JPS5891233A - Control on bucket of loading shovel - Google Patents

Abstract

PURPOSE:To prevent damage to bucket of a loading shovel by a method in which when the angle of the bucket becomes more than a set value during the arm retraction period, a bucket cylinder is shrunk according to the angular velocity of the arm and the speed is corrected on the difference betweeen the angle of the bucket and the set angle of the bucket. CONSTITUTION:A loading shovel is provided with a boom 2 operated in a tilting manner by a boom cylinder pivotally attached to the machine body 1, an arm 3 operated in a rocking manner by an arm cylinder pivotally attached to the tip of the boom 2, and a bucket 4 turned by a bucket cylinder 7 pivotally attached to the arm 3 and also to the boom 2 at its one end. When the bucket 4 is not operated manually and the bucket angle GAMMA is more than a set angle GAMMAmax, the bucket cylinder 7 is contracted at a speed corresponding to the angular velocity B of the arm, and the contracting amount of the bucket cylinder 7 is corrected on the difference between the bucket angle and the set angle GAMMAmax.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a packet control method for a loading shovel having a packet pivoted by a packet cylinder whose one end is pivotally attached to a boom.

FIG. 1 is a diagram showing a loading shovel.

In the figure, 1 is the excavator main body, 2 is a boom that is pivotally attached to the main body 1, 3 is an arm that is pivoted to the tip of the boom 2, 4 is a packet that is pivoted to the tip of the arm 3, and 5 is the boom 2 that is tilted up and down. 6 is an arm cylinder that swings the arm 3; 7 is a packet cylinder that rotates the back and 4; one end of the packet cylinder 7 is pivotally connected to the boom 2; 8 is a packet cylinder with one end pivoted to the boom 2; 7 and the other end is pivotally connected to the arm 3, and the boom 2. Arm 3. Baku, Toshiling 7. Baku and Drink 8 form a pseudo-parallel link.

In this loading excavator, when the arm cylinder 6 is extended and the arm 3 is pushed out, the absolute angle θ of the packet 4 with respect to the ground surface is almost constant due to the above-mentioned pseudo-parallel link. There is no need to manipulate packet 4 at times. However, as shown in FIG. 2, even when the arm cylinder 6 is retracted and the arm 3 is retracted, the absolute angle θ of the packet 4 is kept constant. As the angle F increases, packet 4 finally reaches arm 3.
When the arm 3 is pulled in further, the pressure oil in the packet cylinder 7 is released, and the packet 4 is pressed against the arm 3 with a strong force, so that the arm 3. There is a risk that the back and front 4 may be damaged. In order to avoid this, the packet 4 may be operated to the dump side when the arm 3 is retracted, but in this case, it is necessary to operate the arm 3 and the packet 4 at the same time, making the operation cumbersome.

This invention has been made in order to solve the above-mentioned problems, and provides a packet control method for a loading shovel in which the packets do not hit the arm when the arm is retracted without the need for the back-up operation. With the goal.

In order to achieve this objective, in the present invention, when the packet angle exceeds a predetermined set angle,
The back cylinder is reduced at a speed corresponding to the arm angular velocity, and the amount of reduction of the packet cylinder is corrected according to the difference between the back angle and the set angle.

FIG. 3 is a diagram showing an apparatus for implementing the loading shovel packet control method according to the present invention. In the figure, 9 is a hydraulic pump, 10 is a pyro installed between the hydraulic pump 9 and the cylinder 7, and a directional switching valve 11 is a pyro that controls the directional switching valve 10, and a pilot operation that outputs pressure. Valve 12 is a pyro-operated valve 11
13 is the arm operation lever, 14.15 is the operation lever 12, respectively.
．． 13 is a lever operation detector that detects the operation state; 17 is a packet angle detector that outputs a packet angle signal γ corresponding to the packet angle F; and 18 is a packet angle detector that outputs a packet angle signal γ corresponding to the packet angle F;
The setting angle FID is determined so that the arm 3 does not hit the arm 3.
a signal generator that outputs a set angle signal γ according to ax, 2
5 is a comparator that compares the signal γ and the signal ax signal γ, and sends a signal to the control command device ax device 16 (description will be described later) when γ≧γmax; , a control command device ax which outputs a control signal A when the packet operation lever 12 is in the neutral position and a signal is output from the comparator 25 (when γ≧1); An adder/subtractor 20 calculates the difference between the signals Δγ and Δγ, and outputs the signal Δr when the signal Δγ is positive.
26 is an arm angle detector that outputs an arm angle signal β corresponding to arm angle B, 27 is a differentiator that differentiates the signal β and outputs an arm angular velocity signal β, and 28 is a signal whose packet 4 is A converter 29 calculates a speed signal y corresponding to the speed of the packet cylinder 7 when it rotates clockwise in FIG. 4 at an angular velocity corresponding to i, and 29 adds Δγ and signal y to the signal. 21 is an amplifier that amplifies and compensates for Δγ in the signal y+; 22 is a switch provided between the adder 29 and the amplifier 21; the switch 22 is turned on when the control signal A is output. 23 is an electro-hydraulic converter that outputs the pressure according to the output signal of the amplifier 21; 24 is the pilot pressure of the pilot operating valve 11; Among them, the one with high pressure,
) is a shuttle valve that selectively applies pressure to the directional control valve 10.

