Work machine connection structure

Abstract

Prevents insufficient lubrication of rotary bearings and thrust bearings. [Solution] In a swing-type hydraulic excavator, a connecting structure that attaches a work implement to a main unit so that it can swing laterally includes a main unit pivotal connection portion of the main unit, a bracket unit pivotal connection portion of the work implement, and a connecting pin that is inserted into an insertion hole that is formed vertically through the main unit with the bracket unit pivotal connection portion placed on the main unit pivotal connection portion. The connecting pin also includes a cylindrical first rotary bearing that is disposed between the outer peripheral surface of the connecting pin and the inner peripheral surface of the insertion hole, a disk-shaped thrust bearing that is disposed between the upper surface surrounding the insertion hole in the main unit pivotal connection portion and the lower surface surrounding the insertion hole in the bracket unit pivotal connection portion, and a lubricant supply structure that supplies grease to the thrust bearing. The lubricant supply structure includes a first grease nipple provided on the upper part of the connecting pin and a supply passage that extends downward from the first grease nipple through the interior of the connecting member pin to supply grease to the thrust bearing.

Description

[Technical Field]

[0001] The present invention relates to a work machine configured by attaching a work implement to a main unit so that the work implement can swing laterally, and more particularly to a connecting structure that attaches the work implement to the main unit so that the work implement can swing laterally. [Background technology]

[0002] One example of such a work machine is a swing-type hydraulic excavator configured with a working device for performing excavation work attached to the front of the vehicle body so that it can swing laterally (freely swing laterally or freely swing laterally) (see, for example, Patent Document 1 and Patent Document 2). A known hydraulic excavator is configured with an upper rotating body (main body) equipped with a cabin that is mounted on a traveling device so that it can swing laterally, and a working device mounted on the front of the upper rotating body. Among hydraulic excavators configured in this way, there is also one configured so that the working device is mounted on the front of the upper rotating body so that it can swing laterally (freely swing laterally), and this is known as a swing-type hydraulic excavator. A swing-type hydraulic excavator is provided with a connecting structure for connecting the working device to the front of the upper rotating body so that it can swing laterally.

[0003] This connection structure is configured such that a main body-side pivotal connection is provided at the front of the upper rotating body and a work-side pivotal connection is provided at the base end of the working device, and the main body-side pivotal connection and the work-side pivotal connection are connected by a connecting member (connecting pin). In this case, it is necessary to connect the upper rotating body and the working device so that they can swing freely in the lateral direction, after the working device is supported by the upper rotating body. Therefore, with the work-side pivotal connection placed on the main body-side pivotal connection and the working device supported by the upper rotating body, a connecting pin is inserted into an insertion hole formed through the support in the vertical direction, and the work-side pivotal connection is connected to the main body-side pivotal connection via the connecting pin so that it can swing freely in the lateral direction.

[0004] In this type of connection structure, to allow smooth lateral swing of the working-side pivotal connection part relative to the main-body pivotal connection part, a rotary bearing member is provided between the outer periphery of the connecting pin and the insertion hole, and a disk-shaped thrust bearing member is provided between the two at the part where the working-side pivotal connection part is placed on the main-body pivotal connection part, surrounding the connecting pin. This allows smooth lateral swing of the working-side pivotal connection part about the connecting pin relative to the main-body pivotal connection part, i.e., smooth lateral swing of the working device relative to the upper rotating body, when the working-side pivotal connection part is placed on the main-body pivotal connection part and the working device is supported by the upper rotating body.

[0005] A lubricant such as grease is supplied to the rotary bearing members and thrust bearing members to enable them to function as bearings. Grease is a semi-solid gel-like material containing lubricating oil, and is injected into the bearing parts in advance to ensure smooth operation as a bearing. Generally, the injected grease gradually decreases as the bearing parts operate, so the bearing parts need to be periodically replenished with grease.

[0006] In a swing-type hydraulic excavator, a connection structure that connects an upper rotating body and a work implement so that they can swing laterally freely also has a grease inlet provided outside a portion of the pivotal connection on the main body side where an insertion hole into which a connecting pin is inserted is provided, a grease supply path is provided from the grease inlet to the inner surface of the insertion hole, and grease is supplied from the grease inlet through the grease supply path. Specifically, a grease nipple is attached to the grease inlet, and grease is supplied under pressure from the grease nipple using a grease injection tool called a grease gun. By supplying grease under pressure from the grease nipple using the grease gun, grease can be forcibly supplied into the insertion hole through the grease supply path, and grease can be supplied to a rotary bearing member provided on the outer periphery of the connecting pin inserted into the insertion hole. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-303223 [Patent Document 2] Japanese Patent Application Publication No. 2017-186828 Summary of the Invention [Problem to be solved by the invention]

