Cam bearing seat structure and processing method thereof, engine and vehicle

Abstract

The present application discloses a cam bearing seat structure and a processing method thereof, as well as an engine and a vehicle, relating to the field of vehicle technology. The structure comprises a bearing base and a bearing cover, wherein the bearing base and the bearing cover form a camshaft hole for mounting a cam, and the sidewall of the camshaft hole has a lubricating oil groove. The raw material composition of the cam bearing seat structure comprises, by mass fraction, the following: Si: 11.5% to 14.5%; Mg: 0.35% to 0.45%; Mn: 0.35% to 0.50%; Ti: 0.06% to 0.12%; Sr: 0.015% to 0.025%; Zr: 0.01% to 0.1%; the remainder being Al and unavoidable impurities. By changing the raw material composition of the cam bearing seat structure, the weight of the cam bearing seat structure can be reduced, allowing the upper cover and base of the cam bearing seat structure to be processed using the same material while meeting the different load-bearing and wear-resistant requirements of the upper cover and base of the cam bearing seat structure. This eliminates the need for a bushing between the upper cover and base of the cam bearing seat structure and the camshaft.

Description

Technical Field

[0001] The present application relates to the field of vehicle technology, and in particular to a cam bearing seat structure and a processing method thereof, an engine and a vehicle. Background Art

[0002] The traditional heavy-duty diesel engine cam bearing seat assembly consists of two parts: a base and an upper cover. The base usually only bears pressure, so it is generally made of cast iron to meet the strength requirements. The upper seat needs to have a higher body strength because it needs to assemble the intake and exhaust rocker arm shafts. If the engine has an exhaust brake function, the upper cover body strength requirements are even higher, so the upper cover is usually made of high-grade ductile iron or forged steel.

[0003] The camshaft rotates in the cam bearing bore, which is formed by the base and the upper cover. Camshafts are typically manufactured from chilled cast iron or carbon steel. This results in severe wear between the camshaft and the cam bearing housing, even when lubricated with oil. Therefore, the cam bearing bores of traditional steel or iron cam bearing housing assemblies require aluminum-based bimetallic bushings.

[0004] On the one hand, the aluminum-based bimetallic bushing increases the weight of the entire vehicle body and does not meet the requirements of lightweighting. On the other hand, under special working conditions, there is a situation where polishing causes shaft seizure. In addition, the lubricating oil channel on the aluminum-based bimetallic bushing is slender, making processing difficult and easily causing tool wear. Summary of the Invention

[0005] The present application provides a cam bearing seat structure and a processing method thereof, an engine and a vehicle to solve the problems that the existing aluminum-based bimetallic bushing increases the weight of the entire vehicle body and does not meet the lightweight requirements on the one hand, and on the other hand, there is a situation where the shaft is stuck due to polishing under special working conditions, and the lubricating oil channel on the aluminum-based bimetallic bushing is slender, which makes processing difficult and easily causes tool wear.

[0006] In a first aspect, the present application provides a cam bearing seat structure, comprising a bearing base and a bearing upper cover, wherein the bearing base and the bearing upper cover form a camshaft hole for mounting a cam, and the side wall of the camshaft hole has a lubricating oil groove, wherein:

[0007] Calculated by mass fraction, the raw material composition of the cam bearing seat structure includes: Si: 11.5% to 14.5%; Mg: 0.35% to 0.45%; Mn: 0.35% to 0.50%; Ti: 0.06% to 0.12%; Sr: 0.015% to 0.025%; Zr: 0.01% to 0.1%; the remainder is Al and unavoidable impurities.

[0008] By modifying the raw material composition of the cam bearing seat structure, this application reduces the weight of the cam bearing seat structure, enabling the upper cover and base of the cam bearing seat structure to be machined from the same material, simplifying the process. Furthermore, the application simultaneously meets the different load-bearing and wear-resistance requirements of the upper cover and base of the cam bearing seat structure, eliminating the need for bushings between the upper cover and base of the cam bearing seat structure and the camshaft, thereby reducing the use of bushings. Within this range, the Si mass fraction achieves good fluidity and wear resistance for the cam bearing seat casting. Within this range, the Mg mass fraction achieves optimal yield strength and elongation through solution treatment and artificial aging. Within this range, the Mn mass fraction provides excellent anti-mold properties and forms a "Chinese character"-shaped Fe-Mn compound with the Fe incorporated into the alloy, thereby reducing the negative impact of the acicular Fe lattice structure on the matrix structure, which reduces the yield strength and elongation of the material. Within this range, the Ti mass fraction refines the microstructure and achieves a grain size of 7-8, thereby achieving good yield strength. Within this range, the Sr mass fraction achieves a good modification effect, thereby improving the yield strength of the material. When the mass fraction of Zr is within this range, the recrystallization temperature of the alloy can be increased, thereby improving the high-temperature strength of the material.

[0009] It should be noted that since the bushing structure has been eliminated, to reduce friction and shaft seizure between the camshaft and the cam bearing seat, a lubricating oil groove is provided on the sidewall of the camshaft hole. This protects the camshaft and cam bearing seat from the lubricating oil, reducing hard friction. Specifically, as an example, the lubricating oil supply pressure can be 0.68-0.72MPa, and the lubricating oil temperature can be 80-120°C.

