JP2977725B2 - Work vehicle abnormality detection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention includes an actuator for driving and operating a driven portion provided on a body of a vehicle, and a position sensor for detecting an operation position of the actuator. The present invention relates to a configuration of an abnormality detection device for a position sensor of an actuator in a work vehicle provided with a control unit that performs control.

[0002]

2. Description of the Related Art In a work vehicle having an actuator and a position sensor as described above, the operation sensor is operated so that the actuator is positioned at a position corresponding to an operation command while detecting the operation position of the actuator by the position sensor. Is configured to
An example of such a work vehicle abnormality detection device is as follows.

Since the operating range of the actuator can be recognized in advance, the value detected by the position sensor when the actuator reaches the end of the operating range can also be recognized in advance. With this, when an operation command is issued to the actuator to operate to the end of the operation range, it is possible to visually confirm that the actuator is operating to the end of the operation range. If the detected value corresponding to the end of is not output, such a state does not occur if the position sensor is normal, and in such a case, it is determined that an abnormality has occurred in the position sensor.

[0004]

In the above-described abnormality detecting device, it is impossible to determine whether an abnormality has occurred in the position sensor unless the actuator is operated to the end of the operation range. Therefore, even if an abnormality has occurred in the position sensor, if the actuator continues to be operated only before the end of the operating range, the abnormality in the position sensor cannot be detected, and an error in the position sensor may be detected. The actuation operation of the actuator is performed based on this.
The present invention provides a work vehicle configured to operate an actuator based on a detection value of a position sensor, even if the actuator is operated only before an end of an operation range, whether or not the position sensor is abnormal. It is an object of the present invention to obtain an abnormality detection device capable of detecting the abnormality.

[0005]

A feature of the present invention resides in that the abnormality detecting device for a work vehicle as described above is configured as follows. A rate-of-change detecting means for detecting a rate of change of the detected value of the position sensor; and an upper-limit rate of change of the detected value corresponding to the upper limit of the operation speed of the actuator by the control means. Abnormality detecting means for determining that the sensor is abnormal.

[0006]

When the actuator is operated by the control means, the actuator cannot be operated by setting the operation speed of the actuator to the high speed side without any limitation. Therefore, the upper limit of the normal operation speed of the actuator must be recognized in advance. Can be. Thus, the operation speed of the actuator can be detected by determining the rate of change of the detection value of the position sensor that detects the operation position of the actuator.

Therefore, according to the first aspect of the present invention, even if the actuator is operated only up to the end of the operating range, the rate of change of the detection value of the position sensor corresponds to the operating speed of the actuator. If the value exceeds the upper limit change rate, such a state does not occur if the position sensor is normal, and in such a case, it is determined that the position sensor is abnormal.

[0008]

According to the first aspect of the present invention, in a work vehicle configured to operate the actuator based on the detection value of the position sensor, the actuator is operated only up to the end of the operation range. However, it is possible to obtain an abnormality detection device that can detect the presence / absence of an abnormality in the position sensor, and cannot operate the actuator based on an erroneous detection value of the position sensor without detecting the abnormality in the position sensor. It was possible to prevent work defects caused by performing the above.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. [1] FIG. 4 shows an entire side surface of a backhoe as an example of a working vehicle. A dozer 20 is supported on a traveling device 1 of a rubber crawler type, and a swivel 2 is supported on an upper portion. 3 (corresponding to a driven portion). The backhoe device 3 includes a boom 4 oscillated by a hydraulic cylinder 11 (corresponding to an actuator), a hydraulic cylinder 12
The arm 5 includes an arm 5 that is driven to swing by an actuator (corresponding to an actuator), and a bucket 6 that is driven to swing by a hydraulic cylinder 13 (corresponding to an actuator). A hydraulic motor 14 is provided for driving the turntable 2 to turn.

As shown in FIG. 4, the boom 4 of the backhoe device 3 has a first boom portion 4a connected to the revolving base 2 so as to be able to swing up and down, and a 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 second boom portion 4b includes a support bracket 4c that is swingably connected to the left and right around an axis P2 at the front end of the second boom portion 4b, and the arm 5 is connected to the support bracket 4c.
A link 4 is provided over the first boom portion 4a and the support bracket 4c to form a parallel quadruple link.
By swinging the second boom portion 4b with the hydraulic cylinder 7 (corresponding to an actuator), the arm 5 and the bucket 6 are moved left and right in parallel.

