JPS62167937A - Hydraulic-clutch controller for marine use - Google Patents

Abstract

PURPOSE:To improve the feeling of steering a boat by temporarily reducing the current oil pressure to the first oil pressure and changing the value to the second oil pressure when a clutch is engaged, in some appropriate mode, whereby moderating the shock produced in engagement of the clutch. CONSTITUTION:After a control part 24 forces a motor 25 to hold its driving for a time T2, said part 24 descriminates whether the mode selected by a mode selecting switch 43 is the normal mode N or clattering sound preventing mode L. When the normal mode N is descriminated, the motor 25 is driven and the oil pressure is regulated to the second value P5 and this oil pressure is maintained till the next clutch disengaging time. In a time chart describing the propeller revolution speed, the oil pressure which is transmitted to the hydraulic clutch and the engaged/disengaged state of the clutch, no evidence of a shock is shown so that the clutch can be engaged/disengaged smoothly.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a control device for a hydraulic clutch installed on a ship, and more specifically, when the engine tends to be rotated, such as during trolling fishing, etc. The present invention relates to a control device for a hydraulic clutch installed on a fishing boat, a work boat, or the like that operates at low speed or in a stationary state.

[Problems with conventional technology]

Hydraulic clutches have conventionally been used in marine engines as clutches for switching the rotation of a propeller between forward and reverse directions, or for stopping the rotation of a propeller while the engine is rotating.

When operating this hydraulic clutch, if the hydraulic clutch is suddenly engaged, the propeller may suddenly start rotating, or
Since the rotation is reversed, the gears make noise and cause a shock to the human body, which not only makes the ride uncomfortable, but also is not good for the engine. As a method of preventing the shock that occurs when the hydraulic clutch is engaged, there is a method that uses a slow-fitting valve that applies an interpressure valve structure, but in this case, the pressure is lower than when the hydraulic circuit is opened in the forward and reverse cylinders. Therefore, there is a problem that the fitting time is too long.

Another method used is to prevent shock during insertion by performing insertion in the trolling position, but this also has the same problem as above in that it takes too much time to insert. The disadvantage is that it is difficult to operate manually.

In order to solve such problems, the present applicant has filed an invention for a hydraulic clutch insertion shock prevention device (Japanese Patent Application No. 58-64433, Japanese Patent Application Laid-open No. 59-190519).

As shown in the claims and drawings (number 18 in Figure 1), this invention electrically switches the hydraulic clutch, so for example, if the electric circuit breaks down for some reason and the clutch does not function properly. When this happens, there is a problem in that the clutch can no longer be switched.

Another problem with clutches is that when the engine speed is relatively low, torque fluctuations in the propeller shaft and the engine's power transmission shaft can cause resonance noise in the reduction gear, causing a rattling noise. This sound is usually called a rattling sound, and it makes the ride of ships uncomfortable, and in the case of fishing boats, the rattling sound causes fish to run away, which has a negative impact on fishing.

[Purpose of the invention]

The present invention has been made in view of the above-mentioned circumstances, and not only prevents the shock when the hydraulic clutch is fitted, shortens the fitting time, but also prevents rattling noise when the engine speed is relatively low. We provide a control system that can maximize the rotational speed transmission rate from the engine to the propeller and control the propeller rotational speed to an extremely low value, and is resistant to failures and can be operated manually even in the unlikely event of a failure. The purpose is to enable clutch switching at

[Structure of the invention]

