JPH0881980A - Backhoe - Google Patents

Abstract

PURPOSE: To keep the deceleration characteristics of a hydraulic cylinder in a restraint region constant by changing operation characteristics to the neutral stop side of a hydraulic-cylinder control valve on the small flow rate side of a pump and the operation characteristics to the small flow rate side on the large flow rate side of the pump. CONSTITUTION: When a bucket 6 enters restraint regions B1, B2, a control valve for a backhoe device 3 works to the neutral stop side with approach to restraint surfaces A1, A2 of the bucket 6. The operating speed of a hydraulic cylinder for driving the device 3 is decelerated, and the bucket 6 reaches the restraint surfaces A1, A2, and the hydraulic cylinder is stopped. The flow rate of a hydraulic fluid to the hydraulic cylinder is changed as compared to the opening of the control valve by the magnitude of the flow rate of the hydraulic fluid from a pump at that time, and fast or slow operating speed is decided. Consequently, the operation characteristics of the control valve in the restraint region B1 are varied to the small or large flow rate side respectively by the magnitude of the flow rate of the pump. Accordingly, the hydraulic cylinder is decelerated by constant characteristics in the restraint region B1 regardless of the magnitude of the flow rate of the hydraulic fluid from the pump.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a backhoe structure for avoiding contact between an outer frame covering a driving part and a bucket of a backhoe device.

[0002]

2. Description of the Related Art In the backhoe as described above, an example of a structure for avoiding contact between an external frame and a bucket is disclosed in Japanese Patent Laid-Open No. 6-2345. In this structure, an external frame that covers the driving part (see FIG.
And a check surface (A1, A2 in FIG. 3 and FIG. 4 of the above-mentioned publication) separated from the check surface by a predetermined distance outward from the check surface by a predetermined distance. A check area (B1 and B2 in FIGS. 3 and 4 of the above publication) is set between the surface of the distant space and the check surface.

As a result, a position sensor for detecting the position of the bucket of the backhoe device (3 in FIG. 6 of the above publication).
6, 37, 38) are provided, the control valve of the hydraulic cylinder for driving the backhoe device is operated to the neutral stop position side when the bucket enters the check area, and the closer the bucket approaches the check surface in the check area, The operating speed of the hydraulic cylinder is greatly reduced. When the bucket reaches the check surface and tries to enter the operation unit side beyond the check surface, the control valve is operated to the neutral stop position to stop the hydraulic cylinder and prevent the check. With the above configuration, if the operator of the driving section is operating the backhoe, and if the operator accidentally moves the bucket closer to the driving section, the bucket (hydraulic cylinder) will automatically decelerate. The bucket (hydraulic cylinder) is automatically stopped when the bucket reaches the check surface outside the outer frame, and contact is avoided.

[0004]

In the above structure, when the bucket enters the restraint region, the control valve is operated to the neutral stop position side to suppress the flow rate of the hydraulic oil to the hydraulic cylinder, thereby decelerating the hydraulic cylinder. are doing. in this case,
The pump is driven by the engine mounted on the backhoe,
The hydraulic oil from the pump is supplied to the hydraulic cylinder via the control valve, and if the engine speed changes, the flow rate of the hydraulic oil supplied from the pump to the control valve also changes.

Therefore, if the control valve is always operated to the neutral stop position side with the same characteristics when the bucket enters the restraint region, the control valve operates when the flow rate of the hydraulic oil from the pump is small. The action of the deceleration operation becomes strong, and the bucket (hydraulic cylinder) may stop in the restraining area even though it has not reached the restraining surface. On the contrary, when the flow rate of the hydraulic oil from the pump is large, the action of the deceleration operation by the control valve is weakened, and the bucket (hydraulic cylinder) does not sufficiently decelerate even though it reaches just before the check surface,
When the bucket (hydraulic cylinder) reaches the check surface, it suddenly stops and a shock may occur.
An object of the present invention is to make a deceleration operation of a bucket (hydraulic cylinder) always performed in a constant state when the bucket enters the restraint region, regardless of the engine speed.

