JP7835593B2 - Construction machinery - Google Patents

Description

This invention relates to a construction machine equipped with a lower running body that moves by rotating its tracks.

A typical example of construction machinery, the hydraulic excavator, comprises a self-propelled tracked lower chassis, a rotatable upper slewing body mounted on the lower chassis, and a working device rotatably mounted at the front of the upper slewing body.

The lower running gear comprises a track frame with track side frames extending in the front-rear direction on both the left and right sides, a drive wheel at the rear end (one end in the longitudinal direction of the track side frame), a idler wheel at the front end (the other end in the longitudinal direction of the track side frame), and a track belt wrapped around the drive wheel and the idler wheel. The lower running gear also includes upper rollers on the top of the track side frames to support the track belt from below.

In tracked lower chassis, the idler wheels are mounted to be movable in the longitudinal direction relative to the track side frame. Between the idler wheels and the track side frame, a track tensioning device is provided, which adjusts the track tension by controlling the amount of grease injected into the adjuster cylinder. This allows the lower chassis to measure the track tension (slack) and adjust the amount of grease injected into the adjuster cylinder of the track tensioning device based on the measurement result, thereby adjusting the track tension so that the appropriate load is applied to the drive wheels, idler wheels, upper rollers, and tracks.

To measure the track tension, the upper slewing unit is rotated 90 degrees relative to the lower running unit, and the working device is pressed against the ground to lift one of the tracks. In this position, the distance from the track side frame to the track is measured as the track tension (slack).

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).

Japanese Unexamined Patent Publication No. 7-108961

The hydraulic excavator described in Patent Document 1 has a distance sensor located on the underside of the track side frame. Therefore, to measure 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 for operating the work device and a large workspace that allows for rotation with the work device extended. Furthermore, 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, raising concerns about damage to the distance sensor from these objects.

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

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 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 to pass through at least one of the midpoint between the drive wheel and the upper roller, or the midpoint between the idler wheel and the upper roller, when the upper rotating body rotates .
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.

According to this invention, the tension of the track can be measured even with limited working time and in a confined workspace, and damage to the distance sensor due to soil and rocks can be prevented.

This is a left side view showing a hydraulic excavator applied to the first embodiment of the present invention. This is a left side view showing the rear portion of a hydraulic excavator. This is a plan view showing the lower running gear with the tracks omitted. This is a plan view showing the swivel frame and distance sensor. This is a plan view showing the positional relationship between the distance sensors of the lower traveling body and the upper rotating body. 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. 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. This is a plan view showing the rotating frame and distance sensor (mobile sensor device). This is a plan view showing the upper rotating body rotated so that the distance sensors are positioned on the top of the drive wheels, on the top of the upper rollers, and at the track tension measurement points. This is a left side view showing three distance sensors according to a modified version of the present invention, together with the rear portion of a hydraulic excavator. This is a plan view showing the positional relationship between the three distance sensors on the lower traveling body and the upper rotating body.

Hereinafter, a hydraulic excavator equipped with a tracked lower travel body will be used as a representative example of a construction machine according to the embodiment of the present invention and will be described in detail with reference to the attached drawings. In this embodiment, the side of the upper slewing body where the working device is provided will be considered the front, and the side where the counterweight is provided will be considered the rear. Similarly, the side of the lower travel body where the idler wheels are provided will be considered the front, and the side where the drive wheels are provided will be considered the rear.

Figures 1 to 6 show a first embodiment of the present invention. In Figure 1, the tracked hydraulic excavator 1 comprises a self-propelled lower vehicle 2, an upper slewing body 4 rotatably mounted on the lower vehicle 2 via a slewing device 3, and a work device 5 rotatably mounted at the front of the upper slewing body 4 for excavating earth and sand. The slewing device 3 is a mechanism that rotates the upper slewing body 4 on the lower vehicle 2. The slewing device 3 comprises a slewing wheel 3A consisting of an annular bearing provided between the track frame 6 of the lower vehicle 2 and the slewing frame 17 of the upper slewing body 4, and a slewing motor (not shown) that meshes with the inner ring of the slewing wheel 3A to rotate the upper slewing body 4. The state in which the front and rear of the upper slewing body 4 and the front and rear of the lower vehicle 2 are aligned, as shown in Figure 1, is called the basic position.

The tracked lower running gear 2 is designed for travel on uneven terrain, muddy areas, etc. As shown in Figures 1 to 3, the lower running gear 2 consists of the track frame 6, drive wheels 9, idler wheels 10, tracks 11, upper rollers 12, and lower rollers 13, which will be described later.

