CN116745490A - Construction machine and method for controlling construction machine - Google Patents

Abstract

The lifting frame is rotatably supported on the vehicle body around a lifting shaft. The blade is rotatably supported by the lift frame about a pitch axis. The lifting actuator is connected with the lifting frame and the vehicle body, so that the lifting frame can lift up and down around the lifting shaft. The pitching actuator is connected with the scraping plate and the lifting frame, so that the scraping plate can perform pitching motion around a pitching axis. The sensor detects the height of the blade from a reference height determined based on the vehicle body. The controller controls the pitch actuator according to the height of the blade to change the pitch angle of the blade.

Description

Construction machine and method for controlling construction machine

Technical Field

The present invention relates to a construction machine and a method for controlling a construction machine.

Background

Among the construction machines, there is a construction machine capable of adjusting a pitch angle of a blade according to an operation by an operator. For example, in the construction machine of patent document 1, an operation lever for adjusting a pitch angle of a blade is provided. The operation lever is provided with a switch. If the operation lever is tilted to the right when the switch is on, the hydraulic cylinder is controlled to tilt the squeegee forward (forward tilting). If the operation lever is tilted to the left when the switch is on, the hydraulic cylinder is controlled to tilt the blade backward (backward).

Prior art literature

Patent literature

Patent document 1 (Japanese patent application) JP-A-7-252859

Disclosure of Invention

Problems to be solved by the invention

The pitch angle of the blade affects workability such as excavation and earth leveling. However, the pitch angle of the blade is different depending on the work. For example, when the pitch angle is large, that is, when the blade is tilted forward, the earth leveling property is good, but the excavation resistance is large and the excavation property is low. When the pitch angle is small, that is, when the blade is tilted backward, the excavation resistance is small and the excavation performance is good, but the blade is much spilled backward and the earth leveling performance is low.

Therefore, even a skilled operator cannot easily and manually select a proper pitch angle accurately. The purpose of the present disclosure is to enable easy and appropriate adjustment of the pitch angle of a blade in a construction machine.

Technical scheme for solving problems

The construction machine according to the first aspect of the present disclosure includes a vehicle body, a hoisting frame, a screed, a hoisting actuator, a pitch actuator, a sensor, and a controller. The lifting frame is rotatably supported on the vehicle body about a lifting shaft. The blade is rotatably supported by the lifting frame about a pitch axis. The lifting actuator is connected with the lifting frame and the vehicle body, so that the lifting frame can lift up and down around the lifting shaft. The pitching actuator is connected with the scraping plate and the lifting frame, so that the scraping plate can perform pitching motion around a pitching axis. The sensor detects the height of the blade from a reference height determined based on the vehicle body. The controller controls the pitch actuator to change the pitch angle of the blade according to the height of the blade.

The method of the second aspect of the present disclosure is a method for controlling a work machine. The construction machine is provided with a vehicle body, a lifting frame, a scraper, a lifting actuator, and a pitching actuator. The lifting frame is rotatably supported on the vehicle body around a lifting shaft. The blade is rotatably supported by the lift frame about a pitch axis. The lifting actuator is connected with the lifting frame and the vehicle body, so that the lifting frame can lift up and down around the lifting shaft. The pitching actuator is connected with the scraping plate and the lifting frame, so that the scraping plate can perform pitching motion around a pitching axis. The method comprises the following steps: detecting the height of the scraper from a reference height determined based on the vehicle body; the pitch actuator is controlled to change the pitch angle of the blade in accordance with the height of the blade.

Effects of the invention

According to the present disclosure, a pitch actuator is automatically controlled to change a pitch angle of a blade according to a height of the blade. Thus, the pitch angle of the blade can be easily and appropriately adjusted in the construction machine.

Drawings

Fig. 1 is a side view showing a construction machine according to an embodiment.

Fig. 2 is a block diagram showing the configuration of a drive train and a control system of the construction machine.

Fig. 3 is a view showing the height of the squeegee from the reference height.

Fig. 4 is a view showing a pitch angle of the blade.

Fig. 5 is a diagram showing an example of pitch angle data.

Fig. 6 is a diagram showing a pitching operation of the blade when the height of the blade is equal to or greater than the reference height.

