U.S. patent application number 09/987441 was filed with the patent office on 2002-05-16 for cooler for machine tool.
Invention is credited to Hara, Mitsugu.
Application Number | 20020056279 09/987441 |
Document ID | / |
Family ID | 18820637 |
Filed Date | 2002-05-16 |
United States Patent
Application |
20020056279 |
Kind Code |
A1 |
Hara, Mitsugu |
May 16, 2002 |
Cooler for machine tool
Abstract
A less expensive cooler for a machine tool comprises a main
spindle (3), a housing (1) rotatably supporting the main spindle
(3) via bearing (2), and a tube (11) wound around the housing (1)
for passing a cooling mist therethrough.
Inventors: |
Hara, Mitsugu;
(Kishiwada-shi, JP) |
Correspondence
Address: |
ARMSTRONG,WESTERMAN & HATTORI, LLP
1725 K STREET, NW.
SUITE 1000
WASHINGTON
DC
20006
US
|
Family ID: |
18820637 |
Appl. No.: |
09/987441 |
Filed: |
November 14, 2001 |
Current U.S.
Class: |
62/62 |
Current CPC
Class: |
B23Q 11/127
20130101 |
Class at
Publication: |
62/62 |
International
Class: |
F25D 025/00 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 14, 2000 |
JP |
2000-346821 |
Claims
What is claimed is:
1. A cooler for a machine tool, comprising a main spindle, a
housing rotatably supporting the main spindle via a bearing, and a
channel provided in association with the housing for passing a
cooling mist therethrouqh.
2. A cooler as set forth in claim 1, wherein the channel comprises
a tube helically wound around the housing.
3. A cooler as set forth in claim 1, wherein the channel is
provided within the housing.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a cooler for a machine
tool.
[0003] 2. Desription of the Art
[0004] In conventional machine tools, a main spindle is rotatably
supported by a housing via a bearing, so that heat generated by the
rotation of the main spindle is conducted to the housing.
Therefore, a cooler for cooling the housing is provided in such a
machine tool. One example of such a cooler is the structure for
cooling a spindle unit as shown in FIG. 4 which is disclosed in
Japanese Unexamined Patent Publication No. 6-31585 (1994). The
spindle unit includes a housing 31, a spindle cylinder 32 fixed
within the housing 31, and a main spindle 33 rotatably supported in
the housing 31 via a bearing unit 34 and an upper bearing (not
shown). The cooling structure of the spindle unit includes a
cooling liquid channel defined between a helical groove 35 formed
in an outer peripheral surface of the main spindle 33 and a bearing
inner cylinder 36 of the bearing unit 34, and another cooling
liquid channel defined between a helical groove 37 formed in an
outer peripheral surface of the spindle cylinder 32 and the housing
31. In FIG. 4, the spindle unit further includes a cooling liquid
supply path 38, a cooling liquid drain path 39, a cooling liquid
inlet port 40 and a cooling liquid outlet port 41. In general, a
cooling liquid is supplied to the respective cooling liquid
channels by a cooling liquid supply unit which has an orifice for
flow rate control, a sensor for temperature control and the
like.
[0005] However, a cooling liquid supply unit specifically designed
for supplying the cooling liquid to the cooling liquid channels in
the spindle unit cooling structure is quite expensive, thereby
making the machine tool itself more expensive.
[0006] In view of the foregoing, it is an object of the present
invention to provide a less expensive cooler for a machine
tool.
SUMMARY OF THE INVENTION
[0007] In accordance with the present invention to achieve the
aforesaid object, there is provided a cooler for a machine tool,
which comprises a main spindle, a housing rotatably supporting the
main spindle via a bearing, and a channel provided in association
with the housing for passing a cooling mist therethrough.
[0008] In the inventive machine tool cooler having the main spindle
and the housing rotatably supporting the main spindle via the
bearing, the channel for passing the cooling mist therethrough is
in association with the housing. Therefore, the housing can be
cooled by passing the cooling mist through the channel in
association with the housing and taking heat away from the housing
by evaporation of the cooling mist. In addition, the cooling mist
can easily be generated with the use of a cooling liquid supply
unit and a compressed air supply unit, both typically included in
the machine tool. More specifically, a tank containing a cooling
liquid, a lubricating liquid or a mixture of the cooling liquid and
the lubricating liquid for cooling or lubricating a tool, and a
pump for supplying the cooling liquid or the like from the tank to
a cooling liquid injection nozzle typically are provided in the
machine tool as the cooling liquid supply unit. In addition, an air
compressor for supplying compressed air to eject the cooling liquid
or the like from the cooling liquid injection nozzle typically is
provided in the machine tool as the compressed air supply unit.
