JPH09250564A - Hydraulic control device for clutch of vessel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To adapt an identical vessel decelerating reversing gear to a mechanical and an electronic control type system by operating a low speed sailing lever operating a low speed valve with an electronic control system through an actuator while a conventional forward/reverse selector valve and the low speed valve, are used as usual. SOLUTION: In a vessel decelerating reversing gear which is so constituted as to be equipped with a low speed valve V1 and a low speed sailing lever L1 operating the low speed valve V1, the angle of the low speed sailing lever L1 of the low speed valve V1 is controlled based on the revolution speed of an engine mounted as an input signal. In the case such as control for the enlargement of a trawling range as a pattern at the time of raising engine revolution, and a reduction in engagement shock caused by making the lever speed slower just before an engaging point and the like, hydraulic control is thereby executed in response to the angle of the low speed sailing lever L1 of the low speed valve V1. Besides, on condition that a neutral switch can be turned ON/OFF, the angle of the low speed sailing lever L1 of the low speed valve V1 is controlled, so that responsiveness is thereby improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention utilizes a low speed valve provided in a marine speed reducer / reverser for shifting the rotation of an engine to forward / reverse rotation and connecting / disconnecting power in a small boat such as a fishing boat.
It is possible to retrofit various electronic controls.

[0002]

2. Description of the Related Art Conventionally, as a trolling control device for a speed reducer / reverser for a ship, a technique as disclosed in Japanese Patent Laid-Open No. 4-31194 has been known.

[0003]

As disclosed in the above-mentioned prior art, a technique for performing muffling control, acceleration control, etc. by using an electromagnetic proportional control valve or the like is known. However, an electronic control mechanism that uses a solenoid proportional valve or the like has a high cost in order to be able to match an optimal control system to a ship body that differs depending on the shipyard,
It was necessary to incorporate some control software, and it was impossible to reduce the number of parts. In addition, since the electromagnetic proportional control valve and the like originally aim to eliminate the control lever and the like, the conventional mechanical lever operation method and the electronic lever-less operation method cannot coexist, and the electronic In the case of a controlled marine speed reducer / reverse machine, it was necessary to assemble with completely different and different parts. In the present invention, the conventional forward / reverse switching valve and the low speed valve are used as they are, and the low speed navigation lever for operating the low speed valve can be operated by the electronic control system via the actuator. The same marine speed reducer / reverse gear can be used. Further, since the actuator can be operated with respect to the low speed navigation lever L1 of the low speed valve V1 and the operation amount of the actuator is controlled, even when the ship shape, the weight of the hull or the like changes for each shipyard. By making the final adjustments at the final navigation test at sea, etc., it is possible to easily adjust to the optimum control system that matches different hulls. As a result, by using the conventional marine speed reduction / reversing machine equipped with the forward / reverse switching valve V2 and the low speed valve V1 as it is, the cost is low and it is possible to adjust and match in the case of a hull of a different ship type. A hydraulic control method for a marine clutch is provided. As described above, according to the present invention, by simply connecting the electronic control system to the low speed navigation lever L1 via the remote control cable 3, the low speed valve which has been conventionally provided is used to muffle the sound or impact the clutch. In addition, the trolling range is expanded and the acceleration performance when departing from the fishing port is improved.

[0004]

Means for solving the problems of the present invention will be described below. In claim 1, the forward clutch F is provided from the hydraulic pump P via the forward / reverse switching valve V2.
C and a reverse clutch RC have a hydraulic circuit for selectively supplying hydraulic oil for clutch engagement, and a low speed valve V1 for controlling hydraulic oil pressure to the hydraulic circuit and a low speed navigation lever L1 for operating the low speed valve V1. In the marine deceleration / reverse gear, the low-speed navigation lever L1 of the low-speed valve V1 is configured to be operable by the actuator 4, and the angle of the low-speed navigation lever L1 of the low-speed valve V1 is set by using the engine speed of the mounted engine as an input signal. Is controlled to control the hydraulic pressure pattern corresponding to the engine speed.