As shown in FIG. 5, 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 22 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 2. The control valves 21 to 25 are of a three-position switching type and of a pilot operation type, and the flow rate can be controlled by adjusting the opening based on the pilot pressure. Control valve 2
With respect to 1 to 25, pilot valves 31a, 31b of the electromagnetic proportional pressure reducing valve type for generating pilot pressure for opening degree operation,
32a, 32b, 33a, 33b, 34a, 34b, 3
5a and 35b are provided.

In this case, as shown in FIG. 6, a pulse signal output from the control device 19 according to the operation amount from the neutral position of the right and left operation levers 9, 10 and the operation pedal 26, which will be described later, is transmitted to the transistor 42. Via the pilot valve 31a
To the pilot valves 31a to 35a.
The control device 1 is configured to change the pilot pressure from the control device 1a, and to detect the feedback values from the potentiometers 36, 37, 38, and 39 described later as feedback.
9 is directly input.

As shown in FIGS. 5 and 3, the swivel 2 is provided with a right operating lever 9 and a left operating lever 10.
The right and left operation levers 9 and 10 are freely operable back and forth and left and right, and are provided with a potentiometer 15 for detecting a front and rear operation position of the right operation lever 9 and a potentiometer 16 for detecting a left and right operation position. A potentiometer 17 for detecting an operation position in the front-rear direction 10 and a potentiometer 18 for detecting an operation position in the left-right direction are provided, and operation signals from the respective potentiometers 15 to 18 are input to the control device 19. An operation pedal 26 is provided at a lower portion on the 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 configuration, when the right operating lever 9 is operated forward or backward, the pilot valves 31a, 3
1b generates a pilot pressure, the control valve 21 is operated to the lower side or the upper side of the first boom portion 4a, and when the control valve 21 is operated to the right or left, the pilot valves 33a and 33b generate the pilot pressure based on the operation, and the control valve 23 is operated on the earth discharging side or the scraping side of the bucket 6. When the left operation lever 10 is operated forward or backward, the pilot valves 32a, 32
2b generates a pilot pressure, the control valve 22 is operated on the raising side or the scraping side of the arm 5, and when the control valve 22 is operated on the right or left side, the pilot valves 34a and 34b generate the pilot pressure based on this, and the control valve 24 is operated. Operated to the right or left turning side. When the operation pedal 26 is depressed to the right or left, the pilot valves 35a and 35b generate pilot pressure 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 of the right and left operation levers 9 and 10 detect not only the operation directions of the right and left operation levers 9 and 10 but also the operation amount from the neutral position. As a result, the larger the operation amounts of the right and left operation levers 9 and 10 are, the larger the pilot valve 31a is.
The pilot pressures of .about.34b increase, and the control valves 21 to 24 are operated to the larger flow rate side. That is, the larger the right and left operation levers 9 and 10 are operated, the more the hydraulic cylinders 11 to 13
And the hydraulic motor 14 operates at high speed.

[2] Next, the first first setting before the setting for the operating unit 27 of the swivel 2 is performed.
The front second restraint surfaces A1 and A2 and the lateral restraint surface A3 will be described. As shown in FIG. 2 and FIG.
The backhoe device 3 is arranged on the right side, and the driver's seat 28 on the left side.
Unit 2 composed of right and left operation levers 9, 10 and the like
7 are arranged. As shown in FIGS. 2, 3, and 4, a partition wall 29 with a window that partitions the backhoe device 3 and the operation unit 27 is provided in the center of the swivel 2 at the left and right sides. A semicircular roof 30 along the outside is fixed.

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

As shown in FIGS. 1, 2 and 3, in a range above a predetermined position D above the swivel base 2, a partition wall 2 is provided.
The front first restraining surface A1 having a predetermined left and right width is set in the space at a predetermined distance away from the front edge 29a of the front edge 29a and a predetermined vertical width at a predetermined distance away from the front edge 30a of the roof 30. The front second restraining surface A2 having the following is set in the space so as to be continuous with the first front restraining surface A1. In a range above the predetermined position D, a surface that is outwardly separated by a predetermined distance from the front first and second front tread surfaces A1 and A2 is set, and the surface of this space and the front first and second front tread surfaces are set. A region between A1 and A2 is set as a front first restraint region B1 and a front second restraint region B2.

