JP4509762B2 - Sliding member - Google Patents

Description

  The present invention relates to a sliding member that can suppress abrasive wear and extend the life of a component even in a use environment in which foreign particles are mixed in a contact interface.

  In excavation apparatuses such as construction machines, for example, in a hydraulic excavator, a bucket is connected to the tip of an arm. In the excavation operation by the bucket, the bucket cylinder is operated to rotate or swing the bucket around the connecting portion with the arm.

  The bearing device that constitutes the connecting portion (joint portion) between the bucket and the arm has a boss portion provided mainly on the distal end side of the arm and a pair of bracket portions provided on the proximal end side of the bucket, A boss portion is arranged between the pair of bracket portions, and these are rotatably connected using a connecting pin.

  Moreover, the opposing end surfaces of the boss portion and the bracket portion are sliding surfaces on which both slide. Then, the thrust load acting on the boss portion side or the bracket portion side is received by the sliding surface (thrust surface), so that the bracket portion relative to the boss portion in the thrust direction (axial direction of the connecting pin) I try to prevent sticking.

  Lubricating oil is supplied to the sliding surface of the connecting part between the bucket and the arm from the hole provided in the bush, or the bush is made of a porous body, and the lubricating oil is confined in the hole and lubricated as the sliding starts. By causing the oil to flow from the inside of the bush to the sliding surface, the occurrence of seizure, galling, wear, etc. is suppressed, and a bearing that is slidable over a long period of time without lubrication is provided (for example, Patent Document 1, 2).

  By the way, in excavating apparatuses such as construction machines such as buckets of the above hydraulic excavator, in order to perform excavation, transfer, loading and the like of earth and sand, during the work, earth and sand are connected to the connecting portion between the bucket and the arm. Intrusive foreign particles such as

  Therefore, if the earth and sand enter the slight gaps between the thrust surfaces of the bush and the shaft part receiving the thrust load and the bracket part and the shaft part (contact interface of the sliding part), the earth and sand will slide on the thrust surface during sliding. Scratches and the like are formed, causing abrasive wear, resulting in a problem that the wear of the thrust bearing portion is accelerated. For this reason, it takes time to replace and repair the sliding parts.

  Although intrusion of earth and sand can be suppressed at the contact interface of the sliding portion, it is substantially difficult to eliminate the invasion of earth and sand. Therefore, it is necessary to take measures against the abrasive wear on the premise that the earth and sand enter the contact interface of the sliding portion. As a method for solving this problem, it has been conventionally proposed to solve the problem by improving the wear resistance of the thrust surface that receives the thrust load.

As this method, for example, it has been proposed to use a ceramic material such as tungsten carbide (WC) or a super hard material on the thrust surface or to thermally spray the material to suppress the wear ( (See Patent Document 3). In addition, a sliding part structure has also been proposed in which an adherend having excellent sliding characteristics and wear resistance is surface-bonded onto an strength member with an adhesive (see Patent Document 4).
JP-A-10-82423 (Claim, FIG. 1) JP 2004-100812 A (claim, FIG. 1) JP-A-9-184518 (Claim, FIG. 1) JP 2004-60814 A (claim, FIG. 1)

  However, even when the contact interface of the sliding portion is coated or bonded with a material having excellent sliding characteristics and wear resistance, abrasive wear due to intrusion soil is inevitable. In addition, when the material having excellent sliding characteristics and wear resistance is entirely covered on the contact interface of the sliding portion, it tends to be seized on the high surface pressure side. For this reason, a new problem arises, such as it being impossible to apply a high load or use in a non-greased state for a long time (about 500 hours or more). Further, it is complicated to cover or bond the material having excellent sliding characteristics and wear resistance over the entire surface.

  For this reason, it is possible to prevent abrasive wear on the premise of the intrusion of the above earth and sand without covering or adhering the material with excellent sliding characteristics and wear resistance to the contact interface of the sliding part entirely. Therefore, there is a demand for a sliding member or a bearing that can slide over a long period of time without lubrication.

  In general, when dust or oil often accumulates on the contact interface of the sliding member, a groove is provided on the sliding surface, or graphite is used as a lubricant supply source in various places on the sliding surface. The sliding characteristics are improved by arranging them to function as a solid lubricant. However, even with this method, there is a great limit to the improvement of the sliding characteristics of a sliding member in which abrasive wear due to intruding earth and sand occurs.

  Accordingly, an object of the present invention relates to a sliding member capable of suppressing the abrasive wear and extending the life of a component even under a use environment in which foreign particles are mixed in a contact interface.