[0010] To further improve the reliability of the upper cover and base of the cam bearing seat structure, in actual use, the maximum linear velocity between the camshaft and the cam bearing seat is usually less than or equal to 10m / s. This can increase the service life of the upper cover and base of the cam bearing seat structure.

[0011] In some embodiments, the metallographic structure of the cam bearing seat structure includes an α-Al phase and a eutectic silicon phase. The eutectic silicon phase is relatively hard, while the α-Al phase is relatively soft. The cam bearing seat structure contains both a relatively soft phase that acts as a lubricant and a relatively hard phase that acts as a wear-resistant phase, thereby achieving different load-bearing and wear-resistant requirements for the upper cover and base of the cam bearing seat structure, so that there is no need to set a bushing between the upper cover and base of the cam bearing seat structure and the camshaft, reducing the use of bushings. The upper cover and base of the cam bearing seat structure can be processed with the same material, simplifying the process.

[0012] In some embodiments, the mass ratio of Si to Al is (13-17): 100. Suitable α-Al phase and eutectic silicon phase can be formed, thereby improving the wear resistance and strength of the parts, and obtaining better wear resistance and sapphire fatigue performance.

[0013] In some embodiments, the cam bearing seat structure has a load capacity of 0.1 to 100 MPa. Within this load capacity range, the cam bearing seat structure can be made of the same material for its upper cover and base. Without requiring a bushing between the upper cover and base of the cam bearing seat structure and the camshaft, the upper cover and base of the cam bearing seat structure maintain their respective load requirements, thereby reducing wear and failure of the upper cover and base of the cam bearing seat structure and improving the reliability of the upper cover and base of the cam bearing seat structure.

[0014] In a second aspect, the present application provides a method for processing a cam bearing seat structure, comprising the following steps:

[0015] Mixing and melting the raw materials according to their composition to obtain an aluminum alloy melt;

[0016] The aluminum alloy melt is refined, deslagging, degassing, modifying and cooling to obtain a pretreated melt;

[0017] Casting the pretreated solution into a mold and demoulding it to obtain a prefabricated part;

[0018] The prefabricated part is subjected to solution treatment, quenching and aging treatment to obtain a cam bearing seat structure.

[0019] By changing the raw material composition of the cam bearing seat structure, on the one hand, the weight of the cam bearing seat structure can be reduced, so that the upper cover and the base of the cam bearing seat structure can be processed with the same material, simplifying the process, and at the same time, it can meet the different load-bearing and wear-resistant requirements of the upper cover and the base of the cam bearing seat structure, so that there is no need to set a bushing between the upper cover and the base of the cam bearing seat structure and the camshaft, reducing the use of bushings.

[0020] In some embodiments, the pretreated solution is molded and demolded to obtain a preform, wherein the mold is filled with a graphite powder layer, wherein:

[0021] The particle size of the graphite powder is 800 to 1000 nm; and / or,

[0022] The thickness of the graphite powder layer is 40 to 50 μm.

[0023] Specifically, a layer of graphite powder is applied to the mold surface using an electrostatic spraying process. The mold is then closed, and the treated aluminum alloy melt is pushed upward through a riser tube from a holding furnace below the mold using high-purity nitrogen gas. The graphite powder particle size and thickness within this range facilitate demolding and create a smoother, flatter surface.

[0024] The specific molding process may be that after the aluminum alloy melt fills the mold cavity, the central extrusion column above the mold gate begins to descend and closes the mold gate to complete the filling process. At this time, the high-purity nitrogen gas in the insulation furnace is depressurized, and the excess aluminum alloy melt in the riser returns to the insulation furnace. The central extrusion column is further descended to extrude all the aluminum alloy melt below the shoulder of the central extrusion column into the mold cavity of the mold forming casting part, and the aluminum alloy melt is demolded after it is completely solidified. The central extrusion column includes an upper end and a lower end of the extrusion column. The diameter of the upper end of the central extrusion column is larger than the diameter of the lower end, and the diameter of the upper end of the central extrusion column is 1.8 to 2.0 times the diameter of the lower end; the diameter of the lower end of the central extrusion column is adapted to the diameter of the mold gate; the slope of the transition zone between the upper end and the lower end of the central extrusion column is 45° to 60°; the extrusion pressure of the central extrusion column is 60MPa to 90MPa. The surface of the central extrusion column is sprayed with a graphite powder coating with a particle size of 800nm ​​to 1000nm and a thickness of 40μm to 50μm.

[0025] In some embodiments, the preform is subjected to solution treatment, quenching, and aging treatment to obtain a cam bearing seat structure:

[0026] The solution temperature is 500-540°C; and / or,

[0027] The solution time is 2 to 4 hours; and / or,

[0028] The aging temperature is 160-180°C; and / or

[0029] The aging time is 2 to 4 hours.

[0030] Under these solution temperature, solution time, aging temperature, and aging time conditions, the cam bearing seat structure can contain both a relatively soft phase for lubrication and a relatively hard phase for wear resistance, thereby meeting the different load-bearing and wear-resistance requirements of the upper cover and base of the cam bearing seat structure. This eliminates the need for bushings between the upper cover and base of the cam bearing seat structure and the camshaft, reducing the use of bushings. This allows the upper cover and base of the cam bearing seat structure to be processed from the same material, simplifying the process.