[0006]

A feature of the present invention is that the backhoe as described above is configured as follows. That is, an artificial operation tool that is operated manually, a hydraulic cylinder that drives and operates the backhoe device, a control valve that supplies and discharges hydraulic oil from a pump that is driven by an engine to the hydraulic cylinder, and an operation of the artificial operation tool. A control device for operating a control valve based on the above, and a first setting means for setting a check surface in the space that is away from the external frame covering the operating part provided on the swivel by a predetermined distance, and a check surface. A position sensor for detecting the position of the bucket of the backhoe device, and a second setting means for setting a check area between a surface of the space and a check surface that are away from the outside by a predetermined distance. When the bucket enters the restraint area based on the control valve, the control valve is operated to the neutral stop position side, and the deceleration means for decelerating the operating speed of the hydraulic cylinder as the bucket approaches the restraint surface. When the control valve reaches the check surface and tries to enter the operation part side beyond the check surface, the control valve is operated to the neutral stop position, and the check means for stopping the hydraulic cylinder to prevent the check is provided and the pump from the pump is also provided. Equipped with a flow rate sensor that detects the flow rate of hydraulic oil. If the detected value of the flow rate sensor is on the small flow rate side, the operation characteristic of the control valve to the neutral stop position side by the deceleration means is changed to the large flow rate side as a whole. However, when the detected value of the flow rate sensor is on the high flow rate side, a change means for changing the operation characteristic to the low flow rate side as a whole is provided.

[0007]

With the construction of the present invention, for example, as shown in FIG. 3, when the bucket 6 enters the check regions B1 and B2,
The bucket 6 keeps the check surface A1, regardless of the operation of the manual operation tool.
The closer it is to A2, the control valve for the backhoe device is operated toward the neutral stop position side as shown in the operation characteristic F1 of FIG. 2, and the hydraulic cylinder (bucket 6) for driving the backhoe device is shown in FIG. The operating speed is greatly decelerated. Next, when the bucket 6 reaches the restraining surfaces A1 and A2, the bucket 6 is crossed over the restraining surfaces A1 and A2 and the bucket 6 is operated by the operating unit 27.
When the control valve is moved to the side, the control valve is operated to the neutral stop position, the hydraulic cylinder (bucket 6) is stopped, and such operation of the bucket 6 is blocked.

When the flow rate of the hydraulic oil from the pump is large in the above state, the flow rate of the hydraulic oil to the hydraulic cylinder is large relative to the opening degree of the control valve, and the operating speed of the hydraulic cylinder is high. I can judge. On the contrary, if the flow rate of the hydraulic oil from the pump is small, it can be determined that the flow rate of the hydraulic oil to the hydraulic cylinder is small for the opening degree of the control valve, and the operating speed of the hydraulic cylinder is low.

Therefore, in the configuration of the present invention, as shown in FIG. 2, for example, when the flow rate of the hydraulic oil from the pump is small, the operation characteristic F1 of the control valve in the check region B1 is the operation on the large flow side. When the flow rate of the hydraulic oil from the pump is large due to the change operation to the characteristic F2 as a whole, the operation characteristic F1 of the control valve in the check region B1 is changed to the operation characteristic F3 on the small flow side as a whole. It As a result, the hydraulic cylinder is decelerated with a constant characteristic E as shown in FIG. 1 in the restraint region B1 regardless of the flow rate of the hydraulic oil from the pump.

[0010]

As described above, in the backhoe in which the restraint region and the restraint surface are set in the space, the hydraulic cylinder is always provided with a constant characteristic in the restraint region regardless of the engine speed (the flow rate of the hydraulic oil from the pump). The deceleration operation can be performed by preventing the bucket (hydraulic cylinder) from stopping before the check surface, or preventing the bucket (hydraulic cylinder) from being fully decelerated even immediately before the check surface. As a result, the stability of the operation of the backhoe device can be improved.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. (1) FIG. 6 shows the entire side surface of a backhoe, in which a rubber crawler type traveling device 1 supports a dozer 20 and a swivel base 2 on an upper part thereof, and a backhoe device 3 is provided in front of the swivel base 2. . The backhoe device 3 is a hydraulic cylinder 11
It comprises a boom 4 which is oscillated by a hydraulic cylinder 12, an arm 5 which is oscillated by a hydraulic cylinder 12, and a bucket 6 which is oscillated by an hydraulic cylinder 13.
A hydraulic motor 14 is provided to drive the swivel base 2.

