Construction machinery

Abstract

To provide construction equipment capable of measuring a tension amount of a crawler, even in a short work period and narrow work space, and preventing damage to a distance sensor due to sand and rock.SOLUTION: On a lower travel body 2, an upper turning body 4 is provided so as to freely turn. On a turning frame 17 as a bottom of the upper turning body 4, a distance sensor 18 for measuring a distance from a crawler 11 as a tension amount (loosening amount) of the crawler 11, is provided. Therefore, the distance sensor 18 is provided on the turning frame 17 at a higher position higher than the crawler 11 of the lower travel body 2. The distance sensor 18 can measure the distance to a top face side of the crawler 11 in a state in which the crawler 11 is on a ground surface.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a construction machine provided with a lower traveling body that travels by circulating a crawler.

Background Art

[0002] A hydraulic excavator, which is a representative example of a construction machine, includes a self-propelled crawler-type lower traveling body, an upper revolving body rotatably provided on the lower traveling body, and a working device rotatably provided at the front of the upper revolving body.

[0003] The lower traveling body includes a track frame provided with track side frames extending in the front-rear direction on both the left and right sides, a drive wheel provided at the rear end, which is one end in the longitudinal direction of the track side frame, a idler wheel provided at the front end, which is the other end in the longitudinal direction of the track side frame, and a crawler wound around the drive wheel and the idler wheel. Further, the lower traveling body includes an upper roller that supports the crawler from below on the upper part of the track side frame.

[0004] In a crawler-type lower traveling body, the idler wheel is provided so as to be movable in the front-rear direction with respect to the track side frame. Further, between the idler wheel and the track side frame, a crawler tensioning device is provided that adjusts the tension of the crawler by the amount of grease injected into an adjuster cylinder. Thereby, the lower traveling body measures the tension (slack amount) of the crawler, and adjusts the amount of grease injected into the adjuster cylinder of the crawler tensioning device based on the measurement result, so that an appropriate load acts on the drive wheel, idler wheel, upper roller, crawler, etc., and the tension of the crawler can be adjusted.

[0005] Here, when measuring the tension of the crawler, the upper revolving body is rotated 90 degrees with respect to the lower traveling body, and the working device is pressed against the ground to lift one crawler. In this state, the distance from the track side frame to the crawler is measured as the tension (slack amount) of the crawler.

[0006] Therefore, a hydraulic excavator is known to have a configuration in which a distance sensor is installed on the lower part of the track side frame, and this distance sensor measures the distance from the track side frame to the track (Patent Document 1). [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Japanese Patent Application Publication No. 7-108961 [Overview of the project] [Problems that the invention aims to solve]

[0008] In the hydraulic excavator described in Patent Document 1, the distance sensor is located on the underside of the track side frame. Therefore, when measuring the track tension, the work device must be pressed against the ground and the track lifted. Consequently, measuring the track tension requires a significant amount of work time to operate the work device and a large workspace that allows the work device to rotate with its extension extended. Moreover, the underside of the track side frame where the distance sensor is located is prone to contact with soil and rocks during travel and operation, so there is a risk that the distance sensor may be damaged by soil and rocks.

[0009] This invention has been made in view of the problems of the prior art described above, and the object of this invention is to provide a construction machine that can measure the tension of the track even with a short working time and in a narrow working space, and that can prevent damage to the distance sensor from soil and rocks. [Means for solving the problem]