[0031] In some embodiments, the cam bearing seat structure is obtained by subjecting the preform to solution treatment, quenching, and aging treatment. The quenching treatment includes water quenching, wherein:

[0032] The water quenching temperature is 70-90°C; and / or,

[0033] The water quenching time is 8 to 15 minutes.

[0034] Water quenching allows the cam bearing seat to achieve higher comprehensive mechanical properties. This water quenching temperature allows for a higher cooling rate, reducing the precipitation of strengthening phases from the solid solution, resulting in excellent strengthening effects.

[0035] In a third aspect, the present application provides an engine, comprising the cam bearing seat structure described in the first aspect, or a cam bearing seat structure manufactured by the processing method of the cam bearing seat structure of the second aspect.

[0036] In a fourth aspect, the present application provides a vehicle comprising the parts of the third aspect. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0038] Figure 1 This is a structural diagram of a cam bearing seat according to an embodiment of the present application.

[0039] Figure 2 This is a metallographic diagram of the cam bearing seat structure according to an embodiment of the present application.

[0040] Description of Figure Numbers:

[0041] 100 cam bearing seat structure; 1 bearing base; 2 bearing upper cover; 3 camshaft hole; 31 lubricating oil groove. DETAILED DESCRIPTION

[0042] To make the objectives, technical solutions, and advantages of this application more clear, the technical solutions of this application will be clearly and completely described below in conjunction with the embodiments of this application. Obviously, the embodiments described are part of the embodiments of this application, not all of them. All other embodiments obtained by ordinary technicians in this field based on the embodiments of this application without making any creative efforts shall fall within the scope of protection of this application.

[0043] The traditional heavy-duty diesel engine cam bearing seat assembly consists of two parts: a base and an upper cover. The base usually only bears pressure, so it is generally made of cast iron to meet the strength requirements. The upper seat needs to have a higher body strength because it needs to assemble the intake and exhaust rocker arm shafts. If the engine has an exhaust brake function, the upper cover body strength requirements are even higher, so the upper cover is usually made of high-grade ductile iron or forged steel.

[0044] The camshaft rotates in the cam bearing bore, which is formed by the base and the upper cover. Camshafts are typically manufactured from chilled cast iron or carbon steel. This results in severe wear between the camshaft and the cam bearing housing, even when lubricated with oil. Therefore, the cam bearing bores of traditional steel or iron cam bearing housing assemblies require aluminum-based bimetallic bushings.

[0045] On the one hand, the aluminum-based bimetallic bushing increases the weight of the entire vehicle body and does not meet the requirements of lightweighting. On the other hand, under special working conditions, there is a situation where polishing causes shaft seizure. In addition, the lubricating oil channel on the aluminum-based bimetallic bushing is slender, making processing difficult and easily causing tool wear.

[0046] Traditional forged steel or cast iron camshaft bearing assemblies require an aluminum-based bimetallic bushing in the camshaft bearing bore. This bushing consists of a wear-resistant layer and a steel backing layer. The wear-resistant layer contacts the camshaft, while the steel backing layer contacts the camshaft bearing bore. The wear-resistant layer is an AlSn20Cu alloy with a thickness of 0.2 to 0.5 mm. The steel backing layer, which provides support, is 0.8Al with a thickness of 1 to 4 mm. In actual engineering applications, during cold engine starts, the camshaft bore lubricant fails to be pumped into the bushing in time, resulting in brief dry friction and causing engine malfunction.

[0047] In view of this, the present application provides a cam bearing seat structure and its processing method, engine and vehicle to solve the problem that the existing aluminum-based bimetallic bushing increases the weight of the entire vehicle body and does not meet the requirements of lightweighting. On the other hand, under special working conditions, there is a situation where polishing causes shaft seizure, and the lubricating oil channel on the aluminum-based bimetallic bushing is slender, difficult to process, and easily causes tool wear.

[0048] like Figure 1 As shown, in a first aspect, the present application provides a cam bearing seat structure 100, comprising a bearing base 1 and a bearing upper cover 2, wherein the bearing base 1 and the bearing upper cover 2 form a camshaft hole 3 for mounting a cam, and the side wall of the camshaft hole 3 has a lubricating oil groove 31, wherein:

[0049] In terms of mass fraction, the raw material composition of the cam bearing seat structure 100 includes: Si: 11.5% to 14.5%; Mg: 0.35% to 0.45%; Mn: 0.35% to 0.50%; Ti: 0.06% to 0.12%; Sr: 0.015% to 0.025%; Zr: 0.01% to 0.1%; the remainder is Al and unavoidable impurities.