According to a second aspect of the present invention, there is provided a hydraulic circuit for selectively supplying hydraulic oil for clutch engagement from the hydraulic pump P to the forward clutch FC and the reverse clutch RC via the forward / reverse switching valve V2. In a marine speed reduction / reversing machine provided with a low speed valve V1 for controlling hydraulic oil pressure in the circuit and a low speed navigation lever L1 for operating the low speed valve V1, a low speed navigation lever L1 of the low speed valve V1 is operable by an actuator 4. , Corresponding to the angle of the low speed navigation lever L1 of the low speed valve V1, such as control of the pattern at the time of rotation start-up for expanding the trolling range and reduction of impact fitting by slowing the lever speed before the fitting point. , Hydraulic control is performed.

According to another aspect of the present invention, there is provided a hydraulic circuit for selectively supplying the clutch engaging hydraulic oil from the hydraulic pump P to the forward clutch FC and the reverse clutch RC via the forward / reverse switching valve V2. In a marine speed reduction / reversing machine provided with a low speed valve V1 for controlling hydraulic oil pressure in the circuit and a low speed navigation lever L1 for operating the low speed valve V1, a low speed navigation lever L1 of the low speed valve V1 is operable by an actuator 4. , Forward / reverse switching lever L for operating the forward / backward switching valve V2
The ON / OFF state of the neutral switch for detecting the neutral position 2 is used as an input condition to control the angle of the low speed navigation lever L1 of the low speed valve V1 to improve the responsiveness.

In the fourth aspect, a plurality or all of the hydraulic control patterns of the first or second aspect are controlled.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Next, embodiments of the present invention will be described. FIG. 1 is a drawing showing a marine speed reducer / reverse machine, a controller 6, an actuator 4 and the like showing a hydraulic control method for a marine clutch of the present invention, and FIG. 2 is a hydraulic circuit and a control block diagram showing a hydraulic control method for a marine clutch of the present invention. 3 is a drawing showing the relationship between the lever angle of the low speed navigation lever L1 and propeller rotation, engine rotation, and clutch hydraulic pressure in the hydraulic control method for a marine clutch of the present invention, and FIG. 4 is the lever angle of the low speed navigation lever L1 of the present invention. And drawing showing the rotation of the propeller, Fig. 5
Is a flow chart drawing of "fitting shock reduction function", FIG. 6 is a flow chart drawing of "silence valve function", and FIG. 7 is a flow chart drawing of "protection function during trolling",
FIG. 8 is a flow chart drawing of the “low speed hysteresis avoidance function”, FIG. 9 is a flow chart drawing of the “fine slip area improving function”, FIG. 10 is a flow chart drawing of the “responsiveness improving function”, and FIG. 11 is a “responsiveness improving function”. ] FIG. 12 is a view showing an embodiment of another flow chart of FIG.
It is drawing which shows the relationship between S and the forward / backward switching lever L2.

Referring to FIG. 1, the construction of a handy remote controller H, a controller 6, an actuator 4, a remote control cable 3, a low speed valve operating lever 2 and the like attached to a marine speed reducer / reverse gear will be described. Two hydraulic clutches, a forward clutch FC and a reverse clutch RC, are arranged inside the marine speed reduction / reverse gear, and the rotation from the engine is switched to forward / neutral / reverse by the marine speed reduction / reverse gear to propeller shaft. Communicate to. It is the handy remote controller H that remotely controls the hydraulic control system of the marine clutch.
An alarm lamp A is attached to. The controller 6 is remotely controlled by the handy remote controller H. A control signal from the controller 6 reaches the actuator 4, and the actuator 4 operates the remote control cable 3 to expand and contract.

The remote control cable 3 is connected to the low speed valve operating lever 2. A low speed navigation lever L1 of the low speed valve V1 is connected from the low speed valve operating lever 2 to a remote control cable 3.
Are linked to operate. An output shaft rotation speed sensor S1 and an engine rotation speed sensor S2 are also arranged on the engine side. Signals indicating the rotational speeds of the output shaft rotational speed sensor S1 and the engine rotational speed sensor S2 and the connection state of the hydraulic clutch are transmitted. Based on these signals, "low speed hysteresis avoidance function", "protection function during trolling", "silence valve function", "insertion shock reduction function", "improvement function of minute slip range", and "responsiveness improvement function" Is controlled by the handy remote controller H and the controller 6, the actuator 4 is operated based on a signal from the controller 6, and the low speed valve operating lever 2 and the low speed navigation lever L1 are operated via the remote control cable 3. It is a thing.

