GB2247512A

GB2247512A - Fluid friction clutch

Info

Publication number: GB2247512A
Application number: GB9118638A
Authority: GB
Inventors: Yuichi Ono; Mitsuaki Hatori; Hiroshi Inoue
Original assignee: Usui Kokusai Sangyo Kaisha Ltd
Current assignee: Usui Kokusai Sangyo Kaisha Ltd
Priority date: 1990-08-30
Filing date: 1991-08-30
Publication date: 1992-03-04
Anticipated expiration: 2011-08-30
Also published as: KR940007892B1; FR2666390A1; KR920004745A; GB9118638D0; FR2666390B1; GB2247512B; DE4128791C2; DE4128791A1

Abstract

A fluid friction clutch comprises a driving section 1, a rotational shaft 2 rotated by the driving section 1, a driving 10 disc 5 rotationally driven by the rotational shaft, a casing 4 in which the driving disc is incorporated and which is rotatable about the rotational shaft, a fan 15 attached to the casing, and an oil-filled torque transmission gap defined between the driving disc 5 and the casing 4 for transmitting the driving 4 torque of the driving disc to the casing, wherein an oil supply 6 means is arranged for supplying oil from the outside to the inside of the casing and the oil supply means is connected by way of an oil supply pipe 16 to either side of the casing. The supply means is operated by a control unit receiving 6 information concerning the speeds of the shaft and the fan, and the temperature of cooling water. The casing may include a breather (30, Fig. 6). <IMAGE>

Description

1 01 7.7 FLUID CLUTCH The present invention concerns a f luid clutch and,

more in particular, it relates to a fluid clutch adapted to transmit a driving torque of a driving disc to a casing fitted with a fan by means of an oil filled torque transmission gap of the casing.

A coupling device having a structure such that the inside of a casing is divided by a partition plate into a torque transmission chamber and an oil reservoir chamber, a driving disc is disposed in the transmission chamber so as to be rotatable under driving f rom a driving section, oil in the oil reservoir chamber is supplied through a f low control hole formed in the partition plate to the transmission chamber and the oil in the transmission chamber is returned by way of a circulation path to the oil reservoir chamber has been disclosed, for example, in Japanese Patent Application Sho 6321048. In a coupling device of this type, the driving torque of the driving disc is transmitted to the casing by means of oil supplied from the oil reservoir chamber to the transmission chamber, to rotate the fan attached to the casing, for example, for cooling an automobile engine.

In the known coupling device described above, ambient temperature is detected by a bimetallic element and, if the temperature is elevated, the opening of the flow control hole is increased to increase the amount of oil in the transmission 2 chamber, and this increases the rotation of the casing thereby rotating the fan at a higher speed to improve the cooling effect. However, an automobile engine is driven under various conditions. For instance, while the driving disc is rotated at a high speed, during running on a highway, there is no requirement to rotate the fan at such a high speed since the cooling effect is increased by the air stream caused by movement of the automobile. Further, upon cold starting, it may be intended to rotate the fan at a low velocity since high speed rotation of the fan will inhibit operation under warm condition and also cause fan noises. Thus, an optimum control is required depending on the respective cases. For satisfying such demands, it is insufficient to control the amount of an oil according only to the atmospheric temperature.

Further, since the control is conducted by the oil sealed in the casing in the known system, the oil tends to be degraded and it is impossible to control the amount of oil with accuracy imposing a limit on the control which can be achieved.

Furthermore, in the known system, since the driving source rotates the driving disc, vibrations or impact shocks from the driving source are directly transmitted to bearings attached to a rotational shaft of the driving disc, causing problems due to wear.

The present invention has been accomplished in view of the foregoing disadvantages of the fluid clutch of this type and 3 an object of the present invention is to provide a fluid clutch having an optimum control by adjusting the amount of an oil at a hiqh accuracy depending on various kinds of operation conditions.

Another object of the present invention is to provide a fluid clutch of excellent durability.

The foregoing object can be attained in accordance with the first aspect of the present invention by a fluid clutch comprising a driving section, a rotational shaft rotated by the driving section, a driving disc rotationally driven from the rotational shaft, a casing in which the driving disc is incorporated and which is rotatably disposed around the rotational shaf t as a centre of rotation, a f an attached to the casing, and an oil in a torque transmission gap defined between the driving disc and the casing for transmitting the driving torque of the driving disc to the casing, wherein an oil supply means is arranged to supply oil from the outside to the inside of the casing and the oil supply means is connected by way of an oil supply pipe with the casing.

The foregoing object can be attained also in accordance with the second aspect of the present invention by a fluid clutch comprising a driving section, a rotational shaf t rotated by the driving section, a cooling device for cooling the driving section, a driving disc rotationally driven from the rotational shaft, a casing in which the driving disc is incorporated and 4 which is rotatably disposed around the rotational shaft as a centre of rotation, a fan attached to the casing, and an oil filled in a torque transmission gap defined between the driving disc and the casing for transmitting the driving torque of the driving disc to the casing, wherein the fluid clutch comprises an oil supply means for supplying the oil from the outside to the inside of the casing, and a control means for controlling the supply of the oil by the oil supply means according to the rotation of the fan, the rotation of the rotational shaft and the temperature of cooling water of the cooling device.