[0050] By changing the raw material composition of the cam bearing seat structure 100, the present application can reduce the weight of the cam bearing seat structure, allowing the upper cover and base of the cam bearing seat structure 100 to be processed from the same material, simplifying the process. At the same time, it can simultaneously meet the different load-bearing and wear-resistant requirements of the upper cover and base of the cam bearing seat structure 100, eliminating the need for a bushing between the upper cover and base of the cam bearing seat structure 100 and the camshaft, reducing the use of bushings. Within this range of Si mass fraction, good wear resistance can be achieved, making it possible to eliminate bushings. Within this range of Mg mass fraction, the material can achieve optimal yield strength and elongation through solution treatment + artificial aging. Within this range of Mn mass fraction, the material can achieve good anti-sticking properties while also forming "Chinese character"-shaped Fe-Mn compounds with Fe incorporated into the alloy, thereby reducing the negative impact of the lattice structure of needle-shaped Fe relative to the matrix structure, which reduces the yield strength and elongation of the material. Within this range of Ti mass fraction, the microstructure can be refined and a grain size of 7-8 can be achieved, thereby achieving good yield strength. A Sr mass fraction within this range achieves a good modification effect, thereby improving the material's yield strength. A Zr mass fraction within this range increases the alloy's recrystallization temperature, thereby enhancing the material's high-temperature strength. The lubricating oil groove 31 is located on the sidewall of the camshaft hole 3, making it easier to machine and facilitating the flow of lubricating oil, thereby reducing the risk of shaft seizure.

[0051] It should be noted that since the bushing structure has been eliminated, a lubricating oil groove 31 is provided on the sidewall of the camshaft hole 3 to reduce friction and shaft seizure between the camshaft and the cam bearing seat. This protects the camshaft and cam bearing seat from the lubricating oil, reducing hard friction. Specifically, as an example, the lubricating oil supply pressure can be 0.68-0.72 MPa, and the lubricating oil temperature can be 80-120°C.

[0052] To further improve the reliability of the upper cover and base of the cam bearing seat structure 100, in actual use, the maximum linear velocity between the camshaft and the cam bearing seat is generally less than or equal to 10 m / s, thereby increasing the service life of the upper cover and base of the cam bearing seat structure 100.

[0053] like Figure 2As shown, in combination with the first aspect, in some embodiments provided in the present application, the metallographic structure of the cam bearing seat structure 100 includes an α-Al phase and a eutectic silicon phase. The eutectic silicon phase is relatively hard, while the α-Al phase is relatively soft. The cam bearing seat structure 100 has both a relatively soft phase that plays a lubricating role and a relatively hard phase that plays a wear-resistant role in its structure, thereby achieving different load-bearing and wear-resistant requirements for the upper cover and base of the cam bearing seat structure 100, so that there is no need to set a bushing between the upper cover and base of the cam bearing seat structure 100 and the camshaft, reducing the use of bushings. The upper cover and base of the cam bearing seat structure 100 can be processed with the same material, simplifying the process.

[0054] In conjunction with the first aspect, in some embodiments provided herein, the mass ratio of Si to Al is (13-17):100. This allows for the formation of suitable α-Al phases and eutectic silicon phases, thereby simultaneously improving the wear resistance and strength of the parts, and achieving better wear resistance and sapphire fatigue performance.

[0055] In conjunction with the first aspect, in some embodiments provided herein, the cam bearing seat structure 100 has a load capacity of 0.1 to 100 MPa. The load capacity of the cam bearing seat structure 100 is within this range, which can further enable the upper cover and base of the cam bearing seat structure 100 to be processed from the same material. Without the need for a bushing between the upper cover and base of the cam bearing seat structure 100 and the camshaft, the upper cover and base of the cam bearing seat structure 100 maintain their respective different load requirements, thereby reducing wear and failure of the upper cover and base of the cam bearing seat structure 100 and improving the reliability of the upper cover and base of the cam bearing seat structure 100.

[0056] In a second aspect, the present application provides a method for processing a cam bearing seat structure, comprising the following steps:

[0057] Mixing and melting the raw materials according to their composition to obtain an aluminum alloy melt;

[0058] The aluminum alloy melt is refined, deslagging, degassing, modifying and cooling to obtain a pretreated melt;

[0059] Casting the pretreated solution into a mold and demoulding it to obtain a prefabricated part;

[0060] The prefabricated part is subjected to solution treatment, quenching and aging treatment to obtain a cam bearing seat structure.

[0061] By changing the raw material composition of the cam bearing seat structure, on the one hand, the weight of the cam bearing seat structure can be reduced, so that the upper cover and the base of the cam bearing seat structure can be processed with the same material, simplifying the process, and at the same time, it can meet the different load-bearing and wear-resistant requirements of the upper cover and the base of the cam bearing seat structure, so that there is no need to set a bushing between the upper cover and the base of the cam bearing seat structure and the camshaft, reducing the use of bushings.

[0062] In combination with the second aspect, in some embodiments provided in the present application, the pretreated solution is molded and demolded to obtain a preform, and the mold is filled with a graphite powder layer, wherein the particle size of the graphite powder is 800 to 1000 nm.

[0063] In combination with the second aspect, in some embodiments provided in the present application, the pretreated solution is molded and demolded to obtain a preform, and the mold is filled with a graphite powder layer, wherein the thickness of the graphite powder layer is 40 to 50 μm.

[0064] Specifically, a layer of graphite powder is applied to the mold surface using an electrostatic spraying process. The mold is then closed, and the treated aluminum alloy melt is pushed upward through a riser tube from a holding furnace below the mold using high-purity nitrogen gas. The graphite powder particle size and thickness within this range facilitate demolding and create a smoother, flatter surface.