The track frame 6 comprises a track center frame 7 located in the center in the left-right direction (the width direction of the lower running body 2), and track side frames 8 provided on both the left and right sides of the track center frame 7.

The truck center frame 7 is formed as a fabricated structure with an overall X-shape or H-shape by welding together multiple steel plates. The truck center frame 7 has a cylindrical section 7A located in the center and projecting upwards. The slewing wheel 3A of the slewing device 3 is mounted on this cylindrical section 7A. The center of the cylindrical section 7A and the slewing wheel 3A forms the slewing center O of the upper slewing body 4 (see Figures 3, 4, etc.).

The track side frames 8 are provided on both the left and right sides of the track center frame 7, extending in the front-to-back direction. The track side frames 8 are arranged symmetrically on both sides of the track center frame 7. The track side frames 8 are formed as rectangular tubes extending in the front-to-back direction. A drive wheel bracket 8A is provided at the rear end, which is one end in the longitudinal direction of the track side frame 8. On the other hand, a freewheel bracket 8B is provided at the front end, which is the other end in the longitudinal direction of the track side frame 8. Furthermore, two upper rollers 12 are provided on the upper part of the track side frames 8, spaced apart in the front-to-back direction.

The drive wheel 9 is mounted on a drive wheel bracket 8A located at the rear end of the track side frame 8, which is one end in the longitudinal direction. The drive wheel 9 comprises a reduction gear 9A attached to the drive wheel bracket 8A, a travel 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 circumference of the sprocket 9B engages with the track 11.

The idler wheel 10 is mounted on the idler wheel bracket 8B, located at the front end of the track side frame 8, which is 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. Furthermore, 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 allows for adjustment of the track tension by adjusting the amount of grease injected into the adjuster cylinder.

The track 11 is wrapped around the drive wheel 9 and the idler wheel 10. For example, the track 11 is composed of numerous track links connected in the circumferential direction and numerous track shoes attached to each track link. Here, even slight wear on the connecting portion between track links can cause the track 11 to stretch and sag due to the combined wear of the numerous track links. Furthermore, wear 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 can also cause the track 11 to sag. When the track 11 sags in this way, it may hinder smooth switching between forward and reverse movement, increase running noise, and cause vibrations. Therefore, it is desirable to periodically adjust the tension (sag) of the track 11.

The upper rollers 12 are mounted 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.

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. For example, multiple lower rollers 13 are provided, spaced apart in the front-rear direction, for example, seven rollers in total.

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, housing 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 operating levers (neither shown) for driving and working, located in front of, to the left of, and to the right of the driver's seat, for operating the hydraulic excavator 1.

The slewing frame 17 forms the bottom of the upper slewing body 4. As shown in Figure 4, the slewing frame 17 includes a flat bottom plate 17A made of thick steel plate or the like, extending in the front-rear direction; left vertical plates 17B and 17C erected on the bottom plate 17A and extending in the front-rear direction at predetermined intervals in the left-right direction; multiple left overhang beams 17D extending to the left from the bottom plate 17A and left vertical plate 17B at intervals in the front-rear direction; multiple right overhang beams 17E extending to the right from the bottom plate 17A and 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.

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.

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

The distance sensor 18 is mounted 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 mounted near the rear of the left side frame 17F of the slewing frame 17. The distance sensor 18 uses a non-contact type sensor, such as infrared, laser, or ultrasonic. In environments where dust and soil are scattered, an ultrasonic distance sensor, which is less affected by dust and soil, is suitable. The distance sensor 18, for example, has a cylindrical appearance and is screwed into an insertion hole formed in the lower part of the left side frame 17F, inserted vertically.

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 at least one of the following locations: approximately midway between the drive wheel 9 and the rear upper roller 12, and approximately midway between the idler wheel 10 and the front upper roller 12.

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 (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.

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 passing 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.

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 allows the tension (slack) of the track 11 to be measured based on the distance S1 at the point where the left track 11 slackens significantly, approximately midway between the drive wheel 9 and the rear upper roller 12.

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 point where the left track 11 slackens significantly, approximately midway 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. This midpoint F is located on or near the arc Q1. As a result, the midpoint F where the left track 11 slackens significantly, approximately midway between the idler wheel 10 and the front upper roller 12, is located on the same arc Q1 as the distance sensor 18.

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 itself 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.

On the other hand, a straight line extending vertically through the center of the drive wheel 9 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 point where the right track 11 sags significantly, approximately midway 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, approximately midway between the drive wheel 9 and the rear upper roller 12, is located on the same arc Q1 as the distance sensor 18.

