A method of forming a carbon fiber stepped shaft
By preparing the carbon fiber stepped shaft sand core through a sand core mold and laying carbon fiber prepreg cloth, the carbon fiber stepped shaft is formed in one piece, which solves the problem of metal connecting parts affecting strength and weight and improves the integrity and strength.
Patent Information
- Application Number
- CN202411449849.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-16
- Publication Date
- 2025-10-24
- Estimated Expiration
- 2044-10-16
AI Technical Summary
In the prior art, carbon fiber stepped shafts are assembled through metal connectors, which affects strength and integrity, and is also heavy and cannot meet the needs of large-scale mechanical equipment.
A sand core mold is used to prepare a stepped shaft sand core, and carbon fiber prepreg is laid on the outside of the sand core. An integrated preformed stepped shaft is formed through pressure-maintaining and curing. The formed stepped shaft is obtained after demoulding, avoiding metal connectors.
The integrity and overall strength of the carbon fiber stepped shaft are improved, the weight is reduced, and the needs of large-scale mechanical equipment are met.
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Figure CN119348178B_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of shaft forming, in particular to a forming method of carbon fiber stepped shaft. BACKGROUND
[0002] The shaft is a mechanical part for supporting, rotating and transmitting power, etc., and is commonly used in the fields of mechanical equipment, automobiles, motor vehicles and ships; the metal shaft generally has a high weight due to the high density of metal material, which leads to an excessive mass of the equipment, and greatly reduces the service life of the metal shaft in high temperature and high humidity environments; the carbon fiber shaft is increasingly widely applied in the field of engineering machinery technology due to its high strength, light weight, good wear resistance, corrosion resistance and fatigue resistance.
[0003] At present, the carbon fiber stepped shafts with different cross-sectional sizes are mostly assembled by a plurality of carbon fiber shafts with different cross-sectional sizes through metal connecting pieces, and the assembly must be machined and punched, which not only affects the strength of the original carbon fiber shaft, but also reduces the overall integrity of the stepped shaft after assembly and increases the quality, which is relatively energy-consuming for some large mechanical equipment. SUMMARY
[0004] The purpose of the present application is to provide a forming method of carbon fiber stepped shaft to solve the problems existing in the prior art, improve the overall integrity and overall strength of the carbon fiber stepped shaft, and reduce the overall weight.
[0005] To achieve the above purpose, the present application provides the following solutions:
[0006] The present application provides a forming method of carbon fiber stepped shaft, comprising the following steps:
[0007] Preparation of stepped shaft sand core: forming and demolding in the sand core mold to obtain the stepped shaft sand core;
[0008] Preforming: applying carbon fiber prepreg on the outer wall of the stepped shaft sand core and performing pressure holding and curing to obtain a preformed stepped shaft;
[0009] Demolding forming: demolding the preformed stepped shaft from the stepped shaft sand core to obtain a formed stepped shaft.
[0010] Preferably, in the step of preparing the stepped shaft sand core, the sand core mold has a plurality of sand core cavities in the axial direction, adjacent sand core cavities have different cross-sectional sizes, the sand core cavities are filled with precast sand cores, and the sand core mold filled with the precast sand cores is cured, then demolded and polished to obtain the stepped shaft sand core.
[0011] Preferably, in the step of preparing the stepped shaft sand core, the sand core mold is detachably connected between the adjacent sand core cavities, and each sand core cavity comprises a plurality of circumferentially detachable sub-cavities; and the sand core mold is detachably provided with a cover at both ends.
[0012] Preferably, in the step of preparing the stepped shaft sand core, release cloth is laid on the inner wall of each sand core cavity, and the preformed sand core is sequentially filled and tamped in each sand core cavity, and a core shaft is coaxially arranged in the sand core mold to fix the preformed sand core in each sand core cavity; the sand core mold filled with the preformed sand core is cured, and then the sand core mold is removed for demolding and polishing of the preformed sand core, thereby obtaining the stepped shaft sand core.
[0013] Preferably, in the step of preforming, inner release cloth is first laid on the outer periphery of the stepped shaft sand core, and then the carbon fiber prepreg is laid and stacked on the outer periphery of the inner release cloth, and outer release cloth is laid on the outer periphery of the carbon fiber prepreg, and overall pressure holding curing is performed to obtain the preformed stepped shaft.