[0010] The present invention relates to a construction machine comprising a self-propelled lower traveling body and an upper rotating body rotatably mounted on the lower traveling body, wherein the lower traveling body comprises a track frame with track side frames extending in the front-rear direction on both the left and right sides, a drive wheel provided at one end of the track side frame in the longitudinal direction, a idler wheel provided at the other end of the track side frame in the longitudinal direction, a track belt wound around the drive wheel and the idler wheel, and an upper roller provided on the upper part of the track side frame to support the track belt from below, wherein a distance sensor for measuring the distance to the track belt is provided at the bottom of the upper rotating body. The distance sensor is positioned so that when the upper rotating body rotates, it passes through at least one of the following locations: near the midpoint between the drive wheel and the upper roller, or near the midpoint between the idler wheel and the upper roller. It is. Furthermore, the present invention relates to a construction machine comprising a self-propelled lower traveling body and an upper rotating body rotatably mounted on the lower traveling body, wherein the lower traveling body comprises a track frame with track side frames extending in the front-rear direction on both the left and right sides, a drive wheel provided at one end of the track side frame in the longitudinal direction, a freewheel provided at the other end of the track side frame in the longitudinal direction, a track belt wound around the drive wheel and the freewheel, and an upper roller provided on the upper part of the track side frame and supporting the track belt from below, wherein a distance sensor for measuring the distance to the track belt is provided at the bottom of the upper rotating body, and the distance sensor is positioned so as to be able to measure the distance to the track belt at one or both of three locations: above the drive wheel, above the upper roller, and above the midpoint between the drive wheel and the upper roller, or above the freewheel, above the upper roller, and above the midpoint between the freewheel and the upper roller. Furthermore, the present invention relates to a construction machine comprising a self-propelled lower traveling body and an upper rotating body rotatably mounted on the lower traveling body, wherein the lower traveling body comprises a track frame with track side frames extending in the front-rear direction on both the left and right sides, a drive wheel provided at one end of the track side frame in the longitudinal direction, a freewheel provided at the other end of the track side frame in the longitudinal direction, a track belt wound around the drive wheel and the freewheel, and an upper roller provided on the upper part of the track side frame and supporting the track belt from below, wherein a distance sensor for measuring the distance to the track belt is provided at the bottom of the upper rotating body, the distance sensor is mounted so as to be movable in the front-rear direction relative to the upper rotating body, and is provided so as to be movable for a distance corresponding to the range from the drive wheel to the upper roller or the range from the freewheel to the upper roller. [Effects of the Invention]

[0011] According to the present invention, the tension of the track can be measured even with a short working time and in a narrow working space, and damage to the distance sensor by soil and rocks can be prevented. [Brief explanation of the drawing]

[0012] [Figure 1] This is a left side view showing a hydraulic excavator applied to the first embodiment of the present invention. [Figure 2] This is a left side view showing the rear portion of a hydraulic excavator. [Figure 3] This is a plan view showing the lower running gear with the tracks omitted. [Figure 4] This is a plan view showing the swivel frame and distance sensor. [Figure 5] This is a plan view showing the positional relationship between the distance sensors of the lower traveling body and the upper rotating body. [Figure 6] This is a plan view similar to Figure 5, showing the upper rotating body rotated so that the distance sensor is positioned at the location for measuring the track tension. [Figure 7] This is a left side view showing a distance sensor (mobile sensor device) according to a second embodiment of the present invention together with the rear portion of a hydraulic excavator. [Figure 8] It is a plan view showing a swing frame and a distance sensor (mobile sensor device). [Figure 9] It is a plan view showing a state in which the upper swing body is swung so that the distance sensor is arranged at the upper part of the drive wheel, the upper part of the upper roller, and the measurement position of the tension of the crawler belt. [Figure 10] It is a left side view showing three distance sensors according to a modified example of the present invention together with the rear side portion of the hydraulic excavator. [Figure 11] It is a plan view showing the positional relationship between the three distance sensors of the lower traveling body and the upper swing body.

Mode for Carrying Out the Invention

[0013] Hereinafter, as a representative example of a construction machine according to an embodiment of the present invention, a hydraulic excavator equipped with a track-mounted lower traveling body will be taken as an example and described in detail with reference to the accompanying drawings. In the present embodiment, for the upper swing body, the side where the working device is provided is the front side, the side where the counterweight is provided is the rear side, and for the lower traveling body, the side where the idler wheel is provided is the front side and the side where the drive wheel is provided is the rear side for explanation.

[0014] Figs. 1 to 6 show a first embodiment of the present invention. In Fig. 1, a track-mounted hydraulic excavator 1 includes a self-propelled lower traveling body 2, an upper swing body 4 mounted on the lower traveling body 2 so as to be swingable via a swing device 3, and a working device 5 provided rotatably at the front of the upper swing body 4 for performing earth and sand excavation work and the like. The swing device 3 is a mechanism for swinging the upper swing body 4 on the lower traveling body 2. The swing device 3 includes a swing ring 3A composed of an annular bearing provided between the track frame 6 of the lower traveling body 2 and the swing frame 17 of the upper swing body 4, and a swing motor (not shown) that meshes with the inner ring of the swing ring 3A to swing the upper swing body 4. The state in which the front and rear of the upper swing body 4 and the front and rear of the lower traveling body 2 are aligned as shown in Fig. 1 is referred to as the basic position.

[0015] The crawler-type lower traveling body 2 is for traveling on uneven ground, muddy ground, etc. As shown in FIGS. 1 to 3, the lower traveling body 2 includes a track frame 6, drive wheels 9, idler wheels 10, crawler belts 11, upper rollers 12, and lower rollers 13, which will be described later.

[0016] The track frame 6 includes a track center frame 7 located at the center in the left-right direction (width direction of the lower traveling body 2) and track side frames 8 provided on both the left and right sides of the track center frame 7.

