Friction particle auxiliary sintering tool and friction particle sintering equipment and process

Abstract

The invention discloses a friction particle auxiliary sintering tool, friction particle sintering equipment and a friction particle sintering process, relates to the technical field of powder metallurgy brake pad manufacturing, and is used for inhibiting expansion deformation in the friction particle sintering process and improving the sintering yield. The friction particle auxiliary sintering tool comprises a top plate, a bottom plate and at least two opposite side plates. The two ends of the side plates are connected with the top plate and the bottom plate correspondingly and define at least one limiting cavity used for containing friction particles, the height of the limiting cavity is consistent with that of the friction particles to be sintered, a lateral opening is formed between the side plates and used for taking and placing the friction particles, and the top plate and the bottom plate vertically limit the upper surfaces and the lower surfaces of the friction particles correspondingly. The side plates horizontally limit the side faces of the friction particles. The friction particle sintering equipment comprises a chain belt type sintering furnace and the friction particle sintering tool.

Description

Technical Field

[0001] The present invention relates to the technical field of powder metallurgy brake pad manufacturing, and particularly to a friction particle assisted sintering tooling, a friction particle sintering device and a process. Background Art

[0002] Sintering is a process of heating a powder compact to a temperature below the melting point of its matrix composition and then cooling it to room temperature at a certain method and speed. After sintering, bonding occurs between powder particles, the strength of the sintered body increases, and the powder particle aggregate transforms into a grain coalescence body, thereby obtaining a product or material with the required physical and mechanical properties.

[0003] The friction particle sintering process of powder metallurgy brake pads is a process of first expanding and then contracting. Generally, the expansion amount is greater than the contraction amount, and a high requirement is imposed on the consistency of the thickness of the friction particles. Therefore, pressure needs to be applied during sintering to control the expansion of the friction particles. When the friction particles of powder metallurgy brake pads are sintered in a chain belt furnace, the green compact enters from one end of the furnace by means of the chain belt, and the product is conveyed out from the other end. However, the chain belt of the belt furnace cannot withstand the required pressure, and the existing process cannot control the loose cracks and poor adhesion caused by the sintering expansion problem of the friction particles of powder metallurgy brake pads by applying pressure, resulting in a decrease in the sintering yield and even the scrapping of the entire furnace. Summary of the Invention

[0004] The purpose of the present invention is to provide a friction particle assisted sintering tooling, a friction particle sintering device and a process for suppressing the expansion deformation during the sintering process of friction particles and improving the sintering yield.

[0005] To achieve the above purpose, in the first aspect, the present invention provides a friction particle assisted sintering tooling, including a top plate, a bottom plate and at least two opposite side plates; both ends of the side plates are respectively connected to the top plate and the bottom plate, and enclose to form at least one limiting cavity for accommodating friction particles. The height of the limiting cavity is the same as the height of the friction particles to be sintered. There is a lateral opening between the side plates for taking and placing the friction particles. The top plate and the bottom plate respectively perform vertical limiting on the upper and lower surfaces of the friction particles, and the side plates perform horizontal limiting on the side surfaces of the friction particles.

[0006] Compared with the prior art, when using the friction particle assisted sintering tooling provided by the present invention for sintering friction particles, first place the friction particle blank in the friction particle assisted sintering tooling. Place the friction particle assisted sintering tooling containing the friction particle blank on the chain of the chain belt type sintering furnace. During the sintering process, the chain of the chain belt type sintering furnace drives the tooling to move, so that the friction particle blank enters the furnace chamber to be heated. The friction particle assisted sintering tooling is composed of a top plate, a bottom plate and at least two opposite side plates. The two ends of the side plates are connected to the top plate and the bottom plate, enclosing a limiting cavity with the same height as the friction particles to be sintered. The top plate and the bottom plate respectively perform vertical limiting on the friction particles from the upper and lower surfaces to prevent them from expanding excessively in the vertical direction; the side plates perform horizontal limiting on the sides of the friction particles to ensure that the friction particles are stably placed in the friction particle assisted sintering tooling during sintering. At the same time, a lateral opening is provided between the side plates, which is convenient for taking out or placing the friction particles in the friction particle assisted sintering tooling. Through this all-round limiting method, only by placing the friction particle blank in the friction particle assisted sintering tooling without applying pressure, the limiting effect on the friction particles can be achieved, effectively inhibiting the expansion and deformation of the friction particles during sintering, ensuring the dimensional accuracy of the product, improving the sintering yield, and providing a strong guarantee for the high-quality sintering of the powder metallurgy brake pad friction particles. In addition, compared with the existing bell-type sintering furnace, this friction particle assisted sintering tooling is flexible in use and convenient to operate, abandoning the cumbersome processes such as stacking layer by layer and buckling the cover and applying pressure in the bell-type furnace, and has a simple structure. Its volume is only equivalent to that of the friction particles and does not occupy a large space.

