JPH11141549A - Two-member coupling device of constrution machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance the sliding characteristics of a coupling part of a coupling pin constituting a two-member coupling device of a construction machine with a pin inserting hole provided on the bracket side. SOLUTION: An arm boss 17 furnished on the arm 9 side constituting a working device of a hydraulic shovel is coupled through a coupling pin 23 with brackets 21 and 22 furnished on the bucket 10 side, and one end of the pin 23 is secured to the brackets 21 and 22 through fastening bolt, 24, etc., in such a way that turning is prevented. Through a baking treatment, etc., molybdenum disulfide treatment layers 28 and 29 are formed over the whole circumference on the inside surfaces of pin inserting holes 21A and 22A provided in the buckets 21 and 22 to admit insertion of the coupling pin 23.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a two-member connecting device for a construction machine, which is suitably used as a bearing device in a construction machine such as a hydraulic shovel.

[0002]

2. Description of the Related Art Generally, in a construction machine such as a hydraulic excavator, for example, a boom, an arm, and a bucket of a working device are rotatably connected to each other by a bearing device as a two-member connecting device, thereby excavating earth and sand. The boom, the arm, and the bucket are extended and retracted (rotated) by extending and retracting the boom cylinder, the arm cylinder, and the bucket cylinder during operation.

[0003] Further, as the bearing device, for example, as described in Japanese Utility Model Application Laid-Open No. 8-105444, a boss provided on the distal end side of the arm and having a bush fitted on the inner peripheral side, and a bucket are provided. A pair of brackets provided so as to sandwich the boss from both sides in the axial direction, and a pin insertion hole as a pin hole, and slidably inserted into a bush, and both ends of the bracket The boss is constituted by a connecting pin or the like as a pin shaft rotatably connected between the brackets by being inserted into the insertion hole.

In this type of conventional bearing device, the relative rotation of the connecting pin with respect to each bracket is restricted by a rotation preventing means provided at one end side in the axial direction of the connecting pin, whereby each bucket is connected to the arm. When the bracket rotates on the front end side, each bracket rotates with respect to the boss together with the connection pin, and at this time, the connection pin and the bush slide with respect to each other.

In this prior art, when the connecting pin and the bush slide by impregnating the inner peripheral side of the bush with a high-viscosity lubricating oil, the lubricating oil is connected from the inner peripheral side of the bush by the friction heat. As a result, the lubrication between the sliding surface of the bush and the connecting pin is maintained without lubrication for a long time without lubrication.

[0006] The detent means includes a bolt insertion hole provided in both the bracket and the connection pin so as to penetrate a pin connection portion between the bracket and the connection pin, and is inserted into the bolt insertion hole. The connecting pin is secured to the bracket by engaging the fixing bolt integrated with the bracket into the bolt insertion hole on the connecting pin side. It is installed in the state where it was done.

[0007]

In the above-mentioned prior art, the bracket of the bucket is removed from the boss of the arm together with the connecting pin via the fixing bolt.
Attachments for other operations such as a crushing operation or a gripping / conveying operation are attached to the arm in addition to the bucket for the excavation operation.

Therefore, in the prior art, the hole diameter of the bolt insertion hole provided in the bracket and the connecting pin is intentionally set slightly larger than the fixing bolt to form the bolt insertion hole and the fixing bolt. By providing a gap between them, the work of inserting and removing the fixing bolt (detachment work) can be easily performed when the attachment is replaced.

However, if a gap is provided between the fixing bolt and the bolt insertion hole, rattling occurs between the fixing bolt and the bolt insertion hole, and during excavation work, every time the bucket is rotated, The bracket on the bucket side relatively rotates (oscillates) around the connection pin within a small angle range of about 3 to 4 degrees, and the pin insertion hole of the bracket and the connection pin slide repeatedly. become.

[0010] As a result, the microscopic metal contact at the contact portion (sliding portion) between the connecting pin and the pin insertion hole of the bracket easily causes galling or the like at the contact portion between the two, and this galling phenomenon occurs. Causes the generation of abnormal sounds such as squeaking noises, and has a problem of deteriorating the working environment.

Further, if the above-mentioned galling phenomenon expands (progresses) as it is, abnormal wear or deformation may occur between the contact surfaces of the connecting pins and the bracket, and in this case, the time for replacing parts is advanced, In addition to the cost of parts, there is a problem that the operation of the hydraulic excavator must be temporarily stopped every time parts are replaced, and the overall operation rate is reduced.

The present invention has been made in view of the above-mentioned problems of the prior art, and the present invention is based on the assumption that when a bracket and a boss are rotated relative to each other via a pin shaft, a pin hole of the bracket and a pin shaft are temporarily provided. Even if sliding occurs between them, the sliding performance at the contact portion between them can be improved, galling between these contact portions, abnormal wear, etc. can be prevented, and the life of components can be extended. In addition, an object of the present invention is to provide a two-member connecting device for a construction machine capable of maintaining a comfortable working environment by eliminating abnormal sounds such as squeaking noise.

