JP2007268505A - Device for generating ultrasonic vibration on rotary shaft - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ultrasonic generation device excellent in durability and having good controllability by improving a technique of generating ultrasonic vibration on a rotary shaft in the axial direction. <P>SOLUTION: Wavelength of ultrasonic wave in a rotary shaft is defined as λ, the length of the rotary shaft is set to be 3λ/2 and points at λ/4 distance (equivalent to nodes of the vibration) from both ends are journalled with bearings 9. A magnetic flange 10C and a magnetic flange 10E are fixed at points at λ/2 from both ends (equivalent to antinodes of the vibration) and an electromagnet 11 and an electromagnet 12 are set on the opposite to these magnetic flanges at an interval. Alternating voltage with ultrasonic cycle generated in an ultrasonic vibration oscillating circuit S is applied to the electromagnet 11 and the electromagnet 12. The electromagnets intermittently apply magnetically attracting power with the ultrasonic cycle to the magnetic flanges to cause ultrasonic vibration on the magnetic flanges. The ultrasonic vibration is transmitted to the rotary shaft 7 and the rotary shaft is vibrated by the ultrasonic vibration. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an apparatus that generates ultrasonic vibration on a rotating shaft without contact with the rotating shaft, and is particularly improved so as to have excellent durability and good controllability.

When ultrasonic vibration is generated on the rotating shaft, many effects can be expected, such as improving the surface roughness of the grinding surface by mounting a rotating grindstone on the rotating shaft.
For this reason, various ultrasonic generation techniques have been proposed.
For example, the technique described in Japanese Patent Application Laid-Open No. 2003-145395 cited as Patent Document 1 generates an ultrasonic vibration by attaching an ultrasonic vibrator made of an electrostrictive element to a rotating shaft.
In addition, the technique described in Japanese Patent Application Laid-Open No. 2005-210863 cited as Patent Document 2 generates ultrasonic vibrations by a magnetic force between a permanent magnet that is fixedly installed and a permanent magnet that is attached to a rotating shaft. I am letting.

FIG. 4 is a typical drawing of Japanese Patent Application Laid-Open No. 2003-145395. Reference numeral 3 denotes a spindle body which is rotationally driven. A main body sleeve 3b is formed on the spindle main body 3, and an ultrasonic transducer 4 made of an electrostrictive element is disposed therein. The support horn 6 is connected to the ultrasonic transducer 4 and a flange formed on the support horn 6 is slidably in contact with the inner peripheral surface of the main body sleeve 3b.
According to the invention disclosed in Japanese Patent Application Laid-Open No. 2003-145395 described above, it is reported that the machining accuracy is improved and the number of assembling steps is reduced.
JP 2003-145395 A Japanese Patent Laying-Open No. 2005-210863

According to the ultrasonic vibration generator using the electrostrictive element, the processing accuracy is improved and the controllability is good, so that its value is high. However,
(I). Since the electrostrictive element is not durable, it is often necessary to replace the electrostrictive element. For this reason, the cost of replacement parts is high, and it is troublesome, reducing the operating rate of the mechanical device.
Furthermore, since a brush must be used to supply electric energy to the electrostrictive element, maintenance is not good.

(B). An ultrasonic vibration generator using a permanent magnet is excellent in durability and maintainability, but the vibration frequency is proportional to the rotational speed of the shaft. For this reason, when the rotational speed is adjusted, the vibration frequency changes.
In addition, the amplitude can be controlled but is not easy.
The present invention has been made in view of the circumstances described above, and the object is as follows.
It is an object of the present invention to provide an ultrasonic vibration generation technique that can be driven in a non-contact ultrasonic manner, does not need to be supplied with a brush, and has excellent durability, controllability, and maintainability.

The basic principle of the present invention created to achieve the above object will be briefly described with reference to FIG. 1 corresponding to one embodiment thereof.
A flange 10 made of a magnetic material is fixed to the central portion of the rotating shaft 7 in the vicinity of the portion corresponding to the vibration node (even if it is positioned in the vicinity of the vibration antinode instead of the vicinity of the vibration node). Good, or halfway between nodes and belly)
The electromagnet 11 is arranged on one side of the magnetic body flange 10, and the electromagnet 12 is arranged on the other side.
When the alternating current of the ultrasonic cycle oscillated by the ultrasonic vibration oscillation circuit S is alternately applied to the electromagnet 11 and the electromagnet 12, the magnetic body flange 10 vibrates ultrasonically and the rotating shaft 7 vibrates ultrasonically.
The rotating shaft 7 supports a portion corresponding to the vibration node by a bearing. Although the above-mentioned vibration node is theoretically a point, it is impossible to support a point as an actual problem. Therefore, when the present invention is carried out, the vicinity of the node may be supported.

