JP2925950B2 - Automatic control device for road rollers - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic control apparatus for a road roller used for compacting a roadbed or a pavement surface. More specifically, the present invention relates to a method for automatically stopping an engine when a road roller is working on a slope such as a slope. The present invention relates to an automatic control device for preventing an abnormal situation in which a roller rolls into an uncontrollable state due to the cause of the above.

[0002]

2. Description of the Related Art Conventionally, a road roller used for compaction of a roadbed or the like, as a running means of the roller, drives a hydraulic pump by the power of an engine mounted on an airframe to generate fluid energy, and the fluid energy is transmitted to a front wheel. A system is used in which the motors are supplied to hydraulic motors provided respectively for the rollers and the rear wheel rollers, and the front and rear wheel rollers are rotationally driven by the respective hydraulic motors.

[0003] As the load roller driven by the hydraulic motor, a large roller in which an operator rides on the machine to operate the vehicle, and a worker who walks on the machine without walking on the machine without walking on the machine. There is a hand-guided small roller that operates a handle that protrudes from the hand.

In the case of the above-mentioned large rollers, a large engine that can be started by a starter motor is used. Therefore, even if the engine and the hydraulic pump are directly connected by a coupling, a starting force can be directly applied to the engine. However, in the case of a hand-guided small roller, a small engine that starts with a crank bundle or recoil starter is used, so if the hydraulic pump is directly connected to the engine, the hydraulic pump becomes a load and it is difficult to start the engine Therefore, a centrifugal clutch is provided between the engine and the hydraulic pump so that the starting torque of the engine is not transmitted to the hydraulic pump, and after the engine starts and reaches a predetermined number of revolutions, the rotation is transmitted via the centrifugal clutch. To the hydraulic pump.

[0005]

However, in such a load roller, since the driving force of a hydraulic motor is used as a driving source of the roller, during a work on a slope such as a sloping road, there is some cause, for example, If the connection between the input shaft of the hydraulic pump and the output shaft of the engine is broken and the hydraulic pump suddenly goes into a free state without receiving the power of the engine, the weight of the roller causes the hydraulic motor to In operation, hydraulic oil is pumped in the opposite direction from the hydraulic motor to the hydraulic pump, causing the hydraulic pump to rotate, and this may cause an accident that the aircraft may run away as if it rolls down an inclined ground. is there.

The above-mentioned abnormal situation may be caused by a large roller that directly connects the engine and the hydraulic pump by a coupling, when the coupling is damaged, or when the engine and the hydraulic pump are connected by a belt. In some cases, it occurs when the belt is cut or detached, or when the piping of the traveling system is damaged.

Further, in the case of a small roller having a centrifugal clutch provided between the engine and the hydraulic pump, the centrifugal clutch does not work because the engine stalls during work traveling on a slope or when the engine speed is reduced during traveling. This occurs when power cannot be transmitted due to a failure of the centrifugal clutch, or when the vehicle is parked on a slope. In addition, in the case of a large roller or a small roller, a similar runaway occurs when the hydraulic pump cannot control the body due to some abnormality.

[0008] Of course, in the case of a large roller or a small roller, the body is provided with a brake device. Therefore, when an abnormal situation occurs due to the above-described cause, the brake device may be operated. In particular, in the case of a small roller, since the worker walks from behind the roller, it may not be possible to operate the brake device immediately when an abnormal situation occurs. If it does not operate, the runaway as described above may not be avoided.

[0009]

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned problems in the conventional load roller.
When the hydraulic pump suddenly goes into a free state without receiving the power of the engine due to some cause of failure and the hydraulic oil flows backward from the hydraulic motor toward the hydraulic pump, the hydraulic oil It is an object of the present invention to provide an automatic control device that prevents backflow in the direction of a pump, prevents free rotation of a hydraulic motor, and prevents runaway on a slope.

According to a first aspect of the present invention, in a load roller driven by a hydraulic motor rotated by hydraulic oil from a hydraulic pump, hydraulic circuits 8, 9 for connecting the hydraulic pump 7 and the hydraulic motor 2 are provided with hydraulic pressure. Pilot circuit 1 for pump 7
7. The circuit is opened by pressure oil of a predetermined pressure by the pressure circuit 7, and closed by the pressure oil by the pilot circuit 17 falling below the predetermined pressure.
Shut-off switching valve 1 including flow path 14 and cutoff path 15
3 is provided.

