Slewing gear of construction machinery

Abstract

To provide a slewing gear of a construction machinery in which an amount of foreign substance occurred in a gear device can be precisely detected.SOLUTION: A slewing gear 7 includes: a speed reduction device 22 having a gear mechanism 24 that transmits a rotational drive force of the slewing motor 21 and outputs the rotational drive force to a slewing wheel 6 and an output shaft 25 and a casing 26 housing the gear mechanism 24 and the output shaft 25; and a sensor 71 detecting the foreign substance accumulated in the casing 26. The gear mechanism 24 and the output shaft 25 are arranged in such a manner that a rotational axial line thereof extends in a vertical direction. The casing 26 includes a peripheral groove 60 extending in an entire periphery in a circumferential direction at a position on a lower side of an engagement portion of the gear mechanism 24 on an inner wall surface 45a. The peripheral groove 60 opens upward and has a downward direction as a depth direction. The peripheral groove 60 includes an inclined bottom surface 60a with a first position 601 in a circumferential direction being the shallowest portion and the second position 602 being the deepest portion, in which the inclination becomes gradually deeper as it goes from the first position 601 to the second position 602. The sensor 71 is arranged at a position corresponding to the second position 602 of the peripheral groove 60.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a slewing device for a construction machine, and more particularly to a slewing device for a construction machine equipped with a gear device that transmits the rotational drive force of a slewing drive source. [Background technology]

[0002] Construction machines such as hydraulic excavators equipped with a rotating body are equipped with a rotating device that rotates the rotating body. The rotating device is equipped with a gear device that transmits the rotational driving force of a rotating drive source such as a hydraulic motor or an electric motor. The gear device of the rotating device houses components such as gears and bearings in a casing, and lubricating oil for lubricating the components is sealed in the casing. In the gear device, foreign matter such as metal powder and broken pieces generated by wear of components such as gears may be mixed into the lubricating oil. If foreign matter is mixed into the lubricating oil, there is a concern that it may cause damage to gears, bearings, oil seals, etc.

[0003] In response to such concerns, a technique is known for detecting foreign matter mixed into the lubricating oil sealed inside the casing of the gear device (see, for example, Patent Document 1). In the reducer described in Patent Document 1, a sensor is attached at a predetermined position so as to detect sludge (foreign matter) accumulated on the input shaft housed in the case, the carrier of the reduction mechanism, or the case. It is possible to estimate the life of the reducer based on the amount of accumulated sludge (foreign matter) detected by the sensor. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 63-67467 Summary of the Invention [Problem to be solved by the invention]

[0005] In the reducer described in Patent Document 1, the sludge that accumulates on the input shaft and carrier, which are rotating members, is only a part of the sludge generated in the reducer. In addition, in the structure of the reducer, the area in which the sludge accumulated on the case can be detected by a sensor is limited. In other words, it is difficult to detect most of the sludge generated in the reducer described in Patent Document 1 by a sensor. For this reason, it is difficult to accurately estimate the life of the reducer or the appropriate timing for maintenance from the amount of accumulated sludge detected by the sensor.

[0006] The present invention has been made to solve the above-mentioned problems, and its object is to provide a turning device for a construction machine that is capable of accurately grasping the amount of foreign matter generated within the gear device. [Means for solving the problem]

[0007] The present application includes a number of means for solving the above problems. One example of such means is a construction machine including a slewing drive source that generates a rotational drive force for rotating a slewing body of a construction machine, a gear mechanism that transmits the rotational drive force of the slewing drive source, an output shaft that outputs the rotational drive force transmitted to the gear mechanism to a slewing ring of the construction machine, a gear device having a casing that houses the gear mechanism and the output shaft and stores lubricating oil that lubricates the gear mechanism, and a sensor that detects foreign matter accumulated in the casing, and the gear device is disposed so that the rotation axis of the gear mechanism and the output shaft extends in the vertical direction of the slewing body. In the rotating device, the casing has a circumferential groove extending around the entire circumferential direction of the inner wall surface at a position on the inner wall surface lower than the meshing portion of the gear mechanism, the circumferential groove is a groove that opens upward in the up-down direction and has a depth direction in the downward direction, the circumferential groove has a shallowest part at a first position in the circumferential direction and a deepest part at a second position different from the first position in the circumferential direction, and has a bottom surface that is inclined so as to gradually become deeper from the first position toward the second position, and the sensor is arranged at a position corresponding to the second position of the circumferential groove. Effect of the Invention

[0008] According to one embodiment of the present invention, a circumferential groove that is open upward and has a depth direction downward is provided on the entire circumference of the inner wall surface of the casing, so that most of the foreign matter generated in the gear mechanism can be settled at some position in the circumferential groove. Furthermore, by slanting the bottom surface of the circumferential groove from the shallowest part to the deepest part, the foreign matter that has settled in the circumferential groove can be accumulated in the deepest part of the circumferential groove. Since the foreign matter accumulated in the deepest part of the circumferential groove is detected by a sensor, the amount of foreign matter generated in the gear device can be accurately grasped. Problems, configurations and effects other than those described above will become apparent from the following description of the embodiments. [Brief description of the drawings]

[0009] [Figure 1] 1 is an external view showing a hydraulic excavator equipped with a swing device for a construction machine according to a first embodiment of the present invention. [Diagram 2] 1 is a vertical sectional view showing a turning device of a construction machine according to a first embodiment. [Diagram 3] 3 is a schematic perspective view showing the structure of a circumferential groove of a casing of a reduction gear in the slewing device of the construction machine according to the first embodiment shown in FIG. 2. FIG. [Figure 4] 3 is a schematic cross-sectional view showing the structure of a circumferential groove of a casing of a reduction gear in the slewing device of the construction machine according to the first embodiment shown in FIG. 2. [Diagram 5] 5 is a cross-sectional view taken along the line VV of the arrows showing the structure of a circumferential groove of a casing of a reduction gear in a slewing device of the construction machine according to the first embodiment shown in FIG. 4. [Figure 6] 3 is a schematic cross-sectional view showing the configuration and structure of a sensor unit in a swing device of the construction machine according to the first embodiment shown in FIG. 2. [Figure 7] 10 is a schematic perspective view showing a circumferential groove of a casing of a reduction gear device in a swing device of a construction machine according to a first modified example of the first embodiment. FIG. [Figure 8] 8 is an enlarged cross-sectional view showing the structure of a circumferential groove at a position where a sensor unit is arranged in a swing device of a construction machine according to a first modified example of the first embodiment shown in FIG. 7. [Figure 9]13 is a schematic cross-sectional view showing a circumferential groove of a casing of a reduction gear device in a swing device of a construction machine according to a second modified example of the first embodiment. FIG. [Figure 10] 10 is an enlarged cross-sectional view showing the structure of a circumferential groove at the arrangement position of a sensor unit in a swing device of a construction machine according to a second modified example of the first embodiment shown in FIG. 9. [Figure 11] 10 is a schematic cross-sectional view showing a circumferential groove of a casing of a reduction gear in a swing device of a construction machine according to a second embodiment of the present invention. FIG. [Figure 12] 12 is an enlarged cross-sectional view showing the structure of a circumferential groove at the position where a sensor unit is arranged in the slewing device of the construction machine according to the second embodiment shown in FIG. 11. [Figure 13] FIG. 11 is a vertical sectional view showing a swing device for a construction machine according to a third embodiment of the present invention. [Figure 14] FIG. 11 is a schematic perspective view showing, in a see-through state, a circumferential groove of a casing of a reduction gear device in a slewing device for a construction machine according to a fourth embodiment of the present invention. [Figure 15] 15 is a schematic cross-sectional view showing a circumferential groove of a casing of a reduction gear in a swing gear of a construction machine according to a fourth embodiment shown in FIG. 14. [Figure 16] FIG. 11 is a vertical sectional view showing a swing device for a construction machine according to a fifth embodiment of the present invention. [Figure 17] 17 is a schematic cross-sectional view showing the positional relationship between a sensor unit and a valve mechanism in a swing device of a construction machine according to a fifth embodiment shown in FIG. 16. [Figure 18] 18 is an explanatory diagram showing the operation and action of a valve mechanism in a swing device of a construction machine according to the fifth embodiment shown in FIG. 17. [Figure 19] FIG. 13 is a configuration diagram showing a network of multiple computers that utilizes detection data from sensors in a swing device of a construction machine according to a sixth embodiment of the present invention. [Figure 20] 20 is a flowchart showing an example of a procedure for diagnosing the lubricant for the swing device performed by a server of the network shown in FIG. 19. [Figure 21] FIG. 13 is a diagram showing an example of a change in height (accumulation amount) of foreign matter with respect to operation time in a swing device of a construction machine according to a sixth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, an embodiment of a swing device for a construction machine according to the present invention will be described with reference to the drawings. In this embodiment, a hydraulic excavator will be taken as an example of a construction machine. In this specification, front, rear, left and right refer to directions as seen by an operator riding on the construction machine.

