Method for manufacturing synchronous pulley

Abstract

The invention provides a manufacturing method of a synchronous pulley. The synchronous pulley is provided with a hub, a flange and a rim. The manufacturing method comprises the following steps that a main body casting step is conducted, specifically, a titanium alloy containing 5.2%-5.7% by mass of Al and 3.5%-4% by mass of V is used for casting a main body part of the synchronous belt wheel, and the main body part comprises a hub and a flange; and in the 3D printing step, a rim is printed and manufactured on the outer edge of the hub of the main body part obtained in the main body casting step, and in the 3D printing step, titanium alloy powder containing, by mass, 5.0%-5.4% of Al and 3%-3.5% of V is adopted. According to the method, the rim can be simply and quickly combined and arranged on the radial outer edge of the hub at low cost through 3D printing, and the synchronous pulley made of the titanium alloy material is obtained. And moreover, the titanium alloy powder and the base material titanium alloy of the main body part have good metallurgical bonding property and similar physical properties, so that the bonding strength between the rim and the main body part can be effectively improved, and the residual stress can be reduced.

Description

Technical Field

[0001] The invention relates to the field of synchronous pulley manufacturing, and in particular to a method for manufacturing a synchronous pulley. Background Art

[0002] Synchronous pulleys are common components in mechanical transmission and are widely used in various fields. For different application scenarios, synchronous pulleys have corresponding customized requirements. For example, in application scenarios where synchronous pulleys are required to have high strength, corrosion resistance and light weight, synchronous pulleys made of titanium alloy are required.

[0003] However, in the prior art, synchronous pulleys are generally made of raw materials through cutting. When titanium alloys are processed, especially when titanium alloys are used to process synchronous pulleys with arc-shaped teeth and flanges, there are the following difficulties: 1. Titanium alloys are highly chemically active and are easily combined with gas impurities (oxygen, nitrogen, and hydrogen, etc.) at high temperatures. After titanium is oxidized, a brittle layer is formed, which leads to hardening of the workpiece surface, making the processing more difficult and prone to chipping. 2. The thermal conductivity of titanium alloys themselves is extremely low, so the heat generated during the cutting process is not easy to dissipate, but is concentrated in the cutting area, causing rapid wear and cracking of the tool, and chip accumulation, shortening the tool life. 3. Titanium alloys have small elastic abrasives, and are prone to built-up edge during cutting, leading to tool sticking. 4. Milling of titanium alloy products is more difficult because milling is intermittent cutting, and it is easy for chips to stick to the blade. When the chip-sticking tool cuts into the workpiece again, the chip sticking is knocked off and a small piece of the tool material is taken away, resulting in chipping. In addition, the ribs will affect the cutting angle of the blade during cutting, further restricting the processing of arc-shaped teeth and affecting the processing efficiency.

[0004] In summary, when the raw material is titanium alloy, it is difficult to ensure the accuracy of the rim formed by cutting in the synchronous pulley through cutting. When the rim accuracy is low, it is difficult to mesh with the synchronous belt for transmission. At the same time, the process of manufacturing synchronous pulleys only through cutting is complicated and costly. Therefore, it is difficult to quickly and cost-effectively produce titanium alloy synchronous pulleys that meet actual application needs through conventional cutting. Summary of the invention

[0005] In view of the above problems, the present invention provides a method for manufacturing a synchronous pulley, by casting a titanium alloy material with a specific Al and V ratio to obtain a main body including a hub and a rib, and combining the rim into the hub through 3D printing of titanium alloy powder with a specific Al and V ratio. A titanium alloy synchronous pulley with high integrity can be manufactured quickly and at low cost, and both the geometric accuracy of the rim and the bonding strength with the main body can be ensured.