Fig. 7 is a diagram showing a pitching operation of the blade when the height of the blade is equal to or less than the reference height.

Detailed Description

The construction machine according to the embodiment will be described below with reference to the drawings. Fig. 1 is a side view of a construction machine 1 according to an embodiment. The working machine 1 of the present embodiment is a bulldozer. The work machine 1 includes a vehicle body 11 and a work implement 12.

The vehicle body 11 includes a cab 13, an engine room 14, and a traveling device 15. A driver seat, not shown, is disposed in the driver cab 13. The engine room 14 is disposed in front of the cab 13. The traveling device 15 is provided at a lower portion of the vehicle body 11. The traveling device 15 includes a pair of left and right crawler belts 16. In fig. 1, only the left crawler belt 16 is illustrated. By the rotation of the crawler belt 16, the working machine 1 runs.

The work implement 12 is mounted to the vehicle body 11. The working device 12 has a lifting frame 17, a screed 18, a lifting actuator 19, and a pitch actuator 20. The lift frame 17 is rotatably supported by the vehicle body 11 about a lift axis X1. The lift axis X1 extends in the lateral direction of the vehicle body 11. The lifting frame 17 performs a lifting operation up and down by rotating about the lifting axis X1.

The blade 18 is disposed in front of the vehicle body 11. The blade 18 is rotatably supported by the lift frame 17 about the pitch axis X2. The pitch axis X2 extends in the lateral direction of the vehicle body 11. The blade 18 performs a pitching operation back and forth by rotating about the pitch axis X2. The scraper 18 moves up and down with the up and down movement of the lifting frame 17.

The lift actuator 19 is coupled to the vehicle body 11 and the lift frame 17. The lift actuator 19 is a hydraulic cylinder. The lifting actuator 19 expands and contracts, and the lifting frame 17 performs a lifting operation up and down. By the retraction of the lift actuator 19, the squeegee 18 is raised. The blade 18 is lowered by extension of the lift actuator 19.

The pitch actuator 20 is coupled to the lifting frame 17 and the blade 18. The pitch actuator 20 is a hydraulic cylinder. The pitch actuator 20 expands and contracts, and the blade 18 performs a pitch operation in the front-rear direction. The blade 18 is tilted about the tilt axis X2 by a part of the blade 18, for example, the upper end thereof being moved back and forth. The blade 18 is tilted forward by extension of the pitch actuator 20. By retraction of the pitch actuator 20, the blade 18 is reclined.

Fig. 2 is a block diagram showing the configuration of the drive train 2 and the control system 3 of the construction machine 1. As shown in fig. 2, the drive train 2 includes an engine 22, a hydraulic pump 23, and a power transmission device 24. The hydraulic pump 23 is driven by the engine 22 and discharges hydraulic oil. The hydraulic oil discharged from the hydraulic pump 23 is supplied to the lift actuator 19 and the pitch actuator 20. In fig. 2, one hydraulic pump is illustrated, but a plurality of hydraulic pumps may be provided.

The power transmission device 24 transmits the driving force of the engine 22 to the running device 15. The power transmission device 24 may also be, for example, an HST (Hydro Static Transmission ). Alternatively, the power transmission device 24 may be, for example, a torque converter or a transmission having a plurality of speed change gears.

The control system 3 includes a controller 26 and a control valve 27. The controller 26 is programmed to control the work machine 1 based on the acquired data. The controller 26 includes a memory device 28 and a processor 29. The processor 29 includes, for example, a CPU. The storage 28 includes, for example, a memory and a secondary storage. The storage device 28 may be, for example, a RAM, a ROM, or the like. The storage device 28 may be a semiconductor memory, a hard disk, or the like. The storage device 28 is one example of a non-transitory (non-transitory) computer-readable recording medium. The storage device 28 records computer instructions executable by the processor 29 and for controlling the work machine 1.

The control valve 27 is a proportional control valve, and is controlled by a command signal from the controller 26. The control valve 27 is disposed between a hydraulic actuator such as the lift actuator 19 and the pitch actuator 20 and the hydraulic pump 23. The control valve 27 controls the flow rate of the hydraulic oil supplied from the hydraulic pump 23 to the lift actuator 19. The control valve 27 controls the flow rate of the hydraulic oil supplied from the hydraulic pump 23 to the pitch actuator 20. The control valve 27 may be a pressure proportional control valve. Alternatively, the control valve 27 may be a solenoid proportional control valve.