[0011] [First embodiment] First, a schematic configuration of a hydraulic excavator as an example of a construction machine equipped with a swing gear for a construction machine according to a first embodiment of the present invention will be described with reference to Fig. 1. Fig. 1 is an external view showing a hydraulic excavator equipped with a swing gear for a construction machine according to the first embodiment.

[0012] In Fig. 1, a hydraulic excavator 1 as a construction machine includes a self-propelled running body 2, a rotating body 3 rotatably mounted on the running body 2, and a working device 4 provided on the front side of the rotating body 3 so as to be capable of ascending and descending. The rotating body 3 is rotatably supported on the running body 2 via a slewing wheel 6. The hydraulic excavator 1 is configured to perform work such as excavating and loading earth and sand by combining the rotating operation of the rotating body 3 and the operation of the working device 4. The configuration of the slewing wheel 6 will be described later.

[0013] The running body 2 has, for example, endless track (crawler) type running devices 11 on the left and right sides. An inner wheel 6a (to be described later) of a swivel wheel 6 (see FIG. 2 to be described later) is attached and fixed to the upper end of the running body 2.

[0014] The rotating body 3 includes a rotating frame 12 as a support structure, a cab 13 installed on the front left side of the rotating frame 12 and in which an operator sits, a machine room 14 formed on the rear side of the rotating frame 12, and a counterweight 15 attached to the rear end of the rotating frame 12. Various operating devices (not shown) for operating the hydraulic excavator 1 are arranged in the cab 13. The machine room 14 accommodates, for example, various hydraulic devices that constitute a hydraulic system that drives the hydraulic excavator 1. The counterweight 15 provides balance with the working device 4.

[0015] The swivel body 3 is configured to rotate relative to the running body 2 by transmitting the rotational driving force of the swivel device 7 to the swivel ring 6. An outer wheel 6b (described later) of the swivel ring 6 (see FIG. 2 described later) is attached and fixed to the swivel frame 12. The configuration and structure of the swivel device 7 will be described in detail later.

[0016] The rotating body 3 is equipped with a controller 8 that performs processing to diagnose abnormalities in the rotating device 7, and a wireless communication device 9 for communicating data processed by the controller 8 with an external terminal. The controller 8 includes a processor (e.g., a CPU) and a storage device (e.g., a memory), and the processor executes various processes based on programs stored in the storage device.

[0017] The working device 4 is a multi-joint working device configured by rotatably connecting multiple driven members. The multiple driven members are configured, for example, with a boom 16, an arm 17, and a bucket 18 as a working tool (attachment). The attachment can be replaced with various attachments such as a grapple, a breaker, and a lifting magnet.

[0018] Next, the configuration and structure of the slewing device of the construction machine according to the first embodiment will be described with reference to Fig. 2. Fig. 2 is a vertical sectional view showing the slewing device of the construction machine according to the first embodiment.

[0019] In FIG. 2, the slewing device 7 outputs a rotational driving force for rotating the slewing body 3 (see FIG. 1) to the slewing ring 6, thereby rotating the slewing body 3 relative to the traveling body 2 (see FIG. 1).

[0020] The slewing ring 6 has an inner ring 6a attached to the upper end (a cylindrical body, not shown) of the running body 2, an outer ring 6b attached to the lower surface side of the revolving frame 12 of the revolving body 3, and a plurality of rolling elements 6c (only one is shown in FIG. 2) disposed between the inner ring 6a and the outer ring 6b. Internal teeth 6d are formed all around the inner circumference of the inner ring 6a. The outer ring 6b fixed to the revolving frame 12 of the revolving ring 6 rotates around the outer circumference of the inner ring 6a fixed to the running body 2 by the rotational driving force of the revolving device 7. This causes the revolving body 3 to revolve on the running body 2.

[0021] The slewing device 7 includes a slewing motor 21 serving as a slewing drive source that generates a rotational drive force for rotating the slewing body 3 , and a gear device 22 that transmits the rotational drive force of the slewing motor 21 to the slewing ring 6 .

[0022] The swing motor 21 has a motor shaft 21a that outputs a rotational driving force to the gear device 22. The motor shaft 21a of the swing motor 21 extends in the vertical direction of the construction machine 1 (swing body 3). A shaft spline (not shown) is formed on the motor shaft 21a of the swing motor 21. The swing motor 21 is attached to the upper end of a casing 26 (described below) of the gear device 22, and is configured so that the motor shaft 21a extends within the casing 26. The swing motor 21 can be configured as a hydraulic or electric motor.

[0023] The gear device 22 is configured as, for example, a reduction gear that reduces the speed of the rotational driving force of the slewing motor 21 before transmitting it. The reduction gear device 22 includes a gear mechanism 24 that reduces the speed of the rotational driving force of the slewing motor 21 before transmitting it, an output shaft 25 that outputs the rotational driving force transmitted to the gear mechanism 24 to the slewing ring 6, and a casing 26 that houses the gear mechanism 24 and the output shaft 25. The gear mechanism 24 and the output shaft 25 are disposed so that their rotation axes extend in the vertical direction, and the gear mechanism 24 is disposed so that it is located above the output shaft 25. The casing 26 is installed on the slewing frame 12 so that a cylindrical portion that houses the gear mechanism 24 and the output shaft 25 extends in the vertical direction.

[0024] The gear mechanism 24 is, for example, a planetary gear mechanism. The planetary gear mechanism 24 has a sun gear 31 coupled to the motor shaft 21a of the slewing motor 21, a plurality of (for example, three) planetary gears 32 (only one is shown in FIG. 2) meshing with the sun gear 31 and internal teeth 36 of the casing 26, which will be described later, and a carrier 33 that rotatably supports the planetary gears 32 with support pins 34. The sun gear 31 rotates integrally with the motor shaft 21a of the slewing motor 21, and is coupled to the motor shaft 21a of the slewing motor 21 by, for example, a spline coupling. Each planetary gear 32 revolves around the sun gear 31 while rotating on its own axis in association with the rotation of the sun gear 31 between the sun gear 31 and the internal teeth 36 of the casing 26. The support pin 34 is fixed to the carrier 33 in a state where it is inserted into the rotation center of the planetary gear 32. The carrier 33 is configured to rotate at the orbital speed of the planetary gear 32 as the planetary gear 32 supported by the support pin 34 revolves. The carrier 33 has a boss portion 35 at its lower end that is coupled to one axial end (upper end) of the output shaft 25, and is configured to rotate integrally with the output shaft 25. The boss portion 35 of the carrier 33 is configured to have internal teeth or a hole spline on its inner peripheral surface, for example.

