A method for forming a bore of a high-silicon aluminum alloy cylinder liner

Abstract

The application discloses a high-silicon aluminum alloy cylinder liner inner hole forming method, and belongs to the machining process of a diesel engine part. White corundum honing oil stones are selected as honing oil stones of a honing head to hone the high-silicon aluminum alloy cylinder liner inner hole. The honing process is divided into rough honing, semi-fine honing and platform net honing, so that a reinforced fine net surface with good oil storage performance of a microstructure is obtained. The application selects machining oil stones with high material matching, reasonably matches process parameters, and uses platform net honing forming processing mode, so that the oil storage performance and wear resistance of the working surface are ensured, the lubricity, wear resistance and anti-tension cylinder performance of the cylinder liner are improved on the basis of realizing the light weight of the cylinder liner, and the light weight and high reliability requirements of the diesel engine are met.

Description

Technical Field

[0001] This invention relates to the processing technology of diesel engine components, and in particular to a method for forming the inner bore of a cylinder liner. Background Technology

[0002] Currently, diesel engine cylinder liners are generally made of materials such as cast iron and steel. The development of lightweight cylinder liners using modern high-end manufacturing processes that are independently controllable can solve the problem of heavy diesel engine cylinder liners due to material limitations. This is of great significance for significantly reducing the weight of diesel engines and meeting the requirements for lightweight and high mobility.

[0003] With the development of diesel engine power towards higher power, higher explosion pressure, and higher reliability, new requirements have been placed on the working environment of the diesel engine combustion chamber. As a crucial component of the diesel engine power output system, the cylinder liner, along with the cylinder head, cylinder head gasket, piston, piston rings, and other parts, forms a closed combustion chamber. The cylinder liner, as an important part of the combustion chamber, must perform functions such as combustion chamber sealing, piston guidance, and heat transfer. The inner wall of the cylinder liner not only withstands repeated impacts from high-temperature loads and the intense alternating lateral pressures caused by the high-speed reciprocating motion of the piston, but also experiences continuous and intense friction caused by the high-speed sliding of the piston. In particular, the rapid development of diesel engine combustion system technologies such as high density, high explosion pressure, and high linear velocity has placed higher technical requirements on the load-bearing capacity, lubricity, anti-cracking properties, and wear resistance of the cylinder liner inner bore surface. Due to the technical characteristics of high-silicon aluminum alloy cylinder liners, such as thin walls, softness, and large clamping deformation, individual machining is difficult to control. Diesel engines have previously undergone direct boring and honing in the aluminum alloy engine block bores, but these methods have not achieved satisfactory results. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a method for forming the inner hole of a high-silicon aluminum alloy cylinder liner. The method involves selecting a machining oilstone with high material compatibility, reasonably matching process parameters, and using a platform textured honing process to ensure the oil retention and wear resistance of the working surface. This method improves the lubricity, wear resistance, and anti-cylinder scoring of the cylinder liner while achieving a lightweight design, thus meeting the requirements of lightweight and high reliability for diesel engines.

[0005] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0006] A method for forming the inner hole of a high-silicon aluminum alloy cylinder liner involves using a white corundum honing stone as the honing head to hone the inner hole of the high-silicon aluminum alloy cylinder liner. The honing process is divided into coarse honing, semi-fine honing, and plateau textured honing to obtain a reinforced fine textured surface with good oil storage performance.

[0007] A further improvement of the technical solution of this invention lies in the following: the three processes of coarse honing, semi-fine honing, and platform textured honing are matched with the corresponding honing stone materials, binders, and particle sizes. The main shaft speed, reciprocating speed, tension force, and number of honing cycles that drive the honing stone to rotate are adjusted to obtain different surface roughness parameters, thus obtaining a process flow corresponding to a strengthened fine textured surface with good oil storage performance in the surface microstructure.

[0008] A further improvement of the technical solution of the present invention is that: the honing stone used for the coarse honing of the inner hole is a white corundum abrasive strip bonded with 80 ceramic binders, the first-stage honing tension is 5 Bar, the second-stage honing tension is 4 Bar, the spindle speed is 118 r / min, the reciprocating speed is 17 m / min, and the roughness of the inner hole reaches Ra1~2.5 μm.

