JPH04194423A - Liquid clutch - Google Patents

Abstract

PURPOSE:To adjust an oil amount with high accuracy by providing a means having a pumping mechanism to supply oil from the outside through an oil transportation pipe into a case and controlling the oil supply on the basis of the rotational frequency of a driven body and the temperature of cooling water. CONSTITUTION:A case 4 is divided into two, a torque transmitting chamber 7 and an oil reservoir consisting of an oil transportation paths 8, 4a, and the torque transmitting chamber 7 is connected to the oil transportation path 8 through a communicating path 10. A dam 25 as a pumping mechanism is provided in the position of an oil sending port 7a. A pump 17 is driven by an operating motor 20 to send oil into the case 4. An amount of the sent silicon oil or an amount of silicon oil returned from the case 4 to an oil tank 18 is set on the basis of detecting data of a cooling water temperature sensor 24, rotation sensor 23 and fan rotational frequency sensor 22.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention is a liquid clutch, in particular, a liquid clutch that transmits the driving torque of the driving disk to the case using oil filled in the torque transmission chamber of the case where the driving disk and the fan are attached. The present invention relates to a liquid clutch.

(Prior technology) The inside of the case is divided into a torque transmission chamber and an oil reservoir chamber by a partition plate, a drive disk is provided in the transmission chamber so as to be rotatable by the drive of the drive unit, and the oil in the oil reservoir chamber is formed on the partition plate. For example, Japanese Patent Publication No. 63-21048 discloses a coupling device having a structure in which oil is supplied to a transmission chamber through an outflow adjustment hole and oil in the transmission chamber is returned to an oil reservoir chamber through a circulation path. According to this type of coupling device, the driving torque of the drive disk is transmitted to the case plate by oil supplied from the oil reservoir chamber to the transmission chamber, and a fan attached to the case rotates, thereby cooling an automobile engine, for example. be exposed.

(Problem to be Solved by the Invention) In the conventional coupling device described above, the atmospheric temperature is detected by a bimetal, and when this temperature rises, the opening degree of the outflow adjustment hole is increased to increase the amount of oil in the transmission chamber. The fan speed is increased to increase the cooling effect by rotating the fan at high speed.

However, automobile engines are driven under various conditions. For example, while driving on a highway, the drive disk rotates at high speed, but since the air cooling effect of the traveling wind is enhanced, it is not necessary to rotate the fan at an extremely high speed. If the fan speed is high during a cold start or if the fan speed is high during a cold start, it will inhibit warm-up operation and generate fan noise, so the fan should be rotated at a low speed. Control is required to keep the temperature constant without changing the temperature. In order to meet this demand, it is insufficient to control the amount of oil based only on the ambient temperature.

Furthermore, in the conventional system, since the oil for transmitting torque is sealed in the case, the oil easily deteriorates and the amount of oil cannot be adjusted with high precision, which limits control.

The present invention has been made in view of the current state of this type of liquid clutch as described above, and its purpose is to provide a liquid clutch that accurately controls the amount of oil by adjusting the amount of oil with high precision according to various operating conditions. Our goal is to provide the following.

(Means for solving problems).

In order to achieve the above object, a first basic invention includes a driving section, a rotating shaft that is rotated by the driving of the driving section, a driving disk that is rotationally driven by the rotating shaft, and a driving disk that is housed in the driving disk. a case rotatably disposed around the rotation axis; a driven body attached to the case and driven by the rotation of the case; and a silk transmission chamber between the drive disk and the case filled with the case; In a liquid clutch having oil for transmitting the driving torque of the driving disk to the case, an oil supply means for supplying the oil into the case from the outside via an oil pipe, an outer peripheral side of the driving disk and the case. The structure includes a pumping mechanism provided on at least one of the inner circumferential walls of the pump.

Similarly, in order to achieve the above object, a second basic invention includes a driving section, a rotating shaft that is rotated by the driving of the driving section, a cooling device that cools the driving section, and a rotating shaft that is rotated by the rotating shaft. a drive disk to be driven; a case in which the drive disk is housed and rotatably arranged around the rotation axis; a driven body attached to the case and driven by rotation of the case; In a liquid clutch having oil that is filled in a torque transmission chamber between a disk and the case and transmits the driving torque of the drive disk to the case, oil is supplied from the outside to the torque transmission gap via an oil pipe. a supply means; a pumping mechanism provided on at least one of the outer circumferential side of the drive disk and the inner circumferential wall of the case; and at least a rotational speed of the driven body;

The apparatus is configured to include a control means for controlling the supply of the oil by the oil supply means based on the rotation speed of the rotating shaft and the temperature of the cooling water of the cooling device.

