U.S. patent number 3,859,876 [Application Number 05/371,855] was granted by the patent office on 1975-01-14 for cutting device for an ultrasonic vibration system.
This patent grant is currently assigned to Citizen Watch Co., Ltd.. Invention is credited to Akio Jindai, Masami Shimizu.
United States Patent |
3,859,876 |
Shimizu , et al. |
January 14, 1975 |
CUTTING DEVICE FOR AN ULTRASONIC VIBRATION SYSTEM
Abstract
A cutting device for an ultrasonic vibration system comprises an
elongated tool having a cutting edge formed on the front end
thereof, and a torsional transducer attached to the tool body at a
nodal point of vibration thereof, as well as, if necessary, an
amplifier horn is positioned between the tool body and transducer,
so that the torsional transducer serves to apply an elastic
vibration to the tool body. SPECIFICATION The present invention
relates to a cutting device for an ultrasonic vibration system
mainly used in a lathe and having a cutting tool elastically
vibrated in a cutting direction. It has been well known that
ultrasonic vibration can be applied to a cutting tool body in a
cutting operation so as to reduce the cutting resistance and
thereby obtain a product having a smooth surface and prolong the
tool life. FIG. 1 indicates an ultrasonic vibrator for a prior-art
cutting device operative with bending vibration as one of several
systems using longitudinal vibration, torsional vibration or
bending vibration. In this case, a longitudinal vibration generated
by means of a transducer 12 is amplified by a horn 13 and applied
to a point located at the center of a vibration wave defined for a
cutting tool body 11 as shown in FIG. 1, and at which the horn 13
is coupled to the tool body 11. The tool body 11 is supported by
setting pins attached thereto at two nodal points of vibration and
undergoes transverse vibration on a neutral plane 17 on which are
positioned the nodal points of vibration, so as to vibrate a chip
15 in a cutting direction as the cutting edge of said chip 15,
which is attached to the front end of the tool body 11, engages the
surface of a workpiece 16 rotated. Since the longitudinal vibration
of the transducer involved in this cutting device must be directed
parallel to a direction to which the cutting edge of the chip is
vibrated, such an ultrasonic vibration system can not be used in an
automatic lathe having a plurality of tools 21 to 25 positioned as
illustrated in FIG. 2, because the cutting device does not have
space sufficient to allow the transducer to be installed between
the tool bodies. An object of this invention is to provide a
cutting device using an ultrasonic vibration system for an
automatic lathe as mentioned above, even if the cutting device only
has a slight space between tool bodies. The cutting device of this
invention is provided with a torsional transducer attached to the
side of a tool body, preferably via an amplifier horn, so that the
torsonal transducer serves to apply a transverse vibration to the
tool body. The torsional transducer relative to this invention can
be adapted to the automatic lathe as indicated by reference numbers
26 to 30 in FIG. 2 wherein the transducers 26 to 30 are attached to
the tool bodies 21 to 25 in a manner so as extended in a direction
perpendicular to a plane of the paper.
Inventors: |
Shimizu; Masami (Tokyo,
JA), Jindai; Akio (Tokyo, JA) |
Assignee: |
Citizen Watch Co., Ltd. (Tokyo,
JA)
|
Family
ID: |
13214446 |
Appl.
No.: |
05/371,855 |
Filed: |
June 20, 1973 |
Foreign Application Priority Data
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Jun 23, 1972 [JA] |
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47-62929 |
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Current U.S.
Class: |
82/158; 82/904;
29/DIG.46 |
Current CPC
Class: |
B23B
29/125 (20130101); Y10S 82/904 (20130101); Y10T
82/2585 (20150115); Y10S 29/046 (20130101) |
Current International
Class: |
B23B
29/00 (20060101); B23B 29/12 (20060101); B23b
029/04 () |
Field of
Search: |
;82/DIG.9,36R,36A
;51/59SS ;29/DIG.46,96 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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|
|
|
|
602,801 |
|
Jun 1948 |
|
GB |
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1,087,440 |
|
Feb 1955 |
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FR |
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Primary Examiner: Meister; J. M.
Assistant Examiner: Briggs; W. R.
Attorney, Agent or Firm: Montague; Ernest G. Ross; Karl F.
Dubno; Herbert
Claims
We claim:
1. A cutting device in an ultrasonic vibration system
comprising:
an elongated tool body having a symmetry plane through the center
of said body;
means forming a cutting edge at a front end of said body
substantially at said plane;
means for mounting said body so that the natural transverse bending
vibration mode of said body has nodal points lying in said plane
whereby said plane coincides with the neutral plane of vibration of
said body;
a torsional transducer operatively coupled to said body with its
axis of torsional vibration lying in said plane and transverse to
the longitudinal extension of said body at one of said nodal
points; and
an amplifier horn interposed between said body and said transducer
to transmit bending vibration from said transducer to said
body.
