Method for manufacturing a brake disc for a vehicle

Abstract

The application relates to a preparation method of an automobile brake disc. An annular disc body is arranged in a first part of a mold cavity of a mold, preheating is performed to 200 DEG C-250 DEG C after the mold is closed, a cooling device is started, the air flow pressure entering a melt furnace is controlled to be 0.05MPa-0.15MPa, the melt of a ceramic reinforced aluminum matrix composite material is compressed to enter the mold cavity through a riser pipe, pressure maintaining is performed for 10s-25s, pressure releasing is performed, cooling is performed, demolding is performed, and machining is performed, so that the automobile brake disc is obtained. The method can obtain the automobile brake disc with high compactness, perfect appearance without cracks and good interface consistency.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of brake disc preparation, in particular to a preparation method of an automobile brake disc. BACKGROUND

[0002] Lightweight is one of the most effective means to achieve energy saving and consumption reduction of automobiles and other transportation vehicles. Using high-performance light metal materials to replace steel materials in key moving parts such as engines and brake discs of transportation equipment can not only reduce the weight of the whole vehicle and the momentum of high-speed moving parts of the transportation equipment, but also significantly improve the power performance of the transportation equipment while reducing energy consumption.

[0003] Ceramic reinforced aluminum matrix composite has low density, high specific strength and specific stiffness, high thermal conductivity, and excellent wear resistance and corrosion resistance, and has broad application prospects in the field of lightweight structural parts. Specifically applied to brake discs, the disc body needs to have high temperature resistance and wear resistance, and the disc cap needs to have relatively high mechanical properties. Therefore, the disc body adopts high-volume-fraction ceramic reinforced aluminum matrix composite, and the disc cap adopts low-volume-fraction ceramic reinforced aluminum matrix composite to meet the performance requirements of each other. However, when the above brake disc is prepared by using the traditional powder metallurgy process, the two powder materials are easy to penetrate each other during powder filling and pressing, resulting in an elliptical or even completely irregular interface between the disc body and the disc cap. In addition, considering that the formability of the ceramic reinforced aluminum matrix composite is poor due to the addition of ceramic reinforcing phase, a simple green body such as a ring-shaped or columnar green body is usually first pressed, then sintered, and then the overall structure of the brake disc such as a disc cap containing a goose neck structure is formed by forging, and finally the final product is machined. However, the flow of materials during the forging process is not easy to control, and cracks are easy to appear on the outside of the disc cap. SUMMARY

[0004] Therefore, it is necessary to provide a preparation method of an automobile brake disc, which can ensure that the interface between the disc cap and the disc body remains consistent even if the materials of the disc cap and the disc body are different, and the prepared brake disc has good compactness and no cracks, and meets the braking requirements.

[0005] A preparation method of an automobile brake disc, the automobile brake disc comprising a ring-shaped disc body and a disc cap, the disc cap comprising an end portion, a sidewall extending axially along the end portion, and a connecting portion extending radially along the sidewall, the preparation method of the automobile brake disc comprising the following steps:

[0006] providing the ring-shaped disc body;

[0007] The mold comprises a coaxial upper mold, a lower mold and a female mold. After the mold is closed, the upper mold and the lower mold enclose the female mold to form a mold cavity. The mold cavity comprises a first part and a second part which are in communication with each other. The first part is matched with the annular disc body, and the second part is matched with the disc cap to be formed. The upper mold is provided with a cooling device in the part for forming the disc cap.

[0008] The melt furnace comprises a furnace body and a riser tube. One end of the riser tube is located in the furnace body, and the other end penetrates through the center of the lower mold and communicates with the mold cavity. The furnace body is filled with a ceramic reinforced aluminum matrix composite melt.

[0009] The annular disc body is placed in the first part of the mold cavity, and after the mold is closed, it is preheated to 200-250°C. The cooling device is started, the air pressure flowing into the furnace body is controlled to be 0.05-0.15 MPa, the ceramic reinforced aluminum matrix composite melt is compressed to enter the mold cavity through the riser tube, the pressure is maintained for 10-25 s, then the pressure is released, cooled, demolded, and machined to obtain an automobile brake disc.

