阅读说明：本技术 一种芯壳结构高导热耐磨损复合气门导管及其制作工艺 (Core-shell structure high-heat-conductivity wear-resistant composite valve guide pipe and manufacturing process thereof ) 是由 薛飞 李勇 王宏庆 李�诚 孙玲 于 2021-07-19 设计创作，主要内容包括：本发明公开了一种芯壳结构高导热耐磨损复合气门导管及其制作工艺,本发明涉及汽车零部件粉末冶金技术领域。“芯”为耐磨性较好的铁基合金粉末冶金材料,内孔孔隙含润滑油,与气门接触,表现优异耐磨损自润滑性能。“壳”为高导热紫铜,高效将“芯”的热量传导至缸盖散热,降低了“芯”的实际工作温度,优化了磨损环境,同时紫铜较好的延展性能更加有利于气门导管压入缸盖,成本优势明显,能够满足发动机性能提升需求。(The invention discloses a core-shell structure high-heat-conductivity wear-resistant composite valve guide pipe and a manufacturing process thereof, and relates to the technical field of powder metallurgy of automobile parts. The core is an iron-based alloy powder metallurgy material with better wear resistance, and the inner hole pores contain lubricating oil and are in contact with the valve, so that the valve has excellent wear-resistant self-lubricating performance. The shell is made of red copper with high heat conduction, heat of the core is conducted to the cylinder cover to dissipate heat efficiently, the actual working temperature of the core is reduced, the abrasion environment is optimized, meanwhile, the better extending performance of the red copper is more beneficial to the valve guide to be pressed into the cylinder cover, the cost advantage is obvious, and the requirement for improving the performance of the engine can be met.)

1. The utility model provides a core shell structure high heat conduction stand wear and tear compound valve pipe, includes compound valve pipe, its characterized in that: the composite valve guide pipe is characterized in that a core and a shell are respectively arranged at the inner part and the outer part of the composite valve guide pipe, the core is made of oil-impregnated iron-based alloy powder metallurgy materials, the tolerance of the outer diameter is +/-5 mu m, the shell is made of high-heat-conductivity red copper, the thickness is 8-20 mu m, and the composite valve guide pipe is compounded by adopting an electroplating process;

the manufacturing process of the composite valve guide pipe comprises the following steps:

step S1: selecting core materials, weighing the powder according to a proportion, sieving the powder through a sieving equipment main body, and mixing the powder according to a certain proportion;

step S2: pressing the mixed powder on a forming press to form a green body with a certain shape and strength;

step S3: sintering the pressed and formed green body in a sintering furnace at a high temperature according to a standard material sintering process, wherein the sintering process is different from the conventional conduit sintering, the vacuum oil immersion is carried out after the sintering, the conduit is not immersed in the oil after the sintering process, and the mechanical processing is directly carried out to obtain the core part size, wherein the tolerance of the outer diameter is +/-5 mu m;

step S4: the barrel plating process is adopted for compounding, so that the loading capacity and buffering substances are reasonably arranged in order to prevent the valve guide pipes from being damaged due to mutual collision in the barrel plating process;

step S5: sealing the inner hole of the conduit before barrel plating, removing oil by barrel plating to ensure the binding force of a plating layer, controlling a plating solution and a barrel plating process, and controlling the thickness of the plating layer to be 15 +/-5 mu m;

step S6: and after barrel plating, performing surface passivation treatment and performing vacuum oil immersion.

2. The high-thermal-conductivity wear-resistant composite valve guide pipe with the core-shell structure as claimed in claim 1, wherein: and plating copper on the excircle of the composite valve guide pipe, sealing the inner hole, and obtaining the size of the copper-plated composite valve guide pipe as the size of a finished product.

