JPH0516886A - Hydraulic circuit of power tilt-trim system - Google Patents

Abstract

PURPOSE:To prevent dust or the like from being left over in an oil passage by making a hydraulic fluid being discharged out of a cylinder so as to go back to a tank without fail. CONSTITUTION:Each discharge port of a reversible type hydraulic pump 12 is connected to each of oil chambers S1, S2 of a cylinder 1 via two check valves 16, 17 checking a flow of hydraulic fluid in the inflow direction, while each of these oil chambers S1, S2 of the cylinder 1 is connected to a tank 15 via two counter valves 22, 24, through which these counter valves 22, 24 are made so as to be an opened state by dint of pilot pressure at each discharge side of the hydraulic pump 12.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic circuit of a power tilt / trim device used for an outboard motor of a ship.

[0002]

2. Description of the Related Art In a small boat such as a motor boat,
A power tilt / trim device having a tilt cylinder for raising and lowering the outboard motor above the water surface and a trim cylinder for changing the angle of the outboard motor in water is provided. A hydraulic circuit for such a power tilt / trim device is disclosed in, for example, Japanese Patent Publication No. 3-1199.

The conventional hydraulic circuit will be described with reference to FIG. 3. When the reversible hydraulic pump 102 is normally rotated by the motor 101, the tilt cylinder 106 is provided in parallel via the pilot spool valve 105, for example. Lower chamber S1 and lower chambers S3 of the two trim cylinders 107
Is supplied to the upper chamber S2 of the tilt cylinder 106.
The hydraulic oil in the upper chambers S4 of the two trim cylinders 107 returns to the hydraulic pump 102 via the pilot spool valve 105, and the outboard motor is up-operated.

By rotating the hydraulic pump 102 in the reverse direction, hydraulic oil is supplied to the upper chamber S2 of the tilt cylinder 106 and the upper chambers S4 of the two trim cylinders 107 via the pilot spool valve 105, and the tilt cylinder is rotated. The hydraulic oil in the lower chamber S1 of 106 and the lower chamber S3 of each of the two trim cylinders 107 is transferred to the pilot spool valve 10
Returning to the hydraulic pump 102 via 5, the down operation of the outboard motor is performed.

In this hydraulic circuit, the hydraulic oil corresponding to the rod withdrawal of each cylinder 106, 107 is sucked into the hydraulic pump 102 from the tank 103 via the filter 104 during the up operation, and each cylinder 106, 107 is operated during the down operation. The hydraulic oil corresponding to the rod entry volume of the above returns to the tank 103 via the blow valve 108.

[0006]

However, in the hydraulic circuit of the conventional power tilt / trim device as described above, the working oil flows from the upper chamber to the lower chamber of the cylinder, or from the lower chamber to the upper chamber, Since the hydraulic oil that is insufficient or excess due to the withdrawal and entry of the rod only returns to the tank, it is difficult for dust, foreign matter, air, etc. in the circuit to be discharged from the circuit, resulting in deterioration in function and performance.

[0007]

In order to solve the above-mentioned problems, the present invention connects each discharge port of a hydraulic pump to each oil chamber of a cylinder through a check valve that blocks the flow of hydraulic oil in the inflow direction. At the same time, each oil chamber of the cylinder was connected to a tank via a counter valve, and each counter valve was opened by each discharge side pilot pressure of the hydraulic pump.

[0008]

When the hydraulic pump is driven, the hydraulic oil discharged from the hydraulic pump flows into the oil chamber of one of the cylinders via the check valve, and the hydraulic oil of the other oil chamber of the cylinder is hydraulically operated by the check valve. Since it does not return to the pump but returns to the tank via the counter valve that is opened by the discharge side pilot pressure of the hydraulic pump, the working oil discharged from the cylinder always returns to the tank.

[0009]

Embodiments of the present invention will be described below with reference to the accompanying drawings. Here, FIG. 1 is a hydraulic circuit diagram for explaining an up operation of the power tilt / trim device to which the present invention is applied, and FIG. 2 is a hydraulic circuit diagram for explaining a down operation of the device.