Referring to FIG. 2, a hydraulic circuit constituting a hydraulic control method for a marine clutch of the present invention and a control block diagram will be described. The hydraulic oil in the hydraulic oil tank T is sucked by the hydraulic pump P and discharged as pressure oil. The pressure oil from the hydraulic pump P is branched into the circuit of the loose fitting valve V6 and the hydraulic pressure adjusting valve V5. When the forward / reverse switching valve V2 is neutral, the loose fitting inlet valve V6 lowers the pressure in the back chamber so that the urging force of the urging spring does not act on the operating hydraulic pressure adjusting valve V5. Is the hydraulic oil pressure regulator V5 to the lubricating oil cooler LC
And the lubricating oil pressure adjusting valve V7.

Then, when the forward / reverse switching valve V2 is switched to forward or reverse, pressure oil is gradually supplied to the back chamber of the loose fitting inlet valve V6 through the throttle, and gradually relaxes from the low pressure state. The pressure in the back chamber of the fitting valve V6 rises, and the pressure of the biasing spring of the loose fitting valve V6 is switched to a direction in which leakage of pressure oil from the operating oil pressure adjusting valve V5 is reduced, and the pressure of the reverse clutch RC or the forward clutch FC is changed. Gradually increase the forward clutch F
This is a mechanism for preventing impact joining by slowly fitting C and the reverse clutch RC. The pressure oil leaking from the operating oil pressure adjusting valve V5 passes through the lubricating oil cooler LC and is applied with a constant low pressure by the lubricating oil pressure adjusting valve V7, and then the forward clutch F from the lubricating oil circuit.
It is supplied for lubrication of C and the clutch disc of the reverse clutch RC.

Next, the pressure oil from the hydraulic pump P is supplied to the low speed valve V.
Pass 1 circuit. The low speed valve V1 is the hydraulic pressure adjusting valve V3
When the low speed navigation lever L1 is operated, the piston 5 of the low speed valve V1 is configured to open / close the hydraulic pressure adjusting valve V3 via the biasing spring 8. As a result, the operator operates the hydraulic pressure adjusting valve V3 in the closing direction by the low speed navigation lever L1, and the forward / reverse switching valve V3.
By squeezing the pressure oil from 2 to the clutch, the hydraulic pressure in the reverse clutch RC or the forward clutch FC is lowered, and the clutch disc is slipped to obtain the low speed rotation of the propeller.

The pressure reducing valve mechanism composed of the low speed valve V1 and the hydraulic pressure adjusting valve V3 has been conventionally provided.
Conventionally, the low speed navigation lever L1 is configured to be operated by an operator directly or remotely. According to the present invention, the low speed navigation lever L1 is automatically operated by the handy remote controller H, the controller 6, the actuator 4 and the remote control cable 3.

Next, the "fitting shock reducing function" during trolling by electronic control will be described with reference to FIGS. 3, 4, and 5. An electronically controlled system that reduces the impact shock caused by a sudden change in hydraulic pressure in the vicinity of the engagement by automatically adjusting the operation speed of the low speed navigation lever L1 during trolling with the pressure reducing valve of the method in which the low speed navigation lever L1 is operated by the operator. is there. Conventionally, in order to avoid a fitting shock, the fitting lever position is empirically grasped, and it is avoided by reducing the speed in the vicinity of the lever angle. However, when the engine speed is changed, the fitting position also changes, so it was necessary to find the lever position.

In the present invention, the engine speed is detected by the engine speed sensor S2, and the propeller speed is detected by the output shaft speed sensor S1 and transmitted to the controller 6. The flowchart of the control of the "fitting shock reducing function" is as shown in FIG. First, the lever angle La of the low speed navigation lever L1 is La = L
It is determined whether or not it is a2, and it is determined whether or not the rotation speed is close to the insertion point. Also, it is determined whether or not the rotation is in the startup state. If these are NO, it is determined that the normal trolling operation is performed, and the "fitting shock reducing function" is not performed. Then, in the case of YES where it is determined that it is the fitting point at the time of starting the rotation, the fitting point which is different depending on the engine speed is automatically calculated by the controller 6, and the actuator 4 is placed before the engine speed.
The motor rotation of is reduced by adjusting the current value, and the operation speed of the low speed navigation lever L1 is reduced. The speed of lever operation before the insertion point is reduced to reduce insertion shock.

