JP2012144141A - Traveling body of tracklaying vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a travelling body of a tracklaying vehicle capable of reducing wear due to sliding contact between a slider and a track shoe and thereby extending the lives of the slider and the track shoe.SOLUTION: There is provided a grease supplier 24 for automatically supplying grease between the contact surface 23A of a slider 23 and the slider contact surface 19B of a track shoe 19. The grease supplier 24 constructed of a grease reservoir tank 25 for reserving the grease, a grease pump 26 for delivering the grease reserved in the reservoir tank 25, a grease supply hole 29 provided to the slider 23 and a grease supply pipe passage 28 connecting the grease supply hole 29 with the grease pump 26. Of the grease supply pipe passage 28, a portion exposed from a side frame 14 is covered by a protection cover 30.

Description

  The present invention relates to a traveling body of a tracked vehicle having a crawler track such as a hydraulic excavator or a hydraulic crane.

  In general, a tracked vehicle such as a hydraulic excavator or a hydraulic crane has a self-propelled lower traveling body, an upper revolving body that is turnably mounted on the lower traveling body, and work provided on the upper revolving body. It is roughly constituted by the device.

  Here, for example, a lower traveling body of a large tracked vehicle includes a track frame having a center frame and side frames extending in the front and rear directions on both left and right sides of the center frame, and each side of the track frame. A drive wheel provided on one side in the length direction of the frame, an idle wheel provided on the other side in the length direction of each side frame, a crawler belt wound around the drive wheel and the idle wheel, It is generally configured by a slider that is provided on the upper surface side of each side frame and guides the crawler belt between the driving wheel and the idler wheel (see, for example, Patent Documents 1 and 2).

  Such a lower traveling body, for example, by rotationally driving the drive wheels by a traveling hydraulic motor, sequentially engages the outer peripheral side of the drive wheels with the protrusions arranged on the inner surface of the crawler belt, The vehicle can travel by rotating around the idler wheel. At this time, the slider is guided to support the crawler track from below while sliding on the inner surface of the crawler track.

JP 2008-149899 A Japanese Patent Laid-Open No. 9-277964

  According to the prior art, wear of the slider and the crawler belt that are in sliding contact with each other (friction contact) is likely to proceed, and the life (replacement time) of the slider and the crawler belt may be shortened.

  The present invention has been made in view of the above-described problems of the prior art, and can reduce the wear caused by sliding contact between the slider and the crawler belt, and can extend the life of the slider and the crawler belt. The purpose is to provide.

  In order to solve the above-described problems, the present invention provides a track frame having a center frame and side frames extending in the front and rear directions on the left and right sides of the center frame, and the length direction of each side frame of the track frame. A drive wheel provided on one side, idle wheels provided on the other side in the length direction of each side frame, crawler belts wound around the drive wheels and idle wheels, and each side The present invention is applied to a traveling body of a tracked vehicle that is provided on a frame and includes a slider that guides the crawler belt between the driving wheel and the idle wheel.

  A feature of the configuration adopted by the invention of claim 1 is that a lubrication device is provided that automatically supplies lubricating oil to a sliding contact portion between the slider and the crawler belt.

  According to a second aspect of the present invention, the greasing device has a greasing hole provided in the slider corresponding to the sliding contact portion, and a greasing pipe that guides the lubricating oil to the greasing hole. The side frame is provided with a protective cover that covers a portion of the grease supply pipe that is exposed from the side frame.

  According to a third aspect of the present invention, there is provided a hydraulic pump, a variable displacement type hydraulic motor connected to the hydraulic pump via a main line and rotationally driving the drive wheel, and a capacity control circuit for variably controlling the capacity of the hydraulic motor. A direction control valve provided in the middle of the main pipeline, a parking brake that applies a braking force to the drive wheel when the hydraulic motor is stopped, a capacity control of the capacity control circuit, and / or a brake control of the parking brake The grease supply device includes an oil storage tank that stores the lubricating oil, and a grease pump that discharges the lubricating oil stored in the oil storage tank. Is that the lubricating oil is discharged using the pilot pressure in the pilot line as power.

  According to the first aspect of the present invention, since the lubrication device for automatically supplying the lubricating oil to the sliding contact portion between the slider and the crawler belt is provided, the sliding contact portion between the slider and the crawler belt is lubricated by the greasing device. can do. Thereby, the frictional resistance and wear between the slider and the crawler belt can be reduced, and the life (replacement time) of the slider and the crawler belt can be extended. As a result, the durability and reliability of the running body of the tracked vehicle can be improved.

  According to the second aspect of the present invention, the protective cover for covering the greasing pipeline is provided on the side frame, so that the protective cover can prevent sediment from being directly deposited on the greasing pipeline. The durability and reliability of the device can be improved.

  According to the invention of claim 3, the grease pump constituting the grease supply device can control the pilot pressure of the pilot line for performing the capacity control of the capacity control circuit for controlling the capacity of the hydraulic motor and / or the brake control of the parking brake. Since the power is used, the greasing pump can be driven in accordance with the traveling of the traveling body of the tracked vehicle, and the sliding contact portion between the slider and the crawler belt can be suitably lubricated. Thereby, further improvement in durability and reliability can be achieved.

