Note: Descriptions are shown in the official language in which they were submitted.
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NSK 281
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1 Lubricant Supplying Apparatus
BACKGROUND OF THE INVENTION
Field Or the Invention
The present invention relates to a lubricant
supplying apparatus or oil air lubricating apparatus
for supplying lubricant to an object to be lubricated
such as a bearing for supporting a spindle or shaft
of a rolling machine or a machine tool and the like,
in a condition that the lubricant is moved along an
lnner sur~ace oP a pipe by utilizing compressed air
(referred to as "oil air" hereinafter). More
particularly, it relates to a lubricant supplying
apparatus in which an abnormal oil supplying condition
(i.e., a condition that the oil air is not being
supplied to the obJect to be lubricated) can be
detected.
Related Background Art
An example of a lubricant supplying apparatus
in which oil air obtained by appropriately mixing
lubricant and compressed air is supplied to an object
to be lubricated is disclosed in the Japanese Patent
Laid-Open Application No. 2-271197 assigned to the
Applicant to the present application.
Such conventional lubricant supplying
apparatus fundamentally comprises a main unit for
supplying the lubricant and the compressed air, a
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1 mixer ror mixing the lubricant and the compressed
air to obtain an oil air condition, and distributors
~or distributing the oil air to various passages.
Particularly, by providing detection means for
optically detecting a rlOw of the oil air at a
downstream side of the mixer, it could be monitored
whether the optimum amount of oil air is supplied
from the mixer or not.
In the above-mentioned conventional apparatus,
although it is possible to monitor whether the
optlmum amount Or oil air is being supplied ~rom the
mixer or not, it cannot be ~udged whether the oil
air is surely sent to various ob~ects to be lubricated
such as bearings by the detection means. That is
to say, for example, even if there is the abnormity
such as the breakage in the pipe line directly
connected to the bearing, so long as the compressed
air is supplied in a normal condition, the flow
amount Or the lubricant and the ~low amount of the
air are not changed, with the result that it cannot
be judged whether the oil air is surely sent to the
bearing.
In order to detect whether the lubricant is
surely supplied to all of the ob~ects to be lubricated,
it is desirable to arrange optical sensors in ~ront
of all of the objects. However, since such optical
sensor is expensive, when such sensors are applied
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1 to an apparatus having several hundreds of areas
to be lubricated (for example, a continuous casting
machine having a number of guide rolls and pinch
rolls), the cost is increased extremely. Particularly,
since one feature of the oil air lubricating apparatus
is to surely and continuously supply a small amount
of lubricant, it was feared that it was difficult
to correctly detect the flow of the oil. In order
to detect the flow of the oil more correctly, since
a hi8her accurate sensor is required, when such
sensors are arranged at several hundreds of areas
as mentioned above, the cost is increased
considerably.
SUMMARY OF THE INVENTION
The present invention intends to eliminate
the above-mentioned conventional drawback, and has
an ob~ect to provide a lubricant supplying apparatus
in which an abnormal oil supply condition that oil
air is not surely supplied from a mixer to objects
to be lubricated can easily be detected with an
inexpensive construction even ir the abnormity is
caused by the breakage in a pipe line at a down-
stream side of the mixer.
To achieve the above ob~ect, according to
the present invention, there is provided a lubricant :-
supplying apparatus for supplying lubricant to an :
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1 object to be lubricated while moving the lubricant
along in an inner surface Or a pipe line by
utilizing compressed air. To wherein an orifice is
formed in a lubricant discharge line ror discharging
the lubricant from the object to be lubricated
to a drain, and a pressure change detecting means
for detecting the change in pressure in at least
one Or a lubricant supply line for supplying the
lubricant to the ob~ect to be lubricated ~upstream
side Or the ob~ect to be lubricated) and the
lubrlcant discharge line (downstream side of the
ob~ect to be lubricated) at an upstream side Or the
orifice is provided.
In accordance with the present invention,
since the orifice is rormed in the lubricant
discharge line for discharging the lubricant from
the ob~ect to be lubricated, so long as the
lubricant is correctly supplied to the ob~ects to
be lubricated, the pressure in the lubricant ;~
discharge line and the lubricant supply line at the
upstream side Or the orifice is kept to a
predetermined level. However, ir the movement Or
the oil alr is stopped ln the lubricant supply line
or at the distrlbutor disposed at the upstream side
Or the lubricant supply line, since the pressure at
that position is dropped, the pressure at the
upstream side of the orifice will be decreased. ;~
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1 Explaining the change in pressure concretely,
first of all, in the case where the change in
pressure in the lubricant supply line can be
detected by the pressure change detecting means, :
if the breakage or the clogging is caused in the
pipe line at the upstream side o~ the pressure
change detecting means, such abnormity will be
detected as the reduction of pressure. On the
other hand, if the breakage or the clogging is
caused in the pipe line at the downstream side of
the pressure change detecting means, the breaka8e
will be detected as the reduction Or pressure and
the clogging will be detected as the increase of
pressure.
