JP2596081Y2 - Hydraulic suspension device - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic suspension system for a vehicle such as a crane truck, and more particularly to a technique for ensuring safety when a vehicle such as a bridge passes through the vehicle.

[0002]

2. Description of the Related Art Conventionally, as a hydraulic suspension device for a vehicle such as a crane truck, there is one disclosed in Japanese Utility Model Application Laid-Open No. 63-148508 and Japanese Utility Model Application No. 3-106901 proposed by the present applicant. Such a hydraulic suspension device controls a hydraulic pressure supplied from a hydraulic supply source through a hydraulic control circuit to a hydraulic suspension hydraulic cylinder provided on each shaft to control a vehicle height to a set value. It has control means.

[0003]

By the way, multi-axle vehicles such as large crane vehicles are heavy, and therefore, on public roads, it is common to run only on a bogie whose crane portion is disassembled and removed. However, in the conventional hydraulic suspension system, the distribution of the axle weight of each shaft is set to be approximately equal. Therefore, when the weight of the bogie is heavy, it exceeds the safety standard (vehicle restriction order) when traveling on a bridge or the like. There is a problem in terms of safety.

The present invention has been made in view of the above, and an object of the present invention is to optimize the balance of axle weight in a hydraulic suspension device of a multi-axle vehicle by controlling the hydraulic pressure of an intermediate shaft.

[0005]

SUMMARY OF THE INVENTION The present invention controls the hydraulic pressure supplied from a hydraulic supply source via a hydraulic control circuit to hydraulic cylinders for hydraulic suspension provided on each shaft of a multi-axle vehicle. In a hydraulic suspension device having hydraulic control means for controlling a vehicle height to a set value, a hydraulic control circuit of a hydraulic cylinder of an intermediate shaft is provided with a pressure reducing valve and an opening / closing control valve in that order. A circuit is connected, and the hydraulic pressure of the hydraulic cylinder for the intermediate shaft is reduced by a pressure reducing valve so as to be lower than the hydraulic pressures of the hydraulic cylinders for the other shafts.

[0006]

When the opening and closing control valve is closed on the intermediate shaft,
The oil pressure from the oil pressure supply source is reduced in pressure by the pressure reducing valve, and is supplied to the upper oil chamber of the hydraulic cylinder for the intermediate shaft via the opening / closing control valve. In this way, the oil pressure of the hydraulic cylinder of the intermediate shaft is reduced by the pressure reducing valve, and the oil pressure of the hydraulic cylinder for the other shafts is made lower than that of the hydraulic cylinders for the other shafts. The weight distribution is controlled, and safety can be ensured when passing a bridge or the like with a bogie.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to the drawings. In FIG. 1, the hydraulic suspension structure for the left axis will be described.
The upper oil chamber a of each of the hydraulic cylinders 1 and 2 is supported by a first hydraulic cylinder 1 and a second hydraulic cylinder 2, respectively.
Is connected to an accumulator 8 via a lock valve 7 by a hydraulic circuit 9 to form a spring. Similarly, the third shaft and the fourth shaft which are intermediate shafts are respectively connected to the third hydraulic cylinder 3
The upper oil chamber a of each of the hydraulic cylinders 3 and 4 is connected to an accumulator 11 via a lock valve 10 by a hydraulic circuit 12 to form a spring. Further, similarly, the fifth axis and the sixth axis are
The upper hydraulic chamber a of each of the hydraulic cylinders 5 and 6 is supported by a fifth hydraulic cylinder 5 and a sixth hydraulic cylinder 6, respectively.
Is connected to an accumulator 14 via a lock valve 13 by a hydraulic circuit 15 to form a spring.