[0065] The specific molding process may be that after the aluminum alloy melt fills the mold cavity, the central extrusion column above the mold gate begins to descend and closes the mold gate to complete the filling process. At this time, the high-purity nitrogen gas in the insulation furnace is depressurized, and the excess aluminum alloy melt in the riser returns to the insulation furnace. The central extrusion column is further descended to extrude all the aluminum alloy melt below the shoulder of the central extrusion column into the mold cavity of the mold forming casting part, and the aluminum alloy melt is demolded after it is completely solidified. The central extrusion column includes an upper end and a lower end of the extrusion column. The diameter of the upper end of the central extrusion column is larger than the diameter of the lower end, and the diameter of the upper end of the central extrusion column is 1.8 to 2.0 times the diameter of the lower end; the diameter of the lower end of the central extrusion column is adapted to the diameter of the mold gate; the slope of the transition zone between the upper end and the lower end of the central extrusion column is 45° to 60°; the extrusion pressure of the central extrusion column is 60MPa to 90MPa. The surface of the central extrusion column is sprayed with a graphite powder coating with a particle size of 800nm ​​to 1000nm and a thickness of 40μm to 50μm.

[0066] In combination with the second aspect, in some embodiments provided in the present application, the preform is subjected to solution treatment, quenching, and aging treatment to obtain a cam bearing seat structure: the solution temperature is 500-540°C.

[0067] In combination with the second aspect, in some embodiments provided in the present application, the preform is subjected to solution treatment, quenching, and aging treatment to obtain a cam bearing seat structure: the solution treatment time is 2 to 4 hours.

[0068] In combination with the second aspect, in some embodiments provided in the present application, the preform is subjected to solution treatment, quenching, and aging treatment to obtain a cam bearing seat structure: the aging temperature is 160-180°C.

[0069] In combination with the second aspect, in some embodiments provided in the present application, the preform is subjected to solution treatment, quenching, and aging treatment to obtain a cam bearing seat structure: the aging time is 2 to 4 hours.

[0070] Under these solution temperature, solution time, aging temperature, and aging time conditions, the cam bearing seat structure can contain both a relatively soft phase for lubrication and a relatively hard phase for wear resistance, thereby meeting the different load-bearing and wear-resistance requirements of the upper cover and base of the cam bearing seat structure. This eliminates the need for bushings between the upper cover and base of the cam bearing seat structure and the camshaft, reducing the use of bushings. This allows the upper cover and base of the cam bearing seat structure to be processed from the same material, simplifying the process.

[0071] In combination with the second aspect, in some embodiments provided in the present application, the preform is subjected to solution treatment, quenching, and aging treatment to obtain a cam bearing seat structure, and the quenching treatment method includes water quenching, wherein: the water quenching temperature is 70 to 90°C.

[0072] In combination with the second aspect, in some embodiments provided in the present application, the preform is subjected to solution treatment, quenching, and aging treatment to obtain a cam bearing seat structure, and the quenching treatment method includes water quenching, wherein: the water quenching time is 8 to 15 minutes.

[0073] Water quenching can allow the cam bearing seat to obtain higher comprehensive mechanical properties. At this water quenching temperature and water quenching time, a higher cooling rate can be obtained at this water quenching and temperature, preventing the strengthening phase from precipitating from the solid solution, thereby obtaining a better strengthening effect. In a third aspect, the present application provides an engine, comprising the cam bearing seat structure described in the first aspect, or a cam bearing seat structure processed by the processing method of the cam bearing seat structure of the second aspect. The engine has all the beneficial effects of the cam bearing seat structure, and this application will not repeat them one by one here.

[0074] In a fourth aspect, the present application provides a vehicle comprising the components of the third aspect. The vehicle has all the beneficial effects of the cam bearing seat structure, which will not be described in detail herein.

[0075] The technical solution provided in this application is described in detail below with reference to embodiments.

[0076] Example 1

[0077] Embodiment 1 of the present application provides a method for processing a cam bearing seat structure, comprising the following steps:

[0078] The raw material composition of the cam bearing seat structure is as follows: Si: 11.5%; Mg: 0.4%; Mn: 0.35%; Ti: 0.06%; Sr: 0.015%; Zr: 0.01%; the balance is Al and unavoidable impurities;

[0079] Adding raw materials into a melting furnace according to the respective components and melting them to obtain an aluminum alloy melt;

[0080] The aluminum alloy melt is subjected to refining, slagging, degassing, modification and cooling treatment;

[0081] The mold is preheated. After reaching the set temperature of 170°C, a layer of graphite powder is sprayed on the mold surface using an electrostatic spraying process. The mold is then closed, and the treated aluminum alloy melt is pushed from the holding furnace below the mold along the riser tube into the mold cavity from bottom to top using high-purity nitrogen gas. The graphite powder has a particle size of 800nm ​​and the spraying thickness is 40μm.

