Temperature-sensing fan fluid coupling

A temperature-sensing fan fluid coupling for use with an automobile engine. The coupling comprises a sealed enclosure, a partition plate having an outflow control hole, a thermostat mounted upon the front surface of the enclosure, a rodlike link member in contact with the thermostat at its one end, an interlocking member against which the link member bears, and a resilient tonguelike valve member. One end of the valve member is fixed, while the other end is in resilient contact with the front end of the interlocking member. The thermostat is connected to the valve member via the link member and the interlocking member. As the ambient temperature changes, the thermostat deforms to cause the valve member to more or less open the hole.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to improvements in the structure of a 
temperature-sensing fan fluid coupling which permits the engine fan of an 
automobile to be rotated to automatically supply more or less cooling air 
according to the operating conditions of the engine at all times. 
2. Description of the Prior Art 
A typical fan fluid coupling of this kind is shown in FIG. 4, where a round 
hole 14' is formed in a partition plate 14 to control the outflow of oil. 
A resilient valve member 15 is mounted in the coupling and takes the form 
of a flat sheet. When temperature varies, a temperature-sensing device 
(not shown), such as a thermostat, mounted outside deforms, and the valve 
member 15 interlocks with a rodlike link member (not shown) in response to 
the deformation. At this time, the flat front end portion of the valve 
member 15 moves forward or rearward to directly close or open the hole 
14'. The characteristic of the coupling is indicated by curve (B) of FIG. 
5. 
This prior art fan fluid coupling is unable to sufficiently control the 
outflow of oil, because the hole 14' is directly closed or opened by the 
flat front end portion of the valve member 15 which moves forward or 
rearward. As indicated by the characteristic curve (B), the frequency of 
the fan suddenly changes in a stepwise manner at a predetermined 
temperature, usually 60.degree. C. under normal operating conditions. 
Consequently, the amount of cooling air cannot be controlled adequately 
according to any great temperature change occurring while the vehicle is 
running. Hence, fan noise and power drain cannot be satisfactorily 
reduced. Also, the time taken to warm up the engine cannot be shortened 
sufficiently. 
SUMMARY OF THE INVENTION 
It is an object of the invention to provide a temperature-sensing fan fluid 
coupling which allows an appropriate amount of cooling air to be always 
supplied according to the operating conditions of an engine and in 
response to temperature changes in such a way that the amount of air is 
varied substantially continuously. 
The invention provides a temperature-sensing fan fluid coupling comprising: 
a sealed driven enclosure mounted to a rotating main shaft via a bearing, 
the shaft having a driving disk rigidly fixed thereto at the front end of 
the shaft, the enclosure having fan blades mounted upon the outer 
periphery of the enclosure; a partition plate which divides the inside of 
the enclosure into an oil reservoir chamber and a torque transmission 
chamber and which is provided with a hole for controlling the outflow of 
fluid, the disk being mounted inside the torque transmission chamber; a 
small reservoir formed in the inner side surface of the enclosure which is 
opposite to the outer side surface of the disk and upon which oil collects 
during rotation; a circulation passage extending from the torque 
transmission chamber to the oil reservoir chamber and communicating with 
the small reservoir; a temperature-sensing device mounted upon the front 
surface of the enclosure; a rodlike link member which is moved according 
to deformation of the temperature-sensing device that is caused by 
temperature changes; and a valve member which, when the ambient 
temperature exceeds a preset value, is caused to open the hole by the link 
member and which, when the temperature is lower than the preset value, is 
caused to close the hole by the link member, the valve member consisting 
of a resilient tonguelike member mounted inside the fluid coupling. The 
front end of the link member is resiliently connected to the front end of 
the resilient tonguelike valve member which is close to the hole and opens 
or closes it. One end of the valve member is rigidly fixed to the inner 
wall of the oil reservoir chamber. The effective contact area of oil 
inside a torque transmission space formed by the opposite surfaces of the 
disk and the enclosure is increased or decreased to control the torque 
transmitted from the driving main shaft to the driven enclosure. 
In one feature of the invention, said hole for controlling the outflow of 
fluid extends radially of the partition plate, and the valve member is 
curved upward. 