[0011] The invention of claim 2 is the same as that of
A hydraulic circuit 8 for connecting the roller 1 with the hydraulic motor 2;
The hydraulic circuit 9 includes a pilot circuit 1 on the hydraulic pump 7 side.
7. The circuit is opened by pressure oil of a predetermined pressure by the
The circuit closes when the pressure oil by 17 drops below the predetermined pressure
It is characterized in that the shut-off switching valve 13 is connected to the cutoff path 15 side .

A third aspect of the present invention provides a hydraulic pump 7 and a front wheel rotor.
A hydraulic circuit 8 for connecting the hydraulic motor 2a of the roller 1a to the hydraulic circuit 2a;
The hydraulic pump 7 and the hydraulic motor 2b of the rear wheel roller 1b;
And a hydraulic circuit 9 connecting the hydraulic motor 2a and the hydraulic
A connecting circuit 19 is provided to the motor 2b to connect the motor 2b by a series circuit.
The pilot circuit on the hydraulic pump 7 side is connected to the connection circuit 19.
The circuit is opened by a predetermined pressure oil by the circuit 17, and the pilot
Closed when the pressure oil by the
The shut-off switching valve 13 is connected to the shut-off path 15 side .

The invention according to claim 4 is characterized in that the hydraulic pump 7 and the front wheel rotor
Hydraulic motor 2a of roller 1a and hydraulic pressure of rear wheel roller 1b
A hydraulic circuit 8 for connecting the motor 2b, a hydraulic pump 7 and
Of the hydraulic motor 2a of the wheel roller 1a and the rear wheel roller 1b.
A hydraulic circuit 9 connecting the hydraulic motor 2b and a hydraulic circuit 9
And the hydraulic circuit 8 and the hydraulic circuit 9 are respectively opened by hydraulic oil of a predetermined pressure by the pilot circuit 17 on the hydraulic pump 7 side, and the hydraulic oil by the pilot circuit 17 drops below the predetermined pressure. Shut-off switching valve 1
3 is connected to the cutoff path 15 side.

[0014]

During normal running, when the hydraulic pump 7 is driven, the hydraulic oil of a predetermined pressure sent through the pilot circuit 17 on the hydraulic pump side is sent to the switching valve 13 provided in the hydraulic circuit 8. Since the switching valve 13 is opened to the flow path 14 side, the pressure oil sent from the hydraulic pump 7 through one hydraulic circuit 8 rotates the hydraulic motor 2 and then passes through the other hydraulic circuit 9. Return to the hydraulic pump 7 .

As described above, during the operation of the road roller on a slope such as a hill, the hydraulic pump 7 suddenly goes into a free state without receiving the power of the engine due to some cause of failure, or 7, the hydraulic motor 2 operates as a pump by the weight of the roller, and until then, the hydraulic pump 8 is operated by one hydraulic circuit 8 .
The pressure oil flowing from the hydraulic motor 2 to the hydraulic motor 2 flows back from the hydraulic motor 2 to the hydraulic pump 7 , so that the aircraft starts to run away as if it rolls down on an inclined ground.

According to the present invention, when such an abnormal situation occurs, the hydraulic pump 7 is in a free state without receiving the power of the engine, or the hydraulic pump 7 decreases in pressure, and Since the pressure of the pressure oil that maintains the switching valve 13 in the open state through the pilot circuit 17 on the 7 side drops rapidly below a predetermined pressure, the switching valve 13 is automatically switched to the closed state by a spring. As a result, the hydraulic pump 7 passes through the hydraulic circuit 9 from the hydraulic motor 2.
The flow of pressure oil in the direction is immediately blocked and the hydraulic motor
Since the rotation of No. 2 is prevented, it is possible to reliably control a runaway in which the aircraft rolls down on an inclined ground.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows an automatic control device provided in a hand-guided small load roller for applying a driving force by a hydraulic motor 2 to only one roller 1. 3 is an engine, and 4 is a hydraulic pump device. The rotation of the engine 3 is provided with a swash plate 6 of the hydraulic pump device 4 via a transmission mechanism 5 such as a centrifugal clutch or a coupling. The information is transmitted to the hydraulic pump 7.

The hydraulic pump device 4 includes a hydraulic pump 7
A hydraulic circuit 8 connected from the port A to the hydraulic motor 2 and a hydraulic circuit 9 connected from the port B of the hydraulic pump 7 to the hydraulic motor 2. A swash plate type variable piston pump having a relief valve 11 and a check valve 12 between the hydraulic circuit 8 and the hydraulic circuit 9 is provided together with a pump 10.