[0013]

In order to solve the above-mentioned problems, a two-member connecting device for a construction machine according to the present invention comprises a bracket provided on one member constituting the construction machine and a boss provided on the other member. Are connected by a pin shaft, and the rotation of the pin shaft relative to the bracket is restricted by a detent means.

A feature of the structure adopted in the first aspect of the invention is that a treatment layer of a solid lubricant is formed on the bracket on the side of a pin hole through which a pin shaft is inserted.

With the above configuration, when the boss and the bracket are relatively rotated with respect to each other via the pin shaft, even if the bracket and the pin shaft are slightly rotated with each other via the rotation stopping means, The pin shaft can be slid with respect to the solid lubricant formed in the pin hole of the bracket, so that the sliding resistance between the bracket and the pin shaft can be reduced by the solid lubricant. Slidability can be maintained satisfactorily.

A feature of the structure adopted by the invention of claim 2 is that a treatment layer made of a solid lubricant is formed on the outer peripheral surface of the pin shaft facing the pin hole of the bracket.

With the above arrangement, when the boss and the bracket are relatively rotated with respect to each other via the pin shaft, even if the bracket and the pin shaft are slightly rotated relative to each other via the rotation stopping means, the pin shaft is not rotated. The pin shaft and the pin hole of the bracket can be slid with each other via the solid lubricant formed on the outer peripheral surface side of the bracket, whereby the sliding resistance between the bracket and the pin shaft can be reduced by the solid lubricant. As a result, it is possible to maintain good sliding characteristics at the contact portion between the two.

Further, a feature of the construction adopted by the invention of claim 3 is that the bracket is provided with a cylindrical slide bearing through which a pin shaft is inserted, and the slide bearing is provided with a solid lubricant on its inner peripheral side. That is, a layer is formed.

With the above arrangement, when the boss and the bracket are relatively rotated with respect to each other via the pin shaft, even if the bracket and the pin shaft are slightly rotated relative to each other via the rotation preventing means, the sliding bearing is provided. The pin shaft and the slide bearing can be slid with each other via the solid lubricant formed in the above. In addition, the sliding resistance between the slide bearing and the pin shaft can be reduced, and the sliding characteristics at the contact portion between the two can be maintained satisfactorily.

A feature of the construction adopted by the invention of claim 4 is that the bracket is provided with a cylindrical slide bearing through which a pin shaft is inserted, and the pin shaft has an outer peripheral surface facing the slide bearing. That is, a treated layer of a solid lubricant is formed on the side.

According to the above configuration, when the boss and the bracket are relatively rotated with respect to each other via the pin shaft, even if the bracket and the pin shaft are slightly rotated with each other via the rotation preventing means, the bracket can be rotated. The slide bearing inserted into the pin hole and the solid lubricant formed on the outer peripheral surface side of the pin shaft can be slid directly with each other, thereby reducing the sliding resistance between the slide bearing and the pin shaft by solid lubrication. It can be made smaller by the agent, and the sliding characteristics at the contact portion between the two can be maintained satisfactorily.

On the other hand, in the invention of claim 5, the treated layer of the solid lubricant is made of molybdenum disulfide.

Further, in the invention of claim 6, the treatment layer of the solid lubricant is made of at least one material of graphite, tungsten disulfide, boron nitride and carbon fluoride.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A two-member connecting device according to an embodiment of the present invention will be described below in detail with reference to the accompanying drawings, taking an example in which the present invention is applied to a pin connecting portion of a hydraulic shovel.

Here, FIGS. 1 to 5 show a first embodiment according to the present invention. In the drawing, reference numeral 1 denotes a lower traveling body of a hydraulic shovel, 2 denotes an upper revolving body mounted on the lower traveling body 1 so as to be pivotable, and the upper revolving body 2 has a revolving frame 3; Above the cab 4,
A machine room 5 and a counterweight 6 are provided.

Reference numeral 7 denotes a working device provided at the front of the upper swing body 2 so as to be able to move up and down. The working device 7 includes a boom 8 pin-connected to the swing frame 3 of the upper swing body 2 and the boom. An arm 9 is pin-coupled to the distal end of the arm 8, and a bucket 10 and the like are pin-coupled to the distal end of the arm 9. Brackets 21 and 22 to be described later are attached to the bucket 10 by means such as welding. And are provided integrally. The boom 8 of the working device 7 is raised and lowered by the boom cylinder 11, the arm 9 is raised and lowered by the arm cylinder 12 with respect to the boom 8, and the bucket 10 is moved by the bucket cylinder 13 with respect to the arm 9. It is turned.

The bucket cylinder 13 has a rod distal end connected to a pair of links 14 and 15 by pins, one of the links 14 and 15 is connected to a distal end of the arm 9 by pins, and the other link 15 Pins are connected to brackets 21 and 22 of the bucket 10. And
The bucket 10 is rotated via links 14 and 15 on the tip side of the arm 9 by extending and retracting a bucket cylinder 13.

Reference numeral 16 denotes a pin connecting portion between the tip end of the arm 9 and the brackets 21 and 22 of the bucket 10.
1 shows a bearing device as a member connecting device;
Reference numeral 6 includes an arm boss 17, brackets 21, 22 and connecting pins 23, which will be described later.

