KR100655327B1 - Arrangement for connecting joint part in construction machinery - Google Patents

Abstract

The present invention relates to a joint structure of the construction machine. The joint connection structure of the present invention includes a first member having a pair of support plates having pin holes, a second member disposed between the support plates and having pin holes, and pin holes of the support plates aligned with each other. A pin inserted into a pin hole of two members and fixed to a support plate at both ends thereof, and a bush disposed between the circumference of the pin and the pin hole of the second member, and the pin has a hollow having an inner diameter for storing lubricant therein. And a lubricant feeding means for feeding the lubricant stored in the inner diameter between the pin and the bush and between the bush and the pin hole of the second member, wherein the plurality of the lubricant feeding means are radially formed on the pin so as to communicate with the inner diameter. The communication passage formed in the bush so as to communicate with the lubricating oil feeding hole, the lubricating oil feeding hole, and the lubricating oil introduced into the communication passage between the pin and the bush, and the bush and the A lubricating oil feeding groove is formed around the inner and outer diameters of the bush so as to feed between the two members. According to the present invention, after the pin is hollowed and the lubricant is filled in the inside of the hollowed pin, the filled lubricant is fed between the pin hole and the pin and the bush so that the pin is not fed for a long time without additional feeding. Friction between the pinhole and the pin hole can be reduced. In addition, it is possible to reduce the weight by hollowing the pin to reduce the weight, thus improving the dynamic stability and durability.

Description

Joint structure of construction machine {ARRANGEMENT FOR CONNECTING JOINT PART IN CONSTRUCTION MACHINERY}

1 is a cross-sectional view showing a joint structure of the construction machine according to the invention,

2 is an enlarged cross-sectional view of a portion “A” in FIG. 1;

3 is an enlarged cross-sectional view of a portion “B” in FIG. 1.

♣ Explanation of symbols for the main parts of the drawing ♣

10: first member 10a: support plate

12: pinhole 20: second member

22: pinhole 30: pin

30a: coating layer 32: inner diameter

34: outer diameter 38: cap

38a: injection hole 38b: vent hole

40: bush 40a: inner diameter

40b: Outer diameter 42: Dust seal

60: spacer 70: lubricating oil supply means

72: lube oil supply hole 74: communication path

76: lubricant feed groove

The present invention relates to a joint connecting structure of a construction machine, and more particularly to a joint connecting structure of a construction machine for jointly connecting two members.

Construction machinery such as excavators, skid steer loaders and the like have a number of joints, for example, boom and arm connections, arm and bucket connections, and the like. These joints are generally formed by forming pinholes in two members (hereinafter, referred to as "first member and second member") that require joint motion, and then inserting the pins into pinholes aligned with each other so that the joint motion is improved. Make it happen. Here, a bush, a spacer, and the like are disposed around the pin between the first and second members of the joint part to reduce the frictional resistance generated between the pin and the pin hole.

On the other hand, there is a feeding hole for lubricating oil in each of the joints so that the lubricating oil can be supplied, and regular lubricating oil is supplied through the feeding hole. However, it is necessary to replenish lubricating oil regularly due to the outflow of lubricating oil by high load and low speed friction and the loss of lubricating oil due to heat. Therefore, if the feeding period is injected repeatedly every day, the surface of the vehicle becomes very dirty and harmful to the environment, and the frequent use of lubricating oil increases the amount of lubricating oil, which leads to an increase in maintenance costs and the inability to work during the lubricating oil feeding time. The utilization rate drops. In addition, when the lubricating oil is not inadvertently introduced by the operator, abnormal wear occurs between the bush and the pin due to dry friction of the joint, and the entire structure needs to be replaced due to the wear of the first and second members. do.

On the other hand, the pin of the joint portion of the conventional construction equipment, to facilitate the injection of lubricating oil, as in the Patent Registration No. 10-0389935, to form a lubricating oil supply passage in the pin, and to the outside of the fin supplied to the pipeline The lubricating oil groove is formed so that the supplied lubricating oil can be supplied to the sliding part in frictional contact with the bush.

By the way, such a lubricating oil groove has a high possibility that the pin is broken because the pin acts as a stress concentration part when a bending load or an impact load is applied. In addition, in the case of using a copper alloy or oilless-containing sintered bearing, which is relatively softer than the pin, as the counter bush, the groove of the pin can act as a cutting edge for abrasion of the bush, thereby promoting the wear of the counter bush. In addition, there is a risk of breakage due to lubricating oil pipes and grooves acting as stress concentration parts when excessive bending and impact loads are applied during construction work. There is a problem that is generated to reduce the life of the pin.