[0008] In the connection structure that connects the upper rotating body and the work device so that they can swing laterally, as described above, a rotary bearing member is provided between the outer periphery of the connecting pin and the insertion hole, and a disk-shaped thrust bearing member is provided between the two, surrounding the connecting pin, when the work-side pivotal connection part is placed on the main-body-side pivotal connection part, with the upper part of the rotary bearing member connected to the inner periphery of the thrust bearing member. Therefore, when grease is supplied under pressure from the grease nipple using a grease gun, the grease is supplied to the rotary bearing member through the grease supply path, and further grease can be supplied to the thrust bearing member from the upper part of the rotary bearing member. As a result, the rotary bearing member and the thrust bearing member are supplied with grease and function as bearings.

[0009] In this way, grease is first supplied to the rotary bearing member, and then the grease that flows out from the top of the rotary bearing member under pressure from the grease gun is supplied to the thrust bearing member. Therefore, care must be taken to ensure that the thrust bearing member is supplied with sufficient grease. Furthermore, the injected grease gradually decreases as the connecting part rotates, and because the thrust bearing member is located above the rotary bearing member, there is a problem that the thrust bearing member is more susceptible to grease shortage (insufficient lubrication) than the rotary bearing member. Because the thrust bearing member bears the load from the working device, the problem of grease shortage (insufficient lubrication) in the thrust bearing member is particularly likely to occur when the working device is large and the load from the working device is heavy, such as in a large swing-type hydraulic excavator.

[0010] The present invention has been made in consideration of such problems, and aims to provide a connecting structure that attaches a working device to a main body device so that the working device can swing laterally, and that does not cause insufficient lubrication of the rotary bearing member and thrust bearing member. [Means for solving the problem]

[0011] In order to achieve this objective, the connecting structure of a work machine (for example, the "swing type hydraulic excavator 1" in the embodiments) of the present invention is a connecting structure for connecting a work machine comprising a main body device and a work device attached to the main body device so that the work device can swing laterally, and is configured to include a main body side pivot connection portion (for example, the "main body side pivot connection portion 70" in the embodiments) provided on the main body device, a work side pivot connection portion (for example, the "bracket side pivot connection portion 60a" in the embodiments) provided on the work device, and a connecting member (for example, the "upper connecting pin 80" in the embodiments) that is inserted into an insertion hole (for example, the "first main body side insertion hole 75a and the first bracket side insertion hole 75b" in the embodiments) formed through the work device when the work side pivot connection portion is placed on the main body side pivot connection portion, and connects the work side pivot connection portion to the main body side pivot connection portion so that the work side pivot connection can swing laterally. The present invention also includes a cylindrical rotary bearing member (e.g., "first rotary bearing 90" in the embodiment) disposed between the outer peripheral surface of the connecting member and the inner peripheral surface of the insertion hole, a disk-shaped thrust bearing member (e.g., "thrust bearing 85" in the embodiment) disposed between the upper surface of the main body side pivot connection portion surrounding the insertion hole in the main body side pivot connection portion and the lower surface of the work side pivot connection portion surrounding the insertion hole in the work side pivot connection portion when the work side pivot connection portion is placed on the main body side pivot connection portion, and a first lubricant supply structure (e.g., In the embodiment, it is "a structure consisting of a grease supply port, a storage space 100 and a first communicating hole 102 for supplying grease (lubricant) to the thrust bearing 85"), and the first lubricant supply structure is provided with a first lubricant supply port (for example, the "grease supply port" in the embodiment) provided at the top of the connecting member, and a first lubricant supply path (for example, the "storage space 100 and the first communicating hole 102" in the embodiment) that extends downward from the first lubricant supply port through the inside of the connecting member to supply lubricant to the thrust bearing member.

[0012] In the present invention having the above configuration, preferably, the connecting member (e.g., "upper connecting pin 80" in the embodiment) has a hollow cylindrical shape having a hollow cylindrical space penetrating in the vertical direction, a lid member (e.g., "lid member 81" in the embodiment) covering the hollow cylindrical space is provided on the upper part of the connecting member, a partition member (e.g., "partition member 82" in the embodiment) dividing the hollow cylindrical space in the vertical direction is provided in the middle part of the hollow cylindrical upper space, and a storage space (e.g., "storage space" in the embodiment) is formed in the hollow cylindrical space of the connecting member surrounded by the lid member and the partition member. The cover member is provided with the first lubricant supply port (e.g., the "grease supply port" in the embodiments) that is connected to the storage space, and the connecting member is formed with a first communication hole (e.g., the "first communication hole 102" in the embodiments) that leads from the storage space to the thrust bearing member, and the storage space and the first communication hole form the first lubricant supply path, so that the lubricant supplied from the first lubricant supply port is stored in the storage space, and the grease stored in the storage space is supplied to the thrust bearing member through the first communication hole.