[0007] Optionally, in the above-mentioned friction particle assisted sintering tooling, the number of side plates is two, and they are arranged parallel to the bottom plate. The two side plates, the top plate and the bottom plate enclose a strip-shaped limiting cavity with openings on both sides.

[0008] Optionally, in the above-mentioned friction particle assisted sintering tooling, the materials of the top plate, the bottom plate and the side plates are graphite or graphite composite materials.

[0009] Optionally, in the above-mentioned friction particle assisted sintering tooling, horizontal supporting steps are provided on the inner surfaces of at least two opposite side plates, and the supporting steps are used to support the green compact of the friction particles.

[0010] Optionally, in the above-mentioned friction particle assisted sintering tooling, the top plate, the side plates and the bottom plate are of an integrally formed structure.

[0011] In a second aspect, the present invention provides a friction particle sintering device, which includes:

[0012] A chain belt type sintering furnace;

[0013] Any of the above-mentioned friction particle assisted sintering toolings, and the friction particle assisted sintering tooling is arranged on the chain of the chain belt type sintering furnace and is synchronously conveyed along with the chain movement.

[0014] Compared with the prior art, when using the friction particle-assisted sintering tooling provided by the present invention to sinter friction particles, first place the friction particle blank in the tooling, and then place the friction particle-assisted sintering tooling with the blank on the conveyor belt of a belt-type sintering furnace. During the sintering process, the conveyor belt drives the tooling to move, enabling the blank to enter the furnace chamber and be heated. The tooling encloses a limiting cavity that is height-adapted to the friction particles. The top plate and the bottom plate provide vertical limitation, and the side plates provide horizontal limitation, comprehensively suppressing the expansion and deformation of the friction particles, ensuring the dimensional accuracy of the product, improving the sintering yield rate, and providing guarantee for high-quality sintering. Compared with the existing bell-type sintering furnace, the friction particle-assisted sintering tooling of the present invention has a simple structure, eliminating the cumbersome processes of layer-by-layer stacking and cover pressing in the bell-type furnace. Only need to place the blank in the limiting cavity of the tooling, place the tooling on the conveyor belt, and complete the sintering process by means of conveyor belt transportation, which is convenient to operate. At the same time, the belt-type sintering furnace in cooperation with the tooling can achieve continuous production, changing the intermittent sintering mode of the bell-type furnace where each furnace needs to go through heating, heat preservation, and cooling, greatly improving the production efficiency, and avoiding the disadvantages of the bell-type furnace where the waste heat cannot be recycled and the energy waste is serious, significantly reducing the energy consumption, and improving the production efficiency while ensuring the product quality.

[0015] In a third aspect, the present invention provides a friction particle sintering process, and the process includes the following steps:

[0016] Fix the green compact and the skeleton to form a friction particle blank;

[0017] Place the friction particle blank in the limiting cavity of the friction particle-assisted sintering tooling as described in any one of the above;

[0018] Place the friction particle-assisted sintering tooling on the conveyor belt of a belt-type sintering furnace, and sinter the friction particle blank under the protection of a protective gas;

[0019] Cool the sintered friction particles to obtain a formed pearlite structure friction particle product.

[0020] Compared with the prior art, in the whole process, the green compact and the skeleton are first firmly fixed to form a frictional particle blank. Then, the blank is placed in the limiting cavity of the frictional particle-assisted sintering tooling. The tooling can accurately limit the frictional particles in all directions, effectively suppressing their expansion and deformation during sintering and ensuring the dimensional accuracy of the product. The tooling containing the blank is placed on the chain of the belt-type sintering furnace, and sintering is carried out under the protective atmosphere created by the protective gas. The close cooperation between the belt-type sintering furnace and the tooling has changed the intermittent sintering mode of the traditional bell-type furnace, realized continuous production, improved production efficiency, and at the same time solved the problems of waste heat waste and high energy consumption of the bell-type furnace. After sintering, the formed pearlite structure frictional particle finished product is obtained through cooling treatment. This process avoids the problems of low finished product rate caused by the inability to control expansion when using the belt-type furnace alone, and the cumbersome process, energy waste and low efficiency when using the bell-type furnace alone. The operation process is simple, the obtained product has high quality and excellent energy-saving effect, significantly improving the production benefit, and providing guarantee for the high-quality and high-efficiency production of powder metallurgy brake pad frictional particles.

