JP2005048387A - Pin bearing structure of construction machinery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pin bearing structure of construction machinery without damaging a dust seal even if a burr-shaped projection occurs in the peripheral section of a pin hole in a fragile state. <P>SOLUTION: The construction machinery is so constituted that a circular space section 23 is formed on the end face of a boss section 12c opposed to the dust seal 22 provided on a pin connecting section 18 of a working machine 11 along the circumference of the a pin 20. Accordingly, the peripheral section of the pin hole 12d of the boss section 12c bearing both ends of the pin 20 becomes fragile by variable load repeatedly added to the pin 20 of the pin connecting section 18 during the work, and even if the burr-shaped projection 24 occurs in the peripheral section of the pin hole 12d toward the dust seal 22, since the front end of the burr-shaped projection 24 does not reach the dust seal 22 by providing the space section 23, the dust seal 22 can be prevented from being damaged by the burr-shaped projection 24. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a pin bearing structure of a pin coupling portion provided in a working machine of a construction machine.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, a work machine mounted on a construction machine such as a hydraulic excavator is provided with a plurality of pin coupling portions between members constituting the work machine.
The working machine in the case of a hydraulic excavator has a structure in which one end of an arm is pivotally attached to the tip of a boom whose base end is pivotally attached to the upper swing body, and a bucket is pivotally attached to the other end of the arm. In addition, a pin coupling portion is adopted for each pivot attachment portion.
[0003]
In addition, as shown in FIG. 8, the pin coupling portion of the conventional working machine has a boss c formed at the tip of a bifurcated bracket b protruding from the end of one member a, and this boss c A boss portion e of the other member d is pivotally attached by a pin f, and a bush g made of an abrasion-resistant material is interposed between the inner peripheral surface of the boss portion e and the outer peripheral surface of the pin f. In addition, between the end surface of the bush g and the inner surface of the bracket b-side boss portion c, for example, as described in Patent Document 1, dust or the like is externally applied to the sliding surface of the bush g and the pin f. A dust seal h that prevents further intrusion is provided.
[0004]
[Patent Document 1]
Japanese Utility Model Publication No. 6-1925
[Problems to be solved by the invention]
However, since work machines installed in construction machines work under harsh conditions, excessive loads are often repeatedly applied to the pin joint during work, and in particular, excessive bias loads are applied to the pin joint. When a bending load is applied, the pin f bends substantially in a U-shape due to an excessive load as shown in FIG. 9, so that the inner end face and the outer end face shown by the arrows of the boss part c supporting both ends of the pin f As shown in FIG. 10, the peripheral portion of the pin hole i sticks to the peripheral portion of the pin hole i, and as a result, a burr-like protrusion j is generated in the peripheral portion of the pin hole i.
The burr-like protrusion j generated on the outer end surface of the boss part c is not particularly problematic. However, the burr-like protrusion j generated on the inner end face of the boss part c is formed between the bush g and the inner end face of the boss part c. The dust seal h interposed therebetween is damaged, or the end surface of the boss part c is damaged.
When the dust seal h is damaged, the sealing effect is remarkably reduced, so that dust or the like enters the sliding surface of the bush g and the pin f from the outside, or lubricating oil such as grease filled in the sliding surface leaks out. As a result, there are problems such as abnormal wear on the sliding surface and seizure.
[0006]
The present invention has been made to remedy such a conventional problem, and has a pin bearing structure for a construction machine that does not damage the dust seal even if the peripheral portion of the pin hole is loose and a burr-like protrusion is generated. It is intended to provide.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, a pin bearing structure for a construction machine according to the present invention includes a plurality of members constituting a work machine, and a boss portion provided in the member adjacent to a boss portion provided at an end portion of these members. A pin that is inserted to pivotally connect the two members, a dust seal disposed on an outer peripheral portion of the pin on one side of the boss portion, and one member on the side where the dust seal is disposed are adjacent to the pin. A pin bearing structure of a construction machine configured to be rotatable with respect to a member, on an inner wall portion in contact with an outer peripheral portion of the pin at the other end portion of the boss portion of the adjacent member, on an outer periphery of the pin An annular space is formed along the space, and the space is formed to face the dust seal.
[0008]
Due to the above-described structure, during work on the work machine, the boss part that supports both ends of the pin due to repeated load or bending load that is repeatedly applied to the pin causes settling around the pin hole, and the peripheral part of the pin hole has a burr toward the dust seal. Even if a protrusion is generated, a space is formed in advance on the inner end surface of the boss that faces the dust seal, so that the burr-like protrusion generated on the periphery of the pin hole protrudes into this space. However, since the tip does not reach the dust seal, it is possible to prevent the dust seal from being damaged by the burr-like projection.
