JPH08295289A - Pitch angle control method and device of controlable pitch propeller system - Google Patents

Abstract

PURPOSE: To make improvements in controllability by detecting a fact that a throttle is operated to its opening side, thereby altering the pitch angle of a propeller to the specified pitch angle as well as detecting a fact that it is operated to the closing side, thereby altering the propeller pitch angle to the minus side rather than the specified pitch angle. CONSTITUTION: A setting signal is outputted from a computing element 83 inputting each detecting signal of an engine speed detector 81 and a throttle opening detector 82, and this setting signal is compared with a measuring signal of an actual pitch angle measured by a potentiometer 85 at a controller 84. A servomotor 86 is controlled by a control signal based on this compared result, whereby the pitch angle of a propeller is altered. In brief, in the case where a throttle is opened more than the setting opening and engine speed has exceeded the upper limit of a speed setting value, the pitch angle is altered to the plus direction. On the other hand, in the case where the throttle is closed from the setting opening and the engine speed goes higher than the lower limit of the speed setting value, the pitch angle is altered toward the minus direction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for improving the kinetic performance of a small high speed boat such as a leisure motor boat or a racing motor boat which requires agile kinematic performance, and more particularly, a variable pitch propeller. The present invention relates to a method and a device for controlling a pitch angle using the device.

[0002]

2. Description of the Related Art Conventionally, a so-called variable pitch propeller device for changing a pitch angle of a propeller has been known for a propulsion device for a large ship. This conventional variable-pitch propeller device for large ships aims to make the most efficient use of the engine output to enable economical operation, and the response speed of propeller pitch angle change is large ships. Even if it is relatively slow, it will not cause any practical problems.

However, in a small and high-speed ship (hereinafter referred to as a small high-speed boat) such as a leisure motor boat or a racing motor boat, the output of the engine is effectively utilized to the maximum extent to improve the exercise performance. In order to do so, it is necessary to change the pitch angle of the propeller quickly, and for a small high-speed boat, a variable pitch propeller device must be manufactured in a small size, light weight, and low cost, but this involves great difficulty. . Therefore, in the past, some large vessels were equipped with a variable pitch propeller device, but small high speed boats were not actually equipped with a variable pitch propeller device.

However, even in a small high-speed boat, it is necessary to reduce fuel consumption and stability of running.
Being able to change the pitch angle of the propeller in a leisure motorboat will give the driver a sense of satisfaction.

Further, as the motion performance of a small high speed boat, improvement of acceleration performance is particularly important. However, in order to improve the acceleration performance, it is necessary to maximize the efficiency of the engine. Therefore, it is effective to change the pitch angle of the propeller to the minus side during acceleration to reduce the load acting on the engine and rapidly increase the engine speed. In other words, in order to improve the acceleration performance of a small high-speed boat, it is effective to rapidly raise the engine speed up to the maximum output generation range. However, in the case of a fixed pitch propeller, the engine rotational speed increases due to an increase in the rotational load of the propeller. Is prevented from rising rapidly. Therefore, it is necessary to change the pitch angle during acceleration to the negative side to reduce the rotational load acting on the propeller.

Therefore, in recent years, there is an increasing tendency to equip small high speed boats with a variable pitch propeller device.
When the variable pitch propeller device is not applied to a small high-speed boat, the structure of the variable pitch propeller device, which has been conventionally applied to a large-sized ship, is generally downsized and equipped. There is a big difference in the technical issues required for the variable pitch propeller device between the motor boat and the motor boat, and they are not always satisfactory.

Based on the above background, the present applicants have already proposed the following variable pitch propeller device,
I have applied for a patent for this. That is, FIG. 10 and FIG.
Refer to chain 1 and adjust screw 2
When is rotated, the adjusting screw 2 itself moves in the axial direction by the feed screw mechanism 3. Here, the feed screw mechanism 3 is an external screw 2 formed on the adjusting screw 2.
A is screwed into an internal screw 5 fixed to the propulsion device body 4. Although the adjusting screw 2 and the control rod 6 are connected, the rotation is not transmitted. Therefore, the control rod 6 is moved in the axial direction by the rotation of the adjusting screw 2. Then, the attachment mechanism 8A of the propeller 8 is rotated by the conversion mechanism 7 that converts the movement in the axial direction into the rotational movement, and the pitch angle is changed.