[0021] Optionally, in the above frictional particle sintering process, placing the frictional particle blank in the limiting cavity of any of the above frictional particle-assisted sintering toolings includes: placing the frictional particle blank in the limiting cavity of any of the above frictional particle-assisted sintering toolings with the skeleton located below and the green compact located above.

[0022] Optionally, in the above frictional particle sintering process, placing the frictional particle-assisted sintering tooling on the chain of the belt-type sintering furnace and sintering the frictional particle blank under the protection of the protective gas includes:

[0023] Introducing a protective gas into the belt-type sintering furnace as the protective atmosphere;

[0024] Placing the frictional particle-assisted sintering tooling on the chain of the belt-type sintering furnace;

[0025] Driving the tooling to move in the belt-type sintering furnace by the chain of the belt-type sintering furnace and performing segmented step heating; wherein, the running speed of the chain is 25 mm / min - 35 mm / min, and the segmented step heating sequentially includes:

[0026] Heat in the first heating section with a first preset length, and the heating temperature is 80°C - 100°C; heat in the second heating section with a second preset length, and the heating temperature is 100°C - 300°C; heat in the third heating section with a third preset length, and the heating temperature is 300°C - 500°C; heat in the fourth heating section with a fourth preset length, and the heating temperature is 500°C - 700°C; heat in the fifth heating section with a fifth preset length, and the heating temperature is 700°C - 900°C; heat in the sixth heating section with a sixth preset length, and the heating temperature is 900°C - 1100°C.

[0027] Optionally, in the above-mentioned friction particle sintering process, cool the sintered friction particles to obtain the formed pearlite structure friction particle finished product, including: cooling the friction particles by using a circulating water cooling jacket and air cooling with inert gas to obtain the formed pearlite structure friction particle finished product. Description of the Drawings

[0028] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention. In the drawings:

[0029] Figure 1 It is a schematic diagram of the overall structure of a friction particle assisted sintering tooling cooperating with a friction particle blank provided by an embodiment of the present invention;

[0030] Figure 2 It is a schematic cross-sectional view of a friction particle assisted sintering tooling cooperating with a friction particle blank provided by an embodiment of the present invention;

[0031] Figure 3 It is a schematic diagram of the overall structure of a friction particle assisted sintering device provided by an embodiment of the present invention;

[0032] Figure 4 It is a schematic diagram of the structural diagram of a friction particle assisted sintering device provided by an embodiment of the present invention;

[0033] Figure 5 It is a flowchart of a friction particle assisted sintering process provided by an embodiment of the present invention.

[0034] Reference Signs:

[0035] 1 is a friction particle assisted sintering tooling, 10 is a top plate, 11 is a bottom plate, 12 is a side plate, 13 is a supporting step, 2 is a friction particle, 21 is a skeleton, 22 is a green compact, 3 is a chain belt type sintering furnace, 31 is a chain belt, 32 is a circulating water cooling jacket. Detailed Embodiments

[0036] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clear and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0037] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0038] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present invention, "a plurality of" means two or more unless otherwise specifically defined. "Several" means one or more unless otherwise specifically defined.

[0039] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "upper", "lower", "front", "rear", "left", "right", etc. is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus cannot be understood as a limitation of the present invention.

[0040] In the description of the present invention, it should be noted that unless otherwise clearly defined and limited, the terms "mounted", "connected" and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the internal communication of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0041] In a first aspect, please refer to Figure 1, an embodiment of the present invention provides a friction particle assisted sintering tooling 1, which includes a top plate 10, a bottom plate 11, and at least two opposite side plates 12; both ends of the side plates 12 are respectively connected to the top plate 10 and the bottom plate 11, and enclose at least one limiting cavity for accommodating the friction particles 2, the height of the limiting cavity is the same as the height of the friction particles 2 to be sintered, a lateral opening is provided between the side plates 12 for taking and placing the friction particles 2, the top plate 10 and the bottom plate 11 respectively perform vertical limiting on the upper and lower surfaces of the friction particles 2, and the side plates 12 perform horizontal limiting on the sides of the friction particles 2.