Therefore, the generation of the cooling mist can easily be
achieved by mixing the cooling liquid supplied from the cooling
liquid supply unit with the compressed air supplied from the
compressed air supply unit so as to produce the cooling liquid in
mist form. By thus employing the cooling liquid supply unit and the
compressed air supply unit provided in the machine tool, the need
for providing a relatively expensive cooling liquid supply unit
specifically designed for the cooling of the housing can be
obviated which thereby reduces the cost of the machine tool.
[0009] Where the channel comprises a tube helically wound around
the housing in the inventive machine tool cooler, the channel can
be formed from a less expensive tubular material.
[0010] Where the channel is provided within the housing in the
subject machine tool cooler, the housing can be cooled from its
interior with a more advantageous cooling effect.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] FIG. 1 is a sectional view illustrating a machine tool
cooler according to one embodiment of the present invention;
[0012] FIG. 2 is a sectional view illustrating a machine tool
cooler according to another embodiment of the present
invention;
[0013] FIG. 3 is a sectional view illustrating a machine tool
cooler according to further another embodiment of the present
invention; and
[0014] FIG. 4 is a sectional view illustrating a machine tool
cooler according to the prior art.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0015] Embodiments of the present invention will hereinafter be
described in detail with reference to the attached drawings.
[0016] FIG. 1 is a sectional view illustrating a cooler for a
machine tool in accordance with one embodiment of the present
invention. In this embodiment, the machine tool is a numerically
controlled (NC) lathe. In FIG. 1, a generally cylindrical housing 1
fixed to a headstock (not shown) has a center through-hole 1a, and
a pair of bearings 2 are fixed to longitudinally opposite portions
of the inner periphery of the center through-hole 1a. A generally
cylindrical main spindle 3 within through-hole 1a is rotatably
supported by the bearings 2. A chuck (not shown) is provided at one
end (a right end in FIG. 1 ) of the main spindle 3. A pulley 4 is
fixed around the other end portion (a left end portion in FIG. 1)
of the main spindle 3, and is coupled to a rotation shaft (not
shown) of a motor via a belt 5. A draw bar and the like (not shown)
are provided in the center through-hole 3a of the main spindle 3.
In FIG. 1, an annular fixture 6 is fitted around the main spindle
3.
[0017] The machine tool includes a cooling liquid supply unit (not
shown) including a tank containing a cooling water (cooling liquid)
such as tap water and a pump for supplying the cooling water from
the tank to a cooling water injection nozzle (not shown). The
machine tool further includes a compressed air supply unit (not
shown) including an air compressor for supplying compressed air to
the cooling water injection nozzle. During machining, the cooling
water and the compressed air are supplied from the cooling liquid
supply unit and the compressed air supply unit, respectively, to
the cooling water injection nozzle, so that the cooling water from
the cooling water injection nozzle is sprayed over a machining part
(including a machining surface of the tool and a machined surface
of a workpiece).
[0018] The housing 10 has a helical groove 10 formed in an outer
peripheral surface thereof, and a tube 11 such as a flexible tube
is helically wound around the housing 1 along the groove 10. One
end of the tube 11 is connected to a bifurcated connection tube 12
(one example of mist generating means), and the other end of the
tube is open to the atmosphere. The bifurcated connection tube 12
has a confluent portion 13 connected to the one end of the tube 11,
and two branch portions 14, 15 branched from the confluent portion
13. The branch portions 14 is connected to the cooling liquid
supply unit via a hose or the like, and the branch portion 15 is
connected to the compressed air supply unit via a hose or the
like.
[0019] When the cooling liquid supply unit and the compressed air
supply unit are operated in the machining of a workpiece, cooling
water is supplied from the cooling liquid supply unit to the
cooling water injection nozzle and to the branch portion 14 of the
bifurcated connection tube 12, and compressed air is supplied from
the compressed air supply unit to the cooling water injection
nozzle and to the branch portion 15 of the bifurcated connection
tube. Then, the cooling water is sprayed over the machining part
from the cooling water injection nozzle. On the other hand, the
cooling water and the compressed air respectively supplied to the
branch portions 14 and 15 merge and mix with each other in the
confluent portion 13, so that the cooling water is disintegrated
into minute water particles in a mist form. The resultant cooling
mist flows into the tube 11 helically wound around the housing 1.
The water particles of the mist evaporate while passing through the
tube 11 to cool the housing 1, and discharge from the other end of
the tube 11 into the atmosphere.