The power tilt / trim device comprises a tilt cylinder 1 and two trim cylinder units 2 and 2 arranged on both sides of the tilt cylinder 1.
Is a cylinder 3 in which a piston 4 is slidably mounted to define a lower chamber S1 and an upper chamber S2. The piston 4 has a built-in one-way valve and is connected with a tilt rod 5.
The trim cylinder 2 has a piston 7 slidably fitted in the cylinder 6 to define a lower chamber S3 and an upper chamber S4, and a trim rod 8 is connected to the piston 7.

In the hydraulic circuit, each discharge port of the reversible hydraulic pump 12 which is rotationally driven by the motor 11 is connected to a tank 15 via check valves 13a and 13b and a filter 14.
Connected to. Further, one of the discharge ports of the hydraulic pump 12 is connected to the lower chambers S1 and S3 of the tilt cylinder 1 and the trim cylinder 2 via the first check valve 16 and the other is connected to the lower chamber S1 via the second check valve 17. It is connected to the upper chamber S2 of the tilt cylinder 1 and to each upper chamber S4 of the trim cylinder 2 via a relief valve 18 that opens when the discharge pressure exceeds a predetermined value. The trim cylinder 2 is provided between the chamber S4 and the upper chamber S2 of the tilt cylinder 1.
From the side of the tilt cylinder 1 to the side of the tilt cylinder 1 via a third check valve 19 that allows only the flow of hydraulic oil.

Further, the hydraulic pump 12 and each cylinder 1, 2
The oil passage connecting each of the lower chambers S1 and S3 of the first branch valve is branched from the first check valve 16 on the cylinder side and is connected to the tank 15 via the first filter 21 and the first counter valve 22.
2 and the upper chambers S2 and S4 of the cylinders 1 and 2 branch on the cylinder side from the second check valve 17 to the tank 15 via the second filter 23 and the second counter valve 24. Connected.

The first counter valve 22 uses the discharge pressure when the hydraulic oil is supplied from the hydraulic pump 12 to the upper chambers S2 and S4 of the cylinders 1 and 2 as a pilot pressure and is used as a spool 22a.
Moves to open the check valve 22b to be in the open state, and the second counter valve 24 controls the discharge pressure when the hydraulic oil is supplied from the hydraulic pump 12 to the lower chambers S1 and S3 of the cylinders 1 and 2. As the pilot pressure, the spool 24a moves to open the check valve 24b and open it.

Further, the lower chamber S1 and the upper chamber S2 of the tilt cylinder 1 and the lower chamber S3 and the upper chamber S4 of the trim cylinder 2 are connected to the tank 15 via a manual valve 26, respectively.
Further, the lower chambers S1 and S3 of the cylinders 1 and 2 are connected to the tank 15 via an up relief valve 27, and the hydraulic pump 1
The second check valve 17 and the second check valve 17 are connected to the tank 15 via a down relief valve 28.

The operation of the hydraulic circuit of the tilt / trim device configured as described above will be described below. First, during the up operation, the hydraulic oil flows as shown by the arrow in FIG.
That is, by driving the motor 11 to rotate the hydraulic pump 12 in the forward direction, the working oil from the tank 15 is filtered by the filter 14.
And is sucked by the hydraulic pump 12 via the check valve 13a, flows from the hydraulic pump 12 into the lower chamber S1 of the tilt cylinder 1 via the first check valve 16, and into the lower chamber S3 of the trim cylinder 2. Inflow.

On the other hand, the hydraulic fluid in the upper chamber S2 of the tilt cylinder 1 is prevented from returning to the hydraulic pump 12 by the second check valve 17, and the second counter valve 24 is opened by the discharge pressure from the hydraulic pump 12. Therefore, the second filter 23
And it returns to the tank 15 via the second counter valve 24. Further, since the hydraulic oil in the upper chamber S4 of the trim cylinder 2 is also prevented from returning to the hydraulic pump 12 by the relief valve 18, the second check filter 23 and the second filter 23 are similarly provided via the third check valve 19. Return to the tank 15 through the counter valve 24.

As a result, the trim rod 8 of the trim cylinder 2 extends and the tilt rod 5 of the tilt cylinder 1 extends, so that the outboard motor rises (up operation). At this time, the tilt cylinder 1 and the trim cylinder 2
The hydraulic oil discharged from each of the upper chambers S2 and S4 is returned to the tank 15 without returning to the hydraulic pump 12.

