JP2796942B2 - 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 in 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 hand-guided small rollers, 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 rotational force 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 performed 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 for some reason the hydraulic pump suddenly goes into a free state without receiving the power of the engine and the hydraulic oil is back-fed from the hydraulic motor to the hydraulic pump, It is an object of the present invention to provide an automatic control device capable of preventing back pressure of pressurized oil in a direction, preventing free rotation of a hydraulic motor, and preventing 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, a shutoff path and a throttle valve are respectively provided in a hydraulic circuit connecting the hydraulic pump and the hydraulic motor. And a pilot circuit is connected between the hydraulic motor side and the cutoff path in the hydraulic circuit.

According to a second aspect of the present invention, a hydraulic circuit for connecting a hydraulic pump and a hydraulic motor for a front wheel roller and a hydraulic circuit for connecting a hydraulic pump and a hydraulic motor for a rear wheel roller are provided with a hydraulic motor for a front wheel roller. A connection circuit is provided to the hydraulic motor of the rear wheel roller and connected by a serial circuit, and the respective hydraulic circuits are connected to the throttle valve side of a pair of fuse valves including a shutoff path and a throttle valve. A pilot circuit is connected between the hydraulic motor side and the cutoff path.

A third aspect of the present invention provides a hydraulic circuit for connecting a hydraulic pump to a hydraulic motor for a front wheel roller and a hydraulic motor for a rear wheel roller, and a hydraulic pump, a hydraulic motor for a front wheel roller and a hydraulic motor for a rear wheel roller. The hydraulic circuit to be connected is connected by a parallel circuit, and the respective hydraulic circuits are connected to the throttle valve side of a pair of fuse valves including a shutoff path and a throttle valve, and the hydraulic motor side and the shutoff path in the hydraulic circuit are connected. And a pilot circuit is connected between them.

[0013]

During normal traveling, the fuse valve provided in the hydraulic circuit connecting the hydraulic pump and the hydraulic motor is connected to the throttle valve side by a spring, so that the hydraulic oil sent from the hydraulic pump is supplied to one hydraulic circuit. , And then returns to the hydraulic pump through another hydraulic circuit.

As described above, if the hydraulic pump suddenly goes into a free state without receiving the power of the engine due to some failure while the road roller is working on a slope such as a slope, the hydraulic pressure is reduced by the weight of the roller. The motor acts as a pump, and the pressure oil, which had been flowing from the hydraulic pump to the hydraulic motor by one hydraulic circuit, is sent back from the hydraulic motor to the hydraulic pump. It starts to run away like falling down.

According to the present invention, when pressure oil is reversely fed from the hydraulic motor side to the hydraulic pump side due to the occurrence of such an abnormal situation, pressure oil having a flow rate equal to or greater than a set flow rate flows through the throttle valve from the reverse pressure feed path. As a result, a pressure difference is generated between the inlet side (hydraulic motor side) and the outlet side (hydraulic pump side) of the throttle valve, and the force acting on the pilot circuit provided on the hydraulic motor side is changed by the fuse valve. To the side of the cutoff path. As a result, the pressure oil flowing from the hydraulic motor side to the hydraulic pump side is blocked in the hydraulic circuit, and the rotation of the hydraulic motor is prevented, so that runaway in which the machine body rolls down on an inclined ground can be controlled.

[0016]

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 charge pump 10 is provided with the hydraulic pump 7. And the hydraulic circuit 8
Relief valve 11 and check valve 12 between
And a swash plate type variable piston pump having:

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 via 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.

A hydraulic circuit 8 for connecting the port A of the hydraulic pump 7 to the hydraulic motor 2 and a hydraulic circuit 9 for connecting the hydraulic motor 2 to the port B of the hydraulic pump 7 have a shutoff path 14 and a throttle valve 15, respectively. And a pair of fuse valves 1 having
3 are connected.

The fuse valves 13a and 13b are
The throttle valve 15 is always connected to the hydraulic circuit 8 and the hydraulic circuit 9 by a spring 16 so as to be electrically connected to each other, and a pilot valve is provided between the hydraulic pump 7 side of the hydraulic circuit 8 and the hydraulic circuit 9 and the throttle valve 15. Circuit 17
Is connected, and a pilot circuit 18 is connected between the hydraulic motor 2 side and the shutoff path 14.