The above operation is performed while the propulsion shaft 9 is in operation, and the control rod 6 is provided so as to penetrate the center of the propulsion shaft 9. The propulsion shaft 9 is driven by transmitting the rotation of a prime mover (not shown) to the transmission shaft 10, the transmission gear 11, and the transmission gear 12 provided at the end of the propulsion shaft 9.

The above-mentioned proposed variable pitch propeller device is very useful because it has a simple structure, is small and lightweight, and allows the operator to easily operate it while manipulating a small high speed boat. It is a device that is drawing attention.

[0010]

However, the above-mentioned proposed variable pitch propeller device has the following technical problems. When the pitch angle of the propeller 8 is changed, the operator operating the small high-speed boat operates the chain 1 manually, so the operator does not only operate the throttle lever that operates the engine rotation. In addition, the steering for changing the direction must be performed, and in addition, the pitch angle changing operation must be performed. Therefore, the proposed variable pitch propeller device had some difficulties in terms of maneuverability.

Further, even in a small high-speed boat, a large propulsion force is produced in a region of the number of revolutions where the engine produces an effective output (hereinafter referred to as a power band), and at the same time, a pitch angle is set so that fuel consumption is improved. It is desirable to adopt. However, according to the manual pitch angle changing method, since it relies on the intuition of the operator, it is not always sufficient to make the most effective use of the engine output in terms of optimal propulsive force and fuel consumption. .

The present invention has been made to solve the above problems, and an object of the present invention is to automatically change the pitch angle of a propeller according to the number of revolutions of the engine and the throttle opening so that the propulsion force and It is an object of the present invention to provide a control method and device for a variable pitch propeller device for a small high speed boat, which has improved fuel economy and improved maneuverability.

[0013]

The feature of the present invention resides in that the pitch angle of the propeller is changed to a predetermined pitch angle by detecting the actuation of the throttle on the opening side, and the propeller is actuated on the closing side. A pitch angle control method in a variable pitch propeller device is characterized in that the pitch angle of the propeller is changed to a minus side from the predetermined pitch angle by detecting that the propeller is operated.

Another feature of the present invention is to detect that the engine speed becomes equal to or higher than a predetermined speed and change the pitch angle of the propeller to a predetermined pitch angle so that the engine speed becomes predetermined. A pitch angle control method in a variable pitch propeller device is characterized in that a pitch angle of the propeller is changed to a minus side from the predetermined pitch angle by detecting that the number of revolutions is equal to or less than a predetermined value.

Still another feature of the present invention is that the pitch angle of the propeller is set to a predetermined value by detecting means for detecting that the throttle opening side or the throttle closing side is operated, and a signal from the detecting means. A pitch angle control device in a variable pitch propeller device, comprising: a control mechanism for changing to a pitch angle.

Another feature of the present invention is that engine speed detecting means for detecting that the engine speed is higher than or equal to a predetermined speed or lower than a predetermined speed and transmitting a signal, and the engine. In response to a signal that the engine speed of the engine speed detection means is equal to or higher than a predetermined speed, the pitch angle of the propeller is changed to a predetermined pitch angle, and the engine speed of the engine speed detection means is equal to or lower than a predetermined speed. A pitch angle control device in a variable pitch propeller device, comprising: a control mechanism that receives a signal and changes the pitch angle of the propeller to a minus side of the predetermined pitch angle.

[0017]

1 is a sectional view showing a chain drive mechanism portion of a variable pitch propeller device according to an embodiment of the present invention, and FIG. 2 is a sectional view taken along line AA of FIG. FIG. 3 shows B of FIG.
-B is a sectional view.