Next, the "silence valve function" according to the present invention will be described with reference to the flowchart of FIG. In a marine speed reducer / reverse machine, a "silence valve function", which is a device for taking a rattling noise at a low speed generated at a certain rotational speed due to resonance, is performed by a low speed valve V1 and electronic control.
The conventional "silence valve function" is dealt with by simply lowering the clutch hydraulic oil to a low pressure P1 (Fig. 3) at low engine speed. The muffling valve and the low speed valve have almost the same function, but conventionally, they are provided respectively. In the present invention, the versatility of the electronic control is utilized, and as a part of the control, the low speed valve V1 is arbitrarily operated to have the function of "silence valve function".

In the case of this "silence valve function", first, a judgment for turning on the silence function is made. First, it is determined that the engine speed is equal to or lower than the set speed (Ni1 in FIG. 3), secondly the propeller is in a rotating state, and thirdly, it is not in a trolling state. Above "silence valve function"
When it is determined to be the ON state, the low speed navigation lever L1 is operated so that the operating oil pressure becomes low. When the engine speed exceeds Ni1, the low speed navigation lever L1 is operated to the completely engaged position (angle 0 in FIGS. 3 and 4).

Next, referring to FIG. 7, "protection function when the set input speed during trolling exceeds Ni2 in FIG. 3"
Will be described. This function uses the function of the low-speed valve V1 of the marine reduction / reversing machine to increase the engine speed during trolling, which may cause a sudden seizure of the clutch and a sudden fit when the clutch is completely engaged at the end of trolling. It is a function to prevent the jumping out. When the trolling operation is performed, the clutch may burn if the engine speed increases for some reason. Also, when the clutch is completely engaged, there is a possibility of sudden start. This is dealt with by monitoring the engine speed using electronic control.

In this operation, when the engine speed exceeds Ni2, the trolling operation is invalidated, and the low speed navigation lever L1 is instructed to maintain the completely engaged position. Even if the engine speed is Ni2 or less and trolling is possible, if the engine speed exceeds Ni2 during the trolling operation, the low speed navigation lever L1 is operated to the lowest speed position. Judgment whether it is a trolling operation,
It is determined whether the dial angle of the handy remote controller H is 0 degree or more.

Next, the "low speed hysteresis avoidance function" will be described with reference to FIG. This function is used to measure the hysteresis at the time of rising and falling of the rotation, which occurs due to the difference between the dynamic friction coefficient and the static friction coefficient of the clutch disc when the propeller rotation is low, for example, 80 rotations (No. 1 in FIG. 3) or less. Is controlled so as to be the same as that on the falling side. For this reason, it is determined whether or not the position of the low speed navigation lever L1 is in the hysteresis region, and it is also determined whether or not it is during the rotation start. If it is at the time of rising, the lever return amount is instructed, and in the initial stage, the lever is returned by, for example, 15 degrees to prompt the engagement of the clutch.
At the time of the turn, for example, it is returned by 20 degrees, and when the rotation rises, the low speed navigation lever L1 is returned to the original position, and the operation is made to correspond one-to-one with the time of the fall.

With this configuration, particularly at the time of start-up, even if the hydraulic pressure is set to a certain constant value, the corresponding rotational speed can be set to any rotational speed from 0 to N. It is possible to eliminate the area of uncertainty that occurs due to. Therefore, the oil pressure on the rising side and the oil pressure on the falling side have a one-to-one correspondence with each other, so that control in the low rotation range can be reliably performed.

Next, referring to FIG. 9, the "small slip area improving function" will be described. This "small slip area improvement function" is an automatic control that eliminates the hysteresis at the time of startup and shutdown that occurs in the vicinity of the engagement pressure of the clutch. In this case, the rotation lowering side is made to coincide with the rotation rising side, which is referred to as a "small slip area improving function". In this case as well, the lever is moved after determining that it is at the time of falling and that it is near the clutch engagement position. Initially, for example, 5 in the lever position
Move to the added position and return to the original position. When the rotation changes by, for example, 10 rotations or more, the same operation is repeated again so that the curve on the falling side is substantially matched with the rising side. As a result, the effective range of the trolling can be expanded and the set rotation can be maintained.