[0042] Specifically in implementation: When using the friction particle assisted sintering tooling 1 provided by the present invention to sinter the friction particles 2, first place the friction particle blank in the limiting cavity of the friction particle assisted sintering tooling 1, and then place the friction particle assisted sintering tooling 1 containing the friction particle blank on the chain belt 31 of the chain belt type sintering furnace 3. During the sintering process, the chain belt 31 of the chain belt type sintering furnace 3 drives the tooling to move, and brings the friction particle blank into the furnace chamber to be heated. The friction particle assisted sintering tooling 1 is composed of a top plate 10, a bottom plate 11, and at least two opposite side plates 12. Both ends of the side plates 12 are connected to the top plate 10 and the bottom plate 11, enclosing a limiting cavity with the same height as the friction particles 2 to be sintered. The top plate 10 and the bottom plate 11 respectively perform vertical limiting on the friction particles 2 from the upper and lower surfaces to prevent them from expanding excessively in the vertical direction; the side plates 12 perform horizontal limiting on the sides of the friction particles 2 to ensure that the friction particles 2 are stably placed in the friction particle assisted sintering tooling 1 during the sintering process. At the same time, the lateral opening provided between the side plates 12 facilitates taking out or placing the friction particles 2 into the friction particle assisted sintering tooling 1. Through this all-round limiting method, only by placing the friction particle blank in the friction particle assisted sintering tooling 1 without applying pressure, the limiting effect on the friction particles 2 can be achieved, effectively inhibiting the expansion and deformation of the friction particles 2 during the sintering process, ensuring the dimensional accuracy of the product, improving the sintering yield, and providing a strong guarantee for the sintering of high-quality powder metallurgy brake pad friction particles 2.

[0043] As a possible implementation, as Figure 1 shown, the number of the side plates 12 is two, and they are arranged in parallel on the bottom plate 11. The two side plates 12 and the top plate 10 and the bottom plate 11 enclose a strip-shaped limiting cavity with openings on both sides. Specifically, the bottom plate 11 serves as the basic support component, and the two parallel side plates 12 are vertically fixed thereon and then connected to the top plate 10, jointly enclosing a strip-shaped space, and this strip-shaped space presents a form with openings on both sides, which is convenient for taking and placing the friction particles 2.

[0044] In specific implementation: when the friction particles 2 of the powder metallurgy brake pad are sintered, the assembled friction particle blanks are placed into the strip-shaped limiting cavity through the openings on both sides. At this time, the top plate 10 and the bottom plate 11 limit the height of the friction particle blanks from the top and bottom directions to ensure that the friction particles 2 will not expand in the vertical direction during the sintering process; and the two parallel side plates 12 constrain the sides of the friction particle blanks from the horizontal direction to prevent instability during the sintering process. When the chain belt sintering furnace 3 is running, the friction particle auxiliary sintering tool 1 carrying the friction particle blanks continues to move with the chain belt 31, so that the friction particle blanks pass through the sintering furnace to complete the sintering process. When the sintering is completed, the chain belt 31 takes the friction particle auxiliary sintering tool 1 out of the sintering furnace, and takes out the sintered pearlite friction particle products through the openings on both sides. The design of the strip-shaped limiting cavity with openings on both sides of the friction particle auxiliary sintering tool 1 significantly improves the convenience of operation. Compared with fully enclosed or poorly designed tooling, the two-side opening form is easier and more efficient for placing the blank to be sintered or taking out the sintered finished product, saving manpower and time costs, and is especially suitable for frequent pick-and-place operations in large-scale production scenarios. While ensuring the limiting effect of the friction particles 2, the ventilation and gas circulation inside the tooling are taken into account. During the sintering process, the protective gas can enter the interior of the tooling more smoothly through the openings on both sides, surround the friction particle blank, ensure that it is sintered under a uniform protective atmosphere, effectively prevent oxidation, and improve the sintering quality.

[0045] In some embodiments, the friction particle auxiliary sintering tool 1 can be provided with three or more parallel side plates 12, and the adjacent side plates 12 are connected by the top plate 10, and two or more parallel strip-shaped limiting cavities are formed on the bottom plate 11, and the openings on both sides of each cavity are convenient for taking and placing the friction particles 2. The multi-cavity structure design enables a single tool to simultaneously process multiple friction particles 2, and the continuous conveying of the chain belt 31 is used to increase the production capacity, which can be applied to the continuous sintering production of large batches of brake pads.

