192 clutches and power-stop control – Clutches – Fluent material
Reexamination Certificate
1999-12-30
2001-06-19
Marmor, Charles A. (Department: 3688)
192 clutches and power-stop control
Clutches
Fluent material
C192S058681
Reexamination Certificate
active
06247567
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a fluid clutch provided with a function of automatically controlling the operation of a cooling fan applied mainly to an internal combustion engine of a vehicle in response to an ambient temperature condition.
2. Description of the Prior Arts
As a fluid clutch for controlling the rotation of a cooling fan of an internal combustion engine of a vehicle, a type of fluid clutch which transmits a driving torque of a driving disc to a case by oil supplied to a torque transmitting chamber has been typically used. As the structure of such a fluid clutch, for example, a constitution of a coupling device (fluid clutch) where the inside of a sealed case is divided into the torque transmitting chamber and an oil reserving chamber by means of a partition plate, the driving disc which is driven by a driving part is rotatably disposed in the inside of the torque transmitting chamber, oil in the oil reserving chamber is supplied to the torque transmitting chamber through a flow-out adjusting hole formed in the partition plate, and oil in the torque transmitting chamber is returned to the oil reserving chamber through a circulation passage has been known (see Japanese publication SHO 63-21048). In this type of fluid clutch, the driving torque of the driving disc is transmitted to the sealed case by oil supplied to the torque transmitting chamber from the oil reserving chamber, a fan mounted on the sealed case is rotated so that the cooling of an engine of a automobile is performed, for example. Furthermore, in this type of fluid clutch, an ambient temperature is detected by a bimetal and in response to the elevation of the detected temperature, the degree of opening of the flow-out adjusting hole is increased. Accordingly, an amount of oil in the inside of the torque transmitting chamber is increased so that the rotational speed of the sealed case is increased and the fan is rotated at a high speed thus enhancing the cooling effect.
This type of fluid clutch, however, has following problems.
That is, under the condition that a large amount of oil is present or filled in the inside of the torque transmitting chamber, at the time of restarting the engine or at the time of rapid acceleration during the operation, following the acceleration of the driving disc of the driving side, the rotation of the case of the driven side (cooling fan) is also rapidly increased due to a large amount of oil present in the inside of the torque transmitting chamber, although for a short time. This phenomenon is generally called ‘a drag phenomenon’ or ‘an attendingly rotating phenomenon’ and gives rises to a noise of fan and an accompanying discomfort and deteriorates the fuel expense.
‘The drag phenomenon’ of the conventional fluid clutch which occurs at the time of restarting the engine becomes more apparent corresponding to the increase of an amount of oil in the inside of the torque transmitting chamber. As means for solving this problem, for example, Japanese publication SHO 63-21048 proposes means where oil flowed out through the flow-out adjusting hole of the partition plate is first introduced to the opposite side in the diametral direction and then is supplied to the inside of the torque transmitting chamber.
With such a structure, under the condition that substantially no oil is present in the torque transmitting chamber and a large amount of oil is present in the oil reserving chamber, even when the engine is stopped, the inflow of oil from the oil reserving chamber to the torque transmitting chamber can be prevented and hence, no ‘drag phenomenon’ occurs at the time of restarting the engine. However, under the condition that a large amount of oil is present in the inside of the torque transmitting chamber, the structure is not effective for the prevention of ‘the drag phenomenon’ at the time of restarting after the engine is stopped and at the time of rapid acceleration during the operation.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide a fluid clutch which can prevent the occurrence of ‘the drag phenomenon’ in the above-mentioned various conditions, can reduce the noise of the fan and can enhance the reduction of the fuel expense.
The present invention is directed to a fluid clutch where in the inside of a torque transmitting chamber, a gap between a driving disc and an inner wall of the chamber can be varied, and the gap is controlled in response to various control signals from a computer mounted on a vehicle and hence, the rotational speed of a fan is controlled by changing an output torque. According to the first aspect of the present invention, in the fluid clutch including a driving part, a rotary shaft rotated by the driving part, a driving disc rotatably driven by the rotary shaft, a sealed case accommodating the driving disc and disposed rotatably on the rotary shaft, and a torque transmitting chamber formed in the sealed case and incorporating the driving disc therein, wherein a driving torque of the driving disc is transmitted to the sealed case by oil supplied to the inside of the torque transmitting chamber, the improvement is characterized in that in the inside of the torque transmitting chamber, a movable disc which faces the driving disc disposed in the inside of the torque transmitting chamber with a gap therebetween is resiliently supported in such a manner that the gap can be varied, an electromagnet which is disposed at a position outside of the movable disc side of the sealed case where the electromagnet faces the movable disc and attracts the movable disc is supported on the rotary shaft, whereby the gap between the driving disc and movable disc is varied by the electromagnet. According to the second aspect of the present invention, in the fluid clutch including a driving part, a rotary shaft rotated by the driving part, a driving disc rotatably driven by the rotary shaft, a sealed case accommodating the driving disc and disposed rotatably on the rotary shaft, a torque transmitting chamber for incorporating the driving disc therein and an oil reserving chamber for reserving oil which are formed in the sealed case thus constituting a mechanism where oil is supplied to the inside of the torque transmitting chamber from the oil reserving chamber so as to transmit a driving torque of the driving disc to the sealed case, a discharge passage which sends oil supplied to the torque transmitting chamber through a dam mechanism formed in an inner peripheral surface of the sealed case to the oil reserving chamber from the torque transmitting chamber, a partition plate which is provided with a flow-out adjusting hole for oil which makes the oil reserving chamber and the torque transmitting chamber communicate with each other, and a valve member disposed in the inside of the oil reserving chamber, wherein the flow-out adjusting hole is opened or closed in response to the deformation of the valve member caused by the change of temperature of a temperature sensitive body made of a bimetal which is disposed outside of the oil reserving chamber side of the sealed case, the improvement is characterized in that in the inside of the torque transmitting chamber, a movable disc which faces the driving disc disposed in the inside of the torque transmitting chamber with a gap therebetween is resiliently supported in such a manner that the gap can be varied, an electromagnet which is disposed at a position outside of the movable disc side of the sealed case where the electromagnet faces the movable disc and attracts the movable disc is supported on the rotary shaft, whereby the gap between the driving disc and the movable disc is varied by the electromagnet.
The first and second aspects of the present invention are also characterized in that a plurality of pins which protrude in an axial direction are mounted on the inner surface of the sealed case and the distal end portions of the pins are slidably fitted into holes formed in the movable disc.
In the present invention, by narrowing
Casella Anthony J.
Hespos Gerald E.
Marmor Charles A.
Porco Michael J.
Rodriguez Saul
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