JP3498751B2 - Control device for hydraulic excavator for side excavation - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for a hydraulic excavator for side excavation in which a side excavation attachment is mounted on the front portion of a vehicle body.

[0002]

2. Description of the Related Art FIG. 4 is a plan view of a conventional side excavating hydraulic excavator. In the figure, 1 is an undercarriage, 2
Is an upper revolving structure, 3 is a ditch attachment attached to the front portion of the upper revolving structure 2, 4 is a rear boom of the ditch attachment 3, 5 is a front boom, 6 is an upper boom, 7 is an arm, 8 is a bucket, 9 Is a boom cylinder, 10 is an offset cylinder, 11 is an arm cylinder, and 12 is a bucket cylinder. FIG. 5 is a hydraulic circuit diagram of the side excavation hydraulic excavator in FIG. 4. In the figure, 13 is an offset pilot switching valve for controlling the offset cylinder (10), 14 is an offset hydraulic remote control valve, and 15L and 15R are left and right traveling motors 16.
Switching valves for controlling L and 16R, 17 for boom pilot switching valve, 18 for bucket pilot switching valve, 19 for arm pilot switching valve, 20 for swing motor (21) control swing pilot switch Valve, 2
2 and 23 are variable capacity type first and second pumps, 2 respectively
Reference numeral 4 is a constant capacity third pump, 25 is an oil tank, 26 is a pilot pump, 27L and 27R are left and right working hydraulic remote control valves, and 28 is a high pressure selection of pilot pressure derived from the hydraulic remote control valves 27L and 27R. Shuttle valve to do, 2
9L and 29R are sub-valves of the traveling switching valves 15L and 15R, respectively, 30 is a supplementary pilot switching valve, and 31.
L and 31R are left and right traveling relief valves, 32 is a working relief valve arranged in the operating circuit of the boom cylinder 9 and the bucket cylinder 10, and 33 is an arm cylinder 11.
It is a work relief valve arranged in the operating circuit of.
The symbols E, Lolo, Haha, ..., Cheech are hydraulic remote control valves 27L, 27R and pilot switching valve 17, ...,
20 shows the connection of the pilot line connecting with 20.

When the side excavation hydraulic excavator is operated to perform the side excavation, the offset hydraulic remote controller 14 is operated to offset the bucket 8. That is, when the offset hydraulic remote control valve 14 is operated in the direction of the arrow L, the pilot pressure from the pilot pump 26 becomes the pipelines 34, 35, the pilot valve 36, and the pilot secondary pressure derived from the pilot valve 36. It acts on the pilot port 38 of the offset pilot switching valve 13 via the line 37. Since the pilot switching valve for offset 13 is switched from the neutral position to the le position, the pressure oil from the third pump 24 passes through the pipe 39, the le position of the pilot switching valve for offset 13 and the pipe 40, and then the offset cylinder 10 Is supplied to the rod side oil chamber 41. At the same time, the return oil from the bottom oil chamber 42 of the offset cylinder 10 is returned to the oil tank 25 via the offset position of the offset pilot switching valve 13. As a result, the offset cylinder 10 is contracted, and the bucket 8 can be offset-moved to the left side in plan view shown in FIG. Conversely, when the offset hydraulic remote control valve 14 is operated in the direction of arrow N, the offset pilot switching valve 13 is switched to the off position, and the offset cylinder 10 is extended. Therefore, in this case, the bucket 8 can be offset-moved to the right side in plan view shown in FIG. Then, when the offset cylinder 10 is maximally extended, it can be maximally offset moved by the dimension WR to the right centering on the longitudinal centerline 0-0 ′ of the rear boom 4. Further, when the offset cylinder 10 is contracted to the minimum, the front-rear center line 0-0 ′ of the rear boom 4 is
It is possible to make a maximum offset movement by the dimension WL to the left around the center.

[0004]

Since the structure of the side digging attachment is constituted by parallel links, if the offset amount of the bucket is increased, the strength of the structure decreases and the balance of the vehicle body becomes unstable. . In the conventional hydraulic excavator for side excavation, the excavation operation speed of the side excavation attachment did not change even when the offset amount was increased. Therefore, when excavating the side with high accuracy by increasing the offset amount, in addition to the strength problem of the above structure, fine operation is difficult and operability is poor. The present invention aims to solve the above problems.