This prevents dust and the like from entering the sliding surface of the pin coupling portion from the outside, and prevents lubricating oil such as grease filled in the sliding surface from leaking to the outside. It will be possible to prevent seizure.
[0009]
In order to achieve the above object, the pin bearing structure of the construction machine according to the present invention is such that the inner diameter of the space portion is equal to or slightly larger than the outer diameter of the dust seal.
[0010]
According to the above configuration, since the protrusion margin of the burr-like protrusion can be increased, it is possible to prevent the dust seal from being damaged by the burr-like protrusion over a long period of time.
[0011]
In order to achieve the above object, the pin bearing structure of the construction machine according to the present invention forms a space portion by making the inner diameter of the plate fixed to the end face of the boss portion equal to or slightly larger than the outer diameter of the dust seal. It is a thing.
[0012]
With the above configuration, the space can be easily and inexpensively formed by simply processing the inner diameter of the plate body for adjusting the gap between the members to be equal to or slightly larger than the outer diameter of the dust seal. Can be formed.
In order to achieve the above object, the pin bearing structure of the construction machine according to the present invention is such that a space portion is formed by chamfering the opening edge of the pin hole drilled in the boss portion or processing it into an R shape.
[0013]
With the above configuration, the space portion can be formed by simply chamfering the opening edge of the pin hole or processing it into an R shape, so that it can be easily implemented in a working machine of an existing construction machine.
[0014]
In order to achieve the above object, a pin bearing structure for a construction machine according to the present invention includes a self-propelled lower traveling body, an upper revolving body that is pivotably installed on the lower traveling body, and a front portion of the upper revolving body. Inserted into a boss portion provided on the member adjacent to a boss portion provided at an end portion of these members, a plurality of members constituting the work device, and a plurality of members constituting the work device. A pin that is movably connected, a dust seal disposed on an outer peripheral portion of the pin on one side of the boss portion, and one member on the side on which the dust seal is disposed can be rotated with respect to the adjacent member. A pin bearing structure of a constructed construction machine, wherein an annular space portion is formed along an outer periphery of the pin in an inner wall portion in contact with an outer peripheral portion of the pin at the other end portion of the boss portion of the adjacent member. And the space Are those formed so as to face the dust seal.
[0015]
Due to the above-described structure, during work on the work machine, the boss part that supports both ends of the pin due to repeated load or bending load that is repeatedly applied to the pin causes settling around the pin hole, and the peripheral part of the pin hole has a burr toward the dust seal. Even if a protrusion is generated, a space is formed in advance on the inner end surface of the boss that faces the dust seal, so that the burr-like protrusion generated on the periphery of the pin hole protrudes into this space. However, since the tip does not reach the dust seal, it is possible to prevent the dust seal from being damaged by the burr-like projection.
This prevents dust and the like from entering the sliding surface of the pin coupling portion from the outside, and prevents lubricating oil such as grease filled in the sliding surface from leaking to the outside. In addition to preventing seizure, the inner diameter of the space is the same as or slightly larger than the outer diameter of the dust seal. It is possible to prevent the dust seal from being damaged by the protrusion.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment in which the present invention is implemented in a hydraulic excavator will be described in detail with reference to the drawings.
1 is a side view of the hydraulic excavator, FIG. 2 is a cross-sectional view taken along the line AA in FIG. 1, FIG. 3 is an enlarged view in a circle B in FIG. 2, and FIG.
[0017]
The hydraulic excavator shown in FIG. 1 is composed of a self-propelled lower traveling body 1 and an upper revolving body 2 installed on the lower traveling body 1 so as to be able to swivel.
The lower traveling body 1 has a track frame 3 including a center frame 3a and a pair of side frames 3b provided on both sides of the center frame 3a. An idler 4 is provided at one end of each side frame 3b. A sprocket 6 that is supported by a traveling motor 5 that is a hydraulic motor is provided on the other end side.
[0018]
An endless crawler belt 7 is provided between the idler 4 and the sprocket 6, and by driving the crawler belt 7 with the sprocket 6, the lower traveling body 1 can self-propel and the side frame A plurality of rolling wheels 8 are rotatably supported on the upper and lower portions of 3b.
