (design shape). Shape accuracy is deteriorated.
[0005]
Therefore, an object of the present invention is to provide an ultrasonic processing apparatus capable of processing a workpiece with excellent shape accuracy and an ultrasonic vibrator used for the apparatus.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, an ultrasonic machining apparatus according to claim 1 ultrasonically vibrates a tool attached to an ultrasonic vibrator, and transmits the vibration to abrasive grains to form a shape following the tool shape. In the ultrasonic processing apparatus formed on a workpiece, the ultrasonic vibrating body has an axial stretching vibration mode having a natural frequency in a radial stretching vibration mode or an axial bending vibration mode in an order used for ultrasonic processing. It is characterized in that it is formed so as to be 0.90 times or less or 1.10 times or more of the natural frequency of the mode.
[0007]
According to the first aspect, the vibration frequency of the ultrasonic vibrator deviates from the natural frequency of the axial stretching vibration mode of the ultrasonic vibrator in the order used for ultrasonic machining, and the radial stretching vibration mode or the axial bending vibration. Even when approaching the natural frequency of the mode, the vibration in the radial expansion / contraction vibration mode or the axial bending vibration mode is not so excited, and the groove formed in the workpiece becomes thicker than the tool shape. This hardly occurs, and the workpiece can be processed with excellent shape accuracy. Similarly, even if the excitation direction of the ultrasonic vibrator deviates in the radial direction from the axial direction of the ultrasonic vibrator, the vibration in the radial expansion / contraction vibration mode or the axial bending vibration mode is hardly excited, and the excellent shape is obtained. The workpiece can be machined with high accuracy. Further, damage to the tool can be suppressed.
[0008]
Further, in the ultrasonic processing apparatus according to claim 2, the ultrasonic vibrating body has an axial expansion / contraction vibration in a radial expansion / contraction vibration mode or an axial bending vibration mode whose natural frequency is in the order used for ultrasonic processing. It is formed so as to be 0.85 times or less or 1.15 times or more of the natural frequency of the mode.
[0009]
According to the second aspect, the vibration in the radial stretching vibration mode or the axial bending vibration mode is hardly excited, and the workpiece can be processed with further excellent shape accuracy.
[0010]
Further, in the ultrasonic processing apparatus according to claim 3, the ultrasonic vibrating body has an axial stretching vibration mode having a natural frequency in a radial stretching vibration mode and an axial bending vibration mode in an order used for ultrasonic processing. It is formed so as to be 0.85 times or less or 1.15 times or more of the natural frequency of the mode.
[0011]
According to the third aspect, the vibrations in the radial stretching vibration mode and the axial bending vibration mode are hardly excited, and the workpiece can be processed with more excellent shape accuracy.
[0012]
Further, in the ultrasonic machining apparatus according to claim 4, the ultrasonic vibrating body has a divergent shape in which a portion near a tip to which the tool is attached has a larger diameter than a central portion.
[0013]
According to the fourth aspect, since the ultrasonic vibrator is a long member having a divergent shape, for example, superior processing accuracy is obtained as compared with a case where the ultrasonic vibrator is a long member having a body shape or a tapered shape. It was confirmed that it could be obtained.
[0014]
According to a fifth aspect of the present invention, there is provided an ultrasonic oscillator used in the ultrasonic processing apparatus according to any one of the first to fourth aspects.
[0015]
The ultrasonic vibrator according to claim 5 is suitable for use with the ultrasonic processing apparatus described above.
[0016]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.
[0017]
[Schematic configuration of entire device]
FIG. 1 shows an overall side view of an ultrasonic processing apparatus as one embodiment of the present invention, and FIG. 2 shows an overall front view thereof. As shown in FIGS. 1 and 2, the ultrasonic processing apparatus 1 has a configuration in which a column 3 is erected on a base 2 installed on the floor, and a drilling head 4 is supported on the column 3. Has become.
[0018]
The column 3 has a screw shaft 5 arranged vertically and rotatably supported. An elevating body 6 is screwed to the screw shaft 5, and the screw shaft 5 and the elevating body 6 constitute a known ball screw mechanism. A motor shaft of a motor 7 installed on the column 3 is connected to the screw shaft 5. In this configuration, the vertical position of the elevating body 6 can be changed by driving the motor 7 to rotate in the forward and reverse directions.
The column 3 is further provided with a linear guide in the vertical direction (not shown), and a connecting body 8 is provided so as to be vertically displaceable along the linear guide. By connecting the elevating body 6 to the connecting body 8, the connecting body 8 (and, consequently, the drilling head 4 provided in the connecting body 8) can be moved in the vertical direction (Z direction).
[0019]
The connecting body 8 supports the drilling head 4 so as to be slidable up and down. A drilling tool 9 is attached to the drilling head 4 and a mechanism for applying ultrasonic vibration to the tool 9 is provided.