In addition, the friction between the pin and the bush and the side load acts at the same time the friction is generated, the first member, the second member and the pin in order to reduce the side friction contact between each part and to control the gap between each part Spacers or shims are disposed between them. Spacer or shim is used by inserting the steel sheet as the gap. By the way, such a spacer or shim has a problem that sintering and wear occurs due to the side frictional contact between the parts.

Therefore, the present invention has been made to solve the conventional problems as described above, the object is to hollow the pin, and after filling the lubricating oil inside the hollowed pin, the filled lubricating oil and the pinhole and the pin It is provided to be provided between the bushes to provide a joint structure of the construction machinery that does not require additional feeding for a long time.

It is another object of the present invention to provide a joint structure of a construction machine, in which durability is improved and life is extended by reducing frictional contact between a pin and a pin hole even in an extended state of supplying lubricant.

Another object of the present invention is to provide a joint structure of the construction machine that can be lightened by reducing the weight by hollowing the pin, and thus can improve the dynamic stability and durability.

In order to achieve the above object, the joint structure of the construction machine according to the present invention, the first member having a pair of support plates with a pin hole, and the second having a pin hole disposed between the support plates A member disposed between the member, the pin hole of the support plate aligned with each other, and the pin hole of the second member, and both ends of which are fixed to the support plate, and a bush disposed between the circumference of the pin and the pin hole of the second member. In the joint structure of the construction machine provided with the pin, the pin is a hollow body having an inner diameter on both sides so as to store the lubricating oil, both sides of the inner diameter are sealed by a cap, of the two caps One is formed with an injection hole for injecting lubricating oil into the inner diameter, the other is formed with a vent hole through which air of the inner diameter can escape And lubricating oil feeding means for feeding lubricating oil stored in the inner diameter between the pin and the bush and between the bush and the pin hole of the second member, wherein the lubricating oil feeding means is radially connected to the pin so as to communicate with the inner diameter. A plurality of lubricating oil feeding holes formed in the plurality of lubricating oil holes, a communicating flow path formed in the bush so as to communicate with the lubricating oil feeding hole, and lubricating oil introduced into the communicating flow path between the pin and the bush, and between the bush and the second member. It is characterized by consisting of a lubricating oil feeding groove formed around the inner diameter and outer diameter of the bush so as to feed between.

Hereinafter, a preferred embodiment of the joint structure of the construction machine according to the present invention will be described in detail with reference to the accompanying drawings.

First, referring to FIG. 1, the joint structure of a construction machine according to the present invention includes a first member 10 having a pin hole 12 and a second member 20 having a pin hole 22. do. The pinhole 12 of the first member 10 and the pinhole 22 of the second member 20 are aligned with each other. Here, the first member 10 includes a pair of support plates 10a, and the second member 20 is disposed between the pair of support plates 10a. Of course, pinholes 12 are formed in the pair of support plates 10a, respectively.

The joint connection structure of the present invention includes a pin 30 fitted into the pin hole 12 of the first member 10 and the pin hole 22 of the second member 20 aligned with each other. The pin 30 is configured in a hollow pipe shape having an inner diameter 32, and the hollow inner diameter 32 is configured so that lubricant oil can be stored. The hollow inner diameter 32 is a lubricant reservoir for storing lubricant.

Here, the pin 30 is composed of any one of carbon steel and alloy steel. And the inner diameter 32 diameter d of the pin 30 is 60% or less of the outer diameter 34 diameter (D). And both ends of the pin (30) is fixedly supported on both support plates (10a) of the first member (10) by a fixing bracket (36). In addition, both open sides of the inner diameter 32 are sealed by the cap 38, and at this time, as shown in FIG. 2, any one of the caps 38 on both sides may inject a lubricating oil into the inner diameter 32. 38a is formed. The injection hole 38a is closed by the plug 39. As shown in FIG. 3, a vent hole 38b is formed at the other one of the caps 38 on both sides so that the air filled in the inner diameter 32 may escape when the lubricant is injected.

On the other hand, the pin 30 of such a configuration is subjected to repeated loads and impact loads during operation, and friction contact with the pinhole 22 of the second member 20, the strength should be high and excellent wear resistance. In particular, since the hollow inner diameter 32 is formed, the fatigue strength may be lowered due to the reduction in the cross-sectional area, and thus the strength should be high. Therefore, the fin 30 of this invention is comprised so that the inner diameter 32 and the outer diameter 34 may surface-treat, and surface hardness is high.