As shown in FIG. 3 and FIG. 2, a plane extending from the end of the front first restraint surface A1 on the side of the backhoe device 3 to the rear and a predetermined distance away from the partition wall 29 to the right of the paper of FIG. Is set in the space. Lateral check surface A
3 is set at a predetermined distance from FIG. 3 to the right in the drawing of FIG. 3, and a space between this space surface and the lateral restraint surface A3 is set as a lateral restraint region B3. The first and second front restraint surfaces A1 and A2, the first and second front restraint areas B as described above.
1, B2, the lateral restraint surface A3, and the lateral restraint area B3 are set with respect to the space of the swivel base 2;
Moves together with the swivel 2 as it turns.

[3] Next, the predetermined position D in FIGS. 1 and 2 will be described. As shown in FIG. 1, the bucket 6 is
By operating the second boom portion 4b by the hydraulic cylinder 7 so as to be located in front of the a, the arm 5 is operated to the scraping side to the end of the operation range, and the bucket 6 is operated to the earth discharging side. In a state where the tip of the bucket 6 and the arm 5 are operated so as to be linear (a state where the distance from the arm 5 to the tip of the bucket 6 is the longest), the first boom portion 4a
Is operated on the ascending side, the tip of the bucket 6 moves on the locus C.

In this case, the first boom portion 4 is kept in the above-described 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 moved upward is the predetermined position D, and the first boom portion 4a exceeds the predetermined position D.
Is moved upward, the tip of the bucket 6 is
Contacts the front edge 29a of the Conversely, even if the first boom portion 4a is operated downward from the predetermined position D in the aforementioned state, the tip of the bucket 6 does not contact the front edge 29a of the partition wall 29 and the swivel 2.

[4] Next, the control of the backhoe device 3 for the first and second front restraint surfaces A1, A2 and the first and second front restraint areas B1, B2 will be described. In the control device 19, the up-down angle of the first boom portion 4a, the left-right angle of the second boom portion 4b, the front-back angle of the arm 5 and the bucket 6 based on the detection values of the potentiometers 36 to 39, and the first boom portion 4
a, the position of the tip of the bucket 6 is constantly detected based on the length of the second boom portion 4b, the arm 5, and the bucket 6, and the detected values of the potentiometers 36 to 39 are differentiated to obtain the tip of the bucket 6. The moving direction and the moving speed of are detected.

When the tip of the bucket 6 is located in front of the partition wall 29 and the front edges 29a, 30a of the roof 30, the tip of the bucket 6 is located at the front first and second fronts in FIGS. When the vehicle enters the restraint areas B1 and B2, regardless of the operation of the right and left operation levers 9 and 10 and the operation pedal 26,
The operating speed of the hydraulic cylinders 7, 11, 12, 13 is reduced. In this case, the front end of the bucket 6 is located within the front first and second front restraint areas B1, B2.
The closer to the check surfaces A1, A2, the more the hydraulic cylinders 7, 1
1, 12, and 13 are greatly decelerated. Conversely, when the first boom portion 4a or the like is operated in a direction in which the tip of the bucket 6 moves away from the front first and second front restraint surfaces A1 and A2 in the front first and second restraint areas B1 and B2. Are hydraulic cylinders 7, 11, 12, 13 opposite to the aforementioned deceleration operation.
Is increased, and when the vehicle moves out of the first and second front restraint regions B1 and B2, the operation speed returns to the original operation speed.

It is assumed that the tip of the bucket 6 has reached the front first restraining surface A1 or the front second restraining surface A2. In this case, arm 5
The second boom portion 4b is moved to the left (operating section 27) regardless of whether the first boom portion 4a is moved upward or the first boom portion 4a is moved upward.
Side), the tip of the bucket 6 enters the driving unit 27 side beyond the front first or second front restraint surfaces A1 and B1.

Thus, with the tip of the bucket 6 reaching the first or second front restraint surface A1, A2, the left operating lever 10 is used to operate the arm 5 to the scraping side, and the right operating lever 9 is operated.
To move the first boom portion 4a upward, the tip of the bucket 6 to the entry side of the front first or second front restraint surfaces A1, A2, and the second boom portion 4b to the left with the operation pedal 26, or the bucket 6 First or front second check surface A1, A at the tip of
The pilot valve 31a to 33b, 35
a, 35b the pilot pressure disappears and the control valves 21, 22,
23, 25, hydraulic cylinders 7, 11, 12, 13
Is stopped (corresponding to control means). Conversely, in a state where the tip of the bucket 6 has reached the front first or second front restraint surface A1, A2, the operation of the arm 5 to the raising side, the operation of the first boom portion 4a to the lowering side, the tip of the bucket 6 The operation on the side away from the first or second front restraint surface A1, A2 and the operation on the right side of the second boom portion 4b are performed when the tip of the bucket 6 has the front first or second front restraint surface A1, A2. These operations can be performed without hindrance because the operations are away from the camera.

