CN215292703U

CN215292703U - Wear-resistant structure for aluminum-based piston skirt and aluminum-based piston

Info

Publication number: CN215292703U
Application number: CN202121665314.5U
Authority: CN
Inventors: 王浩伟; 汪明亮; 陈东; 夏存娟; 吴一; 王鹏举
Original assignee: Anhui Xiangbang Composite Material Ltd; Shanghai Jiaotong University
Current assignee: Anhui Xiangbang Composite Material Ltd; Shanghai Jiaotong University
Priority date: 2021-07-21
Filing date: 2021-07-21
Publication date: 2021-12-24
Anticipated expiration: 2031-07-21

Abstract

The utility model provides a wear-resisting structure and aluminium base piston for aluminium base piston skirt portion. The wear-resisting structure includes that a plurality of is according to the star arch of square matrix arrangement, and the protruding star of star is: the four first arc line segments and the four second arc line segments are alternately connected to form a graph, each first arc line segment is concave, and each second arc line segment is convex. The utility model provides a novel collection oil cloth oily structure to its surface increases the wearing layer, can show lubricity and the life that promotes aluminium base piston.

Description

Wear-resistant structure for aluminum-based piston skirt and aluminum-based piston

Technical Field

The utility model relates to a piston of internal-combustion engine especially relates to a wear-resisting structure for aluminium base piston skirt portion to and have above-mentioned wear-resisting structure's aluminium base piston, belong to engine technical field.

Background

An aluminum-based piston generally refers to an aluminum alloy piston or an aluminum-based composite piston, and such a piston is one of the key components of an engine, and a piston skirt plays roles of guiding, bearing side pressure, heat transfer and the like in a cylinder. During the working process of the aluminum-based piston, due to the second-order motion of the piston, the skirt part of the piston is subjected to great side thrust and high-temperature and high-pressure heat load, the skirt part of the piston is deformed, and the phenomena of cylinder biting and cylinder pulling can occur due to the fact that a local gap between the skirt part of the piston and a cylinder sleeve is too small; or the phenomenon of cylinder knocking, increasing engine oil consumption, cylinder sleeve cavitation erosion or overlarge noise and the like can be caused due to overlarge clearance; or after the skirt is deformed, lubrication is difficult to achieve, thereby affecting operational reliability.

The reasonable profile of the skirt part of the piston ensures that the piston obtains good guide and enough bearing area to form enough lubricating oil film so as to reduce friction and abrasion and ensure reasonable clearance of the cylinder under any working condition. Therefore, improvement of the lubrication frictional wear of the skirt portion is an important issue. In order to improve the lubrication of the skirt part, an oil collecting and distributing hole can be processed on the surface of the skirt part. When the abrasion resistance of the piston is improved, surface strengthening treatment is often adopted, such as graphite spraying, molybdenum disulfide spraying, tin plating or lead plating and the like on the surface of the piston.

There is room for further improvement in these existing wear resistant constructions and materials of aluminum-based piston skirts.

SUMMERY OF THE UTILITY MODEL

The utility model aims at improving aluminium base piston skirt's collection oil cloth oily structure to how, and improve aluminium base piston skirt surface material's wear resistance's problem.

In order to solve the above technical problem, the purpose of the utility model can be realized through following scheme:

in a first aspect, the present invention provides a wear-resistant structure (piece) for an aluminum-based piston skirt, the wear-resistant structure (piece) includes a plurality of star-shaped protrusions arranged in a square matrix on the surface of the piston skirt, the star-shaped protrusions refer to: the first arc line section is concave, and the second arc line section is convex.

In some embodiments, the wear resistant structure consists of only star-shaped protrusions.

In some embodiments, the star-shaped protrusions have a height of 0.5 to 2 mm.

In some embodiments, each star projection has a spacing from an adjacent star projection.

In some embodiments, the length of the gap is less than one third of the distance between the geometric centers of two adjacent star-shaped protrusions.

In some embodiments, the top surface of the star-shaped protrusion is spherical.

In some embodiments, the edges of the top surface of the star-shaped projection are rounded.

In some embodiments, the tangent curve of the fillet is an elliptical line.

In some embodiments, the surface of the wear resistant structure is provided with a wear resistant coating.

In some embodiments, the wear resistant coating has a thickness of 10 to 500 micrometers.

In some embodiments, the wear resistant coating is a graphite layer or a molybdenum disulfide layer.

