JPH0634431Y2 - Boom type work implement attitude detector - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a work implement posture detector 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, in a front loader or the like, a boom is rotatably supported on a vehicle body side by a horizontal shaft, and a bucket (work implement) is rotatably supported by a horizontal shaft on a tip end portion of the boom, so that the boom is midway. There is one in which a bucket cylinder is provided so as to connect the bracket protruding upward and the bucket, and the angle of the bucket is adjusted by expanding and contracting the bucket cylinder. There is provided a first sensor for detecting an angle and a second sensor for detecting an inclination angle of a bucket with respect to a boom, and a posture of the bucket is controlled by a signal from these sensors during work.

However, in the conventional working machine of this type, it is general that the first sensor is attached to a column for mounting the boom on the vehicle body, and the second sensor is attached to a bracket or the like on the back surface of the bucket (for example, Japanese Patent Application No. 30222). .

(Problems to be solved by the invention) Conventionally, since the sensor was mounted on the outside in an exposed state, obstacles, earth and sand, etc. may hit the sensor during work, causing damage to strength and reliability. was there. Further, in order to improve the control performance, it is necessary that the resolution of the sensor is high. However, if the cylinder stroke is directly detected in order to improve the resolution, a very expensive sensor is required at present. there were.

In view of the above problems, the present invention is intended to enhance the strength and other reliability of the sensor and to make it possible to exhibit sufficient control performance even with an inexpensive sensor.

(Means for Solving the Problems) The technical means of the present invention for solving this technical problem is that the boom 13 is rotatably supported by the horizontal shaft 12 on the vehicle body 1 side and the boom 13 is A work tool 16 is rotatably supported by a horizontal shaft 15 at the tip of the bracket, a bracket 101 is projected upward in the middle of the boom 13, and the bracket 101 and the work tool 16 are connected to the upper side of the boom 13. As described above, a work tool cylinder 17 for adjusting the angle of the work tool 16 is provided, and a first sensor 19 for detecting a ground inclination angle of the work tool 16 and a boom 13 are provided.
Sensor for detecting the inclination angle of the work implement 16 with respect to the
20 and a boom type working machine in which the posture of the work implement 16 is controlled by signals from the first and second sensors 19 and 20, a sensor case 18 is provided on the rear side of the bracket 101 on the boom 13. Is provided, the first and second sensors 19, 20 are stored in the sensor case 18, the first and second sensors 19, 20 are interlocked with the horizontal shaft 22, and the horizontal shaft 22 is an operating link. 2
It is at the point of interlocking connection with the work implement 16 via 6.

(Operation) Since the first and second sensors 19 and 20 are housed in the sensor case 18, they are protected by the sensor case 18.

When the work implement (bucket) 16 rotates about the horizontal shaft 15 during work, the first and second sensors 19 and 20 act via the rod 45, the operation link 26, and the horizontal shaft 22. Then, the first sensor 19 detects the inclination angle of the work implement (bucket) 16 to the ground, and the second sensor
Reference numeral 20 detects a relative inclination angle of the work implement (bucket) 16 with respect to the boom 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 that is detachably erected on both sides of the tractor body 1, a brace 11 that extends forward from the mast 10 and is detachably fixed to the front end of the tractor body 1, and an upper end portion of the mast 10. A boom 13 pivotally supported by a horizontal shaft 12 for vertical movement, a boom cylinder 14 for raising and lowering the boom 13, and a horizontal shaft at the tip of the boom 13.
Bucket (work implement) 16, which is rotatably supported by 15,
It is composed of 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.

A bracket 101 is provided so as to project upward in the middle of the boom 13.
A connecting plate 103 pivotally mounted around a horizontal shaft 102 is provided in the middle of the front side of the boom 13, and the upper end of the connecting plate 103 and the upper rear end of the bucket 16 are connected by a connecting rod 104. Further, the bucket cylinder 17 is connected between the bracket 101 and the upper rear end of the connecting plate 103, whereby the front end of the bucket cylinder 17 is connected to the bucket 16 via the connecting plate 103 and the connecting rod 104, and the bucket cylinder 17 The angle of the bucket 16 can be adjusted around the horizontal axis 15 by expanding and contracting.

