Lower running body of construction machine

Abstract

To provide a lower running body of a construction machine that can extend the life of a lower roller and a crawler belt by suppressing wear at a contact portion between the lower roller and the crawler belt.SOLUTION: The lower running body of a construction machine is provided with a rotational speed sensor 22 that detects the rotational speed of a lower roller 21 that is provided on the underside of a track side frame 13 and guides a crawler belt 17 between a drive wheel 15 and an idler wheel 16, a lubricant supply device 23 that supplies lubricant toward a contact portion 32 between the crawler belt 17 and the lower roller 21, and a supply control device 31 that controls the supply of the lubricant from the lubricant supply device 23 toward the contact portion 32 when the rotational speed sensor 22 detects that the rotation of the lower roller 21 has stopped while a lower running body 11 is running.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to an undercarriage of a construction machine that is provided with lower rollers that guide a crawler belt between a drive wheel and an idler wheel. [Background technology]

[0002] A hydraulic excavator, a typical example of construction machinery, comprises a self-propelled lower running body, an upper rotating body rotatably mounted on the lower running body, and a working device rotatably mounted on the front of the upper rotating body.

[0003] The lower running body includes a track center frame, a pair of track side frames arranged on either side of the track center frame, a drive wheel provided at a first end in the longitudinal direction of the track side frame, an idler wheel provided at a second end in the longitudinal direction of the track side frame, a crawler belt wound between the drive wheel and the idler wheel, and a lower roller provided below the track side frame to guide the crawler belt between the drive wheel and the idler wheel (Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2003-252258 Summary of the Invention [Problem to be solved by the invention]

[0005] In the invention of Patent Document 1, the lower rollers rotate in contact with the inner surface of the crawler belt, thereby guiding the crawler belt. Therefore, a large load due to the weight of the hydraulic excavator acts on the contact points between the lower rollers and the crawler belt. Furthermore, when the undercarriage of the hydraulic excavator travels over uneven ground, the crawler belt may follow the unevenness of the ground and bend like a wave, causing some of the lower rollers to float above the crawler belt and stop rotating. In this case, the lower rollers will rotate again by coming into contact with the crawler belt.

[0006] When the lower roller comes into contact with the crawler belt, a large load is suddenly applied to the contact area between the lower roller and the crawler belt, which can cause strong friction and wear at the contact area, resulting in a problem of shortening the lifespan of the lower roller and the crawler belt.

[0007] An object of one embodiment of the present invention is to provide a lower running body for a construction machine that can extend the life of the lower rollers and the tracks by suppressing wear at the contact points between the lower rollers and the tracks. [Means for solving the problem]

[0008] One embodiment of the present invention relates to a lower running body of a construction machine comprising a track center frame, a pair of track side frames arranged on either side of the track center frame, a drive wheel provided at a first longitudinal end of the track side frame, an idler wheel provided at a second longitudinal end of the track side frame, a crawler belt wound between the drive wheel and the idler wheel, and a lower roller provided below the track side frame and guiding the crawler belt between the drive wheel and the idler wheel, the lower running body comprising: a rotational speed sensor that detects the rotational speed of the lower roller; a lubricant supply device that supplies lubricant toward the contact portion between the crawler belt and the lower roller; and a supply control device that controls the supply of lubricant from the lubricant supply device toward the contact portion when the rotational speed sensor detects that the rotation of the lower roller has stopped during running. [Effects of the Invention]

[0009] According to the present invention, wear at the contact portion between the lower roller and the crawler belt can be suppressed, and the life of the lower roller and the crawler belt can be extended. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a left side view showing a hydraulic excavator equipped with a lower traveling body according to a first embodiment of the present invention. [Figure 2]FIG. 2 is a left side view showing the lower traveling body in FIG. [Figure 3] FIG. 2 is a left side view showing the main parts of the lower traveling body together with a rotation speed sensor, a lubricant supply device, and a supply control device. [Figure 4] 4 is a cross-sectional view of the rotational speed sensor mounting structure for the lower traveling body, as viewed from the direction of arrows IV-IV in FIG. 3. [Figure 5] 4 is a cross-sectional view of the shapes of an outer nozzle and an inner nozzle of the lubricant supplying device according to the first embodiment, as viewed in the direction of arrows VV in FIG. 3. FIG. [Figure 6] FIG. 4 is a left side view of the lower traveling body showing a state in which the lower roller has been separated from the crawler belt. [Figure 7] FIG. 10 is a left side view showing a lubricant supply device according to a second embodiment of the present invention, together with essential parts of a lower traveling body, a rotational speed sensor, and a supply control device. [Figure 8] 8 is a cross-sectional view of the shapes of an outer nozzle and an inner nozzle of the lubricant supplying device according to the second embodiment, as viewed in the direction of arrows VIII-VIII in FIG. 7. DETAILED DESCRIPTION OF THE INVENTION