[0013] In the present invention having the above configuration, preferably, the lubricant is grease, and the first lubricant supply port is configured with a grease nipple (for example, "first grease nipple 101" in the embodiment), and the grease injected from the grease nipple and stored in the storage space is supplied to the thrust bearing member through the first communicating hole.

[0014] In the present invention having the above configuration, it is preferable that a second lubricant supply structure be provided that supplies lubricant to the rotary bearing member (for example, a "structure that can supply grease from the second grease nipple 105 through the second communicating hole 106 to the first rotary bearing 90" in the embodiments), and the second lubricant supply structure be provided with a second lubricant supply port (for example, the "second grease nipple 105" in the embodiments) provided on the outer surface of the main body side pivot connection portion, and a second lubricant supply path (for example, the "second communicating hole 106" in the embodiments) that supplies lubricant from the second lubricant supply port through the inside of the main body side pivot connection portion to the rotary bearing member.

[0015] In the present invention having the above configuration, preferably, the end of the first lubricant supply passage that leads to the thrust bearing member is also connected to the upper end of the rotary bearing member, and the lubricant supplied from the first lubricant supply port through the first lubricant supply passage is also supplied to the rotary bearing member. [Effects of the Invention]

[0016] The coupling structure for a working machine according to the present invention includes the rotation bearing member, the thrust bearing member, and the first lubricant supply structure, and the first lubricant supply structure includes a first lubricant supply port provided in an upper part of the coupling member and a first lubricant supply passage extending downward from the first lubricant supply port through the interior of the coupling member to supply lubricant to the thrust bearing member. Therefore, lubricant can be supplied directly from the first lubricant supply port to the thrust bearing member via the first lubricant supply passage, thereby preventing insufficient lubrication of the thrust bearing. In particular, because the first lubricant supply port is provided in an upper part of the coupling member and the first lubricant supply passage extends downward from the first lubricant supply port through the interior of the coupling member, when the lubricant injected into the thrust bearing member gradually decreases as the coupling member swings, the lubricant remaining in the first lubricant supply passage flows into the thrust bearing member by the action of gravity, thereby more reliably preventing insufficient lubrication of the thrust bearing member.

[0017] In the coupling structure for a working machine according to the present invention configured as described above, it is preferable that the coupling member has a hollow cylindrical shape having a hollow cylindrical space penetrating in the vertical direction, the storage space is formed in the hollow cylindrical space surrounded by the cover member and the partition member, and lubricant supplied from the first lubricant supply port provided in the cover member is stored in the storage space and supplied to the thrust bearing member through the first communication hole. With this configuration, since the lubricant is stored in the storage space, when the lubricant injected into the thrust bearing is gradually reduced as the coupling part swings, the lubricant stored in the storage space flows into the thrust bearing member due to the action of gravity, thereby more reliably preventing insufficient lubrication of the thrust bearing.

[0018] The connecting structure for a working machine according to the present invention having the above configuration preferably includes a second lubricant supply structure for supplying lubricant to the rotary bearing member. This allows lubricant to be supplied to the rotary bearing member from a second lubricant supply port provided on the outer surface of the main body-side pivotal connection part through the second lubricant supply path, thereby effectively preventing insufficient lubrication of the rotary bearing member.

[0019] In the connecting structure for a working machine according to the present invention configured as described above, it is preferable that the end of the first lubricant supply passage leading to the thrust bearing member also connects to the upper end of the rotary bearing member, and the lubricant supplied from the first lubricant supply port through the first lubricant supply passage is also supplied to the rotary bearing member. Because the rotary bearing member is provided below the thrust bearing member, lubricant flowing out from the thrust bearing member flows into the rotary bearing member, making it possible to more effectively prevent insufficient lubrication of the rotary bearing member. [Brief explanation of the drawings]

[0020] [Figure 1] 1 is a perspective view of a hydraulic excavator, which is an example of a work machine according to the present invention. [Figure 2] FIG. 2 is a perspective view showing a connecting structure of the working machine. [Figure 3] FIG. 2 is a side view showing the connecting structure of the working machine. [Figure 4] FIG. 2 is a perspective view showing a connecting structure of the working machine. [Figure 5] FIG. 2 is a side cross-sectional view of the connecting structure. [Figure 6] FIG. 2 is a front cross-sectional view of the connecting structure. [Figure 7] FIG. 2 is a plan cross-sectional view of the connection structure. DETAILED DESCRIPTION OF THE INVENTION