[0025] The output shaft 25 is configured such that one axial end (upper end) is coupled to the boss portion 35 of the carrier 33. The upper end of the output shaft 25 is configured to have external teeth on the outer circumferential surface that mesh with the internal teeth of the boss portion 35 of the carrier 33, or to have an axial spline 25a that is coupled to the hole spline of the boss portion 35 of the carrier 33. A pinion 25b is integrally provided on the other axial end (lower end) of the output shaft 25. The pinion 25b protrudes downward from the lower end of the casing 26 and meshes with internal teeth 6d provided on the inner ring 6a of the slewing ring 6. The output shaft 25 is rotatably supported by the casing 26 via a lower bearing 27 and an upper bearing 28. The lower bearing 27 is attached to the upper side of the output shaft 25 with a gap therebetween from the pinion 25b. The upper bearing 28 is attached below the upper end portion (the portion where the boss portion 35 of the carrier 33 is joined) of the output shaft 25 and above and spaced apart from the lower bearing 27. A sleeve 29 is press-fitted into the output shaft 25 at a position between the pinion 25b and the lower bearing 27.

[0026] The casing 26 has a lower case 41 attached to the revolving frame 12, an upper case 42 attached to the upper end of the lower case 41, and a cover 43 attached so as to cover an upper opening of the upper case 42. The cover 43 is configured as a part of the housing of the revolving motor 21, for example.

[0027] The lower case 41 has a cylindrical peripheral wall 45 extending in the vertical direction, and an annular mounting flange 46 provided at the lower end of the peripheral wall 45. The lower case 41 accommodates the output shaft 25 within the peripheral wall 45 with the pinion 25b of the output shaft 25 protruding outward from the lower side of the peripheral wall 45. A lower bearing 27 and an upper bearing 28 are fixed to a lower end and an upper portion of an inner wall surface 45a of the peripheral wall 45 of the lower case 41, respectively. The lower case 41 is fixed by fastening the mounting flange 46 to the revolving frame 12 with bolts (not shown).

[0028] The upper case 42 has a cylindrical peripheral wall 47 extending in the vertical direction, and is configured to accommodate most of the planetary gear mechanism 24. Internal teeth 36 that mesh with the planetary gears 32 of the planetary gear mechanism 24 are provided on the inner peripheral surface of the peripheral wall 47 of the upper case 42 over the entire circumference. In other words, the upper case 42 functions as a ring gear of the planetary gear mechanism 24. A plurality of bolt holes (not shown) that penetrate in the vertical direction are provided in the peripheral wall 47 of the upper case 42 and the cover 43 fixed to the upper end of the upper case 42. The upper case 42 and the cover 43 are fastened to the upper end of the lower case 41 by bolts 44 (only one is shown in FIG. 2) inserted into each bolt hole.

[0029] The casing 26 also has a function of storing lubricating oil for lubricating the components of the planetary gear mechanism 24. At the lower end of the lower case 41, a ring 51 is fixed by bolts (not shown) to the outer periphery of the sleeve 29 press-fitted to the output shaft 25. An oil seal 52 is disposed between the ring 51 located at the lower end of the lower case 41 and the sleeve 29. This seals the lubricating oil stored in the casing 26. The oil level F of the lubricating oil is located at a position that reaches the height of the sun gear 31 and the planetary gears 32, for example. A drain hole 49 for discharging the lubricating oil sealed in the casing 26 to the outside of the casing 26 is provided in a wall portion (a bulging portion 48 described later) located between the lower bearing 27 and the upper bearing 28 of the lower case 41, so as to extend from an inner wall surface 45a to an outer wall surface 45b of the peripheral wall 45 of the lower case 41 and penetrate therethrough. The external opening of the drain hole 49 is closed by a drain plug 53 .

[0030] The casing 26 according to this embodiment is characterized in that it has a structural portion that accumulates foreign matter such as wear powder and broken pieces generated in the planetary gear mechanism 24. A sensor unit 70 is disposed within the casing 26 for detecting foreign matter accumulated in the structural portion.

[0031] Next, the details of the foreign object accumulation structure and foreign object detection unit in the slewing device of the construction machine according to the first embodiment will be described with reference to Figs. 2 to 6. Fig. 3 is a schematic perspective view showing the structure of a circumferential groove of a casing of a reduction gear in the slewing device of the construction machine according to the first embodiment shown in Fig. 2. Fig. 4 is a schematic cross-sectional view showing the structure of a circumferential groove of a casing of a reduction gear in the slewing device of the construction machine according to the first embodiment shown in Fig. 2. Fig. 5 is a cross-sectional view seen from the VV arrows, showing the structure of a circumferential groove of a casing of a reduction gear in the slewing device of the construction machine according to the first embodiment shown in Fig. 4. Fig. 6 is a schematic cross-sectional view showing the configuration and structure of a sensor unit in the slewing device of the construction machine according to the first embodiment shown in Fig. 2.

[0032] 2, the casing 26 has a bulging portion 48 (thick portion) where the inner wall surface 45a side of the peripheral wall 45 bulges radially inward at a position (lower case 41) lower than the meshing portions of the planetary gear mechanism 24 (the portion where the sun gear 31 and planetary gear 32 mesh and the portion where the planetary gear 32 mesh with the internal teeth 36 of the upper case 42). That is, as shown in Figs. 2 and 3, the lower case 41 of the casing 26 has a stepped inner wall surface 45a, and has an upwardly facing annular stepped surface 48a on the inner wall surface 45a side.

[0033] As shown in Figs. 3 and 4, a circumferential groove 60 is formed on the step surface 48a, which is the upper end of the bulging portion 48 in the lower case 41, and extends around the entire circumference of the step surface 48a (peripheral wall 45). The circumferential groove 60 is a groove that opens upward and has a depth direction downward. The circumferential groove 60 is formed so that a first position 601 (left end position in Fig. 3) in the circumferential direction of the annular step surface 48a is the shallowest part, and a second position 602 (right end position in Fig. 3) that is 180° from the first position 601, which is a position different from the first position 601 in the circumferential direction, is the deepest part. As shown in Figs. 3 and 5, the circumferential groove 60 has a bottom surface 60a that is an inclined surface that gradually becomes deeper from the first position 601 (shallowest part) toward the second position 602 (deepest part). 4, the circumferential groove 60 is formed as an annular groove in which a bottom surface 61a of a first groove portion 61 extending from a first position 601 to one side in the circumferential direction to a second position 602 and a bottom surface 62a of a second groove portion 62 extending from the first position 601 to the other side in the circumferential direction to the second position 602 are connected without any step. The circumferential groove 60 is formed as a groove that is line-symmetrical with respect to a line segment connecting the first position 601, which is the shallowest position, and the second position 602, which is the deepest position. The circumferential groove 60 has a function of collecting foreign matter such as wear powder and broken pieces generated in the planetary gear mechanism 24.

[0034] 3 and 6, a recess 64 is formed at the second position 602 (deepest part) of the circumferential groove 60, recessed downward from the bottom surface 60a of the circumferential groove 60. The recess 64 is a bottomed hole with a circular cross section, as shown in Figures 3 and 4, for example. The recess 64 has the function of capturing foreign matter accumulated at the second position 602 (deepest part) of the circumferential groove 60 and preventing the diffusion of the foreign matter.

[0035] As shown in FIG. 2, the upper bearing 28 is fixed to the upper end of the bulging portion 48 of the lower case 41. That is, the upper bearing 28 is located radially inward from the circumferential groove 60. An annular shielding plate 56 that shields the upper side of the upper bearing 28 is disposed above the upper bearing 28. The shielding plate 56 is attached, for example, to the outer peripheral surface of the boss portion 35 of the carrier 33 of the planetary gear mechanism 24. The shielding plate 56 is configured as a slanted plate that is inclined downward from the base end on the boss portion 35 side (radially inner side) toward the radially outer tip 56a. The shielding plate 56 extends so that the radially outer tip 56a is located slightly above the annular step surface 48a (opening position of the circumferential groove 60) and slightly radially inward from the radially inner opening edge of the circumferential groove 60. That is, the shielding plate 56 is disposed so as not to come into contact with the stepped surface 48a of the lower case 41, thereby preventing the generation of foreign matter such as wear powder of the shielding plate 56 due to contact with the stepped surface 48a. The shielding plate 56 has an intrusion prevention function that prevents foreign matter generated at the meshing portion of the planetary gear mechanism 24 from entering the upper bearing 28 when the foreign matter settles in the lubricating oil, and a guide function that guides the foreign matter to the circumferential groove 60.