The control system 3 includes an operation device 31 and an input device 32. The operating means 31 comprise, for example, a lever. Alternatively, the operating device 31 may also include a pedal, or a switch. The operator can manually operate the traveling of the working machine 1 and the operation of the work implement 12 using the operation device 31. The operation device 31 outputs an operation signal indicating the operation of the operation device 31. The controller 26 receives an operation signal from the operation device 31.

The operating device 31 is capable of operating the lifting motion of the blade 18. In detail, the operation device 31 can perform operations of lifting and lowering the blade 18. When the operator performs a lifting operation on the operation device 31, the controller 26 controls the lifting actuator 19 to raise the squeegee 18. When the operator performs a lowering operation on the operation device 31, the controller 26 controls the lift actuator 19 to lower the squeegee 18.

The operating device 31 is capable of operating the pitching motion of the blade 18. Specifically, the operation device 31 can perform the forward tilting operation and the backward tilting operation of the blade 18. When the operator performs a forward tilting operation on the operation device 31, the controller 26 controls the pitch actuator 20 to tilt the blade 18 forward. When the operator performs a backward tilting operation on the operation device 31, the controller 26 controls the pitch actuator 20 to backward tilt the blade 18.

The operation device 31 may be a hydraulic pilot type device. For example, the operating device 31 may output a pilot hydraulic pressure corresponding to an operation of the operating device 31. The lift actuator 19 or the pitch actuator 20 may be controlled by controlling the control valve 27 with pilot hydraulic pressure from the operation device 31. The controller 26 may also receive a signal indicative of the pilot hydraulic pressure as the operation signal.

The input device 32 includes, for example, a touch panel. However, the input device 32 may include other devices such as a switch. The operator can set the control mode of the pitch angle of the blade 18 by the controller 26 using the operation device 31. The control mode of the pitch angle of the blade 18 will be described in detail later.

The control system 3 includes a sensor 33 that detects the height of the blade 18. The sensors 33 include a body sensor 34, a rack sensor 35, and a squeegee sensor 36. The vehicle body sensor 34 is mounted to the vehicle body 11. The body sensor 34 detects the posture of the vehicle body 11. The frame sensor 35 is mounted to the lifting frame 17. The rack sensor 35 detects the posture of the lifting rack 17. Blade sensor 36 is mounted to blade 18. The blade sensor 36 detects the posture of the blade 18.

The body sensor 34, the frame sensor 35, and the blade sensor 36 are IMUs (inertial measurement units, inertial Measurement Unit), respectively. However, the rack sensor 35 and the blade sensor 36 are not limited to the IMU, and may be other sensors such as an angle sensor and a stroke sensor of a cylinder.

The vehicle body sensor 34 detects an angle (vehicle body pitch angle) of the vehicle body 11 with respect to the horizontal front-rear direction. The frame sensor 35 detects the rotation angle of the lifting frame 17. The blade sensor 36 detects the pitch angle of the blade 18. The body sensor 34, the rack sensor 35, and the blade sensor 36 each output a detection signal indicating the detected angle.

The controller 26 receives detection signals from the body sensor 34, the rack sensor 35, and the blade sensor 36. The controller 26 calculates the height of the blade 18 from the reference height H0 determined based on the vehicle body 11 based on the detection signal. As shown in fig. 3, the reference height H0 is the height of the ground contact surface G1 of the crawler 16. The height of the blade 18 is the height of the blade tip P0 of the blade 18 from the ground plane G1.

The controller 26 stores mechanical dimension data indicating the dimensional and positional relationship of the vehicle body 11, the lifting frame 17, and the screed 18. The controller 26 calculates the height of the screed 18 from the reference height H0 based on the angle and mechanical dimension data detected by the body sensor 34, the frame sensor 35, and the screed sensor 36.