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 itself and the right track 11. This allows the tension (slack) of the track 11 to be measured at the point where the right track 11 slackens significantly, approximately midway between the drive wheel 9 and the rear upper roller 12.

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 point where the right track 11 slackens significantly, approximately midway 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 slackens significantly, approximately midway between the idler wheel 10 and the front upper roller 12, is located on the same arc Q1 as the distance sensor 18.

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 itself and the right track 11. This allows the tension (slack) of the track 11 to be measured at the point where the right track 11 slackens significantly, approximately midway between the idler wheel 10 and the front upper roller 12.

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, using the distance sensor 18. 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 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.

Next, we will explain 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.

When measuring the tension (slack) of the track 11, accurate measurements can be obtained by maintaining a consistent measurement environment. First, position the hydraulic excavator 1 on a flat surface suitable for measuring the track tension 11. The required space in this case is enough room for the upper rotating body 4 to rotate with the working device 5 raised and then folded. In other words, by ensuring sufficient space for the upper rotating body 4 to rotate, the track tension 11 can be measured. Furthermore, as a preparatory step before measuring the track tension 11, the hydraulic excavator 1 (lower traveling body 2) is slowly moved forward and stopped to ensure a consistent track condition.

After stopping the hydraulic excavator 1, the work device 5 is raised and then folded down. Next, with the track tension measurement switch 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 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 the distance sensor 18 is positioned on midpoints F, J, and N.

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 track tension exceeds the threshold, the track tension 11 is adjusted.

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

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 perform tasks such as rotating the upper slewing body 4 and excavating soil using the work device 5.

The tracks 11 of the hydraulic excavator 1 will slacken (relative stretch) if wear occurs, for example, at the connecting parts between track links, 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. Therefore, the hydraulic excavator 1 undergoes periodic measurement and adjustment of the track tension 11. The track tension adjustment is performed by injecting grease into the adjuster cylinder of the track tensioning device located between the idler wheel 10 and the track side frame 8, thereby increasing the track tension and decreasing the slack.

Thus, according to this embodiment, the slewing frame 17, which serves as the bottom of the upper slewing body 4 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. Furthermore, the distance sensor 18 measures the distance to the upper surface of the track 11.

This allows the tension (slack) of the track 11 to be measured without lifting the track 11. As a result, the tension of the track 11 can be easily measured even with limited working time and in a confined workspace.

Furthermore, since the distance sensor 18 is mounted 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.

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 traveling body 2. Therefore, by simply rotating the upper rotating body 4 once on the lower traveling 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 measurements at two points for each track 11, improving the reliability of the measured values.

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, allowing for clear measurement of the amount of slack in the track 11.

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 within a range corresponding to either the range from the drive wheel to the upper roller or the range from the idler wheel to the upper roller. In this second embodiment, the same reference numerals are used for the same components as in the first embodiment described above, and their descriptions are omitted.

In Figure 7, the movable distance sensor 21, acting 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 mounted on 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.

For example, the mobile distance sensor 21 comprises a long, box-shaped casing 21A extending in the front-to-back direction and attached to the under cover 17H, a sensor body 21B mounted 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 utilizing 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 its 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.

As shown in Figure 9, the range of movement of the sensor body 21B of the mobile distance sensor 21 allows for measurement of 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 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.

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, centered on 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, centered on the pivot center O.

As shown by the dashed line at 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.

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.

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, allowing it to measure the distance S4 between the sensor body 21B and the left track 11.

In this case, the wear of 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 slack based on distance S3, taking into account the wear of the track 11, drive wheel 9 (sprocket 9B), and upper roller 12 (subtracting the wear).

Furthermore, the measurement procedures at center points D, E, F, G, H, J, K, M, and N are the same as those at center points A, B, and C, so the explanation is omitted.

Thus, in this second embodiment, substantially 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 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. This allows the movable distance sensor 21 to 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.

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.

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 arc Q1, one distance sensor 31 may be provided on arc Q2 and one distance sensor 32 on arc Q3, as in the second embodiment. This allows for the accurate calculation of the 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.

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

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, a movable distance sensor 21 was provided on the under cover 17H of the swivel frame 17. However, the present invention is not limited to these configurations, and the distance sensor 18 and the movable distance sensor 21 may be provided in other locations on the swivel frame 17.

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.

1. Hydraulic excavator (construction machinery)
2 Lower running body 3 Turning mechanism 4 Upper turning body 6 Track frame 8 (8C, 8D) Track side frame 9 Drive wheel 9B Sprocket 10 Idle wheel 11 Track 12 Upper roller 18, 31, 32 Distance sensor 0 Turning 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 (4)

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 . 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 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. 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. 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 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.