Internal-combustion engines – Cooling – Automatic coolant flow control
Reexamination Certificate
2002-07-02
2004-11-09
Tyler, Cheryl J. (Department: 3746)
Internal-combustion engines
Cooling
Automatic coolant flow control
C417S228000, C192S111400, C192S058610
Reexamination Certificate
active
06814033
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a temperature sensitive fluid type fan coupling apparatus adapted to constantly supply cooling air to an engine at such a cooling air supply rate that is in accordance with the traveling condition by controlling the rotation of an engine cooling fan generally in an automobile.
2. Description of the Related Art
This kind of related art fan coupling apparatus is generally of a system in which the driving torque of a driving disk is transferred to a case by an oil supplied to a torque transfer chamber. The known structures of this kind of fan coupling apparatus include, for example, a structure of the temperature sensitive fluid type fan coupling apparatus (refer to Japanese Patent Publication No. 21048/1988) in which the interior of a sealed case is divided by a partition into a torque transfer chamber and an oil reservoir chamber, a driving disk being provided in the torque transfer chamber so that the driving disk can be rotated by a driving force of a driving unit, the oil in the oil reservoir chamber being supplied to the torque transfer chamber from an outflow regulating port formed in the partition or a cover, the oil in the torque transfer chamber being returned to the oil reservoir chamber from an oil circulating passage. According to this kind of fan coupling apparatus, the driving torque of the driving disk is transferred to the case by the oil supplied from the oil reservoir chamber to the torque transfer chamber, and a fan fixed to the case is rotated, the cooling of, for example, an engine of an automobile being thereby done. This kind of fan coupling apparatus is adapted to detect the atmospheric temperature by a strip of fancy paper-like or spiral bimetal, and increase the degree of opening of the outflow regulating port when this temperature increases. Thus, the quantity of the oil in the torque transfer chamber is increased, and a rotational frequency of the case is heightened to thereby rotate the fan at a high speed and improve the cooling effect.
However, this kind of fan coupling apparatus has problems which will be described below.
Namely, when the engine is restarted with a large quantity of oil existing in the torque transfer chamber, or when the engine is accelerated suddenly while the vehicle travels, an increase in a rotational frequency of the case (cooling fan) on the driven side also occurs, though for a short period of time, following up the acceleration of the driving disk on the driving side due to the oil existing in large quantities in the torque transfer chamber. This phenomenon is generally called a “drag” phenomenon, and causes the noise of a fan and an unpleasant feeling attended therewith. Also, an engine output is absorbed, and fuel consumption is deteriorated.
The fan coupling apparatuses which eliminate such a “drag ” include, for example, a fan coupling apparatus (Japanese Patent Publication No. 21048/1988) in which an oil flowing out from a supply port made in a partition is once guided to a diametrically opposite side and then supplied to the interior of a torque transfer chamber, a fan coupling apparatus in which a driving disk is formed to a hollow structure with an auxiliary oil reservoir chamber (idle oil reservoir chamber) provided therein, or a fan coupling apparatus of a system in which a large quantity of air-generating fan is operated at a low rotational speed, and a similar fan coupling apparatus.
However, a related art temperature sensitive fluid type fan coupling apparatus had drawbacks which will be described below.
FIG. 3
illustrates a general related art fan coupling apparatus, which is formed by dividing the interior of a sealed case
111
by a partition
114
into a torque transfer chamber
112
and an oil reservoir chamber
113
, and mounting in the torque transfer chamber
112
a driving disk
115
of a solid structure rotatably on a rotary shaft body
116
, which is rotated by a driving force of a driving unit (not shown); via a bearing
117
so that a torque transfer clearance
112
-
1
is formed between the driving disk
115
and an inner circumferential surface of the torque transfer chamber
112
, an oil in the oil reservoir chamber
113
being supplied from an outflow regulating port
114
-
1
provided in the partition
114
into the torque transfer chamber
112
by a valve member
118
operated in accordance with variation of an external ambient temperature, the oil in the torque transfer chamber
112
being returned to the oil reservoir chamber
113
through a circulating passage
121
. A reference numeral
119
denotes a dam provided on the portion of an inner circumferential surface of the sealed case
111
which is opposed to an outer circumferential surface of the driving disk
115
on which outer circumferential surface the oil is collected during the rotation of the same disk, and
120
a temperature sensitive member (bimetal) provided on the outer side of the sealed case
111
.
However, in the fan coupling apparatus of such a structure, the oil flowing out of the outflow regulating port
114
-
1
of the partition
114
resides in a space
112
-
2
on the front side of the torque transfer clearance
112
-
1
, and continues to reside (stagnate) in this space until the quantity of oil attains a level high enough to obtain a pressure (water head of the oil) which permits the oil to flow into the torque transfer clearance
112
-
1
, and which occurs owing to a centrifugal force, or until the temperature of the oil increases to cause the viscosity thereof to lower. This residing oil continued to flow into the torque transfer clearance
112
-
1
even when the oil existing on the side of an outer circumference of the torque transfer clearance
112
-
1
started being discharged toward the oil reservoir chamber
113
by the dam
119
at the time of acceleration and starting of an engine, and effected the transfer of the torque. This caused the “drag” phenomenon mentioned above, and a delay of operation. Since this residing oil existed, a large total quantity of oil was needed.
FIG.
4
and
FIG. 5
illustrate fan coupling apparatuses provided with an auxiliary oil reservoir chamber (idle oil reservoir chamber) by forming a driving disk to a hollow structure. Out of these fan coupling apparatuses, the fan coupling apparatus shown in
FIG. 4
is formed in the same manner as the fan coupling apparatus shown in
FIG. 3
, except that a driving disk is made hollow. The fan coupling apparatus of
FIG. 4
is formed by dividing the interior of a sealed case
111
into a torque transfer chamber
112
and an oil reservoir chamber
113
by a partition
114
, and mounting rotatably in the torque transfer chamber
112
a driving disk
145
, which has an idle oil reservoir chamber
145
-
1
formed by making an inner portion of the disk
145
hollow, communication port
145
-
2
, which communicates with the torque transfer chamber
112
, in a side wall of the same disk and a centrifugal valve
145
-
3
adapted to open and close the communication port, on a rotary shaft body
116
, which is rotated by a driving force of a driving unit (not shown), via a bearing
117
so that a torque transfer clearance
112
-
1
is formed between the driving disk
145
and an inner circumferential surface of the torque transfer chamber
112
, the oil in the oil reservoir chamber
113
being supplied from the outflow port
114
-
1
provided in the partition
114
into the torque transfer chamber by the valve member
118
which is operated in accordance with variation of an external ambient temperature, the oil in the torque transfer chamber
112
being thereby returned to the oil reservoir chamber
113
through a circulating passage (not shown), a guide member
114
-
2
for introducing the oil in the oil reservoir chamber
113
directly into the idle oil reservoir chamber
145
-
1
being provided on the partition (refer to Japanese Patent Publication No. 28778/1984). Namely, this fan coupling apparatus has a system in which the oil flowing out from the outflow reg
Ito Haruyasu
Kubota Satoshi
Yamada Masato
Casella Anthony J.
Hespos Gerald E.
Tyler Cheryl J.
Usui Kokusai Sangyo Kaisha Limited
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