[0017] The track center frame 7 is formed as a can-making structure of X shape or H shape as a whole by welding a plurality of steel plates. The track center frame 7 has a cylindrical portion 7A protruding upward at the center, and a swivel wheel 3A of the swivel device 3 is attached on this cylindrical portion 7A. The centers of the cylindrical portion 7A and the swivel wheel 3A become the swivel center O of the upper swivel body 4 (see FIGS. 3, 4, etc.).

[0018] The track side frames 8 are provided on both the left and right sides of the track center frame 7 and extend in the front-rear direction. The track side frames 8 are arranged symmetrically on both the left and right sides of the track center frame 7. The track side frames 8 are formed as angular cylindrical bodies extending in the front-rear direction. A drive wheel bracket 8A is provided at the rear end, which is one end in the length direction of the track side frame 8. On the other hand, an idler wheel bracket 8B is provided at the front end, which is the other end in the length direction of the track side frame 8. Also, two upper rollers 12 are provided on the upper part of the track side frame 8 at intervals in the front-rear direction.

[0019] The drive wheels 9 are provided on a drive wheel bracket 8A located at the rear end, which is one end in the length direction of the track side frame 8. The drive wheels 9 include a reduction gear 9A attached to the drive wheel bracket 8A, a traveling motor (not shown) connected to the input side of the reduction gear 9A, and a sprocket 9B provided on the output side of the reduction gear 9A. The outer peripheral side of the sprocket 9B meshes with the crawler belt 11.

[0020] The idler wheel 10 is mounted on the idler wheel bracket 8B, which is located at the front end of the track side frame 8, the other end in the longitudinal direction. The idler wheel 10 is mounted so as to be movable in the front-rear direction relative to the idler wheel bracket 8B. A track tensioning device (not shown) consisting of a coil spring, an adjuster cylinder, etc., is provided between the idler wheel 10 and the track side frame 8. This track tensioning device can adjust the tension of the track by adjusting the amount of grease injected into the adjuster cylinder.

[0021] The track 11 is wrapped around the drive wheel 9 and the idler wheel 10. For example, the track 11 is composed of a large number of track links connected in the circumferential direction and a large number of track shoes attached to each track link. Here, even if slight wear occurs in the connecting parts between the track links, for example, the wear of the large number of track links will combine to stretch and cause slack. Also, wear that occurs between the track 11 and the sprocket 9B of the drive wheel 9, the idler wheel 10, the upper roller 12, and the lower roller 13 will also cause the track 11 to slacken. When the track 11 slackens in this way, it may become difficult to switch between forward and reverse, the running noise may increase, and vibrations may occur, so it is desirable to periodically adjust the tension (slack) of the track 11.

[0022] The upper rollers 12 are located on the upper part of the track side frame 8. The upper rollers 12 support the track 11 from below. For example, two upper rollers 12 are provided spaced apart in the front-rear direction.

[0023] As shown in Figures 1 and 2, the lower rollers 13 are located at the bottom of the track side frame 8. The lower rollers 13 press the track 11 against the ground from above. Multiple lower rollers 13 are provided, for example, seven of them, spaced apart in the front-rear direction.

[0024] Next, the configuration of the upper slewing body 4 will be described. As shown in Figure 1, the upper slewing body 4 comprises a slewing frame 17 (described later), a cab 14 mounted on the left front side of the slewing frame 17 and forming a driver's cabin inside, a counterweight 15 attached to the rear of the slewing frame 17 to balance the weight with the work equipment 5, and a building 16 located between the cab 14 and the counterweight 15 that houses the engine, hydraulic pump (neither shown), etc. mounted on the slewing frame 17. Inside the cab 14, there is a driver's seat where the operator sits, and driving and working control levers (neither shown) located in front of, to the left of, and to the right of the driver's seat to operate the hydraulic excavator 1.

[0025] The slewing frame 17 forms the bottom of the upper slewing body 4. As shown in Figure 4, the slewing frame 17 is composed of a flat bottom plate 17A made of a thick steel plate or the like that extends in the front-rear direction, a left vertical plate 17B and a right vertical plate 17C erected on the bottom plate 17A and extending in the front-rear direction at predetermined intervals in the left-right direction, a plurality of left overhang beams 17D extending to the left from the bottom plate 17A and the left vertical plate 17B at intervals in the front-rear direction, a plurality of right overhang beams 17E extending to the right from the bottom plate 17A and the right vertical plate 17C at intervals in the front-rear direction, a left side frame 17F attached to the tip of the left overhang beam 17D in a state extending in the front-rear direction, and a right side frame 17G attached to the tip of the right overhang beam 17E in a state extending in the front-rear direction.