(Function) With this configuration, in the first basic invention, the driving torque of the driving disk is transferred from the outside via the oil supply pipe to the torque transmission chamber between the driving disk and the case. Oil to be transmitted to the case is supplied, or oil is sent to the outside from the torque transmission chamber. Fresh oil is accurately and accurately supplied from the oil supply means, and since the torque transmission chamber is provided with a pumping mechanism, smooth oil feeding and discharging is performed.

Further, in the second basic invention, in addition to the effects of the first basic invention, the control means controls at least the rotational speed of the driven body and the rotational speed of the rotating shaft rotated by the drive of the drive unit. The supply of oil to the torque transmission chamber is controlled based on the temperature of the cooling water of the cooling device, and smooth oil delivery is performed by the pumping mechanism. In this way, the oil amount is controlled accurately and accurately, and the driven body is driven in accordance with various operating conditions.

(Example) · Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

FIG. 1(a) is an explanatory diagram showing the configuration of one embodiment of the present invention, in which a large diameter and short case 4 is connected to a rotating shaft 2 which rotates by the drive of an engine 1, which is a drive unit, via a bearing 3.
is attached rotatably about the axis of the rotating shaft 2. A disk-shaped drive disk 5 is fixed to an end of the rotating shaft 2 inserted into the case 4.

Furthermore, inside the case 4, a torque transmission chamber 7 and two are separated by a partition wall 6.
It is divided into two oil reservoir chambers consisting of two oil feed passages 8 and 4a,
The torque transmission chamber 7 and the oil feed path 8 are connected to each other through a communication path 10. The drive disk 5 is connected to the torque transmission chamber 7.
A torque transmission gap is formed between the outer peripheral surface and side surface of the drive disk and the inner peripheral surface and side surface of the torque transmission chamber 7 facing therebetween.

Further, a dam 25 as a pumping mechanism is provided at a position of the oil feed lower a which communicates the communication passage 10 and the torque transmission chamber 7 on the inner circumferential wall of the case 4, and this dam 25 receives oil from the torque transmission chamber 7 side. Pump oil to the feed path 8 side. A take-out pipe 12 is attached to the center of the oil feed path 8, and a case 4 is connected to the take-out pipe 12 via a bearing 13.
is rotatably attached. In this way, the case 4 is rotatably attached via the bearing 3.13 around the axes of the rotating shaft 2 and the extraction tube 12,
A fan 15 is fixed to the case 4 as a driven body.

On the other hand, an oil feed lower b is provided on the inner circumferential wall of the case 4, preferably substantially opposite to the oil feed lower 7a, and an oil feed N4a is provided between the oil feed lower b and the take-out pipe 12 in the case 4. It is formed.

One end of an oil feed pipe 16 is fixed to the extraction pipe 12, and the other end of the oil feed pipe 16 is connected to an oil tank 18 via a pump 17, and silicon oil is stored in the oil tank 18. The pump 17 is driven by a motor 20,
Silicone oil is fed into the case 4 from the oil tank 18 via the oil feed pipe 16 and oil feed path 8.4a, or silicone oil is fed from inside the case 4 through the oil feed path 8.4a and the oil feed pipe 16.
It has a function of sending the oil back to the oil tank 18 via. The rotation of the motor 20 is controlled by a control signal from a control device 21, and this control device 21 includes a detection signal from a fan rotation speed sensor 22 that detects the rotation speed of the fan 15, and a rotation speed sensor that detects the rotation speed of the rotating shaft 2. 23 and a detection signal from a cooling water temperature sensor 24 that detects the temperature of the cooling water of the engine l are supplied.

The present invention is not limited to the above-mentioned embodiment, and the oil pipe 16 can also be connected to the rotating shaft 2 side as shown in FIG. 1(b).

