JP6113103B2 - Front loader - Google Patents

Description

  The present invention provides a boom actuator that swings the boom up and down around a first support shaft that is laterally oriented with respect to the traveling vehicle body, and a second support shaft that is laterally oriented with respect to the boom. The present invention relates to a front loader including a bucket actuator that swings in the vertical direction.

  In the front loader as described above, the angular velocity at the time of artificial control of the boom is measured based on the signal from the boom sensor, and based on the measurement result, the target angular velocity necessary for the bucket to maintain the vehicle body posture is obtained, Some control devices include speed control means for controlling the operation speed of the bucket actuator so that the target angular velocity is measured by a bucket sensor (see, for example, Patent Document 1).

Japanese Patent Laid-Open No. 10-245866

  In the above configuration, since the operation speed of the bucket actuator is controlled, the posture correction of the bucket with respect to the vertical swing of the boom is responsive in order to make the bucket swing angle constant regardless of the vertical swing of the boom. Can be done well.

  However, since the operation speed of the bucket actuator is controlled based on the boom angular velocity detected by the boom sensor, the control delay caused by the bucket posture correction with respect to the vertical swing of the boom has not been solved. There is room for improvement in maintaining the bucket swing angle at a constant level with higher accuracy.

  An object of the present invention is to enable the bucket swing angle to be kept constant with higher accuracy.

The problem solving means of the present invention is:
An actuator for a boom that swings up and down in a vertical direction with a first support shaft that is horizontally oriented with respect to the traveling vehicle body as a fulcrum;
A bucket actuator that swings the bucket up and down around a second support shaft that is laterally oriented with respect to the boom; and
A boom angle detector for detecting a vertical swing angle of the boom;
A bucket angle detector for detecting a vertical swing angle of the bucket with respect to the boom;
A calculation unit for calculating a ground swing angle of the bucket based on an output of the boom angle detector and an output of the bucket angle detector;
A manual control unit for controlling the operation of the boom actuator and the bucket actuator based on an operation command output by the command operation tool;
A ground angle maintenance control unit that controls the operation of the bucket actuator so that the bucket ground swing angle is constant regardless of the boom swinging up and down based on the output of the arithmetic unit;
With
The ground angle maintenance control unit
Determining whether or not the boom swinging angle when the boom is stopped is within a set angle from the boom lifting restriction angle;
When the command operating tool outputs a boom lowering operation command, the manual control unit precedes the lowering control operation for the boom actuator based on the operation command regardless of the determination result. Start the control operation for raising the bucket actuator,
When the command operation tool outputs an operation command for raising the boom,
When the determination result is outside the set angle, the control for lowering the bucket actuator is started prior to the manual control unit starting the control operation for raising the boom actuator based on the operation command. Start working,
When the determination result is within a set angle, the control operation for the bucket actuator is not performed.

  According to this means, when the boom is swung downward, the ground angle maintaining control unit controls the lowering of the boom actuator based on the operation command for lowering the boom from the command operating tool. Prior to starting the operation, based on the feedforward control for starting the control operation for raising the bucket actuator and the output of the calculation unit, the bucket swing angle to the ground regardless of the vertical swing of the boom Feedback control is performed to control the operation of the bucket actuator so as to be constant.

  In addition, when the boom is moved up and down when the boom vertical swing angle when the boom is stopped is outside the set angle from the boom lift restriction angle, the ground angle maintenance control unit Based on the ascending operation command, the manual control unit initiates the descending control operation for the bucket actuator before the manual control unit initiates the ascending control operation for the boom actuator, and calculation Based on the output of the unit, feedback control is performed to control the operation of the bucket actuator so that the bucket swing angle is constant regardless of the boom swinging up and down.

  When the boom is moved up and down when the boom vertical swing angle is within the set angle from the boom lift restriction angle when the boom is stopped, the ground angle maintenance control unit The control operation is not performed.