[0010] In one embodiment, the diameter of the riser tube at the communication part with the mold cavity is 50-70 mm.

[0011] In one embodiment, the thickness of the part of the upper mold for forming the end portion is 20-30 mm, and the thickness of the part of the upper mold for forming the side wall is 15-25 mm.

[0012] In one embodiment, the annular disc body comprises an outer ring part and an inner ring part. The outer ring part is used for friction braking with brake pads, and the inner ring part is used for engaging with the disc cap. The thickness of the inner ring part is less than that of the outer ring part.

[0013] In one embodiment, the inner ring part is uniformly distributed with a plurality of axial through holes in the circumferential direction. The diameter of each axial through hole is 8-16 mm.

[0014] In one embodiment, the ceramic reinforced aluminum matrix composite melt is composed of 10-20% ceramic reinforced particles and the balance of aluminum alloy. The annular disc body is prepared from 35-55% ceramic reinforced aluminum matrix composite material and the balance of aluminum alloy. The aluminum alloy is selected from at least one of two series aluminum alloy, four series aluminum alloy and six series aluminum alloy.

[0015] In one embodiment, the temperature of the ceramic reinforced aluminum matrix composite melt is 700-740°C.

[0016] In one embodiment, the temperature of the cooling is below 100°C.

[0017] In one embodiment, the height of the side wall of the cap is 10mm to 35mm.

[0018] In one embodiment, the height of the side wall of the cap is greater than 35mm, and the step of demolding and machining further comprises a step of forging densification.

[0019] The method for manufacturing the automobile brake disc, by controlling the air pressure, introduces the melt of the ceramic reinforced aluminum matrix composite material into the mold cavity in which the annular disc body is placed, under the action of the cooling device, the melt gradually solidifies from the end contacting the disc body to the end far away from the disc body, by controlling the holding time, on the one hand, the melt is ensured to fill the entire mold cavity and solidify completely, on the other hand, the shrinkage hole generated in the casting process can be effectively reduced, and the compactness of the product is improved.

[0020] In addition, since the annular disc body is a finished product, the edge is relatively stable, and the melt solidifies after contacting the edge, so that the edge is not affected, thereby ensuring the consistency of the interface.

[0021] The automobile brake disc manufactured by the above method has no crack in appearance and meets the braking performance required by the existing automobile brake disc. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 The connection structure of the mold and the melt furnace is a schematic view of an embodiment. DETAILED DESCRIPTION

[0023] In order to facilitate the understanding of the present application, the present application will be described more fully below, and the preferred embodiments of the present application will be given. However, the present application can be realized in many different forms, and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present application more thorough and comprehensive.

[0024] It should be noted that when an element is referred to as "provided" on another element, it can be directly on the other element or there can be a middle element. When an element is considered to be "connected" to another element, it can be directly connected to the other element, or a middle element can exist at the same time.

[0025] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present application belongs. The terms used in the specification of the present application herein are only for the purpose of describing the specific embodiments and are not intended to limit the present application. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0026] The method for manufacturing the automobile brake disc in an embodiment comprises the following steps S110-S130:

[0027] S110, providing a ring-shaped disc body.

[0028] The ring-shaped disc body comprises an outer ring portion and an inner ring portion, and the thickness of the inner ring portion is less than that of the outer ring portion. The outer ring portion is used for friction braking with brake pads, and the inner ring portion is used for engaging with a disc cap.

[0029] It can be understood that the inner ring portion can be a continuous inner ring or an inner ring composed of a plurality of protrusions uniformly spaced in the circumferential direction and extending in the radial direction.

[0030] In order to meet the friction braking requirement, the ring-shaped disc body is made of 35-55% ceramic reinforced particles and the balance of aluminum alloy. The aluminum alloy is selected from at least one of two series aluminum alloy, four series aluminum alloy and six series aluminum alloy.

[0031] It should be noted that the ring-shaped disc body of the present application can be made of the above-mentioned materials by powder metallurgy process, or can be made by infiltration process, as long as it can meet the requirement of friction braking.

[0032] Further, the inner ring portion is uniformly distributed with a plurality of axial through holes in the circumferential direction, and the diameter of each axial through hole is 8-16mm. It can be understood that if the inner ring portion is an inner ring composed of a plurality of protrusions uniformly spaced in the circumferential direction and extending in the radial direction, the above-mentioned axial through holes are arranged one by one on each protrusion.

[0033] By arranging the axial through holes, the subsequent ceramic reinforced aluminum matrix composite melt flows into these through holes and solidifies, and the solidified melt completely wraps the inner ring portion of the disc body, which can effectively improve the connection strength of the disc body and the disc cap.

[0034] S120, providing a mold 10 and a melt furnace 20 as shown in Figure 1

[0035] The mold 10 comprises an upper mold 12, a lower mold 14 and a female mold 16 arranged coaxially; after the mold is closed, the upper mold 12 and the lower mold 14 form a mold cavity in the female mold 16. The mold cavity comprises a first part 102 and a second part 104 which are in communication with each other, wherein the first part 102 is matched with the ring-shaped disc body, and the second part 104 is matched with the disc cap to be formed.

[0036] Further, the part of the upper mold 12 for forming the disc cap is provided with a cooling device 18. Further, the cooling device 18 is a circulating cooling water pipe.

[0037] ​In the embodiment, the cap includes an end portion, a sidewall extending axially along the end portion, and a connecting portion extending radially along the sidewall. The upper mold 12 is used to form a portion of the end portion with a thickness of 20-30 mm. The upper mold 12 is used to form a portion of the sidewall with a thickness of 15-25 mm.

[0038] By providing the cooling device 18 in the portion of the upper mold 12 used to form the cap, the temperature in the mold cavity can be gradually reduced.

[0039] Further, the melt furnace 20 includes a furnace body 22 and a riser tube 24, wherein one end of the riser tube 24 is located in the furnace body 22 and the other end of the riser tube 24 communicates with the mold cavity through the center of the lower mold 14.

[0040] Further, the top of the furnace body 22 is provided with an air inlet 222 and a pressure relief port 224. During casting, the pressure relief port 224 is closed, the air flow from the air inlet 222 into the furnace body 22 is controlled, and the melt is compressed to pass through the riser tube 24 into the mold cavity. After the casting is completed, the air inlet 222 is closed and the pressure relief port 224 is opened for pressure relief.

[0041] In the embodiment, the furnace body 22 is filled with a ceramic reinforced aluminum matrix composite melt at a temperature of 700-740°C. The ceramic reinforced aluminum matrix composite melt is composed of 10-20% ceramic reinforced particles and the balance of aluminum alloy. The aluminum alloy is selected from at least one of two series aluminum alloy, four series aluminum alloy and six series aluminum alloy.

[0042] The ceramic reinforced aluminum matrix composite melt with the above special composition can meet the performance requirements of the cap structure of the brake disc and facilitate the machining of the excess solidified melt, such as the solidified melt at the center hole position of the end portion of the cap.

[0043] In the embodiment, the diameter of the riser tube 24 at the position communicating with the mold cavity is 50-70 mm.

[0044] S130, place the above-mentioned annular disc body in the first portion 102 of the mold cavity, preheat to 200-250°C after closing the mold, start the cooling device 18, control the air flow pressure into the furnace body 22 to be 0.05-0.15 MPa, compress the ceramic reinforced aluminum matrix composite melt to pass through the riser tube into the mold cavity, relieve pressure after 10-25 s, cool, demold, and machine to obtain the automobile brake disc.

[0045] The air flow is inert gas flow, such as argon, nitrogen, etc., to prevent the melt from being oxidized to affect the combination with the disc body.

[0046] The annular disc body is placed in the first part of the mold cavity, preheated to 200-250 DEG C, and then the cooling device is started while introducing high-temperature melt, which can effectively remove the water vapor adsorbed on the surface of the mold, avoid the generation of pores on the surface of the workpiece during casting, and avoid the direct contact of high-temperature melt with the cooling disc body and the mold wall, thereby avoiding the generation of cracks.

[0047] By controlling the gas flow pressure to be 0.05-0.15 MPa and the pressure maintaining time to be 10-25 s, the melt can be ensured to fill the entire mold cavity and solidify completely, the shrinkage hole generated during casting can be effectively reduced, the product density can be improved, and thus the subsequent machining to remove the excess solidified melt can be performed without the need for further forging densification.

[0048] Further, the cooling temperature is below 100 DEG C. The demolding after cooling can effectively avoid the deformation of the disc body material and the disc cap material due to the inconsistent thermal expansion coefficients.

[0049] The above method can be used to prepare an automobile brake disc with a disc cap side wall height of 10-35 mm, without the need for forging densification, and can obtain an automobile brake disc with high density, no cracks, and meeting the braking requirements.

[0050] If the disc cap side wall height exceeds 35 mm, the forging densification needs to be performed after demolding and before machining, so as to further improve the density of the brake disc.

[0051] The preparation method of the above automobile brake disc can control the temperature of the melt to be 700-740 DEG C, the thickness of the part of the upper mold 12 used for forming the end portion to be 20-30 mm, the thickness of the part of the upper mold 12 used for forming the side wall to be 15-25 mm, the pipe diameter of the riser pipe 24 communicated with the mold cavity to be 50-70 mm, the gas flow pressure introduced into the melt furnace 20 to be 0.05-0.15 MPa, and the pressure maintaining time to be 10-25 s, so that the melt can just fill the entire mold cavity and solidify completely, the shrinkage hole generated during casting can be effectively reduced, and the product density can be improved.

[0052] The following is a specific embodiment.

[0053] Embodiment 1

[0054] An automobile brake disc with a disc cap side wall height of 35 mm is prepared by using the steps of steps S110-S130, the temperature of the melt is controlled to be 700 DEG C, the thickness of the part of the upper mold 12 used for forming the end portion is controlled to be 20 mm, the thickness of the part of the upper mold 12 used for forming the side wall is controlled to be 15 mm, the pipe diameter of the riser pipe 24 communicated with the mold cavity is controlled to be 50 mm, the gas flow pressure introduced into the melt furnace 20 is controlled to be 0.05 MPa, and the pressure maintaining time is controlled to be 10 s, so that an automobile brake disc with high density, good appearance, no cracks, and good interface consistency can be obtained.

[0055] Comparative Example 1

[0056] Comparative Example 1 is basically the same as Example 1, except that the gas flow pressure into the melt furnace 20 is 0.03 MPa. After demolding, there are micro-cracks at the connection position of the friction layer and the structural layer on the back side of the hat, which cannot be completely removed by machining, and the brake disc is unqualified.

[0057] Example 2

[0058] An automobile brake disc with a hat sidewall height of 30 mm is prepared by using the steps of steps S110-S130, the temperature of the melt is controlled to be 740℃, the part of the upper die 12 for forming the end portion has a thickness of 30 mm, the part of the upper die 12 for forming the sidewall has a thickness of 25 mm, the pipe diameter of the riser 24 communicating with the mold cavity is 70 mm, the gas flow pressure into the melt furnace 20 is 0.15 MPa, and the holding time is 25 s. An automobile brake disc with good appearance, no cracks, and good interface consistency can be obtained.

[0059] Comparative Example 2

[0060] Comparative Example 2 is basically the same as Example 2, except that the gas flow pressure into the melt furnace 20 is 0.03 MPa. After demolding, there are micro-cracks at the connection position of the friction layer and the structural layer on the back side of the hat, which cannot be completely removed by machining, and the brake disc is unqualified.

[0061] Example 3

[0062] An automobile brake disc with a hat sidewall height of 45 mm is prepared by using the steps of steps S110-S130, and forging densification is performed after demolding and before machining, the temperature of the melt is controlled to be 720℃, the part of the upper die 12 for forming the end portion has a thickness of 25 mm, the part of the upper die 12 for forming the sidewall has a thickness of 20 mm, the pipe diameter of the riser 24 communicating with the mold cavity is 60 mm, the gas flow pressure into the melt furnace 20 is 0.10 MPa, and the holding time is 20 s. An automobile brake disc with good appearance, no cracks, and good interface consistency can be obtained.

[0063] Comparative Example 3

[0064] Comparative Example 3 is basically the same as Example 3, except that the forging step is omitted, and as a result, the brake disc fails to pass the bench test.

[0065] The above-described examples only express several embodiments of the present application, and the description is relatively specific and detailed, but it should not be understood as limiting the scope of the patent of the present application. It should be noted that for ordinary skilled persons in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which are within the scope of protection of the present application. Therefore, the protection scope of the patent of the present application should be subject to the appended claims.

Claims

1. A method for preparing an automobile brake disc, wherein the automobile brake disc comprises an annular disc body and a disc cap, wherein the disc cap comprises an end portion, a sidewall extending axially along the end portion, and a connecting portion extending radially along the sidewall, wherein: The method for preparing the automobile brake disc comprises the following steps: Providing the annular disc body; A mold is provided, the mold comprising a coaxially arranged upper mold, a lower mold, and a female mold. After the molds are closed, the upper mold and the lower mold enclose the female mold to form a mold cavity. The mold cavity comprises a first portion and a second portion that are interconnected. The first portion is adapted to fit the annular disk body, and the second portion is adapted to fit the disk cap to be formed. A cooling device is provided in the portion of the upper mold used to form the disk cap. A melt furnace is provided, comprising a furnace body and a riser tube, wherein one end of the riser tube is located in the furnace body and the other end passes through the center of the lower mold and communicates with the mold cavity; a ceramic reinforced aluminum-based composite material melt is contained in the furnace body; The annular disc body is placed in the first part of the mold cavity, preheated to 200°C to 250°C after the mold is closed, the cooling device is started, the air flow pressure entering the furnace body is controlled to be 0.05MPa to 0.15MPa, the ceramic reinforced aluminum-based composite material melt is compressed to enter the mold cavity through the riser tube, and after maintaining the pressure for 10s to 25s, the pressure is released, the mold is demolded, and machining is performed to obtain an automobile brake disc.

2. The method for preparing an automobile brake disc according to claim 1, characterized in that: The diameter of the riser pipe at the connection point with the mold cavity is 50 mm to 70 mm.

3. The method for preparing an automobile brake disc according to claim 1, characterized in that: The thickness of the portion of the upper die used to form the end portion is 20 mm to 30 mm; the thickness of the portion of the upper die used to form the side wall is 15 mm to 25 mm.

4. The method for preparing an automobile brake disc according to claim 1, characterized in that: The annular disc body includes an outer ring part and an inner ring part. The outer ring part is used for friction braking with the brake pad, and the inner ring part is used for engaging with the disc cap. The thickness of the inner ring part is smaller than that of the outer ring part.

5. The method for preparing an automobile brake disc according to claim 4, characterized in that: The inner ring portion is uniformly distributed with a plurality of axial through holes along the circumferential direction, and the diameter of each axial through hole is 8 mm to 16 mm.

6. The method for preparing an automobile brake disc according to claim 1, characterized in that: The ceramic reinforced aluminum-based composite material melt is composed of 10% to 20% ceramic reinforced particles and the balance aluminum alloy, and the annular disk is prepared from 35% to 55% ceramic reinforced particles and the balance aluminum alloy, and the aluminum alloy is selected from at least one of the second series aluminum alloy, the fourth series aluminum alloy and the sixth series aluminum alloy.

7. The method for preparing an automobile brake disc according to claim 1, characterized in that: The temperature of the ceramic reinforced aluminum-based composite material melt is 700° C. to 740° C.

8. The method for preparing an automobile brake disc according to claim 1, characterized in that: The cooling temperature is below 100°C.

9. The method for preparing an automobile brake disc according to any one of claims 1 to 8, characterized in that: The height of the side wall of the disk cap is 10 mm to 35 mm.

10. The method for preparing an automobile brake disc according to any one of claims 1 to 8, characterized in that: The height of the side wall of the disk cap is greater than 35 mm, and a densification step is also included between the demoulding and machining steps.

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