JPH0141559B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a constant speed control device for an output shaft of a marine gear for a ship.

In general, when a fishing boat is trolling or when a work boat has to stop at a point on the sea against the force of currents or wind to avoid being swept away, the marine gear should be set to the lowest position. It is required to stably obtain a speed even lower than the idling speed.

For this reason, a constant speed control device for the output shaft of a marine gear for a ship has conventionally been used in which the connection between the engine shaft and the output shaft is controlled at a low speed in a half-clutched state.

For example, as shown in FIG. 1, a conventional constant speed control device uses a hydraulic pump 2 and a forward clutch 6 to control hydraulic pressure.
Alternatively, a low speed valve 4 and a centrifugal governor 9A are provided between the forward/reverse switching valve 3 that switches to the reverse clutch 7, and the centrifugal governor 9A detects the rotational speed of the output shaft (propeller shaft) 9. The low-speed valve 4 is adjusted accordingly, the clutches 6 and 7 are brought into a half-clutch state, and a preset output shaft rotational speed is obtained, and the rotational speed of the output shaft is set by the operation position of the speed command lever 4a of the low-speed valve 4. In addition, when the low speed valve 4 is not required, the full discharge pressure of the pump is bypassed through the low speed valve 4, and the full pressure is applied to the forward or reverse clutch via the forward/reverse switching valve 3, and the clutch is directly connected. The configuration was such that the rotation speed of the output shaft was multiplied by the gear ratio of the rotation of the engine shaft.

However, in this type of conventional constant speed control device, the hydraulic circuit for operating the centrifugal governor is complicated, and when setting the rotational speed of the output shaft, the speed command lever 4a of the low speed valve 4 must be directly operated. Therefore, there was a drawback that it was difficult to change the set speed while working.

The present invention uses a simple control circuit without using conventional low-speed valves or centrifugal governors, and controls the oil flow from the hydraulic pump according to the deviation between the rotational speed of the output shaft and the set speed. The clutch oil pressure in a half-clutch state is controlled by adjusting the opening/closing control of a solenoid valve, and a bypass valve is provided to bypass the solenoid valve, so that the bypass valve is automatically operated when the deviation is larger than a predetermined value. The present invention provides a constant speed control device for the output shaft of a marine gear for ships.

FIG. 2 shows an embodiment of the constant speed control device for the output shaft of a marine gear for ships according to the present invention.
The difference from the conventional constant speed control device shown in the figure is that a pick-up 22 detects the rotational speed of the output shaft without using a centrifugal governor or a low-speed valve, a speed setting device 25 sets the speed to a predetermined speed, and a pick-up 22
a control circuit 24 that outputs a signal according to the deviation between the output of the speed setter 25 and the output of the speed setting device 25; a normally open solenoid valve 20 that adjusts the passing oil pressure according to the deviation signal; The present invention includes a bypass valve 21 that bypasses the solenoid valve 20.

In the bypass valve 21, the input port _P1 is connected to the solenoid valve 20, the input port _P2 is connected to the hydraulic pump 2,
Further, the output port _P3 is connected to the clutches 6 and 7 via the forward/reverse switching valve 3, respectively. Then, the oil flow whose pressure is regulated by the pressure regulating solenoid valve 20 is introduced into the input port _P1 , and the spool 21a is moved in accordance with the magnitude of this flow pressure, so that the output port
The input port connected to P ₃ is switched to either input port P ₁ or P ₂ .

For example, when the bypass valve 21 is in the spool position shown in FIG. 2, oil is flowing from the hydraulic pump 2 from the electromagnetic valve 20 to the input port P ₁ of the bypass valve 21 to the output port P _{3 of} the bypass valve 21.

In this state, the solenoid valve 20 is alternately switched between the positions 20A and 20B in response to a control signal from the control circuit 24 to regulate the pressure of the oil flow from the hydraulic pump 2.

Also, the spool position of the bypass valve 21 is
When moving to the right from the position shown in the figure, closing input port _P1 and opening input port _P2 ,
Hydraulic pump 2 → bypass valve 21 input port
In this state, oil is flowing from P ₂ to the output port P ₃ of the bypass valve 21, bypassing the solenoid valve 20. This state occurs when the signal-based deviation between the set speed and the detected speed exceeds the predetermined value.

FIG. 3 shows details _of the control circuit shown in FIG.
5 is for adjusting to a predetermined speed Np, and outputs a signal Es corresponding to the speed Np.

Deviation △e obtained by comparing the signals Es and Ep
(Δe=Es−Ep) is amplified by the amplifier 32 and output to the comparison circuit 34 as the deviation signal _e1 . As shown in FIG. 4a, the triangular wave signal e ₂ output from the triangular wave generating circuit 33 is combined with the deviation signal e ₁ from the comparing circuit 34.
As shown in FIG. 4b, the control signal e 3 is high level for t ₁ hour of e ₂ e ₁ and low level for t ₂ hour of e ₂ < e ₁ , and is sent to the solenoid valve drive circuit ₃₆ .
Output to. Note that here, the low level time
_t2 corresponds to the magnitude of the deviation signal _e1 .

The solenoid valve drive circuit 36 is for switching the position of the solenoid valve 20 according to the level of the control signal _e3 ,
Since the solenoid valve 20 is normally open, it is switched to the open position 20B when the level is low and to the closed position 20A when the level is high.