[0021] An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a swing-type hydraulic excavator 1, an example of a work machine according to the present invention. The hydraulic excavator 1 comprises a traveling device 10 for traveling, a main unit (upper rotating body) 20 mounted on the upper part of the traveling device 10 so as to be rotatable laterally, and a working device 30 mounted on the front part of the main unit 20 so as to be swingable laterally (swingable laterally). The swing-type hydraulic excavator 1 travels on the ground to perform work, and the main unit 20 is mounted on the traveling device 10, which is in contact with the ground. For this reason, in the following embodiment, the direction in which gravity acts will be described as the up-down direction, and the horizontal direction perpendicular to the up-down direction will be described as the lateral direction (front-rear, left-right direction). However, the ground on which the swing-type hydraulic excavator 1 travels and works is not limited to being horizontal and may be inclined. In such cases, the up-down and lateral directions will naturally be inclined relative to the vertical and horizontal directions determined by the action of gravity. Alternatively, for ease of operation, the working device 30 may be provided on the main unit 20 so that it swings in a direction tilted to a certain degree rather than perpendicular to the vertical direction. The terms "vertical direction" and "lateral direction" in this disclosure take such tilts into consideration, and include directions tilted relative to the direction of gravity and the horizontal direction within the scope of the effects of the invention described below.

[0022] The traveling device 10 is configured by providing crawler mechanisms 15, each having a driven wheel 11, a driving wheel 12, and a track 13 wound around the driven wheel, on the left and right sides of a lower traveling body 16. The left and right crawler mechanisms 15 are provided with left and right traveling motors (not shown) that rotate the left and right driving wheels 12. The traveling device 10 can travel in any direction and at any speed by controlling the rotation direction and rotation speed of the left and right traveling motors. A blade 18 is provided at the front of the lower traveling body 16 so as to be able to swing up and down. The blade 18 is configured to swing up and down by extending and retracting blade cylinders 19, 19 that are provided between the lower traveling body 16 and the crawler mechanisms 15.

[0023] A main body frame 21 is attached to the upper center of the lower traveling body 16 so as to be able to rotate freely via a rotation drive mechanism (not shown). A cabin 25 and a power unit 27 equipped with an engine, a hydraulic supply unit, etc. are attached to the main body frame 21, and these components constitute the main body 20.

[0024] A working device 30 is attached to the front of main body frame 21 via connecting structure 50. Working device 30 includes a boom bracket 60 attached to the front of main body frame 21 by connecting structure 50 so as to be freely swingable laterally (freely swingable laterally), a boom 31 attached to boom bracket 60 so as to be freely swingable up and down, an arm 32 attached to the tip of boom 31 so as to be freely swingable up and down, and a bucket 33 attached to the tip of arm 32 so as to be freely swingable up and down.

[0025] The boom bracket 60 can be swung laterally (made to swing) by extending and retracting a swing cylinder 35 (see FIG. 4) mounted between the main frame 21 and the boom bracket 60. The boom 31 can be swung in a vertical plane by extending and retracting a boom cylinder 36 mounted between the boom bracket 60 and the boom 31. The arm 32 can be swung in a vertical plane by extending and retracting an arm cylinder 37 mounted between the boom 31 and the arm 32. The bucket 33 can be swung in a vertical plane relative to the arm 32 via a link mechanism 34 by extending and retracting a bucket cylinder 38 mounted between the arm 32 and the bucket 33.

[0026] Although not shown, an operator seat on which an operator sits and operating devices that can be operated by the operator sitting in the operator seat are provided inside a cabin 25 provided on the main body frame 21 of the main body 20. The operating devices include, for example, travel operating levers for operating the traveling device 10, and work operating levers for operating the swing of the main body 20 and the work device 30.

[0027] The power unit 27 includes a hydraulic drive unit that supplies hydraulic oil to drive the left and right travel motors and blade cylinder of the travel unit 10, the swing motor of the main unit 20, and the swing cylinder, boom cylinder 36, arm cylinder 37, and bucket cylinder 38 (hydraulic actuators) of the work unit 30. This hydraulic drive unit is composed of a diesel engine, a hydraulic pump driven by the engine, and a control valve that controls the direction and flow rate of hydraulic oil supplied to the hydraulic actuators. When an operator sits in the operator's seat and operates the travel control levers and work control levers, the control valve is operated and controlled according to the operation state, controlling the direction and flow rate of hydraulic oil supplied to the hydraulic actuators and driving the hydraulic actuators.

