JPH0881979A - Backhoe - Google Patents

Abstract

PURPOSE: To decelerate a hydraulic cylinder for driving a backhoe device accurately before the hydraulic cylinder reaches a stroke end and the backhoe device is stopped in a backhoe constituted so that the backhoe device is stopped when a restraint surface is set in an external space by a set distance from a parting section covering an operating section and a bucket trys to cross the restraint surface and intrude to the parting section side and a contact between the bucket and the parting section is avoided. CONSTITUTION: A cushioning mechanism, in which the oil path of a hydraulic fluid is throttled by their own expansion-contraction operation of hydraulic cylinders 7, 11-13 and the speed of expansion and contraction of the hyraulic cylinders 7, 11-13 is decelerated when the hydraulic cylinders are expanded and contracted near stroke ends, is provided. When the hydraulic cylinders 7, 11-13 reach near stroke ends, solenoid valves for the hydraulic cylinders 7, 11-13 are operated to the neutral stop place sides apart from a cushioning mechanism on the basis of the detection of position sensors 36-39. The speed of the expansion and contraction of the hydraulic cylinders 7, 11-13 is decelerated by the throttling operation of the supply and discharge of the hydraulic fluid to and from the hydraulic cylinders 7, 11-13.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure for controlling the operation of a hydraulic cylinder for driving a backhoe device in a backhoe.

[0002]

2. Description of the Related Art In a backhoe, for example, Japanese Patent Laid-Open No.
As disclosed in Japanese Patent Publication No. 296212, when the hydraulic cylinder for driving the backhoe device expands and contracts to the vicinity of its stroke end, the hydraulic cylinder itself (piston rod) expands and contracts so that an oil passage for hydraulic oil to the hydraulic cylinder is formed. Some are equipped with a cushion mechanism that is operated to reduce the expansion and contraction speed of a hydraulic cylinder by being throttled. As a result, even if the operator extends and retracts the hydraulic cylinder for driving the backhoe device to the stroke end, the hydraulic cylinder is decelerated by the cushion mechanism before the stroke end, and the hydraulic cylinder stops smoothly at the stroke end. .

[0003]

Since the above-mentioned cushion mechanism is constructed so as to squeeze the oil passage of the hydraulic oil by the expansion and contraction operation of the hydraulic cylinder itself, the degree of squeezing of the oil passage is constant. As a result, when the temperature of the hydraulic oil or the load applied to the hydraulic cylinder changes, the throttling characteristic of the hydraulic oil by this cushion mechanism also changes.
The deceleration operation of the hydraulic cylinder before the stroke end may be insufficient and the hydraulic cylinder may not be able to smoothly stop at the stroke end. It is an object of the present invention to configure a backhoe such that a hydraulic cylinder for driving the backhoe device is appropriately decelerated before the stroke end regardless of changes in various conditions and is smoothly stopped at the stroke end.

[0004]

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 manually operated, a solenoid valve that supplies and discharges hydraulic oil to and from a hydraulic cylinder for driving the backhoe device, and a control device that switches and operates the solenoid valve based on the operation of the manual operation tool. A setting means for setting a check surface in a space that is outwardly separated by a predetermined distance from an external frame that is provided and covers the operating part provided on the swivel base, a position sensor that detects the position of the bucket of the backhoe device, and a position sensor. When the bucket tries to enter the operation section side beyond the restraint surface based on the detection of the check, the check valve is provided with a check unit that operates the solenoid valve to the neutral stop position to stop the hydraulic cylinder and prevent the check. When it expands and contracts near the stroke end, the hydraulic cylinder itself expands and contracts, and the hydraulic oil passage to the hydraulic cylinder is throttled.
Equipped with a cushion mechanism for decelerating the expansion and contraction speed of the hydraulic cylinder.When the hydraulic cylinder expands and contracts near the stroke end, the solenoid valve is operated to the neutral stop position side based on the detection of the position sensor, and the hydraulic oil to the hydraulic cylinder There is provided deceleration control means for decelerating the expansion and contraction speed of the hydraulic cylinder by squeezing the supply and discharge of the hydraulic cylinder.