As shown in fig. 3, in a state where the blade tip P0 of the blade 18 is placed on the ground contact surface G1 of the crawler 16, the height of the blade 18 is 0. When the blade tip P0 of the blade 18 is located above the ground contact surface G1 of the crawler 16, the height of the blade 18 becomes a positive value. When the blade tip P0 of the blade 18 is located below the ground contact surface G1 of the crawler 16, the height of the blade 18 becomes negative. In fig. 3, P1 represents the highest position of the blade edge P0 of the blade 18. P2 represents the lowest position of the blade tip P0 of the blade 18. The working machine 1 can lift the blade 18 between the highest position P1 and the lowest position P2.

Next, a control mode of the pitch angle of the blade 18 will be described. The control modes of the pitch angle of the blade 18 include an automatic mode and a manual mode. The controller 26 switches between the automatic mode and the manual mode according to the operation of the input device 32. The operator can select the automatic mode and the manual mode by operating the input device 32.

In the automatic mode, the controller 26 controls the pitch actuator 20 to change the pitch angle of the blade 18 according to the height of the blade 18 from the reference height H0. Fig. 4A to 4C are diagrams showing the pitch angle of the blade 18. As shown in fig. 4A to 4C, the pitch angles θ1 to θ3 of the blade 18 are angles formed between the blade tip P0 of the blade 18 and the ground contact surface G1 of the crawler 16. Fig. 4B shows the pitch angle θ2 of the blade 18 in the standard state. Fig. 4A shows the pitch angle θ1 of the blade 18 tilted forward in comparison with the standard state. Fig. 4C shows the pitch angle θ3 of the blade 18 tilted backward compared to the standard state. The pitch angle becomes greater the more forward the blade 18 is tilted. The pitch angle becomes smaller as the blade 18 leans backward. I.e., θ1 > θ2 > θ3.

The controller 26 stores pitch angle data. The pitch angle data specifies the relationship between the height of the blade 18 and the target pitch angle of the blade 18. The pitch angle data is stored in the controller 26, for example, in the form of a graph. However, the pitch angle data is not limited to the graph, and may be stored in the controller 26 in other forms such as a mathematical expression.

The controller 26 refers to the pitch angle data and determines a target pitch angle from the height of the blade 18. The controller 26 controls the pitch actuator 20 so that the pitch angle of the blade 18 becomes a target pitch angle. Fig. 5 is a diagram showing an example of pitch angle data. In fig. 5, a solid line shows an example of pitch angle data in the present embodiment.

In fig. 5, the two-dot chain line indicates a change in the pitch angle when the control mode of the pitch angle is not performed. That is, in fig. 5, the two-dot chain line indicates a change in the pitch angle (hereinafter referred to as a pitch angle in the non-control) when the pitch operation of the blade 18 is fixed. When the pitch motion is fixed, as shown by the two-dot chain line in fig. 5, the pitch angle changes in proportion to the change in the height of the blade 18 between the maximum value Hmax and the minimum value Hmin. The change in pitch angle at the time of non-control indicates a change in pitch angle caused by rotation of the lift frame 17 about the lift axis X1. In the non-control, the pitch angle decreases at a constant rate relative to the increase in height of the blade 18.

On the other hand, in the pitch angle data in the automatic mode in the present embodiment, a target pitch angle larger than that in the non-control is defined for the height of the blade 18 larger than 0. Accordingly, as shown in fig. 6, the controller 26 controls the pitch actuator 20 so that the blade 18 tilts forward when compared to when not in control, when the blade 18 is located above the reference height H0. In fig. 6, the two-dot chain line indicates the posture of the squeegee 18 when not in control.

As shown in fig. 5, the absolute value of the inclination of the pitch angle data in the first range (0 to H1) is larger for the height of the blade 18 than for the non-control. The first range (0-H1) is a range in which the height of the blade 18 is 0 to H1. H1 is a value between 0 and Hmax. The absolute value of the inclination of the pitch angle data of the blade 18 in the second range (H1-Hmax) is the same as that in the non-control. The second range is a range in which the height of the squeegee 18 is H1 to Hmax.

When the height of the blade 18 is within the first range (0 to H1), the controller 26 changes the pitch angle of the blade 18 in a direction to tilt the blade 18 forward according to an increase in the height of the blade 18. The controller 26 fixes the pitching action of the blade 18 by the pitching actuator 20 when the height of the blade 18 is within the second range (H1-Hmax).