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 around the axis P1 of the first boom portion 4a (to the side of the driving section 27) in a state in which the first boom portion 4a is located in front of 9a.
If the tip of the bucket 6 does not touch the front first restraint surface A1,
The second boom portion 4b can be operated to the left (to the driving section 27). This is because the lateral side of the front first restraint surface A1 on the side of the driving unit 27 is a space in which there is nothing to which the tip of the bucket 6 comes into contact. When the second boom portion 4b is operated to the left (toward the operation unit 27) near the lower end of the front first restraint surface A1 (near the predetermined position D), the tip of the bucket 6 is moved to the operation unit 27 shown in FIGS. Guard frame 40
(Connected between the middle of the front edge 29a of the partition wall 29 and the swivel 2), the guard frame 40 and the operation lever 41 of the traveling The position has been set.

[5] Next, as shown in FIG.
When the first boom portion 4a is operated up and down in a state where the bucket 6 is positioned in front of the front edge 29a of the partition wall 29 as described above, the tip of the bucket 6 Moves on the locus C, so that the tip of the bucket 6 is moved forward by the front edge 29a of the partition wall 29 and the swivel 2
Never touch.

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

[6] Next, the control of the backhoe device 3 for the lateral restraint surface A3 and the lateral restraint area B3 will be described. In the control device 19, as described above, the vertical angle of the first boom portion 4a based on the detection values of the potentiometers 36 to 39, the second boom portion 4
b, the front and rear angles of the arm 5 and the bucket 6,
The position of the left side surface of the bucket 6 is constantly detected by the lengths of the first boom portion 4a, the second boom portion 4b, the arm 5, and the bucket 6, and the potentiometers 36 to 3
The moving direction and the moving speed of the left lateral side of the bucket 6 are detected by differentiating the detected value of No. 9.

As shown in FIGS. 2 and 3, when the bucket 6 is located on the right side of the operation unit 27, the second boom part 4b is operated by the hydraulic cylinder 7 toward the operation unit 27, and the bucket 6 When the left lateral side of the vehicle enters the lateral restraint region B3, the pilot valves 35a and 35b are operated, and the operation speed of the hydraulic cylinder 7 of the second boom portion 4b is reduced regardless of the operation of the operation pedal 26. in this case,
The more the left lateral side of the bucket 6 enters the lateral restraint area B3 and approaches the lateral restraint surface A3, the greater the deceleration operation is performed.

Conversely, the left lateral side of the bucket 6 is the lateral restraint surface A.
When the second boom portion 4b is operated in a direction away from the third boom portion 3, the operating speed of the hydraulic cylinder 7 of the second boom portion 4b is increased in the lateral restraint region B3, contrary to the aforementioned deceleration operation. When the vehicle exits the lateral restraint area B3, it returns to the original operating speed. The left lateral side of the bucket 6 reaches the lateral restraint surface A3, and slightly exceeds the lateral restraint surface A3.
Side valve, the pilot valve 35
The pilot pressures a and 35b disappear, and the control valve 25 stops the hydraulic cylinder 7 of the second boom portion 4b (this corresponds to the control means).

[7] Next, regarding the abnormality detection device (installed in the control device 19) of the potentiometers 36, 37, 38, and 39 of the hydraulic cylinders 7, 11, 12, and 13, the boom 4 (the first boom portion 4a) The potentiometer 36 of the hydraulic cylinder 11 will be described as a representative. As shown in FIG. 7, it is assumed that the operator operates the right operation lever 9 forward or backward (step S <b> 1) to perform the expansion / contraction operation of the hydraulic cylinder 11 (operation of moving the boom 4 upward and downward). In this case, the hydraulic cylinder 1
If the relief valve 1 (not shown) is not opened, the operating position of the hydraulic cylinder 11 can be determined to be in the middle of the operating range (step S2), and the change rate E of the detection value of the potentiometer 36 at this time is detected. (Step S3)
(Corresponding to a change rate detecting means).