Referring to FIGS. 1 to 3, the casing 2
1 is provided with a servo motor 22, and the rotary shaft of the servo motor 22 is connected to a worm 23. The worm 23 meshes with a worm wheel 25 provided on the intermediate shaft 24, whereby the rotation of the worm 23 is transmitted to the intermediate shaft 24. The intermediate shaft 24 is provided with a gear 26, which meshes with a transmission gear 28 provided on a drive shaft 27. This allows the intermediate shaft 24
Is transmitted to the drive shaft 27. A disc-shaped winding body 29 is provided on the drive shaft 27, and a chain 30 is wound around the winding body 29. The chain 30 is the same as the previously proposed chain shown in FIGS. Since the mechanism for changing the pitch angle of the propeller by the chain 30 is the same as the already proposed mechanism, the drawings of FIGS. 10 to 13 will be borrowed and the description thereof will be omitted. The chain 30 operates in the same manner even if it is replaced with a cable or the like. The drive shaft 27 has a potentiometer 31
Is provided, and the potentiometer 31 has a drive shaft 2
The rotation angle of 7 is detected.

Next, one embodiment of the control device for controlling the rotation of the servo motor 22 will be described with reference to FIG. The switch circuit 41 sends a control signal to the control circuit 42. The control circuit 42 sends a signal to the servo motor drive unit 43, and the servo motor drive unit 43 rotationally drives the servo motor 44. The switch circuit 41 is interlocked with a throttle lever 45, and the switch circuit 41 is activated when the throttle lever 45 reaches a predetermined opening. Limit switches 46 and 47 are provided on the side of the throttle lever 45.
The limit switches 46 and 47 are turned on and off according to the operation of 5. It should be noted that the limit switches 46 and 47 operate in the same manner even if, for example, a potentiometer (not shown) is provided on the rotary shaft of the throttle lever, and the operation amount of the throttle lever (throttle opening) is detected by the potentiometer. .

Next, the operation of the above control device will be described. When the engine is idling, the pitch angle of the propeller is changed (held) to the minus side of the reference pitch angle. Therefore, the propelling force of the propeller is small.

Now, when the throttle lever 45 is actuated to move the engine in the direction of increasing the engine speed (throttle opening side), the limit switch 46 is actuated. Then
The switch circuit 41 operates to send a control signal to the control circuit 42. Here, since the switch circuit 41 is provided with a timer described later, the switch circuit 41 transmits to the control circuit 42 with a delay of a predetermined time. For this reason,
Since the pitch of the propeller is changed with a predetermined time delay by operating the throttle lever 25, the load acting on the propeller immediately after operating the throttle lever is small and does not hinder a rapid increase in engine speed. The setting of the delay time by the timer can be arbitrarily adopted. Further, the timer is not always necessary, and the speed at which the pitch angle of the propeller is changed may be controlled. .

The control circuit 42 sends a signal to the servo motor drive section 43, and the servo motor 44 advances the pitch angle of the propeller to the plus side (toward the reference pitch angle) by the output of the servo motor drive section 43. Therefore, the pitch angle of the propeller is automatically controlled to be shifted to the reference pitch angle in a region where the engine speed is high. At this time, it is desirable that the rotation speed range in which the pitch angle of the propeller is shifted to the reference pitch angle is set within the power band by setting the timer or the like.

The state in which the reference pitch angle is changed is maintained until the limit switch 47 is operated by returning the throttle lever 45 to the side where the throttle is closed. Therefore, it will not be released by operating the throttle lever 45 to some extent.

