Heat exchange – Movable heating or cooling surface – Rotary drum
Reexamination Certificate
2000-03-09
2002-02-05
Atkinson, Christopher (Department: 3743)
Heat exchange
Movable heating or cooling surface
Rotary drum
C165S086000, C165S089000, C165S087000, C165SDIG001, C429S047000
Reexamination Certificate
active
06343644
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a hollow screw cooling device and, more particularly, to a hollow screw cooling device that is easy to maintain and assemble.
2. Description of the Prior Art
The hollow screw is frequently used as the feed apparatus in high speed rotating machine such as the machining center. The hollow screw in the prior art is disclosed, for example, as the H-shaped hollow screw produced by NSK Ltd. The main structure of the hollow screw is shown in FIG.
4
. Each end of the screw
90
is supported by a bearing device
91
. The screw is driven to rotate by a driving source such as a servo motor and drives a table
93
fixed on a screw nut
92
to have linear reciprocal motion.
To follow the trend of high speed feed, the inner portion of the screw
90
is hollow. Coolant is forced to circulate within the screw
90
by, for example, a pump so as to bring out heat generated during high speed operation. A conduit
94
of a proper length is provided along the axial direction within the hollow screw
90
. One end of the conduit
94
connects to a coolant inlet formed on one end of the screw
90
; the other end connects to a coolant outlet
95
formed on the driven end of the screw
90
. The coolant outlet
95
is fixed on an oil-proof base
96
on the inner side of the bearing device
91
over the driven end of the screw
90
and connects to the conduit
94
through a cross pipe
97
.
A rubber seal
98
in close contact with the screw
90
is provided within the oil-proof base
96
. The seal
98
is likely to get vulcanized after a certain period of use or damaged due to friction under high rotating speed, thus it has to be maintained or replaced periodically. Since the oil-proof base
96
is mounted on the inner side of the bearing device
91
on the driven end, the bearing device
91
on the driven end has to be taken off first so that the oil-proof base
96
can be disassembled to take off the seal
98
for maintenance or replacement. This process is very complicated and time-consuming, and a high precision adjustment has to be performed on the screw
90
again after putting back the bearing device
91
. So the maintenance and replacement of the seal
98
require a technician skilled in the art spending a long time to finish the job. This does not only affect the efficiency of the machining center but also is not economical at all.
In view of the foregoing drawbacks of the hollow screw in the prior art, the inventor made efforts to modify and improve the structure and, after many years of hard working and researches, finally came up with the hollow screw cooling device.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a hollow screw cooling device, which does not need to take off components such as the bearing and being device while maintaining and replacing the seal. The maintenance operation is fairly simple and fast. Furthermore, there is no need to perform a high precision adjustment on the screw after putting back the seal and the oil-proof base. This maintenance operation can be done by ordinary staff, which greatly saves costs in human power and time.
Another object of the present invention is to provide a hollow screw cooling device, wherein a seal is installed on the end with a smaller diameter of the screw. The radius of the seal decreases. The angular speed of the rotating seal also decreases as the radius diminishes. Therefore, the abrasion of the seal can be slower while the seal lifetime can be elongated. At the same time, fewer seal maintenance and replacements are needed.
Moreover, the present invention provides a hollow screw cooling device, which has a fall cooling effect on the bearing device and bearing and elongates its lifetime.
The hollow screw cooling device achieving the above objects has a set of apertures formed on the oil-proof base. The base is fixed on the outer side of a bearing press board by screws going through the apertures and the through holes on the bearing press board. By taking off the fixing screws, the oil-proof base can be directly separated from the bearing device for seal maintenance and replacement without the need to disassemble other components such as the bearing and bearing device.
REFERENCES:
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patent: 3310836 (1967-03-01), Nichols
patent: 3477500 (1969-11-01), Sear
patent: 3583687 (1971-06-01), Nakahara
patent: 3946803 (1976-03-01), Hertzer et al.
patent: 3989101 (1976-11-01), Manfredi
patent: 4059777 (1977-11-01), Whiteley
patent: 4073338 (1978-02-01), Fujikake et al.
patent: 4582128 (1986-04-01), Jarreby
patent: 4986345 (1991-01-01), Vemura et al.
patent: 5778971 (1998-07-01), Szam
patent: 5843282 (1998-12-01), Schmitt et al.
patent: 6186755 (2001-02-01), Haga
patent: 6203072 (2001-03-01), Berghuis et al.
patent: 0001451 (1979-01-01), None
Huang Horng-Chieh
Lin Chi-Chen
Lin Ching-Yuan
Tsai Kun-Lung
Atkinson Christopher
Industrial Technology Research Institute
Rabin & Berdo P.C.
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