[0028] Next, we will explain the connecting structure 50 that connects the boom bracket 60 of the working device 30 to the main body frame 21 of the main body device 20 so that it can swing freely within a lateral plane. Fig. 2 shows an enlarged perspective view of the connecting structure 50 as seen diagonally from above, Fig. 3 shows an enlarged view of the connecting structure 50 as seen from the side, and Fig. 4 shows a perspective view of the connecting structure 50 as seen diagonally from above on the opposite side to the left and right of Fig. 2, and we will explain with reference to these figures.

[0029] The connecting structure 50 connects a main body pivotal connection 70, which is formed at the front of the main body frame 21, to a bracket pivotal connection 60a (working side pivotal connection) which is formed at the base of the boom bracket 60, using an upper connecting pin 80 (see FIGS. 5 to 7) and a lower connecting pin (not shown). The main body pivotal connection 70 has a front end that is bifurcated, upper and lower, and includes an upper main body pivotal connection 71 and a lower main body pivotal connection 76. A cylindrical upper main body holding portion 72 is connected to the upper main body pivotal connection 71, and a cylindrical lower main body holding portion 77 is connected to the lower main body pivotal connection 76. The bracket pivotal connection 60a has a base end that is bifurcated, upper and lower, and includes an upper bracket pivotal connection 60a and a lower bracket pivotal connection 66. The upper bracket pivotal connection 60a is further bifurcated, upper and lower, and includes a first upper bracket arm 62 and a first lower bracket arm 63. The lower bracket side pivot connection portion 66 is also bifurcated into a second upper bracket arm 67 and a second lower bracket arm 68 .

[0030] As shown in FIG. 3, the boom bracket 60 is attached to the main body frame 21 such that the upper main body-side holding portion 72 is sandwiched from above and below by the first upper bracket arm 62 and the first lower bracket arm 63, and the lower main body-side holding portion 77 is sandwiched from above and below by the second upper bracket arm 67 and the second lower bracket arm 68. With the upper main body-side holding portion 72 sandwiched from above and below by the first upper bracket arm 62 and the first lower bracket arm 63, a first insertion hole (consisting of a main body-side first insertion hole 75a and a bracket-side first insertion hole 75b, as shown in FIGS. 5 and 6) is formed that penetrates these portions vertically. An upper connecting pin 80 is inserted into this first insertion hole, connecting the bracket-side pivotal connection portion 60a to the main body-side pivotal connection portion 70 so that the bracket-side pivotal connection portion 60a can swing laterally. This connecting structure is referred to as the upper connecting structure 50a. Furthermore, with the lower main body-side retaining portion 77 sandwiched between the second upper bracket arm 67 and the second lower bracket arm 68 from above and below, a second insertion hole is formed that vertically penetrates these and is coaxial with the first communicating hole, and a lower connecting pin is inserted into this second insertion hole, connecting the bracket-side pivot connection portion 60a to the main body-side pivot connection portion 70 so that it can swing laterally. This connecting structure is referred to as the lower connecting structure 50b. In this way, the bracket-side pivot connection portion 60a is connected to the main body-side pivot connection portion 70 so that it can swing laterally by the upper and lower connecting pins inserted into the first and second insertion holes that are formed to extend coaxially vertically.

[0031] The upper connecting structure 50a is shown enlarged in Figures 5 to 7, and the upper connecting structure 50a will be described with reference to these figures. Figure 5 is an enlarged cross-sectional view of the upper connecting structure 50a in the same side view as Figure 3, but cut away. Figure 6 is a cross-sectional view of the upper connecting structure 50a taken along arrows VI-VI in Figure 5. Figure 7 is a cross-sectional view of the upper connecting structure 50a taken along arrows VII-VII in Figure 6.

[0032] As shown in these figures, the upper main body side holding part 72 is sandwiched between the first upper bracket arm 62 and the first lower bracket arm 63, and first insertion holes are formed that penetrate them vertically. The first insertion holes are formed coaxially and with the same diameter, lined up one above the other, and include an upper main body side holding part insertion hole 72a that penetrates the upper main body side holding part 72 vertically, a first upper bracket arm insertion hole 62a that penetrates the first upper bracket arm 62 vertically, and a first lower bracket arm insertion hole 63a that penetrates the first lower bracket arm 63 vertically. An upper connecting pin 80 is inserted into the first insertion holes formed in this way.