The upper swing body 2 that is pivotably installed on the center frame 3 a of the track frame 3 is configured by a body frame 10 at the bottom, and a work machine 11 configured by a plurality of members is attached to the body frame 10. Has been.
[0019]
A driver's cab 30 is installed at the front of the vehicle body frame 10 on the side of the work implement 11, and an engine compartment 31 covered with a bonnet cover 31a is installed at the rear of the vehicle body frame 10, A power engine (not shown) is accommodated in the engine chamber 21, and a counterweight 32 is attached to the rear end of the vehicle body frame 10.
[0020]
As shown in FIG. 1, the work machine 11 has a base end pivotally attached to the body frame 10 and a boom 12 that can be raised and lowered by a boom cylinder 13, and a base end side pivotally attached to the tip of the boom 12. 14 is composed of a plurality of members each consisting of an arm 15 that is rotatable by 14 and a bucket 17 that is pivotally attached to the tip of the arm 15 and that is rotatable by a bucket cylinder 16. The pin coupling portion 18 for pivotally attaching one end of the arm 15 has a pin bearing structure as shown in FIG.
That is, a bracket 12a which is bifurcated is protruded from the tip of the boom 12, and the tip of the bracket 12a is slightly thick. An annular plate 12b is welded to both sides of these thick parts. By fixing by means, a boss 12c is formed at the tip of the bracket 12a.
The plate body 12b fixed to the inside of the bracket 12a has a shim function for adjusting the gap between the bracket 12a and the arm 15, and the plate body 12b whose thickness is previously selected according to the gap is the thick portion. It is fixed inside.
The boom 12 side boss portion 12c has a pin hole 12d on the same axis, and one end of the arm 15 is fitted between the boss portions 12c.
Boss portions 15a are formed on one end side of the arm 15, and the outer end surfaces of these boss portions 15a are in sliding contact with the inner end surface of the boom 12 side boss portion 12c, and the inner end surfaces of the boss portions 15a are The both ends of the cylindrical spacer 15b are welded.
[0021]
Each boss portion 15a on the arm 15 side is provided with a pin hole 15c at a position matching the pin hole 12d of the boom 12 side boss portion 12c.
These pin holes 15c have a slightly larger diameter than the pin hole 12d of the boss portion 12c on the boom 12 side, and a cylindrical bush 19 made of a wear-resistant material is press-fitted into the inner peripheral surface of the pin hole 15c. At the same time, the boom 12 and the arm 15 are pivotally mounted by a pin 20 inserted into the bush 19 through the pin hole 12c of the boom 12 side boss portion 12b.
The pin 20 that couples the boom 12 and the arm 15 has a head portion 20a having a slightly larger diameter on one end side, and a pin hole 20b is formed on the other end side. The pin 20 is locked so as not to come out by a locking pin 21a inserted into the pin hole 20b from a locking ring 21 fixed to the outer surface.
[0022]
Between the outer end surface of the bush 19 press-fitted into the pin hole 15c of the boom 12 side boss portion 15a and the inner end surface of the boom 12 side boss portion 12b, dust or the like is applied to the sliding contact surface of the bush 19 and the pin 20 from the outside. The dust seal 22 is fitted to prevent the lubricating oil such as grease filled in the sliding contact portion from leaking to the outside while preventing the intrusion.
The dust seal 22 is formed in an annular shape by an elastic body such as rubber having oil resistance, and a lip (not shown) that is in contact with the inner peripheral surface is pressed against the outer peripheral surface of the pin 20 to prevent intrusion of dust or the like. It prevents the leakage of lubricating oil.
A space 23 that prevents the dust seal 22 from being damaged is formed at a position facing the dust seal 22 on the inner end face of the boom 12 side boss portion 12b.
As shown in FIG. 3, the space 23 is formed by setting the inner diameter of the plate 12 b forming the inner side of the boom-side boss 12 c to be equal to or slightly larger than the outer diameter of the dust seal 22. It is formed in an annular shape along the outer peripheral surface, and the width W is the thickness of the plate body 12b. Due to this width W, a burr-like protrusion 24 generated around the pin hole 12d of the boom 12 side boss portion 12c. Even if it protrudes toward the dust seal 22, the tip of the protrusion 24 does not reach the dust seal 22.
[0023]
Next, the operation of the pin bearing structure of the construction machine constructed as described above will be described.
Most of the work by the work machine 11 mounted on the hydraulic excavator is excavation work, but the tip of the bucket touches the rock during excavation work, or the pin coupling portion between the arm 15 and the boom 12 during excavation work such as rock An excessive load acts on 18.