[0020]
A movable table 10 that can move in the horizontal direction (XY directions) is installed on the base 2. On the movable table 10, as shown in FIG. The three are arranged side by side.
A work 13 as a workpiece can be fixed to a position on the upper surface of the elevating table 11 which can face the tool 9. Although various types of the work 13 can be considered, the present embodiment shows a case where a piezoelectric ceramic material (PZT) used as a piezoelectric actuator for an ink jet head of an ink jet printer or the like is processed.
[0021]
A cover 43 is provided on the base 2 so as to cover the entire apparatus, and care has been taken to prevent chips generated during drilling work and abrasive liquid to be described later from scattering around. An openable / closable door 44 is provided on the front of the apparatus (FIG. 1). The door 44 can be opened and the inside of the cover 43 can be accessed as required when replacing the work 13 or the like.
[0022]
[Configuration of drilling head]
The configuration of the drilling head unit 4 will be specifically described mainly with reference to FIG. 3 which is a side view, FIG. 4 which is a front view, and FIG. 5 which is a plan sectional view.
The drilling head 4 has a configuration in which a tool frame 17 for supporting the tool 9 is vertically slidably connected to a base frame 14 supported by the connecting body 8. A support shaft 15 is horizontally installed on the base frame 14, and a central portion of a long and narrow balance body 16 is pivotally supported on the support shaft 15 so as to be swingable.
An air cylinder 18 is installed on the base frame 14 (FIGS. 3 and 4), and this cylinder rod 19 extends downward and is connected to one end of the balance body 16. The tool frame 17 is connected to one end of the balance body 16 to which the cylinder rod 19 is connected. The base frame 14 is provided with a displacement sensor 20, and is configured to detect a relative displacement of the tool frame 17 with respect to the base frame 14.
[0023]
As shown in FIG. 3, an annular horn support 21 is provided at the lower end of the tool frame 17 so as to be pivotable via a bearing 22, and a horn 23 is fixed to the horn support 21. The horn 23 is formed to be elongated in the up-down direction. An ultrasonic vibrator 24 is fixed to an upper portion of the horn 23, and a flat tool mounting surface 23a is formed at a lower end of the horn 23. The tool 9 is detachably attached. In addition, a plate-like cover 45 is provided so as to cover the base frame 14 and the tool frame 17, so that the internal ultrasonic vibrator 24 and the like can be protected.
[0024]
As shown in the plan view of FIG. 5, a projection 25 is provided on the horn support 21 toward the side, and an urging body 26 is provided on the tool frame 17 on one side of the projection 25. The urging body 26 is configured to constantly push the projection 25 toward one side by the elasticity of the urging spring 28. On the other hand, an angle fine adjustment screw 27 having a knob is attached to the tool frame 17 at a position facing the urging body 26 with the projection 25 interposed therebetween.
In this configuration, when the knob of the angle fine adjustment screw 27 is rotated in one direction, its tip pushes the projection 25 against the urging body 26, so that the horn support 21 moves in the counterclockwise direction in FIG. Turned. On the other hand, when the knob is rotated in the opposite direction, the tip of the screw 27 retreats and the urging body 26 pushes the projection 25, so that the horn support 21 is turned clockwise in FIG. Therefore, by appropriately rotating the screw 27, the angle of the horn support 21 (that is, the direction of the tool 9 attached to the horn 23 in the horizontal plane) can be finely adjusted.
A fixing screw 36 is provided on the front surface of the head (FIGS. 3 and 4). After the fine adjustment operation described above is completed, the screw 36 is rotated and tightened, so that the horn support 21 is inadvertently prepared. It can be fixed so that it does not turn.
[0025]
[Configuration of lifting table]
The configuration of the lifting table 11 for fixing the work 13 will be described with reference to the side view of FIG.
The elevating table 11 has a base frame 29 erected and fixed on the moving table 10, and an elevating frame 31 provided on the base frame 29 via a linear guide (not shown) so as to be able to move up and down. I have.
[0026]
A lift cylinder 30 is attached to the base frame 29, and a cylinder rod 32 extends upward, and a tip of the cylinder rod 32 is connected to the lift frame 31.
The lift cylinder 30 is of an air cylinder type, and the vertical position of the lifting frame 31 can be changed by supplying / draining compressed air. A displacement sensor 33 is installed on the base frame 29 so that the vertical position of the lifting frame 31 can be measured.
A box-shaped cover 46 is provided on the lifting frame 31 to protect the internal lift cylinder 30 and the displacement sensor 33.
[0027]
The upper part of the elevating frame 31 is configured horizontally, and the work table 12 on which the work 13 is mounted is installed thereon. Further, a clamp mechanism 34 is provided on the lifting frame 31 at a position beside the work table 12. The clamp mechanism 34 is formed of an air cylinder. When the air cylinder is operated with the work 13 placed on the work table 12, the extending cylinder rod 35 presses the work 13 in the horizontal direction, and the work table 12 and is fixed in a state where it abuts on a guide portion.