[0082] After the aluminum alloy melt fills the mold cavity, the central extrusion column above the mold gate begins to descend and closes the inner gate to complete the filling process. At this time, the high-purity nitrogen in the insulation furnace is depressurized, and the excess aluminum alloy melt in the riser returns to the insulation furnace. The central extrusion column is further moved downward to extrude all the aluminum alloy melt below the shoulder of the central extrusion column into the mold cavity of the mold forming casting part, and the aluminum alloy melt is demolded after it is completely solidified and formed. The central extrusion column includes an upper end and a lower end of the extrusion column. The diameter of the upper end of the central extrusion column is 1.8 times the diameter of the lower end, and the diameter of the lower end of the central extrusion column matches the diameter of the mold inner gate; the extrusion pressure of the central extrusion column is 60MPa;

[0083] The casting obtained after demoulding is heat treated to obtain a cam bearing seat assembly casting blank; the casting blank is solution treated at a solution temperature of 500°C and a solution time of 2 hours, the casting is water quenched at a water temperature of 70°C and a water quenching time of 8 minutes, and then the casting is artificially aged at an aging temperature of 160°C and an aging time of 2 hours.

[0084] Example 2

[0085] Embodiment 2 of the present application provides a method for processing a cam bearing seat structure, comprising the following steps:

[0086] The raw material composition of the cam bearing seat structure is as follows: Si: 14.5%; Mg: 0.45%; Mn: 0.50%; Ti: 0.12%; Sr: 0.025%; Zr: 0.1%; the balance is Al and unavoidable impurities;

[0087] Adding raw materials into a melting furnace according to the respective components and melting them to obtain an aluminum alloy melt;

[0088] The aluminum alloy melt is subjected to refining, slagging, degassing, modification and cooling treatment;

[0089] The mold is preheated. After reaching the set temperature of 180°C, a layer of graphite powder is sprayed on the mold surface using an electrostatic spraying process. The mold is then closed, and the treated aluminum alloy melt is pushed from the insulation furnace below the mold along the riser tube into the mold cavity from bottom to top using high-purity nitrogen gas. The graphite powder particle size is 1000nm, and the spraying thickness is 50μm.

[0090] After the aluminum alloy melt fills the mold cavity, the central extrusion column above the mold gate begins to descend and closes the inner gate to complete the filling process. At this time, the high-purity nitrogen in the insulation furnace is depressurized, and the excess aluminum alloy melt in the riser returns to the insulation furnace. The central extrusion column is further moved downward to extrude all the aluminum alloy melt below the shoulder of the central extrusion column into the mold cavity of the mold forming casting part, and the aluminum alloy melt is demolded after it is completely solidified and formed. The central extrusion column includes an upper end and a lower end of the extrusion column. The diameter of the upper end of the central extrusion column is 2.0 times the diameter of the lower end, and the diameter of the lower end of the central extrusion column matches the diameter of the mold inner gate. The extrusion pressure of the central extrusion column is 90MPa.

[0091] The casting obtained after demoulding is heat treated to obtain a cam bearing seat assembly casting blank; the casting blank is solution treated at a solution temperature of 540°C and a solution time of 4 hours, the casting is water quenched at a water temperature of 90°C and a water quenching time of 15 minutes, and then the casting is artificially aged at an aging temperature of 180°C and an aging time of 4 hours.

[0092] Example 3

[0093] Embodiment 3 of the present application provides a method for processing a cam bearing seat structure, comprising the following steps:

[0094] The raw material composition of the cam bearing seat structure is as follows: Si: 12.5%; Mg: 0.35%; Mn: 0.45%; Ti: 0.11%; Sr: 0.02%; Zr: 0.05%; the balance is Al and unavoidable impurities;

[0095] Adding raw materials into a melting furnace according to the respective components and melting them to obtain an aluminum alloy melt;

[0096] The aluminum alloy melt is subjected to refining, slagging, degassing, modification and cooling treatment;

[0097] The mold is preheated. After reaching the set temperature of 190°C, a layer of graphite powder is sprayed on the mold surface using an electrostatic spraying process. The mold is then closed, and the treated aluminum alloy melt is pushed from the holding furnace below the mold along the riser tube into the mold cavity from bottom to top using high-purity nitrogen gas. The graphite powder particle size is 900nm, and the spraying thickness is 45μm.

[0098] After the aluminum alloy melt fills the mold cavity, the central extrusion column above the mold gate begins to descend and closes the inner gate to complete the filling process. At this time, the high-purity nitrogen in the insulation furnace is depressurized, and the excess aluminum alloy melt in the riser returns to the insulation furnace. The central extrusion column is further moved downward to extrude all the aluminum alloy melt below the shoulder of the central extrusion column into the mold cavity of the mold forming casting part, and the aluminum alloy melt is demolded after it is completely solidified and formed. The central extrusion column includes an upper end and a lower end of the extrusion column. The diameter of the upper end of the central extrusion column is 1.8 times the diameter of the lower end, and the diameter of the lower end of the central extrusion column matches the diameter of the mold inner gate; the extrusion pressure of the central extrusion column is 85MPa;

[0099] The casting obtained after demoulding is heat treated to obtain a cam bearing seat assembly casting blank; the casting blank is solution treated at a solution temperature of 520°C and a solution time of 3 hours, the casting is water quenched at a water temperature of 80°C and a water quenching time of 9 minutes, and then the casting is artificially aged at an aging temperature of 175°C and an aging time of 3.5 hours.