[0026] Furthermore, the swivel frame 17 is equipped with multiple undercovers 17H that cover the space between the bottom plate 17A, the left vertical plate 17B, and the right vertical plate 17C (only the space between the left vertical plate 17B and the right vertical plate 17C on the rear side of the bottom plate 17A is shown). In addition, the bottom plate 17A has a joint insertion hole 17J through which a center joint (not shown) is inserted. The center of the joint insertion hole 17J is the pivot center O of the upper swivel body 4.

[0027] For example, the left side frame 17F and the right side frame 17G are formed from pipe members. The left side frame 17F is located above the left track 11 when the working device 5 is positioned in front of the lower running body 2. Similarly, the right side frame 17G is located above the right track 11 when the working device 5 is positioned in front of the lower running body 2.

[0028] The distance sensor 18 is installed on the slewing frame 17 that forms the bottom of the upper slewing body 4. The distance sensor 18 measures the distance S1 from the distance sensor 18 to the track 11. As shown in Figure 4, the distance sensor 18 is installed near the rear of the left side frame 17F of the slewing frame 17. For the distance sensor 18, a non-contact type sensor using, for example, infrared, laser, or ultrasonic waves is used. In sites where dust and soil are scattered, a distance sensor using ultrasonic waves, which are less affected by dust and soil, is suitable. The distance sensor 18 may have, for example, a cylindrical appearance and be screwed in while being inserted vertically into an insertion hole formed in the lower part of the left side frame 17F.

[0029] The mounting position of the distance sensor 18 on the upper rotating body 4 will now be described. The distance sensor 18 is positioned so that when the upper rotating body 4 rotates on the lower traveling body 2, it passes through the midpoint of at least one of the following locations: the midpoint between the drive wheel 9 and the rear upper roller 12, and the midpoint between the idler wheel 10 and the front upper roller 12.

[0030] Here, as shown in Figure 2, if we define line A (shown as center point A in the plan view of Figure 3) as a straight line extending vertically through the center of the sprocket 9B of the drive wheel 9 located on the left track side frame 8C, and line B (shown as center point B in the plan view of Figure 3) as a straight line extending vertically through the center of the left rear upper roller 12, then the position where the left track 11 sags significantly between the drive wheel 9 and the rear upper roller 12 is approximately midway between the drive wheel 9 and the rear upper roller 12, specifically at the midpoint C between the drive wheel 9 and the rear upper roller 12 (shown as line C extending vertically through midpoint C in the left side view of Figure 2). More specifically, if the distance between line A and line B is dimension L, then the distance between line A and midpoint C (line C) is dimension L / 2. Similarly, the distance between line B and midpoint C (line C) is dimension L / 2.

[0031] As shown in Figure 3, the midpoint C (line C) is located on the arc Q1 drawn with radius R1 from the pivot center O. Furthermore, as shown in Figure 4, the distance sensor 18 is positioned on the left side frame 17F at a location that passes through the arc Q1. As a result, as shown in Figure 5, the midpoint C (line C) where the track 11 sags significantly between the drive wheel 9 and the rear upper roller 12, and the distance sensor 18 are located on the arc Q1.

[0032] Specifically, as shown by the dashed line P1 in Figure 6, the distance sensor 18 can be positioned directly above the midpoint C when the upper rotating body 4 is rotated approximately 5 degrees counterclockwise in a plan view from the basic position P0 in Figure 5. In this state, the distance S1 between the distance sensor 18 and the left track 11 is measured by the distance sensor 18. This makes it possible to measure the tension (slack) of the track 11 based on the distance S1 at the position where the left track 11 slackens significantly, approximately midway between the drive wheel 9 and the rear upper roller 12.

[0033] Furthermore, as shown in Figure 3, if we define line D (shown as center point D) as a straight line extending vertically through the center of the idler wheel 10 on the left track side frame 8C, and line E (shown as center point E) as a straight line extending vertically through the center of the left front upper roller 12, then the position where the left track 11 sags significantly, near the midpoint between the idler wheel 10 and the front upper roller 12, is the midpoint F between the idler wheel 10 and the front upper roller 12. The midpoint F between the idler wheel 10 and the front upper roller 12 is on or close to the arc Q1. As a result, the midpoint F where the left track 11 sags significantly, near the midpoint between the idler wheel 10 and the front upper roller 12, is located on the same arc Q1 as the distance sensor 18.

[0034] Specifically, as shown by the dashed line P2 in Figure 6, when the upper rotating body 4 is rotated approximately 80 degrees clockwise in a plan view, the distance sensor 18 can be positioned directly above the midpoint F. In this state, the distance sensor 18 measures the distance between the distance sensor 18 and the left track 11. This allows the tension (slack) of the track 11 to be measured at the point where the left track 11 slackens significantly, approximately midway between the idler wheel 10 and the front upper roller 12.

