JPH0318320Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a hydraulic steering system, and more particularly to a hydraulic steering system with an improved stopping mechanism at the maximum rudder angle.

As a conventional hydraulic steering device, there is one as shown in Fig. 1. When a steering signal is generated from the wheelhouse, the power cylinder 3 as a steering control mechanism is controlled by the steering signal to a specified steering angle. It is designed to be displaced by an amount corresponding to .

The displacement of the power cylinder 3 is transmitted to the discharge control section 11 of the main pump 6 by a follow-up mechanism 4 consisting of a link mechanism, and the main pump 6 steers the displacement according to the control amount of the discharge control section 11. By supplying pressure oil to the hydraulic piston 5 in the machine 16, the rudder 10 begins to change its rudder angle.

Changes in the rudder angle of the rudder 10 are transmitted to the discharge control section 11 via the follow-up mechanism 4, and gradually
When the displacement of the power cylinder 3 and the rudder angle of the rudder 10 correspond to each other by decreasing the control amount of the discharge control part 1
The control amount of 1 completely disappears.

As a rudder stopping mechanism in such a conventional steering device, a stopper 1 of the power cylinder 3 is used.
a, 1b, and mechanical stoppers 2a, 2b, 2c, 2d of the steering gear 16, for example,
Assuming that the maximum steering angle that the rudder 10 can take is 37 degrees, the stops 1a and 1b of the power cylinder 3 as a steering control mechanism are adjusted to 36.5 degrees, and the mechanical stops 2a and 2b of the steering gear are adjusted to 36.5 degrees.
2c and 2d were adjusted to 37 degrees.

By the way, in such a conventional rudder stopping mechanism, there is a problem that if there is play in the following mechanism 4, the rudder angle exceeds the maximum rudder angle adjusted by the power cylinder 3 (flow rudder).

In addition, the mechanical stopper 2 of the steering gear 16
Since the steering wheels a, 2b, 2c, and 2d stop the rudder at the portions that receive the entire thrust of the hydraulic piston 5, there is a problem in that the impact applied to the steering gear becomes large and damages the steering gear.

The present invention is an attempt to solve the above-mentioned problems in conventional hydraulic steering devices. It is an object of the present invention to provide a hydraulic steering device which is capable of stopping without exceeding the angular limit and without causing a shock, and which is also capable of pulling back the rudder which is in a stopped state at the maximum rudder angle position. do.

Therefore, the hydraulic steering system of the present invention has a main pump that is controlled via a follow-up mechanism according to the control amount from the steering control mechanism, and a main pump that can supply pressure oil from the main pump to the hydraulic steering gear. It is equipped with a hydraulic line and a pilot hydraulic line that can shut off the main hydraulic line by operating a transfer valve installed in the main hydraulic line, and detects the limit point of displacement in both left and right directions in the above-mentioned steering control mechanism. a pair of first limit switches for detecting the operating amount of the steering gear in both left and right directions;
Only when detection signals from either one of the pair of first limit switches and the second limit switch are received, the pilot hydraulic pressure in the pilot hydraulic line is used to move the transfer valve in the main hydraulic line. The invention is characterized in that a solenoid valve for switching the pilot hydraulic line is connected to the pilot hydraulic line in order to forcefully operate the pilot hydraulic line.

A hydraulic steering system as an embodiment of the present invention will be described below with reference to the drawings. FIG. 2 is a schematic diagram including a follow-up mechanism thereof, and FIG. 3 is a hydraulic system diagram thereof.

As shown in FIGS. 2 and 3, in the case of this embodiment as well, the main pump is pumped through the follow-up mechanism 4 in accordance with the control amount from the steering control mechanism including the power cylinder 3, as in the conventional system described above. 6 is adapted to be controlled, and a pair of main hydraulic lines 18, 18 including a reserve are provided so that pressure oil can be supplied from the main pump 6 to the hydraulic piston 5 of the hydraulic steering gear 16.
A transfer valve 15 is interposed in each main hydraulic line 18.

In addition, by operating the transfer valve 15,
A pilot hydraulic line 19 is provided so that the main hydraulic line 18 can be shut off.

Limit switch operating pieces 13a, 13b are provided at both left and right ends of the power cylinder 3, and the limit switch operating pieces 13a, 13b are arranged so that the displacement of the power cylinder 3 reaches approximately 36.5 degrees in terms of steering angle. 1 limit switch 12a, 12b is operated.

Further, the rudder 10 is provided with a second limit switch 17 that directly detects the rudder angle and operates at a rudder angle of about 36.5 degrees.

Furthermore, a solenoid valve 14 is connected to the pilot hydraulic line 19 to switch the pilot hydraulic line 19 so as to forcibly operate the transfer valve 15 to the shutoff side of the main hydraulic line 18 using the pilot hydraulic pressure.

And the first limit switch 12a, 12
When one of the two limit switches b and the second limit switch 17 are activated and both of these detection signals are transmitted to the solenoid valve 14, the solenoid valve is switched, and the hydraulic pressure in the pilot hydraulic line 19 is thereby transferred to the transfer valve. 15 to the cutoff side of the main hydraulic line 18. In FIG. 2, numerals 2a, 2b, 2c, and 2d indicate mechanical stoppers in the steering gear 16, and numeral 11 indicates a discharge control section.

Further, in FIG. 3, reference numeral 7 indicates an auxiliary pump, and reference numeral 9 indicates a pilot relief valve.