To achieve this objective, the present invention is constructed as shown in the functional block diagram of FIG. That is, a hydraulic clutch C is interposed between an engine a and a propeller b, and an electric drive device d increases or decreases the hydraulic pressure supplied to the hydraulic clutch C.
Clutch switching means e for mechanically switching the hydraulic clutch C; switching detection means f for detecting on/off of the clutch C;
A means q for setting the output rotation speed of the engine a, a means g for detecting the engine rotation speed, a means for setting the rotation speed of the propeller b, a means i for detecting the propeller rotation speed, and the electric drive device d. When clutch off is detected by this switching detection means j, the electric drive device d is actuated to adjust the oil pressure of the hydraulic clutch C until the set propeller rotation speed reaches the maximum. When the off-time oil pressure is at a low level, the off-time oil pressure is set to a low level, and when it is not, the off-time oil pressure is adjusted to a high level. After a predetermined period of time, the hydraulic pressure applied to the clutch C is temporarily set to a first hydraulic pressure at a low level, and then the two hydraulic pressures are set to a second hydraulic pressure that maintains a predetermined power transmission.
When transmitting engine rotation to the propeller in an emergency,
When the first oil pressure is set to a higher level than the normal first oil pressure, the set rotation speed of the engine is at a relatively low level, and rattling noise is to be prevented, the second oil pressure is set to:
The first oil pressure is at a relatively low level that is sufficient to maximize the rotational transmission rate from engine a to propeller b, and the first oil pressure when the propeller set rotation speed is at an extremely low level is the same as the normal oil pressure. The second oil pressure is set to a lower level than the first oil pressure, and the second oil pressure is used to control the oil pressure of the clutch C by operating the electric drive device d so that the rotation transmission rate from the engine a to the propeller b is below the maximum value. an on-time pressure regulating means n that once sets the pressure to the first hydraulic pressure and then regulates the pressure to the second hydraulic pressure;
This second rainbow is maintained until it is detected that the clutch C is turned off, and during this maintenance period, the rotation transmission rate from the engine a to the propeller b does not reach the target maximum value. When it is detected that the propeller rotation speed has not been reached, the oil pressure is adjusted to a high oil pressure and then lowered to the second oil pressure, which is a relatively low level sufficient to maximize the transmission rate. A hydraulic clutch control device for a ship, characterized in that it is equipped with a maintenance means p.

That is, the control during switching of the hydraulic clutch according to the present invention is such that when clutch off is detected, the off oil pressure is set corresponding to each operation mode, and when on is detected, the hydraulic clutch is controlled for a predetermined time T.
Basically, after a time period of 1, the first hydraulic pressure is set to a low level, and then a second hydraulic pressure corresponding to a predetermined operation mode is applied to the hydraulic clutch.

The operation mode is Tsuho's ° operation mode, an emergency mode that changes the rotation of the propeller urgently, and a mode that sails at a relatively low speed and without making rattling noises,
Furthermore, the term "at an extremely low propeller rotation speed" means, for example, when trolling fishing is carried out. Furthermore, the above-mentioned emergency situation includes operational purposes such as sudden stopping and throwing fishing nets into the sea.

〔Example〕

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention implemented on a diesel engine mounted on a trawler will be described in detail below with reference to the drawings.

FIG. 2 shows a hydraulic clutch control device for diesel engine E. In the figure, 1 is a remote control handle, and this remote control handle 1 includes a clutch switching handle 2.
and a regulator handle 3. The clutch switching handle 2 turns the hydraulic clutch on and off by shifting forward and backward, and when it is turned on, there are two modes: forward movement and backward movement. A push-pull cable 4 is attached to this clutch switching handle 2, and the tip of this push-pull cable 4 is fixed to the tip of a switching lever 6 of a clutch actuator 5.

FIG. 3 shows the clutch actuator 5, and the switching lever 6 is in the neutral position shown by the solid line in FIG.
Among the positions indicated by the chain lines, the upper one is forward movement, and the lower one is backward movement. A rotary portion 8 shown in FIG. 4 is attached to the shaft 7 of the switching lever 6, and the rotary portion 8 is rotatably supported within the main body of the clutch actuator 5. This rotary part 8 is provided with clutch oil passages 9,10 which are arranged at an angle of 90 degrees to each other, and a sensor oil passage 11 is arranged which is arranged at a position that is equiangular to the clutch oil passages 9,10. These oil channels 9, 10, 11 communicate in the center of the rotary part 8.

