JP3174279B2 - Construction machine with bucket - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a construction machine with a bucket such as a backhoe.

[0002]

2. Description of the Related Art In a construction machine with a bucket such as a backhoe, a boom is pivotally supported at the front of the body so as to be vertically swingable, and an arm is pivotally supported at the tip of the boom so as to be able to swing back and forth. The pivot is pivotally supported on the bucket. The boom is moved up and down by a boom cylinder, the arm is bent and extended by an arm cylinder, and the bucket is swung by a bucket cylinder to perform a scraping operation or a dumping operation.

[0003] In this type of construction machine, for example, when the body is parked at a fixed position and horizontal excavation is performed from a side far from the body toward the front side, or the ground is leveled in a reverse direction. , Boom, arm and bucket 3
It is necessary to perform the control by combining the two swings in a complex manner. To facilitate such control and automation, the boom angle formed by the boom with respect to the aircraft and the arm angle formed by the arm with respect to the boom An angle detector such as a potentiometer detects a bucket angle formed by a bucket with respect to an arm, and controls a hydraulic circuit based on these detected angles to swing the boom, arm, and bucket. is there.

[0004]

As described above, the angle detector for detecting the bucket angle is usually attached to the pivoting support portion of the bucket at the tip of the arm. Is exposed to adverse conditions such as direct vibration, impact, or submersion of water, and thus there is a problem that the possibility of failure is higher than that of an angle detector that detects a boom angle or an arm angle.

As described above, if the angle detector breaks down, the detection of the bucket angle naturally becomes unreliable, and in some cases, the angle cannot be detected. Excavation could not be performed at the excavation depth, or excavation could not be performed at the optimal bucket claw position, and there was a possibility that the work would be adversely affected.

Although it is possible to detect the bucket angle by using a bucket cylinder having a stroke sensor inside to avoid the above-mentioned adverse effects due to the clod, etc., such a bucket cylinder can be used. Is very expensive, which leads to an increase in the cost of construction machinery. The present invention has been made in view of the above circumstances, and makes it possible to obtain high reliability in detection of a bucket angle, to ensure easy and automatic steering, and not to impair workability. It is an object of the present invention to provide a construction machine with a bucket.

[0007]

According to the present invention, the following technical measures have been taken in order to achieve the above object. That is, the present invention relates to a construction machine with a bucket in which a bucket is pivotally supported on a body via a boom and an arm, and a bucket cylinder used for rocking the bucket is pivotally supported on the arm. An angle detector for detecting an angle of the bucket cylinder with respect to the arm is provided at a pivot portion of the bucket cylinder to the arm, and the angle of the bucket cylinder detected by the angle detector is set to a value corresponding to the angle. Conversion means for converting the angle of the bucket corresponding to the angle of the bucket into two angles, and when the angle of the bucket corresponding to the angle of the bucket cylinder takes two values, a determination means for determining a normal bucket angle from the two values is provided. And

According to this, the angle detector is provided on the pivot portion of the bucket cylinder remote from the work area of the bucket to the arm, so that the angle of the bucket is obtained from the angle of the bucket cylinder with respect to the arm via the conversion means. Therefore, the angle detector is less affected by vibration, impact, submersion, and the like. Because of this, the angle detector that detects the bucket angle is less likely to be damaged.
High reliability is obtained in the detected value of the bucket angle, facilitating easy operation and automation, ensuring accurate bucket depth and optimal bucket claw position for automatic horizontal excavation. It is possible to improve workability.

In some cases, the angle of the bucket corresponding to the angle of the bucket cylinder takes two values. By discriminating this, the correct bucket angle can be obtained. The determination means may determine the bucket angle based on the swing direction of the bucket and the state of increase or decrease in the angle of the bucket cylinder. Based on the length, the bucket angle may be determined based on whether the bucket cylinder is in an extended state or a contracted state.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. As shown in FIG. 5, a construction machine 1 such as a backhoe includes a pair of left and right crawler traveling devices 2 and a substantially circular swivel 3 mounted on the crawler traveling devices 2 so as to be rotatable around a vertical axis. 4 and the turntable 3
The excavator 5 is mounted on the front right side of the vehicle, the control box 6 is disposed on the upper left side of the front, the driver's seat 7 is disposed behind the control box 6, and the dozer 8 protrudes forward of the crawler traveling device 2. It is configured.

The excavator 5 is supported by the swivel 3 so as to be able to swing up and down, and is swung by a boom cylinder 9, and a distal end of the boom 10 via a left-right arm support shaft 11. An arm 13 is connected and oscillated by the arm cylinder 12, and has a bucket 16 connected to a tip of the arm 13 via a bucket support shaft 14 extending in the left-right direction and driven by the bucket cylinder 15 for dumping and dumping. .