[0046] As a possible implementation manner, the material of the top plate 10 , the bottom plate 11 and the side plate 12 is graphite or a graphite composite material.

[0047] Graphite and graphite composite materials have extremely stable physical properties. In a high-temperature sintering environment, they have outstanding thermal stability and will not expand or deform. This property enables the tooling formed by them to always maintain the precise size of the limiting cavity, providing a stable and reliable limiting space for the friction particles 2. During the sintering process of the friction particles 2, the friction particles 2 can be continuously and accurately limited in the vertical direction, effectively suppressing the expansion and deformation of the friction particles 2, thereby ensuring the stability of product quality and the forming rate.

[0048] Meanwhile, graphite and graphite composites have good chemical stability. During the sintering process, they will not adhere to the skeleton 21 of the friction particle 2 and the metal matrix composite product. This ensures the integrity of the friction particle 2 during the sintering process, enabling the product to be smoothly removed from the tooling after sintering, greatly improving production efficiency. Moreover, since the graphite tooling will not be damaged due to adhesion problems, its service life is extended, the replacement frequency of the tooling is reduced, and the production cost is lowered.

[0049] As a possible implementation, as Figure 1 or Figure 2 shown, horizontal extending supporting steps 13 are provided on the inner surfaces of at least two opposite side plates 12, and the supporting steps 13 are used to support the green compact 22 of the friction particle 2.

[0050] During specific implementation, the friction particle blank is placed in the limiting cavity of the tooling with the skeleton 21 below and the green compact 22 above. Through the horizontally arranged supporting steps 13, a stable support point can be provided for the green compact 22, so that the position of the green compact 22 in the limiting cavity is fixed. During the sintering process of driving the tooling and the friction particle blank by the chain belt 31 of the chain belt type sintering furnace 3, even affected by the vibration brought by the movement of the chain belt 31, the supporting steps 13 can still ensure that the relative position between the green compact 22 and the skeleton 21 remains stable. Such a design can prevent the overall structure change of the friction particle 2 caused by the position deviation of the green compact 22 during the sintering process, thereby ensuring the product quality, further ensuring the stable position of the green compact 22, improving the consistency and stability of sintering, making the friction particle 2 receive more uniform heat in all directions, and further improving the product yield.

[0051] As a possible implementation, as Figure 1 shown, the top plate 10, the side plates 12, and the bottom plate 11 are of an integrally formed structure. The integrally formed structure of the tooling avoids potential deformation hazards at the connection parts, enhances the overall structural strength and stability of the tooling, enables it to still maintain accurate limiting cavity dimensions during the transportation on the chain belt 31 and in a high-temperature environment, continuously provides reliable limiting for the friction particle 2, and effectively suppresses expansion deformation. In addition, the integral forming simplifies the processing and manufacturing process and improves production efficiency.

[0052] In a second aspect, please refer to Figure 3 or Figure 4 , an embodiment of the present invention provides a sintering device for friction particles 2, including a chain belt type sintering furnace 3 and any of the above-mentioned friction particle auxiliary sintering toolings 1. The friction particle auxiliary sintering tooling 1 is arranged on the chain belt 31 of the chain belt type sintering furnace 3 and is synchronously transported along with the movement of the chain belt 31.

[0053] In specific implementation, when sintering the friction particles 2 using the friction particle-assisted sintering tooling 1 provided by the present invention, first place the friction particle blank in the tooling, and then place the friction particle-assisted sintering tooling 1 with the blank on the conveyor belt 31 of the belt-type sintering furnace 3. During the sintering process, the conveyor belt 31 drives the tooling to move, causing the blank to enter the furnace chamber and be heated. The tooling is composed of a top plate 10, a bottom plate 11, and at least two opposite side plates 12, enclosing a limiting cavity that is height-adapted to the friction particles 2. The top plate 10 and the bottom plate 11 provide vertical limitation, and the side plates 12 provide horizontal limitation, comprehensively suppressing the expansion and deformation of the friction particles 2, ensuring the dimensional accuracy of the product, improving the sintering yield, and providing guarantee for high-quality sintering. Compared with the existing bell-type sintering furnace, the friction particle-assisted sintering tooling 1 of the present invention has a simple structure, eliminating the cumbersome processes of layer-by-layer stacking and cover pressing in the bell-type furnace. Only need to put the blank into the limiting cavity of the tooling, place the tooling on the conveyor belt 31, and the sintering process can be completed by means of the conveyor belt 31 transportation, which is convenient to operate. At the same time, the belt-type sintering furnace 3 and the tooling can realize continuous production, changing the intermittent sintering mode of the bell-type furnace that requires heating, heat preservation, and cooling for each furnace, greatly improving the production efficiency, and avoiding the disadvantages of the bell-type furnace that the waste heat cannot be recycled and the energy waste is serious, significantly reducing the energy consumption, and improving the production efficiency while ensuring the product quality.

