JPH0629240Y2 - Boom type work implement work implement posture detection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a work implement posture detection device for a boom type work machine.

(Prior Art) A boom type work machine that is used by being mounted on a vehicle body such as a tractor,
For example, there is a front loader in which the attitude of the bucket pivotally attached to the tip of the boom is detected by a sensor, and the attitude of the bucket is controlled during the ascending / descending operation of the boom.

In this type of front loader, conventionally, the sensor is generally mounted in an exposed state on a boom mounting bracket or the like on the back surface of the bucket.

(Problems to be solved by the invention) In the past, the sensor was attached to the outside in an exposed state, so the sensor may be hit by obstacles, earth and sand during work, and the strength and other reliability are uncertain. There is a factor. Further, if the structure is such that the sensor is protected by a protective member in order to ensure reliability, a separate protective member is required, which is structurally complicated and causes a cost increase.

The present invention has been made in view of the above problems of the related art, and it is an object of the present invention to protect the sensor by using a part of the existing working machine to ensure the reliability of the sensor and prevent an increase in manufacturing cost. It is what

(Means for Solving Problems) As a means for solving the problems, the present invention connects a pair of left and right booms 13 which can be raised and lowered freely with a horizontal connecting pipe 18, and
A work tool 16 is rotatably provided at the tip of the boom 13,
In the boom type working machine equipped with the sensors 19 and 20 for detecting the posture of 16, the sensors 19 and 20 are stored in the connecting pipe 18,
A mounting plate 23 that supports the sensors 19 and 20 is provided below the mounting plate 23 so as to close the open end of the connecting pipe 18 leaving a cable extraction space 34, and the cable connected to the sensors 19 and 20. 41 is taken out from the cable taking-out space 34 to the outside of the connecting pipe 18, and this cable 34 is taken out from the mounting plate 23 and the boom 13
It is sandwiched between and fixed.

(Operation) Sensors 19 and 20 are connecting pipes 18 that connect the left and right booms 13
Since it is stored inside, it is protected by the connecting pipe 18.

When the work tool (bucket) 16 rotates during work, the rod
45, the horizontal shaft 22 rotates via the operation link 26, and the sensors 19, 2
0 works and detects the posture of the work implement 16.

The open end of the connecting pipe 18 is closed by the attachment plate 23, leaving the cable extraction space 34, to prevent intrusion of earth and sand or the like.

The cable 41 connected to the sensors 19 and 20 is extracted from the extraction space 34 to the outside of the connecting pipe 18, and then the mounting plate 23 and the boom are connected.
Fix it by sandwiching it with 13.

(Embodiment) The present invention will be described in detail below with reference to the illustrated embodiment.
In the figure, 1 is a tractor body, 2 is front wheels, 3 is rear wheels,
4 is a hood, 5 is a rear wheel fan, 6 is a driver's seat, and 7 is a steering wheel. A front loader 8 is a mast 10 which is detachably erected on both sides of the tractor vehicle body 1 via a mounting base 9, and a brace 11 which extends forward from the mast 10 and is detachably fixed to the front end portion of the tractor vehicle body 1. A boom 13 pivotally supported on the upper end of the mast 10 by a horizontal shaft 12 so as to be vertically rotatable,
Boom cylinder 14 for raising and lowering boom 13, boom
A bucket (working tool) 16 pivotally supported by a horizontal shaft 15 at the tip of 13 and a bucket cylinder 17 for rotating the bucket 16. The mast 10, the brace 11, the boom 13, the boom cylinder 14, and the bucket cylinder 17 are paired on the left and right, and the pair of left and right booms 13 are shown in FIGS.
As shown in the drawing, they are connected by a connecting pipe 18 in the lateral direction on the front side of the bonnet 4. In addition, connecting pipe
Reference numeral 18 penetrates the boom 13 in the lateral direction, and its outer end portion is slightly projected outward from the boom 13.