[0005]

In a controller for a hydraulic excavator for side excavation having an attachment provided with an offset mechanism, an angle detection means for detecting an offset angle of the attachment and an offset detected by the angle detection means. An angle amount judging means for judging the magnitude of the angle and a maximum rotation speed changing means for changing the excavation operation speed of the attachment according to the magnitude of the offset angle judged by the angle amount judging means are provided. Furthermore, the maximum rotation speed changing means reduces the excavation operation speed of the attachment as the offset angle increases. Alternatively, the size of the offset angle of the attachment is detected by the angle range storage unit that presets and stores the size of the front center angle range where the offset angle is small and the oblique front angle range where the offset angle is large, and this angle detection unit. An offset angle matching means for matching the offset angle with each of the angle areas stored in the angle area storage means, and the offset angle matched by the offset angle matching means is maximum only when in the oblique front angle area. The excavation operation speed of the attachment is reduced by the rotation speed changing means.

[0006]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 is a plan view of a side excavation hydraulic excavator according to the present invention. In the figure, the same reference numerals are given to those using the same constituent elements as those in the prior art. 2'is an upper swing body, 3'is a side digging attachment, 4'is a rear boom, and 43 is an angle sensor which is an angle detecting means attached to the tip of the rear boom 4 '. It should be noted that the angle AL is the maximum leftward turning angle formed by the front-rear centerline 0-0 'of the rear boom 4'and the front-rear centerline of the front boom 5 when the bucket 8 is maximally offset to the left. The angle AR is the maximum right rotation angle formed by the front-rear centerline 0-0 'of the rear boom 4'and the front-rear centerline of the front boom 5 when the bucket 8 is maximally offset to the right.

FIG. 2 is a circuit diagram of a main part equipped in the hydraulic excavator for lateral side excavation of the present invention. In the figure, the same components as those in the conventional technique in FIG. 44 and 45 are regulators of the first pump 22 and the second pump 23, 46 and 47 are pilot ports for maximum flow rate cut control of the regulators 44 and 45, 48 is an electromagnetic switching valve, 49 is a solenoid of the electromagnetic switching valve 48, Reference numeral 50 is a controller (angle amount determination means, angle area storage means, offset angle comparison means).

Next, the construction of the hydraulic excavator for side edge excavation of the present invention will be described with reference to FIGS. In the present invention, the boom cylinder 9 and the bucket cylinder 12 of the side digging attachment 3'are driven by the variable displacement first pump 22, and the arm cylinder 11 is driven by the variable displacement second pump 23. The pump 26 and the regulators (44, 44) for the first and second pumps (22, 23).
45) The maximum flow rate cut control pilot ports 46 and 47 are connected via an electromagnetic switching valve 48, and a solenoid 49 of the electromagnetic switching valve 48 and an angle sensor 43 attached to the tip of the rear boom 4 '. Is connected via the controller 50, and based on the detection signal from the angle sensor 43, the controller 50 outputs a command signal to the electromagnetic switching valve 48 which is the maximum rotation speed changing means.

Next, the operation of the hydraulic excavator for lateral side excavation of the present invention will be described. Hydraulic remote control valve for offset 14
By operating, the offset cylinder 10 expands and contracts through the offset pilot switching valve 13. Accordingly, the front boom 5 rotates leftward or rightward around the vertical pin 51 (shown in FIG. 1) pivotally attached to the tip of the rear boom (4 ′). The rotation angle of the front boom 5 is detected by the angle sensor 43, and the detection signal is input to the controller 50.
When the front boom 5 is detected in the front central angle range a, the a range detection signal is sent to the controller 50.
Entered in. The controller 50 makes a determination based on the a-region detection signal and does not output a switching command signal to the electromagnetic switching valve 48. That is, since the solenoid 49 is in the non-energized state and the electromagnetic switching valve 48 is in the tank communication oil passage position Y, the pilot pressure from the pilot pump 26 does not act on the regulators 44 and 45. Therefore, if the engine (52 shown in FIG. 1) rotation is increased to a predetermined high speed rotation,
The first pump 22 and the second pump 23 discharge a predetermined maximum flow rate. Therefore, the work efficiency can be increased by increasing the excavation operation speed of the side digging attachment 3'as in the conventional case.