[0020] In this embodiment, the housing 1 is cooled by passing the
cooling mist through the tube 11 helically wound around the housing
1 and withdrawing heat from the housing by the evaporation of the
cooling mist. In addition, the cooling mist may be generated by
employing the cooling liquid supply unit and the compressed air
supply unit already provided in the machine tool. Although the tube
11 is required, the cooler is inexpensive since there is no need to
provide a cooling mist supply unit specifically designed for the
cooling of the housing. Further, tap water can be used as the
cooling water and, hence, even if the cooling mist passed through
the tube 11 is discharged from the other end of the tube 11 into
the atmosphere, there is no adverse influence on the environment.
Furthermore the tube 11 has a simple construction with the other
end thereof being open to the atmosphere.
[0021] FIG. 2 is a sectional view illustrating a machine tool
cooler according to another embodiment of the present invention.
This embodiment differs from the embodiment shown in FIG. 1 in that
the tube 11 is not wound around the housing 1 along the groove 10
formed in the outer peripheral surface of the housing 10, but
rather a cylindrical body 20 is fitted around the housing 1 in a
liquid tight manner so as to close the circumferential open side of
the groove 10. Thus, a helical channel 21 is defined between the
groove 10 and an inner peripheral surface of the cylindrical body
20. One end of the channel 21 is connected to a bifurcated
connection tube (mist generating means) 12 via a hose 22, and the
other end of the channel is open to the atmosphere. In this
embodiment, other components are the same as in the embodiment of
FIG. 1, and like components are denoted by like reference
characters. This embodiment has similar functions and effects as
the embodiment of FIG. 1.
[0022] FIG. 3 is a sectional view illustrating a machine tool
cooler according to a further embodiment of the present invention.
This embodiment diffes from the embodiment shown in FIG. 1 in that
a plurality of channels 25 (only one channel 25 is shown in FIG. 3)
are within the housing 1. One end of each of the channels 25 is
connected to a bifurcated connection tube (mist generating means)
12 and the other end of each of the channels 25 is open to the
atmosphere. Therefore, the tube 11 is not wound around the housing
1 along the groove 10. In this embodiment, other components are the
same as in the embodiment of FIG. 1, and like components are
denoted by like reference characters. This embodiment has similar
functions and effects as the embodiment of FIG. 1. However, the
housing 1 can be cooled from its interior with a more advantageous
cooling effect.
[0023] In the embodiments described above, the groove 10 is formed
in the outer peripheral surface of the housing 1, but the formation
of the groove 10 is not necessarily required. Further, any of
various cooling liquids and lubricating liquids may be used alone
or as a mixture instead of the cooling water in the aforesaid
embodiments. In the embodiment shown in FIG. 3, the channels 25 may
be helically formed in the housing 1.
[0024] Although the pulley 4 fixed around the other end portion of
the outer periphery of the main spindle 3 is coupled to the
rotation shaft of the motor via the belt 5 for driving the main
spindle 3 in the embodiments described above, a motor incorporating
the main spindle 3 may be employed to drive the main spindle.
[0025] The inventive machine tool cooler is applicable not only to
a numerically controlled (NC) lathe, but also to any of various
other machine tools such as machining centers and grinding
machines.
[0026] In the machine tool cooler according to the present
invention, the housing can be cooled by passing the cooling mist
through the channel provided in association with the housing which
removes heat from the housing by the evaporation of the cooling
mist. In addition, the cooling mist can easily be generated with
the use of a cooling liquid supply unit and a compressed air supply
unit typically provided in the machine tool. More specifically, a
tank containing a cooling liquid, a lubricating liquid or a mixture
of the cooling liquid and the lubricating liquid for cooling or
lubricating the tool and/or workpiece, and the pump for supplying
the cooling liquid or the like from the tank to the cooling liquid
injection nozzle typically are provided in the machine tool as the
cooling liquid supply unit, and further an air compressor for
supplying compressed air to eject the cooling liquid or the like
from the cooling liquid injection nozzle typically is provided in
the machine tool as the compressed air supply unit. Therefore, the
generation of the cooling mist easily can be achieved by mixing the
cooling liquid supplied from the cooling liquid supply unit with
the compressed air supplied from the compressed air supply unit to
produce the cooling liquid into a mist form. By thus employing the
cooling liquid supply unit and the compressed air supply unit
already provided in the machine tool, the need for providing a
relatively expensive cooling liquid supply unit specifically
designed for the cooling of the housing can be obviated thereby
reducing the cost of the machine tool.
[0027] Where the channel comprises a tube helically wound around
the housing in the inventive machine tool cooler, the channel can
be formed from an inexpensive tubular material.
[0028] Where the channel is provided within the housing in the
inventive machine tool cooler, the housing can be cooled from its
interior with a more advantageous cooling effect.
* * * * *