Next, the "responsiveness improving function" shown in FIGS. 10 and 11 will be described. This "responsiveness improvement function"
The slow-moving lever L1 is automatically operated from the trolling state or the muffling function state where it is operated to a place other than the fitting position, and the fitting time is shortened. The working hydraulic pressure may be increased to shorten the fitting time, but rattling noise may occur. The present invention is intended to reduce the fitting time by automatically operating the low speed navigation lever L1 as a trolling device without generating rattling noise.

Therefore, in FIG. 10, it is judged whether the engine speed is Ni1 or less and the propeller shaft has started to rotate, not the trolling state,
The low speed navigation lever L1 is operated to a high pressure range, and after the fitting is completed, the lever is returned to the original position to prevent rattling noise.

In FIG. 11, it is judged that the forward / reverse switching lever L2 of the forward / reverse switching valve V2 is for switching from neutral to forward or reverse, and the low speed navigation lever L1 is temporarily moved to the high pressure region.
Is moved and returned to the original position after the insertion, and the generation of rattling noise is avoided. FIG. 12 is a drawing showing the neutral switch NS for determining whether the forward / reverse switching lever L2 of the forward / reverse switching valve V2 is in the neutral position.

[0027]

Since the present invention is configured as described above, it has the following effects. According to a first aspect of the present invention, the marine speed reduction / reversing machine is provided with a low speed valve V1 and a low speed navigation lever L1 for operating the low speed valve V1, and the low speed of the low speed valve V1 is input by using the engine speed of the mounted engine as an input signal. By controlling the angle of the navigation lever L1, there is no need to perform muffling control, acceleration control, etc. by using an electromagnetic proportional control valve or the like as in the prior art, and the structure can be constructed at low cost. Further, as in the past, an electronic control mechanism using a solenoid proportional valve or the like has a high cost and requires some control software in order to realize an optimal control system for a ship that is different depending on the shipyard. It was necessary to incorporate them, and it was impossible to reduce the number of parts. In the case of the system of the present invention, it is possible to easily adapt to different ship types. Also,
Since the electromagnetic proportional control valve etc. was originally intended to eliminate the control lever etc., the conventional mechanical lever operation method and the electronic leverless operation method can not coexist, and the electronic control type separately In the case of a marine speed reducer / reverse gear, it was necessary to assemble it with completely different parts. In the present invention, the conventional forward / reverse switching valve and the low speed valve are used as they are, and the low speed navigation lever for operating the low speed valve can be operated by the electronic control system via the actuator. The same marine speed reducer / reverse gear can be used. Further, since the actuator can be operated with respect to the low speed navigation lever L1 of the low speed valve V1 and the operation amount of the actuator is controlled, even when the ship shape, the weight of the hull or the like changes for each shipyard. By making final adjustments at the final navigation test at sea, etc., it is possible to easily adjust to control systems that match different hulls. As a result, the conventional forward / reverse switching valve V2
By using the marine speed reducer / reverse gear equipped with the low speed valve V1 as it is, it is possible to provide a hydraulic control method for a marine clutch that is low in cost and can be adjusted and matched in the case of a hull of a different ship type. . As described above, according to the present invention, by simply connecting the electronic control system to the low speed navigation lever L1 via the remote control cable 3, the conventional low speed valve can be used to muffle the sound or impact the clutch. In addition, the trolling range can be expanded and the acceleration performance when departing from the fishing port can be improved.

According to the second aspect of the present invention, the low speed traveling of the low speed valve V1 is performed such as controlling the pattern at the time of starting the rotation for expanding the trolling range and reducing impact fitting by slowing the lever speed before the fitting point. Since hydraulic control is performed according to the angle of the lever L1, effective control can be performed with a simple device.

Since the ON / OFF state of the neutral switch for detecting the neutral position of the forward / reverse switching valve V2 is used as an input condition to control the angle of the low-speed navigation lever L1 of the low-speed valve V1, the neutral-to-forward movement is performed. It is possible to speed up the engagement of the clutch at the start of the vehicle and to make a quick departure.

Since a plurality or all of the hydraulic control patterns according to claim 1 or 2 are controlled as in claim 4, the controller 6 and the actuator 4 are provided in the conventional marine speed reducer / reverser with the low speed valve V1. It was possible to use this device to perform all the controls required for a marine speed reducer / reverse gear by simply installing the.