In this structure, the resilient tonguelike valve member that is close to 
the hole for controlling the outflow opens or closes the hole. The front 
end of the link member is either resiliently connected to the valve member 
via an interlocking member mounted in the oil reservoir chamber or in 
resilient contact with the valve member. As the ambient temperature 
changes, the link member moves forward or rearward, and the fulcrum moves 
continuously from the rigidly fixed point toward the outflow control hole. 
As a result, the opening of the hole is varied continuously. Consequently, 
the rotational frequency is in proportion to the temperature of the 
surroundings as indicated by characteristic curve (A) of FIG. 5, where the 
temperature (T) is plotted on the horizontal axis and the rotational 
frequency (F) of the fan on the vertical axis. 
Other objects and features of the invention will appear in the course of 
description thereof which follows.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Referring to FIGS. 1-3(C), a driving disk 2 is rigidly fixed to the front 
end of a rotating main shaft 1 which has a flanged wall 1' at its front 
end. A casing 3" is mounted on the shaft 1 via a bearing. The casing 3" 
has a front cover 3' which is sealed to form a sealed driven enclosure 3. 
The inside of the sealed enclosure 3 is partitioned into an oil reservoir 
chamber 5 and a torque transmission chamber 6 by a partition plate 4. This 
partition plate 4 is provided with a hole 4' to control the flow of oil 
from the oil reservoir chamber 5 to the torque transmission chamber 6. A 
torque transmission space 6' is formed between the opposite surfaces of 
the disk 2 and the sealed enclosure 3 inside the torque transmission 
chamber 6. 
A temperature-sensing device 10 consists of a bimetallic strip, for 
example, both ends of which are anchored to a fixture 7 fixed to the front 
surface of the cover 3'. One end of an interlocking member 8 is riveted to 
the surface of the partition plate 4 on the side of the oil reservoir 
chamber 5, while the other end is located close to the hole 4'. As the 
ambient temperature changes, the temperature-sensing device 10 deforms, 
thus deforming the interlocking member 8 via a rodlike link member 11. The 
interlocking member 8 is disposed inside the oil reservoir chamber 5. A 
small reservoir 9' is formed in the inner wall surface of the casing 3" 
which is opposite to the outer surface of the disk 2 and upon which oil 
collects. A passage 9 through which oil circulates extends from the torque 
transmission chamber 6 to the oil reservoir chamber 5. The transmission 
chamber 6 is close to the small reservoir 9' which is on the upstream side 
of the passage 9 in the direction of rotation. A resilient tonguelike 
valve member 12 is located close to the hole 4' that controls the outflow. 
One end of the valve member 12 is rigidly fixed by a rivet, bolt or screw 
12' either to the partition plate 4 or to the cover 3' as shown in FIG. 
3(B), while the other end lies over the hole 4' to open or close it. The 
front end of the valve member 12 is in resilient contact with the front 
end of the interlocking member 8. 
As shown in FIG. 3(C), the link member 11 can be in direct contact with the 
tonguelike valve member 12 that is made long. Also, the hole 4' which 
controls the outflow can be made long radially of the partition plate 4. 
Preferably, the valve member 12 is curved upward. 
As described thus far, the novel temperature-sensing fan fluid coupling 
opens or closes the outflow control hole 4' by the tonguelike valve member 
12 always in response to great changes in the ambient temperature which 
occur while the vehicle is running. Thus, the amount of oil flowing toward 
the torque transmission chamber 6 can be controlled effectively. 
Therefore, the amount of cooling air is controlled substantially 
continuously and appropriately according to the operating conditions of 
the engine over a wide range. Further, the internal structure is simple, 
since it consists essentially of the tonguelike valve member 12 alone. In 
this way, the novel temperature-sensing fan fluid coupling is quite 
useful. 
The amount of cooling air can be controlled more certainly by making the 
outflow control hole 4' long as mentioned above and, at the same time, 
curving the valve member 12 upward, in addition to the provision of the 
above-described structure. Furthermore, the amount of outflow of oil can 
be controlled continuously as may be desired by appropriately curving the 
valve member.