3. The high-thermal-conductivity wear-resistant composite valve guide pipe with the core-shell structure as claimed in claim 1, wherein: the sieving in the step S1 specifically comprises the following steps:

powder enters the interior of a sieving equipment main body from a feeding cylinder (1), at the moment, a driving motor (2) is started, the driving end of the driving motor (2) is connected with a driving wheel (3), the driving wheel (3) rotates, the driving wheel (3) and a driven wheel (7) are transmitted through a transmission belt (6), the driven wheel (7) rotates along with the driving wheel (3), the driven wheel (7) is rotatably connected with one end of a connecting rod (8), the other end of the connecting rod (8) is rotatably connected with a sieve plate (11), so that the sieve plate (11) is driven to displace by the displacement of the connecting rod (8), the surface of the sieve plate (11) is limited through a spring connecting piece (13), powder falling on the surface of the sieve plate (11) is shaken and discharged, and dust meeting the requirement of particle size enters a discharging plate (15) from the sieve plate (11), and taking materials from the discharge port (9), pressing the powder from the compression roller (14) which does not meet the requirement, and discharging the powder which does not meet the standard from the side discharge port (12) along the sieve plate (11).

4. The high-thermal-conductivity wear-resistant composite valve guide pipe with the core-shell structure as claimed in claim 1, wherein: and after the electroplating passivation is finished, the composite valve guide pipe is subjected to vacuum oil immersion.

5. The high-thermal-conductivity wear-resistant composite valve guide pipe with the core-shell structure as claimed in claim 1, wherein: the core is made of one of GJF170, GJF170M, ZC30W or WQ 98T.

6. A manufacturing process of a core-shell structure high-heat-conductivity wear-resistant composite valve guide pipe is characterized by comprising the following steps of: comprises the following steps:

weighing the powder in proportion, sieving the powder by a 60-100 mesh sieve to prevent the powder from agglomerating and mixing foreign matters, and stirring and mixing the sieved powder on a V-shaped mixer for 20-50 minutes; and then, pressing the mixed powder on a forming press to form a green body with a certain shape and strength, sintering the formed green body at a high temperature in a sintering furnace, roughly grinding the outer circle of the guide pipe by using a grinding machine after sintering, processing the length and inner and outer chamfers by using a numerical control lathe, finely grinding the outer circle by using a centerless grinding machine to obtain a composite valve guide pipe core, controlling the tolerance of the outer diameter of the core part to be +/-5 mu m, sealing an inner hole before plating, controlling the transferring amount, a buffer substance, a plating solution and an electroplating process, controlling the thickness of a shell to be 15 +/-5 mu m, passivating after electroplating, and finally soaking in oil for packaging.

Technical Field

The invention relates to the technical field of powder metallurgy of automobile parts, in particular to a core-shell structure high-heat-conductivity wear-resistant composite valve guide pipe and a manufacturing process thereof.

Background

Along with the increasing performance of the engine and the implementation of national six standards for pollutant emission, the temperature of the exhaust side of the engine is higher and higher, heat needs to be transferred to a cylinder cover through a valve guide pipe, and the valve guide pipe plays a role in positioning and guiding and is in contact with a valve, so that the valve guide pipe not only needs to have excellent wear resistance, but also needs to have high heat conductivity in order to meet the development requirements of modern engines. Although the normal-temperature wear resistance of the cast copper guide pipe is weaker than that of the iron-based alloy powder metallurgy valve guide pipe, the cast copper guide pipe has higher heat conduction performance, so that the relative working temperature under the high-temperature working condition is lower than that of the iron-based alloy powder metallurgy valve guide pipe, the high-temperature wear resistance is superior to that of the iron-based alloy powder metallurgy valve guide pipe, and the cost is higher. Compared with the traditional iron-based alloy powder metallurgy valve guide, the copper-infiltrated iron-based alloy powder metallurgy valve guide has the advantages that the heat conduction performance is improved, the actual abrasion temperature is reduced, the matrix softening caused by high copper can be offset, the more excellent abrasion resistance is realized, and the cost is relatively high. The patent provides a core-shell structure high heat conduction wear-resistant composite valve guide and manufacturing process, compares in above two kinds of pipes, and the cost advantage is obvious, "the core" is the better iron-based alloy powder metallurgy material of wearability, and the hole contains lubricating oil, contacts with the valve, shows excellent stand wear and tear self-lubricating property, "the shell" is high heat conduction red copper, and the high efficiency is with the heat conduction of "the core" to the cylinder cap heat dissipation, has reduced the actual operating temperature of "the core", has optimized the wearing and tearing environment.