[0011] The following describes in detail the undercarriage of a hydraulic excavator as a representative example of the undercarriage of a construction machine according to an embodiment of the present invention, with reference to the accompanying drawings. Note that the front and rear sides of the undercarriage change depending on the rotation position of the upper rotating body, but in this embodiment, the side where the idler wheels are provided is referred to as the front side, and the side where the drive wheels are provided is referred to as the rear side.

[0012] Figures 1 to 6 show a first embodiment of the present invention. In Figure 1, a hydraulic excavator 1 includes a lower traveling structure 11 (described below), an upper rotating structure 2 rotatably mounted on the lower traveling structure 11, and a work device 3 rotatably provided at the front of the upper rotating structure 2 for performing work such as excavating earth and sand. A cab 4 for an operator is provided on the front left side of the upper rotating structure 2.

[0013] The upper rotating body 2 is also provided with a prime mover consisting of an engine, an electric motor, etc., a hydraulic pump driven by the prime mover, and a control valve (none of which are shown) that supplies hydraulic oil (pressurized oil) discharged from the hydraulic pump to various hydraulic actuators.

[0014] Next, the configuration of the lower traveling structure 11 of the hydraulic excavator 1 will be described in detail.

[0015] The crawler-type undercarriage 11 travels not only on flat ground but also on uneven ground, etc. As shown in Figures 1 and 2, the undercarriage 11 includes a track center frame 12, left and right track side frames 13, drive wheels 15, idler wheels 16, crawler belts 17, upper rollers 20, lower rollers 21, a rotational speed sensor 22, a lubricant supply device 23, and a supply control device 31, which will be described later.

[0016] The truck center frame 12 is located at the center of the lower traveling body 11. The upper rotating body 2 is rotatably attached to the upper side of the truck center frame 12. A center joint (not shown) consisting of a swivel joint is provided at the center of rotation of the truck center frame 12. This center joint allows the upper rotating body 2 to rotate on the lower traveling body 11, while also circulating hydraulic oil (pressurized oil) between the upper rotating body 2 and the lower traveling body 11 and conducting electricity (power supply, signals).

[0017] The track side frames 13 are provided on both the left and right sides of the track center frame 12, extending in the front-rear direction. The pair of track side frames 13 are arranged symmetrically on both the left and right sides of the track center frame 12. The track side frames 13 are formed as rectangular cylinders or inverted U-shaped bodies extending in the front-rear direction.

[0018] Upper rollers 20, which will be described later, are provided on the upper surface 13A of the track side frame 13. Lower rollers 21, which will be described later, are provided on the lower surface 13B of the track side frame 13. Meanwhile, an inner pipe 25C of a supply pipe 25, which will be described later, is attached to an inner surface 13C of the track side frame 13 in the left-right direction. Furthermore, an outer pipe 25B of the supply pipe 25, which will be described later, and a signal line 22B of a rotational speed sensor 22 are attached to an outer surface 13D of the track side frame 13 in the left-right direction. The inner surface 13C of the track side frame 13 is attached to the track center frame 12.

[0019] Pairs of support brackets 14 are integrally provided on the undersides 13B of the track side frames 13, spaced apart in the left-right direction (vehicle width direction). The support brackets 14 are provided in multiple pairs, for example, eight pairs (16 in total), spaced apart in the front-rear direction. Although the support brackets 14 are illustrated as being integral with the track side frames 13, they may be provided separately from the track side frames 13 and attached using bolts.