  That is, when the boom is swung downward, and when the boom is swung up and down when the vertical swing angle of the left and right booms is outside the set angle from the boom lift restriction angle, the feed forward By using the control and the feedback control in combination, it is possible to keep the bucket swing angle constant with high accuracy without causing a control delay of the bucket actuator.

  In addition, when the boom is swung up and down when the boom up and down swing angle is within the set angle from the boom lift restriction angle when the boom is stopped, feed boom control is not performed. In spite of being in a state in which almost no upward swinging is caused by being within a set angle from the point of time, the bucket swings in advance, and the ground swinging angle of the bucket cannot be maintained constant. Occurrence can be avoided.

  Therefore, regardless of the boom swinging up and down, the bucket swinging angle with respect to the ground can be maintained more accurately and constant.

It is a left view of the tractor equipped with the front loader. It is a left view which shows the operating state of a front loader. It is a block diagram which shows the control structure regarding a front loader. It is a figure which shows the operating speed at the time of a bucket automatic stop.

  Hereinafter, as an example of an embodiment for carrying out the present invention, an embodiment in which a front loader according to the present invention is mounted on a tractor as an example of a traveling vehicle body will be described with reference to the drawings.

  As shown in FIG. 1, the tractor A exemplified as the traveling vehicle body A in this embodiment includes a driving unit 2 and left and right front wheels 3 on the front side of the vehicle body frame 1. In addition, a cabin 5 that forms a boarding operation unit 4 and left and right rear wheels 6 are provided on the rear side of the body frame 1. Left and right support brackets 7 that allow the front loader B to be mounted are provided at the front and rear intermediate portions of the vehicle body frame 1. The boarding driver 4 includes a steering wheel 8 and a driver seat 9.

  As shown in FIGS. 1 to 3, the front loader B swings up and down via left and right fixed brackets 10 detachably attached to the corresponding support brackets 7, and the corresponding fixed brackets 10 via the first support shaft 11 facing left and right. The left and right swing brackets 14, the left and right swing brackets 14, the left and right swing brackets 14 connected to the free ends of the corresponding booms 12 via the second support shaft 13 facing left and right. Detachably connected bucket 15, hydraulic double-acting left and right boom cylinder 16 used as a boom actuator, hydraulic double-acting left and right bucket cylinder 17 used as a bucket actuator, either left or right A boom angle detector 18 that detects the vertical swing angle θa of one boom 12, and the vertical swing angle θ of the bucket 15 with respect to the left and right booms 12. A bucket angle detector 19 for detecting b is provided.

  The left and right boom cylinders 16 swing and drive the corresponding boom 12 with respect to the tractor A in the vertical direction with the first support shaft 11 as a fulcrum. The left and right bucket cylinders 17 swing the bucket 15 together with the left and right swing brackets 14 in the vertical direction with respect to each boom 12 with the second support shaft 13 as a fulcrum. The boom angle detector 18 and the bucket angle detector 19 employ a rotary potentiometer.

  As shown in FIG. 3, the tractor A includes a valve unit 20 that controls the flow of oil to the left and right boom cylinders 16 and the left and right bucket cylinders 17, and the left and right boom cylinders 16 and the left and right buckets via the valve unit 20. A front loader electronic control unit (hereinafter referred to as LD-ECU) 21 for controlling the operation of the cylinder 17 is provided.

  Although not shown, the hydraulic control unit 20 includes an electronic control valve for the boom that controls the flow of oil to the left and right boom cylinders 16 and an electronic control for the bucket that controls the flow of oil to the left and right bucket cylinders 17. Valve, etc.

  As shown in FIGS. 2 and 3, the LD-ECU 21 is configured by a microcomputer including a CPU, an EEPROM, and the like. And the manual control part 22 which enables manual operation of the right and left boom 12 and the bucket 15, the calculating part 23 which performs various arithmetic processing, the memory | storage part 24 which memorize | stores various data, and the ground swing of the bucket 15 A ground angle maintenance control unit 26 that performs ground angle maintenance control for maintaining the angle θc constant is provided.

