阅读说明：本技术 基于缠绕成型的复合材料板簧本体的制备方法及板簧本体 (Preparation method of composite material plate spring body based on winding forming and plate spring body ) 是由 董轩诚 于 2021-08-16 设计创作，主要内容包括：本申请提供了一种基于缠绕成型的复合材料板簧本体的制备方法及板簧本体,该包括：将纤维丝穿过基于热固性树脂材料或热塑性树脂材料形成的溶液,以获取经该溶液浸渍的纤维丝；在模具中的与板簧的尺寸匹配的缠绕空间内,缠绕经该溶液浸渍的纤维丝,以形成预成型板簧；缠绕过程中,每缠绕至少一层纤维丝后,在该至少一层纤维丝的表面铺设一层纤维毡,并通过带有倒钩的针头,以拱形的形式将该一层纤维毡中的纤维段的两端嵌入到该至少一层纤维丝中；对该预成型板簧固化,得到复合材料板簧本体。本申请提供的方法能够在控制时间成本和模具损耗成本的基础上,生产出满足性能要求的板簧。(The application provides a preparation method of a composite plate spring body based on winding forming and the plate spring body, which comprises the following steps: passing the filaments through a solution formed on the basis of a thermosetting resin material or a thermoplastic resin material, so as to obtain filaments impregnated with the solution; winding the solution-impregnated fiber filaments in a winding space in a mold matching the size of the plate spring to form a preformed plate spring; in the winding process, after winding at least one layer of fiber filaments, laying a layer of fiber felt on the surface of the at least one layer of fiber filaments, and embedding two ends of a fiber section in the layer of fiber felt into the at least one layer of fiber filaments in an arch form through a barbed needle head; and curing the preformed plate spring to obtain the composite material plate spring body. The method provided by the application can be used for producing the plate spring meeting the performance requirement on the basis of controlling the time cost and the die loss cost.)

1. A preparation method of a composite plate spring body based on winding forming is characterized by comprising the following steps:

passing the filaments through a solution formed on the basis of a thermosetting resin material or a thermoplastic resin material, so as to obtain filaments impregnated with said solution;

winding the solution impregnated fiber filaments in a winding space in a mold matching the size of the leaf spring to form a preformed leaf spring; in the winding process, after winding at least one layer of fiber filaments, laying a layer of fiber felt on the surface of the at least one layer of fiber filaments, and embedding two ends of a fiber section in the layer of fiber felt into the at least one layer of fiber filaments in an arch form through a needle head with a barb;

and curing the preformed plate spring to obtain the composite material plate spring body.

2. The method of claim 1, wherein the length of the fiber segment is determined by the number of layers of the at least one layer of fiber filaments and the diameter of the fiber filaments for each layer of fiber mat in the preformed leaf spring.

3. The method of claim 2, wherein the at least one layer of fiber filaments has a number of winding layers of N, and the fiber filaments have a diameter of M; wherein the length of the fiber segment is greater than or equal to 2M N + L + P, wherein L is proportional to the barb size, P is the offset, and M, N, L, P are all values greater than 0.

4. The method of claim 1, wherein the length of the fiber segment is proportional to the total number of layers of filament windings that have been wound on the die for each layer of fiber mat in the preformed leaf spring.

5. The method according to claim 1, wherein at least one row of the needles having the same size as the winding space is provided in a direction perpendicular to a winding direction of the filament;

wherein, the process of embedding both ends of the fiber segment in the layer of fiber felt into the at least one layer of fiber filaments in an arch shape through a barbed needle comprises the following steps:

repeatedly inserting the needle head into the at least one layer of fiber filaments through the layer of fiber felt until the needle head is positioned at the end position of the at least one layer of fiber filaments when the needle head is positioned above the initial area of the at least one layer of fiber filaments in the winding space by rotating the mold; wherein the needle inserts both ends of the fiber segment into the at least one layer of fiber filaments in an arch form through the barbs during repeated insertion of the at least one layer of fiber filaments.

6. The method of claim 5, wherein said repeatedly inserting said needle through said layer of fiber mat and into said at least one layer of fiber filaments comprises:

and controlling the actual density of the needles inserted into the at least one layer of fiber filaments by controlling the rotating speed of the die.