[0020] The drive wheels 15 are provided at the rear ends, which are first ends in the longitudinal direction of the track side frames 13. The drive wheels 15 are driven to rotate by a traveling device (not shown) including a hydraulic motor, a reducer, etc. as a power source. The drive wheels 15 cause the crawler belts 17 to move in an orbital motion by engaging engagement protrusions 18B of track links 18 constituting the crawler belts 17, which will be described later, with engagement recesses (not shown) arranged in a row around the periphery of the drive wheels 15. On the other hand, the idler wheels 16 are provided at the front ends, which are second ends in the longitudinal direction of the track side frames 13.

[0021] The crawler belt 17 is wound around the drive wheel 15 and the idler wheel 16. The crawler belt 17 is configured in an endless loop shape by a plurality of track links 18 arranged consecutively in the fore-and-aft direction and a plurality of connecting pins 19 that rotatably connect adjacent track links 18. The plurality of track links 18 have inner surfaces 18A that come into contact with the drive wheel 15, the idler wheel 16, the upper roller 20, and the lower roller 21. An engaging protrusion 18B is protruded from the middle position of the inner surface 18A of the track link 18. This engaging protrusion 18B engages with engaging recesses arranged in a row around the drive wheel 15.

[0022] The crawler belt 17 moves in an orbit between the drive wheel 15 and the idler wheel 16 by sequentially engaging the engagement protrusions 18B of the plurality of track links 18 with the engagement recesses of the rotating drive wheel 15. The crawler belt 17 also rotates the idler wheel 16 by frictionally contacting the inner surface 18A of the crawler belt 17 with the peripheral surface of the idler wheel 16.

[0023] That is, the plurality of track links 18 move linearly between the drive wheels 15 and the idler wheels 16 in the forward and backward direction of the hydraulic excavator 1. At this time, adjacent track links 18 are parallel (in a straight line). Furthermore, the plurality of track links 18 move in an arc along the outer circumferential surfaces of the drive wheels 15 and the idler wheels 16. At this time, the adjacent track links 18 rotate and bend around the connecting pins 19 so as to follow the drive wheels 15 and the idler wheels 16.

[0024] 4 and 5, the plurality of track links 18 constituting the crawler belt 17 have, for example, two pairs of first boss portions 18C (four in total) on the left and right at their front end edges, and second boss portions 18D (two in total) that fit between the pair of first boss portions 18C at their rear end edges. The second boss portion 18D of one adjacent track link 18 is inserted between the pair of first boss portions 18C of another track link 18. In this state, by inserting a connecting pin 19 into the boss portions 18C, 18D, the adjacent track links 18 are rotatably connected.

[0025] The upper rollers 20 are provided on the upper surfaces 13A of the track side frames 13. The upper rollers 20 support the crawler belt 17 from below and guide it in the longitudinal direction. For example, three upper rollers 20 are provided at intervals in the longitudinal direction. Each upper roller 20 includes a support member 20A attached to the upper surfaces 13A of the track side frames 13, and a roller portion 20B rotatably supported by the support member 20A with the left-right direction as its center line. The upper rollers 20 may be provided in one, two, or four or more locations.

[0026] The lower rollers 21 are provided on the lower surface 13B of the track side frame 13. The lower rollers 21 guide the crawler belt 17 between the drive wheels 15 and the idler wheels 16. The lower rollers 21 press the crawler belt 17 against the ground from above. A plurality of lower rollers 21, for example, eight lower rollers 21, are provided at intervals in the front-to-rear direction. The number of lower rollers 21 may be other than eight.

[0027] The lower roller 21 is composed of a roller pin 21A extending in the left-right direction and having both ends inserted into the left and right support brackets 14, two roller portions 21B rotatably supported by the roller pin 21A, and a spacer 21C located between the two roller portions 21B and provided around the roller pin 21A. The spacer 21C separates the two roller portions 21B so as to avoid the engaging protrusion 18B of the track link 18.

[0028] Roller portion 21B is formed as a thick disk or a short, thick cylinder. Roller portion 21B has circular side surfaces 21B1 facing each other in the thickness direction and a cylindrical circumferential surface 21B2 positioned around side surfaces 21B1. Circumferential surface 21B2 comes into frictional contact with inner surfaces 18A of track links 18 constituting crawler belt 17 at contact portions 32 (described below).