[0028]
The ultrasonic processing apparatus 1 includes an abrasive liquid reservoir (not shown), and a liquid in which abrasive grains (for example, SiC having a particle size of about 4 to 6 μm) are dispersed is injected into the abrasive liquid reservoir. I have. An abrasive liquid circulation path composed of a pipe, a flexible hose, a pipe joint, or the like is formed by being connected to the abrasive liquid reservoir, and this path is connected to a relay pipe 47 (FIG. 1, FIG. 2 and 6). A supply hole 48 is formed in the relay pipe 47, and a guide rod 49 projects downward at a position near the supply hole 48. The guide rod 49 is formed in a curved shape and changes its direction in an oblique direction, and its tip is located immediately above the work table 12 on the lifting table 11.
In this configuration, when a pump (not shown) installed in the abrasive liquid reservoir is driven, the abrasive liquid is sent into the relay pipe 47, and a part of the abrasive liquid leaks out through the supply hole 48. The abrasive liquid leaked to the outer surface of the relay pipe 47 falls on the work table 12 along the guide rod 49 and is used for processing by the tool 9.
[0029]
[Explanation of drilling operation]
The operation of actually punching the workpiece 13 by ultrasonically oscillating the tool 9 in the configuration described above will be described.
First, after the work 13 is fixed on the work table 12 by the clamp mechanism 34, the moving table 10 is moved in the X and Y directions, and the motor 7 is driven to lower the drilling head unit 4; As shown by, the tool 9 is positioned just above the work 13 with a slight gap.
Then, while constantly measuring the position of the elevating frame 31 with the displacement sensor 33, compressed air is supplied to the lift cylinder 30, the cylinder rod 32 is gradually extended, and the elevating frame 31 is moved upward to move the work 13 upward. To raise. Then, the position of the elevating frame 31 at the moment when the upper surface of the work 13 comes into contact with the tool 9 is stored as a zero position in an appropriate storage means of the controller that controls the apparatus 1.
Then, the ultrasonic oscillator 24 of the drilling head unit 4 is driven to supply compressed air to the lift cylinder 30 while applying vertical ultrasonic vibration having an amplitude of about several μm to the tool 9 via the horn 23. The work 13 is raised and pressed against the tool 9. When the pump of the abrasive liquid circulation path is driven, the abrasive liquid is supplied from the relay pipe 47 to the periphery of the tool 9 via the guide rod 49.
As a result, the work 13 is cut by the abrasive grains between the work 9 and the work 9, and a groove, a hole, or the like having a shape following the tool 9 is formed on the upper surface of the work 13.
[0030]
The air cylinder 18 (FIG. 3) of the drilling head unit 4 supplies and discharges compressed air as necessary while measuring the displacement of the tool frame 17 with the displacement sensor 20 to support the tool frame 17. Regulating power. This prevents the tool 9 from being pressed against the work 13 with an excessive force during the drilling operation. Therefore, even when the work 13 made of a brittle material such as the piezoelectric ceramic according to the present embodiment is processed, the work 13 is not pressed. The structure is such that damage is sufficiently avoided.
[0031]
The position of the lifting frame 31 is constantly measured by the displacement sensor 33 (FIG. 6) even while the workpiece 9 is being drilled by the tool 9. Then, when the lifting frame 31 rises from the zero position by a predetermined distance, the supply of the compressed air to the lift cylinder 30 is stopped, and the lifting of the work 13 is stopped. As a result, a hole or a groove having a depth corresponding to the distance can be accurately formed in the work 13.
[0032]
[Configuration of camera unit]
Next, the camera unit 41 installed for adjusting the direction of the tool 9 will be described. The camera section 41 is provided at a side position of the lifting table 11 as shown in FIG.
As shown in FIG. 7, the camera section 41 has a box-shaped cover 37, and a CCD video camera 38 is housed inside the cover 37 with its lens section 39 facing upward. A transparent cover 40 is provided on the upper surface of the cover 37 at a position corresponding to the lens unit 39 so as to be openable and closable.
[0033]
The operation of adjusting the direction of the tool 9 in this configuration will be described. While moving the moving table 10 in the X and Y directions, the motor 7 is driven to lower the drilling head unit 4, and the tool 9 is positioned immediately above the lens unit 39 of the camera 38 as shown by a chain line in FIG. By doing so, the direction of the tool 9 can be photographed by the video camera 38. The captured video is displayed in real time on a monitor installed at an appropriate position of the device 1 (for example, a side position of the column 3). The operator can finely adjust the turning angle of the horn 23 by turning the above-described angle fine adjustment screw 27 while watching this image, and can adjust the direction of the tool 9 to be appropriate.
[0034]
[Description of polishing apparatus]
Further, a polishing device 42 for polishing the tool mounting surface 23a of the horn 23 will be described. As shown in FIG. 2, the polishing device 42 is installed on the opposite side of the camera unit 41 with the lifting table 11 interposed therebetween when viewed from the front.