[0036] As shown in Figs. 2 and 6, a sensor unit 70 is disposed at a second circumferential position 602 corresponding to the deepest part of the circumferential groove 60. The sensor unit 70 includes a sensor 71 that detects the height (accumulation amount) of accumulated foreign matter, and is disposed so that a sensor surface 71a faces the bottom surface 64a of the recess 64. The sensor 71 may be, for example, a laser, eddy current, or capacitance type. The sensor 71 includes a circuit that outputs a detection signal corresponding to the height of the accumulated foreign matter. The sensor 71 is electrically connected to a controller 8 (see Fig. 1), and outputs a detection signal (height of foreign matter) to the controller 8.

[0037] The sensor unit 70 includes a holding member 72 that holds the sensor 71, and an attachment member 73 that attaches the sensor 71 to the lower case 41 via the holding member 72. The attachment member 73 includes a fixing portion 75 that is fixed to the outer circumferential surface of the peripheral wall 45 of the lower case 41, and a support portion 76 that stands upright from the fixing portion 75 and has a tip portion connected to the holding member 72. The attachment member 73 is attached so that the support portion 76 penetrates the peripheral wall 45 of the lower case 41. A seal member 74 (e.g., an O-ring) is attached to the outer circumferential surface of the support portion 76. The seal member 74 is sandwiched between the outer circumferential surface 45b of the peripheral wall 45 of the lower case 41 and the fixing portion 75 of the attachment member 73, and prevents leakage of lubricating oil in the casing 26 from a gap between the support portion 76 of the attachment member 73 and the peripheral wall 45 of the lower case 41. The mounting member 73 has an outlet (not shown) for taking out a signal line (not shown) of the sensor 71. The outlet of the mounting member 73 is partitioned into a first space 76a communicating with the inside of the casing 26 and a second space 76b communicating with the outside of the casing 26, and a partition 76c between the first space 76a and the second space 76b is configured to prevent the lubricating oil in the casing 26 from leaking to the outside. The mounting member 73 is provided so that a connection line having a first terminal (not shown) located in the first space 76a and a second terminal (not shown) located in the second space 76b at both ends passes through the partition 76c. The signal line of the sensor 71 is connected to the first terminal on the side of the first space 76a of the mounting member 73 into which the lubricating oil enters, while a signal line (not shown) connected to the controller 8 is connected to the second terminal on the side of the second space 76b of the mounting member 73 into which the lubricating oil cannot enter.

[0038] Next, the operation and effect of the swing device of the construction machine according to the first embodiment will be described with reference to Fig. 2. In Fig. 2, the dashed arrow indicates the movement direction of foreign matter in the lubricating oil.

[0039] When the operator of the hydraulic excavator 1 performs a swing operation, the swing motor 21 of the swing device 7 shown in Fig. 2 is rotated. The rotation of the motor shaft 21a of the swing motor 21 is reduced in speed by the planetary gear mechanism 24 of the reduction gear 22 and rotates the outer wheel 6b of the swing wheel 6 relative to the inner wheel 6a with a large torque via the output shaft 25. As a result, the swing body 3 of the hydraulic excavator 1 shown in Fig. 1 swings relative to the traveling body 2.

[0040] When the slewing device 7 shown in FIG. 2 is driven, the lubricating oil stored in the casing 26 is used to lubricate the components 31, 32, 33, 34, and 36 of the planetary gear mechanism 24. When the components (sun gear 31, planetary gear 32, carrier 33, and internal teeth 36 (ring gear)) of the planetary gear mechanism 24 mesh and rotate, the gears 31, 32, 33, and 36 wear over the course of operation, generating wear powder that settles in the lubricating oil. Some of the generated wear powder moves vertically in the lubricating oil due to its own weight, and settles while being swept radially outward by the swirling flow of the lubricating oil generated by the rotation of the planetary gear mechanism 24, thereby settling directly into the circumferential groove 60 formed in the step surface 48a on the inner wall surface 45a of the casing 26. The rest of the wear powder settles on the upper surface 56b of the shielding plate 56 located radially inward from the circumferential groove 60. The wear powder that has settled on the shielding plate 56 moves along the shielding plate 56 toward the radially outer tip 56a due to the swirling flow of the lubricating oil and the inclination of the shielding plate 56, and then settles from the tip 56a of the shielding plate 56 into the circumferential groove 60. The wear powder that has settled into the circumferential groove 60 slides down along the inclined bottom surface 60a of the circumferential groove 60 to its deepest part. As a result, most of the wear powder generated by the meshing of the planetary gear mechanism 24 accumulates in the deepest part (second position 602) of the circumferential groove 60.

[0041] The height H of the wear powder accumulated and deposited in the deepest part (second position 602) of the circumferential groove 60 is detected by the sensor 71. The sensor 71 outputs a detection signal corresponding to the detected height H of the wear powder to the controller 8 shown in Fig. 1. The controller 8 stores the detection data output from the sensor 71 in a storage device.

[0042] The data detected by the sensor 71 is used, for example, to diagnose abnormalities in the swing gear 7 and to determine when maintenance should be performed on the swing gear 7. The abnormality diagnosis of the swing gear 7 and the determination of when maintenance should be performed on the swing gear 7 based on the detection data of the sensor 71 can be performed by the controller 8 of the hydraulic excavator 1 or by a terminal such as an external computer. When the detection data of the sensor 71 is used by a terminal such as an external computer, it is also possible to configure the detection data to be successively transmitted to the external terminal by a wireless communication device 9 mounted on the hydraulic excavator 1, for example, or to have a serviceman or the like periodically copy or move the detection data of the sensor 71 to a recording medium.

[0043] In this embodiment, a circumferential groove 60) that opens upward and has a depth direction downward is formed around the entire circumferential direction at a position below the meshing portion of the planetary gear mechanism 24 on the inner wall surface 45a of the casing 26. This makes it possible for most of the foreign matter generated by the meshing of the components of the planetary gear mechanism 24 to settle somewhere in the circumferential groove 60.

[0044] Furthermore, in this embodiment, the circumferential groove 60 is formed so that a first position 601 in the circumferential direction is the shallowest part and a second position 602 different from the first position 601 is the deepest part, and the bottom surface 60a of the circumferential groove 60 is inclined so that the circumferential groove 60 gradually deepens from the first position 601 toward the second position 602. As a result, foreign matter that has settled at any position in the circumferential groove 60 slides down the bottom surface 60a of the inclined surface and reaches the deepest part of the circumferential groove 60, so that the foreign matter can accumulate in the deepest part of the circumferential groove.

[0045] In this embodiment, the upper side of the upper bearing 28 is shielded by a shielding plate 56 installed below the planetary gear mechanism 24. This prevents foreign matter generated by meshing of the planetary gear mechanism 24 from entering the upper bearing 28. In addition, the shielding plate 56 is inclined downward from a base end on the radially inner side to a tip end 56a on the radially outer side. This allows the foreign matter to be guided to the circumferential groove 60 located radially outward of the shielding plate 56, even if the generated foreign matter settles on the shielding plate 56.

[0046] In this embodiment, the lower case 41 of the casing 26 has a recess 64 recessed downward from the bottom surface 60a of the circumferential groove 60 at the second position 602, which is the deepest part of the circumferential groove 60. This makes it possible to prevent foreign matter accumulated in the recess 64 from being dispersed by the flow of the lubricating oil.

