JP2012172718A - Bearing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To promote reduction in size and weight and improve assembling workability by simplifying an attachment tool for attaching a cover to a counter member while reducing the load acting on the attachment tool.SOLUTION: A shaft end housing recess 17B for housing a protruding end portion 16A of the connecting pin 16 is provided on a cover 17 after a connecting pin 16 is provided with both ends thereof being protruded beyond an outside end surface 14B of a bracket 14 in an axial direction. A cover bush 20 for rotatably supporting the protruding end portion 16A of the connecting pin 16 is provided inside the shaft end housing recess 17B of the cover 17. In a state where the protruding end portion 16A of the connecting pin 16 is fitted in the recess 17B of the cover 17 through the cover bush 20, a large load acting on the cover 17 can be supported by the connecting pin 16 through the bush 20 to reduce the load acting on a bolt 19.

Description

  The present invention relates to a bearing device suitable for use in, for example, a pin coupling portion of a working device equipped on a hydraulic excavator.

  In general, a hydraulic excavator as a construction machine is provided with a self-propelled lower traveling body, an upper revolving body that is turnably mounted on the lower traveling body, and a front-rear side of the upper revolving body that can be raised and lowered. It is roughly constituted by a working device. The working device includes a boom, an arm, a bucket, and a hydraulic cylinder that drives the boom. A bearing device is provided between the swing frame of the upper swing body and the boom, between the boom and the arm, and between the arm and the bucket. Are connected to each other in a rotatable manner.

  Here, among the rotating parts of the working device, for example, the bearing device used for the rotating part between the arm and the bucket is a cylindrical shape provided with a pin insertion hole provided on the tip side of the arm and extending in the axial direction. Boss, a boss bush provided in the pin insertion hole of the boss, and a bucket side provided with a pin insertion hole at a position corresponding to the pin insertion hole provided opposite to the boss in the axial direction. A pair of brackets, bracket bushes provided in the pin insertion holes of the brackets, a boss bush and the bracket bushes, and the bosses and the brackets connected to each other so as to be relatively rotatable. A pin and a cover provided on the outer end face in the axial direction of each bracket so as to face the end of the connection pin in order to prevent the connection pin from being pulled out. There. The cover is attached to the outer end surface of the bracket using a plurality of bolts (see, for example, Patent Document 1).

JP 2001-173670 A

  By the way, according to the above-mentioned Patent Document 1, since the cover is attached to the bucket side bracket using bolts, for example, when rocks collide with the cover during excavation work, most of the load caused by the collision May act on the bolt and the load (shear load, etc.) may damage the bolt. For this reason, it is necessary to increase the number of bolts or increase the number of bolts, which is an obstacle to miniaturization and weight reduction, and there is a problem that assembly workability is lowered.

  The present invention has been made in view of the above-described problems of the prior art, and an object of the present invention is to simplify the structure of the fixture by reducing the load acting on the fixture for attaching the cover to the counterpart member. Another object of the present invention is to provide a bearing device that can be reduced in size and weight, and that can improve assembly workability.

  A bearing device according to the present invention is provided with a cylindrical boss formed with a pin insertion hole extending in the axial direction, a boss bush provided in the pin insertion hole of the boss, and facing the boss in the axial direction. A pair of counterpart members each having a pin insertion hole formed at a position corresponding to the pin insertion hole, a counterpart member bush provided in the pin insertion hole of each counterpart member, the boss bush and each counterpart A connecting pin that is inserted into the member bush and connects the boss and each counterpart member so as to be relatively rotatable, and a shaft of each counterpart member so as to face the end of the connection pin to prevent the connection pin from being pulled out. And a cover provided on the outer end face in the direction.

  In order to solve the above-described problem, the feature of the configuration adopted by the invention of claim 1 is that both end portions of the connecting pin are provided so as to protrude in the axial direction from the outer end surface of each counterpart member, and the cover is provided on the cover. Is provided with a shaft end receiving recess for receiving the protruding end of the connecting pin, and a cover bush for rotatably supporting the protruding end of the connecting pin is provided in the shaft end receiving recess of the cover. It is in the configuration.

  The invention according to claim 2 is that the cover is configured to be attached to the outer end surface of the counterpart member using a bolt.