For this rotary part 8, the clutch actuator 5
On the main body side, there is a clutch operation oil passage 12 in the left direction, a forward clutch oil passage 13 in the upper direction, a reverse clutch oil passage 14 in the lower direction, and a forward movement sensor oil passage 15 parallel to each other in the right direction.
and a reverse sensor oil passage 16 is narrowed. Above oil path 1
2 is supplied with clutch hydraulic oil whose original oil pressure has been reduced from a pressure reducing valve 28 to be described later, and this pressurized oil is supplied to the forward clutch oil path 13 or the reverse clutch oil path 14 via the clutch oil path 9.10. In addition, the oil is supplied to the forward sensor oil path 15 or the reverse sensor 16 via the sensor oil path 11.

The forward clutch oil passage 13 and the reverse oil passage 14 communicate with the forward cylinder 17 and the reverse cylinder 18 of the hydraulic clutch, respectively, and forward clutch insertion sensors 19 are provided at the ends of the forward sensor oil passage 15 and the reverse sensor oil passage 16, respectively. , a reverse clutch insertion sensor 20 is provided.

As shown in FIG. 4, both sensors 19 and 20 are equipped with a piston valve 210 and a valve spring 23.
By moving the piston valve 21 and the rod 22 against the pressure 3, the engagement of the forward clutch or the reverse clutch is detected, and this detection signal is sent to the control unit 24 as a forward engagement signal or a reverse engagement signal. Clutch-off state is when neither signal for switching the hydraulic clutch is given. This clutch actuator 5 and the clutch switching handle 2 constitute clutch switching means f in FIG. 1.

When the clutch switching handle 2 is switched forward, the switching lever 6 of the clutch actuator 5 is rotated to the upper position in FIG. 3, and the rotary part 8 is connected to the oil passage as shown in FIG. state, the pressurized oil flows through the operating hydraulic oil path 12, the clutch oil path 9, and the lO1 forward clutch oil path 1.
3 to the forward movement cylinder 17, and the hydraulic clutch is engaged in the forward movement state.

As shown in FIG. 3, the clutch actuator 5 includes:
A motor 25 and a control shaft position sensor 26 are provided, the motor 25 is driven by a drive signal from the control unit 24, and a control shaft 29 is provided on the rotational drive shaft of the motor 25 via a gear mechanism 27 so as to be able to move back and forth. The pressure reducing valve 28 is operated by the back and forth movement of the control shaft 29 to adjust the oil pressure. The base end of the control shaft 29 is obliquely cut out to form a cam surface 29a, and the control shaft position sensor 26, which is a differential transformer, is attached to the cam surface 29a.
A detection guide bin 26a at the tip of the movable core moves up and down together with the movable core, and the position of the movable core is detected by the coil of the control shaft position sensor 26, which is an actuating transformer, and is used as a position detection signal for the control shaft 29 for the control described above. Section 24.

As understood from the above explanation, the position of the control shaft 29 directly corresponds to the oil pressure applied to the clutch, and therefore the oil pressure of the hydraulic clutch is detected based on the above signal. With the above, the motor 25
corresponds to the electric drive device d in FIG. 1, and the control shaft position sensor 26 also corresponds to the oil pressure detection means j in FIG.

The shift operation of the trolling handle 31 provided on the other remote control handle 3o is also connected to the lever 33a of the trolling lever position sensor 33 through the push-pull cable 32, where it is electrically detected, and the control unit 24 controls the clutch actuator 5. motor 2
5 is activated to achieve a half-clutch condition for trolling.

Further, the rotational power of the engine E is transmitted to the propeller shaft 35 via a hydraulic clutch (not shown) housed in the clutch 34. An engine rotation sensor 36 consisting of an electromagnetic pickup or the like is provided opposite to the propeller shaft 35.

An engine rotation sensor 3 comprising an electromagnetic pickup or the like is attached to a rotating shaft 38 that is driven by a crankshaft (not shown) of the engine E and drives a fuel injection pump 37.
9 are provided opposite to each other, and the detection signal of this sensor 39 is sent to the control unit 24.
is given to detect the rotational speed of the engine E.