The foregoing object can be attained in accordance with the third aspect of the present invention by a fluid clutch comprising a driving section, a rotational shaft rotated by the driving section, a cooling device for cooling the driving section, a driving disc rotationally driven from the rotational shaft, a casing in which the driving disc is incorporated and which is rotatably disposed around the rotational shaft as a centre of rotation, a fan attached to the casing, and oil in a torque transmission gap defined between the driving disc and the casing for transmitting the driving torque of the driving disc to the casing, wherein the fluid clutch comprises an oil supply means f or supplying the oil by way of the oil supply pipe f rom the outside to the inside of the casing, a data calculation means for calculating control data using at least the rotation of the fan, the rotation of the rotational shaft and the temperature of the cooling water of the cooling device as control signals and calculating the control data regarding f the control for the oil supply means according to the control signal and a control device for driving the oil supply means based on the control data obtained from the data calculation means.

The foregoing object can be attained in accordance with the fourth aspect of the present invention by a fluid clutch comprising a casing and disc incorporated therein, a driving section connected by a flexible joint to either the casing or the disc, bearings for rotatably supporting the other of the casing or the disc to a stationary portion and an oil supply means for supplying an oil from the outside to a torque transmission gap defined between the opposing surfaces of the casing and the disc.

The foregoing object can be attained in accordance with the fifth aspect of the present invention by a fluid clutch comprising a casing and a disc incorporated therein. a driving section connected by a flexible joint to either the casing or the disc, bearings for rotatably supporting the other of the casing or the disc to a stationary portion and an oil supply means for supplying oil from the outside to a torque transmission gap defined between,the opposing surfaces of the casing and, the disc, and a control means for controlling the supply of the oil by the oil supply means according to the rotation of the fan, the rotation of the casing and the temperature of cooling water to the driving section.

6 In the first aspect of the present invention, the rotational shaf t is rotationally driven by the driving section and the disc is rotationally driven by the rotation of the rotational disc. Oil is supplied from the outside by way of the oil supply pipe into the torque transmission gap defined between the driving disc and the casing that houses the driving disc.

The driving toque of the driving disc is transmitted by means of the oil, and the casing is rotated by the rotation of the driving disc and the fan attached to the casing is rotated.

In the second aspect of the present invention, the oil for transmitting the driving toque of the driving disc to the casing is supplied by the oil supply means from the outside to the torque transmission gap defined between the driving disc and the casing. Then the supply of the oil is controlled at by the control means according to rotation of the fan, the rotation of the rotational shaft rotationally driven by the driving section and the temperature of the cooling water of the cooling device. In this way, the amount of the oil is controlled properly at a high accuracy and the fan is rotated corresponding to various kinds of operation conditions.

In the third aspect of the present invention, the oil is supplied by the oil supply means from the outside to the torque transmission gap defined between the driving disc and the casing for transmitting the driving torque of the driving disc to the casing. In this case, the control data is calculated f X 7 by the data calculation means according to rotation of the f an, rotation of the rotational shaf t and the temperature of the cooling water of the cooling device. Then, since the oil is supplied by the oil supply based on the control data obtained f rom the data calculation means, the amount of the oil is controlled properly at a high accuracy and the fan is rotated corresponding to various kinds of operation conditions.

In the fourth aspect of the present invention, the disc or the casing is rotationally driven by the driving section by way of the flexible joint that does not transmit vibrations from the driving section to the casing or the disc, and the casing or the fan attached to the disc contained in the casing is rotated by the oil supplied by the oil supply means from the outside to the torque transmission gap formed between the opposed surfaces of the casing and the disc.

In the fifth aspect of the present invention, the disc or the casing is rotationally driven by the driving section by way of a flexible joint that does not transmit vibrations from the driving section to the casing or the disc. The casing or the fan attached to the disc contained in the casing is rotated by oil supplied by the oil supply means from the outside to the torque transmission gap formed between the opposed surfaces of the casing and the disc, by the control means according to rotation of the f an attached to the casing or the disc, the rotation of the casing and the temperature of the cooling water supplied to the driving section.

8 1 A fluid clutch in accordance with the present invention will now be described by way of example only, with reference to the accompanying drawings Figs. 1-21 in which:

Fig. 1 is a partial cross-section of a fluid clutch according to the present invention; Fig. 2 is a partial cross-section through another fluid clutch according to the present invention; Fig. 3 is a flow chart illustrating the operation of the fluid clutch of Fig. 1; Fig. 4 illustrates the characteristics of rotation and the temperature of the fluid clutch of Fig. 1; Fig. 5 illustrates other characteristics of the fluid clutch of Fig. 1;.

Fig. 6 is a partial cross-section of a fluid clutch according to a second embodiment of the present invention; Fig. 7 is a partial cross-section of an alternative fluid clutch according to a second embodiment of the present invention; Fig. 8 is a partial cross-section through a fluid clutch 9 according to a third embodiment of the present invention; Fig. 9 is a partial cross-section through a modified version of the fluid clutch of Fig. 8; Fig. 10 is a cross-section through a first modified embodiment of a pumping mechanism for use in a fluid clutch of the present invention; Fig. 11 is a cross-section through another pumping mechanism for use in a fluid clutch of the present invention; Fig. 12 is a cross-section through another pumping mechanism for use in a fluid clutch of the present invention; Fig. 13 is a cross-section through another mechanism for use in a fluid clutch of the present invention; Fig. 14 is a cross-section through another pumping mechanism for use in a fluid clutch of the present invention; Fig. 15 is a cross-section and side view of a pumping mechanism for use in a fluid clutch of the present invention; Fig. 16 is a cross-section and side view of a pumping mechanism for use in a fluid clutch of the present invention; Fig. 17 is a cross-section and side view of a pumping mechanism for use in a fluid clutch of the present invention; Fig. 18 is a cross-section and side view of a pumping mechanism for use in a fluid clutch of the present invention; Fig. 19 is a block diagram illustrating operation of a fluid clutch in accordance with a fourth embodiment of the present invention; Fig. 20 is a partial cross-section of a fluid clutch in accordance with a fifth embodiment of the present invention; Fig. 21 is a partial cross-section of a fluid clutch in accordance with a fifth embodiment of the present invention.