Reference numeral 17 denotes an arm boss as a boss portion integrally provided on the tip end side of the arm 9 by means of welding or the like. The arm boss 17 is formed in a substantially cylindrical shape from a metal material such as cast iron. The inner peripheral side is a bush fitting hole 17
A. In addition, annular tapered portions 17B, 1B are provided on both end surfaces in the axial direction of the arm boss 17 so as to be located on the outer peripheral side thereof.
7B are formed, and each of the tapered portions 17B is provided with a V together with tapered portions 21B and 22D of brackets 21 and 22 described later.
It forms a U-shaped groove.

Reference numeral 18 denotes a bush fitting hole 1 of the arm boss 17.
7A shows an oil-impregnated bush as a bush fitted in 7A. The oil-impregnated bush 18 is formed as a cylindrical body having a porous structure, for example, by a sintered alloy of iron and copper. The oil-containing bush 18 has a porosity of 5 to 30.
%, And a viscosity of, for example, 240
Lubricating oil consisting of gear oil or the like of about 1500 cSt is impregnated in advance.

The lubricating oil in the oil-containing bush 18 is
When the oil-impregnated bush 18 slides on the connection pin 23, the viscosity decreases due to the frictional heat, and the oil-impregnated bush 18 gradually exudes between the connection pin 23 and lubricates the sliding surface between the oil-impregnated bush 18 and the connection pin 23. It is configured to continue.

Reference numerals 19, 19 denote a pair of oil-shielding rings which are located on both axial sides of the oil-impregnated bush 18 and are fitted in the bush-fitting holes 17A of the arm bosses 17, respectively.
This is to prevent the lubricating oil from leaking to the outside from between the sliding surfaces of the oil-containing bush 18 and the connecting pin 23.

Numerals 20 and 20 denote dust seals which are located at both ends in the axial direction of the arm boss 17 and are fitted in the bush fitting holes 17A. As shown in FIG. Oil blocking rings 1 on both ends
9 to seal the space between the arm boss 17 and the connecting pin 23.

Reference numerals 21 and 22 denote left and right brackets projecting outside the bucket 10, respectively.
22, pin insertion holes 21A and 22A as pin holes at positions corresponding to the bush fitting holes 17A of the arm boss 17;
Are drilled. And the brackets 21 and 22
The arm boss 17 is disposed at both ends in the axial direction so as to sandwich the arm boss 17.

The right side bracket 22 of the brackets 21 and 22 is integrally formed with a cylindrical projecting portion 22B which is located on the opposite side to the arm boss and projects cylindrically from the outer edge of the pin insertion hole 22A. A bolt insertion hole 22C for a fixing bolt 24 to be described later penetrates the cylindrical protrusion 22B in the radial direction thereof. Further, the brackets 21 and 22 are formed with tapered portions 21B and 22D on the outer peripheral side of the end face facing the arm boss 17.

Reference numeral 23 designates the arm boss 17 as a bracket 21,
The connection pin 23 is a connection pin serving as a pin shaft rotatably connected between the connection pins 22. The connection pin 23 has an intermediate portion in the axial direction slidably inserted into the oil-containing bush 18, and both ends in the axial direction are brackets 21 and 22. Are inserted into the pin insertion holes 21A and 22A. Also, at the right end of the connecting pin 23,
Another bolt insertion hole 23A extending in the radial direction is formed corresponding to the bolt insertion hole 22C of the bracket 22.

Reference numeral 24 denotes a fixing bolt for restricting relative rotation of the connecting pin 23 with respect to the brackets 21 and 22. The fixing bolt 24 is provided in bolt insertion holes 22C and 23A between the bracket 22 and the connecting pin 23. And is fastened to the cylindrical projection 22B of the bracket 22 via the fixing nuts 25, 25. And the fixing bolt 24
Is inserted through the bolt insertion hole 23A of the connection pin 23 to prevent the connection pin 23 from being removed from the brackets 21 and 22 and to keep the connection pin 23 from rotating.

Here, the fixing bolt 24 has an outer diameter slightly smaller than the bolt insertion holes 22C and 23A. Thereby, a small gap (play) is provided between the fixing bolt 24 and the bolt insertion holes 22C and 23A,
When the fixing bolt 24 is removed or inserted from the inside of the bolt insertion holes 22C and 23A, the work of removing and inserting the fixing bolt 24 can be easily performed.

Reference numerals 26, 26 denote annular thrust plates disposed in the gaps between the arm boss 17 and the brackets 21, 22. As shown in FIG. It is formed as an annular thin plate from a lubricating metal material or a resin material, and a connection pin 23 is loosely fitted on the inner peripheral side thereof. The thrust plate 26 adjusts a gap between the arm boss 17 and the brackets 21 and 22 to suppress rattling between the two and to receive an external force acting between the two in the thrust direction.