As shown in FIG. 1, the bottom side 15a of the bucket cylinder 15 is positioned near the base end of the arm 13 (on the side opposite to the pivot end of the bucket 16) via a left-right cylinder support shaft 18. The tip of the rod 15 b is connected to the tip of the bucket 16 and the arm 13 via a bucket link 19.

An engine 21 is mounted at the rear of the swivel 3 and a radiator is arranged on one side of the engine 21.
On the other side, a hydraulic pump 22 is provided. And, inside the front side of the swivel 3, the boom cylinder 9, the arm cylinder 12, the bucket cylinder 15 and the swivel 3
A control valve block 23 formed by stacking control valves for the swing motor is provided. In the control box 6, a plurality of control valves for operating the control valves corresponding to the respective control valves are stacked. Operating valve block 25 is provided.
The hydraulic pump 22 supplies hydraulic oil to the control valve and the operation valve.

Each of the operation valves constituting the operation valve block 25 is switched by front and rear and left and right swings of two operation levers 27, and is used for the boom cylinder 9 constituting the control valve block 23 via a pilot oil passage. Each control valve for the arm cylinder 12, the bucket cylinder 15, and the swing motor can be controlled and operated. As shown in FIG. 3, a pressure switch 29 is provided in a pilot oil passage 28 connecting the operation valve 26 for the bucket cylinder 15 and the control valve 24.
Is provided. Accordingly, when the operation valve 26 for the bucket cylinder 15 is opened by the operation of the operation lever 27, the pressure in the pilot oil passage 28 on either the squeezing operation side or the dump operation side of the bucket 16 rises and the control valve 24, the pressure switch 29 detects whether the user is operating the scraping operation or the dumping operation (whether the bucket 16 swings in the scraping direction or the dumping direction). I have.

The swing direction of the bucket 16 is provided with a limit switch, a proximity switch 30 and the like for directly detecting the movement of the lever 27 in response to the left-right or front-back swing of the operation lever 27. May be detectable. An angle detector 31 such as a potentiometer is provided on a pivotal support portion (cylinder support shaft 18 portion) of the bucket cylinder 15 on the arm 13 side. This angle detector 31
Is designed to detect the angle of the bucket cylinder 15 with respect to the arm 13 about the cylinder support shaft 18 when the bucket cylinder 15 is extended and retracted to swing the bucket 16.

In the illustrated example, a line connecting the cylinder support shaft 18 of the bucket cylinder 15 and the bucket support shaft 14 of the bucket 16 is defined as a reference line X of the arm 13 and an angle β formed by the bucket cylinder with respect to this reference line X. (Hereinafter, referred to as a cylinder angle) is detected by the angle detector 31. The angle of the bucket 16 with respect to the arm 13 (hereinafter referred to as bucket angle α) is determined by the bucket spindle 1 of the bucket 16.
An angle α formed by a line segment connecting the front end 4 and the tip of the bucket claw 16 a with respect to the reference line X of the arm 13 is shown.

In the construction machine 1 according to the present invention,
Conversion means is provided for converting the cylinder angle β detected by the angle detector 31 into a bucket angle α corresponding to the cylinder angle β. As shown in FIG.
Is swung from the state shown in FIG. 1A (dump position) to the state shown in FIG. 1C (scraping position) via the state shown in FIG. 1B, the bucket angles are α1, α2, α3. , While the cylinder angle increases from β1 to β2 and then decreases from β2 to β3.

The change in the cylinder angle β and the bucket angle α is caused by the expansion and contraction of the bucket cylinder 15, which causes the bucket link 19 to rotate up and down around the pivotal support portion with respect to the arm 13. This is because the pivoting portion between the bucket link 19 and the bucket cylinder 15 moves up and down, and the bucket cylinder 15 reciprocates up and down by the movement of the bucket 16 in one direction.

Therefore, as shown in FIG. 2, the bucket angle α and the cylinder angle β are curved such that the cylinder angle β is plotted on the vertical axis and the bucket angle α is plotted on the horizontal axis. , And always take a corresponding value with a predetermined relationship, and such a relationship is used as conversion means. Then, as shown in FIG. 3, the cylinder angle β detected by the angle detector 31 is input to the first memory 34 of the calculation unit 33. The conversion program from the cylinder angle β to the bucket angle α as described above is stored in the second memory 35 of the calculation unit 33. Therefore, when the conversion program is read out to the processing device 36 of the calculation unit 33 and the detection value is input from the angle detector 31, the bucket angle α is calculated based on the relationship shown in FIG. I have.

As shown in FIG. 2, when the cylinder angle β becomes the maximum angle β2 shown in FIG. 1B, the bucket angle corresponding to this becomes one value α2. The conversion means can calculate an accurate bucket angle α corresponding to the cylinder angle β. However, an angle β1 (= β1) in which the cylinder angle β is smaller than the maximum angle β2 shown in FIG.
In the case of (3), since the bucket angle corresponding to the value can take two values α1 and α3, it is necessary to determine which of these two values is normal.