Referring at first to a first embodiment, Fig. 1 shows a fluid clutch, in which a rotational shaft 2 rotationally driven by engine 1 as a driving section has a cylindrical casting 4 mounted rotatably by way of bearings 3 around the axial centre of the rotational shaft 2 as the centre of rotation. A driving disc 5 is secured to one end of the rotational shaf t 2 inserted in the casing 4.

The inside of the casing 4 is divided by a partial wall 6 into a torque transmission chamber 7 and an oil supply section 8, in which the torque transmission chamber 7 and the oil supply section 8 are in communication with each other by way of a communication channel 10. The driving disc 5 is situated i 11 inside of the torque transmission chamber 7 to define a torque transmission gap between the outer circumferential surface and sides of the driving disc and the inner circumferential surface and sides of the torque transmission chamber 7 opposite thereto. An output pipe 12 is attached to the oil supply section 8 at the front surface of the casing 4 and the casing 4 is rotatably mounted by way of bearings 13 to the output pipe 12. In this way, the casing 4 is rotatably mounted by bearings 3 and 13 around each of the axial centres for the rotational shaft 2 and the output pipe 12 as the centre of rotation, and a fan 15 is secured to the casing 4.

An oil supply pipe 16 is secured at one end of the output pipe 12 and connected at its other end by way of a pump 17 to an oil reservoir 18, in which a silicone oil is stored. The pump 17 is driven by a motor 20 and supplies the silicone oil from the oil reservoir 18 by way of the oil supply pipe 16 into the casing 4 or returning the silicone oil from the inside of the casing 4 by way of the oil supply pipe 16 to the oil reservoir 18. The rotation of the motor 20 is controlled by a control signal from a control device 21, and the control device 21 receives detection signals from a fan rotation sensor 22 that counts the rotation of the fan 15, a rotational shaft of rotation detection sensor 23 for counting the rotation of the rotational shaft 2, and a cooling water sensor 24 for detecting the temperature of cooling water to the engine 1.

The present invention is not restricted to the above-mentioned 12 embodiment but the oil supply pipe 16 may be connected on the side of the rotational shaft 2 as shown in Fig. 2.

That is, a swivel joint 25 is disposed to the rotational shaft 2, and the oil supply pipe 16 is connected with the swivel joint 25.

A plurality of oil channels 2a, 2a,... are formed radially in the rotational shaft 2, and an oil channel 2b in communication with the radial channels is formed in the axial centre. Further, at least one through hole Sa is formed in communication with the oil channel 2b, radially penetrating the driving disc 5 and opened to the outer circumferential surface thereof. Other components are the same as those in Fig. 1. A plug 26 is arranged for closing the end of the oil channel 2b.

Description will now be made to the operation of the embodiment having the. arrangement shown in Fig. 1 and Fig. 2 with reference to the drawings.

Fig. 3 is a flow chart for the operation of this embodiment of Fig. 4 is a characteristic diagram for the operation of the embodiment and Fig. 5 is a characteristic diagram illustrating the relationship between rotation of the input shaft and rotation of the fan in this embodiment.

In this embodiment, detection data from the cooling water 13 sensor 24, the rotation sensor 23 and the fan rotation sensor 22 are inputted into the control device 21 at every predetermined interval of time, and read into a memory of the control device 21. At step S1 in Fig. 3, comparison is made between the water temperature data at present inputted f rom the cooling water sensor 24 and the water temperature data at a previous predetermined time to judge whether or not the difference between the data exceeds a predetermined reference value. In this decision, an allowable upper limit value and an allowable lower limit value f or the cooling water to the engine 1 are referred to for the decision.

If the result of the decision at the step S1 is YES, the process proceeds to a step S2, in which comparison is made between the rotational number data at present inputted from the rotation sensor 23 and the rotation data at a predetermined time before and it is determined whether or not the situation is in a rapid acceleration state. If the decision at step S2 is NO, the process proceeds to a step S3, in which comparison is made between the fan rotation data at present inputted from the fan rotation sensor 22 and the rotation data at a predetermined time before and it is determined whether or not the difference between both of the data exceeds a predetermined reference value.

if the decision at step 3 is NO, the process proceeds to a step S4, in which the pump 17 is driven by the motor 20 that operates by the control signal from the control device 21, and 14 the silicone oil in the oil reservoir 18 is supplied by way of the oil supply pipe 16 to the inside of the casing. Further, if the judgement at the step S3 is YES, the process proceeds to step S5, in which the pump 17 is driven by the motor 20 operated by the control signal from the control device 21 to return the silicone oil in the casing 4 by way of the oil supply pipe 16 to the inside of the oil reservoir.

The amount of the silicone oil supplied from the oil reservoir 18 to the inside of the casing or the amount of the silicone oil returned from the inside of the casing 4 to the oil reservoir 18 is set based on the detection data from the cooling water sensor 24, the rotation sensor 23 and the fan rotation sensor 22.