[0047] As described above, the slewing device 7 of the hydraulic excavator 1 (construction machine) according to the first embodiment includes the slewing motor 21, which is a slewing drive source that generates a rotational drive force for slewing the slewing body 3 of the hydraulic excavator 1 (construction machine), the planetary gear mechanism 24 as a gear mechanism that transmits the rotational drive force of the slewing motor 21 (slewing drive source), the output shaft 25 that outputs the rotational drive force transmitted to the planetary gear mechanism 24 (gear mechanism) to the slewing ring 6 of the hydraulic excavator 1 (construction machine), the reduction gear 22 as a gear device having a casing 26 that houses the planetary gear mechanism 24 (gear mechanism) and the output shaft 25 and stores lubricating oil that lubricates the planetary gear mechanism 24 (gear mechanism), and the sensor 71 that detects foreign matter accumulated in the casing 26 of the reduction gear 22 (gear mechanism). The reduction gear 22 (gear mechanism) is arranged so that the rotational axis of the planetary gear mechanism 24 (gear mechanism) and the output shaft 25 extends in the vertical direction of the slewing body 3. The casing 26 has a circumferential groove 60 extending around the entire circumference of the inner wall surface 45a in the circumferential direction at a position lower than the meshing portion of the planetary gear mechanism 24 (gear mechanism) on the inner wall surface 45a. The circumferential groove 60 is a groove that opens upward and has a depth direction in the downward direction. Furthermore, the circumferential groove 60 has a first position 601 in the circumferential direction as its shallowest portion and a second position 602 different from the first position 601 in the circumferential direction as its deepest portion, and has an inclined bottom surface 60a that gradually becomes deeper from the first position 601 to the second position 602. The sensor 71 is disposed at a position corresponding to the second position 602 (deepest portion) of the circumferential groove 60.

[0048] According to this configuration, by providing the circumferential groove 60, which is open upward and has a depth direction downward, on the inner wall surface 45a of the casing 26, it is possible to make most of the foreign matter generated in the planetary gear mechanism 24 (gear mechanism) settle at any position in the circumferential groove 60. Furthermore, by inclining the bottom surface 60a of the circumferential groove 60 from the shallowest part to the deepest part, it is possible to make the foreign matter that has settled at any position in the circumferential groove 60 accumulate in the deepest part of the circumferential groove 60. Since the sensor 71 detects the foreign matter accumulated in the deepest part of the circumferential groove 60, it is possible to accurately grasp the amount of foreign matter generated in the reduction gear device 22 (gear device).

[0049] In addition, in this embodiment, the circumferential groove 60 is an annular groove in which a bottom surface 61a of the first groove portion 61 extending from the first position 601 to one side in the circumferential direction to the second position 602 and a bottom surface 62a of the second groove portion 62 extending from the first position 601 to the other side in the circumferential direction to the second position 602 are connected without any steps.

[0050] According to this configuration, the depth of the deepest part of the circumferential groove 60 can be reduced while ensuring the inclination of the bottom surface 60a of the circumferential groove 60 that allows foreign matter to slide.

[0051] In this embodiment, the circumferential groove 60 is formed as a groove that is line-symmetrical with respect to a line segment connecting the first position 601 (shallowest portion) and the second position 602 (deepest portion).

[0052] According to this configuration, by making the circumferential groove 60 symmetrical, the groove can be easily machined into the casing 26 .

[0053] [First and second modified examples of the first embodiment] Next, a slewing device for a construction machine according to a first modified example of the first embodiment will be described with reference to Figs. 7 and 8. Fig. 7 is a schematic perspective view showing a circumferential groove of a casing of a reduction gear device in a slewing device for a construction machine according to a first modified example of the first embodiment. Fig. 8 is an enlarged cross-sectional view showing the structure of a circumferential groove at the position where a sensor unit is arranged in the slewing device for a construction machine according to the first modified example of the first embodiment shown in Fig. 7. In Figs. 7 and 8, the same reference numerals as those in Figs. 1 to 6 denote similar parts, and therefore detailed description thereof will be omitted.

[0054] The slewing device for a construction machine according to a first modified example of the first embodiment shown in Figures 7 and 8 differs from the first embodiment in that the surfaces (bottom surface 60a and both side surfaces) forming the circumferential groove 60A in the lower case 41A of the reduction gear 22 are oil-repellent treated, and the surfaces forming a recess 64A provided at a second position 602 (deepest part) of the circumferential groove 60A are oil-repellent treated. Other configurations of the first modified example of the first embodiment are similar to those of the first embodiment.

[0055] 7 and 8, the oil-repellent treated areas of the circumferential groove 60A and the recessed portion 64A are shown by patterns. The oil-repellent treatment is, for example, a method of applying a fluorine-based silane coupling agent to the surfaces of the circumferential groove 60A (bottom surface 60a and both side surfaces) and the surfaces of the recessed portion 64A and then drying the agent. The agent is not particularly limited as long as it is possible to impart an oil-repellent function to the surfaces of the circumferential groove 60A and the recessed portion 64A. By making the surface of the circumferential groove 60A oil-repellent, foreign matter that has settled in the circumferential groove 60 can easily slide down to the deepest part of the second position 602.

[0056] Next, a slewing device for a construction machine according to a second modified example of the first embodiment will be described with reference to Figs. 9 and 10. Fig. 9 is a schematic cross-sectional view showing a circumferential groove of a casing of a reduction gear device in a slewing device for a construction machine according to a second modified example of the first embodiment. Fig. 10 is an enlarged cross-sectional view showing the structure of a circumferential groove at the position where a sensor unit is arranged in the slewing device for a construction machine according to the second modified example of the first embodiment shown in Fig. 9. In Figs. 9 and 10, the same reference numerals as those in Figs. 1 to 8 denote similar parts, and detailed descriptions thereof will be omitted.

[0057] The slewing device for a construction machine according to a second modified example of the first embodiment shown in Figures 9 and 10 differs from the first embodiment in that an oil-repellent resin member 65 is provided on the surfaces (bottom surface 60a and both side surfaces) that form the circumferential groove 60 in the lower case 41B of the reduction gear 22, and that an oil-repellent resin member 66 is provided on the surfaces that form a recess 64 provided at a second position 602 (deepest part) of the circumferential groove 60. Other configurations of the second modified example of the first embodiment are similar to those of the first embodiment.

[0058] In Fig. 9 and Fig. 10, the oil-repellent resin members 65, 66 are indicated by thicker lines than the other lines. The oil-repellent resin members 65, 66 are, for example, polytetrafluoroethylene resin materials molded into a shape corresponding to the circumferential groove 60. The resin member 65 is fixed to the circumferential groove 60 by, for example, bolts. The resin material of the resin members 65, 66 is not particularly limited as long as it is an oil-repellent material. The method of fixing the resin members 65, 66 to the circumferential groove 60 is not particularly limited, and a method of pasting is also possible. By covering the surface of the circumferential groove 60 with the oil-repellent resin members 65, 66, foreign matter that has settled in the circumferential groove 60 can easily slide down to the second position 602, which is the deepest part.

[0059] According to the first and second modified examples of the first embodiment described above, similarly to the first embodiment described above, the circumferential grooves 60, 60A that open upward and have a depth direction downward are provided on the inner wall surface 45a of the casing 26, so that most of the foreign matter generated in the planetary gear mechanism 24 (gear mechanism) can be settled in any of the circumferential grooves 60, 60A. Furthermore, by inclining the bottom surfaces 60a of the circumferential grooves 60, 60A from the shallowest part to the deepest part, the foreign matter that has settled in any of the circumferential grooves 60, 60A can be accumulated in the deepest part of the circumferential grooves 60, 60A. Since the sensor 71 detects the foreign matter accumulated in the deepest part of the circumferential grooves 60, 60A, the amount of foreign matter generated in the reduction gear device 22 (gear device) can be accurately grasped.

[0060] In the first and second modified examples, the circumferential groove 60A has a surface that has been subjected to an oil-repellent treatment, or an oil-repellent resin member 65 is disposed on the surface of the circumferential groove 60A.