  According to the first aspect of the present invention, both ends of the connecting pin protruding in the axial direction from each bracket are inserted into the shaft end receiving recess provided in the cover via the cover bush. Therefore, even if a rock or the like collides with the cover and a large load is applied, this load can be received by the high-strength connecting pin through the cover bush. Thereby, since most of the load caused by the collision can be received by the connecting pin, the load acting on the fixture such as a bolt for attaching the cover to the counterpart member can be reduced.

  As a result, when a bolt is used as a fixture for attaching the cover to the bracket, the bolt can be made thinner or the number thereof can be reduced, so that the bearing device can be reduced in size and weight. In addition, the assembly workability can be improved. Moreover, by inserting the connecting pin into the shaft end receiving recess (cover bush) of the cover, it is possible to easily align the bolt hole between the bracket and the cover. Can be improved.

  In addition, by providing a cover bush in the shaft end accommodating recess of the cover, the cover can be mounted so as not to rattle against the connecting pin, so the load acting on the bolt can be further reduced. it can.

  According to the invention of claim 2, the cover can be easily attached to and detached from the outer end surface of the counterpart member by tightening or loosening the bolt.

1 is a front view showing a hydraulic excavator provided with a working device to which a bearing device according to an embodiment of the present invention is applied. It is sectional drawing which expanded the bearing apparatus from the arrow II-II direction in FIG. FIG. 3 is an enlarged cross-sectional view of a main part showing an arm boss, a bracket, a connecting pin, a cover, a bolt, and the like located at a right side portion of the bearing device in FIG. It is a disassembled sectional view which shows the state which removed the cover and the bush for cover from the bracket. It is an exploded sectional view showing a state where a cover and a cover bush are disassembled. It is a front view which shows a cover alone. It is a front view which shows the bush for covers alone.

  Hereinafter, a case where the bearing device according to the embodiment of the present invention is applied to a hydraulic excavator will be described as an example, and will be described in detail with reference to FIGS. In the present embodiment, a bearing device provided as a pin coupling portion between an arm and a bucket constituting the working device will be described as a representative example.

  In FIG. 1, reference numeral 1 denotes a hydraulic excavator, and the hydraulic excavator 1 is roughly constituted by a crawler-type lower traveling body 2 that can be self-propelled and an upper revolving body 3 that is pivotably mounted on the lower traveling body 2. A working device 5 described later is provided on the front side of the upper swing body 3.

  The upper swing body 3 is provided on the lower traveling body 2 via a swing frame 4 that forms a support structure. The revolving frame 4 has left and right vertical plates (not shown) extending in the front and rear directions, and a working device 5 is provided at a front side position of each vertical plate so as to be able to move up and down.

  Reference numeral 5 denotes a working device provided on the front side of the upper swing body 3 so as to be able to move up and down. The working device 5 performs excavation work of earth and sand. Here, the working device 5 includes a boom 6 whose base end is pivotally connected to the front side position of each vertical plate of the revolving frame 4 and an arm that is pivotally connected to the distal end side of the boom 6. 7 and a bucket 8 that is pivotally connected to the distal end side of the arm 7 by a pin. The boom 6, the arm 7, and the bucket 8 of the work device 5 are driven by the cylinders 9A, 9B, and 9C.

  Here, the arm 7 of the working device 5 is provided with an arm boss 12 which will be described later, located on the tip side. The bucket 8 is provided with a later-described bracket 14 that constitutes a counterpart member according to the present embodiment. The arm 7 and the bucket 8 are pin-coupled so as to be rotatable by a bearing device 11 described later.

  Reference numeral 11 denotes a bearing device according to the present embodiment (see FIG. 2). The bearing device 11 is provided to extend leftward and rightward between the distal end side of the arm 7 and the proximal end side of the bucket 8. The bearing device 11 supports the bucket 8 on the tip side of the arm 7 so as to be capable of relative rotation (rotation). The bearing device 11 includes an arm boss 12, a boss bush 13, a bracket 14, a bracket bush 15, a connecting pin 16, a cover 17, a bolt 19, a cover bush 20, and the like which will be described later.

  Reference numeral 12 denotes an arm boss as a boss integrally provided on the tip end side of the arm 7 by welding or the like. The arm boss 12 is formed in a substantially cylindrical shape extending in the left and right directions using a high-strength steel material, and an inner peripheral side thereof is a pin insertion hole 12A. Further, as shown in FIGS. 2 and 3, boss-side greasing holes 12B are provided on both the left and right sides of the arm boss 12 so as to penetrate in the radial direction. The boss-side greasing hole 12B supplies lubricating oil to a boss bush 13 described later.