If the throttle lever 45 is returned to the side where the throttle is closed, as in the case where the small high-speed boat is rapidly turning from a state of running at high speed, the limit switch 47 is activated. Then, the switch circuit 41 operates to control the control circuit 42 and the servo motor drive unit 43.
The servomotor 44 is actuated via the, and the propeller is rotated in the direction in which the pitch angle returns to the minus side. Since the switch circuit 41 is provided with a timer described later, the switch circuit 41 transmits to the control circuit 42 with a delay of a predetermined time. For this reason, a rapid decrease in the engine speed acts on the propeller, which causes a kind of engine braking effect, resulting in a rapid decrease in ship speed. The setting of the delay time by the timer can be arbitrarily adopted, and if the propeller is rotated so as to return the pitch angle to the minus side with no time delay or with a short time delay, the engine speed will be reduced. The thrust acting on the propeller rapidly decreases without lowering, and the ship speed decreases rapidly. Further, when there is no time delay, this timer is not always necessary, and can be omitted.

The switch circuit 41 is a sequence circuit, and an embodiment of the sequence diagram will be described with reference to FIG.

The switches SL1 and SL2 are limit switches 4 provided on the sides of the throttle lever shown in FIG.
The switches SL6 and S47 are opened and closed. The switch SL1 is a normally open switch and the switch SL2 is a normally closed switch. Now, when the switch SL1 is closed by operating the throttle lever, X1 (relay) is activated. X
Since 1 (relay) closes the relay switch X1 for self-holding provided in the circuit on the side of the switch SL2,
Once activated, X1 (relay) is held until switch SL2 is opened. Next, when X1 (relay) is activated, the relay switch X provided in the circuit of the timer T1.
1 activates the timer T1. The timer T1 can set an arbitrary time, and after the time set by the timer T1 elapses, the relay switch T1 is closed and X2 is set.
(Relay) is activated. Since the operated X2 (relay) is self-held by the relay switch X2 and the normally closed relay switch X3, the operation of X2 (relay) is self-held until the relay switch X3 is opened. The relay switch X3 actuates U (relay) to actuate U (contact) of a control circuit (same as the control circuit 42 of FIG. 4) shown in FIG. 6 described later. (In this example, the contact opens.)

The above sequence is the sequence up to the operation of the control circuit. Next, the sequence when the switch SL2 is opened will be described. X when switch SL2 opens
1 (relay) is deactivated, and the normally closed relay switch X1 provided in the circuit of the timer T2 is closed. The timer T2 is activated. After the lapse of the time set by the timer T2, the relay switch T2 is closed and X3 (relay) is activated. Then, the normally closed relay switch X3 provided in the self-holding circuit of X2 (relay) opens. Therefore, the operation of X2 (relay) is released, the relay switch X2 is opened, and the operation of U (relay) is released. Then, the U (relay) of the control circuit is activated. (In the case of this embodiment, the contacts are closed.)

Next, a control circuit according to an embodiment of the present invention will be described with reference to FIG. The signals of the pitch angle reference setting device 62 and the pitch angle change range setting device 63 are input to the comparator 61 on the one hand, and the potentiometer 64 on the other hand.
Actual pitch angle measurements from (same as potentiometer 31 in FIGS. 1-3) are input and compared. Here, the normally closed contact U is operated (opened and closed) by the U (relay) described in the switch circuit of FIG. Here, the pitch angle reference setter 62 sets the reference angle of the pitch angle. For example, the pitch angle of the propeller is preset from the reference pitch angle to the most plus side position of the pitch angle change range. To put. The pitch angle changing range setter 63 sets the angle when the pitch angle of the propeller is most advanced to the minus side from the reference pitch angle, for example. To the comparator 61, the reference angle set by the pitch angle reference setting device 62 is subtracted by the pitch angle in the range set by the pitch angle change range setting device 63, and the result is input.

