JP4137843B2 - Ultrasonic processing equipment - Google Patents

Description

The present invention relates to an ultrasonic machining apparatus that accurately creates a minute concave spherical surface at a desired depth with respect to an optical element such as a lens.

2. Description of the Related Art Conventionally, various apparatuses for creating a minute concave spherical surface on a workpiece of an optical element such as a lens are known. For example, an ultrasonic processing apparatus that performs generation processing using ultrasonic waves is known (see, for example, Patent Document 1 and Patent Document 2).
This type of ultrasonic processing apparatus has a spherical tool for creating a concave spherical surface on a workpiece such as a lens, and a concave holding portion for holding the spherical tool in a freely rolling manner. And a horn for ultrasonically vibrating the tool held in the holding portion with ultrasonic waves from an ultrasonic transmitter.
Here, FIGS. 7 and 8 show an example of the horn and the holding portion.
As shown in FIG. 7, the tip of the horn 20 is provided with a holding portion 21 formed in a concave sphere R shape, and a spherical tool 22 is held on the holding portion 21. The spherical tool 22 is disposed adjacent to the lens 23.
Moreover, as shown in FIG. 8, the holding | maintenance part 21 formed in the cone shape is also known.

When the concave spherical surface is processed on the surface of the lens 23 by the ultrasonic processing apparatus configured as described above, the horn 20 is ultrasonically vibrated by the ultrasonic transmitter while the spherical tool 22 is rolled. However, the spherical tool 22 and the lens 23 are brought into contact with each other. At this time, the working fluid is supplied to the contact portion. Thereby, the concave spherical surface can be processed on the surface of the lens 23.
JP 11-333702 A JP 2001-138185 A

However, in the above-described conventional method, the horn 20 and the spherical tool 22 are likely to be misaligned, and the centering reproducibility when the spherical tool 22 is mounted on the holding portion 21 cannot be obtained. . In addition, there is a problem that the coaxiality between the horn 20 and the spherical tool 22 changes when processing by ultrasonic waves is performed.
That is, as shown in FIGS. 7 and 8, it is important that the lens 23, the spherical tool 22 and the horn 20 are coaxial with respect to the axis. However, when the concave spherical surface is formed on the lens 23 by processing, the contact surface of the holding portion 21 with the spherical tool 22 is similarly processed into a concave spherical shape. Thereby, as shown in FIG.7 (b) and FIG.8 (b), the shift | offset | difference of the axial center of the holding | maintenance part 21 and the spherical tool 22 will arise. That is, when the spherical tool 22 moves freely, in other words, it is not accurately held, and thus the above-described deviation occurs.

  The present invention has been made in view of such problems, and an object of the present invention is to be able to hold a spherical tool accurately and with high accuracy and to position it with high accuracy and efficiency. It is to provide a sonication device.

In order to achieve the above object, the present invention provides the following means.
The invention according to claim 1 has a spherical tool for processing a concave spherical surface on a workpiece, and a concave holding portion for holding the spherical tool so as to be capable of rolling, and is held in the holding portion. A horn for ultrasonically vibrating a spherical tool, a mounting table for fixing the workpiece at a position facing the spherical tool held by the horn, and the spherical tool and the workpiece A pressurizing means for contacting with pressure, a measuring means for measuring a relative displacement amount between the mounting table and the spherical tool from a contact state by the pressurizing means, and a working fluid in which abrasive grains are dispersed, A working fluid supply means for supplying to the interface between the workpiece and the spherical tool, and the horn is formed in a tapered shape whose outer shape narrows for a while toward the spherical tool, and the holding portion Is formed in a cylindrical or conical recess, and the inside of the sphere Holds the tool, guide holes for positioning the spherical tool to provide an ultrasonic machining device provided inside when holding the spherical tool.

In the ultrasonic machining apparatus according to the present invention, a spherical tool held for rolling on a horn and a work piece fixed to a mounting table are subjected to a predetermined pressure (predetermined load) by a pressing means. In this state, the spherical tool is rolled and the horn is ultrasonically vibrated. This ultrasonic vibration is transmitted to the spherical tool through the horn. The spherical tool rolls while being ultrasonically vibrated, so that a concave spherical surface can be processed (created) in the workpiece while suppressing the partial friction of the spherical tool. Then, the relative displacement between the mounting table and the spherical tool is measured by the measuring means, and processing is performed until the measured displacement reaches a predetermined value. Thereby, the concave spherical surface of a desired depth can be processed.
As described above, since the processing can be performed in a state where the partial friction of the spherical tool is suppressed, it is possible to process a concave spherical surface with good shape accuracy and a stable curvature. In particular, during machining of the concave spherical surface, the machining fluid is supplied to the interface between the workpiece and the spherical tool by the machining fluid supply means, so that the spherical tool can be favorably rolled in the holding portion.
Further, the horn is formed in a taper shape whose outer shape becomes narrower (tapered) for a while toward the spherical tool, so that the ultrasonic vibration is transmitted to the spherical tool in an amplified state. Thereby, the spherical tool can perform efficient ultrasonic vibration and can process the concave spherical surface with high accuracy.