The connecting pipe 18 has a cylindrical shape with openings at both ends. Inside the connecting pipe 18, as shown in FIGS. 3 to 6, a first sensor 19 for detecting a ground inclination angle of the bucket 16 and a bucket.
Second sensor for detecting the relative tilt angle of the 16 to the boom 13
20 and are stored. The first sensor 19 uses a magnetic fluid, the second sensor 20 uses a potentiometer, and the first sensor 19 is attached to a U-shaped bracket 21. The bracket 21 is fixed to the inner end of the horizontal shaft 22, and the horizontal shaft 22 is rotatably supported by boss portions 24 and 25 fixed to a mounting plate 23, and the connecting pipe 1
The projecting end projecting outward from 8 has an operating link 26 so as to be close to the boom 13. On the side of the bracket 21 opposite to the horizontal axis 22, a horizontal axis 27 located on the same axis as the bracket is fixed. The second sensor 20 is attached to a U-shaped bracket 28, and its rotation shaft 29 is connected to the horizontal shaft 27. The horizontal shaft 27 is rotatably inserted into a boss portion 30 fixed to a U-shaped bracket 28, and the bracket 28 is a mounting plate.
It is fixed at 23. The mounting plate 23 has a substantially rectangular shape, and with the first and second sensors 19 and 20 stored in the connecting pipe 18, two bolts are attached to a pair of boss portions 31 welded to the outer surface of the boom 13. Installed by 32. The mounting plate 23 has notches 33 at the four corners, and among the notches 33 at the four corners, one notch 33a is formed larger than the other notches 33. The attachment plate 23 is attached so as to block the outside of the open end of the connection pipe 18 so that dirt and the like do not enter, and to form a cable extraction space 34 on the lower side. First and second
Lead wires 35 and 36 of the sensors 19 and 20 are connected to harnesses 39 and 40 of a sensor cable 41 via connectors 37 and 38, and the sensor cable 41 is covered with a corrugated tube for protection. The sensor cable 41 is provided in the connecting pipe 18 with a sufficient margin so as not to interfere with the rotation of the first sensor 19 in the connecting pipe 18 and the like. It is led out from the cable extraction space 34 to the outside of the connection pipe 18 via the lower side. The sensor cable 41 is clamped by the mounting plate 23 and the boom 13 between the connecting pipe 18 and the one boss portion 31, and is fixed with a slight pressing force.
It is fixed to the tractor body 1 side along a hydraulic pipe inside the boom 13 and the like.

The end of the operation link 26 is connected to a joint 46 at one end of a rod 45 via a pin 44, and the joint 47 at the other end of the rod 45 is connected to a bracket 49 on the back surface of the bucket 16 via a pin 48. The rod 45 constitutes a parallel link mechanism 100 together with a part of the boom 13, is arranged substantially parallel to the upper edge side of the boom 13 in a close state, and has the horizontal shafts 15, 22 and pins 46, 48.
Are arranged so as to form the four links of the parallel link mechanism 100. Therefore, if the bucket 17 rotates about the horizontal axis 15 due to the expansion and contraction of the bucket cylinder 17, the horizontal axis 22 rotates by the same angle. It is like this.

As shown in FIG. 7, the first sensor 19 has a magnetic fluid 51 enclosed in a bottomed cylindrical container 50 made of a non-magnetic material, and cylindrical permanent magnets 52 and 2 arranged around the outer periphery of the container 50. Coils
53 and 54 are fitted in, and when they are rotated around the horizontal axis 22, the distribution of the magnetic fluid 52 changes as shown in FIG.
The output voltage of 3,54 changes in proportion to the inclination angle to ground. A lid 55 is fitted on the container 50, and the first sensor 19 is housed in a case 56a.

The second sensor 20 rotates in proportion to the inclination angle of the bucket 16 with respect to the boom 13 when the horizontal shaft 22 rotates in conjunction with the bucket 16 and the rotary shaft 29 rotates via the bracket 21 and the horizontal shaft 27. The output voltage changes accordingly.