When the roller 1 is moved forward, the hydraulic oil is sent from the port A of the hydraulic pump 7 to the hydraulic motor 2 of the roller 1 through the hydraulic circuit 8 by operating the swash plate 6 of the hydraulic pump 7. Is rotated in the forward direction, and then returned to the port B of the hydraulic pump 7 via the hydraulic circuit 9. When the roller 1 is to travel backward, the swash plate 6 of the hydraulic pump 7 is switched to send pressure oil from the port B of the hydraulic pump 7 to the hydraulic motor 2 of the roller 1 via the hydraulic circuit 9, and the hydraulic motor 2 After rotating in the reverse direction, the hydraulic pump 7
Back to port A.

The hydraulic circuit 8 for connecting the port A of the hydraulic pump 7 to the hydraulic motor 2 and the hydraulic circuit 9 for connecting the hydraulic motor 2 to the port B of the hydraulic pump 7 are provided in parallel with the hydraulic pump 7, respectively. A flow path 14 is opened by pressure oil of a predetermined pressure from a pilot circuit 17 connected to an auxiliary pump 10 such as a charge pump, and is closed when the pressure oil by the pilot circuit 17 falls below a predetermined pressure.
And a shut-off switching valve 13 comprising a shut-off path 15.

The shutoff switching valve 13 has a spring 16 on the shutoff path 15 side, and the pilot circuit 17 is connected on the flowpath 14 side, so that the engine 3 or the hydraulic pump 7 does not rotate, or When the pressure of the hydraulic oil sent from the pilot circuit 17 connected to the charge pump 10 decreases to a predetermined value or less due to the state of the output decrease, the shutoff path 15 is moved by the force of the spring 16 to the hydraulic circuits 8 and 9 The flow of the hydraulic oil in the hydraulic circuit 8 and the hydraulic circuit 9 is interrupted by the shutoff path 15 of the switching valve 13.

When the engine 3 is started and the hydraulic pump 7 is rotated in the forward direction, the hydraulic oil from the hydraulic pump 7 is sent to the hydraulic motor 2 through the hydraulic circuit 8, but at the same time, the charge pump 10 The pressure oil from the connected pilot circuit 17 is supplied to the flow path 14 of the shut-off switching valve 13 at a predetermined pressure.
The spring 16 is pushed down by this pilot pressure, and the flow path 14 is electrically connected to the hydraulic circuit 8 and the hydraulic circuit 9. The hydraulic oil from the hydraulic pump 7 rotates the hydraulic motor 2 from the hydraulic circuit 8. The circulation returning to the hydraulic pump 7 through the hydraulic circuit 9 is repeated.

Due to the above-described circulation of the pressure oil, when the roller 1 is traveling forward along the uphill, the hydraulic pump 7 becomes free due to a failure of the engine 3 or the transmission mechanism 6 in the middle of the uphill. Or, when the output decreases, as described above, the supply of the pressure oil in the direction of the hydraulic motor 2 stops, and the predetermined value of the pilot pressure from the charge pump 10 to the shut-off switching valve 13 decreases. , The shut-off switching valve 13 is
Is switched to the cutoff path 15 by the force, the flow of the hydraulic oil in the hydraulic circuit 8 and the hydraulic circuit 9 is stopped, and the rotation of the hydraulic motor is prevented.

In the above-described embodiment, the charge pump 10 is used as an accessory pump for sending pressure oil to the switching valve 13 of the hydraulic circuit through the pilot circuit 17.
The accessory pump is not necessarily limited to the charge pump, and may be a vibration hydraulic pump for applying vibration to the roller 1 or a hydraulic pump used for steering operation.

FIG. 2 shows a front wheel roller 1a and a rear wheel roller 1b.
This is an example of a load roller having hydraulic motors 2a and 2b on respective rollers. In this case, the hydraulic motor 2a of the front wheel roller 1a and the hydraulic motor 2b of the rear wheel roller 1b are connected by a connection circuit 19, and the hydraulic pump 7
Hydraulic circuit 8 for connecting the hydraulic motor 2a for the front wheel roller 1a to the hydraulic motor 2 for the hydraulic pump 7 and the rear wheel roller 1b.
b and a hydraulic circuit 9 that connects them with a series circuit,
One shut-off switching valve 13 is connected to the connection circuit 19.

FIG. 3 also shows a front wheel roller 1a and a rear wheel roller 1b, each of which has a hydraulic motor 2a.
In this case, the hydraulic pump 7 and the hydraulic motor 2 of the front wheel roller 1a are provided.
a and a hydraulic circuit 8 for the rear wheel roller 1b, and a hydraulic circuit 9 for the hydraulic pump 7 and the hydraulic motor 2a for the front wheel roller 1a and the hydraulic motor 2b for the rear wheel roller 1b. The hydraulic circuit 8 and the hydraulic circuit 9 are connected to the pair of shut-off switching valves 13 to form a parallel circuit.