[0005]

In the backhoe, as shown in FIG. 1 and FIG. 4, for example, a hydraulic cylinder 7 for driving the backhoe device 3,
11, 12, 13 is configured to supply and discharge hydraulic oil via an electromagnetic valve, and the hydraulic cylinders 7, 11, 12, 13 are configured to be expanded and contracted by the electromagnetic valve. is there. In the above-mentioned backhoe, the restraint surfaces A1 and A2, which are separated from the outer frames 29 and 30 that cover the driving unit 27 provided on the swivel base 2 by a predetermined distance outwardly, are set in the space, and the bucket 6 of the backhoe device 3 is set. A position sensor for detecting the position is provided, and when the bucket 6 tries to enter the operation unit 27 side beyond the check surfaces A1 and A2 based on the detection of the position sensor, the solenoid valve is operated to the neutral stop position and the hydraulic cylinders 7 and 11 are operated. , 12, 13 are configured to be automatically stopped. As a result, even if the operator of the operation unit 27 mistakenly operates the backhoe device 3,
Contact between the bucket 6 and the external frames 29, 30 is prevented in advance.

In the backhoe as described above, if the position of the bucket 6 is detected by the position sensor, the boom 4
If the angle of the boom 4, the arm 5, etc. is known, the expansion / contraction position of the hydraulic cylinders 7, 11, 12, 13 for driving the backhoe device 3 is known. When the operation current to the solenoid valve is controlled to change the opening degree of the solenoid valve, the solenoid valve can be operated to change the hydraulic cylinders 7, 1
It is possible to control the flow rate of the hydraulic oil supplied to and discharged from 1, 12, and 13 to be large or small.

According to this structure, when the hydraulic cylinder reaches the vicinity of the stroke end and the cushion mechanism starts to operate, the solenoid valve for the hydraulic Linder is operated to the neutral stop position side based on the detection of the position sensor. Begin to be. As a result, as the hydraulic cylinder approaches the stroke end, the hydraulic fluid discharged from the hydraulic cylinder is throttled by the cushion mechanism and the solenoid valve, and the expansion / contraction speed of the hydraulic cylinder is decelerated.

In this case, the throttle characteristic of the hydraulic fluid by the cushion mechanism is constant unless the temperature of the hydraulic fluid changes, whereas the throttle characteristic of the hydraulic fluid by the solenoid valve is easy by controlling the operating current. Can be changed to. Therefore,
If the cushioning mechanism changes the throttle characteristic of the hydraulic fluid due to changes in the temperature of the hydraulic fluid and the deceleration operation of the hydraulic cylinder before the stroke end becomes insufficient, change the throttle characteristic of the hydraulic oil by the solenoid valve. By performing the changing operation, the throttle characteristic of the hydraulic oil when both the cushion mechanism and the solenoid valve are combined can be set to an appropriate one.

[0009]

As described above, by using the solenoid valve for the hydraulic cylinder for the throttle in addition to the existing cushion mechanism, the hydraulic pressure before the stroke end is irrespective of the change in the temperature of the hydraulic oil. The deceleration operation of the cylinder can be performed accurately, and it is possible to prevent the condition that the hydraulic cylinder cannot be stopped smoothly at the stroke end due to insufficient deceleration operation and improve the workability of the backhoe. I was able to. In this case, the existing configuration (position sensor, control valve, and the like) for avoiding contact between the outer frame of the operating unit and the bucket is effectively used, which is also advantageous in terms of simplification of the structure.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. (1) FIG. 4 shows the entire side surface of a backhoe, in which a dozer 20 and a swivel base 2 are supported on a traveling device 1 of a rubber crawler type, 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. 4, the boom 4 of the backhoe device 3 includes a first boom portion 4a connected to a swivel base 2 so as to be vertically swingable, and left and right 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 (corresponding to a solenoid valve), 32 (corresponding to a solenoid valve), 33 (corresponding to a solenoid valve) for each control valve 21 to 25, which generates a pilot pressure for operating the opening degree. ), 34, 35 (corresponding to solenoid valves).