The pitch angle data in the automatic mode in the present embodiment specifies a target pitch angle smaller than that in the non-control for the height of the blade 18 smaller than 0. Accordingly, as shown in fig. 7, the controller 26 controls the pitch actuator 20 so that the blade 18 tilts backward when compared to the non-control when the blade 18 is located below the reference height H0. In fig. 7, the two-dot chain line indicates the posture of the squeegee 18 when not in control.

Further, as shown in fig. 5, when the height of the blade 18 is within the third range (0 to H2), the pitch angle decreases according to the decrease in the height of the blade 18. The third range (0-H2) is a range in which the height of the blade 18 is 0 to H2. H2 is a value between 0 and Hmin. The absolute value of the inclination of the pitch angle data of the blade 18 in the fourth range (H2-Hmin) is the same as that in the non-control. The fourth range (H2-Hmin) is a range in which the height of the blade 18 is H2 to Hmin.

When the height of the blade 18 is within the third range (0 to H2), the controller 26 changes the pitch angle of the blade 18 in a direction to recline the blade 18 according to the decrease in the height of the blade 18. The controller 26 fixes the pitching action of the blade 18 by the pitching actuator 20 when the height of the blade 18 is within the fourth range (H2-Hmin).

In the manual mode, the pitch actuator 20 is controlled to change the pitch angle of the blade 18 in accordance with the operation of the operation device 31. In addition, when the operation device 31 is not operated, the pitch actuator 20 is controlled to maintain the pitch angle of the blade 18. For example, when the operation device 31 is not operated, the controller 26 controls the pitch actuator 20 to maintain the pitch angle of the blade 18 even if a part of the working oil leaks in the control valve 27.

In the construction machine 1 of the present embodiment described above, in the automatic mode, the pitch actuator 20 is automatically controlled according to the height of the blade 18 to change the pitch angle of the blade 18. Thus, the pitch angle of the blade 18 can be easily and appropriately adjusted in the working machine 1.

For example, when the blade 18 is located above the reference height H0, the pitch actuator 20 is controlled so that the blade 18 tilts forward as compared to when not in control. When the blade 18 is located above the reference height H0, earth leveling or bulldozing is often performed. Therefore, when the blade 18 is positioned above the reference height H0, workability in a soil leveling or soil shifting operation is improved by tilting the blade 18 forward.

When the blade 18 is located below the reference height H0, the pitch actuator 20 is controlled so that the blade 18 tilts backward as compared with the non-control. When the blade 18 is positioned below the reference height H0, the excavation work is often performed. Therefore, when the blade 18 is positioned below the reference height H0, workability in the excavation work is improved by the blade 18 tilting backward.

As described above, in the construction machine 1 of the present embodiment described above, the pitch angle of the blade 18 can be easily and appropriately adjusted in accordance with the work content by the automatic mode.

While the embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications may be made without departing from the spirit of the invention.

The working machine 1 is not limited to a bulldozer, and may be another vehicle such as a wheel loader or a motor grader. The controller 26 may have a plurality of controllers independent of each other. The processing by the controller 26 is not limited to the above embodiment, and may be modified. A part of the processing in the automatic mode or the manual mode described above may be omitted. Alternatively, part of the above-described processing may be modified.

The lift actuator 19 and the pitch actuator 20 are not limited to hydraulic cylinders. The lift actuator 19 and the pitch actuator 20 may be other actuators such as an electric motor. The pitch angle data is not limited to the above embodiment, and may be changed. For example, when the pitch angle data is within the second range, the pitch angle data may have a different inclination from that when uncontrolled. When the pitch angle data is within the fourth range, the pitch angle data may have a different inclination from that in the non-control.

Industrial applicability

According to the present disclosure, in a construction machine, the pitch angle of a blade can be easily and appropriately adjusted.

Description of the reference numerals

11 vehicle body

16 caterpillar band

17 lifting frame

18 scraping plate

19 lift actuator

20 pitch actuator

26 controller

31 operating device

33 sensor

Claims (16)

1. A construction machine is characterized by comprising:

a vehicle body;

a lifting frame rotatably supported by the vehicle body about a lifting shaft;

a blade rotatably supported by the lifting frame about a pitch axis;

a lifting actuator connected to the lifting frame and the vehicle body, the lifting actuator causing the lifting frame to lift up and down around the lifting shaft;

a pitch actuator connected to the blade and the lifting frame, and configured to pitch the blade about the pitch axis;

a sensor that detects a height of the blade from a reference height determined based on the vehicle body;

and a controller that controls the pitch actuator according to the height of the blade to change the pitch angle of the blade.