[0035] On the other hand, a straight line extending vertically through the center of the drive wheel 9 located on the right track side frame 8D is defined as line G (illustrated as center point G), and a straight line extending vertically through the center of the right rear upper roller 12 is defined as line H (illustrated as center point H). In this case, the position where the right track 11 sags significantly, near the midpoint between the drive wheel 9 and the rear upper roller 12, is the midpoint J between the drive wheel 9 and the rear upper roller 12. The midpoint J between the drive wheel 9 and the rear upper roller 12 is on or close to the arc Q1. As a result, the midpoint J where the right track 11 sags significantly, near the midpoint between the drive wheel 9 and the rear upper roller 12, is located on the same arc Q1 as the distance sensor 18.

[0036] In other words, by rotating the upper rotating body 4, the distance sensor 18 can be positioned directly above the midpoint J. In this state, the distance sensor 18 measures the distance between the distance sensor 18 and the right track 11. This makes it possible to measure the tension (slack) of the track 11 at the point where the right track 11 slackens significantly, approximately midway between the drive wheel 9 and the rear upper roller 12.

[0037] Furthermore, a straight line extending vertically through the center of the idler wheel 10 on the right track side frame 8D is defined as line K (illustrated as center point K), and a straight line extending vertically through the center of the right front upper roller 12 is defined as line M (illustrated as center point M). In this case, the position where the right track 11 sags significantly, near the midpoint between the idler wheel 10 and the front upper roller 12, is the midpoint N between the idler wheel 10 and the front upper roller 12. The midpoint N between the idler wheel 10 and the front upper roller 12 is on or close to the arc Q1. As a result, the midpoint N where the right track 11 sags significantly, near the midpoint between the idler wheel 10 and the front upper roller 12, is located on the same arc Q1 as the distance sensor 18.

[0038] In other words, by rotating the upper rotating body 4, the distance sensor 18 can be positioned directly above the midpoint N. In this state, the distance sensor 18 measures the distance between the distance sensor 18 and the right track 11. This makes it possible to measure the tension (slack) of the track 11 at the point where the right track 11 slackens significantly, approximately midway between the idler wheel 10 and the front upper roller 12.

[0039] In this first embodiment, the distance to the track 11 wrapped around the left track side frame 8C is measured at two points, midpoint C and midpoint F, by the distance sensor 18, and the distance to the track 11 wrapped around the right track side frame 8D is measured at two points, midpoint J and midpoint N, for a total of four points where the amount of slack in the track 11 is measured. Alternatively, the distance to one midpoint may be measured for the track 11 on the left track side frame 8C, and the distance to one midpoint may be measured for the track 11 on the right track side frame 8D.

[0040] Next, we will describe an example of the procedure for measuring the tension (slack) of the left and right tracks 11 using the distance sensor 18 installed on the left side frame 17F of the slewing frame 17 of the upper slewing body 4.

[0041] When measuring the tension (slack) of the track 11, accurate measurements can be obtained by maintaining a consistent measurement environment. First, the hydraulic excavator 1 is positioned on a flat surface suitable for measuring the tension of the track 11. The space required in this case is the space necessary for the upper rotating body 4 to rotate with the working device 5 raised and the entire working device 5 folded. In other words, by securing space for the upper rotating body 4 to rotate, the tension of the track 11 can be measured. Also, as a preparatory step before measuring the tension of the track 11, the hydraulic excavator 1 (lower traveling body 2) is slowly moved forward and stopped in order to keep the condition of the track 11 constant.

[0042] After stopping the hydraulic excavator 1, the work device 5 is raised and then folded up. Next, with the tension measurement switch for the track 11 turned ON, the upper rotating body 4 is rotated 360 degrees. At this time, the controller (not shown) mounted on the hydraulic excavator 1 extracts the distance S1 from the distance sensor 18 to the track 11 when the distance sensor 18 is positioned on the midpoint C, based on the rotation angle of the upper rotating body 4 relative to the lower running body 2. Similarly, the distance from the distance sensor 18 to the track 11 is extracted when it is positioned on the midpoints F, J, and N.

[0043] This allows the tension of the track 11, including the distance S1 from the distance sensor 18 to the left track 11, to be compared with a dimension set as a threshold. If the measured tension of the track 11 exceeds the threshold, the tension of the track 11 is adjusted.

[0044] The hydraulic excavator 1 according to this embodiment has the configuration described above, and its operation will now be explained.