Next, during the down operation, the hydraulic oil flows as shown by the arrow in FIG. That is, by driving the motor 11 to rotate the hydraulic pump 12 in the reverse direction, the hydraulic oil is sucked from the tank 15 to the hydraulic pump 12 via the filter 14 and the check valve 13b, and the hydraulic pump 12 is driven by the second reverse pump. It flows into the upper chamber S2 of the tilt cylinder 1 via the stop valve 17. On the other hand, the hydraulic fluid in the lower chamber S1 of the tilt cylinder 1 is prevented from returning to the hydraulic pump 12 by the first check valve 16, and the first counter valve 22 is opened by the discharge pressure from the hydraulic pump 12. Therefore, it returns to the tank 15 via the first filter 21 and the first counter valve 22.

At this time, a relief valve 18 which is not opened until the discharge pressure exceeds a predetermined value is provided between the hydraulic pump 12 and each upper chamber S4 of the trim cylinder 2, and the upper chamber of the tilt cylinder 1 is provided. Since the third check valve 19 separates from S2, hydraulic oil does not flow into the upper chamber S4 of the trim cylinder 2 until the discharge pressure exceeds a predetermined value. When the discharge pressure of the hydraulic pump 12 exceeds a predetermined value, the working oil flows into each upper chamber S4 of the trim cylinder 2 via the relief valve 18, while the working oil in the lower chamber S3 of the trim cylinder 2 is discharged. Similarly, it returns to the tank 15 through the first filter 21 and the 21st unter valve 22.

As a result, first, the tilt rod 5 of the tilt cylinder 1 contracts, and then the trim rod 8 of the trim cylinder 2 contracts, and the outboard motor descends (down operation).
At this time, the hydraulic oil discharged from the lower chambers S1 and S3 of the tilt cylinder 1 and the trim cylinder 2 is the hydraulic pump 12
Instead of returning to the tank, it is returned to the tank 15.

[0021]

As described above, according to the present invention,
Each discharge port of the hydraulic pump is connected to each oil chamber of the cylinder via a check valve that blocks the flow of hydraulic oil in the inflow direction, and each oil chamber of the cylinder is connected to a tank via a counter valve. Each counter valve is opened by each discharge side pilot pressure of the hydraulic pump so that the hydraulic oil discharged from the cylinder always returns to the tank during operation. And the like are prevented from staying, and deterioration of function and performance can be suppressed.

[Brief description of drawings]

FIG. 1 is a hydraulic circuit diagram for explaining an up operation of a power tilt / trim device to which the present invention is applied.

FIG. 2 is a hydraulic circuit diagram for explaining a down operation of the device.

FIG. 3 is a hydraulic circuit diagram of a conventional power tilt / trim device.

[Explanation of Codes] 1 ... Tilt cylinder, 2 ... Trim cylinder, 12 ... Hydraulic pump, 14 ... Filter, 15 ... Tank, 16 ... First check valve, 17 ... Second check valve, 18 ... Relief valve, 19 ... 3rd check valve, 21 ... 1st filter, 22 ... 1st counter valve, 23 ... 2nd filter, 24 ... 2nd counter valve.

Claims (2)

[Claims] 1. A reversible hydraulic pump capable of sucking hydraulic oil from a tank through a filter and discharging the hydraulic oil from first and second ports, and a hydraulic pressure driven by the hydraulic oil discharged from each port of the hydraulic pump. In a power tilt / trim device such as an outboard motor provided with a cylinder, each discharge port of the hydraulic pump is connected to each oil chamber of the cylinder via a check valve that blocks the flow of hydraulic oil in the inflow direction. Each oil chamber of the cylinder is connected to the tank via a counter valve, and each counter valve is opened by each discharge side pilot pressure of the hydraulic pump. Hydraulic circuit. 2. The reverse cylinder for permitting only the flow of hydraulic fluid from the trim cylinder side to the tilt cylinder side between the upper chamber of the tilt cylinder and the upper chamber of the trim cylinder. The valve is connected via a stop valve, and the hydraulic pump and the upper chamber of the trim cylinder are connected via a relief valve that opens when the discharge pressure exceeds a predetermined value. Hydraulic circuit for the described power tilt / trim device.