Due to an excessive load acting on the pin coupling portion 18 during the operation, an eccentric load and a bending load are repeatedly applied to the pin 20 that pivotally attaches the arm 15 and the boom 12, so that the pin 20 is bent in an arch shape by these loads. When the arm 15 and the boom 12 rotate relative to each other in this state, the boom 12 side boss portion 12c that supports both ends of the pin 20 is set at the periphery of the pin hole 12d, as shown in FIG. In addition, a burr-like protrusion 24 is generated toward the dust seal 22 around the pin hole 12d.
[0024]
However, since an annular space portion 23 is formed in advance between the inner end face of the boss portion 12c on the boom 12 side and the dust seal 22, the burr-like protrusion 24 generated in the peripheral portion of the pin hole 12d However, the dust seal 22 can be prevented from being damaged by the burr-like protrusions 24 since the tip does not reach the dust seal 22.
As a result, dust or the like enters the sliding surface of the bush 19 and the pin 20 press-fitted into the pin hole 15c of the arm 15 side boss portion 15a from the outside, or lubricating oil such as grease filled in the sliding surface is exposed to the outside. Since the leakage can be prevented, the sliding surface can be prevented from being abnormally worn or seized.
Further, the inner space of the plate body 12b having a shim function for adjusting the gap between the boom 12 side boss portion 12c and the arm 15 side boss portion 15a is made equal to or slightly larger than the outer diameter of the dust seal 22 to form a space portion. 23, the load acting on the pin 20 is not directly applied to the plate body 12b, so that the welded portion of the plate body 12b or the plate body 12b itself is prevented from being damaged by an excessive load. You can also
[0025]
In the above-described embodiment, the case of the working machine 11 in which the boss portion 12c is formed by welding the plate body 12b to the bracket 12a of the boom 12 has been described. However, as in the modification shown in FIGS. The same can be applied to a case in which the bracket 12a and the boss portion 12c are integrally formed of cast steel or the like.
In the modification shown in FIG. 5, an annular space 23 having a diameter substantially equal to or slightly larger than the outer diameter of the dust seal 22 is opposed to the dust seal 22 on the inner end surface of the boss portion 12 c integrated with the bracket 12 a. Is formed.
Further, in the modification shown in FIG. 6, the space portion 23 is formed on the surface facing the dust seal 22 by chamfering the opening edge of the pin hole 12 d opened on the inner end surface of the boss portion 12 c integrated with the bracket 12 a. In any of the modifications, the burr-like protrusion 24 generated by the peripheral portion of the pin hole 12d is bulged in the space portion 23, but the tip reaches the dust seal 22 in the same manner as in the above embodiment. Therefore, it is possible to prevent the dust seal 22 from being damaged by the burr-like protrusions 24.
[0026]
On the other hand, the modification shown in FIG. 7 shows an example in which the boss portion 12c is welded to the bracket 12a of the boom 12, and this modification will be described next.
In this modification, one of the boss portions 12c is formed by a plate body 12f welded to both sides of one bracket 12a, and the other boss portion 12c is welded to the inside of the other bracket 12a. The boss portion 15a on the arm 15 side is coupled by a pin 20 inserted through the pin hole 12d of the portion 12c.
A spacer 25 is interposed between one of the boom 12 side boss part 12c and one of the arm 15 side boss part 15a, and a gap adjusting shim 26 is interposed between the spacer 25 and the boom 12 side boss part 12c. Has been.
A plurality of shims 26 are prepared in advance, and when the gap becomes large due to wear, the gap can be readjusted by replacing the spare shim 26a with the spare shim 26a. The boom 12 side boss portion 12c is stored in a state of being tightly attached between the end plate 28 attached to the outer end surface of the boom 12 side boss portion 12c and the boss portion 12c.
[0027]
A space 23 is formed on one end surface of the boom 12 side boss portion 12 c provided so as to be in sliding contact with the outer end surface of the arm 15 side boss portion 15 a and the end surface of the spacer 25 so as to face the dust seal 22.
These space portions 23 are also substantially the same as or slightly larger in diameter than the dust seal 22, and the peripheral portion of the pin hole 12 d formed in the boom 12 side boss portion 12 c, as in the above-described embodiment and modification. Although the burr-like protrusion 24 generated by the stagnation protrudes into the space portion 23, the tip does not reach the dust seal 22, so that the dust seal 22 is prevented from being damaged by the burr-like protrusion 24 in advance. can do.