On the other hand, the hydraulic pressure supplied to the hydraulic cylinders 1 and 2, 3 and 4, 5 and 6 from an oil tank 16 serving as a hydraulic supply source via a hydraulic control circuit is controlled, and the vehicle height is controlled. Are set to a set value. That is, a forward hydraulic control circuit 19 provided with a hydraulic supply switching valve 18 is connected to an oil pump 17 connected to the oil tank 16, and the hydraulic control circuit 19 branches off in the middle. One branch circuit 19a includes a first axis and a second axis.
It is connected to the hydraulic circuit 9 between the lock valve 7 and the hydraulic cylinders 1 and 2 via the charge valve 20 in the hydraulic control means A of the shaft. The other branch circuit 19b is connected to the fifth branch circuit 19b.
Valve in the hydraulic control means C of the shaft and the sixth shaft
1 is connected to a hydraulic circuit 15 between the lock valve 13 and the hydraulic cylinders 5 and 6.

The filter 22 communicated with the oil tank 16
Is connected to a return-side hydraulic control circuit 23, and the hydraulic control circuit 23 branches on the way. One branch circuit 23a is connected to the drain valve 2 in the hydraulic control means A for the first axis and the second axis.
4 is connected to a hydraulic circuit 9 between the lock valve 7 and the hydraulic cylinders 1 and 2. Also, the other branch circuit 23b
Are connected to the lock valve 13 and the hydraulic cylinder 5 through the drain valve 25 in the hydraulic control means C of the fifth and sixth axes.
6 is connected to the hydraulic circuit 15.

A hydraulic control circuit 19c branched from the downstream side of the hydraulic supply switching valve 18 of the forward hydraulic control circuit 19
Pressure reducing valve 30 and intermediate shaft circuit shut-off valve 26 as an open / close connection valve in hydraulic control means B of the third and fourth shafts
Through the lock valve 10 and the hydraulic cylinders 3 and 4
Is connected to the hydraulic circuit 12. Also, the fifth axis and the sixth axis
A hydraulic control circuit 15a branched from the hydraulic circuit 15 between the lock valve 13 of the shaft and the hydraulic cylinders 5, 6 is connected via a connection valve 27 as an open / close connection valve in the hydraulic control means B of the third and fourth shafts. Connected to the hydraulic circuit 12 between the lock valve 10 and the hydraulic cylinders 3 and 4.

Here, the first and second hydraulic cylinders 1 and 6 are provided with two high-side and low-side vehicles for detecting the oil position in the upper oil chamber a and detecting the vehicle height. Height sensor 28,
29 are provided respectively. The opening and closing of the charge valves 20, 21 and the drain valves 24, 25 are controlled based on the signals from the vehicle height sensors 28, 29, and the vehicle height is controlled to a set value.

Next, the operation of the hydraulic suspension device having the above configuration will be described. When the vehicle height is neutralized in a state where the crane is disassembled and removed, the hydraulic supply switching valve 18 is turned on to open. The first and second axes, and the fifth and sixth axes have vehicle height sensors 28 and 2 respectively.
9, the oil pressure from the oil tank 16 is
Control supplied to the upper oil chambers a of the hydraulic cylinders 1, 2, 5 and 6 via the charge valves 20, 21 opened and turned on, and the drain valve 24 opened
The control is performed such that the hydraulic pressure in the upper oil chambers a of the hydraulic cylinders 1, 2, 5 and 6 is returned to the oil tank 16 via the hydraulic cylinder 25, and the pistons b of the hydraulic cylinders 1, 2 and 5 and 6 The vehicle height is adjusted to the set value so as to be located between 28 and 29.

In the above operation, when the intermediate shaft circuit shut-off valve 26 is turned on and opened and the connection valve 27 is turned off and closed on the third and fourth shafts, the oil pressure from the oil tank 16 is reduced by the pressure reducing valve 30. , And is supplied to the upper oil chambers a of the hydraulic cylinders 3 and 4 via the intermediate shaft circuit shut-off valve 26 which is turned ON and opened. in this way,
The hydraulic pressure of the hydraulic cylinders 3 and 4 for the third and fourth shafts as intermediate shafts is reduced by the pressure reducing valve 30, and the hydraulic cylinders 1 for the other first and second shafts, the fifth and sixth shafts are reduced. , 2, 5 and 6, the distribution of axle load is controlled such that the axle load distribution is less for the intermediate shaft and the other shafts are heavier.