To this end, the sliding member of the present invention, in the sliding member surface of the shaft side is in sliding contact with the inner circumferential surface of the bearing side, the inner peripheral surface of the bearing side, of the shaft side surface and Rutotomoni lubricant porous spots supplies are provided in the contact interface of the inner peripheral surface of the bearing side, over the inner circumferential surface of the bearing side, accommodating foreign particles mixed in the contact interface Concave pockets arranged alternately with the porous material spots , and the concave pockets are spaced apart from each other in the axial direction of the bearing so as to be parallel to each other in the circumferential direction. It is a concave groove structure provided, or a circular hole structure provided linearly and parallel to each other in a direction inclined with respect to the axial direction of the bearing. is there.

In the present invention, first, the inner peripheral surface of the bearing side, a porous body spots supplying lubricant is provided at the contact interface of the inner peripheral surface of the shaft-side surface and the bearing side, slidable over a long period of time in oilless And

In addition, over the inner peripheral surface of the bearing side, concave pockets containing foreign particles mixed in the contact interface are arranged and provided alternately with the porous body spots , and The concave pocket has a concave groove structure provided so as to be spaced apart from each other in the axial direction of the bearing and parallel to each other in the circumferential direction, or inclined with respect to the axial direction of the bearing The circular hole structure is linear and parallel to each other in the direction, so that even under the usage environment where foreign particles enter or enter the contact interface, it suppresses abrasive wear and extends the life of the parts. Extend.

  Embodiments of the present invention will be described below in detail with reference to the drawings. First, a typical bearing device configuration that constitutes a connecting portion (joint portion) between a bucket and an arm of a hydraulic excavator, which is a premise of the sliding member of the present invention, will be described with reference to FIG. FIG. 1 is a longitudinal sectional view of the bearing device.

  In the bearing device of FIG. 1, a bush 21 is fitted inside the boss 20. A seal 27 is pressed into the outer periphery of the side portion of the bush 21. Brackets 22 are provided on both sides of the boss 20, and shims 23 are interposed in the gap between the boss 20 and the bracket 22. An O-ring 24 is attached outside the upper end of the gap. A shaft 25 is inserted through the bracket 22 and the bush 21 at both ends. The shaft 25 is made non-rotatable by a rotation locking bolt 26 penetrating the shaft 25 and the bracket 22.

  In the bearing device of FIG. 1, the bush 21 is a fixed side, the shaft 25 is a movable side, and the surface (sliding portion) 25a on the shaft 25 side is slidably contacted with the surface (sliding portion) 21a on the other bush 21 side. Thus, a sliding member is configured. The sliding member of the present invention has various shapes and structures depending on the application, and the base material is also a metal material such as steel, iron, aluminum alloy, copper, alumina, zirconia, etc., depending on the application. A ceramic material is appropriately selected.

  In the bearing device structure of FIG. 1 as described above, the porous body spots 1 for supplying the lubricant are arranged on the surface (sliding portion) 21a on the bush 21 side. Moreover, the concave pocket 2 which accommodates the foreign particle mixed in the contact interface is arranged in the surface (sliding part) 21a on the same bush 21 side. In the embodiment of FIG. 1, the porous spots 1 and the concave pockets 2 are alternately arranged on the peripheral surface on the bush 21 side and in the circumferential direction at regular intervals.

(Porous spot)
First, specific embodiments of the porous spot 1 will be described below with reference to FIGS.
2 (a), 2 (b), and 2 (c) show perspective views of the porous body spot provided on the surface (sliding portion) 21a on the bush 21 side. Basically, these porous body spots are obtained by providing a porous porous body 1 that can be impregnated with a lubricant on the surface 21a of the bush 21 in the form of strips or strips.

  The porous body of FIG. 2 (a) is spaced from the surface (inner peripheral surface) 21a of the bush 21 along the circumferential direction, and is parallel to the axial direction of the bush 21. A typical band 1a is provided.

  The porous body shown in FIG. 2B is provided with a plurality of porous bands 1b spirally formed on the surface (inner peripheral surface) 21a of the bush 21 in the axial direction of the bush 21. is there.

  The porous body of FIG. 2 (c) is a combination of the porous band 1a of FIG. 2 (a) and the porous band 1b of FIG. 2 (b).

  The band or strip of the porous body 1 may be directly sprayed or bonded to the surface (inner peripheral surface) 21a of the bush 21. However, from the viewpoint of increasing the adhesive strength and the amount of the lubricant impregnated, a concave groove corresponding to the band or strip of the porous body 1 to be provided is provided on the surface (inner peripheral surface) 21a of the bush 21, and the concave groove is provided within Alternatively, thermal spraying or bonding may be performed so as to accommodate the band or strip of the porous body 1.

  The porous body 1 may be a porous sintered alloy using metal powder such as copper powder or iron powder alone or in combination, but in general, wood ceramics (CRB ceramics) or rice bran It is preferable to use porous particles made of a carbon material made of a plant made of a porous carbon material of a plant such as wood, bamboo, rice husk, rice bran, etc., called ceramics (RB ceramics).