[0045] The operator boards the cab 14, sits in the driver's seat, starts the engine, and operates the drive levers to move the lower vehicle 2. Meanwhile, the operator can operate the work levers to rotate the upper slewing body 4 and perform earth excavation work with the work device 5.

[0046] The tracks 11 of the hydraulic excavator 1 will slacken (relative stretch) if wear occurs in areas such as the connecting parts between track links, the sprocket 9B between the track 11 and the drive wheel 9, the idler wheel 10, the upper roller 12, and the lower roller 13. Therefore, the hydraulic excavator 1 undergoes periodic measurement and adjustment of the track tension 11. The track tension adjustment can be increased and the slack of the track 11 reduced by injecting grease into the adjuster cylinder of the track tensioning device located between the idler wheel 10 and the track side frame 8.

[0047] Thus, according to this embodiment, the slewing frame 17, which serves as the bottom of the upper slewing body 4 that is rotatably mounted on the lower running body 2, is equipped with a distance sensor 18 that measures the distance to the track 11 as the tension (slack) of the track 11. Therefore, the distance sensor 18 is mounted on the slewing frame 17 at a position higher than the track 11 of the lower running body 2. In this configuration, the distance sensor 18 measures the distance to the upper surface of the track 11.

[0048] As a result, in this embodiment, the tension (slack) of the track 11 can be measured without lifting the track 11. Consequently, the tension of the track 11 can be easily measured even with limited working time and in a confined workspace.

[0049] Furthermore, since the distance sensor 18 is located on the swivel frame 17, which is higher than the lower traveling body 2, even if soil or rocks are kicked up during travel or work, it is less likely that the soil or rocks will collide with the distance sensor 18. This prevents damage to the distance sensor 18 from soil or rocks, improving its durability and reliability.

[0050] The distance sensor 18 is positioned to pass through both the midpoint between the drive wheel 9 and the rear upper roller 12, and the midpoint between the idler wheel 10 and the front upper roller 12, when the upper rotating body 4 rotates on the lower running body 2. Therefore, by simply rotating the upper rotating body 4 once on the lower running body 2, the tension of the left track 11 can be measured at midpoints C and J between the drive wheel 9 and the rear upper roller 12, and the tension of the right track 11 can be measured at midpoints F and N between the idler wheel 10 and the front upper roller 12. This allows for tension to be measured at two points for each track 11, thereby improving the reliability of the measured values.

[0051] Furthermore, the midpoints C and J between the drive wheel 9 and the rear upper roller 12, and the midpoints F and N between the idler wheel 10 and the front upper roller 12, are the points where the slack in the track 11 is greatest, so the amount of slack in the track 11 can be clearly measured.

[0052] Next, Figures 7 to 9 show a second embodiment of the present invention. A feature of this embodiment is that the distance sensor is positioned to measure the distance to the track at three locations: above the drive wheel, above the upper roller, and above the midpoint between the drive wheel and the upper roller, and also at three locations: above the idler wheel, above the upper roller, and above the midpoint between the idler wheel and the upper roller. Furthermore, the distance sensor is movably mounted on the upper rotating body. Specifically, the distance sensor is provided to move at distances corresponding to the range from the drive wheel to the upper roller or from the idler wheel to the upper roller. In the second embodiment, the same reference numerals are used for the same components as in the first embodiment described above, and their descriptions are omitted.

[0053] In Figure 7, the movable distance sensor 21, which functions as a distance sensor, is mounted on the slewing frame 17 of the upper slewing body 4. As shown in Figure 8, the movable distance sensor 21 is located on the rear side of the slewing frame 17 and is attached to the under cover 17H between the left vertical plate 17B and the right vertical plate 17C. The movable distance sensor 21 is mounted so as to be movable in the front-rear direction relative to the upper slewing body 4. Specifically, the movable distance sensor 21 includes a sensor body 21B that can move a distance corresponding to the range from the drive wheel 9 to the rear upper roller 12 or from the idler wheel 10 to the front upper roller 12.

[0054] For example, the mobile distance sensor 21 includes a long, box-shaped casing 21A extending in the front-to-back direction and attached to the under cover 17H, a sensor body 21B provided to be movable in the front-to-back direction along the casing 21A, and a moving mechanism 21C for moving the sensor body 21B to a predetermined position. Similar to the distance sensor 18 of the first embodiment, the sensor body 21B uses a non-contact type sensor that utilizes infrared light, laser, ultrasound, etc. The moving mechanism 21C is configured such that the sensor body 21B is attached to a toothed belt extending along the entire length of the casing 21A, and the toothed belt is rotated by a motor capable of controlling the rotational speed. The moving mechanism 21C may also be configured to move the sensor body 21B using a ball screw or a rack and pinion.