As shown in FIGS. 7 and 3, the swivel base 2 has a right operation lever 9 (corresponding to an artificial operation tool) and a left operation lever 1 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 structure, when the right operating lever 9 is operated forward or backward, the control device 19 operates the pilot valve 31 based on this, and the control valve 21 is operated to the lower side or the upper side of the first boom portion 4a. When operated to the right or left, the control device 19 controls the pilot valve 3 based on this.
3 is operated, and the control valve 23 is operated to the soil discharge side or the scraping side of the bucket 6. When the left operation lever 10 is operated forward or backward, the pilot valve 32 is operated by the control device 19 based on this, the control valve 22 is operated to the raising side or the scraping side of the arm 5, and when it is operated to the right or left, the pilot valve 32 is operated. Based on this, the control device 19 operates the pilot valve 34 to operate the control valve 24 to the right turning side or the left turning side. When the operation pedal 26 is stepped to the right or left, the control device 19 operates the pilot valve 35 based on this, and the control valve 25 is operated to the right or left swing side of the second boom portion 4b.

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 expand and contract and 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 portion 27 of the swivel base 2 will be described. As shown in FIG. 2 and FIG. 3, 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 2, 3,
As shown in FIG. 4, a partition wall 29 (corresponding to an external frame) with a window for partitioning the backhoe device 3 and the operation unit 27 is provided at the left and right center of the swivel base 2, and the swivel base 2 is provided at the upper end of the partition wall 29. A semi-circular roof portion 30 (corresponding to an external frame) along the outer side of is fixed.

As shown in FIGS. 4 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. 1, 2 and 3, 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 side of the front side by a predetermined distance is set in the space (corresponding to the setting means), Front second with a predetermined vertical width separated by a predetermined distance
The restraint surface A2 (corresponding to the restraint surface) is set in the space in series with the front first restraint surface A1 (corresponding to a setting unit). In the range above the predetermined position D, a surface is set apart from the front first and second check surfaces A1 and A2 by a predetermined distance, and the surface of this space and the front first and second check surfaces are set. A1, A
2 is the front first check area B1 and the second front check area B
It is set as 2.

As shown in FIGS. 3 and 2, a planar shape extending from the end portion of the front first check surface A1 on the backhoe device 3 side to the rear side and separated by a predetermined distance from the partition wall 29 to the right side of the drawing in FIG. The horizontal restraint surface A3 (corresponding to the restraint surface) is set in the space (corresponding to the setting means). A plane separated from the lateral restraint surface A3 by a predetermined distance to the right side of the paper surface of FIG. 3 is set, and a space between this plane and the lateral restraint surface A3 is set as a lateral restraint area B3. The front first and second check surfaces A as described above
1, A2, front first and second front restraint areas B1, B2, lateral restraint surface A3, and horizontal restraint area B3 are set with respect to the space of the swivel base 2, and the swivel base 2 swivels. Along with, it moves with the swivel base 2.

(3) Next, the predetermined position D in FIGS. 1 and 2 will be described. As shown in FIG. 1, 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 operating 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,
Control device 19 controls pilot valves 31, 32, 33, 3
5 is operated, and the expansion / contraction speed of the hydraulic cylinders 7, 11, 12, 13 is decelerated by the control valves 21, 22, 23, 25. In this case, the closer the front end of the bucket 6 is to the front first and front second check surfaces A1 and A2 in the front first and second check areas B1 and B2, the more the hydraulic cylinders 7 and 1 are moved.
The expansion and contraction speeds of 1, 12, and 13 are greatly decelerated.

On the contrary, the front first and second front restraint regions B1 and B2
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, the hydraulic cylinders 7, The expansion / contraction speeds of 11, 12, and 13 are increased, and when returning from the front first and second front restraint regions B1 and B2, the original expansion and contraction speeds are restored.

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 over the front first or second check surfaces A1 and A2 such as the operation of the arm 5 on the scraping side, the control device 19 causes the pilot valve 3 to operate.
1, 32, 33, 35 are operated to the neutral stop position, the pilot pressure disappears, the control valves 21, 22, 23, 25 are operated to the neutral stop position, and the hydraulic cylinders 7, 11, 12, 1
3 is stopped (corresponding 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
2 and 3, the front end of the 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), the 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.

(5) Next, as shown in FIG. 1, the bucket 6
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. 1 and 2 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. 2 and 3, 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 side surface of the second side enters the lateral restraint region B3, the control device 19 operates the pilot valve 35 to decelerate the expansion / contraction speed of the hydraulic cylinder 7 of the second boom portion 4b 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.