As shown in FIG. 6, the boom 4 of the backhoe device 3 has a first boom portion 4a connected to a swivel base 2 so as to be swingable up and down, and a left and right side around an axis P1 at the front end of the first boom portion 4a. A second boom portion 4b swingably connected to the
The support bracket 4c is swingably connected to the left and right around the axis P2 at the front end of the second boom portion 4b, and the arm 5 is connected to the support bracket 4c.
The linkage link 8 is laid across the first boom portion 4a and the support bracket 4c to form a parallel four-link.
By swinging the second boom portion 4b with the hydraulic cylinder 7, the arm 5 and the bucket 6 are moved in parallel to the left and right.

As shown in FIG. 7, a control valve 21 for the hydraulic cylinder 11 of the first boom portion 4a of the boom 4,
Hydraulic cylinder 7 of second boom portion 4b of boom 4
A control valve 25 for the hydraulic cylinder 12 of the arm 5, a control valve 23 for the hydraulic cylinder 13 of the bucket 6, and a control valve 24 for the hydraulic motor 14 of the swivel base 2. The control valves 21 to 25 are of three-position switching type and pilot operated type, and the flow rate can be controlled by adjusting the opening degree based on the pilot pressure. An electromagnetic proportional pressure reducing valve type pilot valve 31, 32, 3 for supplying a pilot pressure for operating the opening to each control valve 21-25
3, 34, 35 are provided. The hydraulic oil from the pump 43 driven by the engine 42 mounted on the swivel base 2 is supplied to the control valves 21 to 25, and the engine 4
The pilot hydraulic oil from the pilot pump 44 driven by 2 is supplied to the pilot valves 31 to 35.

As shown in FIGS. 7 and 5, a right operation lever 9 (corresponding to an artificial operation tool) and a left operation lever 1 are mounted on the swivel base 2.
0 (corresponding to an artificial operation tool) is provided. The right and left operation levers 9 and 10 can be operated forward, backward, left and right, and are provided with a potentiometer 15 for detecting the operation position of the right operation lever 9 in the front-rear direction and a potentiometer 16 for detecting the operation position in the left-right direction. A potentiometer 17 for detecting an operation position in the front-rear direction of 10 and a potentiometer 18 for detecting an operation position in the left-right direction are provided, and operation signals from the potentiometers 15 to 18 are input to the control device 19. An operation pedal 26 (corresponding to an artificial operation tool) is provided on the lower front side of the swivel base 2, and an operation signal from the operation pedal 26 is input to the control device 19.

With the above construction, when the right operation lever 9 is operated forward or backward, an operating current is supplied from the control device 19 to the pilot valve 31 based on this, and the pilot valve 35 is operated, so that the control valve 21 moves the first boom. When the portion 4a is operated to the descending side or the ascending side, and when it is operated to the right or left, the pilot valve 33 is operated based on this, and the control valve 23 is operated to the soil discharging side or the scraping side of the bucket 6. When the left operation lever 10 is operated forward or backward, an operation current is supplied from the control device 19 to the pilot valve 32 based on this, and the pilot valve 32 is operated, so that the control valve 22 is operated to the raising side or the scraping side of the arm 5. When operated to the right or left, the pilot valve 34 is operated based on this, and the control valve 2
4 is operated to the right turning side or the left turning side. Operating pedal 2
When 6 is stepped to the right or left, the control device 1 is based on this.
An operating current is supplied from 9 to the pilot valve 35 to operate the pilot valve 35, so that the control valve 25 moves the second boom portion 4
It is operated to the right or left swing side of b.