[Brief description of drawings]

FIG. 1 is a view showing a marine speed reducer / reverse machine, a controller 6, an actuator 4, and the like showing a hydraulic control method for a marine clutch according to the present invention.

FIG. 2 is a hydraulic circuit and a control block diagram showing a hydraulic control method for a marine clutch of the present invention.

FIG. 3 is a diagram showing a marine clutch hydraulic control method according to the present invention, wherein a lever angle of a low speed navigation lever L1 and a propeller rotation,
The drawing which shows the relationship between engine rotation and clutch oil pressure.

FIG. 4 is a drawing showing the lever angle and propeller rotation of the low speed navigation lever L1 of the present invention.

FIG. 5 is a flowchart of a “fitting shock reducing function”.

FIG. 6 is a flowchart of a “silence valve function”.

FIG. 7 is a flowchart of a “protection function during trolling”.

FIG. 8 is a flowchart of a “low speed hysteresis avoidance function”.

FIG. 9 is a flow chart drawing of “improvement function of minute slip area”.

FIG. 10 is a flowchart of a “responsiveness improving function”.

FIG. 11 is a diagram showing an example of another flowchart of the “responsiveness improving function”.

FIG. 12 is a view showing a relationship between a neutral switch NS and a forward / reverse switching lever L2.

[Explanation of symbols]

 2 Low speed valve operating lever 3 Remote control cable 4 Actuator 6 Controller FC Forward clutch RC Reverse clutch LC Lubricating oil cooler S Lubricating oil filter V1 Low speed valve V2 Forward / reverse switching valve V5 Actuating oil pressure adjusting valve V6 Slow fitting valve V7 Lubricating oil pressure adjusting valve V9 Pressure regulator S1 Output shaft speed sensor S2 Engine speed sensor H Handy remote control L1 Low speed navigation lever L2 Forward / reverse switching lever NS Neutral switch

Claims (4)

[Claims] 1. A hydraulic circuit for selectively supplying hydraulic oil for clutch engagement from a hydraulic pump P to a forward clutch FC and a reverse clutch RC via a forward / reverse switching valve V2, and the hydraulic oil is supplied to the hydraulic circuit. Low speed valve V1 for controlling pressure and the low speed valve V
In the marine speed reduction / reversing machine provided with the low speed navigation lever L1 for operating 1, the low speed navigation lever L1 of the low speed valve V1 is configured to be operable by the actuator 4, and the low speed valve is provided with the engine speed of the mounted engine as an input signal. A hydraulic control method for a marine clutch, characterized by controlling an angle of a low speed navigation lever L1 of V1 to control a hydraulic pattern corresponding to an engine speed. 2. A hydraulic circuit is provided which selectively supplies hydraulic oil for clutch engagement from a hydraulic pump P to a forward clutch FC and a reverse clutch RC via a forward / reverse switching valve V2, and the hydraulic circuit has hydraulic oil. Low speed valve V1 for controlling pressure and the low speed valve V
In the marine speed reducer / reverse gear provided with the low speed navigation lever L1 for operating 1, the low speed navigation lever L1 of the low speed valve V1 is configured to be operable by the actuator 4, and the pattern of rotation start-up for expanding the trolling range is set. control,
And the low-speed navigation lever L1 of the low-speed valve V1 to reduce impact fitting by slowing the lever speed before the fitting point.
The hydraulic control method for a marine clutch is characterized in that the hydraulic control is performed according to the angle. 3. A hydraulic circuit for selectively supplying hydraulic oil for clutch engagement from a hydraulic pump P to a forward clutch FC and a reverse clutch RC via a forward / reverse switching valve V2, and the hydraulic oil is supplied to the hydraulic circuit. Low speed valve V1 for controlling pressure and the low speed valve V
In the marine speed reducer / reverse gear provided with the low speed navigation lever L1 for operating 1, the low speed navigation lever L1 of the low speed valve V1 is configured to be operable by the actuator 4, and the forward / reverse switching lever L2 for operating the forward / reverse switching valve V2. A hydraulic control method for a marine clutch, characterized in that ON / OFF of a neutral switch for detecting a neutral position is used as an input condition to control an angle of a low speed navigation lever L1 of a low speed valve V1 to improve responsiveness. 4. A hydraulic control method for a marine clutch, wherein a plurality or all of the hydraulic control patterns according to claim 1 or 2 are controlled.