  Among these, rice bran ceramic is a porous material having a hardness of 25 to 100 times that of graphite and a strength of 14 to 50 times, and a porosity of 40 to 50%. The coefficient of friction μ in the non-lubricated state is about 0.13 to 0.2, has wear resistance 1,000 times or more that of steel, and has excellent corrosion resistance. For this reason, it is used as a constituent material for bearings, bushes, and sliding members themselves.

  This rice bran ceramic is a powdery porous carbon produced by mixing a phenolic resin with a plant raw material such as defatted rice bran as a raw material and drying it, followed by carbonization firing at 300 to 1100 degrees in a nitrogen gas atmosphere. Obtained as a material.

  The structure of these rice bran ceramics or wood ceramics is made of amorphous carbon inside and has a lot of pores, and the surroundings are glassy carbon. For this reason, as compared with porous sintered alloys and the like, as described above, both the specific wear amount and the friction coefficient are extremely small and have excellent friction characteristics and slidability. It also has excellent oil retention and oil release properties.

  For these porous bodies, the size, shape, number of arrangements, arrangement positions, etc. of the porous bodies are appropriately selected according to the required lubrication amount of the contact interface in the sliding member. However, it is not necessary to cover the entire sliding surface like the above-mentioned wear resistant material.

(Foreign particle storage pocket)
FIGS. 3A, 3B, and 3C are perspective views each showing an aspect in which concave pockets for accommodating foreign particles mixed in the contact interface are arranged over the surface (sliding portion) 21a of the bush 21. FIG. Show. These pockets are basically provided on the surface of the bush 21 with a concave groove (concave groove) having a cross section and a cross sectional shape that can accommodate foreign particles mixed in the contact interface.

  The concave pockets in FIG. 3 (a) are spaced apart from each other along the circumferential direction of the surface (inner circumferential surface) 21a of the bush 21, and are parallel to the axial direction of the bush 21. Is provided.

  The concave pockets in FIG. 3 (b) are arranged on the surface (inner peripheral surface) 21 a of the bush 21 in a spiral or parallel to the axial direction of the bush 21 and spaced from each other in the axial direction of the bush 21. Thus, a large number of concave grooves 2a are provided.

  The concave pocket in FIG. 3 (c) is provided with a large number of holes, dents, and indentations 3 that are not penetrated on the surface (inner peripheral surface) 21a of the bush 21 with appropriate intervals.

  These concave pockets can be provided by machining the surface (inner peripheral surface) 21 a of the bush 21. These concave pockets are appropriately selected in terms of size, cross-sectional shape, number of arrangement, arrangement position, etc. that can accommodate foreign particles according to the size and shape of foreign particles such as earth and sand that are likely to be mixed into the contact interface, or the amount of contamination. .

  In the embodiment described above, the porous body may have a shape as shown in FIGS. 3A, 3B, and 3C, and conversely, the concave pocket for accommodating the foreign particles is formed as shown in FIG. It is good also as a shape like (b) and (c).

(Combination of porous material spot and concave pocket)
2 (a), (b) and (c) are provided in combination with the porous spot 1 shown in FIGS. 2 (a), (b) and (c) and a concave pocket for accommodating foreign particles. Examples are shown in FIGS. Each of FIGS. 4 to 6 (a) and FIG. 7 shows the bush 21 in a plan view, and each of FIGS. 4 to 6 (b) shows a cross-sectional view of each (a) of FIGS.

  In the present invention, the embodiment is not necessarily limited to the cylindrical bush 21 and can be applied to a sliding member having a flat sliding surface. Therefore, the modes of FIGS. An aspect of a sliding member having a flat moving surface is also shown.

  FIG. 4 shows an example in which the surface 21a of the bush 21 is provided with a linear porous band 1a and a linear groove 2a which are parallel to each other and alternately in the axial direction of the bush 21, for example. is there. The direction of provision may be the width direction of the bush 21. In this case, as described above, the band 1a of the porous body is respectively accommodated in the concave groove 4 provided on the surface of the bush 21.

  In FIG. 5, the surface 21 a of the bush 21 is provided with a linear porous band 1 b and a linear groove 2 a that are inclined with respect to the bush 21 in parallel and alternately. Is. This corresponds to the spiral arrangement of FIG. Also in this case, the band 1b of the porous body is accommodated in the concave groove 4 provided on the surface 21a of the bush 21, respectively.

  6, the surface 21 a of the bush 21 is provided with the bands 1 c and 1 d of the porous body of FIG. 2C and the linear concave groove 2 a that are inclined with respect to the bush 21. Is. Also in this case, the bands 1 c and 1 d of the porous body are respectively accommodated in the concave grooves 4 provided on the surface 21 a of the bush 21.