[0055] As shown in Figure 9, the range of movement of the sensor body 21B of the mobile distance sensor 21 is such that the distance to the track 11 can be measured at three locations: above the drive wheel 9, above the rear upper roller 12, and above the midpoint between the drive wheel 9 and the rear upper roller 12; and above the idler wheel 10, above the front upper roller 12, and above the midpoint between the idler wheel 10 and the front upper roller 12.

[0056] Specifically, the range of motion of the sensor body 21B is set to be in front of the arc Q2 with radius R2 that passes through the center points B, E, H, and M of the upper roller 12 with the pivot center O, and behind the arc Q3 with radius R3 that passes through the center points A and G of the sprocket 9B of the drive wheel 9 and the center points D and K of the idler wheel 10 with the pivot center O.

[0057] As shown by the dashed line P3 in Figure 9, when the upper rotating body 4 rotates approximately 30 degrees clockwise in a plan view and the mobile distance sensor 21 is positioned above the center point A, the mobile distance sensor 21 moves its sensor body 21B to the position of the arc Q3. As a result, at P3 of the upper rotating body 4, the sensor body 21B is positioned on the center point A of the sprocket 9B of the drive wheel 9, and the distance S2 between the sensor body 21B and the left track 11 can be measured.

[0058] Next, as shown by the dashed line at P4 in Figure 9, when the upper rotating body 4 rotates approximately 45 degrees clockwise in a plan view, and the mobile distance sensor 21 is positioned above the midpoint C, the mobile distance sensor 21 moves its sensor body 21B to the position of the arc Q1. As a result, at P4 of the upper rotating body 4, the sensor body 21B is positioned on the midpoint C between the drive wheel 9 and the rear upper roller 12, and the distance S3 between the sensor body 21B and the left track 11 can be measured.

[0059] Furthermore, as shown by the dashed line at P5 in Figure 9, when the upper rotating body 4 rotates approximately 65 degrees clockwise in a plan view, and the mobile distance sensor 21 is positioned above the center point B, the mobile distance sensor 21 moves its sensor body 21B to the position of the arc Q2. As a result, at P5 of the upper rotating body 4, the sensor body 21B is positioned above the center point B of the rear upper roller 12, and the distance S4 between the sensor body 21B and the left track 11 can be measured.

[0060] In this case, wear on the track 11, drive wheel 9 (sprocket 9B), and upper roller 12 can be recognized from the changes in distance S2 and S4. This allows for the accurate calculation of the track 11's sag based on distance S3, taking into account the wear on the track 11, drive wheel 9 (sprocket 9B), and upper roller 12 (subtracting the wear).

[0061] The measurement procedures at center point D, center point E, midpoint F, center point G, center point H, midpoint J, center point K, center point M, and midpoint N are the same as those at center point A, center point B, and midpoint C, so the explanation is omitted.

[0062] Thus, in this second embodiment, the same functions and effects as those of the first embodiment described above can be obtained. In particular, in the second embodiment, the sensor body 21B of the movable distance sensor 21 is positioned to measure the distance to the track 11 at three locations: above the drive wheel 9, above the rear upper roller 12, and above the midpoint between the drive wheel 9 and the rear upper roller 12, and at three locations: above the idler wheel 10, above the front upper roller 12, and above the midpoint between the idler wheel 10 and the front upper roller 12. As a result, the movable distance sensor 21 can calculate the accurate amount of slack in the track 11 based on the distance S3, after subtracting the wear of the track 11, drive wheel 9 (sprocket 9B), and upper roller 12.

[0063] Furthermore, the sensor body 21B of the movable distance sensor 21 is movably mounted on the upper rotating body 4. Specifically, the sensor body 21B of the movable distance sensor 21 is equipped with a sensor body 21B that can move over distances corresponding to the range from the drive wheel 9 to the rear upper roller 12 or from the idler wheel 10 to the front upper roller 12. This allows measurement to be taken by moving a single sensor body 21B even at measurement positions with different distances from the pivot center O.

[0064] In the first embodiment, the example described was one in which a distance sensor 18 is provided on the slewing frame 17 of the upper slewing body 4, positioned at the midpoint C between the drive wheel 9 and the rear upper roller 12 (on the arc Q1 drawn with radius R1 from the slewing center O). However, the present invention is not limited to this, and may be configured as shown in the modified examples in Figures 10 and 11. Specifically, as shown in Figure 11, in addition to the distance sensor 18 provided on the arc Q1, one distance sensor 31 may be provided on the arc Q2 of the second embodiment, and one distance sensor 32 may be provided on the arc Q3. This makes it possible to calculate the accurate amount of slack in the track 11 after subtracting the wear of the track 11, drive wheel 9 (sprocket 9B), idler wheel 10, and upper roller 12, as in the second embodiment.