In some embodiments, the wear resistant coating is a graphite layer containing carbon fibers. And the carbon fibers are distributed on the surface of the wear-resistant coating and in the inner part close to the surface.

In a second aspect, the utility model also provides an aluminium base piston, aluminium base piston's skirt portion surface arranges above-mentioned wear-resisting structure.

The utility model discloses following beneficial effect has:

1. the novel oil collecting and distributing structure is provided, and the wear-resistant coating is added on the surface of the novel oil collecting and distributing structure, so that the lubricating property and the service life of the aluminum-based piston can be obviously improved.

2. Compared with the traditional concave structure, the shape and the function of the concave part provided by the utility model are different. The concave part is flush with the wall surface of the piston, and abrasive dust is not easy to remain; but is concave relative to the surrounding plurality of projections. The lubricating oil of the engine has a considerable viscosity, and the lubricating oil entering the concave part from the inlet and the outlet between the bulges can temporarily stay in the concave part, so that the lubricating oil is distributed on the whole wall surface of the piston during the stable work, wherein a large amount of lubricating oil is positioned in the concave part, and a small amount of lubricating oil is positioned on the top surface and the side surface of the bulge.

3. The star-shaped bulges are arranged into a square matrix, a nearly circular recess is arranged in the middle of the 4 star-shaped bulges for retaining lubricating oil, and the star-shaped bulges can not be arranged into a hexagonal matrix.

Drawings

Other features, objects and advantages of the invention will become more apparent upon reading of the detailed description of non-limiting embodiments with reference to the following drawings:

fig. 1 is a schematic top view of a wear-resistant structure according to a preferred embodiment of the present invention;

fig. 2 is a schematic perspective view of a wear-resistant structure according to a preferred embodiment of the present invention;

FIG. 3 is a schematic cross-sectional view of a wear-resistant coating in accordance with a preferred embodiment of the present invention;

wherein, 11, the first star-shaped bulge, 12, the second star-shaped bulge, 13, the third star-shaped bulge, 14, the fourth star-shaped bulge, 20 and the concave part.

Detailed Description

The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. The following examples are implemented on the premise of the technical solution of the present invention, and provide detailed embodiments and specific operation processes, which will help those skilled in the art to further understand the present invention. It should be pointed out that the scope of protection of the present invention is not limited to the following embodiments, and that a plurality of adjustments and improvements made on the premise of the concept of the present invention all belong to the scope of protection of the present invention.

Unless otherwise defined, technical or scientific terms used in the claims and the specification of this patent shall have the ordinary meaning as understood by those of ordinary skill in the art to which this patent belongs.

As used in this specification and the appended claims, the terms "first," "second," and the like do not denote any order, quantity, or importance, but rather are used to distinguish one element from another. The terms "a" or "an," and the like, do not denote a limitation of quantity, but rather denote the presence of at least one. In the description of this patent, unless otherwise indicated, "a plurality" means two or more. The word "comprising" or "having", and the like, means that the element or item appearing before "comprises" or "having" covers the element or item listed after "comprising" or "having" and its equivalent, but does not exclude other elements or items.

The surface micro-nano structure arranged according to a certain rule is obtained through active design and manufacturing, namely a pattern array with micro-nano size and arrangement is processed on the surface, so that the surface with a specific function, namely a textured surface, is obtained. The surface texture can be simply divided into two forms of concave texture and convex texture according to the position of the surface texture relative to the surface of the metal substrate.

The concave texture may form a semi-enclosed space, as compared to the convex texture, so that lubricating oil, abrasive dust, abrasive grains, etc. may be more effectively stored. However, the stored abrasive dust, particles, may be deposited inside the concave texture, thereby reducing the effect of the concave texture to some extent. For convex texture, the flow of lubricant will more easily carry away swarf and abrasive particles from the convex texture surface, thereby reducing the deposition similar to that of concave texture. The convex texture and the concave texture have the advantages and the disadvantages respectively, and the method of the utility model combines the convex texture and the concave texture, thereby developing the advantages and avoiding the disadvantages.

A preferred embodiment of the present invention will be described in detail below with reference to the accompanying drawings.