[0029] It is also possible to provide two roller portions and a spacer integrally and rotatably support them on the roller pin 21 A. Also, when two engaging protrusions are provided on the track link spaced apart on the left and right, it is also possible to provide only one roller portion.

[0030] There are provided eight rotation speed sensors 22, one for each lower roller 21. Each rotation speed sensor 22 detects the rotation speed of roller portion 21B of the corresponding lower roller 21. Each rotation speed sensor 22 detects in a non-contact manner whether roller portion 21B of a lower roller 21 is rotating, and outputs a detection signal to supply control device 31. Each rotation speed sensor 22 is screwed to support bracket 14 so that detection portion 22A is close to and faces side surface 21B1 of roller portion 21B.

[0031] In this embodiment, the rotation speed sensor 22 is attached to the support bracket 14 located on the outer side in the left-right direction, and the signal wire 22B extending from the rotation speed sensor 22 is routed along the outer surface 13D of the track side frame 13. However, the rotation speed sensor 22 can also be attached to the support bracket 14 located on the inner side in the left-right direction, and the signal wire 22B extending from the rotation speed sensor 22 can be routed along the inner surface 13C of the track side frame 13. The signal wire 22B can also be routed inside the track side frame 13. In this case, the signal wire 22B can be protected from obstacles and flying stones.

[0032] 3, the lubricant supply device 23 supplies lubricant toward a contact portion 32 between the crawler belt 17 and the lower roller 21. The lubricant supply device 23 is provided on the lower traveling body 11. The lubricant supply device 23 includes a lubricant tank 24, a supply pipe 25, a pump 26, a valve 28, an outer nozzle 29, an inner nozzle 30, and a supply control device 31, which will be described later.

[0033] The lubricant tank 24 is a container for storing lubricant. The lubricant tank 24 is attached to the track center frame 12 or the track side frame 13. In this case, the lubricant tank 24 is disposed in a position that is easily accessible from the outside so that the lubricant can be replenished.

[0034] Here, when steel parts are made of the same or similar materials, the lubricant is preferably made of a material different from the steel material, as it can prevent the promotion of adhesive wear due to affinity and reduce the amount of wear. Furthermore, the lubricant must have a molecular structure with an intermolecular force bonding structure that can intervene and reduce abrasive wear caused by friction between any two or more substances, even before adhesive wear occurs. For these reasons, lubricants that cause little environmental damage even if they fall into the soil, such as solid powders containing graphite, are used. However, there are no specific requirements as long as the lubricant recovery method and environmental conservation conditions are sufficient.

[0035] The supply pipe 25 extends from the lubricant tank 24 to the lower roller 21. The supply pipe 25 supplies the lubricant in the lubricant tank 24 to the outer nozzles 29 and the inner nozzles 30. The supply pipe 25 includes a common pipe 25A between the lubricant tank 24 and the valve 28, outer pipes 25B between the valve 28 and the eight outer nozzles 29, and inner pipes 25C (see FIG. 4) between the valve 28 and the eight inner nozzles 30.

[0036] The outer pipe 25B is provided below the outer surface 13D of the track side frame 13, extending in the front-rear direction. The inner pipe 25C is provided below the inner surface 13C of the track side frame 13, extending in the front-rear direction. The supply pipe 25 is formed using metal piping, hoses, or both. The supply pipe 25 can also be routed inside the track side frame 13. In this case, the supply pipe 25 can be protected from obstacles and flying stones.

[0037] The pump 26 is provided in the common pipe 25A of the supply pipe 25. The pump 26 pumps the lubricant in the lubricant tank 24, and is driven by a motor 27. For example, the pump 26 is always driven by the motor 27, so that the lubricant can be pumped out instantaneously.

[0038] Valve 28 is provided in supply pipe 25, located downstream of pump 26. Specifically, valve 28 is disposed between common pipe 25A and outer pipe 25B and inner pipe 25C. When valve 28 is opened under the control of supply control device 31, it supplies lubricant supplied through common pipe 25A to outer pipe 25B and inner pipe 25C. Valve 28 is, for example, an electromagnetic pilot type switching valve, and its pilot section 28A is electrically connected to supply control device 31.