In the above operation, the potentiometers 15 to 18 for the right and left operation levers 9 and 10 detect not only the operation direction of the right and left operation levers 9 and 10 but also the operation amount from the neutral position thereof. There is. As a result, as the operation amount of the right and left operation levers 9 and 10 increases, the pilot pressure of the pilot valves 31 to 34 increases and the control valves 21 to 2 increase.
4 is operated to the high flow rate side. That is, the larger the right and left operating levers 9 and 10 are operated, the more hydraulic cylinders 11 to 1 are operated.
3 and the hydraulic motor 14 are configured to operate at high speed.

(2) Next, the front first and second front restraint surfaces A1 and A2 and the horizontal restraint surface A3 set for the operating unit 27 of the swivel base 2 will be described. As shown in FIG. 4 and FIG. 5, in the swivel base 2, the backhoe device 3 is arranged on the right side, and the driver's seat 28 and the driver 27 composed of the right and left operating levers 9 and 10 are arranged on the left side. . Figures 3,4
As shown in FIG. 5, a partition wall 29 (corresponding to an external frame) with a window for partitioning the backhoe device 3 and the operating unit 27 is provided at the center of the swivel base 2 at the upper end of the swivel base 2. A semi-circular roof portion 30 (corresponding to an external frame) along the outer side of is fixed.

As shown in FIGS. 6 and 7, a potentiometer 36 (corresponding to a position sensor) for detecting the vertical angle of the first boom portion 4a (boom 4) with respect to the swivel base 2, and a second boom for the first boom portion 4a. A potentiometer 37 (corresponding to a position sensor) that detects the left / right angle of the portion 4b, a potentiometer 38 (corresponding to a position sensor) that detects the longitudinal angle of the arm 5 with respect to the support bracket 4c, and a longitudinal angle of the bucket 6 with respect to the arm 5 are detected. A potentiometer 39 (corresponding to a position sensor) is provided, and the detection values of the potentiometers 36 to 39 are input to the control device 19.

As shown in FIGS. 3, 4 and 5, the partition wall 29 is located in a range above a predetermined position D above the swivel base 2.
The front first check surface A1 (corresponding to the check surface) having a predetermined left and right width apart from the front edge 29a of the front of the front edge 29a by a predetermined distance is set in the space (corresponding to the first setting means), and the front edge of the roof portion 30. Thirty
The front second check surface A2 (corresponding to the check surface), which is separated from the a by a predetermined distance forward and has a predetermined vertical width, is the front first check surface A1.
Are set in the space in series (corresponding to the first setting means). In a range above the predetermined position D, a surface which is separated from the front first and second front check surfaces A1 and A2 by a predetermined distance is set, and the surface of the space and the front first and second check surfaces A1 are set. , A2 are set as a front first check area B1 (corresponding to a check area) and a front second check area B2 (corresponding to a check area) (corresponding to a second setting unit).

As shown in FIGS. 5 and 4, a plane which is separated from the partition wall 29 to the right in the plane of FIG. 5 by a predetermined distance from the end of the front first check surface A1 on the backhoe device 3 side to the rear. A horizontal check surface A3 (corresponding to the check surface) is set in the space (corresponding to the first setting means). A plane separated from the horizontal restraint surface A3 by a predetermined distance to the right side of the paper surface of FIG. 5 is set, and a space between this plane and the horizontal restraint surface A3 is set as a horizontal restraint area B3 (corresponding to the restraint area). (Corresponding to the second setting means). The front first and second check surfaces A1, A as described above
2, front first and second check area B1, B2, lateral check surface A
3 and the lateral restraint area B3 are set in the space of the swivel base 2 and move together with the swivel base 2 as the swivel base 2 turns.

(3) Next, the predetermined position D in FIGS. 3 and 4 will be described. As shown in FIG. 3, the second boom portion 4b is operated by the hydraulic cylinder 7 so that the bucket 6 is located in front of the front edge 29a of the partition wall 29, and the arm 5 is scraped to the end of the working range. The bucket 6 is operated to the dumping side, and the tip of the bucket 6 and the arm 5 are operated.
In a state in which and are operated so as to form a straight line (the state in which the length from the arm 5 to the tip of the bucket 6 is the longest),
When the first boom portion 4a is operated upward, the bucket 6
The tip of is moving on the locus C.

