Offset-boom angle detecting device

Abstract

Provided is an offset-boom angle detection device that is capable of accurately detecting an offset-boom angle.　In the present invention, a detection device 11D is attached to a work machine comprising an offset-boom mechanism 41, and detects an offset-boom angle of the offset-boom mechanism 41. The detection device 11D comprises a magnetic detection unit 111 and a magnet unit 112 which are attached to the offset-boom mechanism 41 so as to make relative rotational movement according to a change in an offset-boom angle. The magnetic detection unit 111 is disposed so as to face the magnet unit 112 in a non-contact state, and detects an offset-boom angle on the basis of a change in a magnetic field accompanying the relative rotational movement.

Description

Offset boom angle detector

[0001] The present disclosure relates to an offset boom angle detection device.

[0002] Construction machines (e.g., ICT construction machines) incorporating work support systems (e.g., machine guidance functions) have been proposed. In this type of construction machine, sensors are arranged on the moving parts, and the posture of the moving parts (e.g., bucket tip position) is detected by processing the detection results of the sensors. For example, the construction machine shown in Patent Document 1 has an IMU (INERTIAL MEASUREMENT UNIT) sensor, which includes an angular velocity sensor, an acceleration sensor, etc., arranged on the moving parts.

[0003] Japanese Patent Application Laid-Open No. 2022-101440

[0004] However, since IMU sensors have poor detection performance in the yaw direction (horizontal to the ground), when they are applied to detect the offset boom angle of construction machinery equipped with an offset boom mechanism, errors become large, making them difficult to put into practical use.

[0005] Therefore, an object of the present disclosure is to provide an offset boom angle detection device that can detect an offset boom angle with high accuracy.

[0006] In one aspect, the following solution is provided: An offset boom angle detection device that is attached to a work machine that has an offset boom mechanism and detects the offset boom angle of the offset boom mechanism, comprising a magnetic detection unit and a magnet unit that are attached to the offset boom mechanism so as to rotate relative to each other in response to changes in the offset boom angle, the magnetic detection unit being disposed to face the magnet unit in a non-contact state, and detecting the offset boom angle based on changes in a magnetic field that accompany the rotational movement.

[0007] According to the present disclosure, it is possible to provide an offset boom angle detection device that can detect the offset boom angle with high accuracy.

[0008] The offset boom angle detection device is attached to the work machine when viewed from below, and the offset boom angle detection device is attached to the work machine when viewed from below.

[0009] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0010] The work machine (construction machine) shown in Fig. 1 is a hydraulic excavator 2 equipped with a work assistance system 1. The work assistance system 1 uses, for example, a machine guidance function to assist the work of an operator operating the hydraulic excavator 2. Work machines to which the work assistance system 1 can be applied are not limited to excavators such as the hydraulic excavator 2, but may also be loading and unloading machines such as cranes.

[0011] As shown in FIG. 1 , the hydraulic excavator 2 includes an operating unit 3 , a work implement 4 , a support body 5 , and a traveling device 6 .

[0012] The work machine 4 is configured by sequentially connecting an offset boom mechanism 41, an arm 42, and a bucket 43, and is operated by an operator. The offset boom mechanism 41 is connected to the front end of the support body 5 via a boom pin 41a so as to be able to swing up and down, and swings in response to the hydraulic extension and contraction action of a boom cylinder C1 provided between the support body 5 and the offset boom mechanism 41. The arm 42 is connected to the tip of the offset boom mechanism 41 via an arm pin 42a so as to be able to swing back and forth and up and down, and swings in response to the hydraulic extension and contraction action of an arm cylinder C2 provided between the offset boom mechanism 41 and the arm 42. The bucket 43 is connected to the tip of the arm 42 via a bucket pin (attachment pin) 43a so as to be able to swing back and forth and up and down, and swings in response to the hydraulic extension and contraction action of a bucket cylinder C3 provided between the arm 42 and the bucket 43.

[0013] The bucket 43 is a type of attachment that is detachably mounted on the tip of the arm 42 and can be replaced with another attachment depending on the type of work. Examples of attachments include a grapple for gripping wood, a breaker for crushing concrete blocks, and a skeleton bucket for sieving. The work support system 1 is not limited to excavation work using the bucket 43, but can also be applied to work using other attachments.