[0039] The outer nozzles 29 serving as nozzles are provided downstream of the valve 28, i.e., connected to the outer conduit 25B of the supply conduit 25. Eight outer nozzles 29 are provided corresponding to the eight lower rollers 21 (the roller portions 21B located on the outer sides). The outer nozzles 29 discharge lubricant to the roller portions 21B located on the outer sides of the lower rollers 21. As shown in FIG. 5, the upstream side of each outer nozzle 29 is connected to the outer conduit 25B, and the downstream side extends obliquely inward from the outer surface 13D of the track side frame 13. The downstream tip of each outer nozzle 29 opens as a discharge port 29A above the outer roller portion 21B.

[0040] As a result, the outer nozzle 29 can supply lubricant supplied from the outer pipeline 25B to the upper position of the roller portion 21B opposite the inner surface 18A of the track link 18 that constitutes the crawler belt 17 by discharging the lubricant from the discharge port 29A.

[0041] The lubricant discharged to the upper position of the roller portion 21B moves downward due to the rotation of the roller portion 21B and gravity, and is supplied to the contact portion 32 between the circumferential surface 21B2 of the roller portion 21B and the inner surface 18A of the track link 18. This makes it possible to suppress wear at the contact portion 32 by the lubricant.

[0042] On the other hand, the inner nozzle 30 serving as a nozzle is provided downstream of the valve 28, i.e., connected to the inner pipe 25C of the supply pipe 25. Eight inner nozzles 30 (only one shown) are provided corresponding to the eight lower rollers 21 (the roller portions 21B located on the inside). The inner nozzles 30 discharge lubricant to the roller portions 21B located on the inside of the lower rollers 21. The upstream side of the inner nozzle 30 is connected to the inner pipe 25C, and the downstream side extends obliquely outward from the inner surface 13C of the track side frame 13. The downstream tip of the inner nozzle 30 opens as a discharge port 30A above the roller portion 21B located on the inside.

[0043] As a result, the inner nozzle 30 can supply lubricant supplied from the inner pipe 25C toward the upper position of the roller portion 21B opposite the inner surface 18A of the track link 18 that constitutes the crawler belt 17 by discharging the lubricant from the discharge port 30A.

[0044] The lubricant discharged to the upper position of the roller portion 21B moves downward due to the rotation of the roller portion 21B and gravity, and is supplied to the contact portion 32 between the circumferential surface 21B2 of the roller portion 21B and the inner surface 18A of the track link 18. This makes it possible to suppress wear at the contact portion 32 by the lubricant.

[0045] The supply control device 31 constitutes a control unit (CU) that controls the supply of lubricant. When the rotation speed sensor 22 detects that the roller portion 21B of any one of the eight lower rollers 21 has stopped rotating while the lower traveling body 11 is traveling, the supply control device 31 controls the supply of lubricant from the lubricant supply device 23 to the contact portion 32 between the crawler belt 17 and the lower roller 21. Furthermore, upon receiving a signal from the rotation speed sensor 22 indicating that the rotation of the lower roller 21 has stopped, the supply control device 31 controls the lubricant supply device 23 to automatically supply lubricant.

[0046] 6, when the undercarriage 11 travels over uneven ground, the crawler belt 17 may bend in response to the unevenness, causing some of the lower rollers 21 to lift off the crawler belt 17 and stop rotating. When this happens, the rotational speed sensor 22 outputs a signal to the supply control device 31 to stop the rotation of the lower rollers 21. When the signal to stop the rotation of the lower rollers 21 is input, the supply control device 31 outputs a control signal to the pilot section 28A of the valve 28 to open the valve 28.

[0047] On the other hand, when the lower roller 21 comes into contact with the crawler belt 17 and starts rotating again, the rotational speed sensor 22 outputs a rotation start signal for the lower roller 21 to the supply control device 31. When the rotation start signal for the lower roller 21 is input, the supply control device 31 outputs a control signal to the pilot part 28A of the valve 28 to close the valve 28.

