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CN-121977018-A - Self-lubricating graphite bushing with non-adhesive multilayer structure and preparation method thereof

CN121977018ACN 121977018 ACN121977018 ACN 121977018ACN-121977018-A

Abstract

The invention relates to the technical field of machining, in particular to a glue-free multilayer self-lubricating graphite bushing and a preparation method thereof. The graphite bushing comprises an outer sleeve, a middle sleeve and an inner sleeve which are sequentially sleeved and fixedly connected from outside to inside, wherein a plurality of graphite mounting holes penetrating through the wall thickness of the middle sleeve are formed in the wall of the middle sleeve, graphite columns are embedded in the graphite mounting holes in a tight fit mode, the inner sleeve is formed on the inner wall of the middle sleeve and wraps the inner side end parts of the graphite columns, the outer end faces of the graphite columns are flush with the outer surface of the middle sleeve, the inner end faces of the graphite columns are flush with the inner surface of the inner sleeve, and the inner sleeve and the middle sleeve, the inner sleeve and the graphite columns are fixedly connected into a whole through metallurgical bonding. The invention replaces gluing with mechanical and metallurgical bonding, eliminates glue pollution, and improves the fixing reliability, the overall structural strength and the thermal stability of the graphite column.

Inventors

  • YE GUIFENG
  • CUI YI

Assignees

  • 天津金键航天设备有限公司

Dates

Publication Date
20260505
Application Date
20260130

Claims (10)

  1. 1. The non-adhesive multilayer self-lubricating graphite bushing is characterized by comprising an outer sleeve, a middle sleeve and an inner sleeve which are sleeved and fixedly connected in sequence from outside to inside; the wall of the middle sleeve is provided with a plurality of graphite mounting holes penetrating through the wall thickness of the middle sleeve, and graphite columns are embedded in the graphite mounting holes in a tight fit mode; The inner sleeve is formed on the inner wall of the middle sleeve and wraps the inner side end part of the graphite column, the outer end surface of the graphite column is flush with the outer surface of the middle sleeve, the inner end surface of the graphite column is flush with the inner surface of the inner sleeve, and the inner sleeve and the middle sleeve, the inner sleeve and the graphite column and the middle sleeve and the outer sleeve are fixedly connected into a whole through metallurgical bonding. .
  2. 2. The adhesive-free, multi-layer, self-lubricating graphite liner of claim 1, wherein the outer sleeve and the intermediate sleeve are both made of steel and the inner sleeve is made of a copper alloy.
  3. 3. The gum-free multi-layer self-lubricating graphite bushing of claim 2, wherein said inner sleeve is an integral copper layer formed by a centrifugal casting or sintering process.
  4. 4. A glue-free multi-layer self-lubricating graphite bushing as claimed in claim 3, wherein there is a micro gap or a predetermined void passage for molten copper to pass through between the inner wall of the graphite mounting hole and the outer wall of the graphite column.
  5. 5. The adhesive-free, multi-layer, self-lubricating graphite liner of claim 4, wherein the intermediate sleeve is formed by crimping a plate-like substrate material with an axial seam extending through the wall of the intermediate sleeve.
  6. 6. The gum-free multi-layer self-lubricating graphite bushing of claim 5, wherein said outer jacket and said intermediate jacket are in a clearance fit, and wherein a portion of the copper alloy melts and infiltrates into the clearance during centrifugal casting and cools to form a copper support connecting said outer jacket and said intermediate jacket.
  7. 7. The gum-free multi-layer self-lubricating graphite bushing of claim 1, wherein the end surface area of said graphite posts on the inside of said inner sleeve is smaller than the end surface area of said posts on the outside of said intermediate sleeve.
  8. 8. The glue-free multilayer self-lubricating graphite bushing as claimed in claim 1, wherein inner walls of the upper and lower ends of the inner sleeve are provided with positioning convex rings, and sealing rings are assembled on the positioning convex rings; the sealing ring comprises a main sealing body pressed at the bottom of the positioning convex ring and a sealing lip integrally formed with the main sealing body, and/or comprises a rigid framework and a rubber sealing body wrapped outside the rigid framework.
  9. 9. The glue-free multilayer self-lubricating graphite bushing as claimed in claim 8, wherein the positioning convex ring is provided with a notch, one side of the notch is provided with a sloping platform which inclines towards the inner side of the bushing, the bottom of the other side of the notch is provided with a groove, the sealing ring is annular with a truncated surface, the truncated surfaces of the two ends of the sealing ring are aligned, and at least one of the truncated ends of the sealing ring is provided with an axial through hole.
  10. 10. The method for preparing the glue-free multilayer self-lubricating graphite lining according to any one of claims 1 to 9, further comprising the following steps: S1, processing a jacket; S2, processing graphite mounting holes in matrix arrangement on a flat plate, and then rolling the flat plate into an intermediate sleeve with an axial seam; s3, pressing the graphite column into the graphite mounting hole of the middle sleeve in a tight fit mode; S4, putting the middle sleeve inlaid with the graphite column into the outer sleeve to form an outer sleeve-middle sleeve assembly; s5, placing copper alloy materials into the cavity of the assembly, and welding temporary sealing plates at two ends of the assembly to form a closed cavity; s6, installing the assembly on a centrifugal machine for rotation, melting the copper alloy into copper water through induction heating, uniformly paving the copper water on the inner wall of the middle sleeve under the action of centrifugal force, and enabling part of the copper water to enter a gap between the outer sleeve and the middle sleeve through a joint and a pore channel; s7, stopping heating, keeping the workpiece rotating until the copper water is completely solidified, and cutting off sealing plates at two ends after cooling; s8, radially cutting the workpiece according to a preset length to form a single body, and finishing an inner hole of the single body to enable the inner surface of the inner sleeve to be flush with the inner end surface of the graphite column.