[0014] Preferably, in the step of preforming, the carbon fiber prepreg is laid on each shaft shoulder and each shaft body of the stepped shaft sand core, and the carbon fiber prepreg laid on the shaft shoulder is provided with a circumferential lap joint portion on the outer circle and the inner circle, which is used for lap joint with the carbon fiber prepreg laid on the outer shaft body.
[0015] Preferably, the circumferential lap joint portion comprises a plurality of circumferentially distributed sawtooth portions, each of which is used for lap joint with the carbon fiber prepreg laid on the outer shaft body.
[0016] Preferably, in the step of preforming, a plurality of layers of carbon fiber prepreg are laid on the outer periphery of the stepped shaft sand core, and the circumferential lap joint portions on each shaft shoulder are sequentially lap jointed with the carbon fiber prepreg laid on the outer shaft body; and the circumferential lap joint portions between adjacent two layers are staggered.
[0017] Preferably, in the step of preforming, vacuum bag is used for vacuum pressure holding.
[0018] Preferably, the preformed sand core adopts water-soluble sand core; in the step of demolding and forming, the stepped shaft sand core with the preformed stepped shaft is soaked in water, and the stepped shaft sand core is washed away by water flow, so that the preformed stepped shaft is demolded, and the formed stepped shaft is obtained after processing.
[0019] The present application has the following technical effects compared with the prior art:
[0020] The forming method of the carbon fiber stepped shaft provided by the application first prepares a stepped shaft sand core through a sand core mold, then lays carbon fiber prepreg outside the stepped shaft sand core, and obtains an integrated preformed stepped shaft after pressure curing, and then demolds the preformed stepped shaft to obtain a formed stepped shaft, so that the carbon fiber stepped shaft is integrally formed, does not need to be assembled by metal connecting pieces, improves the integrity and overall strength of the carbon fiber stepped shaft, and can reduce the overall weight. BRIEF DESCRIPTION OF DRAWINGS
[0021] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.
[0022] Figure 1 The structural schematic diagram of the sand core mold provided for the first embodiment is shown in the figure.
[0023] Figure 2 The structural schematic diagram of the stepped shaft sand core provided for the first embodiment is shown in the figure.
[0024] Figure 3 The structural schematic diagram of the pressure roller table provided for the first embodiment is shown in the figure.
[0025] Figure 4 The carbon fiber prepreg laying corresponding diagram at the shaft shoulder provided for the first embodiment is shown in the figure.
[0026] In the figure: 1-sand core mold; 11-sand core cavity; 12-sub cavity; 13-closure; 14-core shaft; 2-stepped shaft sand core; 21-shaft shoulder; 22-shaft body; 3-carbon fiber prepreg; 31-circumferential lap joint part; 32-sawtooth part; 4-pressure roller table; 41-step. DETAILED DESCRIPTION
[0027] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some embodiments of the present application, not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.
[0028] The purpose of the present application is to provide a forming method of a carbon fiber stepped shaft to solve the problems in the prior art, improve the integrity and overall strength of the carbon fiber stepped shaft, and reduce the overall weight.
[0029] In order to make the above objectives, characteristics and advantages of the present application more obvious and easy to understand, the present application will be further described in detail below with reference to the drawings and specific embodiments.
[0030] Embodiment one
[0031] The embodiment provides a forming method of a carbon fiber stepped shaft, comprising the following steps:
[0032] Preparation of the stepped shaft sand core: forming the stepped shaft sand core 2 by demolding in the sand core mold 1;
[0033] Preforming: laying the carbon fiber prepreg 3 on the outer wall of the stepped shaft sand core 2 and performing pressure holding and curing to obtain a preformed stepped shaft;
[0034] Demolding forming: demolding the preformed stepped shaft from the stepped shaft sand core 2 to obtain a formed stepped shaft.
[0035] In the embodiment, the stepped shaft sand core 2 is prepared by the sand core mold 1, then the carbon fiber prepreg 3 is laid on the outer wall of the stepped shaft sand core 2, and an integrated preformed stepped shaft is obtained after pressure holding and curing, and then the preformed stepped shaft is demolded to obtain a formed stepped shaft, so that the carbon fiber stepped shaft is integrally formed without the need for metal connecting pieces to be assembled, the integrity and overall strength of the carbon fiber stepped shaft are improved, and the overall weight is reduced.