  Reference numeral 13 denotes left and right boss bushes provided in the pin insertion hole 12A of the arm boss 12 so as to be separated from each other in the axial direction. The left and right boss bushes 13 form a slide bearing that externally fits a connecting pin 16 described later. Each boss bush 13 is formed in a cylindrical shape, and is fixedly fitted into the pin insertion hole 12A of the arm boss 12 by means such as press fitting.

  A plurality of oil storage grooves 13 </ b> A for storing lubricating oil are provided on the inner peripheral side of the boss bush 13. On the other hand, on the outer peripheral side of the boss bush 13, an annular groove 13B is provided at a position corresponding to the boss-side greasing hole 12B of the arm boss 12. The annular groove 13B penetrates the boss bush 13 in the radial direction. It can communicate with an oil groove 16B of the connecting pin 16 described later through a hole (not shown).

  Reference numeral 14 denotes left and right brackets as mating members integrally provided on the bucket 8 using fixing means such as welding. The bracket 14 is formed in a flat plate shape using a high-strength steel plate in substantially the same manner as the arm boss 12, and is disposed opposite to the arm boss 12 in the axial direction so as to sandwich the arm boss 12 in the left and right directions. . Each bracket 14 is formed with a pin insertion hole 14A at a position corresponding to the pin insertion hole 12A of the arm boss 12.

  The bracket 14 has an outer end surface 14B opposite to the arm boss 12 in the axial direction. A plurality of, for example, five screw holes 14C (only one) are provided on the outer peripheral side of the outer end surface 14B at a predetermined interval in the circumferential direction. (Shown) is provided.

  Reference numeral 15 denotes a bracket bush as a counterpart member bush provided in the pin insertion hole 14 </ b> A of each bracket 14. Each bracket bush 15 forms a cylindrical slide bearing that externally fits a connecting pin 16 to be slidable in the same manner as the boss bush 13, and means such as press fitting is provided in the pin insertion hole 14A. It is fixedly fitted using.

  A plurality of oil storage grooves 15 </ b> A for storing lubricating oil are provided on the inner peripheral side of the bracket bush 15. Each of the oil storage grooves 15A can communicate with a cover-side greasing hole 17D of the cover 17 via an oil groove 16C of a connecting pin 16 described later.

  Reference numeral 16 denotes a connecting pin that connects the arm boss 12 and each bracket 14 so as to be relatively rotatable. The connecting pin 16 is slidably inserted into the boss bush 13 and each bracket bush 15. Further, the connecting pin 16 is formed as a cylindrical body having a sufficient diameter that can withstand a load (shear load or the like) between the arm boss 12 and each bracket 14.

  Here, as shown in FIG. 4, when the connecting pin 16 is inserted into the arm boss 12 and each bracket 14, both end portions in the axial direction protrude in the axial direction from the outer end face 14 </ b> B of each bracket 14. It is the composition to do. The projecting end portion 16A of the connecting pin 16 has a dimension that allows the cover 17 to be held so as not to be displaced even when a load is applied to the cover 17 described later from the radial direction, that is, sufficient engagement with the cover 17. The projecting dimension is set so as to form a margin.

  A plurality of oil grooves 16B and 16C for storing lubricating oil are provided on the outer peripheral side of the connecting pin 16 so as to extend in the axial direction. Each oil groove 16B located on the inner side in the left and right directions stores lubricating oil with the boss bush 13 and can communicate with each oil storage groove 13A and the through hole as shown in FIG. Yes. Thereby, the lubricating oil injected from the boss-side greasing hole 12B of the arm boss 12 flows into the oil groove 16B of the connecting pin 16 through the annular groove 13B and the through hole of the boss bush 13, and from the oil groove 16B to the boss The oil is supplied to each oil storage groove 13A of the bush 13 for use.

  On the other hand, each of the oil grooves 16C located on the outer side in the left and right directions stores lubricating oil between the bracket bush 15 and a cover bush 20 which will be described later, and covers the oil storage grooves 15A and 20A and the cover 17. It can communicate with the side greasing hole 17D. Thereby, the lubricating oil injected from the cover-side greasing hole 17D of the cover 17 flows into the oil groove 16C of the connecting pin 16, and the oil storage grooves 15A of the bracket bush 15 and the cover bush 20 of the cover bush 20 from the oil groove 16C. It is supplied to the oil storage groove 20A.