[0006] The present invention provides a manufacturing method of a synchronous pulley, wherein the synchronous pulley comprises a wheel hub, a rib and a rim, wherein the ribs are arranged at both axial ends of the wheel hub and extend outward in a radial direction, and the rim is arranged at the radial outer edge of the wheel hub, and the rim is a circular arc tooth;

[0007] The manufacturing method comprises the following steps:

[0008] The main body casting step uses a titanium alloy containing 5.2% to 5.7% Al and 3.5% to 4% V by mass to cast the main body of the synchronous pulley, wherein the main body includes a hub and a flange;

[0009] The 3D printing step is to print and manufacture the rim at the outer edge of the hub of the main body obtained in the main casting step. In the 3D printing step, the titanium alloy powder used is a titanium alloy powder containing 5.0% to 5.4% Al by mass and 3% to 3.5% V by mass.

[0010] According to the above technical solution, the wheel rim can be stably combined with the radial outer edge of the hub in the main body simply, quickly and at low cost through 3D printing to obtain a synchronous pulley made of titanium alloy.

[0011] Moreover, the titanium alloy powder used in the 3D printed wheel rim has good metallurgical bonding with the titanium alloy used in the cast main body, which can effectively improve the bonding strength between the wheel rim and the main body. Through 3D printing, the wheel rim can be seamlessly bonded to the radial outer edge of the hub, ensuring the integrity of the synchronous pulley and thus ensuring the stability of the synchronous pulley during use. In addition, the titanium alloy powder used in the 3D printed wheel rim has similar physical properties to the base titanium alloy of the cast main body, such as thermal expansion coefficient and melting point, which can effectively reduce residual stress.

[0012] Optionally, the titanium alloy powder is spherical particles, and the particle size of the titanium alloy powder is 10 μm-65 μm.

[0013] According to the above technical solution, the titanium alloy powder of the present invention has good fluidity and can be evenly spread during the printing process, thereby ensuring the density and surface quality of the printed wheel rim.

[0014] Optionally, the 3D printing step is implemented using a powder bed fusion method. In the 3D printing step, the laser power is set to 220W-250W, and the scanning speed is 50mm / s-70mm / s.

[0015] According to the above technical solution, the depth of the welding pool can be effectively increased, and the bonding force between the arc-shaped teeth and the main body can be improved, so that the arc-shaped teeth can be stably combined and arranged in the main body.

[0016] Optionally, in the 3D printing step, the scanning path of the laser is to complete the printing of each arc-shaped tooth through a serpentine scanning path.

[0017] According to the above technical solution, a continuous molten pool can be formed through the serpentine scanning path, which reduces the generation of unfused and pores and improves the compactness of the arc-shaped teeth. At the same time, it can disperse thermal stress and reduce the deformation of the arc-shaped teeth. In addition, it can effectively utilize laser energy and improve printing efficiency.

[0018] Optionally, before the 3D printing step and after the main body casting step, a grinding step is also included to grind the outer edge of the hub.

[0019] According to the above technical solution, it is convenient to spread powder after grinding, and at the same time, diffuse reflection can be formed during laser irradiation to facilitate the melting of printing powder, and the bonding force can be improved, so that the printed rim is stably connected to the main body.

[0020] Optionally, after the 3D printing step, a post-processing step is also included, in which the synchronous pulley is subjected to hot isostatic pressing. During the hot isostatic pressing process, the temperature is 900°C±10°C, the pressure is 100MPa±10MPa, and the time is 2h-3h.

[0021] According to the above technical solution, by performing hot isostatic pressing treatment, the holes and defects inside the rim formed by 3D printing can be eliminated, thereby improving the density while improving the ductility and fatigue resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic structural diagram of a synchronous pulley in an embodiment of the present invention;

[0023] Figure 2 This is a flowchart of a method for manufacturing a timing pulley according to an embodiment of the present invention.

[0024] Reference numerals: wheel hub 10 ; flange 20 ; rim 30 . DETAILED DESCRIPTION

[0025] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0026] refer to Figure 1 The synchronous pulley of this embodiment has a hub 10, a rib 20 and a rim 30. The rib 20 is arranged at both axial ends of the hub 10 and extends outward in the radial direction. The rim 30 is arranged at the radial outer edge of the hub 10, and the rim 30 is an arc-shaped tooth.

[0027] refer to Figure 2 A method for manufacturing a synchronous pulley in this embodiment comprises the following steps:

[0028] S1: a main body casting step, using a titanium alloy containing 5.2% to 5.7% by mass of Al and 3.5% to 4% by mass of V to cast the main body of the synchronous pulley, the main body including a hub 10 and a flange 20 .