The surface hardness of the outer diameter 34 of the fin 30 is configured to maintain a range of about HRC 50 ~ 65. This is because the surface crack may be caused by the bending load when the surface hardness is HRC 50 or less, and when the surface hardness is HRC 65 or more, cracks are generated at the paper feed hole 72 to be described later during the action of the impact load. ) Can be lost. In addition, in order to reduce the amount of wear during friction between the pin hole 22 and the bush 40 to be described later, the surface hardness of the pin should be HRC 50 or more.

And the surface hardness of the inner diameter 32 of the fin 30 has a range of about HRC 35 ~ 60. This is because when the surface hardness is HRC 35 or less, cracks may be generated at the inner diameter 32 due to the tensile stress of the inner diameter 32 when a load is applied to the pin 30. On the other hand, it is preferable that the surface hardness of the inner diameter 32 is smaller than HRC 65 which is the surface hardness of the outer diameter 34. This is to increase the resistance to impact. Most preferably, the surface hardness of the inner diameter 32 is HRC 60 or less.

In addition, since the pin 30 of such a configuration is in frictional contact with the bush 40 to be described later, the surface friction coefficient should be small. Therefore, the fin 30 of the present invention is formed with a coating layer 30a that can reduce the coefficient of friction in the outer diameter (34). The coating layer 30a is made of any one of nitride compounds by hard chromium plating, nickel plating, and nitriding heat treatment. Here, the hard chromium plating has a high surface hardness and is formed materially stable chromium oxide during frictional contact with the bush 40, so there is little wear due to sintering. In addition, the nitride compound reduces frictional resistance during frictional contact with the bush 40 and improves corrosion resistance, thereby suppressing the rust resistance on the surface of the fin 30.

Referring back to FIG. 1, the joint connection structure of the present invention includes a bush 40 disposed between the circumference of the pin 30 and the pin hole 22. As shown in FIGS. 2 and 3, a pair of bushes 40 are disposed on both sides of the pins 30, and the pins 30 and the pin holes 22 are prevented from directly contacting each other. The pinhole 22 is prevented from wearing out. Here, dust seals 42 are disposed at both ends of each bush 40. The dust seal 42 blocks various foreign matter from penetrating between the pin 30 and the bush 40 and between the bush 40 and the pin hole 22.

The bush 40 is made of a material having a lower elastic modulus and hardness than the pin 40, as an embodiment, the brass machined in the form of a bush or copper-based sintered body in which any one of graphite, molybdenum disulfide is added to It consists of. In addition, the bush 40 may be constituted by an iron-based sintered bearing containing high viscosity oil.

In addition, the joint connection structure of the present invention includes spacers 60 disposed between the support plates 10a of the second member 20 and the first member 10. The spacer 60 maintains a gap between the second member 20 and the first member 10 and prevents the second member 20 and the first member 10 from directly in frictional contact.

The spacer 60 should be made of a material that can sufficiently withstand the side thrust frictional contact generated between the second member 20 and the first member 10, and the second member 20 and the first member 10. ) It should be composed of lubricating material so that it will not be easily worn during friction contact with). The spacer 60 is made of a material having a smaller coefficient of friction than the bush 40. As a material of the spacer 60 which satisfies such conditions, there are copper-based or iron-based sintered bodies containing oil, and any one of a polymer, uranium, rubber, and heat-treated steel disk. Any one of these may be selected and used.

On the other hand, it is also possible to maintain the gap between the second member 20 and the first member 10 by using a shim instead of the spacer 60 and to adjust the gap at the same time.

Referring back to FIG. 1, the joint connection structure of the present invention includes a lubricant stored in the inner diameter 32 of the pin 30 between the pin 30 and the bush 40, and the bush 40 and the second member. Lubricating oil feeding means 70 for feeding between pinholes 22 of 20 is provided.

As shown in FIGS. 2 and 3, the lubricant feeding means 70 includes a lubricant feeding hole 72 formed in the pin 30 so as to communicate with the inner diameter 32 and a bush communicating with the lubricant feeding hole 72. The communication passage 74 formed in the 40 and the lubricating oil introduced into the communication passage 74 are interposed between the pin 30 and the bush 40 and between the bush 40 and the second member 20. It is composed of a lubricating oil feeding groove 76 formed around the inner diameter (40a) and the outer diameter (40b) of the bush 40 to be fed. Here, a plurality of lubricating oil feeding holes 72 are formed radially along the circumferential direction of the pin 30.