[0100] Example 4

[0101] Embodiment 4 of the present application provides a method for processing a cam bearing seat structure, comprising the following steps:

[0102] The raw material composition of the cam bearing seat structure is as follows: Si: 13.5%; Mg: 0.45%; Mn: 0.35%; Ti: 0.1%; Sr: 0.02%; Zr: 0.08%; the balance is Al and unavoidable impurities;

[0103] Adding raw materials into a melting furnace according to the respective components and melting them to obtain an aluminum alloy melt;

[0104] The aluminum alloy melt is subjected to refining, slagging, degassing, modification and cooling treatment;

[0105] The mold is preheated. After reaching the set temperature of 190°C, a layer of graphite powder is sprayed on the mold surface using an electrostatic spraying process. The mold is then closed, and the treated aluminum alloy melt is pushed from the holding furnace below the mold along the riser tube into the mold cavity from bottom to top using high-purity nitrogen gas. The graphite powder particle size is 900nm, and the spraying thickness is 45μm.

[0106] After the aluminum alloy melt fills the mold cavity, the central extrusion column above the mold gate begins to descend and closes the inner gate to complete the filling process. At this time, the high-purity nitrogen in the insulation furnace is depressurized, and the excess aluminum alloy melt in the riser returns to the insulation furnace. The central extrusion column is further moved downward to extrude all the aluminum alloy melt below the shoulder of the central extrusion column into the mold cavity of the mold forming casting part, and the aluminum alloy melt is demolded after it is completely solidified and formed. The central extrusion column includes an upper end and a lower end of the extrusion column. The diameter of the upper end of the central extrusion column is 1.8 times the diameter of the lower end, and the diameter of the lower end of the central extrusion column matches the diameter of the mold inner gate; the extrusion pressure of the central extrusion column is 85MPa;

[0107] The casting obtained after demoulding is heat treated to obtain a cam bearing seat assembly casting blank; the casting blank is solution treated at a solution temperature of 520°C and a solution time of 3 hours, the casting is water quenched at a water temperature of 80°C and a water quenching time of 9 minutes, and then the casting is artificially aged at an aging temperature of 175°C and an aging time of 3.5 hours.

[0108] Comparative Example 1

[0109] Comparative Example 1 of the present application provides a method for processing a cam bearing seat structure, which is similar to Example 1, except that Comparative Example 1 does not contain Si.

[0110] Comparative Example 2

[0111] Comparative Example 2 of the present application provides a method for processing a cam bearing seat structure, which is similar to Example 1, except that the mass fraction of Si in Comparative Example 2 is 10%.

[0112] Comparative Example 3

[0113] Comparative Example 3 of the present application provides a method for processing a cam bearing seat structure, which is similar to Example 1, except that the mass fraction of Si in Comparative Example 3 is 15%.

[0114] The cam bearing seat structures obtained by the processing methods of Examples 1 to 4 and Comparative Examples 1 to 3 were subjected to performance testing to test their yield strength, elongation, and wear resistance. The yield strength and elongation were measured according to GB / T 288, Metallic Materials, Room Temperature Tensile Test Method. The wear resistance test was conducted using a pin-on-disc friction and wear tester. The test method was as follows: ultrasonic cleaning for 10 minutes was performed before the test, followed by drying. The mass before wear was measured using a high-precision electronic scale (accuracy 0.00001g). Lubrication was regularly checked during the wear process. The lubricant was fully synthetic SAE 5W 30. After wear, the sample was ultrasonically cleaned in an acetone solution for 10 minutes, dried, and weighed. The wear mass of the sample was obtained by the difference in mass before and after wear. The wear time was 1 hour, the load was 20N, the wear diameter was 10mm, and the rotation speed was 400r / min. The results are shown in Table 1.

[0115] Table 1 Performance of the cam bearing seat structure of Examples 1 to 4 and Comparative Examples 1 to 3

[0116] Yield strength / MPa Elongation / % Wear amount / mg Example 1 215 5.2 0.30 Example 2 223 4.4 0.12 Example 3 265 8.5 0.23 Example 4 244 6.3 0.18 Comparative Example 1 238 9.5 3.02 Comparative Example 2 220 5.6 1.35 Comparative Example 3 188 5.2 0.11

[0117] As can be seen from Table 1, compared with Comparative Examples 1 to 3, the metallographic structure of the cam bearing seat structure in Examples 1 to 4 includes an α-Al phase and a eutectic silicon phase. The eutectic silicon phase is relatively hard, while the α-Al phase is relatively soft. The cam bearing seat structure contains both a relatively soft phase that acts as a lubricant and a relatively hard phase that acts as a wear-resistant phase, thereby achieving the different load-bearing and wear-resistant requirements of the upper cover and base of the cam bearing seat structure. Since the silicon content is within the appropriate range, the α-Al phase and the eutectic silicon phase can be in a suitable ratio, so that the wear resistance and strength of the cam bearing seat structure meet the requirements.

[0118] Since Comparative Example 1 does not contain silicon, its wear resistance does not meet the standard and there is a risk of shaft seizure.

[0119] In Comparative Example 2, since the mass fraction of Si is 10%, the strength is greater than 200 MPa, but the wear resistance does not meet the standard and there is a risk of shaft seizure.

[0120] In Comparative Example 3, since the mass fraction of Si is 15%, the wear resistance is less than 1.00, and the wear resistance meets the standard, but the yield strength is less than 200 MPa, and the strength does not meet the standard.