Reference numeral 56 is an operating device, and as shown in FIGS. 9 and 10, a case 57 mounted on the rear wheel fan 5 at one side of the driver's seat 6
In addition, the operation lever 5 that can be operated back and forth, left and right, and diagonally
8. First and second potentiometers 59, 60 and the like which are interlocked with the operating lever 58 are incorporated. That is, the operating lever 5
8 is pivotally supported by a movable frame 61 via a horizontal shaft 62.
Is supported on the case 57 side via the front-rear shaft 63, and therefore, the operation lever 58 has an arbitrary axis as shown in FIG. 10 and FIG. It can be operated in any direction. The operating lever 58 is elastically held in the neutral position by a spring (not shown).
The first potentiometer 59 is for instructing the raising and lowering of the boom 13, is interlocked with the back-and-forth movement of the operation lever 58 via the horizontal shaft 62, and outputs a command signal of a voltage corresponding to the operation amount of the operation lever 58. . The second potentiometer 60 is the bucket 16
For commanding the rotation of the control lever 58, and interlocking with the left-right movement of the operating lever 58 via the front-rear shaft 63 and the movable frame 61, and outputting a command signal of a voltage corresponding to the operation amount of the operating lever 58. A push button type automatic changeover switch 64 is attached to the upper end of the operation lever 58.

Reference numeral 71 is a stand for supporting the front loader 8 with the bottom surface of the bucket 16 grounded after removing the front loader 8 from the tractor body 1, and a connecting rod 72 for connecting the upper end portions of the mast 12 to each other. , Another supporting rod 73. Connecting rod 72
Is detachably attached to the bracket 49 of the bucket 16 with pins 74, and the supporting rod 73 is detachably attached to the middle of the connecting rod 72 and the boom 13 with pins 75 and 76.

FIG. 12 shows a hydraulic circuit of the lift cylinder 14 and the bucket cylinder 17. Reference numeral 77 is a first solenoid valve for controlling the lift cylinder 14, which has an ascending solenoid 78 and a descending solenoid 79. 80 is the second solenoid valve that controls the bucket cylinder 17,
It has a rake solenoid 82 and a dump solenoid 81.
The solenoid valves 77 and 80 are of the proportional type.

FIG. 13 shows a control circuit for driving and controlling the solenoid valves 77, 80.
In FIG. 13, reference numeral 83 denotes an ascending / descending discriminating circuit for discriminating the operating direction of the boom 13 depending on whether the voltage signal from the first potentiometer 59 is positive or negative. Ascending / descending when the operating lever 58 is positively operated. Discriminate the descent when the direction is negative. Reference numeral 84 is a first voltage-current conversion circuit for converting the voltage signal from the first potentiometer 59 into a current signal, which drives the ascending solenoid 78 or the descending solenoid 79 in the direction discriminated by the ascending / descending discrimination circuit 83. ing. Reference numeral 85 denotes a tilt storage circuit, which reads and stores the tilt signal from the first sensor 19 at the time when the automatic changeover switch 64 is turned on when the automatic changeover switch 64 is turned on and the operating lever 58 is operated in the upward direction. ing. A first deviation / amplification circuit 86 obtains and amplifies the deviation between the tilt signal from the first sensor 19 and the tilt storage signal from the tilt storage circuit 85. Reference numeral 87 is a target value setting circuit for setting a target value at the time of horizontal grounding in which the bottom surface of the bucket 16 is ground parallel to the ground. Reference numeral 88 denotes a second deviation / amplification circuit, which obtains and amplifies the deviation between the angle signal from the second sensor 20 and the target value from the setting circuit 87. 89 is an automatic manual switching circuit, which switches from manual to automatic when the automatic changeover switch 64 of the operating lever 58 is pressed to turn it on, and selects the first deviation / amplification circuit 86 by the rising signal from the rising / falling discrimination circuit 83. Then, the posture holding control is performed, and the second deviation / amplification circuit 88 is selected by the descending signal to perform the horizontal grounding control. 90 is a scoop / dump discriminating circuit that discriminates the operating direction of the bucket 16 by the positive / negative of the voltage signal sent from the second potentiometer 60, the first deviation / amplification circuit 86 or the second deviation / amplification circuit 88 via the switching circuit 89. When the signal from the switching circuit 89 is positive, the scooping is performed, and when the signal is negative, the dump is discriminated. Reference numeral 91 is a second voltage-current conversion circuit for converting the voltage signal from the switching circuit 89 into a current signal, which drives the rake solenoid 82 or the dump solenoid 81 in the direction discriminated by the rake / dump discrimination circuit 90. There is.