The lubricating oil supply means 70 of this configuration feeds the lubricating oil stored in the lubricating oil reservoir of the inner diameter 32 between the bushes 40 and between the bushes 40 and the pinholes 22 of the second member 20. Minimizes the frictional resistance generated between the bush 40 and the pin 30 and between the bush 40 and the second member 20, and thus the bush 40 and the pin 30 and the second member 20. To prevent the pin hole 22 from being worn.

On the other hand, the lubricating oil feeding hole 72 of the lubricating oil feeding means 70 should be smaller than the width of the lubricating oil feeding groove 76 of the bush 40, and its shape is advantageously elliptical than the circular in order to alleviate stress concentration. That is, when the frictional contact between the bush 40 and the pin 30 does not directly contact the lubricant supply hole 72 and the bush 40, the lubricant supply hole (not the width of the lubricant supply groove 76 of the bush 40) ( 72) should have a small outer diameter.

The present inventors have tested as shown in Table 1 and Table 2 to test the wear performance and durability of the joint structure according to the present invention.

Table 1 shows the results of the rig test according to the material of the bush 40 and the shape of the pin 30, the load is 80Mpa after the one-time lubricating oil when the bush 40 and the pin 30 is assembled, When the linear velocity of the bush 40 and the pin 30 is 1.0 m / min and the pin 30 oscillates within a range of 100 ^o (± 50), the friction between the bush 40 and the pin 30 is reduced. This test result is to set the time that the friction coefficient by

bush pin Test time (hr) material Surface treatment shape Heat treatment Surface treatment Low carbon alloy steel Carburizing pin High frequency Hard chrome plating 10 Hollow Pin High frequency Hard chrome plating 35 6.4 Brass - pin High frequency - 48 Hollow Pin High frequency - 150 Iron-copper sintering - pin High frequency - 233 Hollow Pin High frequency - 651

Table 1. Different rig test results for the combination of bush and pin

According to the test results of Table 1, when the bush material was carburized with low lubricity low carbon alloy steel, the coefficient of friction reached 0.3 in 10 hours. However, when about 200g of lubricating oil was filled in the hollow pin, the coefficient of friction reached 0.3 in 35 hours, which is about three times, which lowers the coefficient of friction between the bush and the pin.

In addition, when the 6.4 brass bush, which has better friction characteristics with the counterpart pin than the carburized low carbon alloy steel, was applied, the friction coefficient was stabilized and reached the coefficient of friction 0.3 in 48 hours. However, the wear of the bush increased about twice as much as the low alloy carburized. In the case of 6.4 brass, which was filled with 200 g of lubricating oil in the inner diameter of the pin, the time to reach the coefficient of friction 0.3 was increased three times to 150 hours.

In the case of iron-copper sintered bushes with internal pores, the time of reaching the coefficient of friction 0.3 of 6.4 brass or carburized low-carbon alloys is 233 hours, compared to 6.4 brass with hollow fins. It appeared to be longer. In the case where 200 g of lubricating oil was filled in the hollow, the test was carried out in an unloaded state for reaching a friction coefficient of 0.3 in about 650 hours and about 60 times longer than that of the carburized low-alloy carbon steel.

As a result, the joint connection structure using the sintered bush and the hollow pin can be operated without paper for the longest time.

On the other hand, Table 2 is a test result of the wear resistance characteristics of each spacer against the thrust load, the test conditions, the test speed is 1m / min, the test load is 700kg, lubricating oil in the ball on disk tester Paper feeding is a result of measuring the amount of wear after testing by applying it to the plate disk once before the test until the coefficient of friction reaches 0.3.

division 2nd member, boss material (ball shape) Spacer or Shim (Plate Specimen) Ball wear (g) Plate Wear Amount (g) Combination 1 Low carbon steel Cold rolled steel sheet 16.4 32.6 Combination 2 Low carbon steel Polymer 8.5 14.2 Combination 3 Low carbon steel Plate Bearing 8.5 10.2

Table 2. Wear Resistance Characteristics of Spacers or Shims for Thrust Loads

According to the test results of Table 2, the most suitable material combinations for the thrust loads were low carbon steels, sheet bearings, and polymers, which had better wear than the existing low carbon steels and cold rolled plates. It is believed that carbon steel and polymer materials with lower friction coefficients than steel and steel exhibit excellent friction characteristics in the material. In addition, the material combination of the plate bearing and the low carbon steel, which are oilless bearings, showed excellent friction characteristics. Here, the plate bearing refers to a plate bearing manufactured by injecting graphite into the brass and made of an oilless bearing containing oil and a sintered bearing.

