JPH0658136U - Engine stall prevention equipment for construction machinery - Google Patents

Abstract

(57) [Summary] [Purpose] To prevent the engine from stalling when the machine is rotated at a low speed in order to perform the fall prevention control of the construction machine. [Configuration] When the fall prevention controller 26 sends a signal that there is a risk of falling, the engine E is decelerated to a predetermined rotation speed, and the electronic governor controller 27 is configured to increase the engine output torque.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a technique for preventing an engine stall when performing a fall prevention control of a construction machine.

[0002]

[Prior art]

 In the past, in order to prevent construction machinery from tipping over during work, when there was a risk of tipping over, the engine speed was reduced to let the operator recognize it and slow down the work speed to avoid danger. In the backhoe, a counterweight was installed near the engine to improve the front-rear weight balance.

[0003]

[Problems to be solved by the device]

 However, if the engine speed is lowered when there is a risk of tipping as in the past, the engine will be overloaded and the engine will be in the low speed range, which may cause engine stall. Sometimes it was impossible to return to the initial position by releasing the lock and it became impossible to escape, which could be dangerous. In addition, if the output torque is increased in all engine speeds so that the engine will not stall in the low engine speed range, black smoke will be more likely to be emitted and combustion efficiency will be deteriorated. Then, when trying to increase the engine output torque and to make the exhaust color clean, the engine itself becomes large.

[0004]

[Means for solving the problem]

 The problems to be solved by the present invention are as described above. Next, means for solving the problems will be described. In other words, in a construction machine equipped with a fall prevention control device that reduces the speed of the engine and slows down the engine speed, there is a risk of falling, and if it is detected that there is a risk of falling, the engine will be decelerated to a specified speed and engine output It is configured to increase the torque. The engine cooling water and radiator cooling water drain ports are provided on the counterweight for stabilizing the vehicle balance.

[0005]

[Action]

 Next, the operation will be described. If there is a risk of falling, a signal is sent from the fall prevention controller 26 and the electronic governor controller 27 adjusts the governor to rotate the engine E at a low speed, and when it enters the low speed range, the output torque of the engine is increased by a% and the engine stalls. If there is no risk of falling, the fall prevention controller 26 sends a signal for canceling the fall prevention control to the electronic governor controller 27, and the electronic governor controller 27 sets the engine speed to the value indicated by the accelerator lever. The governor is controlled and the output torque characteristic is returned to the normal value. Then, the cooling water is discharged from the drain port provided in the counter weight, and the hose connecting it is a pipe that avoids the muffler and the fan belt.

[0006]

【Example】

 Next, an embodiment of a backhoe using the present invention as a construction machine will be described. Fig. 1 is a side view of the entire backhoe, Fig. 2 is a diagram showing the relationship between engine speed and torque, Fig. 3 is a block diagram when torque control is performed using an electronic governor, and Fig. 4 is a control flow chart. 5 is a block diagram when torque control is performed using a solenoid, FIG. 6 is a diagram showing the arrangement of the cooling water drain, FIG. 7 is a diagram showing the arrangement of the conventional cooling water drain, and FIG. 8 is the fuel supply of the fuel tank. It is sectional drawing which shows a part.

To explain the overall structure of the backhoe in FIG. 1, the upper frame 3 is placed on the crawler type traveling device 1 via the swivel base 2, and the blade 4 is projected rearward from the track frame of the crawler type traveling device 1. A boom 5 is rotatably mounted on the front end of the upper frame 3 so that it can be rotated forward and backward and left and right, and a bucket 7 is attached to the end of the boom 5 via a swing arm 6. Then, by rotating them respectively, excavation work can be performed. Behind the base of the boom 5, a front column 9 having an operation lever, a display panel and the like is erected, a seat 10 is provided at the rear of the front column 9, and an engine compartment 11 is provided at the rear of the seat 10. ing.

An engine E, a hydraulic pump, a radiator 12, a fuel tank 13 and the like are housed in the engine compartment 10, and a counterweight 15 is arranged at the rear end for balancing the front-rear weight. As shown in FIG. 7, the drain port 16 for discharging the cooling water from the engine E and the radiator 12 is provided with a drain port 16 'consisting of a three-way cock on the upper frame 3 as shown in FIG. The branch pipes of the engine were connected to the drain ports of the engine E and the radiator 12 via the hoses 17 and 18, respectively, but the hose 17 that connects the radiator 12 and the drain port 16 'is connected to the muffler 14 and the fan belt of the engine. It was easy to interfere with and was unreliable. Therefore, according to the present invention, as shown in FIG. 6, the counterweight 15 is provided with a through hole 15a and a drain port 16 is provided on the upper part thereof, and the drain ports 16 are connected with hoses 17 and 18, and the through hole 15a is connected to the through hole 15a. A drain plug 19 is screwed onto the lower end of the 15a to cover it, so that the hose 17 extends rearward so that the radiator 12 and the drain port 16 are connected to each other, which may interfere with the muffler 14 and the fan belt of the engine. Will not be.