Signal (voltage) output from the comparator 61
Is input to the pair of comparators 65 and 66.
The output of a setting device 67 that outputs a plus side allowance signal of the pitch angle set value is input to one comparator 65, and the other comparator 66 is set to output a minus side allowance signal of the pitch angle set value. The output of the comparator 68 is input and compared with the output of the comparator 61. The plus side allowance value signal or the minus side allowance value signal of the pitch angle set value is the control target value of the pitch angle set by the pitch angle reference setting device 62 and the pitch angle change range setting device 63. The upper limit and the lower limit are set in order to achieve the above with a predetermined width. For example, when the control target value of the pitch angle is set to 35 degrees, the actual pitch angle is 33 degrees as the lower limit and 37 degrees as the upper limit. If it is within the range, it is controlled as if it is within the control target value. This prevents hunting of the control operation.

When the positive side allowable value voltage of the setter 67 becomes higher than the output voltage of the comparator 61, the coil R closes the relay switch R of FIG.
The MR (relay) is used to issue a command to drive the servo motor in reverse. When the negative side allowable value voltage of the setter 68 becomes smaller (lower) than the output voltage of the comparator 61, the coil F closes the relay switch F in FIG. 5, and the MF (relay) makes the servomotor positive. It issues a command for rolling drive.

Here, since the setters 67 and 68 are variable resistors, it is possible to output an arbitrary voltage by turning a knob, for example, to set an arbitrary allowable value width. When the servo motor rotates and the pitch angle is changed, the output of the potentiometer 64 is changed and the output voltage from the comparator 61 is changed. Then, when the voltage output from the comparator 61 falls within the set values of the setter 67 and the setter 68, the servo motor stops.

Although the embodiment described above changes the pitch angle of the propeller by interlocking with the throttle lever of the engine, the present invention is not limited to the system interlocking with the throttle lever. For example, by detecting the engine speed, converting the voltage value into a voltage value, and importing the voltage value into the control unit, it is possible to perform pitch angle change control based on the engine speed instead of the throttle opening. An apparatus for changing and controlling the pitch angle of the propeller in conjunction with the engine speed will be described below.

In general, it is preferable to use a marine engine in the rotation speed range (power band) where the output is the highest. When the engine speed is within the power band range, the propeller is run with the pitch angle of the propeller being the most propulsive force and at the same time having the most fuel efficient pitch angle (reference pitch angle). Therefore, in the method of automatically controlling the pitch angle of the propeller by the engine speed, the pitch angle of the propeller is controlled so as to become the reference pitch angle when the engine speed is within the power band, and the engine speed is within the power band. The pitch angle of the propeller is controlled so that it is maintained at.

An example of a control device for performing the above control operation is
This will be described below with reference to FIG. Referring to FIG. 7, an output signal of a rotation speed detector 71 for detecting the engine rotation speed and an output signal of an engine rotation speed setting device 72 for setting a power band of the engine rotation speed are input to a comparator 73. Comparator 73
When the actual engine speed exceeds a preset upper limit of the power band, the servo motor 74 is actuated so that the pitch angle of the propeller becomes the reference pitch angle. When the number of engine revolutions set in advance becomes smaller than the lower limit of the power band, the servo motor 74 is operated in the reverse direction to change the pitch angle of the propeller from the reference pitch angle to the minus side.

The operation of the control device will be described. When the engine is in the idling state, the engine speed is outside the lower limit of the power band, so the pitch angle of the propeller is changed from the reference pitch angle to the minus side. Has become.

If the throttle lever (not shown) is actuated to open the throttle, the engine speed will increase. Here, when the actual engine speed is detected, and when the actual engine speed is still outside the lower limit of the power band, the pitch angle of the propeller is maintained in the state changed from the reference pitch angle to the minus side. Therefore, the engine speed increases rapidly. Then, when the actual engine speed exceeds the upper limit of the power band of the engine speed, the comparator 73 operates the servo motor 74 to advance the pitch angle of the propeller in the direction of the reference pitch angle. In this way, the engine speed rapidly increases, and then the pitch angle of the propeller becomes the reference pitch angle, so that the acceleration performance of the motor boat or the like is improved.