It is a front view which shows the hydraulic excavator provided with the lower traveling body by embodiment of this invention. It is a front view which expands and shows the lower traveling body in FIG. It is a top view which shows the right half part of a lower traveling body in the state which omitted the crawler belt. It is an enlarged front view of the (IV) part in FIG. 2 which shows a crawler belt, a slider, a greasing line, a protective cover, etc. It is sectional drawing seen from the arrow VV direction in FIG. 4 which shows a crawler belt, a slider, a greasing line, a protective cover, etc. It is a perspective view which shows a protective cover alone. It is a circuit block diagram which shows a hydraulic pump, a hydraulic motor, a capacity | capacitance control circuit, a parking brake, a pilot pipe line, a greasing apparatus, etc. It is explanatory drawing which shows the time change of the position of a travel lever, the position of a speed change switch, a pilot pressure, a parking brake, and grease supply.

  Hereinafter, as a traveling body of a tracked vehicle according to an embodiment of the present invention, a lower traveling body of a hydraulic excavator will be described as an example and described in detail with reference to the accompanying drawings.

  In the figure, reference numeral 1 denotes a large hydraulic excavator as a tracked vehicle. The hydraulic excavator 1 is a lower traveling body 11 to be described later, an upper revolving body 3 mounted on the lower traveling body 11 via a revolving wheel 2 so as to be able to swivel, and can be moved up and down to the front side of the upper revolving body 3. And a work device 4 that performs earth excavation work and the like.

  Next, 11 shows a track type (crawler type) lower traveling body as a traveling body. The track-type lower traveling body 11 is for traveling stably on uneven ground, muddy ground, and the like. The lower traveling body 11 includes a track frame 12, a traveling hydraulic motor 15, a driving wheel 16, an idler wheel 17, a crawler belt 18, a lower roller 21, a slider 23, a greasing device 24, and the like, which will be described later.

  Reference numeral 12 denotes a track frame of the lower traveling body 11. As shown in FIGS. 2 and 3, the track frame 12 is provided with a center frame 13 located at the center in the left and right directions, and provided on both the left and right sides of the center frame 13 in the front and rear directions. It is comprised by the below-mentioned side frame 14 extended.

  Here, the center frame 13 is formed as a substantially H-shaped structure having four legs 13A extending in the left and right directions (only the right half is shown in FIG. 3). A turning wheel 2 constituting a turning device is attached to the center of the center frame 13, and the upper turning body 3 is mounted via the turning wheel 2. A side frame 14 described later is attached to the tip of each leg portion 13A of the center frame 13.

  Reference numeral 14 denotes a left and right side frame (only the right side is shown) constituting the track frame 12 together with the center frame 13. As shown in FIG. 3, the side frame 14 is disposed so as to extend in the front and rear directions, and is attached to the tip of each leg portion 13 </ b> A of the center frame 13.

  Here, the side frame 14 is formed, for example, as a rectangular tube-shaped can-making structure extending in the front and rear directions by welding strip-shaped steel plates. That is, the side frame 14 includes a vertical inner surface plate 14A located on the inner side in the left and right directions on the center frame 13 side, an outer surface plate 14B facing the inner surface plate 14A in the left and right directions, and an inner surface plate. The upper surface plate 14C is formed by connecting the upper portions of 14A and the outer surface plate 14B, and the inner surface plate 14A and the horizontal lower surface plate 14D fixed to the lower end portions of the outer surface plate 14B.

  Further, drive wheels 16 and idle wheels 17 described later are provided on one side and the other side of the side frame 14 in the length direction. Further, a lower roller 21 described later is attached to the lower surface plate 14D of the side frame 14, and a slider 23 described later is attached to the upper surface plate 14C via a pedestal 22. Further, as shown in FIG. 4 and the like, a pipe hole 14C1 for arranging a greasing pipe 28 to be described later is formed through the portion corresponding to the pedestal 22 in the upper surface plate 14C.

  Reference numeral 15 denotes a traveling hydraulic motor as a hydraulic motor that rotationally drives a drive wheel 16 described later. The traveling hydraulic motor 15 is composed of a variable displacement hydraulic motor such as a swash plate, and is attached to one side of each side frame 14 in the length direction (for example, the left side in FIG. 2). The traveling hydraulic motor 15 is rotationally driven by pressure oil discharged from a main pump 31 (see FIG. 7), which will be described later, and drives the crawler belt 18, which will be described later, through the drive wheels 16.

  Reference numeral 16 denotes a drive wheel called a drive tumbler provided on one side in the length direction of each side frame 14. The drive wheel 16 is attached to the side frame 14 via a traveling hydraulic motor 15 and drives the crawler belt 18 to be described later using the traveling hydraulic motor 15 as power. Here, the drive wheel 16 is formed in an annular shape, and a spline hole (none of which is shown) that is spline engaged with the output shaft of the traveling hydraulic motor 15 is provided on the inner diameter side thereof.

  On the other hand, on the outer diameter side of the drive wheel 16, a large number of meshing parts 16 </ b> A are arranged in the circumferential direction at regular intervals so as to protrude in the axial direction. Each of these meshing portions 16A meshes with an engagement projection 19A of each track shoe 19 constituting a crawler belt 18, which will be described later, and a projection interval is set corresponding to the interval dimension connecting each track shoe 19. ing.