If the decision at step S1 is NO or the decision at step S2 is YES, the process proceeds to step S8 in which a decision is made whether or not the silicone oil is returned from the case 4 to the oil reservoir 18. Then, if the decision at step S8 is YES, the process proceeds to step S7 to maintain the state as it is. If the decision at step S8 is NO, the process proceeds to step S6, in which the pump 17 is driven being switched such that the silicone oil is returned from the casing 4 to the oil reservoir 18 by the control signal from the control device 21.

The operation period of returning the silicone oil at step S7, or the amount of the silicone oil supplied to the casing 4 at step S6 is determined according to detection data from the cooling water sensor 24, rotation sensor 23 and the fan rotation sensor 22.

In this embodiment, as shown in Fig. 4, if the temperature elevation rate of the cooling water is large near the upper limit value for the temperature of the cooling water to the engine 1, the rotation of the fan is increased. On the other hand, if when the temperature of the cooling water is lowered, the rotation of the fan is decreased. Further, if the rotation of the rotational shaft 2 is abruptly increased, the fan is controlled so as to decrease the rotation as shown by the dotted line to provide a reducing effect for the rotation of the fan as shown by the hatched line.

Further, in the rotation characteristics of the rotational shaft 2 and the blower 15 shown in Fig. 5, if the temperature of the cooling water to the engine 1 is a usual state, control is conducted in the region B, whereas the control is conducted in the region A if the temperature of the cooling water exceeds the upper limit value.

With such control, the amount of the silicone oil in the casing 4 is changed at a high accuracy and over a wide range by supplying the silicone oil from the oil reservoir 18 to the inside of the casing 4, or returning the silicone oil from the inside of the casing 4 to the oil reservoir 18.

16 Accordingly, an appropriate amount of the silicone oil corresponding to the temperature of the cooling water to the engine 1, the rotation of the rotational shaft 2 (in proportion with the rotation of the engine 1) and the rotation of the fan 15 is supplied from the communication channel 10 or the through hole 5a to the inside of the torque transmission chamber 7, or the silicone oil is withdrawn from the transmission chamber 7 through the communication channel 10 or the through hole 5a such that the amount of the silicone oil in the transmission chamber 7 is sufficient. Then, the torque of the driving disc 5 is transmitted by way of the appropriate amount of the silicone oil in the transmission chamber 7 to the casing to rotate the fan 15.

In this way, the rotation of the fan 15 is controlled such that it does not change greatly as shown in Fig. 4 by causing the silicone oil to be present in the transmission chamber 7 by such an amount as optimum to the temperature of the cooling water to the engine 1, the rotation of the engine 1 and the rotation of the fan 15. The temperature of the cooling water to the engine 1 is also kept substantially constant, the control is conducted under optimum conditions adaptable also to the cold starting and running on a highway, the noise of the fan 15 is lowered and wasteful fuel consumption can be prevented.

Although this embodiment has been described in which the amount of the oil in the casing is controlled based on the temperature 17 of the cooling water to the engine, the rotation of the engine and the rotation of the f an, the present invention is not restricted only to such an embodiment. For instance, other control factors may also include other factors such as amount of f low caused by movement of the automobile, atmospheric temperaturer intake air temperature, vehicle speed, throttle opening degree, atmospheric pressure, absence or presence of knocking, condition of the air conditioning, state of the exhaust brake, etc.

Description will now be made of a second embodiment according to the present invention with reference to Figs. 6 and 7.

The second embodiment is substantially identical to the first embodiment previously described with reference to Fig. 1 and it further includes an additional arrangement described below.

A breather 30 is arranged through the casing 4 in the torque transmission chamber 7. The breather 30 is adapted such that when the pressure in the torque transmission chamber 7 increases in excess of a predetermined upper limit value, only the gas in the torque transmission chamber 7 is released through the breather 30 out of the casing 4, and such that when the pressure in the torque transmission chamber 7 is lowered to less than the predetermined lower limit value, atmospheric air flows through the breather 30 into the torque transmission chamber 7.

18 A breather 30 is preferably arranged, as in the illustrated embodiment, both on the front and the rear sides of the casing 4, but it may be sufficient to arrange the breather at least on the side opposite to the side disposed with the oil supply pipe 16. If an air vent hole 31 is arranged passing through the driving disc 5 near the axial centre thereof, the silicone oil can enter and exit more smoothly by way of the oil supply pipe 16.

The present invention is not restricted to the foregoing embodiment but the oil supply pipe 16 may be connected on the side of the rotational shaft 2, (corresponding to the constitution of Fig. 2).

Other components of the second embodiment are identical with those in the first embodiment previously described.

In the second embodiment, when the pressure in the torque transmission chamber 7 increases beyond the predetermined upper limit value, gas in the torque transmission chamber 7 is released through the breather 30 to the outside of the casing 4 and, accordingly, the oil can enter and exit smoothly.

Further, if the pressure in the torque transmission chamber 7 is lowered to less than the predetermined lower limit value, since the external air flows in through the breather 30 into the torque transmission chamber 7, a negative pressure is not formed in the torque transmission chamber 7 and oil can be 19 delivered smoothly.

Other operations and ef f ects of the second embodiment are identical with those of the first embodiment described previously.

Description will now be made of a third embodiment according to the present invention with reference to Fig. 8 through Fig. 18.

In the third embodiment, as shown in Fig. 8, a dam 25 acting as a pumping mechanism is arranged on the inner circumferential wall of the casing 4 adjacent an oil supply port 7a in communication via a communication channel 10 with a torque transmission chamber 7, and the dam 25 pumps the oil from the side of the torque transmission chamber 7 to the side of an oil supply channel 8. A output pipe 12 is attached to the central portion of the oil supply channel 8 and a casing 4 is rotatably mounted by way of bearings 13 to the take-out pipe 12. In this way, the casing 4 is rotatably mounted by way of bearings 3, 13 to each of the axial centres of a rotational shaf t 2 and the output pipe 12 as the centre of the rotation, and a fan 15 to be driven is secured to the casing 4.