Example 1

Fig. 2 is a schematic view showing a wear-resistant structure of an aluminum-based piston skirt, and fig. 1 is a plan view thereof. The wear-resistant structure protrudes from the surface of the metal matrix of the aluminum-based piston skirt and belongs to the convex texture in principle. The wear-resistant structure is composed of a plurality of star-shaped protrusions arranged according to a square matrix. The section of the star-shaped bulge is star-shaped, and the star-shaped means that: the figure formed by connecting four first arc line segments and four second arc line segments alternately is characterized in that each first arc line segment is concave, and each second arc line segment is convex, as shown in figure 1. The square matrix is formed by intersections of a plurality of parallel and equidistant virtual transverse lines and longitudinal lines (not shown in the figure), and the geometric center of each star coincides with the intersections one by one. The wear-resistant structure may also comprise protrusions of other shapes, but preferably consists of only star-shaped protrusions.

This is so set that every four adjacent star-shaped protrusions define a recessed portion, such as the recessed portion 20 defined by the first star-shaped protrusion 11, the second star-shaped protrusion 12, the third star-shaped protrusion 13, and the fourth star-shaped protrusion 14 in fig. 2, in which the lubricant can be retained. Moreover, the concave part is not closed, and lubricating oil can freely enter and exit the concave part. Each star-shaped protrusion has a space from the adjacent star-shaped protrusion, and the spaces are inlets and outlets for the lubricating oil. This interval cannot be too wide, otherwise the dwell time of the lubricant in the recess is too short. Theoretical calculation and experimental verification prove that the length of the interval is required to be less than one third of the distance between the geometric centers of two adjacent star-shaped bulges.

The top surface of the star-shaped bulge is designed into a spherical surface, so that lubricating oil can also reach the top surface of the star-shaped bulge, and the spherical surface reduces the contact area between the piston and the cylinder wall, thereby further reducing friction. The edge of the top surface of the star-shaped bulge is provided with a round angle, and the section curve of the round angle is an elliptic line.

The height of the star-shaped bulges is 1 mm, and the length of the interval is one third of the distance between the geometric centers of the two adjacent star-shaped bulges. The surface of the wear-resistant structure is attached with a wear-resistant coating. The wear-resistant coating is a graphite layer, carbon fibers are distributed on the graphite layer, and the carbon fibers are distributed on the surface of the wear-resistant coating and in the inner part close to the surface.

Compared with the traditional concave structure, the shape and the function of the concave part provided by the utility model are different. The concave part is flush with the wall surface of the piston, and abrasive dust is not easy to remain; but is concave relative to the surrounding plurality of projections. The lubricating oil of the engine has a considerable viscosity, and the lubricating oil entering the concave part from the inlet and the outlet between the bulges can temporarily stay in the concave part, so that the lubricating oil is distributed on the whole wall surface of the piston during the stable work, wherein a large amount of lubricating oil is positioned in the concave part, and a small amount of lubricating oil is positioned on the top surface and the side surface of the bulge.

Any method realizes the wear-resisting structure of the aluminum-based piston skirt part, and the utility model discloses an within the scope of protection, a specific processing method is provided with regard to wear-resisting structure below.

The processing method of the wear-resistant structure of the aluminum-based piston skirt comprises the following steps:

step 1, processing star-shaped bulges on the metal surface of the skirt part of the aluminum-based piston according to the arrangement rule of the bulges. The basic shape of the protrusion can be machined rapidly and inexpensively by conventional or advanced manufacturing methods such as laser ablation, stamping, etching, etc.

And 2, processing a round angle on the edge of the top surface of the star-shaped bulge. This step may be performed by cutting and grinding or other machining processes.

And 3, adding a wear-resistant coating on the top surface of the star-shaped bulge or the whole surface of the piston skirt.

The substrate of the wear-resistant coating is made of graphite, the wear-resistant coating contains carbon fibers, and the carbon fibers are distributed on the surface of the wear-resistant coating and inside the surface close to the surface. As the wear resistant coating wears, the piston will be scrapped, and therefore the carbon fibers located deeper therein do not exert any wear enhancing effect. Therefore, the portion containing carbon fibers is within one third of the vertical thickness of the wear-resistant coating, as shown in fig. 3. Fig. 3 is a schematic cross-sectional view of the wear-resistant coating, with small black dots and lines at the top showing carbon fibers dispersed in graphite.