18 is a sensor case provided in the middle of the boom 13,
It is arranged on the upper side of 13 and on the rear side of the bracket 101,
Boom 13 or bracket 10 by welding or bolts
Sticked to 1. As shown in FIGS. 2 to 4, the sensor case 18 has a bottomed cylindrical shape with one end opening, and the sensor case 18 has a first sensor 19 for detecting the inclination angle of the bucket 16 with respect to the ground, and a bucket. The second sensor 20 for detecting the relative inclination angle of the 16 with respect to the boom 13 is stored. The first sensor 19 uses a magnetic fluid, and the second sensor
The sensor 20 uses a potentiometer,
The first sensor 19 is attached to a U-shaped bracket 21. The bracket 21 is fixed to the inner end of the horizontal axis 22
22 is rotatably supported by boss portions 24, 25 fixed to a cover plate 23, and has an operating link 26 at its outer end. 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 bracket 28 having a U-shape, and its rotation axis 29 is a horizontal axis.
It is connected to 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 fixed to a cover plate 23. The lid plate 23 has a disk shape, and is attached by a bolt nut 32 to a pair of attachment pieces 31 projecting from the sensor case 18 with the first and second sensors 19 and 20 stored in the sensor case 18. ing. Lid plate
Reference numeral 23 has a notch 33 for taking out the tube, and closes the outer end opening of the sensor case 18 on the outer side so as to prevent dirt and the like from entering. The lead wires of the first and second sensors 19, 20 are connected to harnesses 39, 40 via connectors 37, 38, and the harnesses 39, 40 are covered with a corrugated tube 41 for protection. The corrugated tube 41 is provided in the sensor case 18 with a sufficient margin so that the corrugated tube 41 does not interfere with the rotation of the first sensor 19 or the like in the sensor case 18. Cutout for tube extraction through the lower side 33
Is led to the outside of the sensor case 18. The corrugated tube 41 is guided to the tractor vehicle body 1 side along a hydraulic pipe inside the boom 13.

The tip of the operating link 26 is connected to one end of a rod 45 via a pin 44, and the other end of the rod 45 is connected to a connecting plate via a pin 48.
It is connected to the middle part of 103. The rod 45 is arranged substantially parallel to the upper edge side of the boom 13 in a close state, and the horizontal axes 15 and 2
2, the pins 44, 48 are arranged so as to form the four joints of the parallel link mechanism. Therefore, if the bucket 16 is rotated about the horizontal axis 15 due to the expansion and contraction of the bucket cylinder 17, the pins 16 and 48 are moved horizontally. The shaft 22 is adapted to rotate.

As shown in FIG. 5, in the first sensor 19, a magnetic fluid 51 is enclosed in a bottomed cylindrical container 50 made of a non-magnetic material, and cylindrical permanent magnets 52 and 2 are provided on 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 56.

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 107 denotes an indicator provided on the operating link 26. The standing portion 108 protrudes upward from the upper end of the operating link 26, and L stands from the upper end of the standing portion 108.
The display unit 109 is bent forward in a letter shape. The display 107 is rotated about the horizontal axis 22 in association with the rotation of the bucket 16, and the inclination of the display unit 109 is always matched with the inclination angle of the bottom surface of the bucket 16. Therefore, the operator
By looking at 107, the inclination angle of the bucket 16 can be easily known.

A is an operating device, and as shown in FIGS. 7 to 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 operating lever 58 can be operated in any direction as shown in FIG. 10 with the two axes of the horizontal shaft 62 and the front-rear shaft 63 orthogonal to each other as fulcrums. It is like this. 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, and is interlocked with the longitudinal movement of the operating lever 58 via the horizontal shaft 62,
In addition, a command signal having a voltage corresponding to the operation amount of the operation lever 58 is output. The second potentiometer 60 is for instructing the rotation of the bucket 16, is interlocked with the left and right movements of the operation lever 58 via the front-rear shaft 63 and the movable frame 61, and has a voltage corresponding to the operation amount of the operation lever 58. Output a command signal.

Push-button type automatic changeover switch on top of operation lever 58
64 is installed. A hemispherical operating portion 65 is provided at the lower end of the operating lever 58, and a bottom portion inside the case 57 is
A raising switch 66, a lowering switch 67, a dump switch 68, and a scooping switch 69 are provided on the front, rear, left, and right around the actuating portion 65. Each of these switches 66 to 69 is operated by the operating lever 58.
Is operated by the operating part 65 when the maximum amount of is operated. Incidentally, 70 is a flexible cover.

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 is 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, which is elevated when the operating lever 58 is operated in the upward direction. Discriminate the descent when the operation is negative in the negative direction. 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. Reference numeral 89 denotes an automatic manual switching circuit, which switches from manual to automatic when the automatic switching switch 64 of the operating lever 58 is pressed to turn it on, and the first deviation / amplification circuit 86 is generated by the rising signal from the rising / falling discrimination circuit 83.
Is selected to perform the posture holding control, and the descending signal selects the second deviation / amplification circuit 88 to perform the horizontal grounding control. 90 is a scoop / dump discrimination circuit,
The operation direction of the bucket 16 is discriminated 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 89 is positive, scoop and when it is negative, discriminate dump. 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 shown in FIG.
By rotating in the direction of the arrow, the first sensor 19 enters an inclined state as shown in FIG. 6, and outputs a negative voltage signal according to the inclination angle of the bucket 16 with respect to the ground.