The control unit 24 controls the CP'U40. ROM41, RAM42
The CPU 40 performs various control processes based on programs stored in the ROM 41, and the resulting data and the like are stored in the RAM 42. When this control section 24 receives a fitting signal from the clutch fitting sensor 19.20, the control section 24 generates a control shaft position detection signal indicating the current oil pressure value from the control shaft position sensor 26.
After checking the oil pressure value, drive the motor 25 to increase or decrease the oil pressure.

On the other hand, the mode switch 43 is a switch for switching to each mode: neutral mode (N) used for normal boat maneuvering, emergency mode (H) for sudden starts, sudden stops, etc., and rattle noise prevention mode (L). Mode switch 43
The on signal is given to the control section 24.

In this embodiment, as described above, the forward and reverse clutch engagement sensors 19 and 20 are provided, but by making them operate simultaneously, detection of the clutch engagement signal can be made more reliable.

By doing so, the risk of malfunction can be reliably eliminated.

Next, the operation of this embodiment will be described with reference to the flowcharts shown in FIGS. 5 to 8. In the above flowchart, Ne is the engine E rotation speed detection value, Np is the propeller rotation speed detection value, Nps is the propeller rotation speed setting value, P is the oil pressure value at clutch off, and P2 is the clutch in normal mode. P2H is the first oil pressure when the clutch is on in normal mode, P2T is the first oil pressure when the clutch is on in trolling mode, P5 is the second oil pressure when the clutch is on in normal and emergency modes. , Pr5t represents the second minimum oil pressure value in the trolling mode, T1 represents the waiting time when the clutch is off, and T2 represents the waiting time when changing from the first to the second oil pressure when the clutch is on.

Now, if the clutch switching handle 2 is in the OFF state,
Since the signal from the clutch insertion sensor 19, 20 is not given, the control unit 24 detects the clutch off in step (3) and executes the program P shown in FIG. 6 to reduce the source pressure to the clutch-off hydraulic pressure. do. That is, in step P1, it is determined whether the engine rotational speed is a rotational speed suitable for cruising (in this embodiment, 1500 rpm or more). yes
Then, in step P2, the control unit 24 drives the motor 25 to maintain the off-state oil pressure P1 (this oil pressure is appropriately 15 kg/cn1 or more for the engine E of a normal fishing boat, etc., and in this embodiment, it is 20 kg/cnl). ), and if no, it is determined whether or not to troll (step P3).

In step P3, if it is detected that the engine rotation speed exceeds the discrimination reference value (220 rpm in this example) and no trolling is detected, the pressure is regulated to P in the same way as above, and if trolling is detected, the process is stopped in step P4. It is determined whether or not the engine is running (30 rpm+ or less in this embodiment), and if the engine is not stopped, the pressure is regulated to an off-state oil pressure P2T in which power is transmitted while the clutch is slipping. In this case, the motor 10 of the clutch actuator 5 is driven back and forth to pulsate the oil pressure, and control can be achieved by a power transmission method using intermittent drive. Each of the above steps corresponds to the off-time pressure regulating means k in FIG. Then return to step ■.

Next, when the clutch switching handle 2 is switched to the forward direction, the forward clutch engagement sensor 19 gives an engagement signal, so the control section 24 detects the clutch on in step (2) and activates the clutch on pressure regulating means n in FIG. is executed.

First, the control unit 24 waits for operation for a time T1 in step Q1.

Due to the above-mentioned time T1, pressurized oil with high oil pressure is forcefully sent into the hydraulic clutch 31, and the fitting time is shortened accordingly. If this continues, clutch b will be connected and a clutch engagement shock will occur, so immediately after that, the oil pressure is sharply reduced to alleviate this. This is the same even when moving backwards.

Next, in step Q2, it is again determined that the engine rotational speed is a rotational speed suitable for cruising (in this embodiment, 1500 rpm or more). If yes, the control unit 24 detects the mode selected by the mode selection switch 43 in step Q3.