  Reference numeral 17 denotes an idler wheel called an idler provided on the other side in the length direction of each side frame 14 (for example, the right side in FIG. 2). The idler wheel 17 adjusts the tension of the crawler belt 18 by a crawler belt tension adjusting mechanism (not shown), and is biased toward the other side in the length direction of the side frame 14.

  Reference numeral 18 denotes a crawler belt (crawler) provided around the drive wheel 16 and the idle wheel 17. As shown in FIGS. 2 and 4, the crawler belt 18 is configured as an endless track by connecting a large number of track shoes 19 using connecting pins 20.

  Here, as shown in FIGS. 4 and 5 and the like, the track shoe 19 has two engagement protrusions 19A at a predetermined interval in the width direction on the inner circumferential surface of the crawler belt 18 connected in an annular shape. The engaging protrusions 19 </ b> A are engaged with the respective engaging portions 16 </ b> A of the driving wheel 16 to be engaged therewith. Thereby, the drive wheel 16 can reliably transmit the rotational force to the crawler belt 18 without causing slippage.

  Further, both side positions in the width direction of the track shoes 19 constituting the crawler belt 18 (outside positions of the engaging protrusions 19A) are slider contact surfaces 19B. The slider contact surface 19B is in contact with a contact surface 23A of the slider 23 described later.

  Reference numeral 21 denotes a plurality of lower rollers provided on the lower surface plate 14D of the side frame 14, and the lower rollers 21 are arranged at predetermined intervals in the front and rear directions as shown in FIG. Each lower roller 21 is positioned between the drive wheel 16 and the idler wheel 17 and rolls on the inner surface of the crawler belt 18 while guiding the crawler belt 18 from above to the ground. To do.

  Reference numeral 22 denotes a plurality of pedestals provided on the upper surface plate 14C of the side frame 14, and each of the pedestals 22 is, for example, three locations near the idler wheel 17, near the drive wheel 16, and between the leg portions 13A of the center frame 13. Is provided. As shown in FIGS. 4 and 5, a bracket 22A for attaching a lower cover portion 30A of a protective cover 30 (to be described later) is provided on the lower end side of a base 22 provided in the middle portion in the longitudinal direction of the side frame 14. Is provided.

  Reference numeral 23 denotes a plurality of sliders provided on the upper surface plate 14C of the side frame 14 via respective pedestals 22, and each of the sliders 23 is spaced apart in the width direction on, for example, three pedestals 22 as shown in FIG. In total, two of them are provided. Each slider 23 is fixed on the pedestal 22 in a state of being separated in the left and right directions (the width direction of the crawler belt 18). Further, the upper surface of each slider 23 is a contact surface 23A that is slidably contacted (slidably contacted) with the slider contact surface 19B of the track shoe 19. Thereby, each slider 23 can support the crawler belt 18 from the lower side between the driving wheel 16 and the idler wheel 17 and guide it in the circumferential direction.

  Each slider 23 is formed with a later-described greasing hole 29 penetrating upward and downward, and a later-described greasing pipe 28 is connected to the upstream end of the greasing hole 29. The greasing hole 29 and the greasing pipe line 28 constitute a greasing device 24 described later. Through the greasing pipe line 28 and the greasing hole 29, grease is supplied to the contact surface 23A of the slider 23 and the track shoe 19. It can be supplied to the slider contact surface 19B.

  Next, the greasing device 24 that supplies grease between the contact surface 23A of the slider 23 and the slider contact surface 19B of the track shoe 19 will be described.

  That is, 24 is a greasing device that supplies grease as lubricating oil to the sliding portion between the slider 23 and the crawler belt 18. The greasing device 24 automatically supplies grease between the contact surface 23A of the slider 23 and the slider contact surface 19B of the track shoe 19, and will be described later, as shown in FIGS. The grease storage tank 25, the grease pump 26, the grease supply hydraulic motor 27, the grease supply conduit 28, and the grease supply hole 29 are roughly configured.

  Reference numeral 25 denotes a grease storage tank as an oil storage tank for storing grease. The grease storage tank 25 stores therein grease that lubricates a sliding portion between the slider 23 and the crawler belt 18. The grease storage tank 25 is provided in the track frame 12, for example.

  Reference numeral 26 denotes a grease pump as a greasing pump that discharges grease stored in the grease storage tank 25. The grease pump 26 is provided adjacent to the grease storage tank 25 in the track frame 12, for example. The grease pump 26 is driven to rotate by a later-described grease supply hydraulic motor 27, thereby discharging grease in the grease storage tank 25 into a later-described greasing pipeline 28.

  Reference numeral 27 denotes a grease supply hydraulic motor that rotationally drives the grease pump 26. The grease supply hydraulic motor 27 is provided at a position adjacent to the grease pump 26 in a state where, for example, the rotation shaft thereof is connected to the rotation shaft of the grease pump 26. The grease supply hydraulic motor 27 is connected to a pilot line 43 that performs capacity control of the travel hydraulic motor 15 and brake control of the parking brake 42 described later. As a result, the grease supply hydraulic motor 27 is rotationally driven with the pilot pressure in the pilot conduit 43 as power, and the grease pump 26 is rotationally driven by the rotation.