In the above configuration, when the operation lever 58 is operated in the upward or downward direction during manual control, the first potentiometer 59
Positive or negative voltage signal is output from the up / down discrimination circuit
The first voltage-current conversion circuit 84 converts the voltage signal into a current signal, and the first solenoid valve 77.
The ascending solenoid 78 or the descending solenoid 79 is driven.
At this time, since the first solenoid valve 77 is of the proportional type, it is switched to ascend or descend in proportion to the absolute value of the voltage signal, and the boom 13 ascends or descends at a speed proportional to the operation amount of the operation lever 58.

When the operating lever 58 is operated in the scooping or dumping direction, the positive or negative voltage signal from the second potentiometer 60 causes the second electromagnetic wave via the scooping / dumping discrimination circuit 90 and the second voltage-current conversion circuit 91. The valve 80 switches to the scoop or dump direction and the bucket 16 scoops or dumps in the same manner as described above.

When scooping earth and sand into the bucket 16, the bucket 16 is grounded horizontally on the bottom surface, and then the operation lever 58 is slightly rotated in the scooping direction to be in the state of the phantom line in FIG. At this time, since the bucket 16 rotates about the horizontal shaft 15 in the direction indicated by the arrow a, the operating link 26 rotates about the horizontal shaft 22 via the rod 45 as indicated by b in FIG.
The first sensor 19 turns in the tilted state as shown in FIG. 8 by rotating in the direction of the arrow, and outputs a negative voltage signal according to the ground tilt angle of the bucket 16.

Therefore, when the automatic changeover switch 64 of the operation lever 58 is pushed and operated in the ascending direction, the boom 13 ascends while the bucket 16 maintains the posture of the phantom line in FIG. 1, and spillage of earth and sand from the bucket 16 is prevented. . That is, the automatic changeover switch 64
When is pressed, the switching circuit 89 switches to the automatic side, and the tilt storage circuit 85 stores the tilt signal from the first sensor 19, that is, the tilted posture of the bucket 16 at the start of rising. Also, since the operating lever 58 is operated in the upward direction,
The descending discrimination circuit 83 discriminates the rising, and the switching circuit 89 selects the first deviation / amplification circuit 86 side. Then, when the boom 16 starts to rise, if the bucket 16 remains in the fixed state, the first
Since the sensor 19 further tilts and its tilt signal becomes large on the negative side, the first deviation / amplification circuit 86 obtains the deviation between the tilt signal from the first sensor 19 and the tilt memory signal from the tilt memory circuit 85. To amplify. Since the deviation signal at this time is negative, the scoop / dump discriminating circuit 90 discriminates the dump, and the dump solenoid of the second solenoid valve 80 is passed through the second voltage / current converting circuit 91.
By driving 81, the bucket 16 rotates in the dump direction. When the bucket 16 rotates in the dump direction, the operation link 26 rotates about the horizontal shaft 22 in the direction opposite to the arrow b direction via the rod 45, and
Since the sensor 19 returns to the state shown in FIG. 8, the dumping operation of the bucket 16 is stopped when the tilt signal from the first sensor 19 matches the tilt storage signal of the tilt storage circuit 85. In the same way, the boom 13
Rises.

After dumping the bucket 16 at the raised position of the boom 13 to discharge the earth and sand, when lowering the boom 13, push the automatic changeover switch 64 and operate the operating lever 58 in the lowering direction to make the bottom surface of the bucket 16 horizontal. Ground to. That is, when the operation lever 58 is operated in the descending direction, the up / down discriminating circuit 83
Discriminates the fall, the switching circuit 89 selects the second deviation / amplification circuit 88 side. Then, if the bucket 13 is in the dumping state, the second state is passed through the rod 45, the operation link 26, the horizontal shaft 22, etc.
The sensor 20 detects the inclination angle of the bucket 16 with respect to the boom 13, and the deviation between the inclination signal at that time and the target value of the setting circuit 87 is obtained by the second deviation and the amplification circuit 88. Since the deviation signal in this case is positive, the rake / dump discrimination circuit 90 discriminates the rake, drives the rake solenoid 82 of the second solenoid valve 80 via the second voltage / current conversion circuit 91, and the bucket 16 Rotate to the rake side. When the bucket 16 rotates in the scooping direction, the operating link 26 rotates around the horizontal shaft 22 in the direction of the arrow b via the rod 45, and the inclination signal of the second sensor 20 approaches the target value. Then, when the tilt signal from the second sensor 20 matches the target value, the tilt angle of the bucket 16 with respect to the boom 13 becomes an angle at which the bottom surface of the bucket 16 horizontally touches the ground at the lowered position of the boom 13, and the bucket 16 moves. Stop the rake action. Therefore, the bucket 16 can be grounded horizontally on the bottom surface simply by lowering the boom 13.