[0014] The offset boom mechanism 41 includes a first boom 411, a second boom 412, a third boom 413, and a link member (not shown). The first boom 411 is supported on the support body 5 via a boom pin 41a so as to be able to swing up and down. The second boom 412 is supported at the tip of the first boom 411 via a first offset pin (not shown) so as to be able to swing left and right. The third boom 413 is supported at the tip of the second boom 412 via a second offset pin 413a (see FIGS. 2 and 3) so as to be able to swing left and right, and supports the arm 42 via an arm pin 42a so as to be able to swing back and forth and up and down. The link member is disposed parallel to the second boom 412 and is supported by the first boom 411 and the third boom 413 so as to be able to swing left and right.

[0015] The first boom 411, second boom 412, third boom 413 and link member constitute a parallel link mechanism that offsets (translates) the third boom 413, arm 42 and bucket 43 left and right in response to the left and right swing of the second boom 412. The offset boom mechanism 41 also includes an offset cylinder (not shown) between the first boom 411 and second boom 412, and is offset left and right in response to the hydraulic extension and retraction of the offset cylinder.

[0016] The operation unit 3 is a riding space for an operator who operates the hydraulic excavator 2. The support body 5 supports the operation unit 3 and the work machine 4. The traveling device 6 supports the support body 5 so that it can turn and travel. The traveling device 6 is not limited to a crawler type having crawlers 61 as shown in FIG. 1 , but may also be a wheel type having wheels (not shown).

[0017] As shown in FIGS. 1 to 3, the work support system 1 includes a plurality of detection devices 11A to 11D, a collection device 12, and a mobile terminal 13.

[0018] 1 , the detection devices 11A, 11B, and 11C are respectively installed on the first boom 411, the arm 42, and the bucket 43, detect the attitude of the installation location, and wirelessly transmit the detected attitude information to the collection device 12. For example, the detection devices 11A, 11B, and 11C are equipped with IMU sensors that detect three-dimensional acceleration and angular velocity, and transmit the attitude information of the installation location detected by the IMU sensors to the collection device 12 using a wireless communication method such as BLUETOOTH (registered trademark) LOW ENERGY communication.

[0019] The detection devices 11A, 11B, and 11C each have a built-in battery (not shown) and operate on power supplied from the battery. Such detection devices 11A, 11B, and 11C can be easily installed in a desired mounting location without the need to take the trouble of routing a power supply cable or a data communication cable to the work machine 4. As a result, the work assistance system 1 of this embodiment can easily add machine guidance functions to an existing work machine or update the machine guidance functions.

[0020] The detection devices 11A, 11B, and 11C also include magnetically attached portions (not shown). The magnetically attached portions are, for example, permanent magnets, and the magnetic force of the magnetically attached portions secures the detection devices 11A, 11B, and 11C to the first boom 411, the arm 42, and the bucket 43, each of which is made of metal. Such detection devices 11A, 11B, and 11C can be more easily installed at desired locations.

[0021] The detection device 11D is installed in the offset boom mechanism 41, detects the offset boom angle of the offset boom mechanism 41 (the left and right swing angle of the second boom 412), and wirelessly transmits the detected information to the collection device 12. Details of the detection device 11D will be described later.

[0022] The collecting device 12 is installed on the support body 5, detects the attitude of the support body 5, and receives the attitude information of the work machine 4 transmitted by the detecting devices 11A to 11D. The collecting device 12 then wirelessly transmits the attitude information of the work machine 4 and the support body 5 to the mobile terminal 13.

[0023] The mobile terminal 13 is a so-called smartphone or tablet terminal, and functions as a machine guidance terminal by executing application software (dedicated app) related to the work support system 1. For example, the mobile terminal 13 calculates the distance between the bucket 43 and the target construction surface based on the multiple pieces of attitude information received from the collection device 12, and displays the calculated distance on the display unit 13a of the mobile terminal 13.

[0024] Next, the detection device 11D, which is a main part of the present invention, will be described with reference to FIGS.