As a specific configuration based on the above-described principle, an apparatus for generating ultrasonic vibrations on a rotating shaft according to the invention of claim 1 is provided.
(See FIG. 1) In an apparatus for generating ultrasonic vibration in the axial direction on the rotating shaft (7),
The wavelength of the longitudinal vibration of the ultrasonic wave in the rotation axis is λ,
The length of the rotation axis is 3λ / 2, or λ + nλ / 2 (n = 0 or greater integer),
Λ / 4 or (2n + 1) λ / 4 from both ends are rotatably supported by bearings,
A flange (10) made of a magnetic material is fixed to a location of (2n + 3) λ / 2 from the end, which hits the vibration node of the rotating shaft,
In addition, an electromagnet (11) is provided opposite to and separated from one surface of the magnetic flange, and an electromagnet (12) different from the above is provided opposite to and separated from the other surface of the magnetic flange. It is characterized by being.

The configuration of the apparatus for generating ultrasonic vibrations on the rotating shaft according to the invention of claim 2 is in addition to the configuration requirements of the invention apparatus of claim 1,
(See FIG. 3) In an apparatus for generating ultrasonic vibrations on the rotating shaft (7),
The wavelength of the longitudinal vibration of the ultrasonic wave in the rotation axis is λ,
The length of the rotation axis is 3λ / 2, or λ + nλ / 2 (n = 0 or greater integer),
The bearings (9) are rotatably supported at the locations of λ / 4 from both ends, or the locations of (2n + 1) λ / 4 from both ends, which hit the antinode of vibration,
A flange made of a magnetic material is fixed to each of λ / 2 from both ends of the rotating shaft or each of (n + 1) λ / 2 from both ends,
In addition, the electromagnet (11) is provided to be opposed to and separated from one of the magnetic flanges (10C), and is different from the above by being opposed to and separated from the other magnetic flange (10E). An electromagnet (12) is provided.

The configuration of the apparatus for generating ultrasonic vibrations on the rotating shaft according to the invention of claim 3 is in addition to the configuration requirements of the invention apparatus of claim 1 or claim 2,
A plurality of the one electromagnet (11) and the other electromagnet (12) are provided,
It is arranged along a virtual circle concentric with the rotation axis (7), or is arranged symmetrically with respect to the rotation axis.

The configuration of the apparatus for generating ultrasonic vibrations on the rotating shaft according to the invention of claim 4 is in addition to the configuration requirements of the invention apparatus of claim 1 or claim 2,
(See FIG. 2) An adapter in which a ring-shaped flange (15a) fixed to the rotary shaft (7) and an inner race receiver (15b) fitted inside the bearing (9) are integrally provided. (15) is provided,
And the drive motor (16) which rotates the said rotating shaft (7) is connected with the said adapter (15) through the coupling (14), It is characterized by the above-mentioned.

When an apparatus for generating ultrasonic vibration is applied to the rotating shaft according to claim 1,
Since the bearing and the magnetic material flange are provided at a position corresponding to the “vibration node”, the bearing and the magnetic material flange hardly vibrate.
Since the bearing does not vibrate, no audible noise is generated, and there is no possibility that the bearing will be worn out early due to vibration.
Since the amplitude of the magnetic flange is small, it is easy to accurately adjust the relative position with the electromagnet, and the adjustment state does not go wrong.
Furthermore, since the magnetic flange has a small amplitude, ultrasonic energy does not escape from the magnetic flange into the air.

When the apparatus for generating ultrasonic vibration is applied to the rotating shaft according to the second aspect, the bearing is provided at a location corresponding to the “vibration node”, so that the bearing hardly vibrates.
Since the bearing does not vibrate, no audible noise is generated, and there is no possibility that the bearing will be worn out early due to vibration.
Furthermore, since the two magnetic body flanges are respectively installed at locations corresponding to antinodes of vibration, the force of the electromagnet is effectively converted into vibration and energy efficiency is high.