2. The cutting device defined in claim 1 wherein a plurality of
such transducers and respective amplifier horns are provided at
respective nodal points along said body.
3. The cutting device defined in claim 1 wherein said body has a
front end portion of a thickness thinner than that of the rest of
said body so as to increase the amplitude of said cutting edge in a
direction transverse of said body.
Description
The features and advantages of this invention will become more
readily apparent from the following detailed description with
reference to the accompanying drawing, in which:
FIG. 1 is a side view of a cutting device according to the prior
technique;
FIG. 2 is a front view of an automatic lathe using an ultrasonic
vibration system according to this invention;
FIG. 3 is a perspective view of a cutting device of an ultrasonic
vibration system embodying this invention;
FIG. 4 is a side view of the cutting device of FIG. 3; and
FIGS. 5 and 6 are exaggerated side views of the prior cutting
device wherein the action of the tool and workpiece is more clearly
illustrated.
The cutting device illustrated in FIGS. 2 to 4 comprises a tool 31
having a bar-shaped body 31a and a chip 35 mounted on the front end
of the tool body 31a, and a torsional transducer 32 of convenient
type which comprises a cylindrical ferrite core, a coil 40 attached
to the core, and a ferrite pole 41 inserted through the assembly of
the core and coil. The cutting device preferably involves an
amplifier horn 33 connected with the ferrite core and attached to
the side of the tool body 31a by soldering or means of threaded
screws. The attaching position of the horn 33 to the tool body
should be a nodal point of vibration of the tool body. Though the
transducer 32 is here connected through the horn with the tool
body, it may be connected directly with the tool body at a nodal
point of vibration. The cutting tool 31 has two set pins 34 in
order to set the tool body 31a to a tool holder (not shown). The
set pins 34 are attached to the tool body 31a at the nodal points
of vibration of the tool body. The pins may be fixed to the side of
the tool body, although we prefer to pivot the tool body with the
pin end rotatably inserted into a journal bore formed in the tool
body side and if necessary, to lubricate it by a graphite or
molybdenum disulfide.
In the cutting operation, the turning center of a workpiece 36
preferably agrees with and is aligned with or lies in a neutral
plane 37 of the nodal points of vibration and the cutting edge of
the chip 35.
The chip 15 of the prior cutting tool as shown in FIG. 1 is
attached to the front end of the tool body with its cutting edge
parallel to a central plane 17 apparently defined to the middle
portion of the tool width and deviating slightly from a true
neutral plane 17'. Accordingly, the cutting edge of the prior
cutting tool is vibrated with an error angle to a tangential
direction of the rounded surface of the workpiece 16, because a
quantity of the tool body is distributed asymmetrically to the
central plane by the cutting chip being one-sided, whereby the
cutting edge is really vibrated in a direction indicated in FIG. 5
by an arrow line 18. In this case, in order to compensate for the
vibrating direction of the cutting edge, the workpiece must be
adjusted to a position as indicated in FIG. 5 by a dotted line 16',
or the tool body must be inclined as illustrated in FIG. 6 so as to
align the vibrating direction of the tool with the tangential
direction of the workpiece. Nevertheless, such compensation is
unsighted and very difficult to perform.
In contradistinction with the above-mentioned prior technique, the
cutting tool of this invention has a cutting edge effectively
vibrated for an elongated amplitude as illustrated in FIG. 4 by a
reference number 39, because the front end portion 38 of the tool
body is made in a thickness thiner than that of the other portion
of the tool body. Of course, the top end portion 38 may be made
with a width narrower than that of the other portion of the tool
body. Such a cutting tool results in improved cutting speed.
Furthermore, though the vibration of the cutting edge is generally
damped due to the cavitation generated as cutting oil supplied to
the cutting edge avoidably flows to the supported portion of the
tool body ("cavitation" in this case means that the vibration of
the solid member is damped by liquid vaporized in expansion as the
liquid material is brought into contact with the solid member under
ultrasonic vibration so as to produce the vacuum space between both
materials.). The cutting tool of this invention as shown in FIGS. 3
and 4 conveniently includes a stepped form which prevents the
flowing of the cutting oil toward the based portion of the tool
body, so that the effective vibration of the cutting edge is
maintained.
This invention also contemplates the use of a plurality of
torsional transducers which, though not shown in the drawing, are
attached to the tool body at nodal points of vibration, if
necessary, via a plurality of horns.
* * * * *