JPH09113259A - Angle detecting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect the angle of rotation of a front attachment with accuracy. SOLUTION: An angle detecting device is provided with a lever 4 the one end of which is fixed to the bearing 2 of a rotating shaft 1 and the other end of which is engaged with a boom, etc., and the lever 4 can turn around the rotating shaft 1. On the backside of the shaft 1, an angle detector 5 composed of a potentiometer, etc., which detected the angle change of the lever 4 is provided. The bearing 2 can rotate around the shaft 1 together with the lever 4 in one body and a cam surface 2a is formed on the outer peripheral surface of the bearing 2. A position detector 6 is provided beside the bearing 2 and a limit switch 6a is attached to the front end section of the detector 6. When the lever 4 is turned by turning the boom, etc., the outer peripheral surface of the bearing 2 rotates while the surface is in contact with the front end of the switch 6a and, when the cam surface 2a of the shaft 2a comes into contact with the switch 6a, the switch 6a is pushed and turned on from a turned-off state.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an angle detecting device used in various working machines such as hydraulic excavators, and in particular, ultra-small swing hydraulic excavators.

[0002]

2. Description of the Related Art Working machines such as hydraulic excavators are equipped with booms,
An angle detection device for detecting the angle of the front attachment such as the arm and the bucket is provided. One angle detection device is provided for each rotation of the boom or arm in one direction, and is usually attached to the base of the front attachment. FIG. 5A is a front view of a conventional angle detection device, and FIG. 5B is a side view. As shown,
The conventional angle detection device includes a lever 4 having one end fixed to the bearing 2 of the rotary shaft 1 and the other end engaged with a front attachment 3 such as a boom. The lever 4 rotates around the rotary shaft 1. It is possible. An angle detector 5 including a potentiometer for detecting an angle change of the lever 4 is provided on the back side of the bearing 2. As a structure of this type of angle detector 5, a structure using a contact type resistance is widely known. The angle data detected by the angle detector 5 is sent in the form of an electric signal to a control device composed of a CPU or the like, and the control device controls the front attachment 3 based on the angle data.

[0003]

However, when the angle detector 5 using the contact type resistance is used, the resistance contact portion inside the angle detector 5 is abraded while the front attachment 3 repeats the change of the angle, and the angle detection 5 The accuracy may decrease. Further, the detected angle may change due to external vibration. For this reason, conventionally, a new angle detector is installed at another location, and the angle detection values of both angle detectors are compared under a predetermined condition to correct the angle detection value, or the boom is used as a reference. Correction work such as setting the angle and correcting the angle detection value of the angle detector at that time was performed. In this case, since it is necessary for the operator to perform the correction work by himself, in order to achieve automation, there was no choice but to provide a plurality of angle detectors as in. In this case, there is a problem in that since the characteristics vary among the machines due to the mounting error of the angle detectors and the like, the correction method must be changed for each machine, and the correction work is very troublesome. Further, even when a non-contact type angle detector is used, the angle of the front attachment 3 cannot be detected with high accuracy because it is the same in that it is affected by mounting errors and the like.

An object of the present invention is to provide an angle detecting device capable of accurately detecting the angle of a front attachment such as a boom with a simple means.

[0005]

The present invention will be described with reference to FIG. 1 showing an embodiment of the present invention. The present invention relates to a lever 4 attached to a front attachment 3 of a working machine, and a lever 4 of the lever 4. The present invention is applied to an angle detection device equipped with a bearing member 2 attached to one end and rotatable integrally with a lever 4 around an axis 1, and an angle detector 5 for detecting a rotation angle of the lever 4, and an outer circumference of the bearing member 2. A cam surface 2a is formed at a predetermined position on the surface, and a lever angle determining means for determining whether or not the rotation angle of the lever 4 is equal to or larger than a predetermined angle based on the rotational position of the cam surface 2a is provided. Is achieved. According to the first aspect of the invention, the cam surface 2a is formed at a predetermined position on the outer peripheral surface of the bearing 2 that rotates integrally with the lever 4 attached to the front attachment 3, and the rotation of the cam surface 2a causes the rotation of the lever 4 to rotate. It is determined whether the angle has become equal to or greater than a predetermined angle. That is, the rotation position of the cam surface 2a when the rotation angle of the lever 4 reaches a predetermined angle is detected by a limit switch or the like.

According to a second aspect of the present invention, the cam surface contact detecting means 6 is provided at a predetermined position capable of contacting the cam surface 2a and detects the presence or absence of contact of the cam surface 2a. When the contact of the cam surface 2a is detected by 6, the lever angle determination means is configured to determine that the rotation angle of the lever 4 has reached a predetermined angle. According to the second aspect of the present invention, a predetermined position at which the cam surface 2a can be contacted, that is, the rotational position of the cam surface 2a when the rotation angle of the lever 4 reaches a predetermined angle, is detected by a cam surface contact detection device including a limit switch. It is detected by means 6.