[0061] According to this configuration, foreign matter that has settled in the circumferential grooves 60, 60A can slide down to the deepest part more easily. This allows foreign matter to be reliably accumulated in the deepest part of the circumferential grooves 60, 60A, improving the accuracy of diagnosing abnormalities in the swivel device 7 and determining when maintenance should be performed.

[0062] [Second embodiment] Next, a slewing device for a construction machine according to a second embodiment of the present invention will be described with reference to Figs. 11 and 12. Fig. 11 is a schematic cross-sectional view showing a circumferential groove of a casing of a reduction gear device in a slewing device for a construction machine according to the second embodiment. Fig. 12 is an enlarged cross-sectional view showing the structure of a circumferential groove at the position where a sensor unit is arranged in the slewing device for a construction machine according to the second embodiment shown in Fig. 11. In Figs. 11 and 12, the same reference numerals as those in Figs. 1 to 10 denote similar parts, and detailed descriptions thereof will be omitted.

[0063] The swing device for a construction machine according to the second embodiment shown in Figures 11 and 12 differs from the first embodiment in that the lower case 41C of the reduction gear 22 does not include a recess 64 (see Figures 3 to 6) provided in the deepest part of the circumferential groove 60, and the sensor 71 is disposed so that the sensor surface 71a faces the bottom surface 60a of the second position 602 (deepest part) of the circumferential groove 60, rather than the bottom surface 64a of the recess 64. Other configurations of the second embodiment are similar to those of the first embodiment.

[0064] The sensor 71 is disposed at a second position 602 corresponding to the deepest part of the circumferential groove 60, and detects the height (amount of accumulation) of foreign matter accumulated on the bottom surface 60a of the deepest part of the circumferential groove 60. The deepest part of the circumferential groove 60, which is the detection position of the sensor 71, has a certain depth relative to the step surface 48a on which the circumferential groove 60 is formed. For this reason, the effect of the flow of the lubricating oil on the deepest part of the circumferential groove 60 is relatively small, and foreign matter accumulated on the bottom surface 60a of the deepest part of the circumferential groove 60 is unlikely to be diffused outside the circumferential groove 60 by the flow of the lubricating oil.

[0065] In this manner, in the present embodiment, the recess 64 is not provided in the deepest portion of the circumferential groove 60 in the lower case 41C, and the sensor 71 is disposed at a position corresponding to the bottom surface 60a of the deepest portion of the circumferential groove 60. With this configuration, it is possible to reduce the number of steps required to process the recess 64 in the lower case 41C. According to the second embodiment described above, similarly to the first embodiment described above, by providing the circumferential groove 60, which is open upward and has a depth direction downward, on the inner wall surface 45a of the casing 26, it is possible to settle most of the foreign matter generated in the planetary gear mechanism 24 (gear mechanism) at any position in the circumferential groove 60. Furthermore, by inclining the bottom surface 60a of the circumferential groove 60 from the shallowest part to the deepest part, it is possible to accumulate the foreign matter that has settled at any position in the circumferential groove 60 at the deepest part of the circumferential groove 60. Since the sensor 71 detects the foreign matter accumulated at the deepest part of the circumferential groove 60, it is possible to accurately grasp the amount of foreign matter generated in the gear device 22.

[0066] [Third embodiment] Next, a slewing device for a construction machine according to a third embodiment of the present invention will be described with reference to Fig. 13. Fig. 13 is a vertical cross-sectional view showing a slewing device for a construction machine according to the third embodiment. In Fig. 13, the same reference numerals as those in Figs. 1 to 12 denote similar parts, and therefore detailed description thereof will be omitted.

[0067] The swing device for a construction machine according to the third embodiment shown in Fig. 13 differs from the first embodiment in that the reduction gear 22D does not include a shielding plate 56 (see Fig. 2) that shields the upper side of the upper bearing 28. Other configurations of the third embodiment are similar to those of the first embodiment.

[0068] In the present embodiment, the absence of the shielding plate 56 causes some of the wear powder to enter the upper bearing 28. However, most of the wear powder is swept toward the circumferential groove 60 located radially outward by the centrifugal force generated by the swirling flow of the lubricating oil, and settles within the circumferential groove 60. As a result, it is possible to accumulate most of the foreign matter generated within the reduction gear 22D within the circumferential groove 60, achieving an effect similar to that of the configuration of the first embodiment, while also reducing the number of parts by the amount of the shielding plate 56.

[0069] According to the third embodiment described above, similarly to the first embodiment described above, by providing the circumferential groove 60, which opens upward and has a depth direction downward, on the inner wall surface 45a of the casing 26, it is possible to settle most of the foreign matter generated in the planetary gear mechanism 24 (gear mechanism) at any position in the circumferential groove 60. Furthermore, by inclining the bottom surface 60a of the circumferential groove 60 from the shallowest part to the deepest part, it is possible to accumulate the foreign matter that has settled at any position in the circumferential groove 60 at the deepest part of the circumferential groove 60. Since the sensor 71 detects the foreign matter accumulated at the deepest part of the circumferential groove 60, it is possible to accurately grasp the amount of foreign matter generated in the reduction gear 22D (gear mechanism).

[0070] [Fourth embodiment] Next, a slewing gear for a construction machine according to a fourth embodiment of the present invention will be described with reference to Figs. 14 and 15. Fig. 14 is a schematic perspective view showing, in a see-through state, a circumferential groove of a casing of a reduction gear in a slewing gear for a construction machine according to the fourth embodiment. Fig. 15 is a schematic cross-sectional view showing a circumferential groove of a casing of a reduction gear in a slewing gear for a construction machine according to the fourth embodiment shown in Fig. 14. In Figs. 14 and 15, the same reference numerals as those in Figs. 1 to 13 denote similar parts, and detailed descriptions thereof will be omitted.

[0071] The swing gear for a construction machine according to the fourth embodiment shown in Figures 14 and 15 differs from the first embodiment in that the circumferential groove 60E formed in the lower case 41E of the reduction gear 22 is configured as a spiral groove rather than an annular groove. Other configurations of the fourth embodiment are similar to those of the first embodiment.

[0072] Specifically, a circumferential groove 60E formed in an annular stepped surface 48a (peripheral wall 45) of the lower case 41E is formed so that a first position 601 in the circumferential direction of the annular stepped surface 48a is the shallowest portion, and a second position 602 adjacent to the first position 601 in the circumferential direction (to the left of the first position 601 in Figs. 14 and 15) is the deepest portion. As shown in Fig. 14, the circumferential groove 60E has a bottom surface 60a that is inclined so as to gradually become deeper in the clockwise direction in the figure from the first position 601 (shallowest portion) to the second position 602 (deepest portion). As shown in Figures 14 and 15, the circumferential groove 60E is formed such that the bottom surface 60a at the first position 601, which is the shallowest part, and the bottom surface 60a at the second position 602, which is the deepest part, are not continuous but are discontinuous, and the bottom surface 60a at the first position 601 and the bottom surface 60a at the second position 602 are connected by a vertical surface 60c.

[0073] In this embodiment, most of the foreign matter such as wear powder generated by meshing of the planetary gear mechanism 24 settles at some position in the circumferential groove 60E, as in the first embodiment. The wear powder that settles in the circumferential groove 60E slides down along the inclined bottom surface 60a to the second position 602 at the deepest part, even though the circumferential groove 60E is a spiral groove. As a result, most of the wear powder accumulates in the deepest part of the spiral circumferential groove 60E. Therefore, by arranging the sensor 71 at a position corresponding to the deepest part of the spiral circumferential groove 60E, it is possible to accurately grasp the amount of foreign matter generated in the reduction gear 22.