That is, a swivel joint 25 is provided on the rotating shaft 2, an oil pipe 16 is connected to the swivel joint 25, and one or more oil passages 2a, 2 are connected to the rotating shaft 2 in the radial direction.
a, . . . and oil f! which communicates with the oil passage at the center of its axis.
42b, and at least one through hole 5a that communicates with the oil passage 2b, passes through the drive disk 5 in the radial direction, and is open to the outer circumferential surface thereof, and the rear side of the through hole 5a in the rotational direction. A notch 5' is provided in the outer circumferential wall of the drive disk 5, and a dam 25 is loosely attached to this notch 5', and the other configuration is the same as that in FIG. 1(A). . Note that 26 is a plug that closes the end of the oil passage 2b.

The present invention can also be combined with the embodiment shown in FIG. 1(A) and the embodiment shown in FIG. 1(D). That is, the oil supply pipe 16 is connected to the case side and the rotating shaft 2 side, and the pump 17 is used to supply or send oil to the torque transmission chamber, or oil is supplied from the rotating shaft 2 side and sent out from the case 4 side, On the other hand, case 4
It can also be configured to be supplied from the side and sent out from the rotating shaft 2 side.

Next, the operation of the embodiment having the configuration shown in FIGS. 1(a) and 1(b) will be described with reference to the drawings.

FIG. 2 is a flowchart of the operation of the embodiment, FIG. 3 is a characteristic diagram of the operation of the embodiment, and FIG. 4 is a characteristic diagram showing the relationship between the rotation speed of the input shaft and the fan rotation speed of the embodiment.

In the embodiment, detection data from the cold water temperature sensor 24, rotation speed sensor 23, and fan rotation speed sensor 22 is taken into the control device 21 at predetermined time intervals and written into the memory of the control device 21. In step S1 in FIG. 2, the current water temperature data taken in from the cooling water temperature sensor 24 is compared with the water temperature data from a predetermined time ago, and it is determined whether the difference between the two data is greater than a preset reference value. I can pass. In this determination, the allowable upper limit and the allowable lower limit of the cooling water temperature of the engine 1 are used as reference.

If the determination in step S1 is YES, the process advances to step S2, where the current rotation speed data taken in by the rotation speed sensor 23 is compared with rotation speed data from a predetermined time ago, and it is determined whether or not there is a sudden acceleration state. It will be done. Step S
If the determination in step 2 is NO, the process proceeds to step S3, where the current fan rotation speed data taken in by the fan rotation speed sensor 22 is compared with the rotation speed data from a predetermined time ago, and the difference between both data is set in advance. A determination is made as to whether it is larger than a reference value.

If the determination in step S3 is NO, the process proceeds to step S4, where the pump 17 is driven by the motor 20 operated by the control signal from the control device 21, and the oil tank 18
silicone oil is sent into the case 4 via the oil feed pipe 16 and the oil feed path 8.4a. If the determination in step S3 is YES, the process proceeds to step S5, where the pump 17 is driven by the motor 20 operated by the control signal from the control device 21, and the silicone oil in the case 4 is pumped by the dam 25 and the oil is pumped. The oil is returned into the oil tank 18 via the feed path 8 and the oil feed pipe 16.

In this case, the suction performance of the pump 17 is increased by the pumping action of the dam 25 provided between the oil feed lower a and the drive disk 5, and the silicone oil in the case 4 is returned to the oil tank 18 smoothly and in a short time. It can be done.

In step S3. From oil tank 18 to case 4
The amount of silicone oil sent into the case 4 or the amount of silicone oil returned from the inside of the case 4 to the oil tank 18 is determined by the cooling water temperature sensor 24, the rotation speed sensor 23, and the fan rotation speed sensor 2.
It is set based on the detection data of 2.

If the determination in step S1 is NO or the determination in step S2 is YES, the process advances to step S8, where it is determined whether the silicone oil has been returned from the case 4 to the oil tank 18. Then, the determination in step S8 is YES.
If so, the process proceeds to step S7 and that state is maintained,
If the determination in step S8 is NO, the process proceeds to step S6, where the pump 17 is controlled by a control signal from the control device 21.
is switched and driven to return silicone oil from the case 4 to the oil tank 18.

The duration of the silicone oil return operation in Stella 7S7 or the amount of silicone oil sent to the case 4 in step S6 is set based on the detection data of the cooling water temperature sensor 24, rotation speed sensor 23, and fan rotation speed sensor 22. be done.