In the embodiment, the bucket 16 is exemplified as the work tool, but a fork or the like may be used, and the front loader 8 may be used.
The present invention is not limited to the above and can be similarly performed in a backhoe.

If the lower edge of the mounting plate 23 is straightened as shown by the solid line in FIG. 3, the cable take-out space 34 becomes wider, and the state of the sensor cable 41 in the connecting pipe 18 can be confirmed from this take-out space 34. However, even if earth and sand enter the connecting pipe 18, it will not be discharged to the outside from the extraction space 34 due to vibration and the like, but earth and sand will not accumulate in the connecting pipe 18, but it is not limited to this. For example, as shown by the phantom line in FIG. 3, the vertical width of the mounting plate 23 may be made larger than that of the connecting pipe 18, and a cutout may be provided at the lower end edge side for the cable extraction space 34.

In Fig. 12, the boom cylinder 14 and the bucket cylinder are
Although the hydraulic circuit in which 17 and 17 are connected in parallel has been exemplified, a hydraulic circuit in which they are connected in series as shown in FIG. 14 can be similarly implemented.

According to the present invention, a connecting pipe that connects the left and right booms 13
Since the sensors 19 and 20 are housed inside the sensor 18, the sensors 19 and 20 can be reliably protected from obstacles and reliability is improved. Further, since the connecting pipe 18 is used, a protective member is not required separately, and it is possible to prevent an increase in manufacturing cost. Furthermore, the open end of the connecting pipe 18 leaves the cable extraction space 34, and the sensor
Since it is blocked by the mounting plate 23 that supports 19, 20, it is possible to reduce or prevent the intrusion of earth and sand into the connecting pipe 18. Further, since the cable 41 taken out from the cable taking-out space 34 to the outside of the connecting pipe 18 is fixed by being sandwiched between the mounting plate 23 and the boom 13, a fixture dedicated to the cable 41 is not necessary.

[Brief description of drawings]

The drawings show an embodiment of the present invention. FIG. 1 is a side view of the whole, and FIG. 2 is a perspective view of a front portion of a front loader.
3 is a side view of the sensor mounting portion, and FIG. 4 is A- in FIG.
FIG. 5 is a sectional view of the sensor mounting portion, FIG. 7 is a sectional view of the first sensor, and FIG. 8 is the same operation explanation. Fig. 9, Fig. 9 is a cross-sectional rear view of the operating device, Fig. 10 is a view taken along the line CC in Fig. 9, Fig. 11 is an explanatory diagram of the operating position, Fig. 12 is a hydraulic circuit diagram, and Fig. 13 is The control circuit diagram, FIG. 14 is a hydraulic circuit diagram. 1 ... tractor body, 8 ... front loader, 13 ... boom,
16 ... Bucket, 18 ... Connection pipe, 19 ... First sensor, 20 ...
2nd sensor, 22 ... Horizontal axis, 23 ... Mounting plate, 26 ... Operating link,
34… Cable exit space, 41… Sensor cable, 45… Rod.

Claims (1)

[Scope of utility model registration request] 1. A sensor 19 for detecting a posture of a working tool 16 by connecting a pair of left and right booms 13 which can be raised and lowered freely with a lateral connecting pipe 18 and a working tool 16 rotatably provided at a tip end portion of the boom 13. In a boom type working machine provided with the sensors 20 and 20, the sensors 19 and 20 are housed in the connecting pipe 18, and a mounting plate 23 that supports the sensors 19 and 20 is provided below the mounting plate 23.
It is provided so as to close the open end of the connection pipe 18 leaving 34, and the cable 41 connected to the sensors 19 and 20 is taken out from the cable extraction space 34 to the outside of the connection pipe 18, and this cable 34 is attached to the mounting plate 23. A work implement posture detection device for a boom type work machine, which is sandwiched and fixed between a boom 13 and the boom 13.