Further, as shown in FIG. 8, the fuel tank 13 is provided with a manual pressure feed pump 20. In the conventional case, even if fuel is replenished with about 1/3 when the fuel runs out, the fuel strainer is operated. If air was trapped in the pipe containing the liquid, the liquid level was low, and it could not be possible to suck up the fuel from the fuel tank even if the fuel supply pump was manually operated. In view of this, in this configuration, the manual pressure pump 20 can easily remove the air pockets to supply the fuel. That is, the pressure feed pump 20 is provided upright on the discharge port 13a of the fuel tank 13, and the discharge port 13a is provided with a valve 21 (which does not flow back to the fuel tank side) capable of communicating only in the discharge direction. A suction port 20d is opened at the bottom of the fuel tank 13 below the cylinder 20a of the pressure pump 20, and a valve 22 is provided at the suction port 20d so as to be able to communicate only in the suction direction. Therefore, when the piston rod 20c is lifted up, the fuel in the fuel tank 13 is sucked into the cylinder 20a from the valve 22, and when the piston rod 20c is lowered, the fuel in the cylinder 20a is transferred to the cosmic vessel via the valve 21. The air can be supplied to the engine by removing the air pockets on the fuel pipe. The piston 20b is normally held at the position shown by the dotted line.

The engine E is controlled so as to reduce the number of revolutions of the engine E 1 when there is a risk of falling during the work. That is, as shown in FIG. 3, the machine is provided with a fall prevention controller 26, and the tilt sensor 25 is connected to the fall prevention controller 26, and the tilt sensor 25 constantly detects the tilt of the machine. However, as shown in FIG. 1, when the blade 4 is lowered or the bucket 7 is tilted when excavating, and there is a risk of falling if the angle exceeds the set angle, the fall prevention controller 26 causes the electronic governor controller 27 to fall. The engine E is controlled by sending a signal to the engine.

As shown in FIG. 4, the control of the engine E is performed by controlling the governor of the engine E from the electronic governor controller 27 so that the rotation speed of the engine E becomes low when there is a risk of falling. When the torque is increased by a% (for example, 10%) in the low speed range and there is no risk of falling, the engine E speed is set as the accelerator lever indicates, and the output torque of the engine E is 100% as a characteristic value. It is set to be%.

That is, this characteristic is as shown in FIG. 2, and normally, as shown by the solid line b, when traveling, it is possible between the rotational speeds r1 to r4. Since a torque higher than the torque is required, work can be performed at a rotation speed between r2 and r3. However, if there is a risk of overturning during work, the engine E speed will be reduced to improve safety, but if the rotation speed is reduced to r2 or less, the engine output torque will be lower than the required hydraulic pump torque. It ends up being an engine stall. If this happens, the engine will stop and you will not be able to work or run, so you will not be able to avoid falling.

Therefore, only when the engine E has a risk of falling and the rotation speed of the engine E is reduced, the electronic governor controller 27 adjusts the governor in response to a signal of danger of falling as indicated by a chain line c 1. When E is rotated at a low speed and the low speed rotation range is entered, the governor is controlled so that the output torque of the engine is increased by a%. When there is no risk of falling, or when there is no risk of falling, the fall prevention controller 26 sends a signal for canceling the fall prevention control to the electronic governor controller 27, and the electronic governor controller 27 indicates the engine speed by the accelerator lever. The governor is controlled so that it becomes the value, and the output torque characteristic is also returned to the normal (100%) value.

The governor can be controlled by using a solenoid instead of an electronic type. As shown in FIG. 5, the fall prevention controller 26 'includes a fixed engine low speed rotation solenoid 28 and a limit position changing solenoid for the governor. When 29 is connected and there is a risk of overturning, the overturn prevention controller 26 turns on the engine low-speed rotation fixed solenoid 28 to reduce the engine speed to a low speed, and at the same time turns on the governor limit position changing solenoid 29 and turns the torque. Increase characteristics by a% above normal to prevent engine stalling. When there is no risk of falling, the fall prevention controller 26 turns off the engine low speed rotation fixed solenoid 28, controls the governor so that the engine speed becomes the value indicated by the accelerator lever, and simultaneously changes the limit position of the governor. The solenoid 29 is turned off and the torque characteristic is returned to normal.

[0015]

[Effect of device]

 Since the present invention is configured as described above, it has the following effects. That is, since it is configured as in claim 1, even if there is a risk of overturning and the engine is turned over at a low speed due to overturning prevention control, black smoke is generated from the engine and an incomplete combustion state occurs. There was no stalling, and it became possible to promptly take actions to avoid danger and ensure safety.

Since the drain hose of the cooling water does not interfere with the muffler, the fan belt and the like, the construction such as assembling can be easily performed.

[Brief description of drawings]

FIG. 1 is an overall side view of a backhoe.

FIG. 2 is a diagram showing a relationship between engine speed and torque.

FIG. 3 is a block diagram when torque control is performed using an electronic governor.

FIG. 4 is a control flowchart.

FIG. 5 is a block diagram when torque control is performed using a solenoid.

FIG. 6 is a diagram showing an arrangement of cooling water drains.

FIG. 7 is a diagram showing an arrangement of a conventional cooling water drain.

FIG. 8 is a cross-sectional view showing a fuel supply section of a fuel tank.

[Explanation of symbols]

 E engine 11 engine compartment 12 radiator 15 counterweight 16 drain port 26 fall prevention controller 27 electronic governor controller

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Reference number within the agency FI Technical display location F02D 41/22 380 C 8011-3G (72) Inventor Hideo Shimazoe 428 Enami, Okayama City Seirei Industrial Co., Ltd. Meeting

Claims (2)

[Scope of utility model registration request] 1. In a construction machine equipped with a fall prevention control mechanism that slows down the engine speed when it reaches a region where there is a risk of fall and slows down the working machine speed, when it detects that there is a risk of fall, the engine is rotated at a predetermined rotational speed. A stall prevention device for a construction machine, characterized in that the engine output torque is increased to reduce the engine speed. 2. A construction machine characterized in that a counterweight for stabilizing vehicle balance is provided with a drain port for cooling water for an engine and cooling water for a radiator.