Electrical generator or motor structure – Non-dynamoelectric – Piezoelectric elements and devices
Reexamination Certificate
2002-04-01
2004-07-13
Dougherty, Thomas M. (Department: 2834)
Electrical generator or motor structure
Non-dynamoelectric
Piezoelectric elements and devices
C310S325000, C310S323080, C310S323120, C310S323130
Reexamination Certificate
active
06762535
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a spindle structure in an ultrasonic machine which can perform grinding work, cutting work or the like on a workpiece with a high degree of accuracy and efficiency while applying ultrasonic vibration to various working tools.
2. Description of the Related Art
In a field of precision working of a member to be difficult to be worked, such as a highly hard brittle material, a metal composite material or the like, an ultrasonic machine is used as cutting working or boring working means. The ultrasonic machine is generally provided with a spindle rotationally driven by a motor, an ultrasonic vibrator arranged coaxially to the spindle, a horn connected to the ultrasonic vibrator integrally therewith, and a working tool, such as a cutting tool, a grinding tool or the like, which is mounted on the tip end of the horn, in which an ultrasonic vibration system is fixed in a high-rigid state.
In such an ultrasonic machine, in order to maintain preciseness capable of precision working, it is necessary to maintain the assembling precision of the spindle, the ultrasonic vibrator and the horn in a severe and high-rigid state. In addition, the most important object in designing is to make ultrasonic vibration applied by the ultrasonic vibrator completely coincide with the axial direction and to transmit the vibration to a machining tool with a constant amplitude of the vibration.
The present applicant has developed a spindle structure in an ultrasonic machining where ultrasonic vibration can be transmitted to a working tool for cutting work or grinding work without wobbling around a rotating shaft and with high efficiency, and cutting work or grinding work can be performed with extreme accuracy, and such a spindle structure has been disclosed in Unexamined Japanese Patent Publication No. 2000-254801.
FIG. 9
is a partial sectional view showing a spindle structure of an ultrasonic machine disclosed in the above publication. As shown in
FIG. 9
, the spindle structure is provided with a spindle
63
rotationally driven around an axial line thereof, an ultrasonic vibrator
64
housed in a hollow main body sleeve
63
b
formed in the spindle
63
, two supporting horns
66
,
67
connected coaxially to the ultrasonic vibrator
64
and fixed to an inner peripheral wall of the main body sleeve
63
b
in a constraining manner, a holder horn
65
whose proximal end is connected coaxially to the supporting horns
66
,
67
and whose distal end is attachable to a cutting tool
68
, and the like.
Also, the supporting horns
66
,
67
comprise main bodies
66
a
,
67
a
arranged coaxially to the ultrasonic vibrator
64
, base portions
66
c
,
67
c
integrally formed at intermediate portions, in axial directions, of the main bodies
66
a
,
67
a
, elastically deformable cylindrical thin damping sleeves
66
d
,
67
d
formed coaxially to the base portions
66
c
,
67
c
around the main bodies
66
a
,
67
a
, and flanges
66
e
,
66
f
,
67
e
,
67
f
formed on both ends of the damping sleeves
66
d
,
67
d
in their axial directions.
These supporting horns
66
,
67
are provided inside the main body sleeve
63
b
of the spindle
63
in a state where they have close contact to each other, and the flanges
66
e
,
66
f
,
67
e
,
67
f
are fixed into the inner peripheral wall of the main body sleeve
63
b
. A spacer member (not shown) may be disposed between the flanges
66
e
and
66
f
,
66
f
and
67
e
, and
67
e
and
67
f
, respectively.
By employing such a spindle structure, ultrasonic vibration transmitted from the ultrasonic vibrator
64
to the main bodies
66
a
,
67
a
of the supporting horns
66
,
67
are transmitted to the holder horn
65
side as they are. On the other hand, since the transmission to the spindle
63
is buffered by the damping sleeves
66
d
,
67
d
, the leak of ultrasonic vibration energy to the spindle
63
is suppressed. Thus the vibration transmission rate to the holder horn
65
can be kept high, while working accuracy can be significantly improved by maintaining the spindle
63
, which is a main rotation shaft, and the holder horn
65
on the same axis.
In the spindle structure shown in
FIG. 9
, it is necessary to arrange, inside the main body sleeve
63
b
, the members such as the supporting horns
66
,
67
and the spacers (not shown) in a state where they have close contact to each other without any gap therebetween, thereby restraining the members in both axial and peripheral directions of the spindle
63
. In addition, the members should be assembled so as not to introduce any strain or concentrated stress on any member. Therefore, during the assembly process, it is necessary to precisely adjust the position and attitude of the respective members with the utmost care by watching to confirm that there is no gap between adjacent members upon every assembly of one member. This requires not only the skill and technique of the worker but also a vast number of assembling steps. Moreover, since a plurality of supporting horns, that is, the supporting horns
66
,
67
, are arranged to be in close contact with each other, core wobbling after assembly due to uneven size accuracy of the members cannot be avoided even when the members have been assembled with great care, which leads to poor machining accuracy.
Additionally, since the flanges
66
e
,
66
f
,
67
e
,
67
f
of the supporting horns
66
,
67
are fixed into the inner peripheral wall of the main body sleeve
63
b
, a part of the ultrasonic vibration transmitted from the ultrasonic vibrator
64
to the main body
66
a
,
67
a
of the supporting horns
66
,
67
may leak through the members such as the flanges
66
e
,
66
f
,
67
e
,
67
f
to the main body sleeve
63
b
to generate heat. In this regard, owing to the relatively large total length of the members such as the supporting horns
66
,
67
coaxially connected, any deformation by the heat generation increases and, therefore, easily causing rolling of the cutting tool
68
, which results in degradation of machining accuracy.
An object of the present invention is to provide a spindle structure of an ultrasonic machine capable of reducing the number of assembling steps and improving machining accuracy as well as a supporting horn used in the same.
SUMMARY OF THE INVENTION
A spindle structure of an ultrasonic machine according to the present invention comprises a spindle main body rotationally driven around an axial line thereof, an ultrasonic vibrator housed in a cylindrical main body sleeve formed in the spindle main body, and a supporting horn connected to the ultrasonic vibrator within the main body sleeve, wherein the supporting horn comprises a main body connected coaxially to the ultrasonic vibrator, a base portion formed in a brim shape on an outer peripheral face of the main body, an elastic cylindrical damping sleeve formed by extending an outer periphery of the base portion in the axial direction, a loose flange formed on one end of the damping sleeve, a fixing flange formed on the other end of the damping sleeve, and a gap portion formed on an outer peripheral face of the base portion along a circumferential direction thereof, the loose flange of the supporting horn being disposed on the side of the ultrasonic vibrator in a state that the loose flange is slidable to and has contact with an inner peripheral face of the main body sleeve and the fixing flange being mounted on the main body sleeve in such a state that the fixing flange is restrained in the axial direction. Here, the term “loose flange” means a flange which is restrained only in a diametrical direction by making an outer peripheral portion of the flange abut another member, and the term “fixing flange” means a flange which is restrained at least in the axial direction by making a face of the flange crossing in its axial direction abut another member. The term “gap portion” means a portion where continuity of an outer peripheral face is interrupted, for example, a portion where a hole, a groove, a sl
Kawanami Masayoshi
Take Yoshihiro
Jordan and Hamburg LLP
Takesho Co., Ltd.
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