FIG. 8 shows a specific configuration of the polishing apparatus 42. As shown in this figure, the polishing apparatus 42 includes a cylindrical frame 50 erected on the moving table 10 (the moving table 10 is not shown in FIG. 8). The rotary shaft 51 is rotatably supported. A cup-shaped grindstone 52 is fixed to the upper end of the rotating shaft 51. A motor 53 is provided on a side of the rotating shaft 51, and a motor shaft 54 of the motor 53 is connected to the rotating shaft 51 via pulleys 55 and 56 and a belt 57.
[0035]
The state of the polishing operation in this configuration will be described.
That is, with the tool 9 removed from the horn 23, the moving table 10 is moved, and the above-described motor 7 is driven to lower the drilling head unit 4. Then, the motor 53 is driven to rotate the grindstone 52, and the tool mounting surface 23a is moved horizontally while the upper surface of the grindstone 52 is in contact with the tool mounting surface 23a on the lower surface of the horn 23. Can be polished.
A pressure cylinder 58 is provided on the drilling head 4 (FIGS. 3 and 4). The cylinder 58 is used to press the tool mounting surface 23 a of the horn 23 against the grindstone 52.
[0036]
The purpose of the polishing apparatus 42 will be described.
That is, in the ultrasonic machining apparatus 1, when the tool 9 is attached to the horn 23 and ultrasonically oscillated to perform a drilling operation on the work 13, the abrasive grains supplied around the tool 9 are attached to the tool mounting on the lower surface of the horn 23. Invasion between the surface 23a and the tool 9 inevitably causes the tool mounting surface 23a to be gradually worn by the abrasive grains. As the wear of the tool mounting surface 23a progresses, it becomes impossible to mount the tool 9 while keeping the tool 9 in close contact with the horn 23, and ultrasonic vibration cannot be transmitted to the tool 9 efficiently. .
Therefore, in the processing device 1 of the present embodiment, the polishing is performed by the polishing device 42 every time the drilling operation is performed a predetermined number of times, and the tool mounting surface 23a of the horn 23 is shaved to be horizontal. It is designed to be attached in close contact with the device.
[0037]
[Mounting the tool on the horn]
Next, an attachment portion between the horn 23 and the tool 9 will be described in detail. FIG. 9 is an enlarged perspective view in which a part of the horn 23 and the tool 9 in a separated state is broken. As can be seen from FIG. 9, the horn 23 is a long member having a divergent shape in which the tip on the side of the connection with the tool 9 has a larger diameter than the center. It has been confirmed by the present inventor that the horn 23 is formed in the divergent shape in this manner, whereby a higher processing accuracy is obtained than in the case where the horn 23 is formed in a torso shape or a tapered shape described later. I have. This is because, as described later, in the case of the divergent shape, the natural frequency of the radial stretching vibration mode of the horn 23 is set to a value apart from the natural frequency of the axial stretching vibration mode in the order used for ultrasonic machining. It is presumed that one of the reasons is that it is easier to perform the operation than the case of the body shape or the tapered shape. A hard piercing member (for example, PCD (PolyCrystalline Diamond)) 9a for forming a pierced hole in the workpiece is attached to the lower surface of the tool 9.
[0038]
As described above, the tool mounting surface 23a at the tip of the horn 23 is polished by the polishing device 42 to ensure that it is a flat surface. A substantially cylindrical concave portion 61 for mounting the tool 9 is formed near the center of the tool mounting surface 23a along the axial direction of the horn 23. A female screw is formed on the inner peripheral surface of the recess 61. On the other hand, from the upper surface of the tool 9, a columnar convex portion 62 formed to have substantially the same diameter as the concave portion 61 protrudes. A male screw is formed on the outer peripheral surface of the projection 62. The tool 9 is attached to the horn 23 by screwing the protrusion 62 into the recess 61 of the horn 23.
[0039]
[Normal frequency of horn]
Next, the natural frequency of horn 23 in the present embodiment will be described. As described above, the horn 23, which is a longitudinal member having a circular cross section, has an axial stretching vibration mode that vibrates so as to expand and contract in the axial direction as one of the vibration modes. In the embodiment, the secondary vibration mode (natural frequency 19.7 kHz) is used for ultrasonic machining. FIG. 10A shows the state of vibration of the horn 23 in the secondary axial stretching vibration mode. FIG. 10A is a schematic diagram in which each part of the horn is divided according to the magnitude of the amplitude. As can be seen from FIG. 10A, in this vibration mode, the horn 23 is ultrasonically vibrated in the axial direction so that the central part of the horn 23 is slightly below the antinode.
[0040]
A curve A in FIG. 11 shows the relationship between the amplitude and the frequency in the secondary axial stretching vibration mode of the horn 23. In the curve A, the natural frequency of 19.7 kHz in the secondary axial stretching vibration mode is represented as “f1”.