On the contrary, the left lateral surface of the bucket 6 is the lateral restraint surface A.
When the second boom portion 4b is operated in a direction away from 3, the expansion / contraction speed of the hydraulic cylinder 7 of the second boom portion 4b is increased in the lateral restraint region B3, contrary to the deceleration operation described above. Go and return to the original expansion / contraction speed when exiting from the lateral restraint area B3. Then, when the left lateral side surface of the bucket 6 reaches the lateral restraint surface A3 and is about to be operated toward the operation unit 27 side beyond the lateral restraint surface A3, the control device 1
The pilot valve 35 is operated to the neutral stop position by 9 and the pilot pressure disappears, and the control valve 25 stops the hydraulic cylinder 7 of the second boom portion 4b.

(7) Next, the cushion mechanism 42 mounted on the hydraulic cylinders 7, 11, 12, 13 for driving the backhoe device 3 will be described. As shown in FIG. 5, one oil chamber 7a in the hydraulic cylinder 7 and the oil passage 43 on the control valve 25 side are connected via an oil passage hole 44, and are connected to the end of the piston 7b of the hydraulic cylinder 7. A pin 7c for entering the oil passage hole 44 is provided. The oil passage 43 and the oil chamber 7a are connected via the throttle valve 45 and the oil passage 46, and the oil passage 43 and the oil chamber 7a are connected via the check valve 47 and the oil passage 48, so that the cushion mechanism 42 is connected. Is configured. The cushion mechanism 42 described above is provided at the opposite end of the hydraulic cylinder 7 and at both ends of the hydraulic cylinders 11, 12, 13.

With the above structure, for example, the other oil chamber 7d
When hydraulic oil is supplied to the piston 7b and the piston 7b moves to the right in the drawing, the hydraulic oil in the oil chamber 7a is initially discharged to the oil passage 43 through the oil passage hole 44. When the piston 7b expands and contracts to the vicinity of the stroke end, the pin 7c of the piston 7b enters the oil passage hole 44 and the oil passage hole 44 is substantially closed, so that the working oil in the oil chamber 7a flows into the oil passage 46 and the throttle. Valve 4
The oil is discharged to the oil passage 43 through 5, and the piston 7b is decelerated. On the contrary, the pin 7c of the piston 7b is connected to the oil passage hole 44.
When the piston 7b is moved to the left side of the drawing in the entered state, the operating oil supplied from the control valve 25 to the oil passage 43 is supplied to the oil chamber 7a via the check valve 47 and the oil passage 48. Then, the piston 7b moves to the left side of the drawing.

(8) Next, the hydraulic cylinders 7, 11, 1
A case in which 2 and 13 expand and contract to reach the stroke end will be described. When only the cushion mechanism 42 shown in FIG. 5 is operated, when the hydraulic cylinders 7, 11, 12, 13 reach the stroke end, the hydraulic cylinders 7, 11, 1
The flow rate of the hydraulic fluid discharged from the hydraulic fluids 2, 13 through the cushion mechanism 42 is as shown by the solid line E1 in FIG. 6, and the characteristic of the solid line E1 is constant unless the temperature of the hydraulic fluid changes. Is.

Since the vertical angle and the like of the first boom portion 4a shown in FIG. 4 and the expanded and contracted positions of the hydraulic cylinders 7, 11, 12, 13 correspond to each other, the potentiometers 36 to 39 shown in FIG. If the vertical angle of the portion 4a is detected, the hydraulic cylinders 7, 11, 12,
The expansion / contraction position of 13 can also be detected.

As a result, for example, when the hydraulic cylinder 7 of the second boom portion 4b reaches the vicinity of the stroke end as shown in FIG. 5 and the pin 7c of the piston 7b begins to enter the oil passage hole 44, the potentiometer 37 causes the hydraulic cylinder 7 to move. It is detected that 7 has reached near the stroke end. As a result, the control device 19 starts to operate the pilot valve 35 toward the neutral stop position side, and the control valve 25 also starts to operate toward the neutral stop position side. As the hydraulic cylinder 7 approaches the stroke end, the hydraulic cylinder The hydraulic oil discharged from the oil chamber 7a of No. 7 is throttled by the cushion mechanism 42 and then by the control valve 25, and the expansion / contraction speed of the hydraulic cylinder 7 is decelerated (the above corresponds to the deceleration control means).