[0065] In the first embodiment, the tension (slack) of the left track 11 is measured at two locations: midpoint C, where the left track 11 is significantly slack, approximately midway between the drive wheel 9 and the rear upper roller 12; and midpoint F, where the left track 11 is significantly slack, approximately midway between the idler wheel 10 and the front upper roller 12. The tension (slack) of the right track 11 is also measured at two locations, midpoints J and N. However, the present invention is not limited to this, and a configuration in which the tension (slack) is measured at one location for the left track 11 and one location for the right track 11 is also possible.

[0066] In the first embodiment, the distance sensor 18 was provided on the left side frame 17F of the swivel frame 17, and in the second embodiment, the movable distance sensor 21 was provided on the under cover 17H of the swivel frame 17 as an example. However, the present invention is not limited to these, and the distance sensor 18 and the movable distance sensor 21 may be provided in other locations on the swivel frame 17.

[0067] Furthermore, in the embodiments, a hydraulic excavator 1 was used as an example of construction machinery for explanation. However, the present invention is not limited to this and can be broadly applied to other construction machinery equipped with a slewing device, such as a hydraulic crane. [Explanation of symbols]

[0068] 1. Hydraulic excavator (construction machinery) 2 Lower running body 3. Swivel device 4. Upper rotating body 6 Track Frames 8 (8C, 8D) Track Side Frame 9 Drive wheels 9B sprocket 10 Idle Wheel 11 Tracks 12 Upper roller 18,31,32 Distance Sensor O Swivel center 21. Mobile distance sensor (distance sensor) 21B Sensor body A,B,D,E,G,H,K,M lines (center point) C,F,J,N Midpoint (line) S1, S2, S3, S4 Distance from distance sensor to track

Claims

1. It comprises a self-propelled lower traveling body and an upper rotating body that is rotatably mounted on the lower traveling body, The aforementioned lower traveling body is A track frame with track side frames extending in the front-to-back direction on both the left and right sides, A drive wheel provided at one end of the track side frame in the longitudinal direction, A freewheel is provided at the other end in the longitudinal direction of the aforementioned track side frame, A track wrapped around the drive wheel and the idler wheel, An upper roller is provided on the upper part of the track side frame and supports the track from below, In a construction machine equipped with, A distance sensor for measuring the distance to the track is provided at the bottom of the upper rotating body. The construction machine is characterized in that the distance sensor is positioned to pass through at least one of the following locations when the upper rotating body rotates: near the midpoint between the drive wheel and the upper roller, or near the midpoint between the idler wheel and the upper roller.

2. A self-propelled lower traveling body and an upper rotating body rotatably mounted on the lower traveling body, The aforementioned lower traveling body is A track frame with track side frames extending in the front-to-back direction on both the left and right sides, A drive wheel provided at one end of the track side frame in the longitudinal direction, A freewheel is provided at the other end in the longitudinal direction of the aforementioned track side frame, A track wrapped around the drive wheel and the idler wheel, An upper roller is provided on the upper part of the track side frame and supports the track from below, In a construction machine equipped with, A distance sensor for measuring the distance to the track is provided at the bottom of the upper rotating body. The construction machine is characterized in that the distance sensor is positioned to measure the distance to the track at one or both of the following locations: above the drive wheel, above the upper roller, and above the midpoint between the drive wheel and the upper roller, or above the idler wheel, above the upper roller, and above the midpoint between the idler wheel and the upper roller.

3. In the construction machine described in claim 2, The construction machine is characterized in that the distance sensor is mounted so as to be movable in the front-rear direction relative to the upper rotating body.

4. comprising a self-propelled lower traveling body and an upper rotating body rotatably mounted on the lower traveling body, The aforementioned lower traveling body is A track frame with track side frames extending in the front-to-back direction on both the left and right sides, A drive wheel provided at one end of the track side frame in the longitudinal direction, A freewheel is provided at the other end in the longitudinal direction of the aforementioned track side frame, A track wrapped around the drive wheel and the idler wheel, An upper roller is provided on the upper part of the track side frame and supports the track from below, In a construction machine equipped with, A distance sensor for measuring the distance to the track is provided at the bottom of the upper rotating body. The distance sensor is mounted on the upper rotating body so as to be movable in the front-rear direction, and is provided to be movable over a distance corresponding to the range from the drive wheel to the upper roller or the range from the idler wheel to the upper roller, in a construction machine.

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