[0121] In summary, by changing the raw material composition of the cam bearing seat structure, the weight of the cam bearing seat structure can be reduced, allowing the upper cover and base of the cam bearing seat structure to be processed from the same material, simplifying the process. Furthermore, the different load-bearing and wear-resistance requirements of the upper cover and base of the cam bearing seat structure can be met simultaneously, eliminating the need for bushings between the upper cover and base of the cam bearing seat structure and the camshaft, thus reducing the use of bushings. Within this Si mass fraction range, good wear resistance is achieved, making bushings possible. Within this Mg mass fraction range, solution treatment and artificial aging can achieve optimal yield strength and elongation. Within this Mn mass fraction range, the material not only achieves good anti-sticking properties but also forms "Chinese character"-shaped Fe-Mn compounds with the Fe incorporated into the alloy, thereby reducing the negative impact of the acicular Fe lattice structure on the matrix structure, which reduces the yield strength and elongation of the material. Within this Ti mass fraction range, the microstructure is refined and a grain size of 7-8 is achieved, thereby achieving good yield strength. Within this Sr mass fraction range, a good modification effect is achieved, thereby improving the yield strength of the material. When the mass fraction of Zr is within this range, the recrystallization temperature of the alloy can be increased, thereby improving the high-temperature strength of the material.

[0122] In the description of this specification, the description with reference to the terms "one embodiment / method", "some embodiments / methods", "example", "specific example" or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment / method or example are included in at least one embodiment / method or example of the present application. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment / method or example. Moreover, the specific features, structures, materials or characteristics described may be combined in an appropriate manner in any one or more embodiments / methods or examples. In addition, those skilled in the art may combine and combine different embodiments / methods or examples described in this specification and the features of different embodiments / methods or examples, unless they are contradictory.

[0123] It should be noted that, in the present application, relational terms such as "first" and "second" are merely used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply the existence of any such actual relationship or order between these entities or operations. Moreover, the terms "comprise", "include" or any other variants thereof are intended to cover non-exclusive inclusion, so that the process, method, article or equipment comprising a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or equipment. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the presence of other identical elements in the process, method, article or equipment comprising the elements. In the present application, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly specified.

[0124] The foregoing is merely a list of specific embodiments of the present application, intended to enable those skilled in the art to understand or implement the present application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application is not limited to the embodiments shown herein, but is intended to conform to the broadest scope consistent with the principles and novel features of the present application.

Claims

1. A cam bearing seat structure, characterized in that: The bearing base and the bearing cover are formed with a camshaft hole for mounting a cam, and the side wall of the camshaft hole has a lubricating oil groove, wherein: Calculated by mass fraction, the raw material composition of the cam bearing seat structure includes: Si: 11.5% to 14.5%; Mg: 0.35% to 0.45%; Mn: 0.35% to 0.50%; Ti: 0.06% to 0.12%; Sr: 0.015% to 0.025%; Zr: 0.01% to 0.1%; the remainder is Al and unavoidable impurities.

2. The cam bearing seat structure according to claim 1, wherein: The metallographic structure of the cam bearing seat structure includes α-Al phase and eutectic silicon phase.

3. The cam bearing seat structure according to claim 1, wherein: The mass ratio of Si to Al is (13-17):

100.

4. The cam bearing seat structure according to claim 1, wherein: The cam bearing seat structure has a bearing load of 0.1 to 100 MPa.

5. A method for processing a cam bearing seat structure according to any one of claims 1 to 4, characterized in that: The following steps are involved: Mixing and melting the raw materials according to their composition to obtain an aluminum alloy melt; The aluminum alloy melt is refined, deslagging, degassing, modifying and cooling to obtain a pretreated melt; Casting the pretreated solution into a mold and demoulding it to obtain a prefabricated part; The prefabricated part is subjected to solution treatment, quenching and aging treatment to obtain a cam bearing seat structure.

6. The method for processing a cam bearing seat structure according to claim 5, wherein: The pretreated melt is molded and demoulded to obtain a preform, wherein the mold is filled with a graphite powder layer, wherein: The particle size of the graphite powder is 800 to 1000 nm; and / or, The thickness of the graphite powder layer is 40 to 50 μm.

7. The method for processing a cam bearing seat structure according to claim 5, wherein: The prefabricated part is subjected to solution treatment, quenching and aging treatment to obtain the cam bearing seat structure: The solution temperature is 500-540°C; and / or, The solution time is 2 to 4 hours; and / or, The aging temperature is 160-180°C; and / or The aging time is 2 to 4 hours.

8. The method for processing a cam bearing seat structure according to claim 5, wherein: The cam bearing seat structure is obtained by subjecting the prefabricated part to solution treatment, quenching, and aging treatment, wherein the quenching treatment method includes water quenching, wherein: The water quenching temperature is 70-90°C; and / or, The water quenching time is 8 to 15 minutes.

9. An engine, characterized in that: A cam bearing seat structure comprising the cam bearing seat structure as claimed in any one of claims 1 to 4, or a cam bearing seat structure manufactured by the processing method of the cam bearing seat structure as claimed in any one of claims 5 to 8.

10. A vehicle, characterized in that Comprising the engine of claim 9.

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