When the apparatus for generating ultrasonic vibrations on the rotating shaft according to claim 3 is applied in combination with the invention of claim 1 or claim 2, a plurality of electromagnets are provided, so that strong ultrasonic vibrations are generated. It is possible,
Since the electromagnets are arranged along a circle or symmetrically, ultrasonic vibrations in the axial direction can be generated without any loss on the rotation axis without exerting an extra force on the rotation axis. it can.

  When the apparatus for generating ultrasonic vibrations on the rotary shaft according to claim 4 is applied in combination with the invention of claim 1 or claim 2, the rotational output of the drive motor cannot be applied to the vibrating rotary shaft. There is no possibility that the conductive coupling is worn early due to friction caused by vibration.

FIG. 1 shows a first embodiment of the present invention and corresponds to claim 1.
The length of the rotating shaft 7 is set to 3λ / 2. Here, λ is “propagation speed / frequency” when the generated ultrasonic wave travels as a longitudinal wave in the rotation axis. That is, the elastic length of the rotating shaft 7 is 3λ / 2.
For this reason, the rotating shaft 7 resonates at 3λ / 2 with respect to the ultrasonic wave, and its waveform is as indicated by a curve W.

For convenience of explanation, the rotary shaft 7 is divided into λ / 4 and named A to G as shown in the figure.
Locations B and F of λ / 4 from both ends of the rotating shaft 7 correspond to vibration nodes. This part is supported rotatably by a bearing 9. Since the vibration node can be considered to be locally stationary, vibration is not transmitted to the bearing 9.
This
I. Does not adversely affect the durability of the bearing and does not generate noise.
B. The ultrasonic vibration does not escape to the bearing 9. For this reason, the generated ultrasonic energy is not attenuated and can be used effectively.
The detailed structure in the vicinity of the portion where the rotating shaft 7 is supported by the bearing 9 and surrounded by the chain line ellipse will be described in detail later with reference to FIG.

A flange 10 made of a magnetic material is fixed to a position 3D / 4 from both ends of the rotating shaft 7 (D).
Since the length of the rotating shaft 7 is 3λ / 2, the central portion D hits a vibration node.
The magnetic flange 10 according to the present invention is installed at a vibration node or abdomen. In the first embodiment illustrated in FIG. 1, the vibration node is installed. In the second embodiment shown in FIG. 2, which will be described later, it is installed on the vibration belly.

In the first embodiment, two magnetic flanges 10 are fixed in close proximity to each other at a location D where the vibration is applied, and the electromagnet 11 and the same are separated from each other on both sides of each magnetic flange 10. 12 is installed.
When the electromagnets 11 and 12 are connected to the ultrasonic vibration oscillation circuit S and an ultrasonic cycle current is supplied, the electromagnets alternately generate an intermittent magnetic attractive force of the ultrasonic cycle. This force is applied to the rotating shaft 7, and the rotating shaft vibrates ultrasonically.

In order to generate a large magnetic attractive force with a small, small current electromagnet, it is effective to reduce the gap size. When the magnetic body flange 10 is installed at the vibration node as in this example, the magnetic body flange itself does not vibrate apparently, so that it is easy to set and adjust the gap size with the electromagnet.
The fact that the magnetic body flange 10 itself does not vibrate clearly has the advantage that it is difficult to transmit ultrasonic vibrations to the surrounding air.
Ultrasound is inaudible, but it may be uncomfortable depending on the cycle, so it is preferable not to transmit air. Furthermore, although it is slight, it is also an advantage of the first embodiment (corresponding to claim 1) that the ultrasonic energy does not escape into the surrounding air.

A plurality of the electromagnets 11 and 12 are arranged for each magnetic flange 10.
The minimum number of the plurality is two, but it is desirable that the number is as large as three or four.
The plurality of electromagnets 11 and 12 are arranged along a circle concentric with the axis X of the rotating shaft 7.
As a result, the forces of the plurality of electromagnets are balanced to form a pure X-axis direction resultant, and ultrasonic vibrations in the X-axis direction can be generated purely.
For the same reason, instead of arranging the plurality of electromagnets along the concentric circles, they may be arranged symmetrically with respect to the axis X, and the same effect (balance of electromagnetic force) can be obtained.