In this case, the first boom portion 4 is in the above-mentioned state.
The position where the tip of the bucket 6 comes closest to the front edge 29a of the partition wall 29 when the a is operated to the upside is the predetermined position D, and the first boom portion 4a is crossed beyond the predetermined position D.
Is operated to the upside, the tip of the bucket 6 is moved to the partition wall 29.
The front edge 29a of the. On the contrary, even if the first boom portion 4a is operated to the descending side from the predetermined position D in the above-mentioned state, the tip of the bucket 6 does not contact the front edge 29a of the partition wall 29 and the swivel base 2.

(4) Next, the front first and second check surfaces A
1, A2, front first and second front restraint areas B1, B2 control of the backhoe device 3 will be described. In the control device 19, the vertical angle of the first boom portion 4a, the horizontal angle of the second boom portion 4b, the front-back angle of the arm 5 and the bucket 6, and the front and rear angles of the first boom portion 4a and the second boom portion 4a, which are detected by the potentiometers 36 to 39. The position of the tip of the bucket 6 is constantly detected by the lengths of the boom portion 4b, the arm 5, and the bucket 6, and the potentiometers 36 to 3 are used.
The moving direction and moving speed of the tip of the bucket 6 are detected by differentiating the detected value of 9.

When the tip of the bucket 6 is located in front of the front edges 29a, 30a of the partition wall 29 and the roof portion 30, the tip of the bucket 6 is located at the front first and second front portions of FIGS. When entering the restraint regions B1 and B2, regardless of the operation of the right and left operation levers 9 and 10 and the operation pedal 26,
As shown by the operating characteristic F1 in FIG. 2, the operating current from the control device 19 to the pilot valves 31, 32, 33, 35 is dropped, and the control valves 21, 22, 23, 25 are correspondingly moved to the neutral stop position side. To the hydraulic cylinders 7, 11, 12, 13 (bucket 6) as shown in the deceleration characteristic E of FIG.
The operating speed of is decelerated.

In this case, as shown in the deceleration characteristic E of FIG. 1 and the operation characteristic F1 of FIG. 2, the front end of the bucket 6 is located in the front first and second front check regions B1 and B2. 2 The closer to the check surfaces A1 and A2, the pilot valve 3
The operating currents to 1, 32, 33, 35 are continuously reduced, and the hydraulic cylinders 7, 11, 12, 13 (bucket 6)
The operating speed of is continuously decelerated (the above corresponds to the deceleration means). Conversely, when the first boom portion 4a or the like is operated in the direction in which the tip of the bucket 6 moves away from the front first and second front restraining surfaces A1 and A2 in the front first and second front restraining areas B1 and B2. Contrary to the deceleration operation described above, the operating speed of the hydraulic cylinders 7, 11, 12, 13 (bucket 6) is increased, and the front first and second front restraint regions B1, B
It returns to the original operating speed when exiting from 2.

Then, it is assumed that the tip of the bucket 6 reaches the front first check surface A1 or the second front check surface A2. in this case,
Even if the bucket 6 is operated on the side beyond the front first or second check surfaces A1 and A2 such as the operation of the arm 5 on the scraping side, the deceleration characteristic E of FIG. 1 and the operation characteristic of FIG. As shown in F1, the pilot valves 31, 32, 33, 3
The operating current to 5 becomes zero, the pilot pressure disappears, the control valves 21, 22, 23, 25 are operated to the neutral stop position,
The hydraulic cylinders 7, 11, 12, 13 (bucket 6) are stopped (the above is equivalent to the restraint means). On the contrary, when the tip of the bucket 6 reaches the front first or second front restraining surfaces A1 and A2, the tip of the bucket 6 moves to the front first or front second restraint, such as when the arm 5 is operated toward the raising side. The operation away from the surfaces A1 and A2 can be performed without any trouble.