An oil supply port 7b is arranged on the inner circumferential wall of the casing 4 at a position preferably substantially opposite to the oil supply port 7a, and an oil supply channel 4a is formed between the oil supply port 7b and the output pipe 1 - 12 of the casing 4.

Other components of the third embodiment are identical with those of the first embodiment previously described.

Further, the present invention is not restricted to the abovementioned embodiment but the oil supply pipe 16 may be connected on the side of a rotational shaft 2 as shown in Fig. 9 (corresponding to Fig. 2).

In this case, a recess 51 is disposed to the outer circumferential wall of a driving disc 5 on the rear side of a through hole 5a in the rotational direction and a dam 25 is loosely attached to the recess 51. Other constitutions are the same as those shown in Fig. 8. A plug 28 is arranged for closing the end of an oil channel 2b.

In the present invention, the embodiment shown in Fig. 8 and the embodiment shown in Fig. 9 may be combined. That is, the f luid may be arranged such that the oil supply pipe 16 is connected to the side of the casing and the side of the rotational shaft 2 and the oil is supplied to or delivered from the torque transmission chamber by the pump 17, or the oil is supplied from the side of the rotational shaft 2 and delivered f rom the side of the casing 4, on the contrary, the oil is supplied on the side of the casing 4 and delivered from the side of the rotational shaft 2.

1 21 In this operation of the third embodiment, the pump 17 is driven by the motor 20 that is actuated by control signals from the control device 22 at the step SS in the flow chart of Fig. 3, and the silicone oil in the casing 4 is pumped by the dam 25 and returned by way of the oil supply channel 8 and the oil supply pipe 16 to the oil reservoir 18.

In this case, the suction performance of the pump 17 is increased by the pumping effect of the dam 25 located between the oil support port 7a and the support port 7a and the driving disc 5, and the silicone oil in the casing 4 is returned smoothly and rapidly into the oil reservoir 18.

In the third embodiment, with respect to the rotational characteristics of the rotational shaft 2 and the fan 15 shown in Fig. 5, the temperature ofthe cooling water to the engine 1 is controlled in region B - the usual state of temperature - but, if the temperature of the cooling water exceeds the upper limit value, the control is conducted in region A, in the same manner as in the first embodiment.

In this caser since the dam 25, which has the pumping function, is disposed between the oil supply port 7a and the driving disc 5, the silicone oil in the casing 4 is returned smoothly and rapidly to the oil reservoir 18.

On the other hand. the silicone oil is delivered from the oil reservoir 18 to the casing 4 through the oil supply channel 8, 22 and this can be made more smoothly by additionally providing at least one oil supply channel 4a and oil supply port 7a.

Other operations and effects of the third embodiment are the same as those of the f irst embodiment previously described above.

In the above-mentioned embodiment, the dam 25, illustrated as an example of the pumping system, located near the oil supply port 7a on the circumferential wall of the casing 4. However, for further improving the pumping function, the dam 25 may be formed into a generally L-shaped cross sectional configuration as shown in Fig. 10(a), (b), or into a generally U-shaped cross sectional configuration as shown in Fig. 10(c). The oil supply port 7a is arranged to the side on the outer circumference of the casing 4 in this modified embodiment.

Explanation will now be made of other embodiments in which the dam as the pumping mechanism is loosely attached tot he recess 51 disposed in the driving disc 5 with reference to Fig. 11 through Fig. 14.

A recess 27 is disposed to the outer circumferential wall of a driving disc 5 on this side of a dam 25, which serves to pressurize the oil collected by the dam 25 to be more effectively supplied to an oil supply port 7a. As shown in Fig. 11(b), if the side of the oil supply port 7a is opened, while the axial opposite side is closed, the pressurizing ef f ect on the oil to the oil supply port 7a disposed on the 23 side of the casing 4 is further improved. The dam 25 is always brought into intimate contact with the opposing inner circumferential wall of the casing 4 upon rotational driving due to centrifugal force and/or tension with a-spring 28.

Further, such dams 25 may be formed at a plurality of positions on the outer circumferential wall surface of the driving disc 5, as necessary, and the several oil supply ports 7a may be arranged. Further, for improving the effect of the centrifugal force, the dam 25 may be provided with a weight 25a as shown in Fig. 12, or the dam itself may be formed as a weight. It is particularly effective in a case, shown in Fig. 9, where the oil supply pipe 16 is connected on the side of the rotational shaft 2 and the oil is supplied or delivered through the hole 5a to the driving disc 5 as shown in Fig. 9. If a sliding member 25b is located on the side in sliding contact with the inner circumferential wall surface of the casing 3 as shown in Fig. 13, it is particularly effective in a case of combining the embodiments shown in Fig. 8 and Fig. 9 together, that is, in a case where the through hole 5a is disposed to the driving disc 5, while the oil supply port 7a is disposed on the side of the casing 4 in order to simultaneously supply and deliver the oil on the side of the rotational shaft 2 and the side of the casing 4.