[0033] The upper end of the upper connecting pin 80 is connected to and attached to the first upper bracket arm 62. A thin, cylindrical first upper bushing 93 is disposed in the space surrounded by the first upper bracket arm insertion hole 62a on the outer circumferential surface of the upper connecting pin 80. The first upper bushing 93 is press-fitted and fixed in the first upper bracket arm insertion hole 62a. A thin, cylindrical first lower bushing 95 is disposed in the space surrounded by the first lower bracket arm insertion hole 63a on the outer circumferential surface of the upper connecting pin 80. The first lower bushing 95 is press-fitted and fixed in the first lower bracket arm insertion hole 63a. A thin, cylindrical first rotary bearing 90 is disposed in the space surrounded by the upper main body side holding portion insertion hole 72a on the outer circumferential surface of the upper connecting pin 80. The first rotary bearing 90 functions as a bearing against lateral swing of the working device 30 relative to the main body side pivotal connection portion 70. Although not shown, a plurality of grease grooves are formed on the cylindrical outer peripheral surface and inner peripheral surface of the first rotary bearing 90.

[0034] Although not shown, the lower connecting structure 50b has a similar configuration to the upper connecting structure 50a. However, because thrust forces are received by the upper connecting structure 50a and not by the lower connecting structure 50b, the lower connecting structure 50b does not include a thrust bearing, as described below. In other words, the lower connecting structure 50b is not included in the scope of the present invention. For this reason, the lower connecting structure 50b will be briefly described without specifying specific component numbers. The lower body side retaining portion 77 is sandwiched between the second upper bracket arm 67 and the second lower bracket arm 68, and second insertion holes are formed vertically through these arms. The second insertion holes are formed coaxially and vertically, with the same diameter, and aligned vertically. The lower body side retaining portion insertion hole vertically penetrates the lower body side retaining portion 77, the second upper bracket arm insertion hole vertically penetrates the second upper bracket arm 67, and the second lower bracket arm insertion hole vertically penetrates the second lower bracket arm 68. The lower connecting pins are inserted into the second insertion holes formed in this manner.

[0035] A thin, cylindrical second upper bushing is disposed in the space surrounded by the second upper bracket arm insertion hole on the outer peripheral surface of the lower connecting pin. The second upper bushing is press-fitted and fixed in the second upper bracket arm insertion hole. A thin, cylindrical second lower bushing is disposed in the space surrounded by the second lower bracket arm insertion hole on the outer peripheral surface of the lower connecting pin. The second lower bushing is press-fitted and fixed in the second lower bracket arm insertion hole. A thin, cylindrical second rotary bearing is disposed in the space surrounded by the lower main body side retaining portion insertion hole on the outer peripheral surface of the lower connecting pin. A plurality of grease grooves are also formed on the cylindrical outer peripheral surface and inner peripheral surface of the second rotary bearing.

[0036] In this way, the bracket side pivot connection part 60a is connected to the main body side pivot connection part 70 (main body frame 21) by the upper and lower connecting pins so that it can swing laterally, but the working device 30 must be supported by the main body frame 21, and the vertical load from the working device 30 is received and supported by the main body side pivot connection part 70. Specifically, the upper surface of the upper main body side holding part 72 and the lower surface of the first upper bracket arm 62 are abutted against each other, and the vertical load from the working device 30 is received and supported by the main body side pivot connection part 70 at this abutting part.

[0037] In this way, to allow the boom bracket 60 to smoothly swing laterally relative to the main frame 21 while the main body pivot connection 70 receives and supports the vertical load from the working device 30, a thin, disk-shaped thrust bearing 85 is provided between the upper surface of the upper main body support 72, which is an embodiment of the "main body pivot connection upper surface" of the present disclosure, and the lower surface of the first upper bracket arm 62, which is an embodiment of the "working device pivot connection upper surface" of the present disclosure. This thrust bearing 85 receives the vertical thrust force acting on the main body pivot connection 70 from the working device 30 and also functions as a bearing against lateral swing of the working device 30 relative to the main body pivot connection 70. The thrust bearing 85 is disk-shaped as shown in FIG. 7, and has a spiral grease groove 85a formed on its surface. The thrust bearing 85 has a retaining protrusion 86 protruding outward from its outer periphery, and a retaining hole 86a is formed in the retaining protrusion 86. 2 and 3, a retaining pin 71a is provided on the upper surface of the upper main body side pivotal connection part 71, and the retaining pin 71a fits into the retaining hole 86a to attach the thrust bearing 85. This restricts the rotation of the thrust bearing 85 relative to the upper main body side pivotal connection part 71.