[0025] The detector 11D includes a magnetic detection unit 111 and a magnet unit 112 attached to the offset boom mechanism 41 so as to rotate relative to each other in response to changes in the offset boom angle. The magnet unit 112 includes a permanent magnet and generates a magnetic field around it. The magnetic detection unit 111 includes a magnetic detection element (e.g., a Hall IC) that detects magnetism and outputs changes in the magnetic field as changes in voltage.

[0026] The magnetic detection unit 111 is disposed opposite the magnet unit 112 in a non-contact state, and detects changes in the magnetic field that accompany relative rotational movement with respect to the magnet unit 112. This makes it possible to detect the offset boom angle of the offset boom mechanism 41 based on the output voltage of the magnetic detection unit 111.

[0027] Such a detection device 11D does not produce large errors in the yaw direction as an IMU sensor does, and can therefore accurately detect the offset boom angle of the offset boom mechanism 41. Furthermore, the detection device 11D detects the offset boom angle using the magnetic detection unit 111 and magnet unit 112, which are arranged in a non-contact state and rotate relative to each other in response to changes in the offset boom angle, and therefore can achieve improved durability compared to when a contact-type angle sensor is used.

[0028] The offset boom angle to be detected by the detection device 11D is the relative left / right swing angle between the first boom 411 and the second boom 412, or the relative left / right swing angle between the second boom 412 and the third boom 413.

[0029] The magnetic detection unit 111 is attached to any one of the first boom 411 , the second boom 412 and the third boom 413 .

[0030] When the magnetic detection unit 111 is attached to the tip side of the first boom 411, the magnet unit 112 is attached to the base end side of the second boom 412 so as to face the magnetic detection unit 111 in a non-contact state.

[0031] Furthermore, when the magnetic detection unit 111 is attached to the base end side of the second boom 412, the magnet unit 112 is attached to the tip side of the first boom 411 so as to face the magnetic detection unit 111 in a non-contact state.

[0032] Furthermore, when the magnetic detection unit 111 is attached to the tip side of the second boom 412, the magnet unit 112 is attached to the base end side of the third boom 413 so as to face the magnetic detection unit 111 in a non-contact state.

[0033] Furthermore, when the magnetic detection unit 111 is attached to the base end side of the third boom 413, the magnet unit 112 is attached to the tip side of the second boom 412 so as to face the magnetic detection unit 111 in a non-contact manner. The detection device 11D will be described in more detail below with reference to Figures 2 and 3 which show this attachment example.

[0034] The magnetic detection unit 111 and the magnet unit 112 are attached to the offset boom mechanism 41 via attachment stays 113 and 114, respectively.

[0035] In the mounting example shown in Figures 2 and 3, the appropriate position for the magnetic detection unit 111 is on the rotation axis of the second offset pin 413a. Therefore, the mounting stay 113 includes multiple fixing portions 113a, a stay main body 113b, and a mounting portion 113c. The multiple fixing portions 113a are fixed to the underside of the third boom 413. The stay main body 113b has a generally inverted U shape and is connected to the multiple fixing portions 113a so as to straddle the end faces of the second offset pins 413a. The mounting portion 113c extends from the center of the stay main body 113b in the direction of the rotation axis of the second offset pin 413a, and the magnetic detection unit 111 is mounted to the mounting portion 113c. This allows the magnetic detection unit 111 to be easily mounted in the appropriate position.

[0036] In the mounting example shown in FIGS. 2 and 3 , the proper position for the magnet unit 112 is a position along the rotation axis of the second offset pin 413a, facing the magnetic detection unit 111 without contact. Therefore, the mounting stay 114 includes multiple fixing portions 114a, a stay body 114b, and a mounting portion 114c. The multiple fixing portions 114a are fixed to the underside of the second boom 412. The stay body 114b has a generally inverted L-shape and extends from the multiple fixing portions 114a toward the rotation axis of the second offset pin 413a. The mounting portion 114c extends from the tip of the stay body 114b in the direction of the rotation axis of the second offset pin 413a, and the magnet unit 112 is mounted to the mounting portion 114c. This allows the magnet unit 112 to be mounted in the proper position.