In Japanese Patent Application Laid-Open No. 2003-145395 cited as Patent Document 1, the inventor stated in paragraph No. 0003 that “the most important thing is that the ultrasonic vibration is transmitted to the grinding tool in complete agreement with the axial direction. It is an issue ”. This is exactly the case, and is highly regarded as a manifestation of the inventor's savings.
Thus, in the present invention, this problem is completely solved by a simple configuration in which the electromagnets 11 and 12 are arranged concentrically with the axis of the rotary shaft 7 or arranged symmetrically with respect to the axis. Is.
Considering the above configuration and operation, if there are a large number of electromagnets installed, they can be distributed along a plurality of circles without necessarily being arranged along one circle. The same effect can be obtained.

In the first embodiment (FIG. 1), points B, D, and F are vibration nodes, and points A, C, E, and G are vibration nodes.
When the grindstone 8 is attached to the point G which is the antinode of the vibration and the rotary shaft 7 is driven to rotate, the grindstone 8 is ultrasonically vibrated in the axial direction while rotating in the circumferential direction, and a good finished surface roughness is obtained. Can be obtained.
In order to drive the rotation around the axis with respect to the rotating shaft 7 that is ultrasonically vibrated in the axial direction as described above, the following measures are required.

In the same way as the point D where the magnetic flange 10 is fixed is a vibration node, the rotary shaft 7 is supported at the point B which is the vibration node, and the rotation output of the drive motor 16 is applied to the rotation shaft. Be transmitted. FIG. 2 shows a detailed enlargement of the vicinity surrounded by a chain line ellipse in FIG.
Reference numeral 15 indicates an adapter, which is configured as follows.
A narrow ring-shaped flange 15 a is disposed at the vibration node B and fixed to the rotary shaft 7. An inner race receiver 15b is integrally provided on the outer peripheral side of the flange 15a.

The bearing 9 has a width W of a corresponding dimension. In comparison, the vibration node B is extremely narrow in the X-axis direction (theoretically, the length in the X-axis direction is zero). When the bearing 9 is fitted in the area of the width W so as to cover this node, friction is generated between the rotating shaft 7 and the bearing 9 to wear the fitting surface or attenuate the vibration.
Therefore, in the present embodiment, a flange 15a that is thin enough to assume that the width in the X-axis direction is zero is fixed to the rotary shaft 7, and
The inner race of the bearing 9 was stably supported by the inner race receiver 15b having a width of the dimension W in the axial center X direction.

Furthermore, the following coupling 14 is interposed between the drive motor 16 and the adapter 15, and the rotary shaft 7 is rotationally driven without being affected by ultrasonic vibration.
In the coupling 14, a plurality of drive bars 14b in the X-axis direction are implanted in a disc-like disk 14a concentric with the X-axis.
The tip of the drive bar 14 b is slidably fitted to the inner race receiver 15 b of the adapter 15.

FIG. 3 shows a second embodiment of the present invention, and the differences from the first embodiment shown in FIG. 1 are as follows.
The magnetic body flange 10 in FIG. 1 is disposed at the node D of ultrasonic vibration related to the rotation axis.
The magnetic body flanges in FIG. 3 are arranged one by one at two locations C and E that hit the antinode of ultrasonic vibration.
These magnetic body flanges are members similar to the magnetic body flange 10 in FIG. 1, but for convenience of explanation, the magnetic body flange located at the vibration antinode C is denoted by reference numeral 10 </ b> C and located at the vibration antinode E. The magnetic flanges are distinguished by attaching a reference numeral 10E.

The electromagnet 12 is disposed so as to face and separate from the two magnetic body flanges 10C and 10E.
In this example, the electromagnet 11 is arranged inside the magnetic flange 10C, and the electromagnet 12 is arranged inside the magnetic flange 10E.
Although illustration is omitted, the electromagnets 11 and 12 may be arranged outside the two magnetic flanges 10C and 10E.