[0048] In this way, the supply control device 31 can automatically start and stop supplying lubricant by opening and closing the valve 28 upon receiving a rotation stop signal and a rotation start signal for the lower roller 21 from the rotation speed sensor 22. Note that a lubricant supply switch may be provided in the cab 4, allowing the lubricant to be supplied manually when the rotation of the lower roller 21 stops.

[0049] The hydraulic excavator 1 according to this embodiment has the above-described configuration, and its operation will now be described.

[0050] The operator sits in the cab 4, starts the engine, and operates a lever and pedal device (not shown) for traveling, thereby causing the lower traveling body 11 to travel. On the other hand, the operator can operate a control lever device (not shown) for work, thereby causing the upper rotating body 2 to rotate, and the working device 3 to perform work such as excavating earth and sand.

[0051] Furthermore, when the lower running structure 11 travels over uneven ground, as shown in Fig. 6, the crawler belt 17 bends in response to the unevenness, causing the roller portions 21B of some of the lower rollers 21 to float above the inner surfaces 18A of the track links 18 that make up the crawler belt 17, and the rotation of the roller portions 21B stops. As the lower running structure 11 travels in this state, the bending of the crawler belt 17 changes, and the inner surfaces 18A of the track links 18 come into contact with the circumferential surfaces 21B2 of the roller portions 21B that were stopped. As a result, the roller portions 21B of the lower rollers 21 that were stopped begin to rotate again together with the crawler belt 17 due to frictional contact with the inner surfaces 18A of the track links 18.

[0052] When the stopped lower roller 21 comes into contact with the crawler belt 17, a large load due to the weight of the hydraulic excavator 1 acts all at once on the contact portion 32 between the lower roller 21 (the peripheral surface 21B2 of the roller portion 21B) and the crawler belt 17 (the inner surface 18A of the track link 18). Therefore, there is a risk that the contact portion 32 will rub strongly, causing wear on the lower roller 21 and the crawler belt 17.

[0053] However, according to this embodiment, the system is provided with a rotational speed sensor 22 provided below the track side frame 13, which detects the rotational speed of the lower roller 21 that guides the crawler belt 17 between the drive wheel 15 and the idler wheel 16; a lubricant supply device 23 that supplies lubricant toward the contact portion 32 between the crawler belt 17 and the lower roller 21; and a supply control device 31 that controls the supply of lubricant from the lubricant supply device 23 toward the contact portion 32 when the rotational speed sensor 22 detects that the rotation of the lower roller 21 has stopped while the lower running body 11 is running.

[0054] Therefore, when the rotational speed sensor 22 detects that the roller portion 21B of the lower roller 21 has stopped rotating while the lower traveling body 11 is traveling, the supply control device 31 can cause the lubricant supply device 23 to supply lubricant to the contact portion 32 between the crawler belt 17 and the lower roller 21. As a result, when the lower roller 21 comes into contact with the crawler belt 17 again, the lubricant can suppress wear of the contact portion 32. As a result, the lifespan of the lower roller 21 and the track links 18 of the crawler belt 17 can be extended, and reliability can be improved.

[0055] Furthermore, the supply control device 31 controls the lubricant supply device 23 to automatically supply lubricant when it receives a rotation stop signal for the lower roller 21 from the rotation speed sensor 22. This eliminates the need for cumbersome operations for supplying lubricant, thereby improving workability.

[0056] Meanwhile, the lower roller 21 includes a roller portion 21B that contacts the inner surface 18A of the track link 18 that constitutes the crawler belt 17, and the lubricant supply device 23 is configured to supply lubricant toward an upper position of the roller portion 21B that is opposite the inner surface 18A of the track link 18. Therefore, the lubricant discharged to the upper position of the roller portion 21B can be moved downward by the rotation of the roller portion 21B and gravity, and supplied to the contact portion 32 between the roller portion 21B and the track link 18. This allows the lubricant to reduce frictional resistance and suppress wear at the contact portion 32.