Disclosure of Invention

Aiming at the defects of the prior art, the invention provides a core-shell structure high-heat-conductivity wear-resistant composite valve guide pipe and a manufacturing process thereof, and solves the problems.

In order to achieve the purpose, the invention is realized by the following technical scheme: a core-shell structure high-heat-conductivity wear-resistant composite valve guide pipe comprises a composite valve guide pipe, wherein a core and a shell are respectively arranged at the inner part and the outer part of the composite valve guide pipe, the core is made of oil-impregnated iron-based alloy powder metallurgy materials, the tolerance of the outer diameter is +/-5 mu m, the shell is made of high-heat-conductivity red copper, the thickness is 8-20 mu m, and the core and the shell are compounded by adopting an electroplating process;

the manufacturing process of the composite valve guide pipe comprises the following steps:

step S1: selecting core materials, weighing the powder according to a proportion, sieving the powder through a sieving equipment main body, and mixing the powder according to a certain proportion;

step S2: pressing the mixed powder on a forming press to form a green body with a certain shape and strength;

step S3: sintering the pressed and formed green body in a sintering furnace at a high temperature according to a standard material sintering process, wherein the sintering process is different from the conventional conduit sintering, the vacuum oil immersion is carried out after the sintering, the conduit is not immersed in the oil after the sintering process, and the mechanical processing is directly carried out to obtain the core part size, wherein the tolerance of the outer diameter is +/-5 mu m;

step S4: the barrel plating process is adopted for compounding, so that the loading capacity and buffering substances are reasonably arranged in order to prevent the valve guide pipes from being damaged due to mutual collision in the barrel plating process;

step S5: sealing the inner hole of the conduit before barrel plating, removing oil by barrel plating to ensure the binding force of a plating layer, controlling a plating solution and a barrel plating process, and controlling the thickness of the plating layer to be 15 +/-5 mu m;

step S6: and after barrel plating, performing surface passivation treatment and performing vacuum oil immersion.

As a further scheme of the invention: and plating copper on the excircle of the composite valve guide pipe, sealing the inner hole, and obtaining the size of the copper-plated composite valve guide pipe as the size of a finished product.

As a further scheme of the invention: the sieving in the step S1 comprises a sieving equipment main body, wherein the sieving equipment main body comprises an installation panel, a feeding cylinder is fixedly arranged on the surface of the upper side of the installation panel, a driving motor is fixedly arranged on the surface of the upper side of the installation panel and positioned on one side of the feeding cylinder, a driving wheel is fixedly arranged on the driving end of the driving motor, a rotating fixing seat is fixedly arranged on the surface of the bottom of the installation panel, a driven wheel is rotatably arranged in the rotating fixing seat, a driving belt is jointly arranged on the surfaces of the driving wheel and the driven wheel, the driven wheel is connected with the driving wheel through the transmission of the driving belt, a sieving cabin is arranged on the surface of the bottom of the installation panel, a discharging port is arranged on one side of the bottom of the sieving cabin, a side discharging port is arranged on the side wall of the sieving cabin, which is far away from the discharging port, and spring connecting pieces are fixedly arranged at two ends of the top of the sieving cabin, a sieve plate is arranged in the screening cabin through a spring connecting piece, a press roller is rotatably arranged in the screening cabin and on the upper side of the sieve plate, a blanking plate is arranged in the screening cabin and on the lower side of the sieve plate, the inclination direction of the blanking plate is opposite to that of the sieve plate, the surface of the driven wheel is rotatably connected with one end of a connecting rod, and the other end of the connecting rod is rotatably connected with the side wall of the sieve plate;

get into the inside of equipment main part that sieves from feed cylinder department earlier with the powder, driving motor starts this moment, link to each other between driving motor's drive end and the action wheel, the action wheel rotates, the action wheel with follow between the driving wheel through the drive belt transmission, follow the action wheel and rotate, it is connected to rotate between the one end of driving wheel and connecting rod, the other end and the sieve station of connecting rod rotate to be connected, the displacement of connecting rod just drives the sieve and carries out the displacement like this, the surface of sieve limits through spring coupling spare, the unloading is rocked to the powder that will fall on the surface of sieve, the dust that accords with the granule size requirement enters into on the flitch from the sieve, get the material from discharge gate department, the follow compression roller that is not conform to the requirement carries out the dust, still powder that is not up to standard is discharged from the side discharge gate along the sieve.