  Reference numeral 17 denotes left and right covers which are detachably provided on the outer end surface 14B of each bracket 14. The cover 17 prevents the connecting pin 16 that is movable in the axial direction by facing the protruding end portion 16 </ b> A of the connecting pin 16. Further, as shown in FIGS. 5 and 6, the cover 17 is formed as a thick disc body, and a shaft end accommodating recess 17B is formed on the abutting surface 17A side facing the outer end surface 14B. The shaft end accommodating recess 17B accommodates the protruding end 16A of the connecting pin 16, and is formed as a circular recess having substantially the same diameter as the pin insertion hole 14A of the bracket 14.

  Further, on the outer peripheral side of the cover 17, five bolt insertion holes 17 </ b> C are formed at predetermined intervals in the circumferential direction so as to correspond to the screw holes 14 </ b> C of the bracket 14. On the other hand, a cover-side greasing hole 17D is provided in the central portion of the cover 17 so as to penetrate in the axial direction. The cover-side greasing hole 17D is provided with lubricating oil for the bracket bush 15 and a cover bush 20 described later. Supply. Further, an annular seal groove 17E is formed on the contact surface 17A of the cover 17 so as to be located outside the shaft end accommodating recess 17B. A seal ring 18 is mounted in the seal groove 17E to seal the periphery of the shaft end accommodating recess 17B when the cover 17 is attached to the bracket 14.

  Then, the cover 17 is a fitting that has the contact surface 17A in contact with the outer end surface 14B of the bracket 14 with the seal ring 18 mounted in the seal groove 17E, and is inserted into each bolt insertion hole 17C in this state. The bolt 19 can be attached to the bracket 14 by being screwed into the screw hole 14 </ b> C of the bracket 14. In this mounting operation, the cover 17 can be easily positioned at a predetermined position by the protruding end portion 16A of the connecting pin 16.

  Reference numeral 20 denotes a cover bush provided in the shaft end accommodating recess 17 </ b> B of the cover 17. The cover bush 20 rotatably supports the protruding end 16 </ b> A of the connecting pin 16. Further, as shown in FIGS. 5 and 7, the cover bush 20 is formed as a short cylindrical slide bearing, and is fixedly fitted into the shaft end accommodating recess 17B using a means such as press fitting. Yes. Further, an oil storage groove 20A for storing lubricating oil is provided on the inner peripheral side of the cover bush 20, and the oil storage groove 20A is connected to the cover-side greasing hole of the cover 17 via the oil groove 16C of the connecting pin 16. It can communicate with 17D.

  Here, by providing the cover bush 20 in the shaft end accommodating recess 17 </ b> B of the cover 17, the connecting pin 16 can be inserted in a sliding state. Can do. Further, even when a load is applied to the cover 17 from the radial direction, the displacement of the cover 17 can be suppressed to a minimum, that is, within a minute gap size range.

  Reference numeral 21 denotes an O-ring that is fitted to the outer peripheral side of the arm boss 12 and the bracket 14 (see FIG. 3 and the like). The O-ring 21 is externally provided between the sliding surfaces of the arm boss 12 and the bracket 14. This prevents dust and the like from entering and prevents leakage of the lubricating oil.

  The bearing device 11 of the hydraulic excavator 1 according to the present embodiment has the above-described configuration, and when excavating the hydraulic excavator 1, the bucket 8 pin-coupled to the distal end side of the arm 7 via the bearing device 11 is A rotation operation is performed around the connecting pin 16 in accordance with the expansion and contraction operation of the bucket cylinder 9C.

  Further, during this excavation work, rocks or the like may collide with the cover 17 protruding outward. If the load due to the collision acts on the bolt 19 that attaches the cover 17 to the bracket 14, the bolt 19 may be damaged.

  However, according to the present embodiment, both end portions of the connecting pin 16 protrude in the axial direction from the outer end surface 14B of the bracket 14, and the cover 17 is provided with the protruding end portion 16A of the connecting pin 16. A shaft end receiving recess 17B for receiving is provided. Further, a cover bush 20 for rotatably supporting the protruding end portion 16A of the connecting pin 16 is provided in the shaft end accommodating recess 17B of the cover 17.