  The manual control unit 22 is a front loader operation unit configured by a cross swing type neutral return type operation lever 30 provided in the boarding operation unit 4 and a lever operation detector 31 that detects an operation position of the operation lever 30. On the basis of the operation command output by the command operating tool 32, manual operation control for controlling the operation of the left and right boom cylinders 16 and the left and right bucket cylinders 17 is performed.

  In the manual operation control, when the operation command output from the command operating tool 32 is a boom raising operation command, the left and right booms 12 are swung up and down while the operation command is continuously output. The left and right boom cylinders 16 are extended. When the operation command output by the command operating tool 32 is a boom lowering operation command, the left and right boom cylinders 16 are arranged so that the left and right booms 12 swing downward while the operation command is continuously output. Operate the contraction. When the operation command output by the command operating tool 32 is an operation command for raising the bucket, while the operation command is continuously output, the left and right sides of the bucket 15 are moved up and down (scooping) The bucket cylinder 17 is contracted. When the operation command output from the command operating tool 32 is an operation command for lowering the bucket, the left and right sides of the bucket 15 swing downward (dump swing) while the operation command is continuously output. The bucket cylinder 17 is extended. When the command operating tool 32 stops outputting the operation command, the left and right boom cylinders 16 and the left and right boom cylinders 16 and so that the left and right booms 12 and the bucket 15 stop swinging while the output stop state is continued. The expansion / contraction operation of the left and right bucket cylinders 17 is stopped.

  The lever operation detector 31 includes a plurality of switches that detect a swing operation of the operation lever 30 to each operation position, or a rotary potentiometer that detects a swing operation of the operation lever 30 in the front-rear direction and a left-right direction. For example, a rotary potentiometer that detects a swinging operation to the head can be employed.

  The calculator 23 calculates the ground swing angle θc of the bucket 15 based on the output of the boom angle detector 18 and the output of the bucket angle detector 19. Then, the calculation result is output to the storage unit 24, the ground angle maintenance control unit 26, and the like.

  When the setting switch 33 for setting the control target angle provided in the boarding operation unit 4 is pressed, the storage unit 24 sets the ground swing angle θc of the bucket 15 output by the calculation unit 23 at that time to the ground. It is stored as a control target angle θco for angle maintenance control. That is, by operating the operation lever 30 to operate the left and right boom cylinders 16 and the left and right bucket cylinders 17 to operate the bucket 15 to a desired ground swing angle θc, and then pressing the setting switch 33. The ground swing angle θc of the bucket 15 at this time can be stored in the storage unit 24 as the control target angle θco for ground angle maintenance control. 2 illustrates a state in which the control target angle θco for the ground angle maintenance control is set to an angle at which the bottom surface of the bucket 15 becomes horizontal.

  Further, the bucket 15 is set to be lower than the rising limit angle θba by a set angle (for example, 2 degrees), and the bucket 15 is set to be higher by the set angle (for example, 2 degrees) than the lower limit angle θbc of the bucket 15. The descent restriction angle θbd of the bucket 15 is stored.

  As shown in FIGS. 2 to 4, when the ground angle maintenance control command switch 34 provided in the boarding operation unit 4 is pressed while the execution of the ground angle maintenance control is stopped, the ground angle maintenance control unit 26 Perform angle maintenance control. If the command switch 34 for ground angle maintenance control is pressed during execution of the ground angle maintenance control, the ground angle maintenance control is terminated.

  In the ground angle maintenance control, first, based on the output of the boom angle detector 18, the vertical swing angle θa of the left and right booms 12 when the boom is stopped is set from the ascent restriction angle θao of the left and right booms 12 (for example, 2 Degree).