  Reference numeral 28 denotes a greasing line that connects the grease pump 26 and a greasing hole 29 described later. The grease supply conduit 28 is disposed in the side frame 14, and its upstream end is connected to the discharge port of the grease pump 26. Further, as shown in FIGS. 4 and 5 and the like, the downstream end side of the greasing pipeline 28 protrudes upward from the upper surface plate 14C of the side frame 14 through the piping hole 14C1 of the side frame 14, and from the upper surface plate 14C. The protruding portion is disposed upward and downward along the side surface of the pedestal 22 provided on the upper surface plate 14 </ b> C of the side frame 14.

  The downstream end of the greasing pipe 28 is connected to the upstream end of the greasing hole 29, and the grease discharged from the grease pump 26 is guided to the greasing hole 29. In the circuit configuration diagram of FIG. 7, one greasing pipe 28 is connected to one greasing hole 29, but in reality, the greasing pipe 28 is greasing. Corresponding to the number of holes 29, it is branched in the middle. As shown in FIGS. 4 and 5, each upstream end of the branched greasing pipeline 28 is connected to each greasing hole 29.

  Reference numeral 29 denotes a greasing hole provided in the slider 23 corresponding to the sliding contact portion between the crawler belt 18 and the slider 23. For example, as shown in FIG. 3, the greasing holes 29 are totaled by two sliders 23 supported by a base 22 at the middle portion in the longitudinal direction of each side frame 14, that is, both the left and right side frames 14. Two each of the four sliders 23 are provided apart from each other in the length direction of the slider 23. Here, the greasing hole 29 is formed as a through-hole penetrating upward and downward of the slider 23, and its downstream end opens to the contact surface 23 </ b> A of the slider 23, and its upstream end is the downstream end of the greasing pipe 28. It is connected to the. As a result, the grease supplied to the greasing hole 29 through the greasing line 28 flows out from the greasing hole 29 between the contact surface 23A of the slider 23 and the slider contact surface 19B of the track shoe 19, and these sliders. 23 and the crawler belt 18 (each track shoe 19) can be lubricated.

  Next, a protective cover that protects the greasing line 28 of the greasing device 24 will be described.

  That is, 30 is a protective cover for protecting the greasing pipeline 28, and the protective cover 30 is a portion of the greasing pipeline 28 exposed from the side frame 14, that is, the side as shown in FIGS. It protrudes upward from the piping hole 14C1 of the frame 14 and covers a portion disposed upward and downward along the side surface of the pedestal 22. For this purpose, the protective cover 30 is provided at the four corners of the base 22 between the upper surface of the upper surface plate 14C of the side frame 14 and the lower surface of the slider 23 so as to cover the four corners from the outside.

  Here, as shown in FIG. 6 and the like, the protective cover 30 is provided so as to be connected to the lower cover portion 30A having an L-shaped cross section and the upper end edge of the lower cover portion 30A, and upward from the upper end edge. An inclined portion 30B that inclines in a direction away from the pedestal 22 as it goes, an upper cover portion 30C that is connected to the upper end edge of the inclined portion 30B and has an L-shaped cross section, and an upper end edge of the upper cover portion 30C The bracket portion 30D that is provided along the lower surface of the slider 23 and the cover portion 30E that is provided on the upper cover portion 30C and covers the space between the upper cover portion 30C and the pedestal 22 from the upper side.

  A lower bolt insertion hole 30 </ b> F for bolting the lower cover portion 30 </ b> A to a bracket 22 </ b> A provided on the base 22 is provided on the lower end side of the lower cover portion 30 </ b> A. The bracket portion 30D is provided with an upper bolt insertion hole 30G for bolting the bracket portion 30D to the lower surface of the slider 23. The protective cover 30 fixes the lower cover portion 30A to the bracket 22A of the pedestal 22 using the lower bolt 30H, and fixes the bracket portion 30D to the lower surface of the slider 23 using the upper bolt 30J. The greasing pipelines 28 are respectively attached to the four corners 22.

  Next, a hydraulic circuit for driving the traveling hydraulic motor 15 and supplying grease by the greasing device 24 will be described with reference to FIG.

  In the figure, 31 is a main pump as a hydraulic pump mounted on the upper swing body 3, and the main pump 31 is rotated and driven by a prime mover (not shown) such as an engine and an electric motor together with a pilot pump 44 described later. Thus, the hydraulic oil stored in the hydraulic oil tank 32 is discharged, and various hydraulic actuators including the traveling hydraulic motor 15 are driven.

  The traveling hydraulic motor 15 is connected to the main pump 31 and the hydraulic oil tank 32 via main pipelines 33A and 33B and is driven to rotate by the supply of pressure oil from the main pump 31. Here, the traveling hydraulic motor 15 is constituted by a variable displacement hydraulic motor having a displacement variable portion 15A such as a swash plate or a slant shaft, and the motor capacity is variable according to the tilt angle of the displacement variable portion 15A, for example. Are controlled by

  The traveling hydraulic motor 15 is rotated at a low speed with a high torque when the motor capacity is large due to the pressure oil from the main pump 31. In this case, for example, the hydraulic excavator 1 is given a sufficient climbing force. The traveling speed of the excavator 1 is set to a relatively slow speed. On the other hand, when the motor capacity is small, the traveling hydraulic motor 15 is rotated at high speed with low torque by the pressure oil from the main pump 31, and the traveling speed of the excavator 1 is increased.