On the other hand, in the case where the
change in pressure in the lubricant discharge line
at the upstream side Or the orifice can be detected
by the pressure change detecting means, for example,
if the breaka8e o~ the sealing on the object to be
lubricated, and the breakaBe or clogging in the ~:~
lubricant supply line are caused, such abnormity i ~:~
will be detected as the reduction of the pressure.
According to the present invention, since
the ori~ice is ~ormed ln the lubricant discharge
line and the pressure change at the upstream side
of the orifice can be detected, it is possible to ::~
detect a condition that the oil air is not correctly
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1 being supplied to the object to be lubricated, with
an inexpensive construction. Further, even when a
small amount o~ lubricant is conveyed as the oil
air, the abnormity can easily be detected.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 is a constructural view showing a
first embodiment of the present invention; and
FiB. 2 is a constructural view showing a
second embodiment of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The present invention will now be explained
in connection with embodiments thereof with reference
to the accompanying drawings.
Flg. 1 is an explanatory view showing a
~irst embodiment of the present invention. First
of all, explaining the whole construction, a mixer
1 serves to mix compressed air and lubricating oil
supplied from a main unit (not shown), thereby
forming oil air, and equally sent the oil air to
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six distribution ports la to 1f. Incidentally,
since the concrete constructions of the mixer 1
and the main unit are already known (as disclosed ~
in the above Japanese Patent Laid-open Application ~ :
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No. 2-271197), the explanation thereof will be omitted.
In this embodiment, six distributors 2A to
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1 2F are provided for the single mixer 1, and the
distribution ports 1a to lf of the mixer 1 are
connected to oil supply ports 2a to 2f o~ the
distributors 2A to 2F via pipes 3a to 3f,
respectively.
Each of the distributors 2A to 2F has a
plurality Or (four, in this embodiment) distribution
ports 4 corresponding to the number of objects (to
be lubricated) to which the air oil is supplied.
Incidentally, since the construction at a
downstream side o~ each distribution port 4 is the
same as that of the other distribution ports 4,
such construction will be explained only with
reference to one distribution port 4 Or the
distributor 2A, and the constructions associated
with the other distribution ports 4 will be not
explained and illustrated.
The distribution port 4 is connected to a
lubricating oil supply plpe 5 as a lubricant supply
line, the other end of which is connected to a
lubricating oil supply port 7a of a bearing 7 as
the object to be lubricated. On the other hand,
a lubrlcatlng oll discharge port 7b of the bearing
7 ls connected to an oll tank 9 via a drain pipe
8 as a lubricant discharge line. An orifice 10
is formed in ~he drain ~ipe 8 at its intermediate
portion, and there is provided a pressure sensor
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1 (pressure change detecting means) 11 for measuring
the pressure in the pipe at a downstream side of
the ori~ice 10.
Next, an operation of the lubricant
supplying apparatus according to this embodiment
will be explained.
In a normal oil supply condition, due to
the restricting erfect o~ the orifice 10 formed
in the drain pipe 8, the pressure (air pressure)
in the drain pipe 8 at an upstream side of the
orl~ice 10, the bearlng 8 and the lubricating oil
supply pipe 5 is maintained to 0.2 to 0.4 kg/cm2.
So long as the pressure sensor 11 indicates such
pressure value, it can be ~udged that an optimum
amount of oil is supplied to the bearinB 7. The
reason is that, in the oil air lubricating apparatus,
since the lubricating oil is moved along in inner
surfaces Or the pipes by utilizing the compressed
air, the continuous supply of the compressed air
means that the lubricating oil is beinB moved (and
only the lubricating oil is not supplied if the
compressed air is not supplied).
Explaining more concretely, for example,
if the clogging is caused ln the pipe 3a, distrlbutor
2A and/or lubricating oil supply line 5 not to
correctly send the air oil to the bearin8 7, since
the pressure is increased at the clogged area, the
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1 pressure in the drain pipe 8 communicated with the
line 5 is decreased from the normal pressure value.