Further, dam 25 may be constituted, as shown in Fig. 14, with three divided pieces, in which both sides of a central piece 251 are formed with a tapered surface converging toward the 24 outside, and each surface of the side members 251c is formed into such a tapered surface as substantially mating the tapered surface of the central piece 251a. That is, by setting the outer width (1) for each of the side pieces 251b, 251c and the other width (L) f or the outer side of the central piece 25' into a relation: (L) > (1), if abrasion is caused due to the friction between the central piece 251a and the side pieces 251b, 25'c with the inner circumferential wall surface of the casing 4, the central piece 251a is abraded preferentially thereby always obtaining a constant sealing effect due to the edge effect by the tapered surface of the central piece 251a. 281 denotes a spring for outwardly biasing the central piece 251a, which may be replaced with a weight as shown in Fig. 12.

Further, the pumping mechanism is not restricted only to that described above but it may be modified, for example, such that a plurality of gear teeth 29 such as of spur or bevel gear are arranged at the outer circumferential wall of the driving disc 5 as shown- in Fig. 15(a), (b) or such that a plurality of recessed grooves 30, each extending radially, are formed at least on one side to the outer circumferential portion of the driving disc 5 as shown in Fig. 16(a), (b), or such that fins 31 are disposed as shown in Fig. 17(a), (b). Further, the pumping effect can also be attained by forming recessed grooves 32 extended in the radial direction at least to one inner side on the outer circumference of the casing 4 as shown in Fig. 18(a), (b).

c Further, a pumping mechanism can also be attained by combining the gears 29, dam 25, fins 31, recessed grooves 30, 32 described above.

As described above, oil can be delivered extremely smoothly from the torque transmission chamber 7 by disposing various kinds of pumping mechanisms, and the oil can be supplied extremely smoothly to the torque transmission chamber 7 by separately disposing the oil supply channel 4a and the oil supply port 7b, so that the volume of the pump 17 and the motor 20 for driving the pump 17 can be reduced.

Description will now be made of a fourth embodiment. The fourth embodiment includes a data calculation means using at least the rotation rate of the fan, the rotation of the rotational shaft and the temperature of cooling water supplied to the cooling device as control signals and calculating control data regarding the control of the oil supply means and. based on these signals. This embodiment is adapted so that the oil supply means is driven based on the control data obtained from the data calculation means.

Other components of the fourth embodiment are the same as those of the first embodiment described previously. In this fourth embodiment, shown in Fig. 19, a fan velocity signal Nf for the rotation rate of the fan, an engine velocity signal Ne of the rotation rate of the rotational shaft and a water temperature signal Tw for the temperature of the cooling water of the 26 cooling device are inputted as control signals S to a control device 21. In a characteristic data calculation circuit of the control device 21, fan velocity - engine velocity characteristic data (A), fan velocity - cooling water temperature characteristics data (B) and engine velocity - time characteristic data (C) shown in Fig. lg(D) are calculated as the characteristic data based on the above-mentioned control signals.

Control data are calculated based on the characteristic data (D) ((A), (B), (C)) and the control signals S (Ne, Tw, Nf) in the control data calculation circuit of the control device 21, and the motor 20 is controlled based on the resultant control data to control the supply or delivery operation of the oil. that is, at step S11 in Fig. 19, it is decided whether or not the engine is in an accelerated stated based on the engine velocity signal Ne and the engine velocity - time characteristic data (C) according to the conditional relation: dNe/dt > dne/dt. If the judgement made at step S11 is YES, the process proceeds to step S12, in which the fan velocity Nf is set to the minimum fan velocity Noff as: Nf = Noff and then the process proceeds to a step S15. Depending on the demanded characteristics of a vehicle, it may also be adapted, for example, as below. That is, if the judgement made at step S11 is NO, the process proceeds to step S12 during maintenance of a high rotation rate of the engine during acceleration upon starting and/or after acceleration, or the process is maintained at step S12 for a predetermined period of time after t, 27 issue of a Noff signal. Alternatively, even if the decision made at step Sll is YES, the process may be returned to step S13 while the temperature of the cooling water is excessively high and/or the air conditioner is in the ON state and the number of rotation of the engine is relatively low. Further, the process may proceed to step S15 setting as Nf = Non. Then, at step S15, control is determined based on the comparison between the fan velocity signal Nf and the inputted fan calculation velocity signal velocity Nf and, depending on the decision made at step S15, current is supplied at a step S16 to the motor 20.

If the decision made at step S11 is NO, the process proceeds to step S13 in which the maximum fan velocity Non and the minimum fan velocity Noff are calculated and then the process proceeds to step S14 in which the fan calculation velocity is calculated by nf = f(Noff, Non, Tw, T1, T2). For instance, in a case of controlling the fan velocity relative to the temperature of the cooling water in a linear system, calculation is carried out according to:

nf = Noff + (Non - Noff) X Tw - TI/T2 - T1 Then, the process proceeds to step S15, in which control is determined based on the comparison between the resultant calculated fan velocity nf and the inputted fan velocity signal Nf and, according to the decision at step S15, current is supplied to the motor 20 at step S16.

28 Other operations and effects of the fourth embodiment are the same as those of the first embodiment previously described.

Description will now be made of a fifth embodiment with reference to Figs. 20 and 21.