Now, in step Q3, when it is detected that the mode switch 38 is turned on and set to the emergency mode (H), the control section 24 drives the motor 25 to set the second hydraulic pressure when the hydraulic clutch is turned on. It is lowered to P2H (step Q4). In this embodiment, this second oil pressure is approximately 2.
8kg/al! and a relatively high low pressure level.

Next, the control unit 24 waits for a time T2 in step Q5, and then increases the oil pressure to the second on-time oil pressure P5 in step Q6, and thereafter maintains this high pressure P1 until the next time the clutch is turned off (step Q6.7).

Each of the above steps corresponds to the on-time pressure regulating means n and the oil pressure maintaining means p in an emergency. The state of control during this emergency will be explained with reference to time charts shown in FIGS. 9-1 to 9-3.

The vertical axis in Fig. 9-1 indicates the detected propeller rotation speed, and the vertical axis in Fig. 9-2 indicates each oil pressure applied to the clutch.
9-3 shows a fitted state of the clutch of FIG. 9-3. In the diagram, each pole line in an emergency is indicated by an H pole line. Each numerical value in the figure represents the above-mentioned value. Further, the dotted line indicates a shock state caused by a conventional hydraulic clutch.

By comparing the two in FIG. 9-1, the emergency shock of this embodiment is also observed in this embodiment, but as shown in the N curve, the shock is greater than that of the conventional case. It's much more soothing. In addition, what is shown on the right side of FIG. 9-1 shows switching from forward movement to reverse movement. That is, even in operations such as throwing fishing nets into the sea, the shock is felt by the worker more softly than before.

Next, in step Q3, when it is detected that the mode switch 43 is in the normal mode (N) or rattle prevention mode (L), the control section 24 controls the on-time first oil pressure P2.
(Step Q9). In this embodiment, this oil pressure value is selected to be approximately 2 kg/cI11, which is lower than that in the emergency mode, and the clutch engagement time is longer than in an emergency, thereby further softening the shock.

Next, the control unit 24 controls the drive of the motor 25 in step Q.
After waiting for time T2 in IO, it is determined in step Qll whether the selected mode is normal mode (N) or rattle prevention mode (L), and when normal mode (N) is detected, , in step Q6, the pressure is regulated to the second oil pressure P5 when the clutch is turned on, as described above, and this oil pressure is maintained until the next time the clutch is disengaged.

The time chart of the propeller rotation speed, the oil pressure sent to the hydraulic clutch, and the clutch engagement state at this time is shown in the ninth section above.
It is shown as the north pole line in Figure-1 to Figure 9-3. In addition, the N curve of the cloth in the figure is a diagram when changing from forward movement to reverse movement. In either case, unlike the conventional case (dotted line), there is no shock and the clutch switching operation can be performed smoothly.

In addition, in step Qll above, the rattle prevention mode (
If it is detected that the engine 15
Calculate the second hydraulic pressure P3 at the time of ON that maximizes the transmission rate from to the propeller 17 to "1", and as shown by the two-dot chain line in Figure 9-2, the hydraulic pressure P3 is lower than the hydraulic pressure P5 above. raise it to When the engine speed is low, propeller shaft 35
The load on the hydraulic clutch 16 is also small, so the hydraulic pressure of the hydraulic clutch 16 can be lowered while keeping the transmission ratio at the maximum "1".
The oil pressure P3 is calculated as this limit oil pressure.

In this way, the rattling noise that occurs when the rotational speed of the engine 15 is low and the oil pressure of the hydraulic clutch 16 is high can be prevented from occurring. Through each of the above steps, the pressure regulating means n when the clutch is on is executed.

Then, the control unit 24 maintains the oil pressure level of P3 until it is detected in step Q13 that the clutch is off. This step corresponds to the oil pressure maintaining means p in FIG.

When the clutch is turned off, this is detected in step Q13, and the program P shown in FIG. 6 is executed again, and the pressure is regulated to the off-time oil pressure of P.