[0036] In an optional solution of the embodiment, preferably, referring to Figure 1 , in the step of preparing the stepped shaft sand core, the sand core mold 1 has a plurality of sand core cavities 11 in the axial direction, adjacent sand core cavities 11 have different cross-sectional sizes, the sand core cavities 11 are filled with preformed sand cores, and the sand core mold 1 filled with the preformed sand cores is cured, then demolded and polished to obtain the stepped shaft sand core 2, as shown in Figure 2 ; wherein the number and inner diameter of the sand core cavities 11 of the sand core mold 1 are determined according to the size of the formed stepped shaft, the number of the sand core cavities 11 should be the same as the number of stepped sections of the formed stepped shaft, and the inner diameter of the sand core cavities 11 should be smaller than the corresponding size of the formed stepped shaft, so that the required size of the carbon fiber stepped shaft is achieved after laying the carbon fiber prepreg 3.
[0037] In an optional solution of the embodiment, preferably, in the step of preparing the stepped shaft sand core, the sand core mold 1 is detachably connected between adjacent sand core cavities 11, and each sand core cavity 11 comprises a plurality of sub-cavities 12 which are detachably connected in the circumferential direction; and the sand core mold 1 is detachably provided with a cover 13 at both ends; adjacent sub-cavities 12 and adjacent sand core cavities 11 are detachably connected by bolts, so as to facilitate demolding.
[0038] In the optional scheme of the embodiment, preferably, in the step of preparing the stepped shaft sand core, a release cloth is laid on the inner wall of each sand core cavity 11, and each sand core cavity 11 is sequentially filled with and tamped with the prefabricated sand core, and the sand core mold 1 is coaxially provided with a core shaft 14 fixedly penetrating the prefabricated sand core in each sand core cavity 11; the sand core mold 1 filled with the prefabricated sand core is cured, and then the sand core mold 1 is disassembled to release the mold and polish the prefabricated sand core, thereby obtaining the stepped shaft sand core 2.
[0039] The release cloth is laid to facilitate the subsequent release of the prefabricated stepped shaft sand core 2. First, a layer of release cloth is attached inside each sub-cavity 12 of each sand core cavity 11, and then one side cover 13 is assembled with one side of the sand core cavity 11 by means of bolts, the core shaft 14 and the cover 13 are connected by means of bolts, the prepared prefabricated sand core is filled into the sand core cavity 11 and tamped, and then the other sand core cavities 11 are sequentially assembled and filled with the prepared prefabricated sand core into the sand core cavities 11 and tamped; finally, the other cover 13 is assembled; then the sand core mold 1 filled with the prefabricated sand core is placed in a curing oven for curing, and cured at 150°C for 20h, and then the sand core mold 1 is disassembled to obtain the stepped shaft sand core 2. The surface of the stepped shaft sand core 2 is polished and finished to be flat, as shown in Figure 2 The core shaft 14 can increase the fracture strength of the stepped shaft sand core 2, and also facilitates handling.
[0040] In the optional scheme of the embodiment, preferably, in the step of preforming, first, an inner release cloth is laid on the outer periphery of the stepped shaft sand core 2, then carbon fiber prepreg cloth 3 is laid and laid on the outer periphery of the inner release cloth, and an outer release cloth is laid on the outer periphery of the carbon fiber prepreg cloth 3, and the whole is cured under pressure to obtain a preformed stepped shaft; the inner release cloth and the outer release cloth are laid to facilitate the subsequent release of the carbon fiber prepreg cloth 3, and to avoid the prefabricated sand core affecting the forming surface quality of the carbon fiber prepreg cloth 3.
[0041] In the optional scheme of the embodiment, preferably, as shown in Figure 4 In the step of preforming, carbon fiber prepreg cloth 3 is laid on each shoulder 21 and each shaft body 22 of the stepped shaft sand core 2, respectively. The outer circle and the inner circle of the carbon fiber prepreg cloth 3 laid on the shoulder 21 are both provided with a circumferential lap joint part 31, which is used to lap with the carbon fiber prepreg cloth 3 laid on the outer periphery of the adjacent shaft body 22. By laying and fixing the carbon fiber prepreg cloth 3 on the shoulder 21 and each shaft body 22, respectively, the laying quality of the carbon fiber prepreg cloth 3 at the outer circle and the inner circle of the shoulder 21 can be controlled, and excessive accumulation can be avoided.