[0057] Furthermore, the lubricant supply device 23 includes a lubricant tank 24 for storing lubricant, a supply line 25 extending from the lubricant tank 24 to the lower roller 21, a pump 26 provided in the supply line 25 for pumping the lubricant, a valve 28 provided in the supply line 25 downstream of the pump 26 and controlled by a supply control device 31, and an outer nozzle 29 and an inner nozzle 30 provided downstream of the valve 28 and connected to the supply line 25 for discharging the lubricant.

[0058] As a result, when the valve 28 is opened by the supply control device 31, the lubricant supply device 23 can discharge the lubricant, which is pressure-fed by the pump 26 from the lubricant tank 24, from the outer nozzle 29 and the inner nozzle 30 through the supply pipe 25. Moreover, since the outer nozzle 29 and the inner nozzle 30 are configured to open downward and discharge the lubricant, the discharge direction of the lubricant does not oppose the direction of gravity, and the lubricant can be supplied from above downward with little resistance, ensuring that it adheres to the lower roller 21.

[0059] 7 and 8 show a second embodiment of the present invention. The second embodiment is characterized in that the lubricant supply device supplies lubricant toward the inner surface of the crawler belt that contacts the lower roller. In the second embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and their description will be omitted.

[0060] In Figure 7, a lubricant supply device 41 according to the second embodiment includes the lubricant tank 24, supply pipeline 25, pump 26, valve 28, and supply control device 31 according to the first embodiment, as well as an outer nozzle 42 and an inner nozzle 43, which will be described later.

[0061] 8, outer nozzles 42 are provided downstream of the valve 28, i.e., connected to the outer pipe 25B of the supply pipe 25. Eight outer nozzles 42 (only three are shown) are provided corresponding to the eight lower rollers 21 (the outer roller portions 21B). The outer nozzles 42 supply lubricant toward the inner surfaces 18A of the track links 18 constituting the crawler belt 17 that come into contact with the lower rollers 21.

[0062] The outer nozzle 42 is located in front of the roller portion 21B of the lower roller 21, and extends downward from the outer pipe 25B toward the crawler belt 17. The upstream side of the outer nozzle 42 is connected to the outer pipe 25B, the middle portion is bent inward at the lower end of the outer side surface 13D of the track side frame 13, and the downstream side extends downward at the side surface 21B1 of the roller portion 21B. The downstream tip of the outer nozzle 42 opens as a discharge port 42A near the track link 18. This discharge port 42A is cut obliquely so that the outer side is longer.

[0063] The outer nozzle 42 discharges the lubricant supplied from the outer pipe 25B from the discharge port 42A, thereby supplying the lubricant toward the inner surface 18A of the track link 18 of the crawler belt 17 that comes into contact with the lower roller 21. The lubricant supplied to the inner surface 18A flows over the inner surface 18A and is supplied to the contact portion 32 between the circumferential surface 21B2 of the roller portion 21B and the inner surface 18A of the track link 18. This makes it possible to suppress wear at the contact portion 32 by the lubricant.

[0064] On the other hand, the inner nozzle 43 serving as a nozzle is provided downstream of the valve 28, i.e., connected to the inner pipe 25C of the supply pipe 25. Eight inner nozzles 43 (only one shown) are provided corresponding to the eight lower rollers 21 (the roller portions 21B located on the inner side). The inner nozzles 43 supply lubricant toward the inner surfaces 18A of the track links 18 constituting the crawler belt 17 that come into contact with the lower rollers 21.

[0065] The inner nozzle 43 is located in front of the roller portion 21B of the lower roller 21, and extends downward from the inner pipe 25C toward the crawler belt 17. The upstream side of the inner nozzle 43 is connected to the inner pipe 25C, the middle part is bent outward at the lower end of the inner surface 13C of the track side frame 13, and the downstream side extends downward at the side surface 21B1 of the roller portion 21B. The downstream tip of the inner nozzle 43 opens as a discharge port 43A near the track link 18. This discharge port 43A is cut obliquely so that its inner side is longer.

[0066] The inner nozzle 43 discharges the lubricant supplied from the inner pipe 25C from the discharge port 43A, thereby supplying the lubricant toward the inner surface 18A of the track link 18 of the crawler belt 17 that comes into contact with the lower roller 21. The lubricant supplied to the inner surface 18A flows over the inner surface 18A and is supplied to the contact portion 32 between the circumferential surface 21B2 of the roller portion 21B and the inner surface 18A of the track link 18. This makes it possible to suppress wear at the contact portion 32 by the lubricant.