[0027]

As described above, according to the present invention, the hydraulic circuit that connects the hydraulic pump and the hydraulic motor of the roller receives a predetermined pilot pressure from the pilot circuit on the hydraulic pump side to open the hydraulic circuit. Since the switching valve for closing the hydraulic circuit is connected when the pilot pressure falls below a predetermined value, the supply of hydraulic oil from the hydraulic pump is stopped due to a failure on the hydraulic pump side during work traveling on a slope. If the pilot pressure on the hydraulic pump side drops below a predetermined value due to a sudden drop in pressure, the switching valve of the hydraulic circuit will automatically switch to the closed side and immediately stop the rotation of the hydraulic motor. As a result, it is possible to prevent the danger caused by a runaway accident in which the aircraft rolls down along a slope, and to expect work safety.

Also, in this device, the switching valve of the hydraulic circuit is immediately switched to the closed side when the pilot pressure on the hydraulic pump side falls below a predetermined value, so that the pressure oil flowing in the direction of the hydraulic pump through the hydraulic circuit can be quickly reduced. In addition, the rotation of the hydraulic motor can be stopped instantaneously by properly shutting off. Further, the stop state is continued as long as the hydraulic pump side applies a predetermined pilot pressure to the switching valve and operates the switching valve to the open circuit side, so that safety accompanying stopping of the aircraft can be secured, A reliable danger prevention device can be provided.

[Brief description of the drawings]

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

FIG. 2 is a hydraulic circuit diagram showing another embodiment.

FIG. 3 is a hydraulic circuit diagram showing still another embodiment.

[Explanation of symbols]

1, 1a, 1b: Roller 2, 2a, 2b: Hydraulic motor 3: Engine 4: Hydraulic pump device 5: Transmission mechanism 6: Swash plate 7: Hydraulic pump 8, 9: Hydraulic circuit 10: Charge pump 13: Shut-off switching Valve 14: Flow path 15: Shutoff path 16: Spring 17: Pilot circuit 19: Connection circuit

Claims (4)

(57) [Claims] In a load roller driven by a hydraulic motor rotated by hydraulic oil from a hydraulic pump, hydraulic circuits connecting a hydraulic pump and a hydraulic motor are provided.
The flow path 14 is opened by hydraulic oil of a predetermined pressure by the pilot circuit 17 on the hydraulic pump 7 side, and is closed when the hydraulic oil by the pilot circuit 17 drops below the predetermined pressure.
An automatic control device for a load roller including a shut-off switching valve 13 including a path 15 . 2. A hydraulic pump comprising a hydraulic pump 7 and one roller 1.
The hydraulic circuit 8 and the hydraulic circuit 9 connecting the
The predetermined pressure is controlled by the pilot circuit 17 on the hydraulic pump 7 side.
The circuit is opened by the pressure oil, and the pressure oil by the pilot circuit 17
Shut-off switching that closes when the pressure drops below a certain level
2. The automatic control apparatus for a load roller according to claim 1, wherein the valve is connected to the shutoff path of the valve . 3. A hydraulic motor for the hydraulic pump 7 and the front wheel roller 1a.
Hydraulic circuit 8 for connecting the hydraulic pump 7
And a hydraulic circuit connecting the hydraulic motor 2b of the rear wheel roller 1b.
The path 9 is connected to the hydraulic motor 2a and the hydraulic motor 2b.
A connection circuit 19 is provided and connected by a series circuit.
The location of the pilot circuit 17 on the hydraulic pump 7 side
The circuit is opened by the constant pressure oil, and the pilot circuit 17
Shut-off that closes when the pressure oil drops below the specified pressure
2. The automatic control apparatus for a load roller according to claim 1, wherein the cutoff path side of the switching valve is connected . 4. A hydraulic pump between the hydraulic pump 7 and the front wheel roller 1a.
Motor 2b and the hydraulic motor 2b of the rear wheel roller 1b are connected.
Hydraulic circuit 8, the hydraulic pump 7, and the oil of the front wheel roller 1a.
Pressure motor 2a and hydraulic motor 2b of rear wheel roller 1b
And a hydraulic circuit 9 that connects the
A shut-off switching valve that opens to the pressure circuit 8 and the hydraulic circuit 9 with hydraulic oil of a predetermined pressure by a pilot circuit 17 on the hydraulic pump 7 side, and closes when the hydraulic oil by the pilot circuit 17 drops below a predetermined pressure. 3. The automatic control apparatus for a load roller according to claim 1, wherein the cut-off path side of the load roller is connected.