[0054] In the third aspect, as Figure 5 shown, the embodiment of the present invention provides a friction particle 2 sintering process, and the process includes the following steps:

[0055] S100: Fix the green compact 22 and the skeleton 21 to form a friction particle blank;

[0056] S200: Place the friction particle blank into the limiting cavity of the friction particle-assisted sintering tooling 1 as described in any one of the above;

[0057] S300: Place the friction particle-assisted sintering tooling 1 on the conveyor belt 31 of the belt-type sintering furnace 3, and sinter the friction particle blank under the protection of a protective gas;

[0058] S400: Cool the sintered friction particles 2 to obtain a formed pearlite tissue friction particle finished product.

[0059] Compared with the prior art, in the whole process, first, the green compact 22 and the skeleton 21 are firmly fixed to form a friction particle blank. Then, the blank is placed in the limiting cavity of the friction particle assisted sintering tooling 1, which is enclosed by the top plate 10, the bottom plate 11 and the relative side plates 12. It can accurately limit the friction particles 2 in all directions, effectively inhibit their expansion and deformation during sintering, and ensure the dimensional accuracy of the product. The tooling containing the blank is placed on the conveyor belt 31 of the belt type sintering furnace 3, and sintering is carried out under the protective atmosphere created by the protective gas. The belt type sintering furnace 3 and the tooling are closely matched, changing the intermittent sintering mode of the traditional bell type furnace, realizing continuous production, improving the production efficiency, and at the same time solving the problems of waste of waste heat and high energy consumption of the bell type furnace. After sintering, the formed pearlite structure friction particle finished product is obtained through cooling treatment. This process avoids the problems of low finished product rate caused by the inability to control expansion when using the belt 31 type furnace alone, and the cumbersome process, energy waste and low efficiency when using the bell type furnace alone. The operation process is simple, the obtained product has high quality and excellent energy-saving effect, significantly improves the production benefit, and provides a guarantee for the high-quality and high-efficiency production of the powder metallurgy brake pad friction particles 2.

[0060] As a possible implementation method, placing the friction particle blank in the limiting cavity of any of the friction particle assisted sintering toolings 1 as described above includes: placing the friction particle blank in the limiting cavity of any of the friction particle assisted sintering toolings 1 with the skeleton 21 below and the green compact 22 above.

[0061] The friction particles 2 are composed of the green compact 22 and the skeleton 21. Before sintering, they are placed in the tooling according to a specific positional relationship, and this placement method is determined based on the physical change characteristics of the material during the sintering process. In a high-temperature sintering environment, some substances in the green compact 22 will be in a liquid and semi-solid state and have rheological properties. When placed with the skeleton 21 below and the green compact 22 above, under the action of gravity, the substances of the green compact 22 in the liquid and semi-solid state will flow towards the direction close to the skeleton 21, so that more sufficient contact and fusion can be achieved between the green compact 22 and the skeleton 21. In contrast, if the placement method of the green compact 22 below and the skeleton 21 above is adopted, due to the influence of gravity, the substances of the green compact 22 in the liquid and semi-solid state will move away from the skeleton 21, resulting in only partial adhesion at the surface contact part between the two, and it is difficult to achieve an ideal bonding effect. Such a placement method can improve the sintering quality of the friction particles 2. By promoting a closer and more comprehensive combination of the green compact 22 and the skeleton 21, the friction particles 2 are more stable in structure and better combined, meeting the high-quality requirements for the powder metallurgy brake pad friction particles 2 in practical applications.