As a further scheme of the invention: the arrangement position of the feeding cylinder corresponds to the highest inclined position of the sieve plate.

As a further scheme of the invention: and after the electroplating passivation is finished, the composite valve guide pipe is subjected to vacuum oil immersion.

As a further scheme of the invention: the core is made of one of GJF170, GJF170M, ZC30W or WQ 98T.

A manufacturing process of a core-shell structure high-heat-conductivity wear-resistant composite valve guide pipe comprises the following steps:

weighing the powder in proportion, sieving the powder by a 60-100 mesh sieve to prevent the powder from agglomerating and mixing foreign matters, and stirring and mixing the sieved powder on a V-shaped mixer for 20-50 minutes; and then, pressing the mixed powder on a forming press to form a green body with a certain shape and strength, sintering the formed green body at a high temperature in a sintering furnace, roughly grinding the outer circle of the guide pipe by using a grinding machine after sintering, processing the length and inner and outer chamfers by using a numerical control lathe, finely grinding the outer circle by using a centerless grinding machine to obtain a composite valve guide pipe core, controlling the tolerance of the outer diameter of the core part to be +/-5 mu m, sealing an inner hole before plating, controlling the transferring amount, a buffer substance, a plating solution and an electroplating process, controlling the thickness of a shell to be 15 +/-5 mu m, passivating after electroplating, and finally soaking in oil for packaging.

Advantageous effects

The invention provides a core-shell structure high-heat-conductivity wear-resistant composite valve guide pipe and a manufacturing process thereof.

Compared with the prior art, the method has the following beneficial effects:

1. a core-shell structured high-heat-conductivity wear-resistant composite valve guide pipe and a manufacturing process thereof are disclosed, wherein a core is made of iron-based alloy powder metallurgy material with better wear resistance, and pores of an inner hole contain lubricating oil and are in contact with a valve, so that the valve guide pipe has excellent wear-resistant and self-lubricating properties. The shell is made of red copper with high heat conduction, heat of the core is conducted to the cylinder cover to dissipate heat efficiently, the actual working temperature of the core is reduced, the abrasion environment is optimized, meanwhile, the better extending performance of the red copper is more beneficial to the valve guide to be pressed into the cylinder cover, the cost advantage is obvious, and the requirement for improving the performance of the engine can be met.

2. A core-shell structured high-heat-conductivity wear-resistant composite valve guide pipe and a manufacturing process thereof are disclosed, powder firstly enters the interior of a sieving equipment main body from a feeding cylinder, a driving motor is started at the moment, a driving end of the driving motor is connected with a driving wheel, the driving wheel rotates, the driving wheel and a driven wheel are driven by a driving belt, the driven wheel rotates along with the driving wheel, the driven wheel is connected with one end of a connecting rod in a rotating way, the other end of the connecting rod is connected with a sieve plate station in a rotating way, so that the sieve plate is driven to move by the displacement of the connecting rod, the surface of the sieve plate is limited by a spring connecting piece, the powder falling on the surface of the sieve plate is shaken and fed, the dust meeting the requirement of particle size enters a feeding plate from the sieve plate, the powder is pressed from a compression roller which does not meet the requirement from a discharge port, and the powder which still does not meet the requirement is discharged from a side discharge port along the sieve plate, make its screening that can be better when sieving to the powder that meets the requirements is discharged from one side, and the great graininess is sieved again after the dust is pressed, and the continuation that meets the requirements is discharged, and the independent discharge that does not meet the requirements conveniently selects the powder that meets the requirements, and simple structure is effective, is convenient for maintain the use.