In the embodiment, as shown in FIG. 3, when the temperature of the cooling water of the engine 1 is near the upper limit water temperature and the temperature of the cooling water increases significantly, the fan rotation speed is increased. Conversely, if the temperature of the cooling water drops, the fan speed will be reduced. Also, if the rotation speed of the rotating shaft 2 suddenly increases, as shown by the dotted line,
The fan rotation speed is controlled in the direction of lowering it, and the fan rotation speed is reduced as shown by the diagonal lines.

Furthermore, in the rotational characteristics of the rotating shaft 2 and the fan 15 shown in FIG. 4, when the coolant temperature of the engine 1 is normal, control is performed in the B region, but when the coolant temperature exceeds the upper limit water temperature, the control is performed in the A region. control is performed.

By controlling in this way, in the embodiment, the amount of silicone oil in the case 4 can be increased by sending the silicone oil into the case 4 from the oil tank 18 or returning the silicone oil from the case 4 to the oil tank 18. It is varied with precision and over a wide range.

In this case, since the dam 25 having a pumping action is provided between the oil feed lower a and the drive disk 5, the silicone oil in the case 4 is returned to the oil tank 18 smoothly and in a short time. On the other hand, silicone oil is fed from the oil tank 18 into the case 4 through the oil feed path 8, but this can be done more smoothly if at least one oil feed path 4a and oil feed lower a are separately provided.

In this way, an appropriate amount of silicone oil corresponding to the temperature of the cooling water of the engine 1, the rotation speed of the rotating shaft 2 (proportional to the rotation speed of the engine 1), and the rotation speed of the fan 15 is supplied to the oil feed 1118.4.
a into the torque transmission chamber 7, or the transmission chamber 7
The silicone oil is extracted from the torque transmission chamber 7 through the oil feed passages 8 and 4a by the dam 25 so that the amount of silicone oil therein becomes an appropriate amount.

Then, the torque of the drive disk 5 is transmitted to the case 4 through an appropriate amount of silicone oil in the transmission chamber 7, and the fan 15 rotates. - Note that in the above embodiment (in this case, the pumping mechanism is the oil feed lower a on the inner peripheral wall of the case 4).
In order to further improve the pumping function, the dam 25 may be formed to have an abbreviated cross section as shown in FIGS. It can also be formed into a substantially U-shaped cross section as shown in FIG. In the second embodiment, the oil feed lower a is provided on the outer circumferential side of the case 4.

Furthermore, the dam 25 as a pumping mechanism is connected to the drive disk 5.
FIGS. 7 to 11 (two examples will be explained) showing still another embodiment in which the device is loosely attached to the notch 5' provided in the.

27 is a recess provided in the outer peripheral wall of the drive disk 5 on the front side of the dam 25, and is provided in order to pressurize the oil collected by the dam 25 and more effectively send it to the oil feed lower a. If the lower oil feed side is opened and the opposite side in the axial direction is closed as shown in FIG. Improve further.

During drive rotation, the centrifugal force and/or the tension of the spring 28 causes the lid dam 25 to constantly come into tight contact with the inner circumferential wall surface of the opposing case 4.

Furthermore, if necessary, dams 25 may be formed at a plurality of locations on the outer circumferential wall surface of the drive disk 5, and the oil feed lower a may be configured with a plurality of passages. 25 is provided with a weight body 25a as shown in FIG. 9, or the dam itself is configured as a weight body, especially the first
This is effective when connecting the oil pipe 16 to the rotating shaft 2 side as shown in Figure (B) to supply and send oil to the drive disk 5 through the through hole 5a.
When the sliding member 25b is provided on the sliding portion side with the inner peripheral wall surface of
In particular, the combination of the embodiments shown in FIG. 1(a) and FIG. 1(b), that is, in order to simultaneously supply and send oil from the rotating shaft 2 side and the case 4 side, a through hole 5a is formed in the drive disk 5, and a through hole 5a is formed in the case. This is effective when the oil feed lower a is provided on the 4th side.

Furthermore, as shown in FIG. 11, the dam 25 is constructed from three pieces,
Both sides of the central piece 25°a are formed into tapered surfaces that taper outward, and one side of the both side pieces 25"b, 25°C is a tapered surface that substantially coincides with the tapered surface of the central piece 25"a. That is, the outer width of both sides is 25°b and 25°C (
L) and the outer width (1) of the center piece 25”a as (L)〉(1
), the central piece 25゛a and the one side piece 25'
b, 25'c, even if wear occurs due to friction with the inner circumferential wall surface of the case 4, the center piece 25°a wears out first, and the center piece 2
A constant sealing effect can always be obtained due to the wedge effect due to the 5'a taper surface. In addition, 28゛ is the center piece 25゛a
This is a spring that urges the body outward. Instead of this spring, a weight body as shown in FIG. 9 may be provided.