  Furthermore, since the holding portion is formed in a cylindrical or conical recess, and a guide hole for positioning the spherical tool is provided therein, the spherical tool can be easily and accurately held. The axis of the horn and the axis of the spherical tool can be matched. In other words, since the guide hole is formed in the holding portion, the spherical tool is always guided in this guide hole and is in the same position, that is, the positional relationship in which the axis of the horn coincides with the axis of the spherical tool. Is maintained. In this way, since the rollable spherical tool can be accurately held, there is no deviation of the axial center as in the prior art, and the concave spherical surface can be processed with high accuracy.

  The invention according to claim 2 provides the ultrasonic processing apparatus according to claim 1, wherein the horn is formed so that a peripheral edge portion of the horn covers a hemisphere or more of the spherical tool. .

  In the ultrasonic machining apparatus according to the present invention, the peripheral edge of the tip of the horn covers more than the hemisphere of the spherical tool, so that the spherical tool rolls in a more stable state and the axis is not easily displaced. Therefore, the concave spherical surface can be processed with higher accuracy.

According to the ultrasonic machining apparatus of the present invention, a minute concave spherical surface and its depth can be created with high accuracy by using a device having a simple structure and a tool that is relatively inexpensive and easily available despite high accuracy. can do.
Furthermore, since the holding portion is formed in a cylindrical or conical recess, and a guide hole for positioning the spherical tool is provided therein, the spherical tool can be easily and accurately held. The axis of the horn and the axis of the spherical tool can be matched. Therefore, there is no deviation of the axial center as in the conventional case, and the concave spherical surface can be processed with high accuracy.

Hereinafter, a first embodiment of an ultrasonic machining apparatus according to the present invention will be described with reference to FIGS. 1 to 4.
As shown in FIGS. 1 to 3, the ultrasonic processing apparatus 1 of the present embodiment includes a spherical tool 3 for processing a concave spherical surface 2 b on an upper surface 2 a of a lens (workpiece) 2, and the spherical tool 3. A horn 5 that has a concave holding portion 4 that is held to roll freely at the tip (one end) and that vibrates the spherical tool 3 held in the holding portion 4 ultrasonically, and a spherical shape held by the horn 5 A mounting table 6 for fixing the lens 2 at a position facing the tool 3, a cylinder (pressurizing means) 7 for bringing the spherical tool 3 and the lens 2 into contact with each other with a predetermined pressure, and a contact state by the cylinder 7 A micrometer 8 (measuring means) for measuring the relative displacement between the mounting table 6 and the spherical tool 3 and a working fluid B in which abrasive grains A are dispersed are applied to the interface between the lens 2 and the spherical tool 3. A dispenser (processing fluid supply means) 9 is provided.

Further, as shown in FIG. 1, the ultrasonic processing apparatus 1 of the present embodiment has a processing shaft portion 10 on the side to be processed disposed above and a work shaft portion 11 on the side to be processed. It is arranged below.
The processing shaft portion 10 is movable in the vertical direction along a guide 12 attached to the upper portion of a gantry (not shown), and this movement is fixed at a fixed position. Further, the machining shaft portion 10 includes an ultrasonic transmitter 14 whose output is controlled by the controller 13, a shaft body 15 provided integrally with a lower end portion of the ultrasonic transmitter 14, and a lower end of the shaft body 15. And the spherical tool 3 is attached to the lower end of the horn 5.

The work shaft portion 11 includes the mounting table 6 and the cylinder 7 that supports the mounting table 6. The cylinder 7 acts as a pressurizing unit that presses the mounting table 6 upward in a state where the spherical tool 3 and the lens 2 are in contact with each other and applies a load in the direction of the spherical tool 3. Thereby, the spherical tool 3 and the lens 2 are brought into contact with each other with a predetermined pressure.
The micrometer 8 is in contact with the upper surface 6 a of the mounting table 6, and the amount of displacement in the vertical direction of the mounting table 6 due to the spherical processing on the lens 2 is measured. The micrometer 8 serves as a measuring unit that measures the amount of displacement of the mounting table 6 in accordance with the processing (creation) of the concave spherical surface 2 b on the lens 2. Instead of measuring the displacement amount of the mounting table 6, the mounting table 6 side may be fixed at a fixed position, and the vertical displacement amount of the spherical tool 3 may be measured. That is, it is only necessary that the relative displacement between the mounting table 6 and the lens 2 can be measured.
Further, the dispenser 9 is provided at a contact portion between the spherical tool 3 and the lens 2 to drop and supply the processing liquid B in which diamond powder as the abrasive grains A is dispersed in water. The dispenser 9 functions as a processing liquid supply unit that supplies the processing liquid B.