Drawings

FIG. 1 is a schematic view of a composite valve guide of the present invention;

FIG. 2 is a thickness diagram of a composite valve guide mid-shell of the present invention;

FIG. 3 is a schematic view of the main structure of the sieving apparatus of the present invention;

fig. 4 is a schematic view of the internal structure of the sieving device main body of the present invention.

In the figure: 1. a feeding cylinder; 2. a drive motor; 3. a driving wheel; 4. installing a panel; 5. rotating the fixed seat; 6. a transmission belt; 7. a driven wheel; 8. a connecting rod; 9. a discharge port; 10. screening the cabin; 11. a sieve plate; 12. a side discharge port; 13. a spring connector; 14. a compression roller; 15. and discharging the material plate.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Referring to fig. 1-4, the present invention provides a technical solution: a core-shell structure high-heat-conductivity wear-resistant composite valve guide pipe comprises a composite valve guide pipe, wherein a core and a shell are respectively arranged at the inner part and the outer part of the composite valve guide pipe, the core is made of oil-impregnated iron-based alloy powder metallurgy materials, the tolerance of the outer diameter is +/-5 mu m, the shell is made of high-heat-conductivity red copper, the thickness is 8-20 mu m, and the core and the shell are compounded by adopting an electroplating process;

the manufacturing process of the composite valve guide pipe comprises the following steps:

step S1: selecting core materials, weighing the powder according to a proportion, sieving the powder through a sieving equipment main body, and mixing the powder according to a certain proportion;

step S2: pressing the mixed powder on a forming press to form a green body with a certain shape and strength;

step S3: sintering the pressed and formed green body in a sintering furnace at a high temperature according to a standard material sintering process, wherein the sintering process is different from the conventional conduit sintering, the vacuum oil immersion is carried out after the sintering, the conduit is not immersed in the oil after the sintering process, and the mechanical processing is directly carried out to obtain the core part size, wherein the tolerance of the outer diameter is +/-5 mu m;

step S4: the barrel plating process is adopted for compounding, so that the loading capacity and buffering substances are reasonably arranged in order to prevent the valve guide pipes from being damaged due to mutual collision in the barrel plating process;

step S5: sealing the inner hole of the conduit before barrel plating, removing oil by barrel plating to ensure the binding force of a plating layer, controlling a plating solution and a barrel plating process, and controlling the thickness of the plating layer to be 15 +/-5 mu m;

step S6: and after barrel plating, performing surface passivation treatment and performing vacuum oil immersion.

And plating copper on the excircle of the composite valve guide pipe, sealing the inner hole, and obtaining the size of the copper-plated composite valve guide pipe as the size of a finished product.

And after the electroplating passivation is finished, the composite valve guide pipe is subjected to vacuum oil immersion.

The sieving in the step S1 comprises a sieving equipment main body, wherein the sieving equipment main body comprises an installation panel 4, a feeding cylinder 1 is fixedly arranged on the surface of the upper side of the installation panel 4, a driving motor 2 is fixedly arranged on the surface of the upper side of the installation panel 4 and on one side of the feeding cylinder 1, a driving wheel 3 is fixedly arranged on the driving end of the driving motor 2, a rotating fixing seat 5 is fixedly arranged on the surface of the bottom of the installation panel 4, a driven wheel 7 is rotatably arranged in the rotating fixing seat 5, a driving belt 6 is jointly arranged on the surfaces of the driving wheel 3 and the driven wheel 7, the driven wheel 7 is in transmission connection through the driving belt 6 on the driving wheel 3, a sieving cabin 10 is arranged on the surface of the bottom of the installation panel 4, a discharging port 9 is arranged on one side of the bottom of the sieving cabin 10, a side discharging port 12 is arranged on the side wall of the sieving cabin 10, which deviates from the discharging port 9, the fixed spring coupling 13 that is provided with in inside top both ends of screening cabin 10, the inside of screening cabin 10 is provided with sieve 11 through spring coupling 13, the inside of screening cabin 10 and the upside that is located sieve 11 rotate and are provided with compression roller 14, the inside of screening cabin 10 and the downside that is located sieve 11 are provided with down flitch 15, and flitch 15's incline direction is opposite with sieve 11's incline direction down, from the surperficial one end rotation with connecting rod 8 of driving wheel 7 and be connected, the other end of connecting rod 8 rotates on the lateral wall with sieve 11 and links to each other, the highest position department of slope of feeding section of thick bamboo 1 that sets up position and sieve 11 is corresponding.