[0042] In an optional solution of the embodiment, preferably, the carbon fiber prepreg 3 at the outer circle and inner circle of the shaft shoulder 21 needs to be considered to be overlapped with the two adjacent shaft bodies 22 during the laying-up, not only needs to have sufficient connection strength, but also needs to avoid wrinkling during the laying-up, and prevent local accumulation from being too concentrated, therefore the circumferential overlapping part 31 includes a plurality of circumferentially distributed sawtooth parts 32, each sawtooth part 32 is used to overlap the carbon fiber prepreg 3 laid on the outer surface of the adjacent shaft body 22, the sawtooth part 32 has the advantage that the shaft shoulder 21 has the largest overlapping area at the connection with the shaft body 22, and as the overlapping position of the carbon fiber prepreg 3 on the shaft shoulder 21 and the shaft body 22 changes, the overlapping area can be reduced, so that the local accumulation degree at the overlapping part can be effectively reduced.
[0043] In an optional solution of the embodiment, preferably, in the step of preforming, the stepped shaft sand core 2 is laid with multiple layers of carbon fiber prepreg 3, the circumferential overlapping part 31 at each shaft shoulder 21 is sequentially overlapped with the carbon fiber prepreg 3 laid on the outer surface of the adjacent shaft body 22, and the sequential overlapping improves the connection strength; in order to reduce the local accumulation degree at the overlapping part of the shaft body 22 and the shaft shoulder 21, the circumferential overlapping parts 31 between the adjacent two layers are staggered, that is, each time the shaft shoulder 21 is laid, the position of the last time the shaft shoulder 21 is laid is rotated by half the angle of the sawtooth part 32 and then laid, so that the circumferential overlapping part is closed while reducing the local accumulation. Each time a layer of carbon fiber prepreg 3 is laid, the pores and bubbles in the carbon fiber prepreg 3 are scraped out with a scraping block.
[0044] Before laying the carbon fiber prepreg 3, the shape and size of the carbon fiber prepreg 3 are cut according to the required size, it needs to be noted that as the laying thickness increases, the laying size of the shaft shoulder 21 changes, and the carbon fiber prepreg 3 needs to be adaptively adjusted when cutting; after the carbon fiber prepreg 3 is laid, the pressure roller table 4 is used for pressing, please refer to Figure 3 The pressure roller table 4 rolls the preformed stepped shaft through the upper and lower plates, and the pressure roller table 4 is provided with multiple steps 41 matched with the preformed stepped shaft.
[0045] In an optional solution of the embodiment, preferably, in the step of preforming, the vacuum bag is used for vacuumizing and pressure preserving, the vacuum bag is sealed with sealing tape, the un-solidified carbon fiber stepped shaft is put into the vacuum bag, the carbon fiber stepped shaft is completely wrapped with the outer release cloth, and the vacuumizing and pressure preserving is performed for 30 minutes; then the carbon fiber stepped shaft is continuously pressure preserved and put into a curing oven for curing, the curing process is that the temperature is raised to 80°C for 30 minutes and kept constant for 1 hour, then the temperature is raised to 110°C for 15 minutes and kept constant for 1 hour, and finally the temperature is raised to 135°C for 15 minutes and kept constant for 2 hours; wherein the pressure preserving time and the curing temperature and time can be adjusted according to actual needs.
[0046] In the optional solution of the embodiment, preferably, the prefabricated sand core adopts a conventional water-soluble sand core; in the step of demolding forming, the stepped shaft sand core 2 with the prefabricated stepped shaft is soaked in water, and the stepped shaft sand core 2 is washed away through water flow, so that the prefabricated stepped shaft is demolded and processed to obtain the formed stepped shaft.
[0047] The water-soluble sand core is obtained by weighing 200-mesh quartz sand, chopped glass fiber with a length of 2-3 mm, 200-mesh polyvinyl alcohol powder and water in a proportion of 35:3-5:3:1; the polyvinyl alcohol powder, the quartz sand and the chopped glass fiber are uniformly stirred at low speed by a stirrer, then hot water is poured in and stirred at high speed to form the water-soluble sand core; the water-soluble sand core obtained by other conventional material proportioning can also be used; by selecting the water-soluble sand core, demolding is facilitated; specifically, after the stepped shaft sand core 2 is soaked in hot water for 2 h, the sand core and the inner and outer demolding cloth are washed away by using a high-pressure water gun, the mandrel 14 is taken out, the thickness accumulation of the formed stepped shaft is polished to be uniform, and then the formed stepped shaft is machined according to the predetermined size to obtain the final required formed stepped shaft.