The horn 5 is formed in a tapered shape whose outer shape becomes narrower (tapered) for a while toward the spherical tool 3.
Here, the attachment part of the spherical tool 3 in the horn 5 is shown in FIG. As shown in FIG. 3, the holding portion 4 formed in a cylindrical shape is formed at the lower end portion of the horn 5, and the spherical tool 3 is inserted into the holding portion 4, thereby forming a spherical shape. The tool 3 is held in a rollable state. Further, the inner diameter of the holding portion 4 is set to a size that allows the spherical tool 3 to be fitted.
Furthermore, a guide hole 16 having a circular cross section is provided inside the holding portion 4 so that the spherical tool 3 is positioned when the spherical tool 3 is held, and has a smaller diameter than the inner diameter of the holding portion 4. Yes. The axis of the guide hole 16 is formed (coaxially) along the axis C of the horn 5. In addition, the spherical tool 3 is guided by the guide hole 16 when held in the holding portion 4, that is, guided by the peripheral edge of the end portion of the guide hole 16, and the spherical tool 3 and the spherical tool 3. It is positioned at a position where the axis of 3 coincides.
Further, the horn 5 is formed such that when the spherical tool 3 is held, the tip periphery covers the hemisphere or more of the spherical tool 3. That is, the hemisphere or more of the spherical tool 3 is held by the holding unit 4.

The case where the ultrasonic processing apparatus 1 configured as described above is operated to process (create) the concave spherical surface 2b on the upper surface 2a of the lens 2 will be described.
First, the spherical tool 3 is held at the lower end of the horn 5 of the processing shaft portion 10. That is, as shown in FIG. 3, the spherical tool 3 is inserted into the holding portion 4 at the lower end of the horn 5 and held so as to roll freely. At this time, the spherical tool 4 is guided by the guide hole 16 and is positioned so that the axis of the spherical tool 4 coincides with the axis C of the horn 5, and more than a hemisphere is held. That is, the spherical tool 3 has a hemisphere or less protruding from the lower end of the horn.
Then, while holding the spherical tool 3, as shown in FIG. 1, the ultrasonic transmitter 14, the shaft body 15 and the horn 5 are lowered by the guide 12 and fixed to the spherical tool 3 and the mounting table 6. The upper surface 2a of the lens 2 is brought into contact with the lens 2, and the processing shaft portion 10 is fixed in this state.

After the contact, the mounting table 6 is directed upward (on the spherical tool 3 side) by the cylinder 7 to apply a load, thereby bringing the spherical tool 3 and the lens 2 into contact with each other with a predetermined pressure. The micrometer 8 measures the displacement with this contact state as a reference. Then, as shown in FIG. 2, the processing liquid B is dropped by the dispenser 9 onto the contact portion between the spherical tool 3 and the lens 2.
In this state, processing is performed by giving an ultrasonic output from the ultrasonic transmitter 14 to the controller 13. This ultrasonic vibration is transmitted to the spherical tool 3 through the shaft body 15 and the horn 5. As a result, the spherical tool 3 rolls while having a moment of microscopically disengaging from the horn 5 and the lens 2. Thus, since the spherical tool 3 rolls while being ultrasonically vibrated, the concave spherical surface 2b is processed on the upper surface 2a of the lens 2 as shown in FIG. can do.
In particular, during machining, the spherical tool 3 is held by the horn 5 so as to be freely rollable, and since the machining liquid B using water as a medium is used, the spherical tool 3 rolls well in the holding unit 4. be able to. Further, since the horn 5 is formed in a tapered shape that becomes narrower toward the spherical tool 3, it can be transmitted to the spherical tool 3 in a state where the ultrasonic vibration is amplified. Therefore, the spherical tool 3 can perform efficient ultrasonic vibration, and can process the concave spherical surface 2b with high accuracy.

  As the processing described above proceeds and the concave spherical surface 2b is processed (created) on the lens 2, the mounting table 6 loaded with a predetermined load by the cylinder 7 is displaced upward. This displacement amount can be read by the micrometer 8. The amount of displacement conforms to the sum of the depth of the concave spherical surface 2b created on the lens 2 and the diameter of the abrasive grain A. Therefore, when the target depth is read by the micrometer 8, the ultrasonic oscillation is stopped. Finish processing. Thereby, the concave spherical surface 2b having a desired depth can be processed.