[0029] The casting of the main body may include the following process: melting the Ti ingot in a vacuum arc furnace, adding alloy elements for refining, and controlling the temperature to be slightly higher than the liquidus line of the titanium alloy. Then, under vacuum conditions, the molten titanium alloy is poured into a ceramic mold to obtain a main body of the synchronous pulley of a suitable shape.

[0030] In the prior art, the flange 20 is generally manufactured separately from the wheel hub 10, and the flange 20 is installed on the axial ends of the wheel hub 10 by spinning or other processes. There is a risk of the flange 20 being separated from the wheel hub 10 during the contact correction process. In this embodiment, by casting the wheel hub 10 and the flange 20 into an integrally formed main body, the flange 20 can be effectively prevented from being separated from the wheel hub 10 during the contact correction process.

[0031] After the main body casting step, a grinding step is also included to grind the outer edge of the wheel hub 10 .

[0032] Specifically, the outer edge of the hub 10 and the inner side of the rib 20 are polished to facilitate powder spreading, and diffuse reflection can be formed during laser irradiation to facilitate melting of the printed powder, while also improving the bonding strength to facilitate the subsequent stable connection of the printed rim 30 to the main body.

[0033] After the main casting step S1, perform S2: 3D printing step, in which a rim is printed at the outer edge of the hub of the main body obtained in the main casting step S1. In the 3D printing step, the titanium alloy powder used is a titanium alloy powder containing 5.0% to 5.4% Al by mass and 3% to 3.5% V by mass.

[0034] Specifically, the titanium alloy powder is spherical particles with a particle size of 10 μm-65 μm. It has good fluidity and can be evenly spread during the printing process, thereby ensuring the density and surface quality of the printed arc-shaped teeth.

[0035] In this embodiment, a powder bed fusion method is used for 3D printing, and the specific process is as follows:

[0036] First, a three-dimensional structure of multiple rims 30 arranged around the radial outer edge of the hub 10 is constructed using the Pre / Engineer software, the three-dimensional structure is converted into an STL format file, and sliced ​​to obtain multi-layer two-dimensional slices formed by stacking. Each layer of the two-dimensional slice has data information of the processing surface of that layer, and the corresponding two-dimensional slice is input into the 3D printing device.

[0037] Then, the rib 20 at one end of the hub 10 is placed horizontally in the base of the 3D printing device with the main body placed vertically, and titanium alloy powder is evenly laid on the circular plane surrounding the rib 20 and the outer edge of the hub 10. The 3D printing device prints a two-dimensional plane by laser melting the powder according to the processing surface data information in each layer of the two-dimensional slice. After each printing is completed, powder is re-laid on the original powder until the printing is completed. After the printing is completed, a synchronous pulley is obtained, and the radial outer edge of the hub 10 of the synchronous pulley is provided with a rim 30 with arc-shaped teeth.

[0038] In this embodiment, the rim 30 can be simply, quickly and cost-effectively combined and stably arranged on the radial outer edge of the hub 10 by 3D printing. At the same time, in the 3D printing process, multiple rims 30 can be printed simultaneously by multiple laser devices according to the number of rims 30 to be arranged, thereby improving manufacturing efficiency.

[0039] In addition, the titanium alloy powder containing 5.0% to 5.4% Al and 3% to 3.5% V by mass used in the 3D printed rim 30 has good metallurgical bonding with the titanium alloy containing 5.2% to 5.7% Al and 3.5% to 4% V by mass used in the main body casting, and the rim 30 can be seamlessly bonded to the radial outer edge of the hub 10 through 3D printing. At the same time, the axial ends of the rim 30 can also be combined with the flange 20, further improving the integrity of the synchronous pulley and ensuring the stability of the synchronous pulley during use.

[0040] It should be noted that the powder bed fusion method is only exemplary. In other embodiments of the present invention, laser cladding (Laser Cladding) / laser additive manufacturing (DED, Directed Energy Deposition), electron beam fuse additive manufacturing (EBAM, Electron Beam Additive Manufacturing), selective laser melting (SLM, Selective Laser Melting), cold spraying (Cold Spray) and the like can also be used to produce the arc-shaped rim 30 on the outer edge of the hub 10, and the present invention is not limited to this.