The throttle valve 15 of the fuse valve 13 is
The hydraulic circuit 8 and the hydraulic circuit 9 are always connected to each other by a spring 16 so as to be electrically connected. However, since the pilot circuit 17 is connected between the hydraulic circuit 8 and the hydraulic pump 7, for example, In the case of forward running in which the oil flows to the hydraulic circuit 9, in addition to the pressing force of the spring 16, the pressure oil sent through the pilot circuit 17 of the fuse valve 13 is supplied to the hydraulic circuit 8 of the throttle valve 15.
Continuity is reliably maintained.

On the other hand, the fuse valve 13 of the hydraulic circuit 9
When a proper amount of pressure oil flows from the hydraulic motor 2 of the roller 1 toward the hydraulic pump 7 through the throttle valve 15, the throttle valve 15 is electrically connected to the hydraulic circuit 9 by the pressing force of the spring 16. Connected to the hydraulic pump 7
From the hydraulic circuit 8 rotates the hydraulic motor 2 and returns to the hydraulic pump 7 through the hydraulic circuit 9 to repeat the circulation.

If the hydraulic pump 7 becomes free due to an accident such as breakage of the transmission mechanism 5 in the middle of the hill while the roller 1 is moving forward along the uphill due to the above-described pressure oil circulation, When the supply of the pressure oil to the hydraulic motor 2 is cut off, the roller 1 starts to retreat by its own weight,
The hydraulic oil of the hydraulic motor 2 passes through the hydraulic circuit 8 and the hydraulic pump 7
Will flow back in the direction of.

When such an abnormal situation occurs, the hydraulic motor 2 operates as a hydraulic pump, and a large amount of pressure oil is sent back through the hydraulic circuit 8 to the throttle valve 15 of the fuse valve 13 in reverse pressure. Since the pressurized oil having a flow rate or more tries to pass through the throttle valve 15 at a time, a pressure difference occurs between the inlet side (the hydraulic motor 2 side) and the outlet side (the hydraulic pump 7 side) of the throttle valve 15, The force acting on the pilot circuit 18 provided on the hydraulic motor 2 side overcomes the force of the spring 16 and moves the fuse valve 13 to the shutoff path 14 side. As a result, the pressure oil flowing from the hydraulic motor 2 to the hydraulic pump 7 is blocked in the hydraulic circuit 8 and the rotation of the hydraulic motor 2 is prevented.

If, for example, the transmission mechanism 6 is broken in the middle of the hill while the roller 1 is traveling forward along the downhill, the roller 1 starts to move forward by its own weight as described above. In this case, a large amount of pressure oil is sent to the throttle valve 15 of the fuse valve 13 through the hydraulic circuit 9, and a part of the pressure oil flows from the pilot circuit 18 toward the shutoff path 14. Motor 2 to hydraulic circuit 9
The flow of the pressurized oil which is reversely fed in the direction of the hydraulic pump 7 is blocked.

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,
The pair of fuse valves 13 are respectively connected to the hydraulic circuit 8 and the hydraulic circuit 9.

FIG. 3 also has 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 connecting the hydraulic pump 7 to the hydraulic motor 2a for the front wheel roller 1a and the hydraulic motor 2b for the rear wheel roller 1b. The pair of fuse valves 13 are connected to the hydraulic circuit 8 and the hydraulic circuit 9 respectively.

[0028]

As described above, according to the present invention, the shutoff path 14 and the throttle valve 15 are provided in the hydraulic circuit 8 and the hydraulic circuit 9 for connecting the hydraulic pump 7 and the hydraulic motor 2 for the roller, respectively.
A pair of fuse valves 13 having
5 is connected to the hydraulic circuit 8 and the hydraulic circuit 9, so that a large amount of pressure oil flows in the direction from the hydraulic motor 2 to the hydraulic pump 7 due to an accident on the hydraulic pump side during work traveling on a slope. When the pressure oil is fed, a part of the pressure oil passing through the throttle valve 15 of the fuse valve 13 is switched from the pilot circuit 18 to the cutoff path 14 side, thereby blocking the flow of the pressure oil that is sent back to the hydraulic pump 7. The rotation of the hydraulic motor 2 is prevented.