[0048] The principles and implementation manners of the present application are described by using specific examples, and the above embodiment is only used to help understand the method of the present application and its core idea; meanwhile, for those skilled in the art, according to the idea of the present application, the specific implementation manners and application ranges will be changed. In conclusion, the content of the specification should not be understood as a limitation of the present application.
Claims
1. A method of forming a carbon fiber step shaft, the method comprising: The method comprises the following steps: Preparation of stepped shaft sand core: forming a stepped shaft sand core (2) by demolding in a sand core mold (1); Preforming: laying carbon fiber prepreg (3) on each shaft shoulder (21) and each shaft body (22) of the stepped shaft sand core (2), the outer circle and the inner circle of the carbon fiber prepreg (3) laid on the shaft shoulder (21) are provided with a circumferential lap joint (31), the circumferential lap joint (31) comprises a plurality of circumferentially distributed sawtooth portions (32), each sawtooth portion (32) is used for lap joint with the carbon fiber prepreg (3) laid outside the adjacent shaft body (22); a plurality of layers of carbon fiber prepreg (3) are laid outside the stepped shaft sand core (2), the circumferential lap joint (31) at each shaft shoulder (21) and the carbon fiber prepreg (3) laid outside the adjacent shaft body (22) are sequentially lap jointed; and the circumferential lap joints (31) between adjacent two layers are staggered; and preforming a stepped shaft by pressure curing. Demolding forming: demolding the preformed stepped shaft from the stepped shaft sand core (2) to obtain a formed stepped shaft.
2. The method of forming a carbon fiber step shaft according to claim 1, wherein: In the step of preparing the stepped shaft sand core, the sand core mold (1) has a plurality of sand core cavities (11) in the axial direction, adjacent sand core cavities (11) have different cross-sectional dimensions, the sand core cavities (11) are used to fill the preformed sand cores, and the sand core mold (1) filled with the preformed sand cores is cured, then demolded and polished to obtain the stepped shaft sand core (2).
3. The method of forming a carbon fiber step shaft according to claim 2, wherein: In the step of preparing the stepped shaft sand core, the sand core mold (1) is detachably connected between adjacent sand core cavities (11), and each sand core cavity (11) comprises a plurality of sub-cavities (12) which are detachably connected in the circumferential direction; and the sand core mold (1) is detachably provided with a cover (13) at both ends.
4. The method of forming a carbon fiber step shaft according to claim 3, wherein: In the step of preparing the stepped shaft sand core, a demolding cloth is laid on the inner wall of each sand core cavity (11), and the preformed sand cores are sequentially filled and tamped in each sand core cavity (11), and the sand core mold (1) is coaxially provided with a core shaft (14) which penetrates through the preformed sand cores in each sand core cavity (11); the sand core mold (1) filled with the preformed sand cores is cured, then the sand core mold (1) is removed for demolding and polishing of the preformed sand cores, to obtain the stepped shaft sand core (2).
5. The method of forming a carbon fiber step shaft according to claim 1, wherein: In the step of preforming, first, an inner demolding cloth is laid on the outer periphery of the stepped shaft sand core (2), then the carbon fiber prepreg (3) is laid and stacked on the outer periphery of the inner demolding cloth, an outer demolding cloth is laid on the outer periphery of the carbon fiber prepreg (3), and the whole is pressure cured to obtain the preformed stepped shaft.
6. The method of forming a carbon fiber step shaft according to claim 1, wherein: In the step of preforming, vacuum bag is used for vacuum pressure preservation.
7. The method of forming a carbon fiber step shaft according to claim 2, wherein: The preformed sand core adopts water-soluble sand core; in the step of demolding forming, the stepped shaft sand core (2) with the preformed stepped shaft is soaked in water, and the stepped shaft sand core (2) is washed away by water flow, so that the preformed stepped shaft is demolded, and the formed stepped shaft is obtained by processing.
Citation Information
Patent Citations
Stepped core shaft type composite material tower and manufacturing process
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