Reference numerals 27, 27 denote O-rings for sealing between the arm boss 17 and the brackets 21, 22. The O-rings 27 are tapered portions 21B, 22D of the arm boss 17 and the brackets 21, 22, as shown in FIG. Is composed of V
Arm boss 1
Foreign matter between the bracket 7 and the brackets 21 and 22 is prevented, and the sliding surface between the arm boss 17 and the brackets 21 and 22 and each thrust plate 26 and the like are damaged by the foreign matter. Preventing.

Reference numerals 28 and 29 denote molybdenum disulfide (MoS2) -treated layers formed on the inner peripheral surfaces of the pin insertion holes 21A and 22B of the brackets 21 and 22, respectively. By means such as the above, it is integrally fixed to the inner peripheral surfaces of the pin insertion holes 21A and 22A over the entire circumference with a thickness of at least about 10 μm.

The molybdenum disulfide treated layer 28,
The baking process of 29 is performed by, for example, spraying powdery molybdenum disulfide on the inner periphery of the pin insertion holes 21A and 22A by spraying or the like, and then heating the brackets 21 and 22 in a furnace.

Then, the molybdenum disulfide treated layers 28, 2
9 has a so-called hexagonal crystal structure, and has a pin insertion hole 21.
A function as a solid lubricant that gives “fit-in” to the sliding between the pins A and 22A and the connecting pin 23 by being interposed between the pin inserting holes 21A and 22A and the connecting pin 23. The purpose of this is to reduce the sliding resistance.

The bearing device 16 according to the present embodiment has the above-described configuration, and its operation will be described below.

First, the bucket 10 shown in FIG.
When rotating with respect to the bracket 2 shown in FIG.
1 and 22 rotate with respect to the arm boss 17 together with the connecting pin 23, and at this time, the oil-containing bush 18 and the connecting pin 23 slide with each other.

Then, the temperature rises due to the frictional heat generated by the sliding, the viscosity of the lubricating oil in the oil-containing bush 18 decreases, and the lubricating oil gradually seeps between the oil-containing bush 18 and the connecting pin 23. It comes out. As a result, the connecting pin 2
The sliding surface between the oil-impregnated bush 18 and the oil-impregnated bush 18 is
The lubricating oil that oozes from inside 8 keeps the lubrication state for a long time.

When the bucket 10 is detached to attach another attachment such as a crushing work to the arm 9, first, the fixing bolt 24 is inserted through each fixing nut 25 into a bolt insertion hole between the bracket 22 and the connecting pin 23. 22
C, 23A, and then the connecting pin 23 is removed from the pin insertion holes 21A, 22A of the brackets 21, 22 so that the bucket 10 is removed from the arm boss 17 side of the arm 9 together with each O-ring 27 and each thrust plate 26. To do.

On the contrary, when the bucket 10 is mounted on the arm 9, first, the brackets 21 and 22 are arranged on both left and right sides of the arm boss so as to face each other.
Each thrust plate 26 between the arm boss 17 and the arm boss 17,
The connecting pin 23 is inserted into the pin insertion holes 21A and 22A with the respective O-rings 27 interposed therebetween. Then, the fixing bolt 24 is connected to the bracket 22 and the connecting pin 2.
3 is inserted into the bolt insertion holes 22C and 23A, and the fixing bolts 24 are inserted into the brackets 22 through the respective fixing nuts 25.
To connect the connecting pin 23 to the bracket 2.
The retainers 1 and 22 are kept in the retaining / rotating state.

Here, the fixing bolt 24 and the bolt insertion hole 2
Since a gap is intentionally provided between 2C and 23A, the work of attaching and detaching the fixing bolt 24 can be easily performed at the time of attaching and detaching the above-described bucket 10 and the like, thereby improving the overall work efficiency. be able to.

However, when a gap is provided between the fixing bolt 24 and the bolt insertion holes 22C and 23C, slight backlash occurs between the two, and the bucket 10 is rotated during excavation work or the like. Each time the bracket 21 or 22 is rotated, the brackets 21 and 22 relatively rotate (swing) about the connecting pin 23 within a minute angle range of about 3 to 4 degrees, and the connecting pin 23 and the pin insertion hole 21A are rotated. , 22A repeatedly slide with each other.

Here, as in the present embodiment, the connecting pins 2
3 is inserted into the pin insertion holes 21A and 22A of the brackets 21 and 22 via the molybdenum disulfide treated layers 28 and 29, and the molybdenum disulfide treated layers 28 and 29 are used as in the above-described conventional technique. The case where the connecting pin 23 is directly inserted into the pin insertion holes 21A and 22A without
An experiment for comparing the sliding characteristics (performance) between the pin insertion holes 21A and 22A of the brackets 21 and 22 and the connection pin 23 was performed using an experimental device shown in FIG.

The experimental apparatus includes a press 31, a motor 32, a torque measuring device 33 and the like installed on a base 30, and the press 31 has legs 34A, 34A on the base 30. A fixed base 34 is fixed, and a hydraulic ram 35 and the like fixed on the fixed base 34 are provided. The drive shaft 32A of the motor 32 has couplings 32B and 32B, and a torque measuring device 33 is provided between the couplings 32B. Further, the test piece 3 for the brackets 21 and 22 is provided on the press machine 31.
6 (36 ') and a test piece 37 for the connecting pin 23 are attached.