Therefore, the construction machine according to the present invention is provided with a discriminating means for discriminating the normal bucket angle α from these two values, which includes the swinging direction of the bucket 16 (detected by the pressure switch 29) and the cylinder angle. The bucket angle α is determined based on the increase / decrease state of β (detection by the angle detector 31). That is,
1 and 2, when the cylinder angle is β1 (= β3), the bucket 16 operates in the squeezing direction from the dump position (the bucket angle α increases), and the cylinder angle β is in an increasing state. (Arrow A), the bucket angle is determined to be α1 out of α1 and α3 (FIG. 1A).
State). Also, when the bucket 16 moves in the dumping direction from the scraping position (the bucket angle α decreases) and the cylinder angle β is in a decreasing state (arrow B), the bucket angle is also determined to be α1. .

Conversely, if the bucket 16 moves in the dumping direction from the scraping position (bucket angle α decreases) and the cylinder angle β is in an increasing state (arrow C), the bucket angle is α3. (The state of FIG. 1C),
When the bucket moves from the dump position in the scraping direction (the bucket angle α increases) and the cylinder angle β is in the decreasing state (arrow D), the bucket angle is determined to be α3. I have.

The bucket 1 by the pressure switch 29
6 and the information on the increase or decrease of the cylinder angle β by the angle detector 31 are input to the first memory 34 together with the cylinder angle β by the arithmetic unit 33, and the processing unit 3
The arithmetic processing is performed in step S6. By performing the above-described conversion and determination, the bucket angle α can be accurately obtained from the cylinder angle β, and this bucket angle α
Is used as one of the control factors for controlling the position of the bucket 16 together with the detected value of the boom angle formed by the boom 10 with respect to the body 4 and the arm angle formed by the arm 13 with respect to the boom 10. be able to. Therefore,
When performing automatic horizontal excavation or the like, an accurate bucket depth and an optimal bucket claw position can be obtained, and the excavation workability can be improved.

The arm 1 of the bucket cylinder 15
By providing the angle detector 31 at the pivot portion to the arm 3, the bucket 16 is arranged at a position farther from the working area of the bucket 16 than when the angle detector is provided at the swing pivot portion of the bucket 16 with respect to the arm 13. And during the operation of the bucket,
It is less likely that direct vibration or impact or submergence or the like will cause the angle detector 31 to malfunction. Therefore, the durability of the angle detector 31 is improved, and the reliability of the bucket angle detection is improved.

The calculated bucket angle α is stored in the rewritable and erasable third memory 37 composed of a nonvolatile RAM, an EEPROM, or the like in the arithmetic section 33. Therefore, the previous data is not erased when the power is turned off, and when the power is turned on again, the stored previous data is used for calculating a new bucket angle.

When the bucket 16 is not operated due to interruption of the work or the like, the bucket 16 may swing by its own weight due to a leak of a hydraulic circuit or the like. However, since the swing is not caused by the operation lever 27, the swing direction of the bucket 16 cannot be detected by the pressure switch 29. Therefore, the swing by the own weight causes the bucket cylinder 1 to swing.
Even if the angle of No. 5 changes, the problem that the above-described bucket angle α cannot be determined occurs.

In this case, as shown in FIG. 2, when the cylinder angle β before swinging by its own weight is smaller than the maximum angle β2 (eg, β1), the bucket angle before swinging (eg, α1). Therefore, it is easy to calculate a new bucket angle α from the cylinder angle β after swinging depending on whether the cylinder angle β has increased or decreased due to the self-weight swing of the bucket 16,
When the cylinder angle β before swinging is the maximum angle β2, the cylinder angle β only decreases due to its own weight swing, so it can be determined whether the bucket 16 has swung in the scraping direction or the dumping direction. Disappears.

Therefore, in this embodiment, the direction of the swing of the bucket 16 by its own weight is determined using the bucket angle α before the bucket 16 swings by its own weight, the arm angle, and the boom angle.
An accurate bucket angle α is obtained from this information and the cylinder angle β after swinging. Specifically, as shown in FIG. 4, when the angle γ formed by the line connecting the bucket support shaft 14 of the bucket 16 and the center of gravity G of the bucket 16 to the vertical direction Y is positive, that is, in FIG. Center of gravity G of bucket 16
However, when it is on the left side of the vertical line Y passing through the bucket support shaft 14, it can be determined that the bucket 16 has swung in the scraping direction (arrow E) due to its own weight. When γ is negative, that is, when the center of gravity G of the bucket 16 is on the right side of the vertical line Y (two-dot chain line), the bucket 16
Has been swung in the dump direction (arrow F). Therefore, the swing direction of the bucket 16 determined in this way and
A new bucket angle α can be calculated from the cylinder angle β after the swing.