As shown in FIG. 7, an adjusting dial 49 is provided in the driving section 27, the operating position of the adjusting dial 49 is input to the control device 19, and the operator can adjust the adjusting dial 4
9 is operated, the pilot valve 35 when the hydraulic cylinder 7 reaches the stroke end as described above.
The control valve 25 is configured so that the degree of operation of the control valve 25 toward the closing side can be changed. As a result, by operating the adjustment dial 49, the characteristics of the deceleration operation when the hydraulic cylinder 7 reaches the stroke end can be changed, as shown by the chain lines E2 and E3 in FIG. The above adjustment operation is
The same applies to the other hydraulic cylinders 11, 12, and 13.

[Other Embodiment] In the above embodiment, the bucket 6 is used.
The front first and second front restraint surfaces A1 and A2 and the horizontal restraint surface A3 are set on the basis of 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.

Although the pilot valves 31 to 35 of the electromagnetic proportional pressure reducing valve type are electromagnetic valves in the above-described embodiment, the pilot valves 31 to 35 are abolished and the control valves 21 to 25 are constituted by the electromagnetic proportional pressure reducing valve type. The control valves 21 to 25 may be electromagnetic valves. In this case the right and left operating levers 9,
10, the operation position of the operation pedal 26, the potentiometer 1
5 to 18 electrically detect, and based on the detected value, the control valve 21 to 25 (corresponding to the solenoid valve) of the electromagnetic proportional pressure reducing valve type directly operates.

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

FIG. 2 is a schematic front view of a backhoe showing front first check surfaces and front second check surfaces, front first and second check areas, lateral check surfaces, and horizontal check areas.

FIG. 3 is a schematic plan view of a backhoe showing front first and front first restraint areas, lateral restraint surfaces, and lateral restraint areas.

FIG. 4 is an overall side view of the backhoe.

FIG. 5 is a sectional view showing a cushion mechanism provided at an end of a hydraulic cylinder.

FIG. 6 is a diagram showing the relationship between the flow rate of hydraulic oil in a hydraulic cylinder and the degree of throttling (deceleration operation).

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 Revolving base 3 Backhoe device 6 Bucket 7, 11, 12, 13 Hydraulic cylinder 9, 10, 26 Human operating tool 19 Control device 27 Operating part 29, 30 External frame 31, 32, 33, 35 Solenoid valve 36, 37, 38 , 39 Position sensor 42 Cushion mechanism 43 Oil passage A1, A2, A3 Check surface

Claims (1)

[Claims] 1. An artificial operation tool (9) which is artificially operated,
(10), (26) and solenoid valves (31), (32) for supplying / discharging hydraulic oil to / from the hydraulic cylinders (7), (11), (12), (13) for driving the backhoe device (3). ), (3
3) and (35), and the artificial operation tools (9), (10),
Based on the operation of (26), the solenoid valves (31), (3
2), (33), (35) control device for switching operation (1
9), and the check surfaces (A1), (A2) which are outwardly separated by a predetermined distance from the external frames (29), (30) that cover the operating part (27) provided on the swivel base (2). , (A3) in space, and position sensors (36), (3) for detecting the position of the bucket (6) of the backhoe device (3).
7), (38), (39) and the position sensor (3
6), (37), (38), and (39), the bucket (6) detects the check surfaces (A1), (A2),
If an attempt is made to enter the operation unit (27) side beyond (A3), the solenoid valves (31), (32), (33),
The hydraulic cylinder (7) is provided with: , (11), (12), (1
When 3) expands and contracts to near the stroke end, the hydraulic cylinders (7), (11), (12), (13).
The hydraulic cylinders (7), (1
The hydraulic oil passage (43) to 1), (12), (13) is throttled, and the hydraulic cylinders (7), (11),
The hydraulic cylinders (7), (11), (12), (1) are provided with a cushion mechanism (42) for decelerating the expansion and contraction speed of (12), (13).
When 3) expands and contracts to near the stroke end, the position sensors (36), (37), (38), (3
9) based on the detection of the solenoid valve (31), (32),
(33) and (35) are operated to the neutral stop position side, and the supply and discharge of hydraulic oil to and from the hydraulic cylinders (7), (11), (12), and (13) are throttled to operate the hydraulic cylinder. A backhoe provided with deceleration control means for decelerating the expansion / contraction speeds of (7), (11), (12), and (13).