[0067] Thus, the second embodiment configured as described above can also achieve the same effects and advantages as the first embodiment. In particular, in the second embodiment, the lubricant supplying device 41 is configured to supply lubricant toward the inner surfaces 18A of the track links 18 of the crawler belt 17 that come into contact with the lower roller 21. This allows the lubricant supplying device 41 to supply lubricant toward the contact portions 32 via the inner surfaces 18A of the track links 18 using the outer nozzles 42 and the inner nozzles 43. As a result, when the lower roller 21 comes into contact with the crawler belt 17 again, the lubricant can suppress wear of the contact portions 32.

[0068] Furthermore, when the track links 18 of the crawler belt 17 rotate as the lower running body 11 travels, the greater the unevenness of the ground beneath the crawler belt 17 at that time, the fewer the number of lower rollers 21 that come into contact with the track links 18. In this case, the lower rollers 21 that have contact portions 32 with the track links 18 rotate in accordance with the rotation of the track links 18. Due to this rotation of the lower rollers 21, the wear behavior that occurs at the contact portions 32 between the lower rollers 21 and the track links 18 transitions from sliding wear, which causes a large amount of wear, to rolling wear, which causes a relatively small amount of wear, thereby extending the component life of the lower rollers 21 and the track links 18.

[0069] In the embodiment, the undercarriage 11 of the hydraulic excavator 1 has been described as an example of the undercarriage of the construction machine. However, the present invention is not limited to this, and can be widely applied to the undercarriage of other construction machines equipped with tracks, such as a bulldozer. [Explanation of symbols]

[0070] 1. Hydraulic excavator (construction machinery) 11 Undercarriage 12 Truck center frame 13 Truck side frame 15 drive wheels 16 Idler 17 Tracks 18 Track Link 18A Inner surface 21 Lower roller 21B Roller part 22 Rotational speed sensor 23,41 Lubricant supply device 24 Lubricant tank 25 Supply pipeline 26 Pump 28 valves 29,42 Outer nozzle (nozzle) 30,43 Inner nozzle (nozzle) 31 Supply control device 32 Contact area

Claims

1. A truck center frame; a pair of track side frames arranged on both sides of the track center frame; a drive wheel provided at a first end in the longitudinal direction of the track side frame; an idler wheel provided at a second end in the longitudinal direction of the track side frame; a crawler belt wound between the drive wheel and the idler wheel; a lower roller provided below the track side frame and guiding the crawler belt between the drive wheel and the idler wheel; In a lower running body of a construction machine comprising: a rotation speed sensor for detecting the rotation speed of the lower roller; a lubricant supply device that supplies lubricant toward a contact portion between the crawler belt and the lower roller; a supply control device that controls the supply of lubricant from the lubricant supply device toward the contact portion when the rotation speed sensor detects that the rotation of the lower roller has stopped during travel; A lower running body of a construction machine, comprising:

2. The undercarriage of the construction machine according to claim 1, The supply control device controls the lubricant supply device to automatically supply lubricant upon receiving a signal from the rotation speed sensor indicating that the lower roller has stopped rotating.

3. The undercarriage of the construction machine according to claim 1, the lower roller includes a roller portion that contacts an inner surface of the crawler belt, The undercarriage of a construction machine, wherein the lubricant supply device supplies lubricant toward an upper position of the roller portion opposite the inner surface of the crawler belt.

4. The undercarriage of the construction machine according to claim 1, The lubricant supply device supplies lubricant toward an inner surface of the crawler belt that contacts the lower roller.

5. The undercarriage of the construction machine according to claim 1, The lubricant supply device is a lubricant tank for storing a lubricant; a supply line extending from the lubricant tank to the lower roller; a pump provided in the supply line for pumping the lubricant; a valve provided in the supply line downstream of the pump and controlled by the supply control device; a nozzle located downstream of the valve and connected to the supply line, the nozzle discharging the lubricant; A lower running body of a construction machine, comprising:

Images