2. The construction machine according to claim 1, wherein,

the controller controls the pitch actuator to tilt forward when the blade is above the reference height as compared to when the pitch action of the blade is fixed.

3. The construction machine according to claim 2, wherein,

the controller controls the pitch actuator to change a pitch angle of the blade in a direction to tilt the blade forward according to an increase in the height of the blade when the blade is located above the reference height.

4. The construction machine according to any one of claim 1 to 3, wherein,

the controller controls the pitch actuator to recline when the blade is positioned below the reference height, as compared to when the pitch of the blade is fixed.

5. The construction machine according to claim 4, wherein,

the controller controls the pitch actuator to change a pitch angle of the blade in a direction to recline the blade in accordance with a decrease in the height of the blade when the blade is located below the reference height.

6. The construction machine according to any one of claims 1 to 5, wherein,

the vehicle body includes a track that is coupled to the vehicle body,

the reference height is a height of a ground-contacting surface of the track.

7. The construction machine according to any one of claims 1 to 6, wherein,

the controller stores pitch angle data defining a relationship between a height of the screed and a target pitch angle of the screed,

the target pitch angle is determined with reference to the pitch angle data and according to the height of the blade,

the pitch actuator is controlled so that the pitch angle of the blade becomes the target pitch angle.

8. The construction machine according to any one of claims 1 to 7, wherein,

further comprising an operating device for manually operating the pitch angle of the blade,

the controller acquires an operation signal indicating an operation of the operation device,

controlling the pitch actuator to change the pitch angle of the blade in accordance with the operation of the operation device,

the pitch actuator is controlled to maintain a pitch angle of the blade when the operating device is not operated.

9. A method for controlling a construction machine, the construction machine comprising: a vehicle body; a lifting frame rotatably supported by the vehicle body about a lifting shaft; a blade rotatably supported by the lifting frame about a pitch axis; a lifting actuator connected to the lifting frame and the vehicle body, the lifting actuator causing the lifting frame to lift up and down around the lifting shaft; a pitch actuator connected to the blade and the lifting frame, for pitching the blade about the pitch axis, the pitch actuator comprising:

detecting a height of the blade from a reference height determined based on the vehicle body;

the pitch actuator is controlled to change the pitch angle of the blade according to the height of the blade.

10. The method according to claim 9, further comprising:

the pitch actuator is controlled so that the blade tilts forward when the pitch action of the blade is fixed as compared to when the blade is above the reference height.

11. The method according to claim 10, further comprising:

when the blade is positioned above the reference height, the pitch actuator is controlled to change the pitch angle of the blade in a direction to tilt the blade forward according to an increase in the height of the blade.

12. The method according to any one of claims 9 to 11, further comprising:

the pitch actuator is controlled so that the blade is tilted backward when compared with the pitch action of the blade when the blade is positioned below the reference height.

13. The method according to claim 12, further comprising:

when the blade is positioned below the reference height, the pitch actuator is controlled to change the pitch angle of the blade in a direction to recline the blade in accordance with a decrease in the height of the blade.

14. The method according to any one of claims 9 to 13, wherein,

the vehicle body includes a track that is coupled to the vehicle body,

the reference height is a height of a ground-contacting surface of the track.

15. The method according to any one of claims 9 to 14, further comprising:

determining a target pitch angle according to the height of the blade by referring to pitch angle data defining a relation between the height of the blade and the target pitch angle of the blade;

the pitch actuator is controlled so that the pitch angle of the blade becomes the target pitch angle.

16. The method according to any one of claims 9 to 15, further comprising:

acquiring an operation signal indicating an operation of an operation device for manually operating a pitch angle of the blade;

controlling the pitch actuator to change a pitch angle of the blade in accordance with an operation of the operation device;

the pitch actuator is controlled to maintain a pitch angle of the blade when the operating device is not operated.