As shown in Fig. 20, a disc-shaped disc 5 is secured to one end of a rotational shaft 2, and a fan 15 is secured to the other end of the shaf t. A cylindrical casing 4 of a short length and a large diameter is rotatably attached, with the disc 5 being incorporated at its inside, to the rotational shaft 2 by way of bearings 3. The rotational shaft 2 is supported substantially at its middle portion by way of bearings 40 disposed in a bracket 9 to a stationary portion such as a car body or an engine block. An oil channel 2a axially passing though the rotational shaft 2 is formed at the axial centre of the rotational shaft 2 in communication with the end face on the side of the disc 5, and the other end of the oil channel 2a is closed by a plug 26. The outer end of the oil channel 2a is in communication by way of bearings 11 and through a take-out pipe 13 with an oil supply pipe 16. At least one through hole 5a in communication with the oil channel 2a. is arranged in relation to the disc 5 such that the outer circumferential surface is opened to the torque transmission chamber 7, and a torque transmission gap 71 is formed between the outer circumferential surface of the disc 5 and the inner circumferential surface of the casing 4 opposed to the outer circumferential surface of the disc. Furthermore,, a rotational 1 29 shaft of an engine 1 as a driving section is connected by means of a flexible joint 1A comprising a torque pipe, a spiral spring and a slitted hollow shaft to the casing 4.

A pump 17 driven by a motor 20 is connected to the oil supply pipe 16, and the pump 17 is connected to an oil reservoir 18 accumulating a silicone oil. A cooling water temperature sensor 24, for detecting the temperature of cooling water for the engine 1 is attached to the engine 1, a rotation sensor for detecting the rotation rate of the casing 4 is attached to the casing 4 and a fan rotation sensor 22 for detecting the rotation of the fan 15 is attached to the blower 15 respectively. Respective output terminals for the cooling water temperature sensor 24, the rotational number sensor 23 and the fan rotational number sensor 22 are connected to a control device 21 for controlling the rotation of the motor 20.

With such an arrangement, the rotation of the engine 1 is transmitted by way of the flexible joint 1A to the casing 4 with no impact shocks, stably and with no vibration to rotate the casing 4 by way of the bearings 3 around the rotational shaf t 2 as the centre of rotation. On the other hand, the motor 20 is driven under control by the control device 21 that operates by receiving the detection signal from the cooling water temperature sensor 24, the detection signal from the rotation sensor 23 and the detection signal from the fan rotational number sensor 22. The pump 17 is operated by the rotation of the motor 20 to supply silicone oil in the oil reservoir 18 by way of the oil supply pipe 16, the output pipe 13, the oil channel 2a and the through hole 5a to the torque transmission chamber 7 in the casing 4.. or to return the silicone oil in the torque transmission chamber 7 by way of the above-mentioned flow channels into the oil reservoir 18. Then, since the transmission rate of the rotational torque of the casing 4 to the disc 5 is adjusted depending on the amount of silicone oil in the torque transmission gap 7', the rotational velocity of the fan 15 rotated by the rotation of the disc 5 can always be controlled to a desired value.

The present invention is not restricted only to the embodiment shown in Fig. 20, but it is also applicable to a fluid clutch of a type shown in Fig. 21, in which driving force of an engine 1 is transmitted to a disc 5 and the transmission torque is transmitted to the casing 4 by way of a torque transmission gap 7' and torque transmission chamber 7.

In Fig. 21,- the rotation of the engine 1 is transmitted by way of a flexible joint 1A to a driving shaft 51 to rotate the disc 5. The rotation of the disc 5 is transmitted by means of the silicone oil in the torque transmission gap 71 of the torque transmission chamber 7 to the casing 4. The casing 4 is rotatably supported by way of bearings 41 on the stationary portion such as a car body or an engine block.

The inside of the casing 4 is bisected into a torque transmission chamber 7 and an oil chamber 8 by a partition wall 1 31 6, in which the oil channel 8 is connected by way of a output pipe 13 with an oil supply pipe 16, which is in communication at the outer circumferential thereof with channel 8a, 8b and opened to the torque transmission chamber 7. A dam 25 or the like having a pumping function is disposed behind the opening of the communication channel 8a at the inner circumferential surface of the casing 4.

Bearings 3 and 3a are disposed respectively between the output pipe 13 and the casing 4 and between the casing 4 and the driving shaft 51, and bearings 26 are disposed for rotatably supporting the casing 4 to the stationary portion, which may be used instead of or together with, the bearings 101.

The operation of the embodiment shown in Fig. 21 is substantially identical with that of the embodiment shown in Fig. 20, in which the silicone oil is supplied to the torque transmission chamber 7 by the pump 17 through the oil channel. 8 and the communication channels 8a, 8b, while the silicone oil is delivered through the communication channel 8a by reverse rotation of the pump 17 and the pumping function of the dam 25 or the like. In a case where the pump is not actuated, the silicone oil enters by the dam 25 by way of the communication channel 8a to the oil channel 8 and circulates from the oil channel 8 by way of the communication channel 8b to the torque transmission channel 7.

The operation of the fifth embodiment is the same as the 32 operation of the first embodiment previously described with reference to Fig. 3 through Fig. 5.

In the fifth embodiment, since the casing 4 or the disc 5 is supported on the stationary portion, a flexible joint transmitting only the rotation of the engine 1 can be used and, accordingly, even in a driving transmission by way of direct coupling with the crank shaft of the engine, bearings attached to the rotational shaft 2 are free from direct impact shocks or vibrations upon driving the engine 1, which can extend the operational life and improve the durability of bearings which have a high manufacturing cost, as well as a problem in view of the production cost can be overcome. Other effects of the fifth embodiment are identical with those of the first embodiment previously described.

As has been described above specifically, according to the present invention, since oil supplied from an outside to a torque transmission gap defined between a driving disc and a casing is controlled depending on the driving conditions in the driving section, it is possible to transmit the driving torque of the driving disc corresponding to the driving conditions under an optimum transmission state to the casing and to conduct optimum clutch operation under various kinds of driving conditions, so that various advantageous effects can be achieved such as reduction of fan noises, economy of fuels, as well as improvement of the acceleration performance.