[0041]
Further, in the present embodiment, the horn 23 shown in FIG. 9 has a radial expansion and contraction that vibrates so as to expand and contract in a direction perpendicular to the axial direction by appropriately setting its thickness, length, shape and material. The natural frequency of all the orders of the vibration mode is 0.90 times or less or 1.10 times or more, preferably 0.85 times or less or 1.15 times the natural frequency f1 in the secondary axial stretching vibration mode. More preferably, it is formed to be 0.80 times or less or 1.20 times or more. In the case of the horn 23 shown in FIG. 9, specifically, a third-order radial stretching vibration mode appears as a radial stretching vibration mode having a natural frequency closest to the natural frequency f1, and the natural frequency is 23. .6 kHz (= 1.20f1). Note that the horn 23 also has a radial expansion / contraction vibration mode other than the third-order vibration mode. However, since the natural frequency of the horn 23 is largely apart from the natural frequency f1 in a normal case, no problem occurs here.
[0042]
FIG. 10B shows a state of the vibration of the horn 23 in the third radial stretching vibration mode. As can be seen from FIG. 10B, in this vibration mode, the horn 23 ultrasonically vibrates in the radial direction such that the lowermost portion, the central portion, and the like of the horn 23 become antinodes of vibration.
[0043]
The curve B in FIG. 11 shows the relationship between the amplitude and the frequency of the horn 23 in the third radial stretching vibration mode. In the curve B, the natural frequency of 23.6 kHz in the third-order radial stretching vibration mode is represented as “f2”.
[0044]
When the horn 23 shown in FIG. 9 is used, the ultrasonic vibrator 24 is adjusted so as to oscillate at 19.7 kHz, which is the natural frequency in the secondary axial stretching vibration mode. As can be seen from FIG. 11, at this frequency, the amplitude of the horn shown by curve B is relatively small. Therefore, even if the oscillation frequency of the ultrasonic vibrator 24 is shifted in a direction to become larger than f1, the vibration in the third-order radial stretching vibration mode is hardly excited. Therefore, according to the present embodiment, problems such as the groove formed in the work 13 becoming wider than the tool shape are less likely to occur, and the work 13 can be processed with excellent shape accuracy. Similarly, even if the excitation direction of the ultrasonic vibrator 24 deviates in the radial direction from the axial direction of the horn 23, the vibration in the third radial expansion / contraction vibration mode is hardly excited, and the work 13 has excellent shape accuracy. Can be processed. Further, since the tool 9 hardly vibrates in the radial direction of the horn 23, damage to the tool 9 is also suppressed. In order to enhance these effects, the natural frequency in the third-order radial stretching vibration mode should be a value as far as possible from the natural frequency in the second axial stretching vibration mode. preferable.
[0045]
In this case, the natural frequencies of all the orders in the radial stretching vibration mode of the horn 23 shown in FIG. 9 are set to 0.90 times or less or 1.10 times the natural frequency f1 in the secondary axial stretching vibration mode. Depending on the shape and material of the horn 23, the natural frequency of a part of the radial stretching vibration mode exceeds 0.90 times the natural frequency f1 in the secondary axial stretching vibration mode. However, even if it is less than 1.10 times, the horn 23 is hardly excited in the radial direction due to the reason that the maximum amplitude is small, and may not adversely affect the machining accuracy of the work 13. Therefore, when such a horn 23 has an order that hardly excites radial vibration, the natural frequency of the radial stretching vibration mode in other orders may be within the above-described range, The present invention should be construed to include those in which the natural frequency of the radial stretching vibration mode in some of the orders is within the above-described range. However, from the viewpoint of suppressing the radial vibration of the tool 9, the natural frequencies of all the orders in the radial stretching vibration mode of the horn 23 are set to 0.90 times or less or 1.10 times or more of the natural frequency f1. Needless to say, it is preferable.
[0046]
Thus, in the present embodiment, the natural frequency of the horn 23 in the radial stretching vibration mode shown in FIG. 9 is 0.90 times or less the natural frequency f1 in the secondary axial stretching vibration mode, or 1. The effect of improving the processing accuracy of the work 13 is obtained by setting it to 10 times or more. However, depending on conditions such as the shape of the horn 23, the natural frequency of the radial stretching vibration mode may be used instead of or in addition to the natural frequency. In some cases, an effect of improving the processing accuracy of the work 13 may be obtained by considering an axial bending vibration mode that vibrates so as to bend in the axial direction. That is, even if the horn 23 is formed so that the natural frequency of the axial bending vibration mode is 0.90 times or less or 1.10 times or more of the natural frequency f1, the processing accuracy of the work 13 is improved. And the natural frequency of both the radial stretching vibration mode and the axial bending vibration mode is 0.90 times or less or 1.10 times or more of the natural frequency f1. However, the effect of improving the processing accuracy of the work 13 can be obtained. In particular, by setting both the natural frequency of the radial stretching vibration mode and the natural frequency of the axial bending vibration mode to 0.90 times or less or 1.10 times or more of the natural frequency f1, more excellent effects can be obtained. There is. Even in these cases, it is more preferable that the frequency is 0.85 times or less or 1.15 times or more than the natural frequency f1 is 0.90 times or less or 1.10 times or more. More preferably, it is 0.80 times or less or 1.20 times or more.