When the motor boat or the like is rotating rapidly at a high speed, the throttle lever is operated to close the throttle. Then, the engine speed decreases, and the actual engine speed falls outside the lower limit of the power band. When the engine speed falls below the lower limit of the power band, the servo motor 74 operates in the reverse direction by the output of the comparator 73, and the pitch angle of the propeller is changed from the reference pitch angle to the minus side. Then, when the throttle lever is opened again to open the throttle, the engine speed rapidly rises and a rapid acceleration is obtained.

The control mechanism explained in FIG. 7 is shown in FIG.
6 and includes a switch circuit and a control circuit as shown in FIG. In this case, the switch SL1 and the switch SL2 of FIG. 5 may be opened and closed by the rotation speed detector of FIG. 7 (when the engine speed exceeds the upper limit of the power band, the switch SL1 is closed,
When the engine speed is lower than the lower limit of the power band, the switch SL2 is opened. ), The detailed description of the structure and operation thereof is the same, and will be omitted.

In the embodiment described above, the pitch angle of the propeller is changed to the reference pitch angle (pitch angle for high-speed cruising) and the pitch changed to the minus side by the signal of the throttle opening or the signal of the engine speed. The present invention relates to a method device for controlling two types of angle (acceleration pitch angle), but the present invention is not limited to the above embodiment, and the following throttle opening signal and engine speed It also includes a pitch angle control method and apparatus using both signals.

That is, referring to FIG. 8, the signals from the engine speed detector 81 for detecting the engine speed and the throttle opening detector 82 for detecting the throttle opening are input to the calculator 83. The output of the arithmetic unit 83 is input to the controller 84 (same as the controller 61 of FIG. 6) as a setting signal. On the other hand, the actual pitch angle measured by the potentiometer 85 is input to the controller 84 as a measurement signal, and the calculator 8
The controller 84 compares the setting signal, which is the output of No. 3, with the measurement signal, which is the output of the potentiometer 85. Then, the servo motor 86 is operated by the output signal of the controller 84, and the pitch angle of the propeller is changed by the servo motor 86.

The control apparatus shown in FIG. 8 is the same as the control apparatus shown in FIGS. 4 to 6 except that the engine speed signal is added in parallel with the throttle opening signal.
A signal is input to (the same as the controller 61 of FIG. 6), and the servo motor 86 (the same as the servo motor 44 of FIG. 4) is driven by the throttle opening signal and the engine speed signal as described later. It controls the rotation.

The operation of the method and apparatus for controlling the pitch angle of the propeller based on the throttle opening and the engine speed shown in FIG. 8 will be described below. Referring also to the switch circuit shown in FIG. 9, assuming that the throttle is opened more than the set opening degree, the contact F is closed and the engine speed exceeds the upper limit of the speed setting value (power band). And contact F2
Also close and change the pitch angle toward the plus (reference pitch) direction. On the other hand, when the opening of the throttle is closed from the set opening, the contact R is closed, and when the engine speed falls below the lower limit of the set speed (power band), the contact R2 is closed and the pitch angle Change toward minus. Therefore, the pitch angle of the propeller can be controlled from both the opening and closing of the throttle and the engine speed simply by adding the contacts F2 and R2 that open and close according to the engine speed to the switch circuit shown in FIG.

[0043]

According to the present invention constructed as described above, the following effects can be obtained. Since the pitch angle of the propeller is automatically changed, the operator can concentrate on only the throttle lever and steering, improving maneuverability and safety. With a timer, it is possible to improve acceleration and obtain engine braking.

[Brief description of drawings]

FIG. 1 is a front view showing a control device of a variable pitch propeller device according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along the line AA of FIG.

3 is a sectional view taken along line BB of FIG.

FIG. 4 is a block diagram of a throttle lever interlocking control device according to an embodiment of the present invention.

FIG. 5 is a sequence diagram showing an example of a switch circuit applied to the present invention.

FIG. 6 is a diagram showing an example of a control circuit applied to the present invention.

FIG. 7 is a block diagram showing an example of an engine speed linked control device according to an embodiment of the present invention.