  Reference numeral 34 denotes a capacity control circuit that variably controls the capacity of the traveling hydraulic motor 15. The capacity control circuit 34 is roughly composed of a tilt control cylinder 35 (described later) and a capacity control valve 36.

  Reference numeral 35 denotes a tilt control cylinder that tilts and drives the capacity variable portion 15 </ b> A of the traveling hydraulic motor 15. The tilt control cylinder 35 feeds and discharges the pressure oil from the main pipe line 33A or 33B via a capacity control valve 36, which will be described later, so that the capacity variable portion 15A of the traveling hydraulic motor 15 is changed to an arrow in FIG. It is tilted in the directions indicated by A and B.

  Reference numeral 36 denotes a capacity control valve that controls supply and discharge of pressure oil to the tilt control cylinder 35. The capacity control valve 36 is controlled to be switched between a large capacity position (A) and a small capacity position (B) in accordance with a pilot pressure (command pressure) P in a pilot line 43 described later. While the displacement control valve 36 is in the large displacement position (A), the displacement variable portion 15A of the traveling hydraulic motor 15 is tilted and driven in the direction indicated by the arrow A by the tilt control cylinder 35. The motor capacity of the hydraulic motor 15 is set to a large capacity (low speed). On the other hand, when the capacity control valve 36 is switched to the small capacity position (B), the capacity variable portion 15A is tilted in the direction indicated by the arrow B by the tilt control cylinder 35, whereby the travel hydraulic motor 15 is driven. Set the capacity to a small capacity (high speed).

  Reference numeral 37 denotes a traveling direction control valve provided in the middle of the main pipelines 33A and 33B. The direction control valve 37 is switched from the neutral position (A) to the switching positions (B) and (C) by, for example, a travel lever 37A operated by the operator of the excavator 1, and the switching positions (B) and (C). Thus, the rotation direction of the traveling hydraulic motor 15 is switched to the directions indicated by arrows F and R in FIG. Further, when the directional control valve 37 is returned to the neutral position (A), the supply of hydraulic oil from the main pump 31 toward the traveling hydraulic motor 15 is cut off, and the traveling hydraulic motor 15 is stopped. It is.

  A brake circuit 38 is located between the traveling hydraulic motor 15 and the direction control valve 37 and is provided in the middle of the main pipelines 33A and 33B. The brake circuit 38 includes a counter balance valve 39 and a relief valve 40 which will be described later. , 41 and the like. When the traveling hydraulic motor 15 rotates inertially when the direction control valve 37 returns to the neutral position (A), the brake circuit 38 opens one of the relief valves 40 and 41 to open the main line 33A, In 33B, the pressure oil on the high pressure side is relieved to the low pressure side, and a braking force is applied to the traveling hydraulic motor 15.

  A counter balance valve 39 is provided between the traveling hydraulic motor 15 and the directional control valve 37 and is provided in the middle of the main pipelines 33A and 33B. The counter balance valve 39 is provided with a return spring 39A on both the left and right sides. , 39B are provided, and when the directional control valve 37 is switched, it is switched from the neutral position (A) to the switching positions (B), (C) against the return springs 39A, 39B so as to be interlocked therewith. It has become.

  That is, when the directional control valve 37 is switched from the neutral position (A) to the switching position (B), (C), the counter balance valve 39 guides the pressure oil from the main pump 31 to the pilot lines 39C, 39D. As a result, the position is switched from the neutral position (A) to the left and right switching positions (B) and (C) against the return springs 39A and 39B. The counter balance valve 39 allows the pressure oil from the main pump 31 to be supplied to the traveling hydraulic motor 15 when switching to the switching positions (B) and (C), The return oil from the pump 31 is discharged to the hydraulic oil tank 32 to the side.

  When the directional control valve 37 is returned to the neutral position (A), the counter balance valve 39 is also returned to the neutral position (I) by the return springs 39A and 39B. Then, the counter balance valve 39 blocks the return oil discharged from the traveling hydraulic motor 15 during inertia rotation from flowing out to the hydraulic oil tank 32 side at the neutral position (A), so that the traveling hydraulic pressure is reduced. A brake pressure is generated in the main pipeline 33A or 33B with the motor 15, and a braking force is applied to the traveling hydraulic motor 15 by the brake pressure.

  Further, when the vehicle descends on a slope or the like, the traveling hydraulic motor 15 may be rotated by inertia due to the inertial force in the downhill direction acting on the vehicle, and the traveling hydraulic motor 15 may perform a pumping action. Also in this case, the counter balance valve 39 returns to the neutral position (A), and the brake pressure is generated in the main line 33A or 33B with the traveling hydraulic motor 15, thereby preventing the vehicle from running away. To do.