[0038] 4, a swing arm 64 is integrally connected to the bracket side pivot connection portion 60a and protrudes laterally, and the tip of the swing cylinder 35 is pivotally connected to the tip of the swing arm 64. The base end of the swing cylinder 35 is pivotally connected to the main body frame 21, and by extending and contracting the swing cylinder 35, the boom bracket 60 can be driven to swing laterally relative to the main body frame 21.

[0039] As described above, the bracket-side pivotal connection portion 60a is connected to the main body-side pivotal connection portion 70 (main body frame 21) so as to be swingable laterally by the first rotary bearing 90 of the upper connecting structure 50a and the second rotary bearing of the lower connecting structure 50b. Furthermore, the main body-side pivotal connection portion 70 (main body frame 21) supports the working device 30 while allowing lateral swing by the thrust bearing 85. Grease is supplied to the first rotary bearing 90, second rotary bearing, and thrust bearing 85 so that they can function as bearings. This grease supply structure will be described below.

[0040] In the upper connecting structure 50a, as shown in FIGS. 5 and 6, the upper connecting pin 80 is formed in a hollow cylindrical shape, its upper end covered by a lid member 81, and a partition member 82 attached to the middle of the cylindrical space. As a result, a storage space 100 is formed in the hollow cylindrical space inside the upper connecting pin 80, surrounded by the lid member 81 and the partition member 82. A first grease nipple 101 is attached to the lid member 81 as a grease supply port, and grease can be supplied into the storage space 100 from the first grease nipple 101 using a grease gun or the like. The upper connecting pin 80 is formed with a plurality of first communication holes 102 connecting the storage space 100 to the outer peripheral surface. The ends of the first communication holes 102 open at positions on the outer peripheral surface of the upper connecting pin 80 facing the inner peripheral portion of the thrust bearing 85. The above configuration, namely, the first grease nipple 101 attached as a grease supply port, the storage space 100, and the first communication hole 102 constitute a first lubricant supply structure that supplies grease (lubricant) to the thrust bearing 85. The first grease nipple 101 serves as the first lubricant supply port, and the storage space 100 and the first communication hole 102 constitute a first lubricant supply path.

[0041] The thrust bearing 85, which is provided between the upper surface of the upper main body side holding portion 72 and the lower surface of the first upper bracket arm 62, has its inner periphery sandwiched between the lower surface of the first upper bushing 93 and the upper surface of the first rotary bearing 90, and faces the outer periphery of the upper connecting pin 80. Therefore, grease stored in the storage space 100 is supplied to the thrust bearing 85 through the first communicating hole 102. As described above, the rotation of the thrust bearing 85 relative to the upper main body side pivot connection portion 71 is restricted, and the upper surface of the thrust bearing 85 and the lower surface of the first upper bracket arm 62 rotate relatively. Because grease is required in areas where there is relative rotation, the thrust bearing 85 is mainly supplied to the upper surface of the thrust bearing 85 through the first communicating hole 102.

[0042] The upper end of the first rotary bearing 90 is located close to the inner periphery of the thrust bearing 85 and is connected to the end of the first communicating hole 102. Therefore, some of the grease supplied to the thrust bearing 85 through the first communicating hole 102 is also supplied to the first rotary bearing 90. Furthermore, a second communicating hole 106 that leads to the upper body side holding part insertion hole 72a is formed in the middle of the upper body side holding part 72 in the vertical direction, and a second grease nipple 105 is attached to the outer periphery of the second communicating hole 106. This forms a second lubricant supply structure that can supply grease from the second grease nipple 105 through the second communicating hole 106 to the first rotary bearing 90 using a grease gun or the like.

[0043] Although not shown, in the lower connecting structure 50b, a third communication hole that reaches the lower body side holder insertion hole is formed in the vertical middle position of the lower body side holder 77, and a second grease nipple is attached to the outer periphery of this third communication hole. This makes it possible to supply grease from the second grease nipple through the third communication hole to the second rotary bearing using a grease gun or the like.

[0044] The hydraulic excavator 1 configured as described above undergoes periodic maintenance to ensure its proper operation. One example of this maintenance is the periodic supply of grease to the thrust bearing 85 and the first rotary bearing 90 in the upper connecting structure 50a. This maintenance is performed by supplying grease from the first grease nipple 101 into the storage space 100 using a grease gun or the like. The grease supplied into the storage space 100 is supplied to the thrust bearing 85 through the first communication hole 102 under supply pressure from the grease gun and is also supplied to the first rotary bearing 90. Although the supply pressure from the grease gun is applied only during supply, because the storage space 100 is located above the thrust bearing 85 and the first rotary bearing 90, even if the grease supplied to the thrust bearing 85 and the first rotary bearing 90 decreases due to work by the hydraulic excavator 1, grease is replenished from the storage space 100 by the action of gravity. Therefore, the problem of insufficient grease in the thrust bearing 85 and the first rotary bearing 90 can be reliably prevented.