[0009] A further improvement of the technical solution of the present invention is that: the semi-fine honing uses a honing oilstone with 120 white corundum abrasive strips bonded by ceramic binder, the honing first-stage tension force is 6 Bar, the second-stage tension force is 5 Bar, the spindle speed is 120 r / min, the reciprocating speed is 17.3 m / min, the first-stage honing is performed twice, and the second-stage honing is performed twice.

[0010] A further improvement to the technical solution of this invention lies in the following: the platform honing uses a honing oilstone with 600 optimized ceramic binder-bonded white corundum abrasive strips. The first-stage honing tension is 5 Bar, the second-stage tension is 4 Bar, the spindle speed is 119 r / min, the reciprocating speed is 17.5 m / min, the first-stage honing is performed twice, and the second-stage honing is performed twice. The inner hole roughness reaches the parameters shown in the table below:

[0011]

[0012]

[0013] A further improvement of the technical solution of the present invention is that the silicon content in the cylinder liner alloy elements of the high silicon aluminum alloy cylinder liner is more than 20%.

[0014] The technological advancements achieved by this invention due to the adoption of the above technical solutions are as follows:

[0015] This invention selects and matches honing stones to find the most suitable material, binder, and particle size for high-silicon aluminum alloy cylinder liners. Simultaneously, honing process parameter experiments are conducted to create different combinations of tension force, spindle speed, reciprocating speed, and honing cycles. This optimizes the microstructure of the high-silicon aluminum alloy cylinder liner's inner bore surface, resulting in a fine-textured surface with good oil retention and high fatigue strength. This significantly improves the load-bearing capacity, wear resistance, and anti-cracking properties of the cylinder liner's inner bore, extending the service life of the diesel engine. At the same time, it drastically reduces the weight of the cylinder liner, meeting the overall lightweight requirements of the diesel engine. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the honing head structure of the present invention;

[0018] Figure 2 This is a schematic diagram of the microstructure of the reticulated honing process on the platform of this invention;

[0019] Figure 3 yes Figure 2 AA section view;

[0020] Figure 4 The cast iron cylinder liner (left) and the high silicon aluminum alloy cylinder liner (right) are honed with a textured pattern.

[0021] Among them, 1. main spindle push rod, 2. honing head cone, 3. honing stone base, 4. honing stone, and 5. return spring. Detailed Implementation

[0022] The present invention will be further described in detail below with reference to embodiments:

[0023] A method for forming the inner bore of a high-silicon aluminum alloy cylinder liner involves using a white corundum honing stone as the honing head to hone the inner bore of the high-silicon aluminum alloy cylinder liner. The honing process is divided into rough honing, semi-finish honing, and plateau textured honing. The silicon content in the high-silicon aluminum alloy cylinder liner alloy is above 20%. The specific process steps are as follows:

[0024] (1) Rough Honing: Rough honing of the inner hole is a process that minimizes honing time. Its processing condition directly affects the efficiency of subsequent platform honing. The honing stone used in this process is a white corundum abrasive strip with 80 ceramic binders. The honing tension is 5 Bar for the first stage and 4 Bar for the second stage. The spindle speed is 118 r / min and the reciprocating speed is 17 m / min. The inner hole roughness control standard is Ra1~2.5 μm.

[0025] (2) Semi-finish honing: Semi-finish honing is an important process for forming the desired internal hole surface texture structure. Its processing quality has a significant impact on the formation of honing parameters. In this process, honing oilstones are used with 120 white corundum abrasive strips bonded with ceramic binder. The honing first-stage tension is 6 Bar, the second-stage tension is 5 Bar, the spindle speed is 120 r / min, the reciprocating speed is 17.3 m / min, the first-stage honing is performed twice, and the second-stage honing is performed twice.