  In any case, the phase of the ultrasonic vibration oscillator is adjusted so that the magnetic attractive force on the magnetic flange 10C and the magnetic attractive force on the magnetic flange 10E cooperate without canceling each other. If comprised in this way, since the magnetic attraction force of an ultrasonic cycle will act with respect to the antinode of ultrasonic vibration, the given magnetic energy will be effectively converted into ultrasonic vibration energy.

When considered with reference to FIGS. 1 and 3, the following basic structure is understood.
A. The part that hits the vibration node is rotatably supported by a bearing.
B. A magnetic flange is fixed to a place where the vibration node or abdomen is hit.
C. Both ends of the rotating shaft are antinodes of vibration (however, this is the principle of elastic column vibration, not a phenomenon that was intentionally established).
In order to satisfy the above conditions, the embodiment of FIG. 1 (corresponding to claim 1) and the embodiment of FIG. 2 (corresponding to claim 2) both have the length of the rotating shaft set to 3λ / 2. It is set.

In order to satisfy the above conditions, the length of the rotating shaft is not necessarily 3λ / 2, but 3λ / 2 is the most convenient for creating a practical ultrasonic vibration tool. In the second embodiment, the length of the rotating shaft 7 is 3λ / 2. However, the length of the rotating shaft can be set to λ, 2λ, or 5λ / 2 depending on the relationship between the frequency of the ultrasonic wave used and the size of the ultrasonic tool to be configured.
In summary, the elastic length L of the rotating shaft is
L = λ + nλ / 2 (1)
It is represented by However, N is an integer greater than or equal to 0.

The above equation (1) is
L = λ (n + 2) / 2 (2)
It can also be modified.
The length of L = 3λ / 2 of the rotating shaft 7 in the first embodiment and the second embodiment is a numerical value when n = 1 is substituted into the formula (1) or the formula (2). .

As discussed above, as a modification of the length 3λ / 2 of the rotation shaft in the embodiment of FIG. 1, the value of n is arbitrarily set using the rotation shaft of the above formula (1) or formula (2). Even if set, it belongs to the technical scope of the present invention.
The above equations (1) and (2) can be applied not only to the ultrasonic region but also to the audible frequency region.
Therefore, the present invention can generate vibrations in the audible frequency region, and generating vibrations in the audible frequency region is also within the technical scope as an application example of the present invention.
When the length of the rotating shaft is set to nλ / 2 + λ, the place where the rotating shaft 7 is supported by the adapter 15 and the bearing 9 is the position of the vibration node, that is, the position of λ / 4 from the both ends, or (2n + 1) λ / 4. It becomes. However, in a normal case, it is desirable to support λ / 4, which is the node closest to both ends.

When the length of the rotation shaft in the first embodiment shown in FIG. 1 is shortened from 3λ / 2, that is, n of nλ / 2 + λ is set to 0, an attempt is made to configure a rotation shaft of length λ.
There is no place (vibration node) where the magnetic flange 10 is installed.
Therefore, the length of the rotating shaft 7 in the first embodiment must be set to 3λ / 2 or more.

When the length of the rotating shaft in the first embodiment shown in FIG. 1 is extended beyond 3λ / 2,
That is, when n of nλ / 2 + λ is 2 or more,
The location (node of vibration) where the magnetic flange 10 is installed is a location that is an integral multiple of λ / 2 from both ends.
In this case, three or more magnetic flanges can be provided. However, it is not always necessary to increase the number of magnetic flanges.
Further, if the length of the rotating shaft is extended as compared with the embodiment of FIG. 1, the number of vibration nodes increases (the number of vibration nodes appears by the number n). You can also.
Even if three or more places are supported by bearings, they belong to the technical scope of the present invention. However, it is not always necessary to increase the number of bearings.

When the length of the rotation shaft in the second embodiment shown in FIG. 3 (corresponding to claim 2) is shortened from 3λ / 2, that is, n is nλ / 2 + λ, and the rotation is λ If you configure the axis,
The location (node of vibration) where the magnetic body flange 10 is installed is the location of λ / 2 from both ends, that is, the center of the rotating shaft.
For this reason, when it is desired to configure the rotation axis as short as possible at a given ultrasonic frequency, the embodiment of FIG. 2 (corresponding to claim 2) is more preferred than the embodiment of FIG. 1 (corresponding to claim 1). Is more advantageous.