[0062] As a possible implementation, place the friction particle-assisted sintering tooling 1 on the conveyor belt 31 of the belt-type sintering furnace 3, and sinter the friction particle blank under the protection of a protective gas, including: introducing a protective gas into the belt-type sintering furnace 3 as a protective atmosphere; placing the friction particle-assisted sintering tooling 1 on the conveyor belt 31 of the belt-type sintering furnace 3; driving the tooling to move in the belt-type sintering furnace 3 by the conveyor belt 31 of the belt-type sintering furnace 3, and performing segmented step heating; wherein, the running speed of the conveyor belt 31 is 25 mm / min - 35 mm / min, and the segmented step heating sequentially includes: heating in a first heating section with a first preset length, the heating temperature being 80°C - 100°C; heating in a second heating section with a second preset length, the heating temperature being 100°C - 300°C; heating in a third heating section with a third preset length, the heating temperature being 300°C - 500°C; heating in a fourth heating section with a fourth preset length, the heating temperature being 500°C - 700°C; heating in a fifth heating section with a fifth preset length, the heating temperature being 700°C - 900°C; heating in a sixth heating section with a sixth preset length, the heating temperature being 900°C - 1100°C.

[0063] Set the speed of the conveyor belt 31 to 8 mm / min - 60 mm / min. If the speed is less than 8 mm / min, it will cause the sintering time of the friction particle blank in the furnace to be too long, not only wasting energy but also reducing the overall production efficiency; if the speed is greater than 60 mm / min, the residence time of the friction particle blank in each temperature section is too short, and the corresponding physical and chemical changes cannot be fully completed, affecting the sintering quality, and problems such as incomplete sintering of the product and unstable structure may occur.

[0064] Then introduce a protective gas. The protective gas can be a mixed gas of nitrogen and hydrogen, or a mixed gas of argon and hydrogen, or hydrogen, or ammonia decomposition gas. Introducing the above protective gas as a protective atmosphere can prevent the friction particle blank from being oxidized in the high-temperature sintering environment, ensure that the friction particle blank undergoes a sintering reaction in a pure environment, and guarantee the product quality. The heating element in the sintering furnace adopts a sintering structure with a ceramic rod wound with a high-temperature alloy wire, and ensure that its heating rate is less than or equal to 2°C per minute. Controlling the heating rate within this range can protect other devices and extend the service life of the furnace, ensure small furnace temperature fluctuations and uniform heating, and guarantee the sintering quality. Thus, when the temperature of each part in the sintering furnace rises to the set temperature of that part, start placing the product on the conveyor belt 31 for sintering.

[0065] Since the material of the green compact 22 is composed of multiple materials with different coefficients of thermal expansion, if a linear rapid heating method is adopted, due to the too large difference in the expansion degrees of different materials, stress is likely to be generated inside the blank, resulting in poor sintering quality of the product. Therefore, a segmented stepped heating method is adopted during sintering. By setting each heating section with specific length and temperature parameters, the above problems can be effectively solved. Among them, the lengths of the first preset length, the second preset length, the third preset length, the fourth preset length, and the fifth preset length are all 1000 mm - 1400 mm, that is, they can be 1000 mm, 1100 mm, 1200 mm, 1300 mm, or 1400 mm, or other length values within this range. Such a setting can ensure that the product can be kept warm for enough time when passing through this section at a fixed speed, the product can be sintered through without overheating, and the sintering efficiency can be improved.

[0066] As a possible implementation, as Figure 4 shown, the sintered friction particles 2 are cooled to obtain the formed pearlite structure friction particle finished product, including: cooling the friction particles 2 by using a circulating water cooling jacket 32 and an inert gas air cooling method to obtain the formed pearlite structure friction particle finished product.

[0067] In the sintering process of the present invention, after the friction particles 2 are sintered, they need to be cooled to obtain the formed pearlite structure friction particle finished product. The specific cooling method adopted is the combination of a circulating water cooling jacket 32 and an inert gas air cooling. During the cooling process, the circulating water cooling jacket 32 plays a key role. In the cooling section, the outside of the product is surrounded by the circulating water jacket, and the water flowing inside the circulating water jacket can quickly take away the heat radiated by the product during cooling, promoting the rapid decrease of the product temperature. At the same time, for the product at the wrapped part of the circulating water jacket in the cooling section, an inert gas air cooling method is used for auxiliary cooling. The inert gas air cooling and the circulating water cooling jacket 32 cooperate with each other and act synergistically from the inside and outside of the product, enabling rapid and uniform cooling of the sintered friction particles 2 to obtain the required pearlite structure. This combined cooling method effectively avoids problems such as stress generation or performance change inside the product caused by uneven cooling, ensuring the stable quality of the finally formed pearlite structure friction particle finished product.