When in use, powder firstly enters the sieving equipment body from the feeding cylinder 1, the driving motor 2 is started, the driving end of the driving motor 2 is connected with the driving wheel 3, the driving wheel 3 rotates, the driving wheel 3 and the driven wheel 7 are transmitted through the transmission belt 6, the driven wheel 7 rotates along with the driving wheel 3, the driven wheel 7 is rotatably connected with one end of the connecting rod 8, the other end of the connecting rod 8 is rotatably connected with the sieve plate 11, the displacement of connecting rod 8 just drives sieve 11 like this and carries out the displacement, and the surface of sieve 11 is restricted through spring coupling 13, will fall on the sieve 11 powder on the surface rock the unloading, and the dust that accords with the granule size requirement enters into on unloading board 15 from sieve 11, gets the material from discharge gate 9, and the follow compression roller 14 that does not accord with the requirement carries out the dust pressing, and the powder that still does not reach standard is along sieve 11 from side discharge gate 12 discharges.

The material of the core is one of GJF170, GJF170M, ZC30W or WQ98T, but is not limited to the material.

The GJF170 comprises the following materials in percentage by weight: 1-2%, Cu: 1-2%, Ni: 2-4%, Mn: 0-3%, Fe: the balance of the percentage content is left.

The GJF170M comprises the following materials in percentage by weight: 1.5-3%, Cu: 1.5-2.5%, Ni: 3-4%, Mg: 0-4%, Fe: the balance of the percentage content is left.

The material proportion of ZC30W is C: 0.9-1.5%, Mo: 0.5-1%, Ca: 1-1.5%, Cu: 3-6%, S: 0.3-2%, Mn: 0-2%, Fe: the balance of the percentage content is left.

The WQ98T comprises the following materials in percentage by weight: 1.8-2%, S: 0.3-0.5%, Cu: 15-23.5%, Mo: 2-3%, Cr: 1-1.5%, Mg: 0-4%, Fe: the balance of the percentage content is left.

A manufacturing process of a core-shell structure high-heat-conductivity wear-resistant composite valve guide pipe comprises the following steps:

weighing the powder in proportion, sieving the powder by a 60-100 mesh sieve to prevent the powder from agglomerating and mixing foreign matters, and stirring and mixing the sieved powder on a V-shaped mixer for 20-50 minutes; and then, pressing the mixed powder on a forming press to form a green body with a certain shape and strength, sintering the formed green body at a high temperature in a sintering furnace, roughly grinding the outer circle of the guide pipe by using a grinding machine after sintering, processing the length and inner and outer chamfers by using a numerical control lathe, finely grinding the outer circle by using a centerless grinding machine to obtain a composite valve guide pipe core, controlling the tolerance of the outer diameter of the core part to be +/-5 mu m, sealing an inner hole before plating, controlling the transferring amount, a buffer substance, a plating solution and an electroplating process, controlling the thickness of a shell to be 15 +/-5 mu m, passivating after electroplating, and finally soaking in oil for packaging.

Example 1

In the embodiment, a material ZC30W is selected, and a valve guide drawing is selected to manufacture a finished product.

Example 2

In this embodiment, a material GJF170 is selected, and a valve guide drawing is selected to manufacture a finished product.

Example 3

In this embodiment, a material WQ98T is selected, and a valve guide drawing is selected to manufacture a finished product.

Comparative example 1

The comparison example adopts a core-shell structure high-heat-conductivity wear-resistant composite valve guide and a manufacturing process, adopts GJF170M material to manufacture a core and a shell with the thickness of 15 mu m, selects a valve guide drawing, and performs oil immersion treatment on an inner hole to manufacture a finished product.