Since the upper limit of the operating speed of the hydraulic cylinder 11 in the normal state is determined, the rate of change of the detection value of the potentiometer 36 corresponding to the upper limit of the operating speed is also
It is recognized in advance as the upper limit change rate E1. Therefore,
If the potentiometer 36 is normal, the change rate E of the detection value of the potentiometer 36 is always equal to or less than the upper limit change rate E1. Thus, when the change rate E of the detection value of the potentiometer 36 is detected as described above, the change rate E is compared with the upper limit change rate E1 (step S1).
4) If the change rate E is equal to or smaller than the upper limit change rate E1, it can be determined that the potentiometer 36 is normal. Conversely, if the rate of change E is greater than the upper limit rate of change E1, it is determined that an abnormality has occurred in the potentiometer 36 (step S6) (corresponding to abnormality detection means).

If the change rate E is small due to the abnormality while the abnormality has occurred in the potentiometer 36, the abnormality of the potentiometer 36 cannot be detected in step S4. Thus, the abnormality of the potentiometer 36 is detected. As shown in FIG. 7, it is assumed that the operator operates the right operation lever 9 forward (step S1) to perform the contracting operation of the hydraulic cylinder 11 (the operation of moving the boom 4 down). In this case, when the relief valve (not shown) of the hydraulic cylinder 11 is opened, it can be determined that the operating position of the hydraulic cylinder 11 has reached the end of the operating range (Step S2).

In a normal state, the value detected by the potentiometer 36 when the operating position of the hydraulic cylinder 11 reaches the end of the operating range is recognized in advance as a set value. Therefore, if the potentiometer 36 is normal, when the operating position of the hydraulic cylinder 11 reaches the end of the operating range, the detection value of the potentiometer 36 becomes substantially equal to the set value. As a result, when it is determined that the relief valve (not shown) of the hydraulic cylinder 11 has opened and the operating position of the hydraulic cylinder 11 has reached the end of the operating range, the detection value of the potentiometer 36 is compared with the set value. Then, if the detected value is substantially equal to the set value (step S5), it is determined that the potentiometer 36 is normal. Conversely, if the detected value deviates from the set value to the large side or the small side, it is determined that an abnormality has occurred in the potentiometer 36 (Step S).
6). The abnormality detection performed as described above is performed by the potentiometers 37, 3 of the other hydraulic cylinders 7, 12, 13.
The same applies to 8, 39.

[Alternative Embodiment] In the above-described embodiment, the operating positions of the hydraulic cylinders 7, 11, 12, 13 are detected by detecting the vertical angle and the like of the first boom portion 4a with the potentiometers 36, 37, 38, 39. However, a linear actuation type potentiometer is directly attached to the hydraulic cylinders 7, 11, 12, 13 to detect the operating positions of the hydraulic cylinders 7, 11, 12, 13. May be.

Incidentally, reference numerals are written in the claims for convenience of comparison with the drawings, but the present invention is not limited to the configuration of the attached drawings by the entry.

[Brief description of the drawings]

FIG. 1 is a schematic side view of a backhoe showing front first and second restraint surfaces, and first and second front restraint areas.

FIG. 2 is a schematic front view of a backhoe showing front first and second front restraint surfaces, front first and second front restraint regions, a lateral restraint surface, and a horizontal restraint region.

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

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

FIG. 5 shows each hydraulic cylinder, control valve,
Diagram showing the relationship between the pilot valve, right and left operating levers, etc.

FIG. 6 is a circuit diagram of an operation system of one pilot valve.

FIG. 7 is a diagram showing a flow of abnormality detection in the abnormality detection device.

[Explanation of symbols]

 3 Driven part 7, 11, 12, 13 Actuator 36, 37, 38, 39 Position sensor E Change rate E1 Upper limit change rate

Claims (1)

(57) [Claims] An actuator (7) for driving and operating a driven part (3) provided in a body of the vehicle.
(13) and the actuators (7), (11),
(12), a position sensor (36), (37), (38), (39) for detecting the operating position of (13),
The position sensors (36), (37), (38), (3)
Based on the detected value of 9), the actuator (7),
An abnormality detection device for a working vehicle, comprising: control means for operating and operating (11), (12) and (13), wherein the position sensors (36), (37), (38) and (3)
9) a change rate detecting means for detecting a change rate (E) of the detection value, and the actuator (7),
Corresponds to the upper limit of the operating speed of (11), (12) and (13)
When the change rate (E) of the detected value of the position sensors (36), (37), (38), and (39) exceeds the upper limit change rate (E1) of the detected value, the position sensor (3) is detected.
6) An abnormality detection device for a working vehicle, comprising: abnormality detection means for judging an abnormality of (37), (38), or (39).