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 ascending 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 rake / 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. 6, 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 16 is in the dumping state, the second rod is passed through the rod 45, the operation link 26, the horizontal shaft 22, etc.
The sensor 20 detects the tilt angle of the bucket 16 with respect to the boom 13, and the second deviation / amplification circuit 88 determines the deviation between the tilt signal at that time and the target value of the setting circuit 87. 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 is 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.

Since the first sensor 19 and the second sensor 20 are housed inside the sensor case 18, they do not come into contact with earth and sand and other obstacles, and reliability is significantly improved.

Further, the first sensor 19 for detecting the inclination angle of the bucket 16 with respect to the ground
And the second sensor 20 for detecting the inclination angle of the bucket 16 with respect to the boom 13 are arranged on the same axis of the horizontal shaft 22, and are linked to the bucket 16 via the operation link 26 and the rod 45. Is easy, especially for the motion system such as rod 45
There is an advantage that it can be shared by individuals. Also, since the rod 45 is arranged close to the upper edge side of the boom 13 and substantially parallel to it, there is little contact with obstacles, and even if it makes a contact, it is not greatly separated from the boom 13, so the rod 45 is slightly It can be deformed to a very small extent. Since the cover plate 23 closes the open end of the sensor case 18, it is difficult for dirt and the like to enter the sensor case 18.

Although the working link 26 and the bucket 16 are connected by the rod 45 in the embodiment, a push-pull cable or the like may be used. Further, instead of the bucket 16, a fork or the like may be attached as a work tool, and the present invention can be applied to not only the front loader but also a backhoe or the like.

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.

(Effect of the Invention) According to the present invention, on the rear side of the bracket 101 on the boom 13,
A sensor case 18 is provided, and a first sensor case 18 is provided in the sensor case 18.
Since the second sensor 19 and the second sensor 20 are stored, there is no fear that the sensor case 18 may interfere with other objects when the boom 13 is moved up and down and the worker 16 is dumped and tilted. The sensor case 18 can be installed by using a space that does not become a space, and the sensor case 18 can be easily attached by using the boom 13 or the bracket 101.
The sensor 19 and 20 can be reliably protected by 18,
The reliability of the sensors 19, 20 is improved.

The first sensor for detecting the inclination angle of the work implement 16 with respect to the ground
19 and a second sensor 20 for detecting the inclination angle of the work implement 16 with respect to the boom 13 are interlocked with the horizontal shaft 22, and the horizontal shaft 22 is interlocked with the work implement 16 via an operation link 26. Therefore, the working tool 16 and the operation link 26 are also used as an interlocking system,
Different types of detection signals can be taken out from the first and second sensors 19 and 20, and the structure can be simplified and the cost can be reduced. Moreover, since each sensor 19 and 20 only needs to detect the rotation angle of the operation link 26, it is not necessary to directly detect the cylinder stroke of the working tool cylinder 17 or the like, and an inexpensive sensor is used to improve control performance. The practical effect is remarkable.

[Brief description of drawings]

The drawings show an embodiment of the present invention. FIG. 1 is a side view of the whole, FIG. 2 is a side view of a sensor mounting portion, and FIG. 3 is a view taken along the line AA of FIG. 4 is a cross-sectional view of the first sensor, FIG. 6 is an explanatory view of the same operation, FIG. 7 is a rear view of the operating device, and FIG. 8 is the same. Sectional rear view, FIG. 9 is a view taken along the line CC of FIG. 8, FIG. 10 is a view taken along the line D-D of FIG. 8, FIG. 11 is an explanatory view of the operating position, and FIG. 12 is a hydraulic circuit. FIG. 13 is a control circuit diagram and FIG. 14 is a hydraulic circuit diagram. 1 ... tractor body, 8 ... front loader, 13 ... boom, 16 ... bucket, 18 ... sensor case, 19 ... first sensor, 20 ... second sensor, 22 ... horizontal axis, 26 ... … Actuating link, 45… Rod, 101… Bracket.

Claims (1)

[Scope of utility model registration request] 1. A boom 13 is rotatably supported by a horizontal shaft 12 on the vehicle body 1 side, and a work tool 16 is rotatably supported by a horizontal shaft 15 at the tip of the boom 13, and the boom 13 is rotatably supported. A bracket 101 is provided so as to project upward in the middle part thereof, and a work tool cylinder 17 for adjusting the angle of the work tool 16 is provided on the upper side of the boom 13 so as to connect the bracket 101 and the work tool 16. A first sensor 19 for detecting 16 ground tilt angles,
A boom-type working machine including a second sensor 20 for detecting an inclination angle of the work implement 16 with respect to the boom 13, and controlling the posture of the work implement 16 by signals from the first and second sensors 19 and 20. At the rear side of the bracket 101 on the boom 13, a sensor case 18 is provided, the first and second sensors 19 and 20 are stored in the sensor case 18, and the first and second sensors 19 are , 20 are linked to the horizontal axis 22, and this horizontal axis 22 is the operating link 2
A work implement posture detector for a boom type work machine, which is connected to a work implement 16 via 6.