The test pieces 36 and 36 'are made of a rectangular plate having a pin insertion hole 36A formed at the lower end thereof. The axial length of the pin insertion holes 36A and 36A' is set to about 20 mm. I have. And the test pieces 36, 3
In the test piece 6 ', a treatment layer of molybdenum disulfide of about 50 μm is formed in advance on the inner peripheral surface side of the pin insertion hole 36A. On the other hand, the test piece 36 '
In this example, the above-described molybdenum disulfide treatment layer or the like is not formed in the pin insertion hole 36A, and the inner peripheral surface of the pin insertion hole 36 is exposed to the outside.

The test piece 37 is formed in a cylindrical shape from a carbon steel material for machine structural use (S45C) having an outer diameter of about 22 mm, and its outer peripheral side is subjected to induction hardening in advance. The test piece 37 is provided with a pin insertion hole 36A (36) of the test piece 36 (36 ').
A ') is slidably inserted in A'), and both ends are rotatably supported by the legs 34A of the fixed base 34. Lubricating oil is not sealed between the sliding surfaces of the test pieces 36 (36 ') and 37, and the two are maintained in a non-lubricated (dry) state. The test piece 37 has one end connected to the drive shaft 32A of the motor 32, so that the test piece 37 rotates integrally with the drive shaft 32A.

In this experimental apparatus, the upper end side of the test piece 36 (36 ') is pressed by the hydraulic ram 35, so that the sliding surface between the pin insertion hole 36A (36A') and the test piece 37 is formed. For example, the test piece 36 is rotated by the motor 32 at a peripheral speed of about 30 rpm and at regular intervals in the forward and reverse directions within a rotation angle range of about 2 degrees while a constant surface pressure of about 79 MPa is applied to the test piece 36. I do.

As a result, the test pieces 36 (36 ') for the brackets 21 and 22 are substantially equivalent to the state in which the test pieces 36 (36') for the connection pins 23 are moved up and down relatively at a small angle. . Then, in this state, the pin insertion hole 36A of the test piece 36 and the test piece 37
Is measured by a thermometer 38, and the measured friction heat is calculated as a friction coefficient μ between the test pieces 36 and 37.

As a result, as shown in FIG.
A characteristic diagram showing the relationship between the friction coefficient μ between (36 ′) and 37 and time was obtained.

Thus, in the test piece 36 'in which the molybdenum disulfide layer is not formed, as apparent from the characteristic line 39', the friction coefficient μ is reduced to about 1.0 within several hours from the start of the experiment. It was found that the temperature rose sharply, a galling phenomenon occurred, and the measurement became impossible.

On the other hand, in the test piece 36 on which the molybdenum disulfide layer was formed, as is clear from the characteristic line 39, the friction coefficient μ was 0.2 to 0 until about 9 hours had passed since the start of the experiment. It has been found that the size can be reduced to about 0.4. Also, after about 9 hours have elapsed from the start of the experiment, the friction coefficient μ gradually decreases with time, and when about 10 hours have elapsed, the friction coefficient μ is suppressed to about 0.1 or less, It turned out to be minimal.

After about 10 hours have passed,
The friction coefficient μ gradually increases with the passage of time.
After about 40 hours have passed since the start of the experiment, the friction coefficient μ gradually decreased again, and after about 45 hours, the size became about 0.4. It was found that it could be kept small.

Thus, according to the present embodiment, the molybdenum disulfide treated layers 28, 29 as a solid lubricant are formed on the inner peripheral surfaces of the pin insertion holes 21A, 22A over the entire circumference. Brackets 21 and 22 and connecting pin 23
Are rotated relative to each other, the connection pin 23 and the molybdenum disulfide-treated layer 2 on the pin insertion holes 21A and 22A side.
"Familiarity" can be given between the sliding surfaces with the sliding surfaces 8, 29, and the sliding resistance between the two can be greatly reduced.

Therefore, according to the present embodiment, when the bucket 10 is rotated, for example, the brackets 21 and 22 and the connecting pins 2
3 is slightly rotated relative to the bracket 2
1, 22 pin insertion holes 21A, 22A or connecting pin 2
3 can be prevented from being abnormally worn or deformed, the durability of the brackets 21 and 22 and the connecting pin 23 can be increased, the component replacement time can be extended, and the operating rate of the hydraulic shovel can be improved. . And the pin insertion hole 21A,
The occurrence of problems such as galling between the connecting pin 23A and the connecting pin 23 is suppressed.
Can be smoothly rotated relative to each other, and abnormal noise such as squeaking noise can be eliminated, and a comfortable working environment can be maintained for a long time.

Next, FIG. 6 shows a second embodiment according to the present invention. In this embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and description thereof will be given. It shall be omitted. However, the feature of the present embodiment is that the molybdenum disulfide treated layer 28, which is described in the first embodiment,
29, the connecting pin 2 facing the pin insertion hole 22A.
3 is that a molybdenum disulfide treatment layer 41 is formed on the outer peripheral surface side.