Furthermore, the pumping mechanism is not limited to the above embodiment;
As shown in FIGS. 2(a) and (b), a plurality of spur or oblique gear teeth 29 may be provided on the outer peripheral wall of the drive disk 5, or as shown in FIGS. 13(a) and (b). drive disk 5
A plurality of concave grooves 30 extending in the radial direction are formed on at least one side or both sides of the outer periphery, or as shown in FIG.
It is also possible to provide fins 31 as shown in (b) and (b).

Furthermore, as shown in FIGS. 15(a) and 15(b), a pumping action can also be achieved by forming a groove 32 extending in the radial direction on one or both of the inner surfaces of at least the outer circumference of the case 4.

Furthermore, a pumping mechanism can be constructed by appropriately combining the gear teeth 29, dam 25, fins 31, and grooves 30, 32 described above.

In this manner, according to the present invention, the optimal silicone oil corresponding to the temperature of the cooling water of the engine 1, the rotation speed of the engine 1, and the rotation speed of the fan 15 is present in the transmission chamber 7, as shown in FIG. Control is performed so that the rotational speed of the fan 15 does not increase significantly.

The temperature of the cooling water in the engine 1 is also kept almost constant without overshooting, and the noise from the fan 15 is also reduced as control is performed under optimal conditions that are suitable for cold starts, driving on highways, and sudden acceleration. This prevents unnecessary fuel consumption. In addition, since the pumping mechanism is provided, the oil can be sent out from the torque transmission chamber 7 extremely smoothly.
In addition, by separately providing the oil feed i4a and the oil feed lower b, the oil can be supplied to the torque transmission chamber 7 very smoothly as well as the oil is sent out.
The motor 20 that drives the motor 20 can be downsized.

In addition, in the embodiment, the oil amount in the case is controlled based on the engine cooling water temperature, the engine rotation speed, and the fan rotation speed, but the present invention is not limited to the embodiment. For example, in addition to these, driving air volume, outside temperature,
It is also possible to adopt a configuration in which intake air temperature, vehicle speed, throttle opening, air pressure, presence or absence of knocking, air conditioner condition, exhaust brake condition, etc. are added to the control factors.

(Effects of the Invention) As explained in detail above, the present invention controls the oil supplied from the outside to the drive disk and the torque transmission chamber of the case in accordance with the drive conditions of the drive unit. The drive torque of the drive disk is transmitted to the case in the optimal transmission state according to the conditions, and the clutch operation is optimal under various drive conditions, reducing fan noise, saving fuel, and improving acceleration. Many effects can be expected, including improved performance.

[Brief explanation of the drawing]

FIG. 1(a) is an explanatory diagram of one embodiment showing the overall configuration of the present invention, FIG. 1(b) is an explanatory diagram of main parts of another embodiment, FIG. 2 is a flowchart showing the operation, and FIG. 3 4 is an operating characteristic diagram, FIG. 5(A) is a sectional view of a main part of still another embodiment of the present invention, FIG. 5(B) is a perspective view of the dam alone in FIG. 5(A), Figure 6 is a perspective view of another embodiment of the dam alone, Figure 7 (a) is an enlarged cross-sectional view of the main part of another embodiment of the pumping mechanism, and Figure 7 (b) is the same as that of Figure 7 (a). A sectional view taken along the line A-A, FIGS. 8 to 10 are views corresponding to FIG. 7 (A) of another embodiment,
FIG. 11 is an enlarged vertical sectional view of the main part of yet another embodiment, and FIG.
Figure (a), Figure 13 (a), and Figure 14 (a) are enlarged vertical sectional views of main parts of still another embodiment of the pumping mechanism, Figure 12 (b), Figure 13 (b), and Figure 14 (b), respectively. Figure 14 (b)
12(a), 1313(() and 1st), respectively.
Enlarged plan view of the main part of Figure 4 (a), Figure 15) and (b)
are enlarged vertical cross-sectional views of main parts of still other embodiments, and B-
It is a sectional view taken along the B line. 1... Engine, 2... Rotating shaft, 4... Cover,
4a, 8... Oil feed path, 5... Drive disk, 6...
- Partition wall, 7... Torque transmission chamber, 7a, 7b... Oil feed port, 10... Communication path, 15... Fan, 16...
Oil pipe, 17... pump, 18... oil tank,
20... Motor, 21... Control device, 22... Fan rotation speed sensor, 23... Rotation speed sensor, 24...
・Cooling water temperature sensor. Patent applicant Usui Kokusai Sangyo Co., Ltd. Figure 1 (B) Figure 2 Figure 3 Figure 4 Figure 5 Figure 5 (A) Figure 5 (B) Figure 6 Figure 12 (A) Figure 12 (B) Figure 13 (a) Figure 13 (b) n Figure 14 (a) Figure 14 (b) Figure 15 (a), Figure 15 (b)