When the control unit 24 detects in step Q8 of FIG. 7 that the trolling handle 31 has been shifted and a low level set propeller rotation speed has been selected, program T is executed.

That is, the control unit 24 controls the motor 2 in step T1.
In this embodiment, P2T is also adopted as the second oil pressure when the clutch is on, and the standby time T2 is omitted.

In step T2, the control unit 24 sets the set propeller rotation speed to a low level (30 rpm or less in the case of this embodiment).
It is determined whether or not the rotation of the propeller is stopped.
3) If yes, control is performed by feedback control using propeller rotation speeds N and p to match the set propeller rotation speed.

Further, when it is detected in step T3 that the rotation of the propeller has stopped, the propeller is in a completely stretched state, so the control section 24 drives the motor 25 to temporarily increase the oil pressure. (step T6), and in step T7 it is determined that the propeller rotation matches the set rotation speed, and this high pressure is maintained until the rotation speed matches. If a match is detected, the initial oil pressure value is changed in step T8. The hydraulic pressure is returned to P2T, and feedback control based on the propeller rotation speed in step T6 is executed. This situation is shown by trolling curve A in Figure 9-1.

When this feedback control is performed using the intermittent drive, the rotation speed can be controlled by adjusting the pulsation period of the oil pressure.

Further, when the control unit 24 detects that the set propeller rotation speed is 3 Orpm or less in the above step T2, the above-mentioned on-time second hydraulic pressure is set to the lowest pressure Pr5t in step T9.
The pressure is released to 1, and the ship essentially stops. The situation at this time is shown by curve B in FIG. 9-1.

Through each of the above steps, the pressure regulating means n when the clutch is turned on in the trolling mode is executed.

Then, in step T5, the control unit 24 determines whether the set propeller rotation speed is in the trolling mode, that is, in this embodiment, 220 rpm+ or more, and when it is detected that the set propeller rotation speed is 220 rpm or less to continue trolling. repeats each step above. Each of these steps corresponds to the oil pressure maintaining means p in FIG.

The present invention may be practiced without providing the standby time T2 when shifting from the first oil pressure to the second oil pressure during off-time in this embodiment.

Furthermore, although the clutch operating oil pressure coming out of the pressure reducing valve of the clutch actuator may be detected using a normal oil pressure measurement method, it is better to detect it by varying the position of the control shaft of the actuator as in this embodiment. Response is fast and control operations can be executed more accurately.

〔Effect of the invention〕

As described above, the present invention mechanically switches the hydraulic clutch, and when the clutch is off, the clutch oil pressure is set to the high-pressure off oil pressure, and when it is detected that the clutch is on, the clutch is switched on for a short period of time. After waiting and pressurizing oil into the hydraulic clutch, the clutch oil pressure is once lowered to the second oil pressure when turned on, and then the pressure is regulated to the second oil pressure that matches the selected operation mode. Since the oil pressure is maintained until the clutch is released, the following effects can be achieved.

(1) When the clutch is on, pressurized oil is sent out forcefully by the off-state oil pressure, shortening the engagement time, and immediately after that, the oil pressure is lowered to the first on-state oil pressure, and then the selected mode is changed. Since the suitable second hydraulic pressure is applied when the clutch is turned on, the shock when the clutch is engaged is also alleviated, and the feeling of maneuvering and the 4° ride comfort in the boat can be improved.

(2) By setting the second hydraulic pressure to a high level, it is possible to make the shock much smaller than before even when performing emergency maneuvers such as throwing a fishing net into the sea or making a sudden start. possible.

(3) Regarding the rattling noise that occurs when the engine speed is relatively low and the oil pressure of the hydraulic clutch is large, the second oil pressure when turned on is low enough to make the rotation transmission rate from the engine to the propeller rlJ. By using hydraulic pressure, it is possible to prevent the rattling noise from occurring, and as a result, it is possible to prevent the ship from becoming uncomfortable to ride on, and in the case of a fishing boat, to prevent fish from running away due to the rattling sound.