  Reference numerals 40 and 41 denote a pair of relief valves which are located between the main hydraulic passages 33A and 33B and are located between the traveling hydraulic motor 15 and the counter balance valve 39. The relief valves 40 and 41 are connected to the traveling hydraulic motor 15 respectively. When the brake pressure generated in the main line 33A or 33B becomes an excess pressure higher than the relief set pressure during the inertia rotation, the valve is opened and the excess pressure is relieved to the other side of the main line 33B or 33A. During this time, the relief valves 40 and 41 absorb the inertia energy of the traveling hydraulic motor 15 to gradually stop the traveling hydraulic motor 15 and prevent an overload from acting on the traveling hydraulic motor 15. To do.

  Here, the relief valves 40 and 41 are configured as a relief valve with an accumulator, and have a stepwise relief characteristic with respect to the pressure of the main pipeline 33A or 33B. That is, when the pressure in the main pipe line 33A or 33B increases, pressure oil is supplied into the oil storage chamber 40A or 41A of the relief valve 40 or 41 via the throttles 40B and 41B. While pressure oil is supplied into 41A, the valve opening pressure of the relief valve 40 or 41 is made low so that sudden braking due to sudden increase in brake pressure can be prevented.

  Reference numeral 42 denotes a negative parking brake that applies a braking force to the drive wheels 16 (travel hydraulic motor 15) when the travel hydraulic motor 15 is stopped. The parking brake 42 is connected to a pilot pipeline 43 (43A), which will be described later. When the pilot pressure in the pilot pipeline 43 (43A) exceeds a predetermined brake release pressure, the parking brake 42 is released and the drive wheel 16 (running) The hydraulic motor 15) is allowed to rotate.

  Reference numeral 43 is a pilot line that performs capacity control of the capacity control circuit 34 and brake control of the parking brake 42. The pilot line 43 is connected to the pilot pump 44, the hydraulic oil tank 32, and the pilot line 43 via an electromagnetic switching valve 45 described later. Are selectively connected. Further, the other end side of the pilot pipe 43 is branched halfway into the brake side branch pipe 43A and the capacity control side branch pipe 43B, the brake side branch pipe 43A is the parking brake 42, and the capacity control side branch pipe 43B is the capacity. Each is connected to the pilot chamber of the control valve 36.

  Reference numeral 44 denotes a pilot pump mounted on the upper swing body 3. The pilot pump 44 is rotated together with a main pump 31 by a prime mover such as an engine or an electric motor, so that the hydraulic oil stored in the hydraulic oil tank 32 is stored. Is discharged. The pilot pump 44 is connected to the capacity control valve 36, the parking brake 42, and the grease supply hydraulic motor 27 of the greasing device 24 through a pilot line 43 (43 </ b> A, 43 </ b> B).

  45 is an electromagnetic switching valve provided in the middle of the pilot pipe line 43. The electromagnetic switching valve 45 is configured as, for example, a proportional electromagnetic switching valve, and the pilot pump 44 and the hydraulic oil tank 32 are selectively provided on the inflow side thereof. The outlet side is connected to the capacity control valve 36, the parking brake 42, and the grease supply hydraulic motor 27 via a pilot line 43 (43A, 43B). The electromagnetic switching valve 45 generates a predetermined pilot pressure (command pressure) P between the discharge pressure of the pilot pump 44 and the tank pressure (0) based on a control signal from the control unit 46, for example. is there.

  More specifically, the electromagnetic switching valve 45 generates a predetermined pilot pressure P corresponding to, for example, the position of the traveling lever 37A (direction control valve 37) that is switched by the operator and the position of the speed switching switch 47. (Adjust to a predetermined pilot pressure P). For this purpose, for example, on the input side of the control unit 46, a traveling lever sensor 48 that detects whether the traveling lever 37A is in the stop position or the traveling position, and a hydraulic excavator when the operator performs a switching operation. A speed changeover switch 47 for switching the traveling speed of 1 to either low speed or high speed is connected. On the other hand, the output side of the control unit 46 is connected to the electromagnetic switching valve 45.

  For example, when the traveling lever 37A is in the stop position, that is, when the direction control valve 37 is in the neutral position (A), the electromagnetic switching valve 45 sets the pilot pressure P, the release pressure of the parking brake 42, and the capacity control valve 36. The pressure is lower than both the switching pressure and the drive start pressure of the grease supply hydraulic motor 27, for example, 0 (tank pressure). As a result, the parking brake 42 is operated, the grease supply hydraulic motor 27 is not driven, and the capacity control valve 36 is in the large capacity position (A).

  On the other hand, when the travel lever 37A is operated from the neutral position to the travel position (for example, the forward position or the reverse position), that is, when the direction control valve 37 is switched to the switching position (B) or (C), the electromagnetic The switching valve 45 sets the pilot pressure P to a pressure that exceeds at least both the release pressure of the parking brake 42 and the drive pressure of the grease supply hydraulic motor 27. At this time, if the speed changeover switch 47 is in the low speed position, the electromagnetic changeover valve 45 exceeds the pilot pressure P by both the release pressure of the parking brake 42 and the drive start pressure of the grease supply hydraulic motor 27. The switching pressure of the control valve 36 is set to a lower pressure (for example, a low pressure).