The tip of the bucket 6 is the front edge 2 of the partition wall 29.
When the second boom portion 4b is operated by the hydraulic cylinder 7 to the left side (the driving unit 27 side) around the axis P1 of the first boom portion 4a in the state of being located in front of 9a,
If the tip of the bucket 6 does not touch the front first check surface A1,
The second boom portion 4b can be operated to the left side (driving section 27 side). This is because the side of the front first restraint surface A1 on the side of the operation unit 27 is a space where there is nothing that the tip of the bucket 6 contacts. Then, in the vicinity of the lower end of the front first restraint surface A1 (near the predetermined position D), the second boom portion 4
When b is operated to the left side (driving section 27 side), the bucket 6
4 is a guard frame 40 of the driving unit 27 (which is connected across the middle of the front edge 29a of the partition wall 29 and the swivel base 2) shown in FIGS. 4 and 5, and an operating lever 41 for the traveling device 1. Guard frame 4 to prevent contact with
The positions of 0 and the operation lever 41 are set.

In the above structure, as shown in FIG. 7, a rotation speed sensor 45 (corresponding to a flow rate sensor) for detecting the rotation speed of the engine 42 (pump 43, pilot pump 44) is provided. The detected value of is input to the control device 19. As a result, when the rotation speed of the engine 42 is high, the flow rate of the hydraulic oil (pilot hydraulic oil) from the pump 43 (pilot pump 44) is large, and the operating current to the pilot valves 31, 32, 33, 35 is relatively small. The flow rate of hydraulic oil to the hydraulic cylinders 7, 11, 12, 13 is large, and the hydraulic cylinders 7, 11, 12, 13
It can be determined that the operating speed of (bucket 6) is high. On the contrary, if the rotation speed of the engine 42 is low, the pump 43
The flow rate of the hydraulic oil (pilot hydraulic oil) from the (pilot pump 44) is small, and the pilot valves 31, 32, 3
The hydraulic cylinders 7, 11,
It can be determined that the flow rate of the hydraulic oil to 12 and 13 is small and the operating speed of the hydraulic cylinders 7, 11, 12 and 13 (bucket 6) is slow.

Therefore, as shown in FIG. 2, when the rotation speed of the engine 42 is low (corresponding to the small flow rate side), the operation characteristic F1 is entirely changed to the operation characteristic F2 side (large flow rate side), and the engine is changed. If the rotation speed of 42 is high (corresponding to the large flow rate side), the operation characteristic F1 is entirely changed to the operation characteristic F3 side (small flow rate side) (corresponding to a changing unit). As a result, the pilot valves 31, 32, 33 in the front first and second check regions B1, B2 are arranged in accordance with the rotational speed of the engine 42 (the flow rate of the hydraulic oil of the pump 43 and the pilot pump 44 and the flow rate of the pilot hydraulic oil). , 35 operating currents (opening of control valves 21, 22, 23, 25) operating characteristics F1, F
2 and F3 are automatically changed, the hydraulic cylinder 7, as shown in FIG. 1, in the front first and second front restraint regions B1 and B2 regardless of the rotation speed of the engine 42. A constant deceleration characteristic E of 11, 12, 13 (bucket 6) is obtained.

(5) Next, as shown in FIG.
In the state where the tip of is located below the predetermined position D,
As described above, when the bucket 6 is positioned in front of the front edge 29a of the partition wall 29, the tip of the bucket 6 moves on the locus C when the first boom portion 4a is operated up and down. The tip of the bucket 6 does not contact the front edge 29a of the partition wall 29 and the swivel base 2.

Then, in a state where the tip of the bucket 6 is located below the predetermined position D and located on the locus C,
Even if the second boom portion 4b is operated to the left or right by the hydraulic cylinder 7, the tip of the bucket 6 does not come into contact with the swivel base 2, the guard frame 40 of the driving unit 27, the operation lever 41 for the traveling device 1, or the like. . As described above, at the position below the predetermined position D, the tip of the bucket 6 is moved so that the tip of the bucket 6 does not come into contact with the swivel base 2 and the like, no matter how the backhoe device 3 is operated. Since the locus is set, the front first and second check surfaces A1 and A2, the front first and second check areas B1 and B2 as shown in FIGS. 3 and 4 are set.
Etc. are not set.