According to the present invention, when a large amount of pressure oil is reversely fed to the throttle valve 15 of the fuse valve 13, a part of the flow of the pressure oil that cannot pass through the throttle valve 15 is caused to flow to the pilot circuit and cut off. Since the valve 13 is switched to the path 14 side, the rotation of the hydraulic motor 2 is stopped once by switching the valve 13 to the shutoff path 14 side. However, when the rotation of the hydraulic motor 2 is stopped, the flow of the pressure oil flowing in the direction of the fuse valve 13 is stopped. , The flow to the pilot circuit 18 also stops.
Switch to the 5 side.

As a result, the pressure oil flows again from the hydraulic motor 2 side through the throttle valve 15 of the fuse valve 13 to the hydraulic pump 7.
The roller 1 once stopped, starts to roll again, and this causes a large amount of pressure oil to pass through the throttle valve 15 of the fuse valve 13 again, thereby causing the valve 1 to rotate.
The roller 3 is switched to the cutoff path 14 again, so that the roller 1 stops again. As described above, the roller 1 repeatedly stops and runs. However, since such a movement can stop a continuous runaway state, the roller rolling mechanism can be operated by operating the roller brake mechanism during that time. Can be reliably stopped, and the occurrence of a runaway accident in which the aircraft rolls down along a slope can be reliably controlled.

Since the fuse valves 13 are provided in the hydraulic circuit 8 and the hydraulic circuit 9, respectively, the fuse valve 13 of the hydraulic circuit 8 is actuated in case of runaway in the rear of the body, and in case of runaway in front of the body. Can operate the fuse valve 13 of the hydraulic circuit 9 to cope with abnormal situations associated with each situation, and to prevent the occurrence of danger due to this kind of accident and to expect the safety of work. it can.

[Brief description of the drawings]

FIG. 1 is a hydraulic circuit diagram showing one embodiment of an abnormal rolling prevention 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 13: Fuse valve 14: Shutoff path 15 ： Throttle valve 17, 18 ： Pilot circuit 19 ： Connection circuit

Claims (3)

(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.
Are connected to the throttle valve 15 side of a pair of fuse valves 13 each including a shutoff path 14 and a throttle valve 15, and a pilot circuit is provided between the hydraulic motor 2 side and the shutoff path 14 in the hydraulic circuits 8 and 9. 18. An automatic control device for a load roller, wherein the control device 18 is connected. 2. A hydraulic circuit 8 for connecting the hydraulic pump 7 to the hydraulic motor 2a of the front wheel roller 1a, and a hydraulic circuit 9 for connecting the hydraulic pump 7 and the hydraulic motor 2b of the rear wheel roller 1b.
And the hydraulic motor 2a of the front wheel roller 1a and the rear wheel roller 1a.
The hydraulic circuit 2b is connected to the hydraulic motor 2b by a series circuit and connected to the hydraulic circuits 8 and 9 by a pair of fuse valves 13 each comprising a shutoff path 14 and a throttle valve 15.
2. The automatic control device for a load roller according to claim 1, wherein the throttle valve 15 side is connected, and a pilot circuit 18 is connected between the hydraulic motors 2 a, 2 b side and the shutoff path 14 in the hydraulic circuits 8, 9. 3. A hydraulic circuit 8 for connecting the hydraulic pump 7 with the hydraulic motor 2a of the front wheel roller 1a and the hydraulic motor 2b of the rear wheel roller 1b, and a hydraulic circuit 8 connecting the hydraulic pump 7 with the hydraulic motor of the front wheel roller 1a and the rear wheel roller 1b. A hydraulic circuit 9 for connecting to the hydraulic motor 2b is connected by a parallel circuit, and a hydraulic circuit 8 and a hydraulic circuit 8 are connected to the hydraulic circuit 8 and 9 on the throttle valve 15 side of a pair of fuse valves 13 each including a shutoff path 14 and a throttle valve 15. And the hydraulic motors 2a, 2a,
2. The automatic control apparatus for a load roller according to claim 1, wherein a pilot circuit is connected between the side 2b and the cutoff path 14.