  In FIG. 7, it is assumed that the porous body 1e is embedded in the circular hole 3 as shown in FIG. 2 (c), and the concave grooves are also formed as the circular holes 3, and are inclined linearly and in parallel with each other. This is provided on the surface 21 a of the bush 21. The arrangement direction of the circular holes 3 is arbitrary.

  As described above, the mode in which the means 1 for supplying the lubricant is provided on the bushing-side surface 21a of the sliding member and the concave pockets 2 for containing the mixed foreign particles are arranged. This is because, in the case of a bush or a bearing, the bush side or the bearing side is easier to provide than the shaft side, the surface area is large, and it is efficient in terms of effect. However, in the case of the planar sliding member shown in FIGS. 4 to 7, there is no difference in efficiency as in the bush and the bearing, regardless of which sliding portion is provided. Accordingly, whether or not the means 1 for supplying the lubricant and the recessed pocket 2 are provided on either one or both sides of the sliding member is appropriately selected for each application.

(Porosity spot and concave pocket action)
The action of the porous body spot and the concave pocket described above will be described with reference to FIG. FIG. 8 corresponds to the cross-sectional view of each (b) of FIGS. In FIG. 8, 5a is foreign particle | grains, such as earth and sand which penetrate | invaded the contact interface 6 of the sliding member. The contact interface 6 of the sliding portion corresponds to, for example, the contact interface between the shaft 25 and the bush 21 in the hydraulic excavator shown in FIG.

  Normally, foreign particles 5a such as earth and sand which have entered the contact interface 6 of the sliding member cause abrasive wear on the surface 25a of the shaft 25 and the surface 21a of the bush 21 which are thrust surfaces. On the other hand, in the present invention, since the concave pockets 2a are arranged over the surface 21a of the bush 21, the foreign particles 5a are conveyed by the lubricant 7 at the contact interface 6, and are formed as concave pockets 5b. It is quickly accommodated in 2a. For this reason, even under the use environment where the foreign particles 5a are mixed in or enter the contact interface 6, the abrasive wear can be suppressed and the life of the parts can be extended.

  And in this invention, lubricants, such as lubricating oil, slide from the band 1a of the porous body accommodated in the concave groove 4 provided many over the surface 21a of the bush 21 which is a sliding part surface. Sequentially and continuously supplied to the contact interface 6 of the member. For this reason, it can be slidable over a long period of time without lubrication.

  According to the present invention, it is possible to provide a sliding member capable of suppressing the abrasive wear and extending the life of the component even under a use environment where foreign particles are mixed in the contact interface. Therefore, the present invention can be applied to a sliding member such as a shaft and a guide surface in a machine in a usage environment in which foreign particles are mixed in the contact interface other than the connecting portion between the bucket and the arm in the hydraulic excavator.

It is a longitudinal cross-sectional view which shows the one aspect | mode of this invention sliding member. It is a perspective view which shows the various aspects of the porous body spot in this invention. It is a perspective view which shows the concave pocket various aspects in this invention. FIG. 4A is a plan view and FIG. 4B is a longitudinal sectional view showing an embodiment of the sliding member of the present invention. FIG. 4 (a) is a plan view and FIG. 4 (b) is a longitudinal sectional view showing another embodiment of the sliding member of the present invention. FIG. 4 (a) is a plan view and FIG. 4 (b) is a longitudinal sectional view showing another embodiment of the sliding member of the present invention. It is a top view which shows another aspect of this invention sliding member. It is sectional drawing which shows the effect | action of this invention sliding member.

Explanation of symbols

1: porous spot, 2: concave pocket, 3: hole, 4: concave groove,
5: foreign particles, 6: contact interface, 7: lubricating oil,
20: Boss, 21: Bush, 22: Bracket, 23: Shim, 24: O-ring, 25: Shaft, 26: Rotating locking bolt, 27: Seal,

Claims (4)

In the sliding member in which the surface of the shaft side is in sliding contact with the inner circumferential surface of the bearing side, the inner peripheral surface of the bearing side, the lubricant on the contact surface of the inner peripheral surface of the bearing side and the shaft-side surface Rutotomoni provided porous spot supply, the over the inner peripheral surface of the bearing side, arranged so recessed pocket to accommodate foreign particles mixed in the contact interface becomes alternately with the porous body spots And the concave pockets are concave groove structures provided so as to be spaced apart from each other in the axial direction of the bearing and parallel to each other in the circumferential direction, or the shaft of the bearing A sliding member characterized by a circular hole structure provided linearly and parallel to each other in a direction inclined with respect to the direction . The sliding member according to claim 1, wherein the bearing is constituted by a boss and a bush fitted inside the boss . The sliding member according to claim 1 or 2 , wherein the porous spot is made of wood ceramics or rice bran ceramics.   The sliding member according to claim 1, wherein the sliding member is for construction machinery.

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