(6) Next, the control of the backhoe device 3 with respect to the lateral restraint surface A3 and the lateral restraint area B3 will be described. In the control device 19, similarly to the above, the vertical angle of the first boom portion 4a based on the detection values of the potentiometers 36 to 39, the horizontal angle of the second boom portion 4b, the longitudinal angle of the arm 5 and the bucket 6, and the first boom portion 4a. , The length of the second boom portion 4b, the arm 5 and the bucket 6,
The position of the left lateral surface of the bucket 6 is constantly detected, and the moving direction and the moving speed of the left lateral surface of the bucket 6 are detected by differentiating the detection values of the potentiometers 36 to 39.

As shown in FIGS. 4 and 5, when the bucket 6 is located on the right side of the operating unit 27, the second boom portion 4b is operated to the operating unit 27 side by the hydraulic cylinder 7, and the bucket 6 is moved. When the left lateral surface of the control valve enters the lateral restraint region B3, as shown in the deceleration characteristic E of FIG. 1 and the operation characteristics F1, F2, F3 of FIG. 35, the operating speed of the hydraulic cylinder 7 (bucket 6) of the second boom portion 4b is decelerated regardless of the operation of the operation pedal 26.
In this case, as the left lateral side surface of the bucket 6 enters the lateral restraint area B3 and approaches the lateral restraint surface A3, the deceleration operation is greatly performed (the above corresponds to the deceleration means). On the contrary, when the second boom portion 4b is operated in the direction in which the left lateral side surface of the bucket 6 is separated from the lateral restraint surface A3, the second boom portion 4b is moved within the lateral restraint area B3 contrary to the deceleration operation described above. The operating speed of the hydraulic cylinder 7 is increased, and returns to the original operating speed when it comes out of the lateral restraint region B3.

Next, the left lateral surface of the bucket 6 is a lateral restraint surface A.
3 is reached, and when it is about to be operated toward the operation unit 27 side beyond the lateral restraint surface A3, the deceleration characteristic E of FIG. 1 and the operation characteristic F of FIG. 2 are the same as in the case of (5) above.
1, F2, F3, the control device 19 operates the pilot valve 35 to the neutral stop position, the pilot pressure disappears, and the control valve 25 operates to stop the hydraulic cylinder 7 (bucket 6) of the second boom portion 4b. (The above is equivalent to the restraint means).

[Other Embodiment] In the above embodiment, the bucket 6 is used.
Although the front first and second front restraint surfaces A1 and A2 and the horizontal restraint surface A3 are set with reference to the tip and the left lateral surface of FIG.
The potentiometer 39 is omitted and the potentiometer 3
6, 37, 38 with the front end of the arm 5 (connection point of the bucket 6) as a reference, the front first and second front restraining surfaces A1, A
2, the lateral restraint surface A3 may be set. Instead of the partition wall 29 and the roof portion 30, a cabin (not shown) that covers the operation unit 27 in a substantially closed room may be provided in the swivel base 2 and this cabin may be used as an external frame.

In the above-described embodiment, the pilot operated type control valves 21 to 25 are operated via the electromagnetic proportional pressure reducing valve type pilot valves 31 to 35. Abolish and control valves 21-25
Is configured as an electromagnetic proportional pressure reducing valve type, the operating positions of the right and left operating levers 9 and 10 and the operation pedal 26 are electrically detected by potentiometers 15 to 18, and the electromagnetic proportional pressure reducing valve type of the electromagnetic proportional pressure reducing valve type is detected based on the detected values. The control valves 21 to 25 may be directly operated. In this case, the control valve 21
To the operating current to 25, the operating characteristics F1, F2, F of FIG.
It is configured to control based on 3. In the embodiment described above, the operating characteristics F1, F2, F3 in FIG. 2 are set by detecting the rotation speed of the engine 42.
The flow rate of the hydraulic oil from 3 may be directly detected by a flow rate sensor (not shown) to set the operation characteristics F1, F2, F3 of FIG.