Next, when the front boom 5 is detected to be in the left oblique front angle range b or the right oblique front angle range C when the offset cylinder 10 is operated, the b and c area detection signals are input to the controller 50. To be done. Controller 5
At 0, the determination is made based on the b and c region detection signals, and a switching command signal is output to the electromagnetic switching valve 48. Then, the solenoid 49 is energized and the electromagnetic switching valve 48 is switched from the tank communication oil passage position Y to the opening oil passage position. The pilot pressure from the pilot pump 26 is applied to the throttle portion 53, the pipe lines 54, 5
5, the electromagnetic switching valve 48 passes through the line 56 and the line 56, one of which is introduced into the pilot port 46 through the line 57, and the other of which is branched at the line 56 and through the line 58, the pilot port. Introduced in 47. As a result, the regulators 44 and 45 operate, and the maximum flow rate Qmax of the first pump 22 and the second pump 23 is reduced to the predetermined cut flow rate Qcu.
can be reduced to t. Note that FIG. 3 is a PQ showing the maximum flow rate cut control of the first and second pumps (22, 23).
Although it is a diagram, the so-called FC mode (fine control mode) operation of the side digging attachment 3 ′ can be performed by reducing the pump discharge flow rate by a predetermined ratio in this way.

[0011]

When excavating the front central angle range of the side excavation hydraulic excavator with a small offset amount of the side excavation attachment, the excavation operation speed of the side excavation attachment is increased to improve work efficiency. Can be raised. When the offset amount of the side digging attachment is increased to excavate the oblique front angle range of the hydraulic excavator for side digging, the digging operation speed is reduced to improve the fine operability and the side digging attachment is impossible. It is possible to prevent a large load from acting.

[Brief description of drawings]

FIG. 1 is a plan view of a side excavating hydraulic excavator according to the present invention.

FIG. 2 is a circuit diagram of a main part equipped in the hydraulic excavator for lateral side excavation of the present invention.

FIG. 3 is a PQ diagram showing the maximum flow rate cut of the hydraulic pump.

FIG. 4 is a plan view of a conventional side excavating hydraulic excavator.

5 is a hydraulic circuit diagram of the side excavation hydraulic excavator in FIG. 4. FIG.

[Explanation of symbols]

3,3 'Side digging attachment 4,4 'rear boom 5 front boom 8 buckets 9 Boom cylinder 11 arm cylinder 12 bucket cylinders 22 1st pump 23 Second pump 26 Pilot pump 43 Angle sensor 44, 45 regulator 46,47 Pilot port 48 Solenoid switching valve 50 controller

Claims (3)

(57) [Claims] 1. A control device for a hydraulic excavator for side excavation having an attachment having an offset mechanism, comprising: angle detection means for detecting an offset angle of the attachment; and a size of the offset angle detected by the angle detection means. And a maximum rotation speed changing means for changing the excavation operation speed of the attachment according to the magnitude of the offset angle judged by the angle quantity judging means. Control device for hydraulic excavator for side excavation. 2. The maximum rotation speed changing means controls the attachment as the offset angle increases.
The control device for the hydraulic excavator for side excavation according to claim 1, wherein the excavation operation speed is reduced. 3. The angle range storage means for presetting and storing the magnitude of the offset angle of the attachment in a front center angle range having a small offset angle and an oblique front angle range having a large offset angle, and the angle detecting means. An offset angle matching means for matching the detected offset angle with each of the angle areas stored in the angle area storage means, and only when the offset angle matched by the offset angle matching means is in the oblique front angle area. The control apparatus for a hydraulic excavator for side excavation according to claim 2, wherein the excavation operation speed of the attachment is reduced by the maximum rotation speed changing means .