[0068] In the description of the above embodiments, specific features, structures, materials, or characteristics can be combined in a suitable manner in any one or more embodiments or examples.

[0069] As described above, it is only the specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention can easily think of changes or substitutions, which should all be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims described above.

Claims

1. A friction particle-assisted sintering tooling, characterized in that It includes a top plate, a bottom plate and at least two opposite side plates; both ends of the side plates are respectively connected to the top plate and the bottom plate, and enclose at least one limiting cavity for accommodating friction particles, and the height of the limiting cavity is the same as the height of the friction particles to be sintered; there is a lateral opening between the side plates for taking and placing the friction particles; the top plate and the bottom plate vertically limit the upper and lower surfaces of the friction particles respectively, and the side plates horizontally limit the side surfaces of the friction particles.

2. The friction particle-assisted sintering tooling according to claim 1, wherein, The number of the side plates is two, and they are arranged in parallel on the bottom plate. The two side plates, the top plate and the bottom plate enclose a strip-shaped limiting cavity with openings on both sides.

3. The friction particle-assisted sintering tooling according to claim 1, wherein The materials of the top plate, the bottom plate and the side plates are graphite or graphite composite materials.

4. The friction particle-assisted sintering tooling according to claim 1, characterized in that, There are horizontally extending supporting steps on the inner surfaces of at least two opposite side plates, and the supporting steps are used to support the skeleton of the friction particles.

5. The friction particle-assisted sintering tooling according to any one of claims 1-4, characterized in that, The top plate, the side plates and the bottom plate are of an integrally formed structure.

6. A friction particle sintering device, characterized in that, It includes: A chain belt type sintering furnace for sintering and forming friction particles; The friction particle auxiliary sintering tooling as described in any one of claims 1-5, and the friction particle auxiliary sintering tooling is arranged on the chain belt of the chain belt type sintering furnace and is synchronously conveyed along with the movement of the chain belt.

7. A friction particle sintering process, characterized in that, Using the friction particle sintering equipment as described in claim 6, the friction particle sintering process includes: Fixing the green compact and the skeleton to form a friction particle blank; Putting the friction particle blank into the limiting cavity of the friction particle auxiliary sintering tooling; Placing the friction particle auxiliary sintering tooling on the chain belt of the chain belt type sintering furnace and sintering the friction particle blank under the protection of a protective gas; Cooling the sintered friction particles to obtain a formed friction particle finished product with a pearlite structure.

8. The sintering process according to claim 7, characterized in that, Putting the friction particle blank into the limiting cavity of the friction particle auxiliary sintering tooling includes: putting the friction particle blank into the limiting cavity of the friction particle auxiliary sintering tooling with the skeleton located below and the green compact located above.

9. The sintering process according to claim 7, characterized in that, Placing the friction particle auxiliary sintering tooling on the chain belt of the chain belt type sintering furnace and sintering the friction particle blank under the protection of a protective gas includes: Introducing a protective gas into the chain belt type sintering furnace as a protective atmosphere; Placing the friction particle auxiliary sintering tooling on the chain belt of the chain belt type sintering furnace; Driving the tooling to move in the chain belt type sintering furnace by the chain belt of the chain belt type sintering furnace and performing segmented step heating; wherein, the running speed of the chain belt is 25mm / min - 35mm / min, and the segmented step heating includes: Heat in the first heating section with a length of the first preset length, and the heating temperature is 80°C - 100°C; heat in the second heating section with a length of the second preset length, and the heating temperature is 100°C - 300°C; heat in the third heating section with a length of the third preset length, and the heating temperature is 300°C - 500°C; heat in the fourth heating section with a length of the fourth preset length, and the heating temperature is 500°C - 700°C; heat in the fifth heating section with a length of the fifth preset length, and the heating temperature is 700°C - 900°C; heat in the sixth heating section with a length of the sixth preset length, and the heating temperature is 900°C - 1100°C.

10. The friction particle sintering process according to claim 7, wherein, Cool the sintered friction particles to obtain the finished product of pearlite structure friction particles, including: cooling the friction particles by using a circulating water cooling jacket and inert gas air cooling to obtain the finished product of the pearlite structure friction particles.

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