  Therefore, in the state where the protruding end portion 16A of the connecting pin 16 is inserted into the shaft end accommodating recess 17B of the cover 17 via the cover bush 20, a rock or the like collides with the cover 17 and a large load acts. This load can be received by the high-strength connecting pin 16 via the cover bush 20. Thereby, most of the load caused by the collision can be received by the connecting pin 16, so that the load acting on the bolt 19 can be reduced.

  As a result, the bolts 19 for attaching the cover 17 to the bracket 14 can be made thin or the number of the bolts 19 can be reduced. Therefore, the bearing device 11 can be reduced in size and weight, and the assembly workability can be improved. Can be improved.

  Further, in a state where the connecting pin 16 is inserted into the shaft end accommodating recess 17B (cover bush 20) of the cover 17, the cover 17 can be disposed concentrically with respect to the bracket 14, so the screw hole 14C of the bracket 14 and the cover The 17 bolt insertion holes 17C can be easily aligned, and the assembly workability can also be improved in this respect.

  In addition, by providing the cover bush 20 in the shaft end accommodating recess 17B of the cover 17, the cover 17 is prevented from rattling against the protruding end portion 16A of the connection pin 16 while allowing relative rotation of the connection pin 16. Can be installed on. Thereby, the load acting on the bolt 19 can be further reduced.

  On the other hand, since the oil grooves 16B and 16C are provided on the outer peripheral side of the connecting pin 16, lubricating oil is supplied to the boss bush 13, the bracket bush 15, and the cover bush 20 through the oil grooves 16B and 16C. And a smooth rotation operation can be maintained.

  Further, since the bolt 19 is used as an attachment for attaching the cover 17 to the bracket 14, the cover 17 can be easily attached to the outer end surface 14B of the bracket 14 by tightening or loosening the bolt 19 bolt. Can be removed.

  In the embodiment, the case where two boss bushes 13 are provided in the arm boss 12 so as to be separated in the left and right directions has been described as an example. However, the present invention is not limited to this. For example, one boss bush may be provided over the entire length of the arm boss 12, or three or more boss bushes may be provided.

  In the embodiment, the case where the cover 17 is configured to be attached to the bracket 14 using the five bolts 19 has been described as an example. However, the present invention is not limited to this. For example, the cover 17 may be attached to the bracket 14 using one to four, or six or more bolts 19. Further, the cover 17 may be attached to the bracket 14 using an attachment tool other than the bolt 19.

  On the other hand, in the embodiment, the case where the bearing device 11 is applied to the large excavator 1 is described as an example. However, the present invention is not limited to this, and the bearing device 11 may be applied to, for example, a medium-sized hydraulic excavator or a small-sized hydraulic excavator.

  Furthermore, in the embodiment, the case where the bearing device 11 is applied to the hydraulic excavator 1 has been described as an example. However, the present invention is not limited thereto, and other construction machines such as a hydraulic crane, a wheel loader, a bulldozer, and the like. You may apply to the pin coupling part.

5 Working device 7 Arm 8 Bucket 11 Bearing device 12 Arm boss (boss)
12A, 14A Pin insertion hole 13 Bushing bush 14 Bracket (mating member)
14B Outer end face 15 Bushing for bracket (Bushing for mating member)
16 connecting pin 16A protruding end 17 cover 17A contact surface 17B shaft end receiving recess 19 bolt 20 cover bush

Claims (2)

A cylindrical boss having a pin insertion hole extending in the axial direction, a boss bush provided in the pin insertion hole of the boss, and facing the pin in the axial direction and corresponding to the pin insertion hole A pair of counterpart members each having a pin insertion hole formed therein, a counterpart member bush provided in each pin insertion hole of the counterpart member, the boss bush, and the counterpart member bush. A connecting pin for connecting the boss and each counterpart member so as to be rotatable relative to each other, and an axially outer end face of each counterpart member so as to face the end of the connecting pin to prevent the connection pin from being removed. A bearing device comprising a cover,
Both ends of the connecting pin are provided to protrude in the axial direction from the outer end face of each counterpart member,
The cover is provided with a shaft end receiving recess for receiving the protruding end of the connecting pin,
A bearing device characterized in that a cover bush for rotatably supporting the protruding end portion of the connecting pin is provided in the shaft end accommodating recess of the cover.   The bearing device according to claim 1, wherein the cover is configured to be attached to an outer end surface of the counterpart member using a bolt.

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