FIG. 8 is a block diagram showing a pitch angle control device according to both a throttle opening and an engine speed according to an embodiment of the present invention.

9 is a diagram showing one embodiment of a switch circuit for implementing the sequence of the control device of FIG.

FIG. 10 is a sectional view of a proposed variable pitch propeller device.

11 is a sectional view taken along line CC of FIG.

12 is a cross-sectional view taken along the line DD of FIG.

FIG. 13 is a cross-sectional view showing a rotation mechanism by chain.

[Explanation of symbols]

 21 casing 22 servo motor 23 worm 24 intermediate shaft 25 worm wheel 26 gear 27 drive shaft 28 transmission gear 29 winding body 30 chain 31 potentiometer 41 switch circuit 42 control circuit 43 servo motor drive unit 44 servo motor 45 throttle lever 46 limit Switch 47 Limit switch 61 Comparator 62 Pitch angle reference setting device 63 Pitch angle change range setting device 64 Potentiometer 65 Comparator 66 Comparator 67 Setting device 68 Setting device 71 Rotation speed detector 72 Engine speed setting device 73 Comparator 74 Servo Motor 81 Engine speed detector 82 Throttle opening detector 83 Computing device 84 Controller 85 Potentiometer 86 Servo motor

Claims (8)

[Claims] 1. A pitch angle of the propeller is detected by detecting that the throttle is opened, and a pitch angle of the propeller is changed to a predetermined pitch angle, and a pitch angle of the propeller is detected by detecting that the throttle is closed. A pitch angle control method in a variable pitch propeller device, wherein the pitch angle is changed to a minus side from a predetermined pitch angle. 2. The variable according to claim 1, wherein the pitch angle of the propeller is changed to a predetermined pitch angle with a delay of a predetermined time after it is detected that the throttle has been operated to the opening side. A pitch angle control method in a pitch propeller device. 3. The pitch angle of the propeller is changed to a minus side from the predetermined pitch angle after a delay of a predetermined time after detecting that the throttle has been operated to the closing side. A pitch angle control method for a variable pitch propeller device according to claim 1 or 2. 4. An engine speed is detected to be equal to or higher than a predetermined speed and a propeller pitch angle is changed to a predetermined pitch angle to detect that the engine speed is equal to or lower than a predetermined speed. Then, the pitch angle of the propeller is changed to a minus side from the predetermined pitch angle, a pitch angle control method in a variable pitch propeller device. 5. A degree of opening and closing of a throttle and an engine speed are detected, and when the throttle is operating to a side opening more than a set opening, it is detected that the engine speed is equal to or higher than a predetermined speed. After that, when the pitch angle of the propeller is changed to a predetermined pitch angle, and when the throttle is operating on the side closer than the predetermined opening, it is detected that the engine speed becomes equal to or lower than a predetermined speed, A pitch angle control method in a variable pitch propeller device, wherein the pitch angle of the propeller is changed to a minus side from the predetermined pitch angle. 6. A detection means for detecting whether the throttle is operated to open or close, and a control mechanism for changing the pitch angle of the propeller to a predetermined pitch angle in response to a signal from the detection means. A pitch angle control device for a variable pitch propeller device. 7. The control mechanism is provided with a timer for changing the pitch angle of the propeller to a predetermined pitch angle with a delay of a predetermined time after receiving a signal from the detecting means. Angle control device in the variable pitch propeller device of the. 8. An engine speed detecting means for detecting that the engine speed is equal to or higher than a predetermined speed or lower than a predetermined speed and transmitting a signal, and the engine speed of the engine speed detecting means is The pitch angle of the propeller is changed to a predetermined pitch angle in response to a signal of a predetermined rotation speed or more, and the pitch angle of the propeller is received in response to a signal of the engine rotation speed of the engine rotation speed detecting means being a predetermined rotation speed or less. And a control mechanism for changing the above to a minus side from the predetermined pitch angle, a pitch angle control device in a variable pitch propeller device.