Thereafter, when the command operating tool 32 outputs an operation command for lowering the boom, the manual control unit 22 starts a control operation for lowering the left and right boom cylinders 16 based on the operation command regardless of the determination result. Prior to this, the control operation for raising the left and right bucket cylinders 17 is started. Based on the control target angle θco for ground angle maintenance control stored in the storage unit 24 and the ground swing angle θc of the bucket 15 output by the calculation unit 23, regardless of the downward swing of the left and right booms 12, The operation of the left and right bucket cylinders 17 is controlled so that the ground swing angle θc of the bucket 15 coincides with the control target angle θco for ground angle maintenance control (contains within the dead zone width of the control target angle θco).
Conversely, when the command operation tool 32 outputs an operation command for raising the boom, the above-described determination result is reflected. If the determination result is out of the set angle, the manual control unit 22 moves the left and right based on the operation command. Prior to starting the control operation for raising the boom cylinder 16, the control operation for lowering the left and right bucket cylinders 17 is started.
If the determination result is within the set angle, the control operation for the left and right bucket cylinders 17 is not performed, and the bucket 15 is maintained in the current swinging posture.

  That is, when the command operating tool 32 outputs an operation command for lowering the boom, and when the boom is in a stopped state, the vertical swing angle θa of the left and right booms 12 is outside the set angle from the upward restriction angle θao of the left and right booms 12. When the command operating tool 32 outputs an operation command for raising the boom at a certain time, the bucket 15 is highly accurate without causing a control delay of the left and right bucket cylinders 17 by using the feed forward control and the feedback control together. Can be maintained at the control target angle θco (desired ground swing angle) for ground angle maintenance control.

  When the command operating tool 32 outputs an operation command for raising the boom when the vertical swing angle θa of the left and right booms 12 is within a set angle from the rise restriction angle θao of the left and right booms 12 when the boom is stopped. The ground swing angle θc of the bucket 15 is the ground angle due to the fact that the bucket 15 is swung down first in a state where the left and right booms 12 do not swing up and down by not performing the feedforward control. It is possible to avoid the occurrence of inconveniences that deviate significantly from the control target angle θco for maintenance control.

In the ground angle maintenance control, in addition to the above-described control operation, the ground angle maintenance control unit 26 sets the output of the bucket angle detector 18 and the rising restriction angle θbb and the falling restriction angle θbd of the bucket 15 stored in the storage unit 24. Based on this, when it is detected that the vertical swing angle θb of the bucket 15 has reached a deceleration angle θbx that is a set angle (for example, 10 degrees) before the ascending restriction angle θbb or the descending restriction angle θbd, Prior to the control operation of the manual control unit 22 based on the operation command, while the bucket 15 is located in the deceleration region H of the set angle (for example, 5 degrees) from the deceleration angle θbx, the oil is diverted to the left and right bucket cylinders 17. The duty ratio for the electronic control valve for the bucket is changed so that the ratio gradually decreases, and the operating speed of the left and right bucket cylinders 17 is gradually reduced to the target speed. Lowering, after passing of the deceleration region H is maintained at the target speed.
Thereafter, when it is detected that the vertical swing angle θb of the bucket 15 has reached the rise restriction angle θbb or the drop restriction angle θbd, the left and right bucket cylinders 17 are automatically stopped, and the vertical swing angle θb of the bucket 15 is The rising restriction angle θbb or the falling restriction angle θbd is maintained.

  As a result, in the ground angle maintenance control, the relief valve provided in the valve unit 20 is activated due to the fact that the vertical swing angle θb of the bucket 15 reaches the rising limit angle θba or the falling limit angle θbc. It is possible to prevent the occurrence of inconveniences such as a decrease in the amount of oil supplied to the boom cylinder 16 and a decrease in the driving speed of the boom 12 or an increase in the oil temperature.

  Further, by gradually reducing the operating speed of the left and right bucket cylinders 17 before the automatic stop, it is possible to suppress the occurrence of a shock at the time of automatic stop, and at the same time, the bucket of the bucket at the rising restriction angle θbb or the falling restriction angle θbd Stop accuracy can be increased.