Here, the molybdenum disulfide treated layer 41
Is configured as a solid lubricant having a hexagonal crystal structure similarly to the molybdenum disulfide treated layers 28 and 29 described in the first embodiment. The molybdenum disulfide treated layer 41 is formed with a thickness of at least about 10 μm or more over the entire periphery of the connecting pin 23 facing the pin insertion hole 22A by means such as baking. I have.

Thus, also in the present embodiment configured as described above, the bracket 22 and the connecting pin 23 can slide with respect to each other via the molybdenum disulfide treatment layer 41. Almost the same operation and effect can be obtained.

Next, FIG. 7 shows a third embodiment according to the present invention. In this embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and description thereof will be given. Although omitted, the feature of this embodiment is that the bracket 2
The molybdenum disulfide treatment layer 51 is formed in the pin insertion hole 22A of No. 2 and the molybdenum disulfide treatment layer 52 is formed on the outer peripheral surface side of the connecting pin 23 facing the pin insertion hole 22A.

Here, the molybdenum disulfide treated layer 51
Is configured as a solid lubricant having a hexagonal crystal structure, similarly to the molybdenum disulfide treated layers 28 and 29 described in the first embodiment, and the pins of the bracket 22 are inserted through means such as baking. The hole 22A is formed on the inner peripheral surface over the entire periphery.

Also, the molybdenum disulfide treated layer 52 is substantially the same as
It is configured as a solid lubricant having a tetragonal crystal structure,
The connecting pin 23 is formed over the entire outer peripheral surface of the connecting pin 23 facing the pin insertion hole 22A by means such as printing.

Thus, also in the present embodiment configured as described above, the connecting pin 23 and the bracket 22 can be slid with each other via the molybdenum disulfide treatment layers 51 and 52, and the first embodiment is described. It is possible to obtain substantially the same operation and effect as the embodiment.

Next, FIG. 8 shows a fourth embodiment of the present invention. In this embodiment, the same reference numerals are given to the same components as those in the first embodiment, and the description will be given. It shall be omitted. However, a feature of the present embodiment is that a cylindrical sliding bearing 63 is provided on a bracket 62 of a bucket 10 which constitutes a part of a bearing device 61 as a two-member connecting device, and a connecting pin 23 is provided in the sliding bearing 63. In addition to the insertion, a molybdenum disulfide treatment layer 64 is formed on the inner peripheral surface side of the sliding bearing 63.

Here, the bracket 62 is connected to the first
Although it has substantially the same configuration as the bracket 22 described in the above embodiment and has a cylindrical projecting portion 62A, a bolt insertion hole 62B, and the like, the bracket 62 has a sliding bearing 6
A third bearing fitting hole 62C is formed.

The sliding bearing 63 is formed in a cylindrical shape from a hard metal material such as bearing steel.
Is fitted in the bearing fitting hole 62C. Further, other bolt insertion holes 63A, 63A are formed in the slide bearing 63 in the radial direction corresponding to the bolt insertion holes 23A, 62B of the connecting pin 23 and the bracket 62, and the respective bolt insertion holes are formed. A fixing bolt 24 is inserted into 23A, 62B and 63A.

Further, the molybdenum disulfide treated layer 64
Is formed as a solid lubricant having a hexagonal crystal structure, similarly to the molybdenum disulfide treated layers 28 and 29 described in the first embodiment, and is formed inside the sliding bearing 63 by means such as baking. It is formed over the entire circumference on the peripheral surface side.

Thus, in the present embodiment having the above-described structure, substantially the same operation and effect as those in the first embodiment can be obtained. When forming the molybdenum treatment layer 64, the slide bearing 63 is connected to the bearing fitting hole 6 of the bracket 62.
With the sliding bearing 63 removed in advance from the inside of the 2C, only the sliding bearing 63 can be placed in a furnace to perform the baking treatment of the molybdenum disulfide treated layer 64, thereby making it possible to perform the baking treatment as described in the first embodiment. It is not necessary to put the entire bracket 62 into the furnace, and the workability and the like at the time of the baking treatment of the molybdenum disulfide treated layer 64 can be improved.

Next, FIG. 9 shows a fifth embodiment according to the present invention. In the present embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof will be described. It shall be omitted. However, a feature of the present embodiment is that the connecting pin 23 is inserted into a slide bearing 63 provided on the bracket 62, and a molybdenum disulfide treated layer is formed on the outer peripheral surface side of the connecting pin 23 facing the slide bearing 63. 71 is formed.

Here, the molybdenum disulfide treated layer 71
Is made of a solid lubricant having a hexagonal crystal structure similarly to the molybdenum disulfide treated layers 28 and 29 described in the first embodiment. The molybdenum disulfide treatment layer 71 is fixed to the outer peripheral surface portion of the connection pin 23 facing the slide bearing 63 by means such as baking treatment over the entire circumference.

Thus, in the present embodiment having such a configuration, substantially the same operation and effect as those of the first embodiment can be obtained.