(4) Furthermore, since the clutch switching means is mechanically configured, electrically configured devices such as those that are switched using electromagnetic valves will not malfunction due to salt water, etc., making it safer. It is possible to perform smooth sailing.

[Brief explanation of drawings]

FIG. 1 is a functional block diagram showing the configuration of the present invention, FIG. 2 is an overall configuration diagram of a control device according to one embodiment, FIG. 3 is an overall overview of the clutch actuator 5, and FIG. 4 is a main part of the clutch actuator. The cross-sectional views, FIGS. 5 to 8 are flowcharts of clutch oil pressure processing, and FIGS. 9-1 to 9-3 are time charts for each mode. 2...Clutch switching handle, 3...Regulator handle, 5...Clutch actuator, 6...
Switching lever, 8... Rotary part, 12... Supply pressure oil path, 17... Forward cylinder, 18... Reverse cylinder, 19... Forward insertion sensor, 20... Reverse insertion Sensor, 24... Control unit, 25... Motor, 26
...Control shaft position sensor, 28...Control shaft, 31...Trohill handle, 3
3... Troll handle sensor, 34... Hydraulic clutch case, 35... Propeller 7 axes, 36... Propeller rotation sensor, 38... Mode changeover switch, 39...
...Engine rotation sensor, E...Engine.

Claims (1)

[Claims] In a marine hydraulic clutch that has a hydraulic clutch interposed between an engine and a propeller and an electric drive device that increases or decreases the pressure supplied to the hydraulic clutch, clutch switching is used to mechanically switch on/off the hydraulic clutch c. switching detection means for detecting on/off of the clutch c; means for setting the output rotation speed of the engine; means for detecting the engine rotation speed; means for setting the rotation speed of the propeller; propeller rotation speed detection means for detecting the target rotation speed by the setting means; oil pressure detection means for detecting oil pressure when operating the electric drive device; and when clutch off is detected by the switching detection means, the electric drive device an off-time pressure regulating means that operates to adjust the hydraulic pressure of the hydraulic clutch to a low level of off-time hydraulic pressure when the set propeller rotation speed is at an extremely low level, and to a high level of off-time hydraulic pressure otherwise; After a predetermined period of time when the switching detection means detects switching to clutch-on, the hydraulic pressure applied to the clutch is temporarily set to a first hydraulic pressure at a low level, and then the two hydraulic pressures are set to a second hydraulic pressure that maintains power transmission. When the rotation of the engine is urgently transmitted to the propeller, the first oil pressure is set to a higher level than the normal first oil pressure, so that the set rotation speed of the engine is at a relatively low level and the generation of rattling noise is prevented. In this case, the second oil pressure is a relatively low level oil pressure sufficient to maximize the rotation transmission rate from the engine to the propeller, and the second oil pressure is a relatively low level oil pressure sufficient to maximize the rotation transmission rate from the engine to the propeller, and the second oil pressure is a relatively low level oil pressure that is sufficient to maximize the rotation transmission rate from the engine to the propeller. The hydraulic pressure is at a lower level than the normal first hydraulic pressure, and the second hydraulic pressure is set by operating the electric drive device to increase the hydraulic pressure so that the rotation transmission rate from the engine to the propeller is below the maximum value. on-time pressure regulating means for once setting the hydraulic pressure of the clutch to the first hydraulic pressure and then regulating the pressure to the second hydraulic pressure; and maintaining the second hydraulic pressure until it is detected that the clutch is turned off; During the maintenance period, if it is detected that the above-mentioned rotation transmission rate has not reached the target maximum value or the set propeller rotation speed, the oil pressure is set to a high oil pressure and then the above-mentioned transmission rate is set to the maximum. A control device for a hydraulic clutch for a marine vessel, characterized in that the control device comprises a hydraulic pressure maintaining means for reducing the second hydraulic pressure to a relatively low level sufficient to maintain the second hydraulic pressure.