In this device, when the Nokukerato operation lever ζ-12 is operated, the pilot operation valve 11 and the directional control valve 10 are switched by the pilot pressure, and the Kukerato cylinder 7 is operated. ; Rotate. Also, when the arm operation lever (-13) is set to the arm retraction operation position, the arm 3 is retracted (・ki1 signal γ increases,
When the signal γ is smaller than the signal γmax, the control command device 16 does not output the control signal A, so the switch 22 is off, so the cylinder 7 does not operate.
. Then, when the signal γ becomes larger than the signal r, Zheng J
The control signal A is output from the control device ax 16, the switch 22 is turned on, and the packet cylinder 7 receives the signal y + kΔγ.
Shrink the image at a speed appropriate to the size. In this case, the packet 4 is rotated counterclockwise in FIG. 4 by the pseudo-parallel link at an angular velocity approximately equal to the arm angular velocity, and clockwise in FIG. 4 by the packet cylinder 7 at an angular velocity approximately equal to the arm angular velocity. Since it is rotated, the packet cylinder 7
The rotation caused by the pseudo-parallel link is canceled by the reduction of
Further, since the signal Δγ is controlled to be zero, the packet angle F is automatically maintained at the set angle F 2 , so the ax packet 4 will not hit the arm 3 . In this state, when the packet operation lever 12 is operated, the control signal A is no longer output from the control command device 16, and the switch 22
is turned off, so the packet 4 is turned off by the packet control lever 1.
It rotates at an angular velocity according to the amount of operation in step 2.

That is, in the packet control method for a loading shovel according to the present invention, when the arm 3 is retracted and the packet 4 is not manually operated, the setting angle rma
When the speed exceeds x, the speed corresponds to the arm angular speed)
(This is because the bucket angle limit control is performed to correct the reduction amount of the packet cylinder 7 according to the difference between the packet angle F and the set angle Fmax.)
Since it is held at aX, it does not hit the Kerato 4 force t-arm 3.

In the above-mentioned embodiment, when the bow 1 retracting operation of the arm 3 is performed and) (when the manual operation of the kerato 4 is not performed) (the kerato angle limiting control is performed), but when the arm 3 is retracted, When &m, manual operation of packet 4 is performed (regardless of force or effort), angle restriction control may be performed.In this case, -12ttf:/If you set it to the operating position,
The kerato 4 rotates at an angular velocity corresponding to the pilot pressure of the pilot control valve 11 and the pilot pressure of the electro-hydraulic converter 23, whichever is higher, and the packet control valve 12 is rotated. When the tilt operation position is set, the packet 4 rotates at an angular velocity corresponding to the difference between the pilot pressure of the pilot operation valve 11 and the pilot pressure of the electro-hydraulic converter 23. Although the packet angle control was performed when the arm was retracted, the bucket angle limit control may also be performed when the arm was not operated. In this case, the signal λ is zero, and the manual operation of packet 4 is carried out,
When the packet angle F exceeds the set angle F by ax, the signal Δγ is output, so the packet cylinder 7 contracts at a speed corresponding to the signal Δγ.
The packet angle r is held at the set angle rmax, and packet 4
can be prevented from hitting the arm 3. Furthermore, in the above-mentioned embodiment, the amount of operation of the backward and forward operating levers 12 is converted into oil pressure, but the amount of operation of the packet operating lever 12 is electrically detected, and Δr is switched or added to this signal and the signal y+. The directional control valve lO may be controlled by a pilot pressure corresponding to the signal. Further, in the earth excavation embodiment, a pyro-type valve 10 is used, but an electromagnetic type valve 10 may also be used.

Furthermore, a directional switching valve for automatic control may be provided separately from the directional switching valve for manual operation, and the directional switching △ valve for automatic control may be switched to the signal y+ by an amount corresponding to Δγ (・0
Further, in the above embodiment, the directional control valve 10 was used as a means for controlling the speed of the cylinder.
The speed of the packet cylinder 7 may be controlled by the discharge amount of the variable displacement hydraulic pump (.Furthermore, the calculation section may be constructed of an analog circuit or a digital circuit such as a microcomputer. Especially, When controlling the absolute angle θ of the packet 4 to be kept constant using a microcomputer, the present invention can be implemented by simply adding a small amount of software.

As explained above, in the packet control method for a loading excavator according to the present invention, - When the arm is retracted, the packet can hit the arm without any manipulation of the packet. There is no risk of damage to the material.As described above, the effects of the present invention are remarkable.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a loading shovel, FIG. 2 is an explanatory diagram of the operation of the loading shovel, and FIG. 3, FIG. 4 is a diagram showing a device for implementing the bucket control method for a loading shovel according to the present invention. 1... Excavator body 2... Boom 3... Arm 4... Packet 5... Boom cylinder 6... Arm cylinder 7... Packet cylinder 8... Packet link 9... Hydraulic pump
10...Directional switching valve 11...Pilot operating valve 12...Packet operating lever 13...Arm operating lever 14.15...Lever operation detector 16...Control command device 17...Packet Angle detector 18...signal generator 19...addition/subtraction device 20
...Coefficient unit 21...Amplifier 22...Switch 23...Electrohydraulic converter 24...Shuttle valve 25...Comparator 26...Arm angle detector 27...Differentiator 28 ...Converter 2
9... Adder skill 1 Figure 4-2 Figure 3 Hand 1

Claims (1)

[Scope of Claims] (11) A boom that is pivotally attached to the main body and is moved up and down by a poom cylinder; - An arm that is pivoted to the tip of the boom and is swung by an arm cylinder; In the above-described fast control method for a loading shovel having a packet rotated by a packet cylinder whose one end is pivotally connected to the boom, when the bucket angle becomes equal to or larger than a predetermined set angle, Loading characterized in that the packet cylinder is contracted at a speed according to the arm angular velocity, and back and back angle limit control is performed to correct the amount of reduction of the packet cylinder according to the difference between the bucket angle and the set angle. Packet control method for an excavator. (2) The bucket angle limit control is performed when the arm is retracted and the bar actuator is not manually operated. Packet control method for loading excavators.