In conclusion, as a spacer or shim material, copper-based or iron-based sintered bodies and polymers containing oil were found to be excellent.

Although the preferred embodiments of the present invention have been described above by way of example, the scope of the present invention is not limited to these specific embodiments, and may be appropriately changed within the scope of the claims.

As described above, in the joint structure of the construction machine according to the present invention, after the pin is hollowed and the lubricant is filled into the hollowed pin, the filled lubricant is interposed between the pin hole and the pin and the bush. By being fed, the frictional contact between the pin and the pinhole can be reduced without additional feeding for a long time. In addition, it is possible to reduce the weight by hollowing the pin to reduce the weight, thus improving the dynamic stability and durability.

Claims (10)

A first member 10 having a pair of support plates 10a having pin holes 12 formed therebetween, a second member 20 disposed between the support plates 10a and having a pin hole 22; A pin 30 fitted into the pin hole 12 of the support plate 10a and the pin hole 22 of the second member 20 aligned with each other, and both ends of which are fixed to the support plate 10a; In the joint structure of the construction machine having a bush 40 disposed between the circumference of the pin 30 and the pin hole 22 of the second member 20, The pin 30 is a hollow body having an inner diameter 32 that is open on both sides so as to store lubricating oil, and both the openings of the inner diameter 32 are closed by a cap 38, and both caps ( In one of the 38), an injection hole 38a for injecting lubricating oil into the inner diameter 32 is formed, and the other is formed with a vent hole 38b through which air of the inner diameter 32 can escape. Lubricating oil supply means for supplying the lubricant stored in the inner diameter 32 between the pin 30 and the bush 40, and between the pin hole 22 of the bush 40 and the second member 20 ( 70), The lubricating oil feeding means 70 includes a plurality of lubricating oil feeding holes 72 radially formed in the pins 30 so as to communicate with the inner diameter 32 and the bushes so as to communicate with the lubricating oil feeding holes 72. The communication passage 74 formed in the 40 and the lubricating oil introduced into the communication passage 74 are interposed between the pin 30 and the bush 40, and the bush 40 and the second member 20. Joint structure of the construction machine, characterized in that consisting of a lubricant feed groove (76) formed around the inner diameter (40a) and the outer diameter (40b) of the bush (40) to feed between. The method of claim 1, The pin 30 is composed of any one selected from carbon steel and alloy steel, the surface hardness of the outer diameter 34 is in the range of about HRC 50 to 65, the surface hardness of the inner diameter 32 is in the range of about HRC 35 to 60 Joint structure of the construction machine, characterized in that. The method according to claim 1 or 2, The outer diameter 34 of the fin 30 is formed with a coating layer 30a that can reduce the coefficient of friction, the coating layer 30a is made of any one of the nitride compound by hard chromium plating, nickel plating, nitriding heat treatment Joint structure of the construction machine, characterized in that. delete The method of claim 1, Dust seals 42 are disposed at both ends of the bush 40, so that foreign matters are between the pin 30 and the bush 40, and between the bush 40 and the second member 20. Joint structure of construction machinery to prevent penetration. The method according to claim 1 or 2, Diameter (d) of the inner diameter (32) of the pin (30) is a joint structure of the construction machine, characterized in that consisting of less than 60% of the diameter (D) of the outer diameter (34). The method according to claim 1 or 5, The bush 40 is a joint structure of the construction machine, characterized in that composed of any one of a sintered body in which any one of graphite, molybdenum disulfide is added to the brass. The method according to claim 1 or 5, The bush 40, the joint structure of the construction machine, characterized in that consisting of a sintered bearing containing high viscosity oil. The method according to claim 1 or 5, The bush 40 is a joint structure of the construction machine, characterized in that consisting of brass. The method of claim 1, Further comprising spacers 60 disposed between the second member 20 and each of the support plates 10a of the first member 10, The spacer 60 is a joint structure of the construction machine, characterized in that consisting of any one of copper-containing sintered body, oil-containing iron-based sintered body, polymer, heat-treated steel sheet.

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