[0037] The fixing portions 113a, 114a of the mounting stays 113, 114 preferably include magnetically attached portions 113d, 114d. The magnetically attached portions 113d, 114d are, for example, permanent magnets, and are fixed to the third boom 413 and the second boom 412, which are made of metal, by their magnetic force. With such mounting stays 113, 114, the magnetic detection unit 111 and the magnet unit 112 can be easily installed in appropriate positions.

[0038] The detection device 11D further includes a transmission unit 115 that wirelessly transmits the offset boom angle (voltage value) detected by the magnetic detection unit 111 to the collection device 12. The transmission unit 115 has a built-in wireless communication module and battery (not shown), and is connected to the magnetic detection unit 111 via a cable 116. The magnetic detection unit 111 operates using power supplied from the transmission unit 115 and outputs the detected offset boom angle to the transmission unit 115. The transmission unit 115 transmits the offset boom angle input from the magnetic detection unit 111 to the collection device 12 via BLE communication. Such a detection device 11D can be easily installed at a desired mounting location without the need to bother running a power supply cable or a data communication cable to the work machine 4.

[0039] The transmitting unit 115 includes a magnetically attached portion 115a, which is, for example, a permanent magnet, and is fixed by its magnetic force to the second boom 412 made of metal or to a metal plate 117 provided on the second boom 412. Using these mounting stays 113, 114, the magnetic detection unit 111 and the magnet unit 112 can be easily installed in appropriate positions.

[0040] Although each embodiment has been described in detail above, it is not limited to the specific embodiment, and various modifications and changes are possible within the scope of the claims. It is also possible to combine all or a plurality of components of the above-described embodiments.

[0041] 1 Work support system 2 Hydraulic excavator (work machine) 3 Operation unit 4 Work machine 41 Offset boom mechanism 41a Boom pin 411 First boom 412 Second boom 413 Third boom 413a Second offset pin 42 Arm 42a Arm pin 43 Bucket 43a Bucket pin 5 Support body 6 Traveling device 11A to 11C Detector 11D Detector (offset boom angle detector) 111 Magnetic detection unit 112 Magnet unit 113 Mounting stay 113a Fixed portion 113b Stay body 113c Mounting portion 113d Magnetic portion 114 Mounting stay 114a Fixed portion 114b Stay body 114c Mounting portion 114d Magnetic portion 115 Transmission unit 115a Magnetic portion 116 Cable 12 Collection device 13 Mobile terminal

Claims

1. An offset boom angle detection device that is attached to a work machine equipped with an offset boom mechanism and detects the offset boom angle of the offset boom mechanism, comprising a magnetic detection unit and a magnet unit that are attached to the offset boom mechanism so as to undergo relative rotational movement in response to changes in the offset boom angle, the magnetic detection unit is positioned opposite the magnet unit in a non-contact state, and detects the offset boom angle based on changes in a magnetic field associated with the rotational movement.

2. The offset boom angle detection device according to claim 1, wherein the offset boom mechanism comprises: a first boom supported on the main body of the work machine so as to be swingable up and down; a second boom supported on the tip of the first boom so as to be swingable left and right; and a third boom supported on the tip of the second boom so as to be swingable left and right; the offset boom angle to be detected is the relative left and right swing angle between the first boom and the second boom, or the relative left and right swing angle between the second boom and the third boom; the magnetic detection unit is attached to any of the first boom, the second boom, and the third boom; when the magnetic detection unit is attached to the first boom, the magnet unit is attached to the second boom so as to face the magnetic detection unit in a non-contact state; when the magnetic detection unit is attached to the second boom, the magnet unit is attached to the first boom or the third boom so as to face the magnetic detection unit in a non-contact state; and when the magnetic detection unit is attached to the third boom, the magnet unit is attached to the second boom so as to face the magnetic detection unit in a non-contact state.

3. An offset boom angle detection device as described in claim 1, wherein the magnetic detection unit and the magnet unit are each attached to the offset boom mechanism via a mounting stay, and the mounting stay has a magnetic portion that is fixed to the offset boom mechanism by magnetic force.

4. An offset boom angle detection device as set forth in claim 1, further comprising a transmission unit capable of wirelessly transmitting the offset boom angle detected by the magnetic detection unit.

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