33 Further, in accordance with the present invention, since the disc or the casing is rotatably supported on a stationary portion, the burden on bearings attached to the rotational shaft can be moderated and, since the fluid clutch and the engine are connected by means of a flexible joint, the bearings do not undergo impact shocks or the vibrations upon driving and the working life dan be extended and the entire durability is improved.

S

Claims

1. A fluid clutch comprising a driving section, a rotational shaft rotated by the driving section, a driving disc rotationally driven by the rotational shaf t, a casing in which the driving disc is incorporated and which is rotatable about the rotational shaft, a f an attached to the casing, and an oilfilled torque transmission gap defined between the driving disc and the casing for transmitting the driving torque of said driving disc to the casing, wherein an oil supply means is arranged for supplying oil from the outside to the inside of the casing and the oil supply means is connected by way of an oil supply pipe to the casing.

2. A fluid clutch comprising a driving section, a rotational shaft rotated by the driving section, a cooling device for cooling the driving section, a driving disc rotationally driven by the rotational shaft, a casing in which the driving disc is incorporated and which is rotatable about the rotational shaft, a fan attached to the casing, and an oilfilled torque transmission gap defined between the driving disc and the casing for transmitting the driving torque of the driving disc to the casing, wherein the fluid clutch comprises an oil supply means for supplying oil f rom the outside to the inside of the casing, and a control means for controlling the supply of oil by the oil supply means at least based on the rotation rate of the fan, the rotation rate of the rotational shaft and the temperature z 1 of cooling water of the cooling device.

3. A f luid clutch according to claim 1 or 2, wherein a breather f or causing a gas to be moved between the torque transmission gap and atmospheric air is arranged adjacent the torque transmission gap.

4. A fluid clutch according to claim 1 or claim 2, wherein a pumping mechanism is arranged at least one of the outer circumferential side of the driving disc and the inner circumferential wall of the casing.

5. A fluid clutch according to claim 4, wherein the pumping mechanism comprises a dam disposed near the oil supply port of the casing.

6. A fluid clutch according to claim 5, wherein the dam has a substantially L- or U-shaped cross sectional configuration.

7. A fluid clutch according to claim 4,, wherein the pumping mechanism comprises a dam loosely attached to a recessed portion formed at the outer circumferential wall of the driving disc.

8. A fluid clutch according to claim 7, wherein a recessed portion is further formed before the dam and the outer circumferential wall of the driving disc.

3 P

9. A fluid clutch according to claim 7, wherein the dam comprises three divided portions, in which.each of the sides of a central portion has a tapered surface converged toward the outside, while both of the side portions has a tapered surface on one side which contacts the tapered surface of the central portion.

10. A f luid clutch as defined in claim 4, wherein the pumping mechanism comprises teeth of a spur or bevelled gear arranged at the outer circumferential wall of the driving disc.

11. A fluid clutch according to claim 4, wherein the pumping mechanism comprises a plurality of f ins or recessed grooves extending radially, and arranged on at least on side of at least the outer circumferential portion of the driving disc.

12. A I luid clutch according to claim 4, wherein the pumping mechanism comprises a plurality of recessed grooves extending radially and arranged on at least one inner side of at least the outer circumferential portion of the driving disc.

13. A fluid clutch according to claim 4, wherein the oil supply means comprises at least one oil supply channel and oil supply port in communication with the oil supply pipe and arranged in the casing.

37

14. A fluid clutch comprising a driving section, a rotational shaft rotatable by the driving section, a cooling device for cooling the driving section, a driving disc rotatable by the rotational shaf t, a casing in which the driving disc is incorporated and which is rotatable about the rotational shaf t, a f an attached to the casing, and an oilfilled torque transmission gap defined between the driving disc and the casing for transmitting the driving torque of the driving disc to the casing, wherein the fluid clutch comprises an oil supply means for supplying oil by way of the oil supply pipe from the outside to the inside of the casing, a data calculation means for calculating control data using at least the rotation rate of the fan, the rotation rate of the rotational shaft and the temperature of the cooling water of the cooling device as control signals and calculating control data regarding the control for the oil supply means based on the control signal, and a control device for driving the oil supply means based on the control data obtained from the data calculation means.

15. A fluid clutch comprising a casing a disc incorporated therein, a driving section connected by way of a flexible joint to either one of the casing or the disc, bearings for rotatably supporting the other of them to a stationary portion and an oil supply means for supplying oil from the outside to a torque transmission gap defined between the opposing surfaces of the casing and the disc.

-51

16. A fluid clutch comprising a casing a disc incorporated therein, a driving section connected by way of a flexible joint to either one of the casing or the disc, bearings for rotatably supporting the other of them to a stationary portion and an oil supply means for supplying oil from the outside to a torque transmission gap defined between the opposing surfaces of the casing and the disc. and a control means for controlling the supply of oil by the oil supply means at least based on the number of rotation of the fan, the rotation rate of the casing and the temperature of cooling water in the driving section.

17. A fluid clutch substantially as described herein and as illustrated in the accompanying drawings.

Published 1992 at The Patent Office. Concept House. Cardiff Road. Newport. Gwent NP9 1 RH. Further copies may be obtained f) Gni Sales Branch. Unit 6. Nine Mile Point. Cwmifelinfhch. Cross Keys. Newport. NPI 7HZ. Printed by Muld lex techniquesltd. St Mar Cray. Kent. p