[0041] In addition, the titanium alloy powder used in the 3D printed rim 30 has similar physical properties as the cast base titanium alloy of the main body, such as thermal expansion coefficient and melting point, which can effectively reduce residual stress. At the same time, the rim 30 is made of titanium alloy powder containing 5.0% to 5.4% Al by mass and 3% to 3.5% V by mass, which can improve the geometric accuracy of the rim 30 and make it easier to obtain a synchronous pulley with a surface roughness that meets the customized requirements.

[0042] In the 3D printing step, the laser power is set to 220W-250W, and the scanning speed is 50mm / s-70mm / s, which can effectively increase the depth of the weld pool, increase the bonding force between the arc-shaped teeth and the main body, and make the arc-shaped teeth stably combined and set in the main body.

[0043] In the 3D printing step, the scanning path of the laser is to complete the printing of each arc-shaped tooth through a serpentine scanning path. The serpentine scanning path can form a continuous molten pool, reduce the generation of unfused and pores, improve the density of the arc-shaped teeth, and at the same time disperse the thermal stress and reduce the deformation of the arc-shaped teeth. In addition, the laser energy can be effectively utilized to improve the printing efficiency. It should be noted that the serpentine scanning path is preferred, but is not limited to this. In other embodiments of the present invention, linear scanning, chessboard scanning, spiral scanning, cross scanning or any other suitable scanning method may also be used.

[0044] After the 3D printing step, a post-processing step is also included, in which the synchronous pulley obtained after 3D printing is subjected to hot isostatic pressing. During the hot isostatic pressing process, the temperature is 900°C±10°C, the pressure is 100MPa±10MPa, and the time is 2h-3h.

[0045] In this embodiment, by performing hot isostatic pressing on the synchronous pulley obtained by 3D printing, the holes and defects formed inside the material due to 3D printing can be eliminated under high temperature and high pressure conditions, thereby improving the density of the material while improving the ductility and fatigue resistance.

[0046] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for manufacturing a synchronous pulley, characterized in that: The synchronous pulley has a hub, a rib and a rim, wherein the ribs are arranged at both axial ends of the hub and extend outward in the radial direction, and the rim is arranged at the radial outer edge of the hub, and the rim is an arc-shaped tooth; The manufacturing method comprises the following steps: A main body casting step, using a titanium alloy containing 5.2% to 5.7% by mass of Al and 3.5% to 4% by mass of V to cast the main body of the synchronous pulley, wherein the main body includes the hub and the rib; A 3D printing step is performed to print and manufacture the wheel rim at the outer edge of the hub of the main body portion obtained in the main body casting step. In the 3D printing step, the titanium alloy powder used is a titanium alloy powder containing 5.0% to 5.4% Al by mass and 3% to 3.5% V by mass.

2. The method for manufacturing a synchronous pulley according to claim 1, characterized in that: The titanium alloy powder is spherical particles, and the particle size of the titanium alloy powder is 10 μm-65 μm.

3. The method for manufacturing a synchronous pulley according to claim 1, characterized in that: The 3D printing step is implemented by a powder bed fusion method. In the 3D printing step, the laser power is set to 220W-250W, and the scanning speed is 50mm / s-70mm / s.

4. The method for manufacturing a synchronous pulley according to claim 3, characterized in that: In the 3D printing step, the scanning path of the laser is to complete the printing of each arc-shaped tooth through a serpentine scanning path.

5. The method for manufacturing a synchronous pulley according to claim 1, characterized in that: Before the 3D printing step and after the main body casting step, a grinding step is also included to grind the outer edge of the hub.

6. The method for manufacturing a synchronous pulley according to claim 1, characterized in that: After the 3D printing step, a post-processing step is also included, in which the synchronous pulley is subjected to hot isostatic pressing. During the hot isostatic pressing process, the temperature is 900°C±10°C, the pressure is 100MPa±10MPa, and the time is 2h-3h.

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