According to a third aspect of the present invention, the lever angle determination means determines that the rotation angle of the lever 4 has reached a predetermined angle, and the rotation angle of the lever 4 detected by the angle detector 5 and the predetermined angle. A deviation amount calculating means for calculating a deviation amount between the angle and the angle and an angle correction means for correcting the rotation angle of the lever 4 detected by the angle detector 5 based on the deviation amount. According to the third aspect of the present invention, since the lever angle determination means can accurately detect whether or not the rotation angle of the lever 4 has reached the predetermined angle, at the time when it is determined that the rotation angle of the lever 4 has reached the predetermined angle. Then, the deviation amount between the rotation angle of the lever 4 detected by the angle detector 5 and the predetermined angle is calculated. Then, thereafter, the detection result by the angle detection means is corrected using this shift amount.

Incidentally, in the section of means for solving the above problems for explaining the constitution of the present invention, the drawings of one embodiment of the present invention are used for making the present invention easy to understand. Is not limited to the one embodiment.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to FIGS. 1 (a), 2
FIG. 1A is a front view of an embodiment of an angle detection device according to the present invention, and FIGS. 1B and 2B are side views, showing components common to the conventional angle detection device shown in FIG. Are given the same reference numerals. The angle detecting device according to the present embodiment includes a lever 4 having one end fixed to the bearing 2 of the rotary shaft 1 and the other end engaged with the front attachment 3 such as a boom, as in the conventional angle detecting device. The lever 4 is rotatable around the rotary shaft 1. Further, the angle detector 5 including a potentiometer or the like for detecting the angle change of the lever 4 is provided on the back side of the rotary shaft 1 in common with the conventional angle detector.

The bearing 2 is rotatable together with the lever 4 around the rotary shaft 1, and a cam surface 2a is formed at a predetermined position on the outer peripheral surface of the bearing 2. A position detector 6 is arranged beside the bearing 2, and a limit switch 6a is attached to the tip of the position detector 6. When the lever 4 is rotated by the rotation of the front attachment 3,
2 (a) and 1 (b), when the outer peripheral surface of the bearing 2 rotates while contacting the tip of the limit switch 6a, and the cam surface 2a of the rotary shaft 1 contacts the limit switch 6a, as shown in FIG. As shown in a) and 2 (b), the limit switch 6a is pushed to switch the limit switch 6a from off to on. Since the cam surface 2a rotates integrally with the lever 4, the limit switch 6a is turned on only when the rotation angle of the lever 4 is within the predetermined range. Therefore, by detecting ON / OFF of the limit switch 6a, the lever 4
It is possible to detect whether or not the rotation angle of is within a predetermined range.

FIG. 3 is a block diagram of a control system of the angle detecting device shown in FIGS. 11 is a CP that controls the entire apparatus
U, and the angle detector 5 and the position detector 6 shown in FIGS. 1 and 2 are connected to the CPU 11. The CPU 11
The angle of the front attachment 3 is detected based on the angle detected by the angle detector 5 and the on / off information of the limit switch 6a inside the position detector 6. Reference numeral 12 is a ROM that stores the angle of the lever 4 when the limit switch 6a is switched from off to on. That is, since the cam surface 2a formed on the outer peripheral surface of the rotary shaft 1 rotates integrally with the lever 4, the limit switch 6a of the position detector 6 is rotated.
The true rotation angle of the lever 4 at the time of switching from OFF to ON is known in advance, and this angle is stored in the ROM 12.

FIG. 4 is a flow chart showing an example of processing executed by the CPU 11, in which the angle detected by the angle detector 5 is corrected by using the position detector 6. In step S1 of FIG. 4, the limit switch 6a of the position detector 6 is
It is determined whether is switched from off to on. If the determination is negative, the process stays at step S1, and if the determination is positive, the process proceeds to step S2. In step S2, ROM1
Read the angle stored in 2. In step S3, the angle detected by the angle detector 5 is read. In step S4, the angle detected by the angle detector 5 and the ROM 1
The amount of deviation from the angle stored in 2 is calculated, and the amount of deviation is used as a correction amount for the angle detector 5 in an EEPROM (not shown).
And so on. Next, in step S5, the angle detected by the angle detector 5 is corrected by the correction amount, and various controls (for example, trajectory control) are performed based on the corrected angle.