Comparative example 2

The comparison example adopts a core-shell structure high-heat-conductivity wear-resistant composite valve guide and a manufacturing process, adopts GJF170 material to manufacture a core and a shell, the thickness of the core and the shell is 15 mu m, selects a valve guide drawing, and performs oil immersion treatment on an inner hole to manufacture a finished product.

Comparative example 3

The comparative example adopts a core-shell structure high-heat-conductivity wear-resistant composite valve guide pipe and a manufacturing process, adopts WQ98T material to manufacture a core and a shell, the thickness of the shell is 15 mu m, selects a valve guide pipe drawing, and performs oil immersion treatment on an inner sealing hole to manufacture a finished product.

Comparative example 4

The comparison example adopts a core-shell structure high-heat-conductivity wear-resistant composite valve guide and a manufacturing process, adopts GJF170 material to manufacture a core and a shell, the thickness of the core and the shell is 5 mu m, selects a valve guide drawing, and performs oil immersion treatment on an inner hole to manufacture a finished product.

Comparative example 5

The comparison example adopts a core-shell structure high-heat-conductivity wear-resistant composite valve guide and a manufacturing process, adopts GJF170 material to manufacture a core and a shell, the thickness of the core and the shell is 35 mu m, selects a valve guide drawing, and performs oil immersion treatment on an inner sealing hole to manufacture a finished product.

Comparative example 6

The comparative example adopts a core-shell structure high-heat-conductivity wear-resistant composite valve guide and a manufacturing process, adopts ZC30W material to manufacture a core and a shell with the thickness of 15 mu m, selects a valve guide drawing, and manufactures a finished product by sealing an inner hole without oil immersion treatment.

The above valve guides were subjected to press fitting experiments using a universal testing machine, and the experimental results are shown in table 1.

TABLE 1

The abrasion resistance test was carried out on the valve guide tubes by using a valve guide tube abrasion tester of this company under the test conditions of 250 ℃ temperature, 2000rpm rotation, 10 hours of test time, valve guide tube abrasion tester as test equipment, and the test results are shown in Table 2 below.

TABLE 2

As can be seen from table 1, the core-shell structured wear-resistant composite valve guide tube obtained by the present invention is easier to press-fit and less prone to fall off, and exhibits better press-fit performance, compared to the conventional powder metallurgy valve guide tube. As can be seen from the examples 1-3 and the comparative examples 1-3 in the table 2, the designed high-heat-conductivity wear-resistant composite valve guide with the core-shell structure has more excellent wear resistance, the high wear-resistance self-lubricating property of the core part and the high heat-conductivity property of the shell are cooperatively exerted. As can be seen from table 2, example 2, comparative examples 2, 4 and 5, the thickness of the "shell" should not be too thin, otherwise high thermal conductivity is not exhibited, and resources are wasted if it is too thick. As can be seen from Table 2, example 2 and comparative examples 2 and 6, the "core" part of the design needs to be soaked with oil to exert self-lubricating performance. A core-shell structure high-heat-conductivity wear-resistant composite valve guide and a manufacturing process thereof are disclosed, wherein the core is an iron-based alloy powder metallurgy material with better wear resistance, and pores of an inner hole contain lubricating oil and are in contact with a valve, so that the valve guide has excellent wear-resistant self-lubricating performance. The shell is made of red copper with high heat conduction, heat of the core is conducted to the cylinder cover to dissipate heat efficiently, the actual working temperature of the core is reduced, the abrasion environment is optimized, meanwhile, the better extending performance of the red copper is more beneficial to the valve guide to be pressed into the cylinder cover, the cost advantage is obvious, and the requirement for improving the performance of the engine can be met.

In the description of the present invention, it is to be understood that the terms "upper", "lower", "left", "right", and the like, indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, are only for convenience in describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation and a specific orientation configuration and operation, and thus, should not be construed as limiting the present invention. Furthermore, "first" and "second" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless otherwise specified.