The preparation method of the carbon fiber reinforced graphite wear-resistant coating comprises the following steps:

step 1, adding magnetic particles on the surface of carbon fiber to obtain the magnetic carbon fiber. This section further includes the following subdivision steps:

step 1.1, carrying out ultrasonic treatment on carbon fibers in an acid solution; performing suction filtration, washing with deionized water, and repeating for multiple times until the filtrate is neutral; thus, an acid-washed carbon fiber was obtained. The acid solution is obtained by mixing nitric acid and sulfuric acid according to the mass ratio of 1: 1.

And step 1.2, fully mixing the carbon fiber after acid washing with an iron ion solution, then dropwise adding an alkaline solution into the iron ion solution until a large amount of precipitate is generated, and standing. The ferric ion solution is a mixed solution of ferric trichloride solution and ferrous chloride solution, wherein Fe³⁺With Fe²⁺Is 2:1, such a ratio may result in an iron-containing compound having magnetic properties. When the alkaline solution is dripped, the temperature of the iron ion solution is always kept at 80 ℃, which is beneficial to the full precipitation of iron ions.

Step 1.3, removing upper liquid; carrying out suction filtration on the lower-layer precipitate, washing with deionized water, and repeating for multiple times until the filtrate is neutral; thus, magnetic carbon fibers were obtained.

And 2, adding the magnetic carbon fibers into the graphite, fully and uniformly mixing the magnetic carbon fibers and the graphite, and coating the mixture on the skirt part of the piston to form a coating precursor. In order to sufficiently disperse the magnetic carbon fibers, the carbon fibers and graphite may be put together into a dispersion medium.

And 3, applying a magnetic field on the outer side of the piston skirt part to enable the magnetic carbon fibers to migrate and enrich towards the surface of the coating precursor and the inner part close to the surface. To accelerate the migration of the magnetic carbon fibers, ultrasonic oscillations may be applied to the piston skirt while rotating the magnetic field about the piston skirt.

And 4, sintering and solidifying the graphite under the protection of argon, wherein the carbon fiber is solidified. The sintering temperature was 2000 ℃.

In this embodiment, the four star-shaped protrusions of the skirt portion of the piston enclose a recessed area which serves as a reservoir for a portion of the lubricating oil. Along with the movement of the piston, the lubricating oil stored in the concave area can be quickly supplied to the surface of the wear-resistant coating of the star-shaped protrusion to play a lubricating role, the film forming property of the wear-resistant coating on the surface of the aluminum-based piston and the durability of an oil film layer attached during friction in a dry state are improved, and the friction coefficient of the skirt part of the aluminum-based piston is reduced.

The foregoing has described in detail preferred embodiments of the present invention. It should be understood that numerous modifications and variations can be devised by those skilled in the art in light of the teachings of the present invention without undue experimentation. Therefore, the technical solutions that can be obtained by a person skilled in the art through logic analysis, reasoning or limited experiments based on the prior art according to the concepts of the present invention should be within the scope of protection defined by the claims.

Claims

1. A wear-resistant structure for an aluminum-based piston skirt is characterized by comprising a plurality of star-shaped protrusions which are arranged on the surface of the piston skirt in a square matrix; the star shape of the star-shaped convex refers to that: the first arc line section is concave, and the second arc line section is convex.

2. A wear structure for an aluminum-based piston skirt as in claim 1, wherein said wear structure consists of only star-shaped protrusions.

3. A wear structure for an aluminum-based piston skirt as claimed in claim 2, wherein each star boss is spaced from an adjacent star boss.

4. A wear structure for an aluminum-based piston skirt as claimed in claim 3, wherein the length of said gap is less than one-third of the distance between the geometric centers of two adjacent ones of said star-shaped bosses.

5. A wear structure for an aluminum-based piston skirt as claimed in claim 2, wherein the top surface of said star-shaped projection is spherical.

6. A wear structure for an aluminum-based piston skirt as claimed in claim 5, wherein the edges of the top surfaces of said star shaped bosses are rounded.

7. A wear structure for an aluminum-based piston skirt as claimed in claim 6, wherein the sectional curve of said fillet is an elliptical line.

8. A wear structure for an aluminum-based piston skirt as claimed in claim 1, wherein a top surface of said wear structure is provided with a wear resistant coating.

9. The wear structure for an aluminum-based piston skirt according to claim 8, wherein said wear resistant coating has a thickness of 10 to 500 μm.

10. An aluminum-based piston, characterized in that the surface of the skirt portion of the aluminum-based piston is provided with a wear-resistant structure as claimed in any one of claims 1 to 9.