In particular, since the guide hole 16 is formed in the holding portion 4 during the above-described processing, the spherical tool 3 is always guided by the guide hole 16 and is located at the same position, that is, the axis C of the horn 5. The positional relationship in which the axis of the spherical tool 3 coincides is maintained. That is, since the rollable spherical tool 3 can be accurately held, the axis C of the horn 5 and the axis of the spherical tool 3 do not deviate from the conventional one. Therefore, the concave spherical surface 2b can be processed with high accuracy.
Further, in the processing, the holding part 4 is processed into a concave spherical surface, for example, in contact with the spherical tool 3, but in this embodiment, the guide hole 16 is provided. As shown in FIG. 4, even if the shape change 16a due to processing occurs in the holding portion 4, the spherical tool 3 is guided by the guide hole 16 and follows, so the axis C of the horn 5 and the axis of the spherical tool 3 There is no misalignment. (The axis C of the horn 5 and the axis of the shape change 16a are always coaxial)
In addition, since the spherical tool 3 is covered with the peripheral edge of the tip of the horn 5 at the hemisphere or more, it rolls stably without rattling, and the axis is more difficult to shift. This also makes it possible to process the concave spherical surface 2b with high accuracy.
Further, when processing the next lens 2, since the spherical tool 3 is held by the cylindrical holding portion 4 having the guide hole 16, the axis of the spherical tool 4 and the axis C of the horn 5 Will not slip.

As described above, according to the ultrasonic machining apparatus 1 of the present embodiment, the minute concave spherical surface 2b and its tool can be obtained by using an apparatus having a simple structure and a tool that can be easily obtained at a relatively low cost in spite of high accuracy. Depth can be created with high accuracy.
Further, since the axial center of the spherical tool 3 and the axial center C of the horn 5 are always constant, the outer shape of the lens 2 and the coaxiality of the concave spherical surface 2b can be created with high accuracy.

Next, a second embodiment of the ultrasonic machining apparatus according to the present invention will be described with reference to FIGS. In the second embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.
The difference between the second embodiment and the first embodiment is that in the first embodiment, the holding portion 4 is formed to be recessed in a cylindrical shape, whereas the holding portion 4 of the second embodiment is different from FIG. And as shown in FIG. 6, it is a point recessed and formed in the cone shape. In this embodiment, the spherical tool 3 has a hemisphere or more protruding from the horn 5.
This embodiment can also exhibit the same effects as the first embodiment. As in the first embodiment, the tip peripheral edge of the horn 5 may be formed so as to cover the hemisphere or more of the spherical tool 3.

1 is a schematic configuration diagram of a first embodiment of an ultrasonic machining apparatus according to the present invention. It is an enlarged view of the contact part of the spherical tool and lens in the ultrasonic processing apparatus shown in FIG. It is an expanded sectional view of the horn front-end | tip of the ultrasonic processing apparatus shown in FIG. 1, Comprising: It is a figure which shows the structure of a holding part and a guide hole. It is a figure which shows the shape change by the process which arose in the contact surface of the holding | maintenance part shown in FIG. 3, and a spherical tool. It is an expanded sectional view of the horn tip of a 2nd embodiment of the ultrasonic processing device concerning the present invention, and is a figure showing composition of a holding part and a guide hole. It is a figure which shows the shape change by the process which arose in the contact surface of the holding | maintenance part shown in FIG. 5, and a spherical tool. It is an example which shows the holding | maintenance part of the horn tip of the conventional ultrasonic processing apparatus. It is another example which shows the holding | maintenance part of the horn tip of the conventional ultrasonic processing apparatus.

Explanation of symbols

B Processing fluid 1 Ultrasonic processing device 2 Lens (workpiece)
2b Concave spherical surface 3 Spherical tool 4 Holding part 5 Horn 6 Mounting table 7 Cylinder (pressurizing means)
8 micrometers (measuring means)
9 Dispenser (working fluid supply means)
16 Guide hole

Claims (2)

A spherical tool for machining a concave spherical surface on the workpiece;
A horn that has a concave holding part that holds the spherical tool in a rollable manner at one end, and ultrasonically vibrates the spherical tool held in the holding part;
A mounting table for fixing the workpiece to a position facing the spherical tool held by the horn;
Pressurizing means for bringing the spherical tool and the workpiece into contact with each other at a predetermined pressure;
Measuring means for measuring a relative displacement amount between the mounting table and the spherical tool from a contact state by the pressing means;
A machining fluid supply means for supplying a machining fluid in which abrasive grains are dispersed to an interface between the workpiece and the spherical tool;
The horn is formed in a tapered shape whose outer shape becomes narrower for a while toward the spherical tool,
The holding portion is formed to be recessed in a cylindrical shape or a conical shape to hold the spherical tool therein, and a guide hole for positioning the spherical tool when the spherical tool is held is provided inside. An ultrasonic processing apparatus characterized by comprising: The ultrasonic processing apparatus according to claim 1,
The ultrasonic processing apparatus, wherein the horn is formed so that a peripheral edge portion of the horn covers a hemisphere or more of the spherical tool.

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