In the above embodiments, the processing layers 28 and 29 (4) made of molybdenum disulfide as a solid lubricant are used.
1, 51, 52, 64, 71), but instead, for example, graphite (C), tungsten disulfide (WS2), boron nitride (BN) or fluorocarbon ((CF) n ), A processing layer made of another solid lubricant having a hexagonal crystal structure is inserted into the pin insertion hole 21.
A, 22A (the connecting pin 23, the slide bearing 63) may be provided.

In the second, third and fifth embodiments, the molybdenum disulfide treated layer 41 (52, 71) is used.
Into the pin insertion hole 22A (61) of the bracket 22 (62).
Although described as being formed only on the outer peripheral surface side portion of the connecting pin 23 facing A), a configuration in which the molybdenum disulfide treated layer 41 and the like are formed on the entire outer peripheral surface of the connecting pin 23 may be used instead. .

Further, in each of the above embodiments, the molybdenum disulfide treated layers 28, 29 (41, 51, 52, 64,
71) are inserted into the pin insertion holes 21A, 21A of the brackets 21, 22.
2A (the connecting pin 23, the sliding bearing 63) is described as being fixed by means such as baking, but instead of this, for example, molybdenum disulfide treated layers 28, 29 (4
, 51, 52, 64, and 71) are composed of a plurality of small plates, and the molybdenum disulfide treated layer formed of the plates is connected to the inner peripheral surface side of the pin insertion holes 21A and 22A (the connection pins 23).
Of the sliding bearing 63). Furthermore, in each of the above embodiments,
Although the case where the bearing device 16 (61) as the two-member connecting device is used for the pin connecting portion between the arm 9 and the bucket 10 has been described as an example, the present invention is not limited to this. The bearing device 16 is connected to another pin connecting portion
(61) may be applied, or may be applied to a pin connecting portion provided in a construction machine such as a hydraulic crane or an agricultural or industrial working machine.

[0081]

As described above in detail, according to the first aspect of the present invention, the bracket and the boss are connected to each other via the pin shaft, and the rotation of the pin shaft relative to the bracket is stopped. In addition to the restriction by the means, the pin hole side of the bracket through which the pin shaft is inserted is formed with a solid lubricant treatment layer, so that when the bracket and the boss are rotated relative to each other, for example, Even if the pin shaft and the pin shaft are slightly rotated relative to each other via the rotation stopping means, at this time, the solid lubricant on the pin hole side and the pin shaft can be slid. In this way, it is possible to suppress the occurrence of malfunctions such as galling between the brackets and to smoothly rotate the bracket and the pin shaft relative to each other, thereby eliminating abnormal noises such as squeaking noises and improving the working environment. That.

Further, it is possible to prevent abnormal wear and deformation from occurring on the pin hole side or the pin shaft side of the bracket, to increase the durability of the bracket and the pin shaft and to extend the replacement time of parts, and Operation rate can be improved.

Further, according to the second aspect of the present invention,
Since the processing layer made of a solid lubricant is formed on the outer peripheral surface side of the pin facing the pin hole of the bracket, when the bracket and the boss are rotated relative to each other, for example, the bracket and the pin shaft rotate. Even if the pins are slightly rotated relative to each other via the stopping means, at this time, the pin holes and the solid lubricant treatment layer provided on the pin shaft side can be directly slid. It is possible to suppress the occurrence of a problem such as a galling phenomenon between the shaft and the shaft by the solid lubricant, to increase the durability of the bracket and the pin shaft, and to extend the replacement time of the parts. Similar effects can be obtained.

Further, according to the third aspect of the present invention, a structure in which a cylindrical slide bearing through which a pin is inserted is provided on the bracket, and a treated layer of a solid lubricant is formed on the inner peripheral side of the slide bearing. Therefore, when the bracket and the boss are relatively rotated with respect to each other, even if the bracket and the pin shaft slightly rotate relative to each other via the rotation stopping means, at this time, the solid lubricant provided on the slide bearing side is used. And the pin shaft can be slid, so that the solid lubricant can suppress the occurrence of a problem such as galling between the slide bearing and the pin shaft, and the bracket, the pin shaft and the slide bearing can be suppressed. Can be extended and the replacement time of parts can be extended, so that substantially the same effect as the first aspect of the invention can be obtained.

On the other hand, according to the fourth aspect of the present invention, the bracket is provided with the cylindrical slide bearing through which the pin is inserted.
Since a treatment layer of a solid lubricant is formed on the outer peripheral surface side of the pin facing the slide bearing, when the bracket and the boss are rotated relative to each other, the bracket and the pin shaft are prevented from rotating. Even if it rotates relatively slightly through the means, at this time, the sliding bearing and the solid lubricant provided on the pin shaft side can be slid directly, so that the galling between the sliding bearing and the pin shaft is also possible. The occurrence of problems such as phenomena can be suppressed by the solid lubricant, the durability of the bracket, the pin shaft and the slide bearing can be increased, and the replacement time of parts can be extended. Can be obtained.

Further, the treatment layer of the solid lubricant is made of at least one material of molybdenum graphite disulfide, tungsten disulfide, boron nitride and carbon fluoride. Thus, the sliding resistance between the pin shaft and the boss can be reliably reduced, and the same effect as the first aspect of the invention can be obtained.