In the above-described embodiment and modification, the case where the boom 12 and the arm 15 are pivotally connected to the pin coupling portion 18 has been described. However, between the base end portion of the boom 12 and the upper swing body 2, The same can be applied to the pin coupling portion between the tip and the bucket 17.
[0028]
【The invention's effect】
As described in detail above, the present invention forms an annular space along the outer periphery of the pin on the end surface of the boss portion facing the dust seal provided in the pin coupling portion of the work machine. Even if a biased load is applied to the pin repeatedly due to uneven load or bending load applied to the pin, the boss part supports both ends of the pin hole. Since a space portion is formed in advance on the inner end surface of the boss portion facing the dust seal, the burr-like protrusions generated in the peripheral portion of the pin hole protrude into the space portion, but the tip reaches the dust seal. Therefore, it is possible to prevent the dust seal from being damaged by the burr-like protrusion.
This prevents dust and the like from entering the sliding surface of the pin coupling portion from the outside, and prevents lubricating oil such as grease filled in the sliding surface from leaking to the outside. In addition to preventing seizure, the inner diameter of the space is the same as or slightly larger than the outer diameter of the dust seal. It is possible to prevent the dust seal from being damaged by the protrusion.
[Brief description of the drawings]
FIG. 1 is a side view of a construction machine adopting a pin bearing structure according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view taken along line AA in FIG.
FIG. 3 is an enlarged view within a circle B in FIG. 2;
FIG. 4 is an operation explanatory view of the pin bearing structure of the construction machine according to the embodiment of the present invention.
FIG. 5 is a sectional view showing a modification of the pin bearing structure of the construction machine according to the embodiment of the present invention.
FIG. 6 is a sectional view showing a modification of the pin bearing structure of the construction machine according to the embodiment of the present invention.
FIG. 7 is a sectional view showing a modification of the pin bearing structure of the construction machine according to the embodiment of the present invention.
FIG. 8 is a cross-sectional view showing a pin bearing structure of a conventional construction machine.
FIG. 9 is an operation explanatory diagram of a conventional pin bearing structure of a construction machine.
FIG. 10 is an operation explanatory view of a conventional pin bearing structure of a construction machine.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Lower traveling body 2 Upper revolving body 11 Work implement 12c Boss part 12b Plate body 12d Pin hole 15a Boss part 18 Pin coupling part 20 Pin 22 Dust seal 23 Space part

Claims (5)

A plurality of members constituting the work machine, pins inserted into the boss portions provided in the members adjacent to the boss portions provided at the end portions of these members, and the members movably connected to each other; and the bosses A pin seal structure of a construction machine in which the dust seal disposed on the outer peripheral portion of the pin on one side of the part and the one member on the side on which the dust seal is disposed are configured to be rotatable with respect to the member adjacent thereto. An annular space portion is formed along an outer periphery of the pin on an inner wall portion in contact with the outer periphery portion of the pin at the other end portion of the boss portion of the adjacent member, and the space portion is the dust seal. A pin bearing structure for a construction machine, characterized in that it is formed so as to be opposed to the machine. The pin bearing structure for a construction machine according to claim 1, wherein an inner diameter of the space portion is formed to be equal to or slightly larger than an outer diameter of the dust seal. The pin bearing of the construction machine according to claim 1, wherein the space portion is formed by setting the inner diameter of the plate fixed to the end face of the boss portion to be equal to or slightly larger than the outer diameter of the dust seal. Construction. The pin bearing structure for a construction machine according to claim 1 or 2, wherein the space portion is formed by chamfering an opening edge of a pin hole drilled in the boss portion or processing it into an R shape. A self-propelled lower traveling body, an upper revolving body that is pivotably installed on the lower traveling body, a working machine mounted on a front portion of the upper revolving body, and a plurality of members constituting the working machine A pin that is inserted into a boss provided in the member adjacent to the boss provided at the end of these members and rotatably connects the two members, and the pin on one side of the boss A pin bearing structure for a construction machine in which a dust seal disposed on an outer peripheral portion and one of the members on the side where the dust seal is disposed are configured to be rotatable with respect to the adjacent member. An annular space portion is formed along the outer periphery of the pin on the inner wall portion in contact with the outer periphery portion of the pin at the other end portion of the boss portion, and the space portion is formed so as to face the dust seal. Features Pin bearing structure of the construction machine.

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