[0026] (3) Plateau honing: Plateau honing is the core process for achieving high-quality internal hole surface finish. After completion, it creates a textured surface with good oil retention, such as... Figure 2 , 3 As shown, the honing stone used in this process is a white corundum abrasive strip with 600 grains bonded by an optimized ceramic binder. The honing tension is 5 Bar for the first stage and 4 Bar for the second stage. The spindle speed is 119 r / min, the reciprocating speed is 17.5 m / min, and the first stage honing is performed twice, followed by the second stage honing twice. The inner hole roughness reaches the parameters shown in the table below:

[0027]

[0028]

[0029] This invention is carried out on a CNC vertical honing machine. The equipment's CNC control system controls the hydraulic cylinders to generate thrust, such as... Figure 1 As shown, the transmission to the spindle push rod 1 pushes the honing head cone 2 downward. The tapered inclined surface on the honing head cone 2 cooperates with the honing stone base 3 to push open the honing stone 4. The honing stone 4 acts on the cylinder liner. After honing is completed, the honing stone 4 is reset under the action of the pull spring 5. The inner hole honing process is completed under the control of the equipment program parameters.

[0030] This invention utilizes platform-type textured honing technology to complete the forming of the inner bore of a high-silicon aluminum alloy cylinder liner. This results in an optimal combination of roughness parameters, including Pt, Rz, Rmax, Ra, R3z, Wt(GS), Rdc(5-20), Rdc(20-80), Rdc(80-95), and RHSC. This optimizes the shape of the oil reservoir in the cylinder liner inner bore, significantly improving cylinder liner lubrication and anti-scoring performance, thus achieving the goal of lightweighting the diesel engine. Figure 4 As shown, the oil-retaining mesh pattern formed by the honing of the inner bore platform, combined with the unique uniformly distributed silicon-aluminum particles in the high-silicon aluminum alloy material, constitutes the microstructure of the cylinder liner inner bore surface, which integrates the smooth transition of the platform mesh pattern with the natural groove structure. Compared with the inner bore surface of traditional cast iron and steel cylinder liners, it is more conducive to the formation of an oil film on the inner wall, increasing the lubrication and wear resistance of the engine. Moreover, compared with traditional cast iron or steel cylinder liners, the high-silicon aluminum alloy cylinder liner has better thermal conductivity while meeting the strength requirements, which can effectively and quickly reduce the combustion chamber temperature. Compared with cast iron cylinder liners, a single high-silicon aluminum alloy cylinder liner can achieve a weight reduction of nearly 5 kg, and the overall engine weight reduction of nearly 30 kg, which has an important impact on the lightweighting of diesel engine power.

[0031] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A method for forming the inner bore of a high-silicon aluminum alloy cylinder liner, characterized in that: A white corundum honing stone was selected as the honing head for honing the inner bore of a high-silicon aluminum alloy cylinder liner. The honing process consisted of rough honing, semi-finish honing, and plateau-patterned honing. The silicon content in the high-silicon aluminum alloy cylinder liner alloy was above 20%. (1) The honing stone used for rough honing is a white corundum abrasive strip with 80 ceramic binders. The honing first-stage tension is 5 Bar, the second-stage tension is 4 Bar, the spindle speed is 118 r / min, and the reciprocating speed is 17 m / min. After rough honing, the inner hole roughness reaches Ra1~2.5 μm. (2) Semi-fine honing uses honing oilstones with 120 white corundum abrasive strips bonded with ceramic binder. The honing first-stage tension is 6 Bar, the second-stage tension is 5 Bar, the spindle speed is 120 r / min, and the reciprocating speed is 17.3 m / min. During semi-fine honing, the first-stage honing is performed twice, and the second-stage honing is performed twice. (3) The platform textured honing uses honing oilstones with 600 optimized ceramic binders bonded white corundum abrasive strips. The honing first-stage tension is 5 Bar, the second-stage tension is 4 Bar, the spindle speed is 119 r / min, and the reciprocating speed is 17.5 m / min. During platform honing, the first-stage honing is performed twice, and the second-stage honing is performed twice. The internal surface roughness should meet the parameters shown in the table below: Ultimately, a reinforced, finely textured surface with good oil storage performance is obtained.

Images