When the length of the rotating shaft in the second embodiment shown in FIG. 3 is longer than 3λ / 2, that is, when n of nλ / 2 + λ is 2 or more,
Locations (vibration nodes) where the magnetic body flange 10 is installed are locations that are integral multiples of λ / 2 from both ends (vibration nodes appear for the number n). Therefore, the number of magnetic flanges installed can be three or more.
When the number of magnetic flanges installed is three or more, the electromagnets are installed so as to face and separate from the respective magnetic flanges.

The figure which added the vibration chart to the typical sectional drawing which drawn the 1st embodiment corresponding to the composition of claim 1 of the present invention. Enlarged detail of the vicinity of the bearing and drive motor shown in FIG. FIG. 5 is a diagram in which a vibration diagram is added to a schematic cross-sectional view depicting a second embodiment corresponding to claim 2 of the present invention; Sectional drawing of the ultrasonic vibration apparatus disclosed by Unexamined-Japanese-Patent No. 2003-145395 which concerns on patent document 1

Explanation of symbols

DESCRIPTION OF SYMBOLS 3 ... Spindle main body 3b ... Main body sleeve 4 ... Ultrasonic vibrator 6 ... Supporting horn 6d ... Buffer sleeve 6e ... Circumference flange 6f ... Shaft contact flange 6g ... Buffer groove 7 ... Rotary shaft 8 ... Grinding wheel 9 ... Bearing 10 ... Magnetic body Flange 10C ... Magnetic body flange 10E ... Magnetic body flange 11 ... Electromagnet 12 ... Electromagnet 14 ... Coupling 14a ... Disk 14b ... Drive bar 15 ... Adapter 15a ... Flange 15b ... Inner race receiver 16 ... Drive motor 16
A: Ultrasonic vibration antinode of rotating shaft B ... Ultrasonic vibration node of rotating shaft C ... Ultrasonic vibration node of rotating shaft D ... Ultrasonic vibration node of rotating shaft E ... Antinode of ultrasonic vibration of rotating shaft F: Node of ultrasonic vibration of the rotating shaft G ... Antinode of ultrasonic vibration of the rotating shaft M ... Motor S ... Ultrasonic vibration oscillation circuit W ... Bearing width X: Shaft axis

Claims (4)

In a device that generates ultrasonic vibrations on the rotating shaft,
The wavelength of the longitudinal vibration of the ultrasonic wave in the rotation axis is λ,
The length of the rotation axis is 3λ / 2, or λ + nλ / 2 (n = 0 or greater integer),
Λ / 4 or (2n + 1) λ / 4 from both ends are rotatably supported by bearings,
A flange made of a magnetic material is fixed in the vicinity of (2n + 3) λ / 2 from both ends of the rotating shaft,
In addition, an electromagnet is provided opposite to and separated from one surface of the magnetic flange, and an electromagnet different from the above is provided opposite to and separated from the other surface of the magnetic flange. A device that generates ultrasonic vibrations on the rotating shaft. In a device that generates ultrasonic vibrations on the rotating shaft,
The wavelength of the longitudinal vibration of the ultrasonic wave in the rotation axis is λ,
The length of the rotation axis is 3λ / 2, or λ + nλ / 2 (n = 0 or greater integer),
Each of the λ / 4 locations from both ends, or (2n + 1) λ / 4 locations are rotatably supported by bearings,
A flange made of a magnetic material is fixed to the vicinity of λ / 2 from both ends of the rotating shaft, or to the vicinity of (n + 1) λ / 2 from both ends,
In addition, an electromagnet is provided to be opposed to and separated from one of the magnetic flanges, and an electromagnet different from the above is provided to be opposed to and separated from the other magnetic flange. A device that generates ultrasonic vibrations on the rotating shaft. A plurality of the one electromagnet and the other electromagnet are provided,
3. The apparatus for generating ultrasonic vibrations on a rotating shaft according to claim 1, wherein the rotating shaft is arranged along a circle concentric with the rotating shaft or arranged symmetrically with respect to the rotating shaft. . An adapter is provided in which a ring-shaped flange fixed to the rotating shaft and an inner race receiver that fits inside the bearing are continuously provided.
The apparatus for generating ultrasonic vibrations on the rotating shaft according to claim 1 or 2, wherein a drive motor for rotating the rotating shaft is connected to the adapter via a coupling. .

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