Description

Self-lubricating graphite bushing with non-adhesive multilayer structure and preparation method thereof Technical Field The invention relates to the technical field of machining, in particular to a glue-free multilayer self-lubricating graphite bushing and a preparation method thereof. Background Conventional self-lubricating copper steel graphite bushings typically employ a structure in which a copper sleeve with a graphite post embedded therein is side-pressed within the steel sleeve. The copper sleeve is pre-processed with a mounting hole, and graphite lubrication particles are adhered and fixed in the hole through glue. In the actual service process, because the graphite material is softer than copper, graphite particles gradually wear and fall off to form graphite powder when the graphite powder is rubbed with a shaft, so that a solid lubrication effect is achieved. However, this conventional structure has the following significant drawbacks: 1) The used fixed glue is not a lubricating medium, the viscosity of the fixed glue can cause the falling metal powder scraps, graphite powder and the like to be mutually bonded to form a hard particle mixture with grindability, so that the fixed glue cannot assist in lubrication, and the abnormal abrasion of a shaft and a sleeve can be aggravated; 2) The adhesive strength of the glue is greatly affected by temperature, and is easy to soften or lose efficacy under the working condition of one hundred degrees generated by friction, so that graphite particles fall off integrally, and the fallen glue residues are mixed with a lubricating medium to form uncontrollable viscous colloid, so that the lubricating state is further destroyed. 3) The thermal expansion coefficient difference between the traditional single-layer copper sleeve or steel sleeve and the matrix outer sleeve is large, and when friction heating occurs, the friction heating is not coordinated, so that looseness or deformation is easily caused between the lining and the outer sleeve, and the matching precision and the bearing capacity are affected. Therefore, a self-lubricating bushing and a high-efficiency preparation method are needed, which can eliminate glue fixation, improve the bonding reliability of graphite particles, improve the lubrication purity and have better structural stability. Disclosure of Invention Aiming at the defects in the prior art, the invention discloses a glue-free multilayer self-lubricating graphite bushing and a preparation method thereof, which are used for solving the problems of lubrication pollution, easy graphite falling and poor structural thermal stability caused by the fact that the self-lubricating bushing is fixed with graphite by using glue in the prior art. In order to achieve the technical aim, on the one hand, the invention provides a glue-free multilayer self-lubricating graphite bushing, which comprises an outer sleeve, a middle sleeve and an inner sleeve, wherein the outer sleeve, the middle sleeve and the inner sleeve are sleeved and fixedly connected in sequence from outside to inside; the wall of the middle sleeve is provided with a plurality of graphite mounting holes penetrating through the wall thickness of the middle sleeve, and graphite columns are embedded in the graphite mounting holes in a tight fit mode; The inner sleeve is formed on the inner wall of the middle sleeve and wraps the inner side end part of the graphite column, the outer end surface of the graphite column is flush with the outer surface of the middle sleeve, the inner end surface of the graphite column is flush with the inner surface of the inner sleeve, and the inner sleeve and the middle sleeve, the inner sleeve and the graphite column and the middle sleeve and the outer sleeve are fixedly connected into a whole through metallurgical bonding. As a preferable technical scheme, the outer sleeve and the middle sleeve are both made of steel materials, and the inner sleeve is made of copper alloy. As a preferable technical scheme, the inner sleeve is an integrated copper layer formed by a centrifugal casting process. As a preferable technical scheme, a micro gap or a preset pore channel for molten copper to pass through is formed between the inner wall of the graphite mounting hole and the outer wall of the graphite column. As a preferred technical scheme, the middle sleeve is formed by curling a platy base material, and the wall of the middle sleeve is penetrated with an axial seam. As a preferable technical scheme, the outer sleeve and the middle sleeve are in clearance fit, part of copper alloy is melted and permeated into the clearance during centrifugal casting, and a copper support body for connecting the outer sleeve and the middle sleeve is formed after cooling. As the preferable technical scheme, the inner wall of the graphite mounting hole is a rough wall surface so as to increase the friction resistance between the inner wall and the outer wall of the graphite column and p