[0045] Furthermore, regular maintenance of the lower connecting structure 50b is performed by supplying grease from the second grease nipple through the third communication hole to the second rotary bearing using a grease gun or the like. This is a conventional maintenance method.

[0046] Although the embodiments of the present invention have been described above, the scope of the present invention is not limited to the above-described embodiments. For example, in the above-described embodiments, the present invention is applied to a crawler-traveling hydraulic excavator, but the present invention can also be applied to wheel-traveling hydraulic excavators and work machines other than hydraulic excavators, such as hydraulic cranes. [Explanation of symbols]

[0047] 1 Swing type hydraulic excavator (work machine) 10 Traveling device 20 Main unit 21 Main frame 30 Working equipment 50 Connection structure 60 Boom bracket 61 Upper bracket side pivot connection 62 First upper bracket arm 63 First lower bracket arm 66 Lower bracket side pivot connection portion 67 Second upper bracket arm 68 Second lower bracket arm 64 Swing arm 70 Main body side pivot joint 71 Upper main body side pivot joint 72 Upper body side holding part 76 Lower body side pivoting part 77 Lower body side holding portion 71a Holding pin 80 upper connecting pin 81 cover member 82 Partition member 85 Thrust bearing 85a Grease groove 86 Retaining projection 86a Retaining hole 90 First rotary bearing 93 First upper bush 95 First lower bush 100 storage space 101 first grease nipple 102 First communication hole 105 Second grease nipple 106 2nd communication hole

Claims

1. In a work machine comprising a main body and a working device attached to the main body so as to be swingable laterally, a connection structure for connecting the working device to the main body so as to be swingable laterally, comprising: the main body side pivotal connection part is provided on the main body device, the work side pivotal connection part is provided on the work device, and a connecting member is inserted into an insertion hole formed through in the vertical direction with the work side pivotal connection part placed on the main body side pivotal connection part, and connects the work side pivotal connection part to the main body side pivotal connection part so that the work side pivotal connection part can swing laterally, a cylindrical rotary bearing member disposed between an outer peripheral surface of the connecting member and an inner peripheral surface of the insertion hole; a disk-shaped thrust bearing member disposed between an upper surface of the main body side pivot connection portion surrounding the insertion hole in the main body side pivot connection portion and a lower surface of the work side pivot connection portion surrounding the insertion hole in the work side pivot connection portion when the work side pivot connection portion is placed on the main body side pivot connection portion; and a first lubricant supply structure that supplies lubricant to the thrust bearing member, The first lubricant supply structure is a first lubricant supply port provided on an upper portion of the connecting member; and a first lubricant supply path extending downward from the first lubricant supply port through the interior of the connecting member to supply lubricant to the thrust bearing member.

2. the connecting member has a hollow cylindrical shape having a hollow cylindrical space penetrating in the up-down direction, a cover member covering the hollow cylindrical space is provided on the upper part of the connecting member, and a partition member dividing the hollow cylindrical space in the up-down direction is provided in the middle part of the upper space of the hollow cylinder, a storage space is formed in the hollow cylindrical space of the connecting member, surrounded by the cover member and the partition member; the first lubricant supply port connected to the storage space is provided in the lid member, a first communication hole extending from the storage space to the thrust bearing member is formed in the connecting member, the storage space and the first communication hole form the first lubricant supply path, 2. A working machine coupling structure as described in claim 1, wherein the lubricant supplied from the first lubricant supply port is stored in the storage space, and the grease stored in the storage space is supplied to the thrust bearing member through the first communicating hole.

3. 3. A working machine coupling structure as described in claim 2, wherein the lubricant is grease, the first lubricant supply port is configured with a grease nipple, and grease injected from the grease nipple and stored in the storage space is supplied to the thrust bearing member through the first communicating hole.

4. a second lubricant supply structure for supplying lubricant to the rotary bearing member; The second lubricant supply structure is 4. A working machine connection structure according to claim 1, further comprising: a second lubricant supply port provided on the outer surface of the main body side pivotal connection portion; and a second lubricant supply path that supplies lubricant from the second lubricant supply port through the inside of the main body side pivotal connection portion to the rotary bearing member.

5. 4. A working machine coupling structure according to claim 1, wherein an end of the first lubricant supply passage that leads to the thrust bearing member is also connected to an upper end of the rotary bearing member, and the lubricant supplied from the first lubricant supply port through the first lubricant supply passage is also supplied to the rotary bearing member.

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