On the other hand, for example, if the oil air is
not supplied to the bearing 7 by opening or
releasing the pipe line at the upstream side Or the
oririce 10 due to the breakage Or the pipe 3 and/or
the lubricating ail supply line 5 or due to the
leakage Or oil because Or the deterioration Or the
sealing means between the distribution port 1a and
the pipe 3a or any abnormity in the other connecting
portion, the pressure in the drain pipe 8 will also
be decreased. Further, no matter what the oil air
may reach the bearinB 7, if the normal lubrication
is not efrected due to the damage Or the seal in
the bearing 7, the pressure in the drain pipe 8
will also be decreased from the normal pressure
value.
Accordingly, with the arranBement according
to the illustrated embodiment, if the abnormal oil
supply condition that the oil air is not correctly
supplied to the bearinB 7 occurs, since the pressure
in the drain pipe 8 is decreased and such reduction
Or pressure can be detected by the pressure sensor
11, such abnormlty can easlly be detected. Since
such abnormity can be detected by only two elements,
i.e., the orifice 10 and the pressure sensor ll, it
is very cheap. Thus, even when the illustrated
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1 embodiment of the present invention is applied to a
continuous casting machine having a number of guide
rolls and pinch rolls to generate a several hundreds
of areas to be lubricated, the total cost is not
so increased as much.
Further, according to the illustrated
embodiment, since the abnormal oil air supplying ~ ;
condition is detected by the change in the pressure
value in the pipe, even when a small amount of
lubricating oil is conveyed as the oil air, the
abnormity can easily be detected.
Incidentally, in the illustrated embodiment,
since the abnormity causes the reduction of pressure,
in place of the pressure sensor 11, a pressure
switch for detecting the fact that the pressure is
decreased below a predetermined value may be used.
In this case, since the pressure switch is generally
cheaper than the pressure sensor, the cost can be
further reduced.
Fig. 2 is an explanatory view showing a
second embodiment of the present invention.
Regarding the second embodiment, only the difference
from the first embodiment will be described.
In the second embodiment, a pressure sensor
11 is provided in connection with the lubricating
oil supply pipe 5 at the upstream side of the
bearing 7, in place of the drain pipe 8 at the
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1 downstream side of the bearing 7.
With this arrangement, ir the clogging or
the breakage is caused in the pipe 3a, distributor
2A and/or pipe 5 at the upstream side Or the
pressure sensor 11, since the pressure at the
downstream side Or the clogged portion or the
broken portlon is decreased, the abnormity can be
detected by the reduction Or the measured value in
the pressure sensor 11 . On the other hand, if the ~
clogging is caused in the pipe 5 or 8 at the ~ :
downstream side Or the pressure sensor 11, since
the pressure at the upstream side Or the clogged
portion is increased, the abnormity can be detected . -
by the increase in the measured value in the
pressure sensor 11. Further, if the open condition
due to the breakaBe is caused at the downstream ~;
side Or the pressure sensor 11, since the pressure
in the lubricating oil supply pipe 5 is decreased,
the abnormity can be detected by the reduction of
the measured value in the pressure sensor 11.
In this way, also with the arrangement
according to the second embodiment, the abnormal
oil supply condition that the oil air is not
correctly supplied to the bearin8 7 can be detected
by the change in the measured value in the pressure
sensor 11, as in the first embodiment. Further,
in the second embodiment, since the pressure in
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1 the pressure sensor 11 is increased or decreased
according to the kinds of abnormity, the kind of
the abnormity can be judged to some extent on the
basis of the change in the measured value in the
pressure sensor 11. -~:~
Incidentally, also in the second embodiment,
a pressure switch may be used in place of the ~:
pressure sensor 1 1 . However, in this second -; :
embodiment, slnce the pressure in the pressure
sensor 11 is increased or decreased according to
the kinds of abnormity, two pressure switches one : :~
of which can detect the increase in pressure and
the other of which can detect the reduction of
pressure or a single pressure switch having two
contacts must be used.
Incidentally, in the illustrated embodiment,
while examples that the pressure sensor 11 is
provided in connection with one of the lubricating
oil supply pipe 5 and the drain pipe 8 were . :
explained, in order to improve the detecting
accuracy, the pressure sensors 11 or the pressure ~ .
switches may be provided in connection with both
o~ the lubricating oil supply pipe 5 and the drain
pipe 8. Further, while the bearing 7 was illustrated
as the object to be lubricated, such object is not
limited to the bearing.
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