  Although illustration is omitted, in the storage unit 24, the up-and-down swing angle θa of the boom 12, the rising restriction angle θcb set smaller than the rising limit angle θca with respect to the ground swinging angle θc of the bucket 15, and the bucket 15 Is stored with relational data indicating the relationship between the descent restriction angle θcd set larger than the descent limit angle θcc with respect to the ground swing angle θc and the boom angle detector 18 based on the relational data and the output of the boom angle detector 18. A setting unit for setting the rising restriction angle θcb and the lowering restriction angle θcd of the bucket 15 according to the vertical swing angle θa of 12 is provided, and the ground angle maintenance control unit 26 outputs the grounding of the bucket 15 output by the calculation unit 23 Based on the swing angle θc and the output of the setting unit, it is detected that the ground swing angle θc of the bucket 15 has reached the rise restriction angle θcb or the drop restriction angle θcd. In this case, the left and right bucket cylinders 17 may be configured to automatically stop.

  [Another embodiment]

[1] The traveling vehicle body A may be a dedicated vehicle for loader work, a loader mowing combined vehicle equipped with a front loader and a mower, a loader excavation combined vehicle equipped with a front loader and a backhoe, and the like.

[2] A hydraulic motor or the like may be employed as the boom actuator 16 and the bucket actuator 17.

[3] As the command operation tool 32, a command operation tool dedicated to the boom and a command operation tool dedicated to the bucket may be provided. Further, as the command operating tool 30, a switch for instructing the upward swing of the boom 12, a switch for instructing a downward swing of the boom 12, a switch for instructing a scooping swing of the bucket 15, and a dump swing of the bucket 15 You may make it provide the switch to command.

[4] As the boom angle detector 18, a sliding potentiometer that detects the expansion / contraction length of the boom cylinder 16 as the vertical swing angle θa of the boom 12 may be adopted. The bucket angle detector 19 may be a sliding potentiometer that detects the expansion / contraction length of the bucket cylinder 17 as the vertical swing angle θb of the bucket 15.

[5] The ground angle maintenance control unit 26 does not perform the control operation on the bucket actuator 17. The set angle from the rising restriction angle θao of the boom 12 has a problem in maintaining the ground swing angle θc of the bucket 15 constant. Various modifications are possible within the range. For example, the set angle may be set to 3 degrees or 4 degrees.

  The present invention can be applied to a front loader installed in a traveling vehicle body such as a tractor.

DESCRIPTION OF SYMBOLS 11 1st spindle 12 Boom 13 2nd spindle 15 Bucket 16 Boom actuator 17 Bucket actuator 18 Boom angle detector 19 Bucket angle detector 22 Manual control part 23 Calculation part 26 Ground angle maintenance control part 32 Command operation tool A Traveling vehicle body θa Boom vertical swing angle θb Bucket vertical swing angle θc Bucket ground swing angle

Claims (1)

An actuator for a boom that swings up and down in a vertical direction with a first support shaft that is horizontally oriented with respect to the traveling vehicle body as a fulcrum;
A bucket actuator that swings the bucket up and down around a second support shaft that is laterally oriented with respect to the boom; and
A boom angle detector for detecting a vertical swing angle of the boom;
A bucket angle detector for detecting a vertical swing angle of the bucket with respect to the boom;
A calculation unit for calculating a ground swing angle of the bucket based on an output of the boom angle detector and an output of the bucket angle detector;
A manual control unit for controlling the operation of the boom actuator and the bucket actuator based on an operation command output by the command operation tool;
A ground angle maintenance control unit that controls the operation of the bucket actuator so that the bucket ground swing angle is constant regardless of the boom swinging up and down based on the output of the arithmetic unit;
With
The ground angle maintenance control unit
Determining whether or not the boom swinging angle when the boom is stopped is within a set angle from the boom lifting restriction angle;
When the command operating tool outputs a boom lowering operation command, the manual control unit precedes the lowering control operation for the boom actuator based on the operation command regardless of the determination result. Start the control operation for raising the bucket actuator,
When the command operation tool outputs an operation command for raising the boom,
When the determination result is outside the set angle, the control for lowering the bucket actuator is started prior to the manual control unit starting the control operation for raising the boom actuator based on the operation command. Start working,
A front loader configured not to perform a control operation on the bucket actuator when the determination result is within a set angle.

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