[0074] According to the fourth embodiment described above, similarly to the first embodiment described above, by providing the circumferential groove 60E, which opens upward and has a depth direction downward, on the inner wall surface 45a of the casing 26, it is possible to settle most of the foreign matter generated in the planetary gear mechanism 24 (gear mechanism) at any position of the circumferential groove 60E. Furthermore, by inclining the bottom surface 60a of the circumferential groove 60E from the shallowest part to the deepest part, it is possible to accumulate the foreign matter that has settled at any position of the circumferential groove 60E at the deepest part of the circumferential groove 60E. Since the sensor 71 detects the foreign matter accumulated at the deepest part of the circumferential groove 60, it is possible to accurately grasp the amount of foreign matter generated in the reduction gear 22 (gear mechanism).

[0075] In the present embodiment, the circumferential groove 60E formed in the lower case 41E of the casing 26 of the reduction gear 22 is configured as a spiral groove in which a first position 601 at the shallowest part and a second position 602 at the deepest part are adjacent to each other. With this configuration, a vertical surface 60c standing upright is formed at the boundary between the adjacent shallowest and deepest parts, so that the vertical surface 60c of the circumferential groove 60E can prevent foreign matter accumulated in the deepest part of the circumferential groove 60E from being diffused by the flow of lubricating oil.

[0076] [Fifth embodiment] Next, a slewing device of a construction machine according to a fifth embodiment of the present invention will be described with reference to Figs. 16 to 18. Fig. 16 is a vertical cross-sectional view showing the slewing device of a construction machine according to the fifth embodiment. Fig. 17 is a schematic cross-sectional view showing the positional relationship of a sensor unit and a valve mechanism in the slewing device of a construction machine according to the fifth embodiment shown in Fig. 16. Fig. 18 is an explanatory view showing the operation and action of the valve mechanism in the slewing device of a construction machine according to the fifth embodiment shown in Fig. 17. In Figs. 16 to 18, the same reference numerals as those in Figs. 1 to 15 denote similar parts, and detailed description thereof will be omitted.

[0077] The swing device 7 for a construction machine according to the fifth embodiment shown in Fig. 16 differs from the first embodiment in that a communication hole 67 is provided in the lower case 41F of the reduction gear 22F, which connects the deepest part of the circumferential groove 60 with the drain hole 49, and that a valve device 80 capable of opening and closing the communication hole 67 is disposed in the lower case 41F. Other configurations of the fifth embodiment are similar to those of the first embodiment.

[0078] Specifically, the circumferential groove 60 formed in the lower case 41F of the casing 26 is configured so that the second position 602 (deepest part) is located directly above the drain hole 49 of the bulging part 48 of the lower case 41F. The communication hole 67 extends in the vertical direction in the bulging part 48 (thick part) of the lower case 41F, with one side (upper side) opening at the deepest part of the circumferential groove 60 and the other side (lower side) opening to the drain hole 49.

[0079] 17, a valve element 81 of a valve device 80 that opens and closes the communication hole 67 is disposed in a position in the communication hole 67 near the bottom surface 60a of the deepest part of the circumferential groove 60. The valve element 81 is, for example, a flat plate-like member that can close the communication hole 67, and is a portion that serves as a deposition area where foreign matter that has slid down to the deepest part of the circumferential groove 60 further flows down the communication hole 67 and deposits there. The valve element 81 is installed at a position within a range that can be detected by the sensor 71 that is disposed at a position corresponding to the second position 602 at the deepest part of the circumferential groove 60.

[0080] The valve device 80 has an operating member 82 that operates the valve body 81 so as to be movable in the radial direction relative to the lower case 41F. The operating member 82 is composed of an operating portion 83 that an operator operates to move the valve body 81, and a support portion 84 that extends from the operating portion 83 and is connected to the valve body 81. A seal member 85 (e.g., an O-ring) is attached to the outer circumferential surface of the support portion 84. The seal member 85 prevents leakage of lubricating oil in the casing 26 from a gap between the operating member 82 of the valve body 81 and the lower case 41F. By drawing out the operating portion 83 of the operating member 82 radially outward from the lower case 41F, the valve body 81 is displaced from a closed position where the communication hole 67 is blocked to an open position where the blockage of the communication hole 67 is released. A scraping member 86 that is in contact with the upper surface of the valve body 81 is disposed at a radially outer position of the communication hole 67 of the lower case 41F. The scraping member 86 has a function of scraping off foreign matter P that has accumulated on the valve body 81 when the valve body 81 is displaced to the open position.

[0081] In this embodiment, most of the foreign matter such as wear powder generated by meshing of the planetary gear mechanism 24 shown in FIG. 16 settles at some position in the circumferential groove 60, as in the first embodiment. The wear powder that settles in the circumferential groove 60 slides down along the inclined bottom surface 60a of the circumferential groove 60 to the second position 602 at the deepest part. The foreign matter that moves to the second position 602 at the deepest part of the circumferential groove 60 further settles in the communication hole 67 and accumulates on the flat valve body 81 that blocks the communication hole 67, as shown in FIG. 17. As a result, most of the wear powder is accumulated on the valve body 81 in the communication hole 67. Therefore, by arranging the sensor 71 at a position corresponding to the communication hole 67 (the deepest part of the circumferential groove 60), it is possible to accurately detect the amount of foreign matter generated in the reduction gear 22.

[0082] In this embodiment, the communication hole 67 is opened by displacing the valve body 81 radially outward of the lower case 41F with an operating member 82 shown in FIG. 17. At this time, as shown in FIG. 18, foreign matter P accumulated on the valve body 81 is scraped off by a scraping member 86 that contacts the upper surface of the valve body 81. As a result, the foreign matter P accumulated on the valve body 81 moves through the communication hole 67 to the drain hole 49 shown in FIG. 16. The foreign matter that has moved into the drain hole 49 can be discharged to the outside of the casing 26 by opening the drain plug 53.

[0083] According to the fifth embodiment described above, similarly to the first embodiment described above, by providing the circumferential groove 60 that opens upward and has a depth direction downward on the inner wall surface 45a of the lower case 41F, it is possible to settle most of the foreign matter generated in the planetary gear mechanism 24 (gear mechanism) at any position in the circumferential groove 60. Furthermore, by inclining the bottom surface 60a of the circumferential groove 60 from the shallowest part to the deepest part, it is possible to accumulate the foreign matter that has settled at any position in the circumferential groove 60 at the deepest part of the circumferential groove 60. Since the sensor 71 detects the foreign matter accumulated at the deepest part of the circumferential groove 60, it is possible to accurately grasp the amount of foreign matter generated in the reduction gear device 22 (gear device).

[0084] In the slewing device 7 according to this embodiment, the casing 26 (lower case 41F) of the reduction gear 22 (gear device) has a drain hole 49 that is provided below the second position 602 of the circumferential groove 60 and extends from the inner wall surface 45a to the outer wall surface 45b, and a communication hole 67 that communicates between the deepest part of the circumferential groove 60 and the drain hole 49. The reduction gear 22 (gear device) has a flat valve body 81 that opens and closes the communication hole 67.

[0085] According to this configuration, by appropriately displacing the valve body 81 to the open position, foreign matter P generated within the reduction gear 22 (gear device) can be easily discharged to the outside of the casing 26, thereby improving the maintainability of the slewing device 7.

[0086] [Sixth embodiment] Next, a construction machine according to a sixth embodiment of the present invention will be described with reference to Figures 19 to 21. In Figures 19 to 21, the same reference numerals as those in Figures 1 to 18 denote similar parts, and detailed descriptions thereof will be omitted. Figure 19 is a configuration diagram showing a network of multiple computers that utilizes detection data from sensors in a slewing device of a construction machine according to the sixth embodiment.

[0087] In this embodiment, as shown in Fig. 19, in addition to the controller 8, a server computer 101, a service computer 111, and an administrator computer 112 are used. The arrows in Fig. 19 indicate the flow of data. Each of the computers 101, 111, and 112 includes a processor (e.g., a CPU) and a storage device (e.g., a memory) like the controller 8, and is configured so that the processor can execute various processes based on programs stored in the storage device.