Since the hydraulic steering system according to the present invention is configured as described above, the power cylinder 3 starts displacement in response to a steering signal from the wheelhouse, and the control amount as the displacement amount is sent to the main pump 6 via the follow-up mechanism 4. The main pump 6 is thereby controlled.
Pressure oil is then supplied from the main pump 6 to the hydraulic steering machine 16 through the main hydraulic line 18.
However, when the displacement of the power cylinder 3 corresponds to the maximum steering angle (approximately 36.5 degrees), either of the limit switch actuating pieces 13a, 13b works and the first limit switch 12a,
12b is activated. And rudder 10
When the steering angle reaches approximately 36.5 degrees, the second limit switch 17 provided on the steering gear 16 also operates.

In this way, the first limit switch 12
Only when either a or 12b and the second limit switch 17 are actuated, the solenoid valve 14 is energized and switched, thereby causing the pressure oil in the pilot hydraulic line 19 to force the transfer valve 15. When activated, the main hydraulic line 18 can be shut off to safely and reliably stop the movement of the rudder.

When moving (pulling back) the rudder 10 from the above-mentioned stopped state (stopped state at the maximum steering angle position), the power cylinder 3 moves in the opposite direction in response to a steering signal from the wheelhouse, 1 limit switch (12a or 12b) becomes inactive. As a result, the solenoid valve 14 also returns to its original state.

Therefore, the pilot hydraulic line 19 is switched again to operate the transfer valve 15 to the connection side of the main hydraulic line 18, and since the transfer valve 15 connects the main hydraulic line 18, steering can be performed without any trouble. It is possible.

As mentioned above, this hydraulic steering system includes first limit switches 12a and 12b that detect the limit point of the control amount of the power cylinder 3, and a second limit switch that detects the limit point of the operating amount of the steering gear 16. 17, the rudder 10 can be reliably stopped at the limit of the rudder angle via the solenoid valve 14, and even if the follow-up mechanism 4 has play, the rudder 10 will maintain the rudder angle. without exceeding the limit of mechanical stoppers 2a, 2.
This has the effect of being able to stop without causing impact at points b, 2c, and 2d.

Furthermore, in order to detect the limit point of the amount of displacement of the power cylinder 3 in both the left and right directions, a pair, that is, two first limit switches are provided. Since the rudder is configured to stop only when both the second limit switch that detects the rudder and the second limit switch are in the operating state, when the power cylinder moves in the return direction to pull back the rudder that is in the stopped state,
The stop of the rudder is immediately released and the rudder is pulled back.

As described in detail above, according to the hydraulic steering system of the present invention, the main pump is controlled via the follow-up mechanism according to the control amount from the steering control mechanism, and the main pump provides pressure to the hydraulic steering gear. It is equipped with a main hydraulic line that can supply oil and a pilot hydraulic line that can shut off the main hydraulic line by operating a transfer valve installed in this main hydraulic line. A pair of first limit switches that detect the limit point of the amount of operation, and a second limit switch that detects the limit point of the amount of operation in both left and right directions of the steering gear are provided, and one of the first limit switches of the pair The transfer valve is forcibly operated to the cutoff side of the main hydraulic line using the pilot hydraulic pressure of the pilot hydraulic line only when detection signals from one of the limit switches and the second limit switch are both received. It has a simple structure in which the solenoid valve that switches the pilot hydraulic line is connected to the pilot hydraulic line, which prevents the flow rudder caused by the backlash of the following mechanism, which was a problem in the past, and allows the rudder to be connected to the mechanical stopper of the steering gear. This has the advantage of being able to safely and reliably stop the rudder without causing an impact just before it hits the steering wheel, thereby preventing damage to the steering gear, and also being able to pull back the rudder that is stopped at the maximum rudder angle position.

[Brief explanation of drawings]

Fig. 1 is a schematic diagram showing a conventional hydraulic steering device, and Figs. 2 and 3 show a hydraulic steering device as an embodiment of the present invention, and Fig. 2 includes the following mechanism. Figure 3 is a diagram of its hydraulic system. 1a, 1b...stopper, 2a, 2b, 2
c, 2d...Mechanical stopper, 3...Power cylinder, 4...Following mechanism, 5...Hydraulic piston, 6...Main pump, 7...Auxiliary pump, 9...
Pilot relief valve, 10...Rudder, 11...Discharge control unit, 12a, 12b...First limit switch, 13a, 13b...Limit switch operating piece, 14...Solenoid valve, 15...Transfer valve, 16... ...Steering gear, 17...Second limit switch, 18...Main hydraulic line, 19...Pilot hydraulic line.

Claims (1)

[Scope of utility model registration request] A main pump that is controlled via a follow-up mechanism according to the control amount from the steering control mechanism, a main hydraulic line that can supply hydraulic pressure from the main pump to the hydraulic steering gear, and a main hydraulic line that is interposed in this main hydraulic line. a pair of first limit switches for detecting the limit points of displacement in both left and right directions in the steering control mechanism; a second limit switch for detecting the limit point of the operating amount in both the left and right directions of the machine, and receives detection signals from both the limit switch of one of the pair of first limit switches and the second limit switch. A solenoid valve for switching the pilot hydraulic line is connected to the pilot hydraulic line in order to forcibly operate the transfer valve to the cutoff side of the main hydraulic line using the pilot hydraulic pressure of the pilot hydraulic line. A hydraulic steering device characterized by: