Preparation method of three-layer integrated brake disc

Abstract

The invention relates to a preparation method of a three-layer integrated brake disc. Through arrangement of an annular spacer, mutual invasion of a disc body friction material and a disc cap structure material in the powder filling process can be effectively avoided; before mold closing and pressing, the surface roughly the same as the inner surface is pressed through the pre-pressing punch, and the problem that the pressing face of the upper mold makes contact with the uneven powder surface, and powder is likely to be scattered can be effectively solved; the steps are coordinated, so that the friction material of the disc body and the structural material of the disc cap are respectively arranged in place, the interface consistency of the three-layer integrated brake disc can be effectively guaranteed, the performance of the disc body and the performance of the disc cap are guaranteed, and the batch stability is also guaranteed.

Description

Technical Field

[0001] The invention relates to the technical field of brake disc preparation, and in particular to a method for preparing a three-layer integrated brake disc. Background Art

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

[0003] Silicon carbide particle reinforced aluminum-based composite materials have low density, high specific strength and specific stiffness, high thermal conductivity, and excellent antibacterial, wear-resistant and corrosion-resistant properties. They have broad application prospects in the field of lightweight structural parts. The use of silicon carbide particle reinforced aluminum-based composite materials to replace traditional brake disc materials has also become the main research direction for lightweight transportation vehicles.

[0004] However, most brake discs produced by casting methods currently have difficulty breaking the upper limit of 20% ceramic particle content, and it is difficult to significantly improve wear resistance, which limits their promotion and application. Although the brake discs produced by powder metallurgy can have a ceramic particle content of up to 75%, which significantly improves wear resistance, the difficulty of production also increases.

[0005] CN111442039A discloses a method for preparing a lightweight, wear-resistant aluminum-based powder metallurgy composite material automobile brake disc, which comprises filling the wear-resistant aluminum-based composite material mixed powder and the aluminum-based structural material mixed powder into the corresponding areas of the automobile brake disc mold, cold pressing and demolding at room temperature to obtain an automobile brake disc blank; the blank is then sintered and hot pressed to shape, and finally machined. However, this method is only suitable for preparing a three-layer integrated disc in which the friction layer of the disc body is directly bonded to the side wall of the disc cap. When it is used to prepare the three-layer integrated disc in which the friction layer of the disc body is bonded to the connecting part of the disc cap of the present application, the problem of inconsistent interfaces will occur. In addition to affecting the appearance of the product, inconsistent interfaces will also lead to inconsistent dynamic balance removal of each disc, and the weight difference of the finished discs will be obvious, which will affect the batch stability. In addition, the friction material and the structural material will invade each other, which will affect the performance of the disc body and the disc cap. Summary of the invention

[0006] Based on this, it is necessary to provide a method for preparing a three-layer integrated brake disc that can ensure interface consistency.

[0007] A method for preparing a three-layer integrated brake disc, the three-layer integrated brake disc comprising an annular disc body and a disc cap, the disc cap comprising an end, a side wall extending axially along the end, and a connecting portion extending radially along the side wall, the annular disc body is connected to the connecting portion, a side of the three-layer integrated brake disc disc cap protruding relative to the disc body is an outer surface, and a side opposite to the outer surface is an inner surface, the method for preparing the three-layer integrated brake disc comprises the following steps:

[0008] A brake disc mold is provided, wherein the brake disc mold comprises an upper mold, a lower mold and a female mold which are coaxially arranged. After the molds are closed, the upper mold and the lower mold are enclosed in the female mold to form a mold cavity, the pressing surface of the lower mold is matched with the outer surface, and the pressing surface of the upper mold is matched with the inner surface;

[0009] Providing an annular spacer, wherein the outer diameter of the annular spacer is less than or equal to the outer diameter of the connecting portion;

[0010] Provide friction materials and structural materials;

[0011] Providing a pre-pressing punch, wherein the pressing surface of the pre-pressing punch is adapted to the inner surface and is provided with a recess adapted to the annular spacer;

[0012] The annular spacer is coaxially placed in the mold cavity, the mold cavity is divided into a disk body mold cavity and a disk cap mold cavity, the structural material is laid in the disk cap mold cavity, and the friction material and structural material are laid in the disk body mold cavity to obtain a disk body structure with structural material in the middle and friction material on both sides;

[0013] The pre-pressing punch is pressed downward to form a surface substantially the same as the inner surface, and then the pre-pressing punch and the annular spacer are removed, the mold is closed for pressing, and the mold is demolded to obtain a green body;

[0014] In a protective gas atmosphere, the green compact is sintered and then cooled to obtain a three-layer integrated brake disc.

[0015] In one embodiment, the steps of laying the friction material and the structural material in the disc mold cavity to obtain a disc structure with the structural material in the middle and the friction material on both sides are specifically as follows:

[0016] After laying the friction material in the disc body mold cavity, a first joint surface with regular pits or grooves is pressed out, and after laying the structural material on the first joint surface, a second joint surface mirror-symmetrical to the first joint surface is pressed out, and after laying the friction material on the second joint surface, a disc body structure with structural material in the middle and friction material on both sides is obtained.

[0017] In one embodiment, the depth of the pit or groove is 5 mm to 10 mm.

[0018] In one embodiment, the thickness of the annular spacer is 0.5 mm to 1.0 mm.

[0019] In one embodiment, the outer diameter of the annular spacer is 10 mm to 15 mm smaller than the outer diameter of the connecting portion.

[0020] In one of the embodiments, the downward pressure of the pre-pressing punch is 1.5 kPa to 5 kPa.

[0021] In one embodiment, the mold pressing pressure is 180MPa to 250MPa, and the pressure is maintained for 8s to 15s.

[0022] In one embodiment, the sintering temperature is 560°C to 650°C.

[0023] In one of the embodiments, during the sintering process, the green compact is placed with the side corresponding to the outer surface facing upward.

[0024] In one embodiment, the cooling condition is: cooling to below 300° C. in the furnace.

[0025] In the preparation method of the above-mentioned three-layer integrated brake disc, the provision of the annular spacer can effectively prevent the friction material of the disc body and the structural material of the disc cap from invading each other during the powder filling process; using a pre-pressing punch to press out a surface roughly the same as the inner surface before mold pressing can effectively prevent the upper mold pressing surface from contacting the uneven powder surface, which can easily lead to the problem of powder dispersion; the above-mentioned steps work together to ensure that the friction material of the disc body and the structural material of the disc cap are in their proper places, which can effectively ensure the interface consistency of the three-layer integrated brake disc, thereby ensuring both the performance of the disc body and the disc cap, and the batch stability. DETAILED DESCRIPTION

[0026] In order to facilitate the understanding of the present invention, the present invention will be described more comprehensively below, and preferred embodiments of the present invention are provided. However, the present invention can be implemented 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 understanding of the disclosure of the present invention more thorough and comprehensive.

[0027] It should be noted that when an element is referred to as being "disposed" on another element, it may be directly on the other element or there may be an intermediate element. When an element is considered to be "connected" to another element, it may be directly connected to the other element or there may be an intermediate element at the same time.

[0028] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those generally understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0029] It should be noted that the three-layer integrated brake disc of the present application includes an annular disc body and a disc cap, wherein the disc cap includes an end, a side wall extending axially along the end, and a connecting portion extending radially along the side wall, and the annular disc body is connected to the connecting portion.

[0030] For the convenience of description, the side of the three-layer integrated brake disc cap that protrudes relative to the disc body is the outer surface, and the side opposite to the outer surface is the inner surface.

[0031] The method for preparing the three-layer integrated brake disc comprises the following steps S110 to S170:

[0032] S110. Provide a brake disc mold.

[0033] The brake disc mold comprises an upper mold, a lower mold and a female mold which are coaxially arranged. After the molds are closed, the upper mold and the lower mold are enclosed in the female mold to form a mold cavity.

[0034] Furthermore, the pressing surface of the lower die is matched with the outer surface, and the pressing surface of the upper die is matched with the inner surface.

[0035] It should be noted that the mold cavity formed after the above-mentioned brake disc mold is closed is compatible with the three-layer integrated brake disc to be prepared, so the desired product can be obtained through subsequent sintering and densification without the need for further shaping.

[0036] S120. Provide an annular spacer.

[0037] The outer diameter of the annular spacer is less than or equal to the outer diameter of the connecting portion, so as to prevent the structural material used to prepare the disc cap from invading the friction material of the disc body, thereby affecting the friction and wear performance of the friction surface.

[0038] Furthermore, the outer diameter of the annular spacer is 10 mm to 15 mm smaller than the outer diameter of the connecting portion. It is understood that if the outer diameter of the annular spacer is too much smaller than the outer diameter of the connecting portion, the friction layer of the disc body will be too close to the side wall of the disc cap, thereby affecting the structural strength of the disc cap.

[0039] Furthermore, the thickness of the annular spacer is 0.5 mm to 1.0 mm. If the annular spacer is too thick, it is easy to drive the surrounding powder to move when it is removed later, so that the uniformity of the interface cannot be guaranteed; if the annular spacer is too thin, the preparation cost is high and it cannot guarantee an effective barrier effect during the powder filling and pre-pressing process.

[0040] S130. Provide friction materials and structural materials.

[0041] In this embodiment, the friction material is composed of 40% to 55% by mass of ceramic particles and the balance is a secondary aluminum alloy. The structural material is composed of 10% to 15% by mass of ceramic particles and the balance is a secondary aluminum alloy.

[0042] Among them, the second series aluminum alloy is an aluminum alloy with copper as the main alloying element, including 2A16 aluminum alloy (the aluminum alloy is mainly composed of 0.3% Si, 0.3% Fe, 6.0%-7.0% Cu, 0.4%-0.8% Mn, 0.05% Mg, 0.10% Zn, 0.10%-0.20% Ti, 0.20% Zr and the balance Al), 2324 aluminum alloy (the aluminum alloy is mainly composed of 3.8%-4.9% Cu, 0.3%-1.0% Mn, 1.2%-1.8% Mg, 0.10% Cr, 0.50% Si, 0.25% Zn and the balance Al), etc.

[0043] The use of the above-mentioned friction material and structural material to prepare a disc structure with structural material in the middle and friction material on both sides can reduce the weight of the brake disc to a greater extent, and reduce energy consumption to the greatest extent while meeting the friction performance.

[0044] S140, providing a pre-pressing punch.

[0045] The pressing surface of the pre-pressing punch is matched with the inner surface and is provided with a recess matched with the annular spacer. When pressed down, the pressing surface of the pre-pressing punch contacts the powder in the disc body cavity and the disc cap cavity, and the annular spacer is stuck in the recess.

[0046] S150, coaxially placing an annular spacer in the mold cavity, dividing the mold cavity into a disk body mold cavity and a disk cap mold cavity, laying structural material in the disk cap mold cavity, laying friction material and structural material in the disk body mold cavity, to obtain a disk body structure with structural material in the middle and friction material on both sides.

[0047] Furthermore, the steps of laying the friction material and the structural material in the disc body mold cavity to obtain a disc body structure with the structural material in the middle and the friction material on both sides are specifically as follows:

[0048] After laying the friction material in the disc body mold cavity, a first joint surface with regular pits or grooves is pressed out, and after laying the structural material on the first joint surface, a second joint surface with mirror symmetry to the first joint surface is pressed out, and after laying the friction material on the second joint surface, a disc body structure with structural material in the middle and friction material on both sides is obtained.

[0049] Furthermore, the depth of the groove or pit is 5 mm to 10 mm to increase the contact area between the two adjacent layers and improve the bonding force between the two adjacent layers. It can be understood that the depth of the groove or pit cannot be too deep, which will excessively occupy the area of ​​the friction surface layer, resulting in damage to the friction and heat resistance of the friction surface layer.

[0050] S160, the pre-pressing punch is pressed downward to form a surface substantially the same as the inner surface as a whole, and then the pre-pressing punch and the annular spacer are removed, the mold is closed for pressing, and the mold is demolded to obtain a green body.

[0051] In this embodiment, the pressure of the pre-pressing punch is 1.5 kPa to 5 kPa. The pressure of the pre-pressing punch cannot be too large, otherwise the powder will be squeezed out from the gap of the pre-pressing punch; the pressure of the pre-pressing punch cannot be too small, otherwise it will not be able to press out a surface that is roughly the same as the inner surface.

[0052] Before mold closing and pressing, use the pre-pressing punch to press down to make the uneven surface formed by the filling powder flat, so that during the subsequent mold closing and pressing, the upper mold pressing surface can completely fit with the powder surface to prevent the powder from being dispersed during the pressing process, causing the friction material of the disc body and the disc cap structure material to invade each other, and then causing inconsistent interfaces.

[0053] Furthermore, the mold closing and pressing pressure is 180MPa to 250MPa, and the pressure is maintained for 8s to 15s.

[0054] S170, in a protective gas atmosphere, sintering the green compact and then cooling it to obtain a three-layer integrated brake disc.

[0055] The protective gas atmosphere is an inert gas atmosphere such as nitrogen and argon.

[0056] Furthermore, the sintering temperature is 560° C. to 650° C., and during the sintering process, the side of the green body corresponding to the outer surface is placed upward to prevent the material from softening during the sintering process and the friction material layer from collapsing in mid-air.

[0057] Furthermore, the cooling condition is to cool the furnace to below 300°C.

[0058] When the three-layer integrated brake disc is prepared by the above method, the disc cap mold cavity and the disc body mold cavity can be filled with powder at the same time, which saves powder filling time compared with the processes of pre-pressing and forming one cavity first and then filling the other cavity with powder; the disc cap can be formed in the forming stage, omitting the subsequent shaping and machining processes, saving production costs.

[0059] The following are specific embodiments.

[0060] Example 1

[0061] A three-layer integrated brake disc is prepared by adopting steps such as steps S110 to S170, wherein the friction material consists of 40% by mass of ceramic particles and the remainder is 2A16 aluminum alloy, the structural material consists of 15% by mass of ceramic particles and the remainder is 2A16 aluminum alloy, the depth of the pit is 5 mm, the thickness of the annular spacer is 0.5 mm, the outer diameter of the annular spacer is 10 mm smaller than the outer diameter of the connecting part, the downward pressure of the pre-pressing punch is 1.5 kPa, the pressure of the mold pressing is 180 MPa, the pressure is maintained for 15 seconds, and the sintering temperature is 560°C.

[0062] After observation, the three-layer integrated brake disc prepared in Example 1 has a uniform interface and the product dimensional accuracy meets the requirements. The three-layer integrated brake disc prepared in Example 1 was subjected to bench testing and completed and passed the T / CAAMTB 09-2018 high load and Jaso C 419-2006 torsion failure bench tests, indicating that the brake disc structural strength and friction and wear performance meet the requirements of the brake disc.

[0063] Example 2

[0064] A three-layer integrated brake disc is prepared by steps S110 to S170, wherein the friction material consists of 55% by mass of ceramic particles and the remainder of 2324 aluminum alloy, the structural material consists of 10% by mass of ceramic particles and the remainder of 2A16 aluminum alloy, the depth of the pit is 10 mm, the thickness of the annular spacer is 1.0 mm, the outer diameter of the annular spacer is 15 mm smaller than the outer diameter of the connecting part, the downward pressure of the pre-pressing punch is 5 kPa, the pressure of the mold pressing is 250 MPa, the pressure is maintained for 8 seconds, and the sintering temperature is 650°C.

[0065] After observation, the three-layer integrated brake disc prepared in Example 2 has a uniform interface and the product dimensional accuracy meets the requirements. The three-layer integrated brake disc prepared in Example 2 was subjected to bench testing and completed and passed the T / CAAMTB 09-2018 high load and Jaso C 419-2006 torsion failure bench tests, indicating that the brake disc structural strength and friction and wear performance meet the requirements of the brake disc.

[0066] Example 3

[0067] A three-layer integrated brake disc is prepared by adopting steps such as steps S110 to S170, wherein the friction material consists of 50% by mass of ceramic particles and the remainder of 2324 aluminum alloy, the structural material consists of 12% by mass of ceramic particles and the remainder of 2324 aluminum alloy, the depth of the pit is 5 mm, the thickness of the annular spacer is 0.5 mm, the outer diameter of the annular spacer is 12 mm smaller than the outer diameter of the connecting part, the downward pressure of the pre-pressing punch is 2 kPa, the pressure of the mold pressing is 200 MPa, the pressure is maintained for 12 seconds, and the sintering temperature is 600°C.

[0068] After observation, the three-layer integrated brake disc prepared in Example 3 has a uniform interface and the product dimensional accuracy meets the requirements. The three-layer integrated brake disc prepared in Example 3 was subjected to bench testing and completed and passed the T / CAAMTB 09-2018 high load and Jaso C 419-2006 torsion failure bench tests, indicating that the brake disc structural strength and friction and wear performance meet the requirements of the brake disc.

[0069] Comparative Example 1

[0070] Comparative Example 1 is substantially the same as Example 3, except that the step of pressing down the pre-pressing punch in S160 is omitted in Comparative Example 1.

[0071] It was observed that the interface of the three-layer integrated brake disc prepared in Comparative Example 1 was irregular in shape and had no consistency at all.

[0072] Comparative Example 2

[0073] Comparative Example 2 is substantially the same as Example 3, except that no annular spacer is used for isolation in Comparative Example 3.

[0074] It was observed that the interface position of the three-layer integrated brake disc prepared in Comparative Example 2 fluctuated significantly.

[0075] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the patent of the present invention. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A method for preparing a three-layer integrated brake disc, wherein the three-layer integrated brake disc comprises an annular disc body and a disc cap, wherein the disc cap comprises an end, a side wall extending axially along the end, and a connecting portion radially along the side wall, wherein the annular disc body is connected to the connecting portion, wherein a side of the three-layer integrated brake disc disc cap protruding relative to the disc body is an outer surface, and a side opposite to the outer surface is an inner surface, wherein: The method for preparing the three-layer integrated brake disc comprises the following steps: A brake disc mold is provided, wherein the brake disc mold comprises an upper mold, a lower mold and a female mold which are coaxially arranged. After the molds are closed, the upper mold and the lower mold are enclosed in the female mold to form a mold cavity, the pressing surface of the lower mold is matched with the outer surface, and the pressing surface of the upper mold is matched with the inner surface; Providing an annular spacer, wherein the outer diameter of the annular spacer is less than or equal to the outer diameter of the connecting portion; Provide friction materials and structural materials; Providing a pre-pressing punch, wherein the pressing surface of the pre-pressing punch is adapted to the inner surface and is provided with a recess adapted to the annular spacer; The annular spacer is coaxially placed in the mold cavity, the mold cavity is divided into a disk body mold cavity and a disk cap mold cavity, the structural material is laid in the disk cap mold cavity, and the friction material and structural material are laid in the disk body mold cavity to obtain a disk body structure with structural material in the middle and friction material on both sides; The pre-pressing punch is pressed downward to form a surface substantially the same as the inner surface, and then the pre-pressing punch and the annular spacer are removed, the mold is closed for pressing, and the mold is demolded to obtain a green body; In a protective gas atmosphere, the green compact is sintered and then cooled to obtain a three-layer integrated brake disc.

2. The method for preparing a three-layer integrated brake disc according to claim 1, characterized in that: The steps of laying the friction material and the structural material in the disc body mold cavity to obtain a disc body structure with the structural material in the middle and the friction material on both sides are specifically: After laying the friction material in the disc body mold cavity, a first joint surface with regular pits or grooves is pressed out, and after laying the structural material on the first joint surface, a second joint surface mirror-symmetrical to the first joint surface is pressed out, and after laying the friction material on the second joint surface, a disc body structure with structural material in the middle and friction material on both sides is obtained.

3. The method for preparing a three-layer integrated brake disc according to claim 2, characterized in that: The depth of the pit or groove is 5 mm to 10 mm.

4. The method for preparing a three-layer integrated brake disc according to any one of claims 1 to 3, characterized in that: The thickness of the annular spacer is 0.5 mm to 1.0 mm.

5. The method for preparing a three-layer integrated brake disc according to any one of claims 1 to 3, characterized in that: The outer diameter of the annular spacer is 10 mm to 15 mm smaller than the outer diameter of the connecting portion.

6. The method for preparing a three-layer integrated brake disc according to any one of claims 1 to 3, characterized in that: The downward pressure of the pre-pressing punch is 1.5 kPa to 5 kPa.

7. The method for preparing a three-layer integrated brake disc according to any one of claims 1 to 3, characterized in that: The pressure of the mold closing and pressing is 180MPa to 250MPa, and the pressure is maintained for 8 to 15s.

8. The method for preparing a three-layer integrated brake disc according to any one of claims 1 to 3, characterized in that: The sintering temperature is 560°C to 650°C.

9. The method for preparing a three-layer integrated brake disc according to any one of claims 1 to 3, characterized in that: During the sintering process, the green compact is placed with the side corresponding to the outer surface facing upward.

10. The method for preparing a three-layer integrated brake disc according to any one of claims 1 to 3, characterized in that: The cooling condition is: cooling to below 300° C. in the furnace.