It should be noted that reference numerals are added to the claims for convenience of comparison with the drawings, but the present invention is not limited to the structures of the accompanying drawings by the entry.

[Brief description of drawings]

FIG. 1 is a diagram showing a relationship between a bucket operating speed and a bucket position in a front first and second front restraint region and a lateral restraint region.

FIG. 2 is a diagram showing a relationship between an operation current to a pilot valve and a position of a bucket in the front first and second front restraint regions and the lateral restraint region.

FIG. 3 is a schematic side view of a backhoe showing front first and second check surfaces and front first and second check regions.

FIG. 4 is a schematic front view of a backhoe showing front first and second check surfaces, front first and second check areas, lateral check surfaces, and horizontal check areas.

FIG. 5 is a schematic plan view of a backhoe showing a front first check surface and a front first check area, a lateral check surface, and a horizontal check area.

FIG. 6 is an overall side view of the backhoe.

FIG. 7: Hydraulic cylinders for the backhoe device, control valves,
Diagram showing the relationship between the pilot valve, right and left operating levers, etc.

[Explanation of symbols]

 2 swivel base 3 backhoe device 6 buckets 7, 11, 12, 13 hydraulic cylinders 9, 10, 26 human operation tool 19 control device 21, 22, 23, 25 control valve 27 operating part 29, 30 external frame 36, 37, 38 , 39 Position sensor 42 Engine 43 Pump 45 Flow rate sensor A1, A2, A3 Check surface B1, B2, B3 Check area F1, F2, F3 Operating characteristics

Claims (1)

[Claims] 1. An artificial operation tool (9) which is artificially operated,
(10), (26) and hydraulic cylinders (7), (11), (12), (1 for driving and operating the backhoe device (3).
3) and a pump (43) driven by the engine (42)
From the hydraulic cylinders (7), (11),
Control valves (21) for supplying and discharging to (12) and (13),
(22), (23), (25) and the control valves (21), (22), (23), (25) based on the operation of the artificial operation tools (9), (10), (26). And a control device (19) for operating the control unit (19) for operating the control unit (19) for covering the operation unit (27) provided on the swivel base (2) and being separated from the external frames (29) and (30) by a predetermined distance outward. First setting means for setting (A1), (A2), (A3) in space, and the above-mentioned check surfaces (A1), (A2),
The areas of the space apart from (A3) by a predetermined distance and the check surfaces (A1), (A2), and (A3) are set as check areas (B1), (B2), and (B3). Position sensors (36), (37), (38), for detecting the position of the bucket (6) of the backhoe device (3), comprising second setting means.
(39) and the position sensors (36), (37),
The bucket (6) based on the detections of (38) and (39)
Enters the restraint regions (B1), (B2), (B3), the control valves (21), (22), (23), (2
5) is operated to the neutral stop position side to move the bucket (6)
Is closer to the check surfaces (A1), (A2), (A3), the hydraulic cylinders (7), (11), (12),
Deceleration means for greatly decelerating the operating speed of (13);
The bucket (6) has the check surfaces (A1), (A2),
(A3) is reached and the above-mentioned check surfaces (A1), (A2), (A
3), when trying to enter the operation unit (27) side, the control valves (21), (22), (23) and (25) are operated to the neutral stop position to move the hydraulic cylinders (7) and (1).
1), (12), and (13) are stopped, and a check means for checking and blocking the stop is provided, and a flow rate sensor (45) that detects the flow rate of the hydraulic oil from the pump (43) is provided, and Flow sensor (45)
If the detected value of is on the small flow rate side, the operating characteristics (F1), (F2), to the neutral stop position side of the control valves (21), (22), (23), and (25) by the speed reducing means, (F3)
If the detected value of the flow rate sensor (45) is on the high flow rate side, the operation characteristics (F1), (F2), and (F3) are changed on the low flow rate side as a whole. A backhoe equipped with a changing means for changing to.