[Brief description of the drawings]

FIG. 1 is an external view showing a hydraulic shovel to which a bearing device according to a first embodiment of the present invention is applied.

FIG. 2 is an enlarged longitudinal sectional view of the bearing device viewed from the direction of arrows II-II in FIG.

FIG. 3 is an enlarged view of a main part showing a bracket and a connecting pin in FIG. 2;

FIG. 4 is a schematic view showing an experimental device for measuring a coefficient of friction between a bracket and a connecting pin.

FIG. 5 is a characteristic diagram showing a relationship between a coefficient of friction between a bracket and a connecting pin and time when molybdenum disulfide is formed on a bracket and when molybdenum disulfide is not formed on the bracket.

FIG. 6 is an enlarged sectional view of a main part showing a bracket and a connecting pin of a bearing device according to a second embodiment of the present invention.

FIG. 7 is an enlarged sectional view of a main part showing a bracket and a connecting pin of a bearing device according to a third embodiment of the present invention.

FIG. 8 is a partially enlarged sectional view showing a bracket, a connecting pin, and a plain bearing of a bearing device according to a fourth embodiment of the present invention.

FIG. 9 is a partially enlarged sectional view showing a bracket, a connecting pin, and a plain bearing of a bearing device according to a fifth embodiment of the present invention.

[Explanation of symbols]

16, 61 Bearing device (two-member connecting device) 17 Arm boss 21, 22, 62 Bracket 21A, 22A Pin insertion hole (pin hole) 23 Connecting pin (pin shaft) 24 Fixing bolt (rotation stopping means) 28, 29, 41, 51, 52, 64, 71 Molybdenum disulfide treated layer 63 Plain bearing

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[Procedure amendment]

[Submission date] July 21, 1998

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0003

[Correction method] Change

[Correction contents]

[0003] As the bearing device, for example as described in Japanese open <br/> Rights 8-105444 discloses such a boss bush in circumferential side is provided is fitted to the distal end side of the arm are nip Muyo <br/> urchin arranged a boss provided on the bucket from both axial sides, a pair of brackets pin insertion hole of the pin hole is bored, slidably received within the bushing Each of the brackets includes a connecting pin as a pin shaft rotatably connecting the boss between the brackets by being inserted into the pin insertion holes of the brackets.

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0004

[Correction method] Change

[Correction contents]

[0004] In the bearing device according to the prior art of this type, the connecting pin relative to each bracket is limited by detent means provided on one axial end of the connecting pin to rotate relative, thereby, bucket an arm When the bracket rotates on the front end side, each bracket rotates with respect to the boss together with the connection pin, and at this time, the connection pin and the bush slide with respect to each other.

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] 0009

[Correction method] Change

[Correction contents]

[0009] However, in this way a gap is provided between the fixing bolt and the bolt insertion hole, rattling therebetween occurs only the gap amount, the excavation work or the like, each time rotating the bucket The bracket on the bucket side relatively rotates (swings) about the connecting pin within a small angle range of about 3 to 4 degrees, so that the pin insertion hole of the bracket and the connecting pin repeatedly slide with each other. I will be.

Claims (6)

[Claims] 1. A bracket provided on one member of a construction machine and a boss provided on the other member are connected by a pin shaft, and rotation of the pin shaft relative to the bracket is prevented by detent means. A two-member connecting device for a construction machine, wherein the bracket is provided with a solid lubricant treatment layer on a side of a pin hole through which a pin shaft is inserted. 2. A bracket provided on one member of a construction machine and a boss provided on the other member are connected by a pin shaft, and rotation of the pin shaft relative to the bracket is prevented by a rotation stopping means. A two-member connecting device for a construction machine, wherein a treatment layer made of a solid lubricant is formed on the outer peripheral surface of the pin shaft facing the pin hole of the bracket. apparatus. 3. A bracket provided on one member of the construction machine and a boss provided on the other member are connected by a pin shaft, and rotation of the pin shaft relative to the bracket is prevented by a rotation stopping means. In the two-member connecting device for a construction machine regulated, the bracket is provided with a cylindrical slide bearing through which a pin shaft is inserted, and the slide bearing has a solid lubricant treatment layer formed on an inner peripheral side thereof. A two-member connecting device for a construction machine, comprising: 4. A bracket provided on one member of the construction machine and a boss provided on the other member are connected by a pin shaft, and rotation of the pin shaft relative to the bracket is prevented by a rotation stopping means. In the two-member connecting device for a construction machine regulated, the bracket is provided with a cylindrical slide bearing through which a pin shaft is inserted, and the solid lubricant is provided on the outer peripheral surface side of the pin shaft facing the slide bearing. A two-member connecting device for construction machinery, wherein a treatment layer is formed. 5. The two-member connecting device for a construction machine according to claim 1, wherein the solid lubricant treatment layer is made of molybdenum disulfide. 6. The solid lubricant treatment layer according to claim 1, 2, 3, or 4, wherein the treatment layer is made of at least one of graphite, tungsten disulfide, boron nitride and carbon fluoride. Two-member connecting device for construction machinery.