[0047]
[Modification of horn]
Next, a modified example of the horn will be described. In the above-described embodiment, the horn has a divergent shape in which the portion near the tip where the tool is attached has a larger diameter than the center portion. However, the horn can take various shapes. FIG. 12A is an enlarged perspective view of a part of the horn 223 having a torso shape having the same diameter as the central part in the vicinity of the tip to which the tool 9 is attached, in a state where the horn 223 is separated from the tool 9. . FIG. 12B is an enlarged perspective view in which a part of the horn 323 having a tapered shape in which the vicinity of the tip to which the tool 9 is attached has a smaller diameter than the center is cut off in a state separated from the tool 9. is there.
[0048]
In the case of the cylinder-type horn 223 shown in FIG. 12A, the secondary vibration mode (a natural frequency of 19.8 kHz: hereinafter sometimes referred to as f3) is used for ultrasonic machining. FIG. 13A shows a state of vibration of the horn 223 in the secondary axial stretching vibration mode. FIG. 13A is a schematic diagram in which each part of the horn is divided according to the magnitude of the amplitude. As can be seen from FIG. 13A, in this vibration mode, the horn 223 ultrasonically vibrates in the axial direction such that the lowermost part and the upper part of the center of the horn 223 become antinodes of vibration.
[0049]
Further, in the present embodiment, the horn 223 shown in FIG. 12A vibrates so as to expand and contract in a direction perpendicular to the axial direction by appropriately setting its thickness, length, shape and material. The natural frequency of all orders in the radial stretching vibration mode is 0.90 times or less, 1.10 times or more, preferably 0.85 times or less, of the natural frequency f3 in the secondary axial stretching vibration mode. It is formed so as to be at least .15 times, more preferably at most 0.80 times or at least 1.20 times. In the case of the horn 223 shown in FIG. 12A, specifically, a third-order radial stretching vibration mode appears as a radial stretching vibration mode having a natural frequency closest to the natural frequency f3, and the natural vibration thereof The number is set to 22.4 kHz (= 1.13f3). The horn 223 also has a radial expansion / contraction vibration mode other than the third-order vibration mode. However, since the natural frequency of the horn 223 is largely apart from the natural frequency f3 in a normal case, it does not matter here.
[0050]
FIG. 13B shows the state of vibration of the horn 223 in the third radial stretching vibration mode. As can be seen from FIG. 13B, in this vibration mode, the horn 223 ultrasonically vibrates in the radial direction such that the flange portion of the horn 223 becomes an antinode of the vibration.
[0051]
When the horn 223 shown in FIG. 12A is used, the ultrasonic vibrator 24 is adjusted so as to oscillate at 19.8 kHz, which is the natural frequency in the secondary axial stretching vibration mode. At this frequency, the amplitude of the horn in the third-order radial stretching vibration mode is relatively small. Therefore, even if the oscillation frequency of the ultrasonic vibrator 24 is shifted in a direction to become larger than f3, the vibration in the third-order radial stretching vibration mode is hardly excited. Therefore, according to the present embodiment, problems such as the groove formed in the work 13 becoming wider than the tool shape are less likely to occur, and the work 13 can be processed with excellent shape accuracy. Similarly, even if the excitation direction of the ultrasonic vibrator 24 deviates in the radial direction from the axial direction of the horn 223, the vibration in the third radial expansion / contraction vibration mode is hardly excited, and the work 13 has excellent shape accuracy. Can be processed. In addition, since the tool 9 hardly vibrates in the radial direction of the horn 223, damage to the tool 9 is also suppressed. In order to enhance these effects, the natural frequency in the third-order radial stretching vibration mode should be a value as far as possible from the natural frequency in the second axial stretching vibration mode. preferable.
[0052]
On the other hand, in the case of the tapered horn 323 shown in FIG. 12B, its secondary vibration mode (natural frequency: 20.0 kHz; hereinafter, sometimes referred to as f4) is used for ultrasonic machining. FIG. 14A shows the state of vibration of the horn 323 in the secondary axial stretching vibration mode. FIG. 14A is a schematic diagram in which each part of the horn is divided according to the magnitude of the amplitude. As can be seen from FIG. 14A, in this vibration mode, the horn 223 is ultrasonically vibrated in the axial direction such that the lowermost part of the horn 323 is a vibration antinode.