[0088] The detection data collected by the controller 8 of the hydraulic excavator 1 from the sensor 71 is transmitted to a server computer 101 (hereinafter referred to as the server) via a wireless communication device 9 or the like. The server 101 then diagnoses the lubricating oil in the slewing device 7 based on the data, and transmits the diagnosis results to a service computer 111 or an administrator computer 112.

[0089] Here, the flow of diagnosis of the slewing device 7 performed by the server 101 will be described with reference to Fig. 20. Fig. 20 is a flow chart showing an example of the procedure of diagnosis processing of the lubricating oil of the slewing device performed by the server of the network shown in Fig. 19.

[0090] The flow shown in FIG. 20 is a repetitive process, in which the process starts after the hydraulic excavator 1 starts operating, and data detected by the sensor 71 is transmitted to the server 101 at predetermined time intervals set by a timer or the like, for example, every hour, and the server 101 performs diagnostic processing based on the data.

[0091] First, the server 101 (processor (same for the following processes)) acquires detection data from the sensor 71 of the turning device 7 (step S10).

[0092] Next, the server 101 determines whether the height of the foreign matter accumulated in the deepest part of the circumferential groove 60 obtained based on the detection data of the sensor 71 exceeds a threshold value (step S20). An example of foreign matter measurement by the sensor 71 is shown in FIG. 21. FIG. 21 is a diagram showing an example of change in foreign matter height (accumulation amount) with respect to operation time in a swing device of a construction machine according to the sixth embodiment. In the example shown in FIG. 21, foreign matter height H tends to increase as operation time T increases. Furthermore, the slope of the height changes significantly at a certain operation time point.

[0093] In this embodiment, if the foreign object height H exceeds the threshold value, the server 101 advances the process to step S30. On the other hand, if the foreign object height H is equal to or less than the threshold value, the server 101 determines that the state of the swing device 7 is normal (the planetary gear mechanism 24 is not damaged), and advances the process to step S40.

[0094] In step S30, the server 101 notifies the service computer 111 and the administrator computer 112 that an abnormality has occurred in the swing device 7. This causes the operation of the hydraulic excavator 1 to be stopped. The swing device 7 is disassembled to check the condition of the gears.

[0095] On the other hand, in step S40, the server 101 stores the measurement value (height H) of the foreign object, and waits until the next processing start timing.

[0096] As described above, by performing an abnormality diagnosis using the server 101, an abnormality in the swing gear 7 can be detected at an early stage, and an increase in downtime of the hydraulic excavator 1 can be suppressed.

[0097] The process according to the flow of Fig. 21 can also be executed by the controller 8. The process according to the flow of Fig. 21 can also be executed by a microcomputer installed in the sensor 71.

[0098] [Other embodiments] The present invention is not limited to the above-mentioned first to sixth embodiments and their modified examples, but includes various modified examples. The above-mentioned embodiments have been described in detail to explain the present invention in an easy-to-understand manner, and are not necessarily limited to those having all the configurations described. For example, it is possible to replace a part of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of one embodiment. It is also possible to add, delete, or replace a part of the configuration of each embodiment with another configuration.

[0099] For example, in the above-described embodiment, an example has been shown in which the gear mechanism of the reduction gear device 22 is a planetary gear mechanism. However, the gear mechanism of the reduction gear device 22 can be configured with a mechanism other than a planetary gear mechanism as long as it is capable of transmitting the rotational driving force after reducing the speed.

[0100] In the above-described first embodiment and its modified example, the circumferential grooves 60, 60A are formed such that the first position, which is the shallowest part, and the second position, which is the deepest part, are located at positions of 180°. However, the positions of the shallowest part and the deepest part of the circumferential grooves 60, 60A are arbitrary as long as the first position, which is the shallowest part, and the second position, which is the deepest part, are different positions.

[0101] In the fourth embodiment described above, an example of a configuration in which there is no recess at the second position, which is the deepest part of the circumferential groove 60E, has been shown. However, similarly to the first embodiment, a configuration in which a recess is provided at the deepest part of the circumferential groove 60E is also possible.

[0102] In addition, the components related to the controller 8 and server 101 in the above-mentioned embodiment, as well as the functions and execution processes of the components, may be realized in part or in whole by hardware (for example, by designing the logic for executing each function in an integrated circuit). [Explanation of symbols]

[0103] 1...hydraulic excavator (construction machine), 6...slewing ring, 7...slewing device, 21...slewing motor (slewing drive source), 22, 22D, 22F...reduction device (gear device), 24...planetary gear mechanism (gear mechanism), 25...output shaft, 26...casing, 28...upper bearing, 45a...inner wall surface, 45b...outer wall surface, 49...drain hole, 56...shielding plate, 56a...tip, 60, 60A, 60E...circumferential groove, 60a...bottom surface, 61...first groove portion, 61a...bottom surface, 62...second groove portion, 62a...bottom surface, 64...recess, 65...resin member, 67...communicating hole, 71...sensor, 81...valve body, 601...first position, 602...second position

Claims

1. a rotation drive source that generates a rotational drive force for rotating a rotating body of the construction machine; a gear device including a gear mechanism that transmits the rotational driving force of the slewing drive source, an output shaft that outputs the rotational driving force transmitted to the gear mechanism to a slewing wheel of the construction machine, and a casing that houses the gear mechanism and the output shaft and stores lubricating oil that lubricates the gear mechanism; a sensor for detecting foreign matter accumulated in the casing; In a slewing device for a construction machine, the gear device is arranged so that the rotation axis of the gear mechanism and the output shaft extends in the up-down direction of the slewing body, the casing has an inner wall surface, at a position below an engagement portion of the gear mechanism, and a circumferential groove extending around the entire circumferential direction of the inner wall surface, The circumferential groove is a groove that opens upward in the up-down direction and has a depth direction in the downward direction, the circumferential groove has a shallowest portion at a first position in the circumferential direction and a deepest portion at a second position different from the first position in the circumferential direction, and has a bottom surface that is an inclined surface that gradually becomes deeper from the first position toward the second position, The sensor is disposed at a position of the circumferential groove corresponding to the second position. A turning device for a construction machine.

2. The construction machine swing device according to claim 1, The circumferential groove is an annular groove in which a bottom surface of a first groove portion extending from the first position to one side in the circumferential direction to the second position and a bottom surface of a second groove portion extending from the first position to the other side in the circumferential direction to the second position are connected without a step. A turning device for a construction machine.

3. The construction machine swing device according to claim 1, The circumferential groove is a spiral groove in which the first position and the second position are adjacent to each other. A turning device for a construction machine.

4. The construction machine swing device according to claim 1, The casing comprises: a drain hole provided below the second position of the circumferential groove and extending from the inner wall surface to the outer wall surface; a communication hole that communicates the deepest portion of the circumferential groove with the drain hole, The gear device has a flat valve body capable of opening and closing the communication hole. A turning device for a construction machine.

5. The construction machine swing device according to claim 1, The circumferential groove has a surface that has been subjected to an oil repellent treatment. Or, An oil-repellent resin member is disposed on the surface of the circumferential groove. A turning device for a construction machine.

6. The construction machine swing device according to claim 1, The casing has a recess at the second position of the circumferential groove that is recessed downward from the bottom surface of the circumferential groove. A turning device for a construction machine.

7. The construction machine swing device according to claim 1, The gear device comprises: a bearing fixed to the casing at a position radially inward of the circumferential groove and configured to rotatably support the output shaft; an annular shielding plate located above and radially inward of the circumferential groove and installed to shield an upper side of the bearing, The shielding plate is inclined downward from a base end on the radial inside to a tip end on the radial outside. A turning device for a construction machine.

8. The turning device for a construction machine according to claim 2, The circumferential groove is a groove that is line-symmetrical with respect to a line segment connecting the first position and the second position. A turning device for a construction machine.

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