Claims (1)

[Claims] 1. A drive unit, a rotating shaft that rotates by the drive of the drive unit, and a drive disk that is rotationally driven by the rotating shaft;
A case in which the drive disk is housed and is rotatably arranged around the rotation axis, a driven body attached to the case and driven by the rotation of the case, and a space between the drive disk and the case. A liquid clutch having oil that is filled in a silk transmission chamber and transmits the drive torque of the drive disk to the case, an oil supply means for supplying oil from the outside to the torque transmission chamber via an oil pipe, and the drive A liquid clutch comprising a pumping mechanism provided on at least one of the outer peripheral side of the disk and the inner peripheral wall of the case. 2. A drive unit, a rotating shaft that rotates due to the drive of the drive unit, a cooling device that cools the drive unit, a drive disk that is rotationally driven by the rotating shaft, and a drive disk that accommodates the drive disk and that rotates the rotating shaft. a case rotatably disposed at the center; a driven body attached to the case and driven by the rotation of the case; and a torque transmission chamber between the drive disk and the case filled with In a liquid clutch having oil for transmitting driving torque to the case, an oil supply means for supplying oil from the outside to the torque transmission chamber via an oil pipe, and an oil supply means for supplying oil to the torque transmission chamber from the outside via an oil pipe, and an oil supply means for supplying oil to the torque transmission chamber from the outside through an oil pipe, and a pumping mechanism provided on at least one side; and a pumping mechanism that controls the supply of the oil by the oil supply means based on at least the rotational speed of the driven body, the rotational speed of the rotating shaft, and the temperature of the cooling water of the cooling device. A liquid clutch characterized by comprising a control means for controlling the liquid clutch. 3. The liquid clutch according to claim 1 or 2, wherein the oil feed pipe is connected to at least one of a case side and a rotating shaft side. 4. Claim 1, wherein the driven body is a fan.
Or the liquid clutch described in 2. 5. Claim 1 or 2, wherein the pumping mechanism comprises a dam provided near the oil feed port of the case.
Liquid clutch as described. 6. The liquid clutch according to claim 5, wherein the dam has a substantially L-shaped or U-shaped cross section. 7. The liquid clutch according to claim 1 or 2, wherein the pumping mechanism comprises a dam loosely attached to a notch formed in the outer peripheral wall of the drive disk. 8. The liquid clutch according to claim 7, further comprising a recess formed in the outer peripheral wall of the drive disk before the dam. 9. The dam is composed of three divided pieces, both sides of the central piece having an outwardly tapered tapered surface, and both side pieces having a tapered surface on one side that substantially coincides with the tapered surface. The liquid clutch according to claim 7, characterized in that: 10. The liquid clutch according to claim 1 or 2, wherein the pumping mechanism comprises spur gear teeth or oblique gear teeth provided on the outer peripheral wall of the drive disk. 11. The liquid clutch according to claim 1 or 2, wherein the pumping mechanism comprises a plurality of radially extending fins or grooves provided on at least one side of at least the outer periphery of the drive disk. 12. The liquid clutch according to claim 1 or 2, wherein the pumping mechanism comprises a plurality of grooves extending in the radial direction provided on at least one inner surface of at least the outer circumference of the case. 13. The liquid clutch according to claim 1 or 2, wherein the oil supply means includes at least one oil feed path and oil feed port that communicate with the oil feed pipe and are provided in the case.