[0053]
Further, in this embodiment, the horn 323 shown in FIG. 12B vibrates so as to expand and contract in a direction orthogonal to the axial direction by appropriately setting its thickness, length, shape and material. The natural frequencies of all orders in the radial stretching vibration mode are 0.90 times or less, 1.10 times or more, preferably 0.85 times or less, of the natural frequency f4 in the secondary axial stretching vibration mode. It is formed so that it becomes .15 times or more, more preferably 0.80 times or less or 1.20 times or more. In the case of the horn 323 shown in FIG. 12B, specifically, a third-order radial stretching vibration mode appears as a radial stretching vibration mode having a natural frequency closest to the natural frequency f4, and its natural vibration The number is set to 22.0 kHz (= 1.10f4). Note that the horn 323 also has a radial expansion / contraction vibration mode other than the third-order vibration mode. However, since the natural frequency of the horn 323 is largely apart from the natural frequency f3 in a normal case, there is no problem here.
[0054]
FIG. 14B shows a state of vibration of the horn 323 in the third radial stretching vibration mode. As can be seen from FIG. 14B, in this vibration mode, the horn 323 ultrasonically vibrates in the radial direction such that the flange portion of the horn 323 becomes an antinode of the vibration.
[0055]
When the horn 323 shown in FIG. 12B is used, the ultrasonic vibrator 24 is adjusted to oscillate at 20.0 kHz, which is the natural frequency in the secondary axial stretching vibration mode. At this frequency, the amplitude of the horn in the third-order radial stretching vibration mode is relatively small. Therefore, even if the oscillation frequency of the ultrasonic vibrator 24 is shifted in a direction to become larger than f4, the vibration in the third radial expansion / contraction vibration mode is hardly excited. Therefore, according to the present embodiment, problems such as the groove formed in the work 13 becoming wider than the tool shape are less likely to occur, and the work 13 can be processed with excellent shape accuracy. Similarly, even if the excitation direction of the ultrasonic vibrator 24 is deviated in the radial direction from the axial direction of the horn 323, the vibration in the third radial expansion / contraction vibration mode is not so much excited, and the workpiece 13 has excellent shape accuracy. Can be processed. Further, since the tool 9 hardly vibrates in the radial direction of the horn 323, damage to the tool 9 is also suppressed. In order to enhance these effects, the natural frequency in the third-order radial stretching vibration mode should be a value as far as possible from the natural frequency in the second axial stretching vibration mode. preferable.
[0056]
In the bobbin horn and the tapered horn described in the above two modified examples, the natural frequency of the secondary axial stretching vibration mode used for ultrasonic machining and the natural vibration of the tertiary radial stretching vibration mode are used. The difference from the number is smaller than that of the divergent horn described in the above embodiment. Therefore, from the viewpoint of improving the machining accuracy of the workpiece by suppressing the vibration of the tool in the radial direction, the divergent horn 23 shown in FIG. 9 is different from the horn 23 and the tapered horn 223 shown in FIGS. It can be said that it is superior to the mold horn 323.
[0057]
In the two modifications described above, as in the case of the horn 23 described with reference to FIG. 9, depending on the shapes and materials of the horns 223 and 323, the natural frequency of a partial order of the radial expansion and contraction vibration mode is a secondary Even if the natural frequency f3, f4 in the axial stretching vibration mode is more than 0.90 times or less than 1.10 times, the horns 223, 323 have radial directions because of their small maximum amplitude. Is hardly excited, and may not adversely affect the processing accuracy of the work 13. Therefore, when such horns 223 and 323 have an order that hardly excites the radial vibration, the natural frequency of the radial expansion and contraction vibration mode in the other orders is set within the range described above. Good. However, also in this modification, from the viewpoint of suppressing the radial vibration of the tool 9, the natural frequencies of all the orders of the radial expansion and contraction vibration modes of the horns 223 and 323 are set to 0.90 times or less of the natural frequency f1 or Needless to say, it is preferable to set it to 1.10 times or more. Further, also in the case of the above two modifications, depending on conditions such as the shape of the horn 23, the axial bending vibration mode may be considered instead of or in addition to the natural frequency of the radial stretching vibration mode. In some cases, an effect of improving the processing accuracy of the work 13 may be obtained.
[0058]
The preferred embodiment of the present invention has been described above. However, the present invention is not limited to the above-described embodiment, and various design changes can be made within the scope of the appended claims. For example, in the above-described embodiment, the order used for ultrasonic processing is the secondary axial stretching vibration mode, but the first and third axial stretching vibration modes may be used for ultrasonic processing. . Further, the cross-sectional shape of the horn does not necessarily have to be a circle, and any other cross-sectional shape can be adopted. In the above-described embodiment, a horn is used as the ultrasonic vibrator, but a tool may be attached to the ultrasonic vibrator or another ultrasonic vibrator without using the horn.