After the vehicle height is adjusted to the set value as described above, the lock valves 7, 10, 13 are turned on to maintain the open state, and the charge valves 20, 21, the drain valves 24, 25 and the intermediate If the shaft circuit cutoff valve 26 and the connection valve 27 are turned off and closed, the truck can travel.
When the crane portion is mounted on the bogie, when the intermediate shaft circuit shut-off valve 26 is turned off and closed, and the connecting valve 27 is turned on and opened, the hydraulic pressures of the fifth and sixth shaft hydraulic cylinders 5, 6 are increased. At the same time as the oil supply to the upper oil chamber a of the third and fourth shaft hydraulic cylinders 3 and 4 via the connection valve 27, At the same time that the oil pressure in the oil chamber a is returned to the oil tank 16, the control is such that the oil pressure in the upper oil chamber a of the hydraulic cylinders 3, 4 of the third and fourth shafts is returned to the oil tank 16 via the connection valve 27. Is performed, and the vehicle height is adjusted to the set value.

According to the hydraulic suspension system having such a configuration, as described above, the hydraulic pressure of the intermediate shaft hydraulic cylinders 3, 4 is reduced by the pressure reducing valve 30, and the hydraulic cylinders 1, 2, and 5 for the other shafts are reduced. As a result, the distribution of the axle load is controlled so that the middle shaft is less and the other shafts are heavier, so that the safety of the truck when passing through a bridge or the like can be secured. When the crane portion is mounted on the bogie, the hydraulic pressure of the hydraulic cylinders 3 and 4 for the intermediate shaft can be made equal to the hydraulic pressures of the hydraulic cylinders 1, 2 and 5 and 6 for the other shafts. The distribution of the shaft weight of the shaft can be set substantially uniformly.

As described above, the present invention has been described with reference to the specific embodiment. However, the present invention is not limited to this, and is attached to the present invention by a person skilled in the art. It should be noted that various changes and modifications can be made without departing from the scope of the utility model registration claims.

[0017]

According to the present invention, as described above, the pressure control circuit of the hydraulic cylinder of the intermediate shaft is connected to the pressure reduction circuit from the hydraulic supply source in which the pressure reduction valve and the opening / closing control valve are respectively interposed. Since the hydraulic pressure of the hydraulic cylinder for the intermediate shaft is reduced by the pressure reducing valve so as to be lower than the hydraulic pressure of the hydraulic cylinder for the other shafts, the distribution of axle weight is such that the intermediate shaft is less and the other shafts are heavier. Thus, the distribution of axle load can be controlled, and the practical effect of securing safety when passing a bridge or the like with a bogie can be increased.

[Brief description of the drawings]

FIG. 1 is a hydraulic circuit diagram showing an embodiment of a hydraulic suspension device according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 1st hydraulic cylinder 2 2nd hydraulic cylinder 3 3rd hydraulic cylinder 4 4th hydraulic cylinder 5 5th hydraulic cylinder 6 6th hydraulic cylinder 16 oil tank A-C Hydraulic control means 26 Intermediate shaft circuit cutoff Valve 27 Connecting valve 30 Pressure reducing valve

Claims (1)

(57) [Scope of request for utility model registration] A vehicle height is controlled to a set value by controlling a hydraulic pressure supplied from a hydraulic supply source via a hydraulic control circuit to each of hydraulic cylinders for a hydraulic suspension provided on each shaft of a multi-axle vehicle. In a hydraulic suspension device having a hydraulic control means for controlling, a pressure reduction circuit from the hydraulic supply source, in which a pressure reducing valve and an opening / closing control valve are interposed in this order, is connected to a hydraulic control circuit of a hydraulic cylinder of the intermediate shaft, A hydraulic suspension device characterized in that the hydraulic pressure of a hydraulic cylinder for a hydraulic cylinder is reduced by a pressure reducing valve so as to be lower than the hydraulic pressures of hydraulic cylinders for other shafts.