  As a result, the parking brake 42 is released, the grease supply hydraulic motor 27 is driven, and the capacity control valve 36 is in the large capacity position (A). At this time, the grease pump 26 is rotationally driven by the grease supply hydraulic motor 27, and the grease stored in the grease storage tank 25 passes through the greasing line 28 and the greasing hole 29 and the contact surface 23 </ b> A of the slider 23 and the track shoe 19. To the slider contact surface 19B. Thereby, the sliding contact part of the slider 23 and the crawler belt 18 (each track shoe 19) is lubricated, and the frictional resistance and wear of the sliding contact part can be reduced.

  When the speed changeover switch 47 is operated to the high speed position, the electromagnetic changeover valve 45 sets the pilot pressure P, the release pressure of the parking brake 42, the drive start pressure of the grease supply hydraulic motor 27, and the capacity control valve 36. The pressure is higher than any of the switching pressures (for example, high pressure). As a result, the parking brake 42 is released, the grease supply hydraulic motor 27 is driven, and the capacity control valve 36 is in the small capacity position (B). Also at this time, since the grease pump 26 is rotationally driven by the grease supply hydraulic motor 27 and grease is supplied to the sliding contact portion between the slider 23 and the crawler belt 18, the frictional resistance and wear of the sliding contact portion are reduced. Can do.

  In the figure, 49 indicated by a one-dot chain line is a center joint for allowing the hydraulic oil to flow between the upper swing body 3 and the lower traveling body 11 regardless of the swing operation of the upper swing body 3. Reference numeral 50 denotes a return pipe (drain pipe) for returning the hydraulic oil to the hydraulic oil tank 32.

  The hydraulic excavator 1 according to the present embodiment has the above-described configuration. Next, the operation when the excavator 1 travels with the lower traveling body 11 will be described.

  First, when the operator operates the travel lever 37A to switch the direction control valve 37 from the neutral position (A) to the switching position (B), the counter balance valve 39 is switched from the neutral position (A) in conjunction with this operation. Switch to position (b). The traveling hydraulic motor 15 is supplied with pressure oil from the main pump 31 via the main line 33A, and the return oil is discharged to the hydraulic oil tank 32 via the main line 33B. As a result, the traveling hydraulic motor 15 is rotationally driven in the direction of arrow F, and the lower traveling body 11 moves forward. When the direction control valve 37 is switched from the neutral position (A) to the switching position (C), the counter balance valve 39 is switched to the switching position (C), and the traveling hydraulic motor 15 is driven to rotate in the direction indicated by the arrow R. Then, the lower traveling body 11 moves backward.

  In this case, if the speed changeover switch 47 operated by the operator is in the low speed position, the pilot pressure P in the pilot line 43 is reduced by the electromagnetic changeover valve 45 (the release pressure of the parking brake 42 and the grease supply hydraulic motor 27). The displacement control valve 36 of the displacement control circuit 34 is held at the large displacement position (A). For this reason, the displacement variable portion 15A of the traveling hydraulic motor 15 is tilted in the direction of arrow A by the tilt control cylinder 35, and the motor capacity is set to a large capacity. As a result, the traveling hydraulic motor 15 is rotated at a low speed with high torque by the motor driving pressure from the main pump 31, and the excavator 1 is driven to travel at a low speed with sufficient torque.

  On the other hand, when the speed changeover switch 47 is operated from the low speed position to the high speed position, the pilot pressure P in the pilot line 43 is increased by the electromagnetic switching valve 45 (the release pressure of the parking brake 42, the drive of the grease supply hydraulic motor 27). The starting pressure is adjusted to a pressure exceeding the switching pressure of the capacity control valve 36), and the capacity control valve 36 is switched to the small capacity position (B). Therefore, the displacement variable portion 15A of the traveling hydraulic motor 15 is tilted in the direction indicated by the arrow B by the tilt control cylinder 35, and the motor capacity is set to a small capacity. As a result, the traveling hydraulic motor 15 is rotated at high speed with low torque by the motor driving pressure from the main pump 31, and the hydraulic excavator 1 can be driven to travel at high speed.

  In any case, when the hydraulic excavator 1 travels, the meshing portion 16A of the drive wheel 16 that is rotationally driven by the travel hydraulic motor 15 meshes with the engagement protrusion 19A of each track shoe 19, so that the drive wheel 16 The crawler belt 18 can be rotated around the idler wheel 17, and the lower traveling body 11 can be driven by the circular movement of the crawler belt 18. Further, when the crawler belt 18 is in a circling motion, the lower rollers 21 and the sliders 23 guide the crawler belt 18 in the circling direction. At this time, the slider contact surface 19B of each track shoe 19 constituting the crawler belt 18 is The slider 23 comes into contact (sliding contact) with the contact surface 23A.

  In this case, according to the present embodiment, since the grease supplying device 24 for automatically supplying the grease to the sliding contact portion between the slider 23 and the crawler belt 18 is provided, the slider 23 and the crawler belt 18 are provided by the grease supplying device 24. The sliding contact portion can be lubricated.

  That is, as shown in FIG. 8, when the operator operates the traveling lever 37A from the neutral position to the forward position or the reverse position, the directional control valve 37 changes from the neutral position (A) to the switching position (B) or (C). When switched, the pilot pressure P in the pilot line 43 is adjusted to a pressure (low pressure or high pressure) higher than the release pressure of the parking brake 42 and the driving start pressure of the grease supply hydraulic motor 27 by the electromagnetic switching valve 45. .