[0059]
【The invention's effect】
As described above, according to the first aspect, the vibration frequency of the ultrasonic vibrator deviates from the natural frequency of the axial vibration mode of the ultrasonic vibrator in the order used for ultrasonic processing, and the radial expansion vibration Even when approaching the natural frequency of the mode or the axial bending vibration mode, the vibration in the radial stretching vibration mode or the axial bending vibration mode is not much excited, and the groove formed in the workpiece is smaller than the tool shape. Problems such as thickening are less likely to occur, and the workpiece can be machined with excellent shape accuracy. Similarly, even if the excitation direction of the ultrasonic vibrator deviates in the radial direction from the axial direction of the ultrasonic vibrator, the vibration in the radial expansion / contraction vibration mode or the axial bending vibration mode is hardly excited, and the excellent shape is obtained. The workpiece can be machined with high accuracy. Further, damage to the tool can be suppressed.
[0060]
According to the second aspect, the vibration in the radial stretching vibration mode or the axial bending vibration mode is hardly excited, and the workpiece can be processed with further excellent shape accuracy. According to the third aspect, the vibrations in the radial stretching vibration mode and the axial bending vibration mode are hardly excited, and the workpiece can be processed with more excellent shape accuracy.
[0061]
According to claim 4, since the ultrasonic vibrator is a long member having a divergent shape, for example, excellent processing accuracy is obtained as compared with a case where the ultrasonic vibrator is a long member having a hollow body shape or a tapered shape. can get. The ultrasonic vibrator according to claim 5 is suitable for use with the ultrasonic processing apparatus described above.
[Brief description of the drawings]
FIG. 1 is a side view showing an overall configuration of an ultrasonic perforation apparatus according to an embodiment of the present invention.
FIG. 2 is a front view of the same.
FIG. 3 is a side view and a partial cross-sectional view of a drilling head unit.
FIG. 4 is a front view of the same.
FIG. 5 is a plan sectional view of the same.
FIG. 6 is a side sectional view of a lifting table.
FIG. 7 is a side sectional view of a camera unit.
FIG. 8 is a front sectional view of the polishing apparatus.
9 is an enlarged perspective view in which a horn and a tool having a divergent shape used in the ultrasonic drilling device shown in FIG. 1 are partially cut away in a separated state.
FIG. 10 is a schematic diagram illustrating a state of vibration of a horn having a divergent shape in a secondary axial stretching vibration mode and a tertiary radial stretching vibration mode.
FIG. 11 is a graph illustrating the relationship between the amplitude and the frequency of a horn having a divergent shape in a second-order axial stretching vibration mode and a third-order radial stretching vibration mode.
FIG. 12 is an enlarged perspective view in which a horn and a tool having a barrel shape and a tapered shape are partially broken in a separated state.
FIG. 13 is a schematic diagram illustrating a vibration state of a horn having a torso shape in a secondary axial stretching vibration mode and a tertiary radial stretching vibration mode.
FIG. 14 is a schematic diagram illustrating a state of vibration of a horn having a tapered shape in a secondary axial stretching vibration mode and a tertiary radial stretching vibration mode.
[Explanation of symbols]
1 Ultrasonic processing equipment
2 bases
3 columns
4 Drilling head
8 Connected body
9 Tools
10 Moving table
11 lifting table
12 Work table
13 Work
14 Base frame
16 Balance body
17 Tool frame
18 Air cylinder
19 Cylinder rod
21 Horn support
23 Horn
24 Ultrasonic transducer
26 urging body
27 Angle fine adjustment screw
29 Base frame
31 lifting frame
33 Displacement sensor
34 Clamp mechanism
38 Video Camera
41 Camera section
42 Polishing device
43 cover
47 Relay pipe
48 Supply hole
49 guide bar

Claims (5)

Ultrasonic vibration of the tool attached to the ultrasonic vibrator, in the ultrasonic processing apparatus that forms a shape following the tool shape on the workpiece by transmitting this vibration to the abrasive grains,
The ultrasonic vibrator has a natural frequency of the radial stretching vibration mode or the axial bending vibration mode of 0.90 times or less the natural frequency of the axial stretching vibration mode in the order used for ultrasonic processing. An ultrasonic processing apparatus characterized by being formed so as to have a ratio of 1.10 or more. The ultrasonic vibration body, the natural frequency of the radial expansion vibration mode or the axial bending vibration mode is 0.85 times or less the natural frequency of the axial expansion vibration mode in the order used for ultrasonic processing or The ultrasonic processing apparatus according to claim 1, wherein the ultrasonic processing apparatus is formed so as to be 1.15 times or more. The ultrasonic vibrator has a natural frequency of the radial stretching vibration mode and the axial bending vibration mode of 0.85 times or less the natural frequency of the axial stretching vibration mode in the order used for ultrasonic processing or The ultrasonic processing apparatus according to claim 1, wherein the ultrasonic processing apparatus is formed so as to be 1.15 times or more. The ultrasonic vibrator according to any one of claims 1 to 3, wherein a portion near a tip to which the tool is attached has a divergent shape whose diameter is larger than a center portion. Ultrasonic processing equipment. An ultrasonic vibrator used in the ultrasonic processing apparatus according to claim 1.

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