Next, an example of the operating principle of the bypass valve according to the present invention will be explained with reference to FIG.

A biasing force is applied to the spool 21a of the bypass valve 21 in the direction of arrow B in the figure by a spring 21b, and the spool 21a is always connected to the hollow chamber 21C of the valve 21 through the input port _P1 from the solenoid valve 20.
Flow pressure is applied in the direction of arrow A in the figure by the oil flow flowing into the pipe. The spool 21a is then moved to a position where the fluid pressure in the hollow chamber 21C and the biasing force are balanced.

Therefore, when the fluid pressure to the hollow chamber 21C increases, the spool 21a moves in the direction of arrow A, and when it decreases, the spool 21a moves in the direction of arrow B.

By the way, the fluid pressure to the hollow chamber 21C is controlled by the solenoid valve 20.
This corresponds to the oil flow rate from to the input port _P1 , and this oil flow rate corresponds to the time during which the solenoid valve 20 is switched to the open position 20B, that is, the low level time _t2 of the aforementioned control signal _e3 (Fig. 4b). It corresponds to

Therefore, the fluid pressure to the hollow chamber 21C is determined corresponding to the low level time _t2 of the control signal _e3 described above.

Now, the predetermined time t ₀ where the above-mentioned low level time t ₂ exists
It is assumed that when the value exceeds , the fluid pressure to the corresponding hollow chamber 21C increases and the position of the spool 21a moves to a critical position where the input port _P1 is closed and the input port _P2 is opened.

When _the spool 21a _is in the _position shown in _FIG . , 7, the clutch becomes a half-clutch state, and the rotational speed of the output shaft is controlled to the set speed.

Furthermore _, when _{the spool} 21a moves in the direction of arrow _A from the position shown in FIG. The full discharge pressure of 2 is applied to the output port _P3 , the clutch is directly connected, and the rotational speed of the output shaft is controlled so as to rapidly reach the set speed.

A thermal sensor 23 immersed in the clutch hydraulic oil 12 is used to prevent the clutch from burning out. When the temperature T of the hydraulic oil 12 exceeds a predetermined temperature Ts, the comparator 38 generates a signal S. The switch 37 is opened, the solenoid valve 20 is set to the open position 20B, and the full discharge pressure of the hydraulic pump 2 is applied to the clutches 6 and 7 to connect them directly, thereby preventing a temperature rise in the clutches.

In this case, instead of directly connecting the clutch, the clutch may be completely disconnected when the signal S is generated.

As explained above, according to the present invention, since the clutch hydraulic pressure is electrically controlled, speed adjustment becomes easy, and if the speed setting device is made compact and movable, the speed can be adjusted while working.
The bypass valve has great effects, such as being able to further improve the ability to follow the set speed and constructing a simple, inexpensive, and highly reliable constant speed control device.

[Brief explanation of drawings]

FIG. 1 is a diagram showing a conventional constant speed control device for the output shaft of a marine gear for ships, FIG. 2 is a diagram showing an embodiment of the constant speed control device for the output shaft of a marine gear for ships according to the present invention, and FIG. 4 is a block diagram showing an embodiment of the control circuit of FIG. 2, FIGS. 4a and 4b are diagrams showing the principle of generation of the output signal of the control circuit of FIG. 3, and FIG. FIG. 1... Engine, 2... Hydraulic pump, 3... Forward/forward switching valve, 5... Marine gear, 6, 7... Clutch, 9... Propeller shaft, 20... Solenoid valve, 21
...Bypass valve, 22...Pickup, 2
3...Thermal sensor, 24...Control circuit, 25
...Speed setting device.

Claims (1)

[Scope of Claims] 1. A constant speed control device for the output shaft of a marine gear, which includes a speed detector that detects the screw rotation speed and outputs a corresponding speed signal, a setting device that sets the screw rotation speed, and a detected speed signal. A control device that outputs a control signal according to the deviation between the speed signal and the set speed signal, a bypass valve provided on the hydraulic pump side of the forward/reverse switching valve, and a bypass valve provided between one input port of the bypass valve and the hydraulic pump. If the deviation is within a specified value, the hydraulic pressure is adjusted by the solenoid valve, and this hydraulic pressure is applied to the clutch via the forward/reverse switching valve to control a half-clutch state, and when the deviation exceeds the specified value, This is a constant speed control device for the output shaft of a marine gear that bypasses the solenoid valve and rapidly increases clutch pressure to directly connect the clutch pressure. 2. In a constant speed control device for the output shaft of a marine gear, there is a speed detector that detects the screw rotation speed and outputs a corresponding speed signal, a setting device that sets the screw rotation speed, and a combination of the detected speed signal and the set speed signal. A control device that outputs a control signal according to the deviation, a bypass valve provided on the hydraulic pump side of the forward/reverse switching valve, a solenoid valve provided between one input port of this bypass valve and the hydraulic pump, and a clutch. It is equipped with a thermal sensor that detects the temperature of the hydraulic oil, and means that disconnects the solenoid valve from the control signal and switches it to the open position when the detected temperature exceeds a predetermined value.When the clutch temperature exceeds a predetermined value, the clutch pressure is increased and the clutch is directly connected. A constant speed control device for the output shaft of marine gear.