  As a result, the parking brake 42 is released and the grease supply hydraulic motor 27 is driven so that the grease stored in the grease storage tank 25 passes through the greasing line 28 and the greasing hole 29 and contacts the contact surface 23A of the slider 23. And the slider contact surface 19B of the track shoe 19. And the sliding contact site | part of the slider 23 and the crawler belt 18 is lubricated by the grease supplied in this way, and the frictional resistance and abrasion of the said sliding contact site | part can be reduced. As a result, the lifetime (replacement time) of the slider 23 and the crawler belt 18 can be extended, and the durability and reliability of the lower traveling body 11 can be improved.

  Further, according to the present embodiment, the protective cover 30 that covers the greasing pipeline 28 of the greasing device 24 is provided between the upper surface plate 14C of the side frame 14 and the lower surface of the slider 23. The protective cover 30 can prevent the earth and sand from directly depositing on the oil conduit 28, and the durability and reliability of the greasing device 24 can be improved.

  Further, according to the present embodiment, the grease pump 26 constituting the grease supplying device 24 is driven by the grease supply hydraulic motor 27 driven by the pilot pressure P of the pilot pipe 43. Here, the pilot pressure P in the pilot line 43 is for performing the capacity control of the capacity control circuit 34 that controls the capacity of the traveling hydraulic motor 15 and the brake control of the parking brake 42. The grease pump 26 can be driven by the grease supply hydraulic motor 27 in accordance with the traveling (with the traveling of the lower traveling body 11). Thereby, the sliding contact portion between the slider 23 and the crawler belt 18 can be suitably lubricated according to the traveling of the lower traveling body 11, and also from this aspect, the durability and reliability of the lower traveling body 11 can be improved. Can be planned.

  In the embodiment described above, the case where the greasing hole 29 is provided in the slider 23 supported by the pedestal 22 at the intermediate portion in the longitudinal direction of the side frame 14 has been described as an example. However, the present invention is not limited to this, and for example, a configuration may be adopted in which greasing holes are provided in all the sliders supported on the side frames via the pedestals.

  Further, in the above-described embodiment, the pilot pipe line 43 is described by taking as an example a case where both the capacity control of the traveling hydraulic motor 15 and the brake control of the parking brake 42 are performed using the same pilot pipe line 43. did. However, the present invention is not limited to this. For example, the displacement control of the traveling hydraulic motor and the brake control of the parking brake may be performed using different pilot pipelines. In this case, the greasing pump of the greasing device can be driven using, for example, the pilot pressure of the pilot line that performs brake control of the parking brake as power.

  Furthermore, in embodiment mentioned above, the lower traveling body 11 of the hydraulic shovel 1 is illustrated as a traveling body of a tracked vehicle. However, the present invention is not limited to this, and can be widely applied to traveling bodies of other tracked vehicles such as a hydraulic crane and a bulldozer.

1 Hydraulic excavator (tracked vehicle)
11 Lower traveling body (traveling body)
12 Track frame 13 Center frame 14 Side frame 15 Traveling hydraulic motor (hydraulic motor)
16 Drive Wheel 17 Idle Wheel 18 Crawler Track 23 Slider 24 Greasing Device 25 Grease Storage Tank (Oil Storage Tank)
26 Grease pump (Grease pump)
28 Greasing pipeline 29 Greasing hole 30 Protective cover 31 Main pump (hydraulic pump)
33A, 33B Main pipeline 34 Capacity control circuit 37 Directional control valve 42 Parking brake 43 Pilot pipeline

Claims (3)

A track frame having a center frame and side frames extending in the front and rear directions on both the left and right sides of the center frame; and a drive wheel provided on one side in the length direction of each side frame of the track frame; An idler wheel provided on the other side in the length direction of each side frame, a crawler belt wound around the drive wheel and the idler wheel, and the drive wheel and idler wheel provided in each side frame; In a tracked vehicle traveling body comprising a slider for guiding the crawler belt between,
A tracked vehicle traveling body characterized in that a lubrication device for automatically supplying lubricating oil to a sliding contact portion between the slider and the crawler belt is provided.   The greasing device has a greasing hole provided in the slider corresponding to the sliding contact portion, and a greasing conduit for guiding the lubricating oil to the greasing hole, The traveling body of a tracked vehicle according to claim 1, wherein a protective cover is provided to cover a portion exposed from the side frame in the greasing pipeline. A hydraulic pump, a variable displacement hydraulic motor connected to the hydraulic pump via a main line and rotationally driving the drive wheel, a capacity control circuit for variably controlling the capacity of the hydraulic motor, and a middle of the main line A direction control valve provided in the vehicle, a parking brake that applies a braking force to the drive wheel when the hydraulic motor is stopped, and a pilot pipe that performs capacity control of the capacity control circuit and / or brake control of the parking brake. Prepared,
The greasing device includes an oil storage tank that stores the lubricating oil, and a greasing pump that discharges the lubricating oil stored in the oil storage tank, and the greasing pump includes a pilot pressure of the pilot line. The traveling body of the tracked vehicle according to claim 1, wherein the lubricating oil is discharged using the power as a power source.

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