The vertical line Y can be set from the boom angle and the arm angle. The angle γ between the bucket center of gravity G and the vertical line Y is set based on the bucket angle α before swing and the vertical line Y. Further, the bucket center of gravity G may be set as the center of gravity of the bucket 16 itself, set as the center of gravity in a state where earth and sand are scooped by the bucket, or the average position thereof may be set as the center of gravity G in consideration of both positions of the center of gravity.

FIGS. 6 and 7 show a second embodiment of the present invention. In the present embodiment, when the bucket angle α corresponding to the cylinder angle β takes two values, this determination is made based on the extension / contraction state of the rod 15b of the bucket cylinder 15. On the bottom 15a side of the bucket cylinder 15, a sensor 40 such as a proximity switch or a limit switch is provided.
Is provided on the rod 15b side.

The sensor 40 and the sensitive plate 41 move the bucket cylinder 15 in the contracted state based on the extension / contraction position of the rod 15b of the bucket cylinder 15 when the cylinder angle β takes the maximum β2 (see FIG. 6B). In some cases (when the bucket 16 is at the dump position), the sensor 40 is turned on, and when it is in the extended state (when the bucket 16 is at the scraping position), the sensor 41 is turned off. In addition, the information of ON / OFF of the sensor 40 is input to the first memory 34 of the calculation unit 33 instead of the swing direction of the bucket 16 and the increase / decrease state of the cylinder angle β in the first embodiment. It has become.

Therefore, in the correspondence diagram between the cylinder angle β and the bucket angle α shown in FIG.
2, the bucket angle α2 is obtained only by the conversion means as in the first embodiment, and the bucket angle corresponding to the cylinder angle (β1 = β3) is a binary α.
In the case of taking 1, α3, when the sensor 40 is on, it is determined that the bucket angle is α1, and the sensor 4
When 0 is off, it is determined that the bucket angle is α3.

As described above, also in this embodiment, an accurate bucket angle α can be obtained from the cylinder angle β, and the same effect as that of the first embodiment can be obtained. Can be used to determine the bucket angle α, so that the arithmetic processing can be simplified. Incidentally, the present invention is not limited to the above embodiment.

For example, the angle detector 31 for detecting the cylinder angle β can be replaced with an optical sensor or a mechanical contact type switch. The construction machine 1 is not limited to a so-called ultra-small turning backhoe as illustrated in the above-described embodiment, but is particularly limited as long as it has a bucket such as a so-called small turning backhoe, a power shovel, a front loader, and the like. Not something.

[0035]

As is apparent from the above description, according to the present invention, high reliability can be obtained in the detection of the bucket angle, so that the steering can be easily performed and the automation can be reliably performed, and the accurate bucket operation can be performed. Since the depth and the optimal position of the bucket claw for excavation can be obtained, the workability can be improved.

[Brief description of the drawings]

FIG. 1 is a side view showing a bucket and an arm portion according to a first embodiment of the present invention.

FIG. 2 is a correspondence diagram between the cylinder angle and the arm angle.

FIG. 3 is a diagram schematically showing the hydraulic circuit and a calculation unit.

FIG. 4 is a side view showing the bucket and arm.

FIG. 5 is a side view illustrating an example of a construction machine.

FIG. 6 is a side view showing a bucket and an arm portion according to a second embodiment of the present invention.

FIG. 7 is a correspondence diagram between the cylinder angle and the bucket angle.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Construction machine 4 Airframe 10 Boom 13 Arm 15 Bucket cylinder 16 Bucket 18 Cylinder support shaft 31 Angle detector

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) E02F 9/26 G01B 21/22

Claims (3)

(57) [Claims] 1. A bucket-equipped construction machine in which a bucket is swingably supported by a body via a boom and an arm, and a bucket cylinder used for swinging the bucket is swingably supported by the arm. An angle detector for detecting an angle of the bucket cylinder with respect to the arm is provided at a pivot portion of the bucket cylinder with respect to the arm, and the angle of the bucket cylinder detected by the angle detector is set to a value corresponding to the angle. Conversion means for converting the angle of the bucket corresponding to the angle of the bucket into two angles, and when the angle of the bucket corresponding to the angle of the bucket cylinder takes two values, a determination means for determining a normal bucket angle from the two values is provided. Construction machine with bucket. 2. The apparatus according to claim 1, wherein said determining means is configured to determine a legitimate bucket angle based on a swing direction of the bucket and an increase / decrease state of a bucket cylinder angle. A construction machine with a bucket according to item 1. 3. The normal bucket based on whether the bucket cylinder is in an extended state or a contracted state based on a length of expansion and contraction of the bucket cylinder when the angle of the bucket cylinder is the maximum angle. 2. The apparatus according to claim 1, wherein the angle is determined.
A construction machine with a bucket according to item 1.