As described above, in the angle detecting device of the present embodiment, the cam surface 2a is provided on a part of the outer peripheral surface of the bearing 2 which rotates integrally with the lever 4, and the rotational position of the cam surface 2a is limited by the limit switch 6a. The rotation angle of the front attachment 3 can be detected accurately and quickly. Further, the angle detector 5 is compared by comparing the detection result of the limit switch 6a with the detection result of the conventional angle detector 5 including a potentiometer and detecting the deviation amount.
It is possible to accurately correct the detection result of.

Further, the position detector 6 is a limit switch 6
Since it can be configured with simple parts such as a, there is no increase in cost, and since it can be configured compactly, there is no need to worry about the installation location. Furthermore, since most of the components of the conventional angle detection device can be used, the design can be changed easily. Further, since the position detector 6 directly detects the rotational position of the lever 4, the detection error due to the variation of the mounting position, which is a problem with the conventional angle detector 5, does not occur. Further, since the position detector 6 is attached to a position where it can be easily detached from the outside, even if it is damaged, it can be easily replaced.

In the above embodiment, the detection result of the position detector 6 is used to correct the detection result of the angle detector 5. However, the detection result of the position detector 6 is used alone to work independently. May be controlled. In the above embodiment, the limit switch 6a detects the rotational position of the cam surface 2a formed on the outer peripheral surface of the bearing 2. However, the means for detecting the rotational position of the cam surface 2a is limited to the limit switch 6a. Instead, it may be detected by, for example, an optical sensor. Further, the structure of the angle detector 5 is not limited to that based on the contact resistance, and various types of angle detectors 5 can be used.

In one embodiment configured as described above, the bearing 2 serves as the bearing member, step S1 of FIG. 4 serves as the angle determination means, and the position detector 6 serves as the cam surface contact detection means.
Steps S2 to S4 of FIG. 4 correspond to the deviation amount calculating means, and step S5 of FIG. 4 corresponds to the angle correcting means.

[0017]

As described above in detail, according to the present invention, the cam surface is formed on the outer peripheral surface of the bearing member that is rotatable integrally with the lever attached to the front attachment, and the rotational position of the cam surface can be determined. Since I tried to detect
The rotation angle of the lever, that is, the angle of the front attachment can be accurately detected without using the angle detector, and is not affected by the detection error of the angle detector. According to the invention described in claim 2, at a predetermined position where the cam surface can be contacted,
Since the cam surface contact detection means for detecting the presence or absence of contact of the cam surface is provided, it is possible to easily and accurately detect whether or not the rotation angle of the lever has reached a predetermined angle. Further, since the cam surface contact detection means can be configured by a commercially available small-sized limit switch or push-button type switch, there is no increase in cost, and since it can be configured compactly, there is no problem in the installation place. Therefore, the design change from the conventional angle detection device can be easily performed. According to the invention as set forth in claim 3, the deviation amount between the detection result by the lever angle determination means and the detection result by the angle detector is calculated to correct the detection result by the angle detector. Correction can be performed easily and accurately.

[Brief description of the drawings]

FIG. 1A is a front view of an embodiment of an angle detection device according to the present invention, and FIG. 1B is a side view showing a state in which a limit switch is off.

FIG. 2A is a front view of an embodiment of the angle detection device according to the present invention, and FIG. 2B is a side view showing a state in which a limit switch is on.

FIG. 3 is a block configuration diagram of a control system of the angle detection device.

FIG. 4 is a flowchart showing an example of processing performed by a CPU.

FIG. 5A is a front view of a conventional angle detection device, and FIG.
Is a side view.

[Explanation of symbols]

 1 rotating shaft 2 bearing 2a cam surface 3 front attachment 4 lever 5 angle detector 6 position detector

Claims (3)

[Claims] 1. A lever attached to a front attachment of a working machine, a bearing member attached to one end of the lever and rotatable integrally with the lever around an axis, and an angle detector for detecting a rotation angle of the lever. In the angle detection device including a container, a cam surface is formed at a predetermined position on the outer peripheral surface of the bearing member, and whether the rotation angle of the lever is equal to or larger than a predetermined angle based on the rotation position of the cam surface. An angle detecting device comprising a lever angle determining means for determining 2. A cam surface contact detection unit is provided at a predetermined position where the cam surface can be contacted, and detects cam surface contact, and the lever angle determination unit is the cam surface contact detection unit. The angle detection device according to claim 1, wherein when the contact of the cam surface is detected by, the rotation angle of the lever is determined to be the predetermined angle. 3. A deviation amount between the rotation angle of the lever detected by the angle detector and the predetermined angle at the time when the rotation angle of the lever is determined to be the predetermined angle by the lever angle determination means. 3. A shift amount calculating means for calculating, and an angle correcting means for correcting the rotation angle of the lever detected by the angle detector based on the shift amount. Angle detection device.