7. The method of claim 5, wherein the density of the needles inserted into the at least one layer of filaments is in the range of 2 to 200 needles per square centimeter.

8. The method of claim 1, wherein winding the solution-impregnated fiber filaments in a winding space in the mold matching the size of the leaf spring comprises:

and winding the fiber filaments impregnated with the solution in the winding space, and applying tension smaller than a first threshold value and larger than a second threshold value to each fiber filament impregnated with the solution in the winding process, wherein the first threshold value is determined according to the size of the space required when the needle head is inserted into the at least one layer of fiber filaments.

9. The method of claim 8, wherein the first threshold is inversely proportional to an amount of space required for the needle to be inserted into the at least one layer of filaments.

10. The method of claim 1, wherein winding the solution impregnated fiber filaments in a winding space in a mold matching the dimensions of the leaf spring to form a preformed leaf spring comprises:

passing a fiber cloth through the solution to obtain a fiber cloth impregnated with the solution;

laying one or more layers of fiber cloth impregnated with the solution in the winding space;

winding the solution-impregnated fiber filaments in the winding space in which one or more layers of the fiber cloth are laid to form the preformed plate spring.

11. The method of claim 10, wherein said winding of said solution impregnated fiber filaments in said winding space with one or more layers of said fiber cloth applied to form a preformed leaf spring comprises:

simultaneously winding the solution-impregnated fiber yarn and the solution-impregnated fiber cloth in the winding space in which one or more layers of the fiber cloth are laid to form the preformed plate spring.

12. The method of claim 1, wherein said curing said preformed leaf spring to provide a composite leaf spring body comprises:

curing and cutting the preformed plate spring to obtain a plurality of plate spring units to be processed;

winding one or more layers of fiber cloth impregnated by the solution on the fiber wire at the outermost layer of each leaf spring unit to be processed to obtain a preformed leaf spring unit;

and carrying out secondary curing on the preformed plate spring unit to obtain the composite material plate spring body.

13. The method according to claim 1, wherein the number of layers of the at least one layer of fiber filaments is in the range of 1 to 10, and the length of the fiber section is in the range of 20 to 100 mm.

14. A composite leaf spring body, comprising:

a composite leaf spring body made according to the method of any one of claims 1 to 13.

15. A leaf spring assembly, comprising:

the composite plate spring body prepared according to the method of any one of claims 1 to 13, wherein metal lugs are fixedly arranged at two ends of the composite plate spring body and fixedly connected with a vehicle frame, and the middle part of the composite plate spring body is fixed on a vehicle axle through a U-shaped bolt.

Technical Field

The present invention relates to a suspension for an automobile, and more particularly, to a method of manufacturing a composite leaf spring body based on winding molding for an automobile and a leaf spring body.

Background

With the increasing consumption of global fossil energy and the increasing emphasis on environmental issues, the speed of innovation of new materials and technology in the automobile industry is increasing. The lightweight car not only can greatly reduce the consumption of people to fossil energy, but also can improve the cargo capacity of the car and increase the service efficiency of the car. The composite material has the characteristics of light weight and high strength, and also has better shock absorption and fatigue life, so the composite material is widely applied to the field of automobiles.

The composite material is widely researched by a plurality of automobile manufacturers in recent years as a plate spring material for automobiles, and is also commercially applied to a part of automobile models.

In the related art, the forming process of the composite plate spring is generally divided into a continuous Filament Winding (fiber Winding) process and a compression Molding (Compressing Molding) process. The filament winding process may wind the filament impregnated with the resin around a mold having a fixed shape, and then cure the filament to obtain a molded product. However, the strength of the filament winding process is greatly affected by the bonding degree between filaments, and phenomena of weak interlayer bonding force, easy splitting and the like exist, so that the fatigue resistance and strength of the product are low, and the performance requirements of the plate spring cannot be well met. Therefore, most of manufacturers research and develop composite material plate springs by adopting a die pressing process, the precision of the composite material plate springs is high relative to a fiber winding process, and the surfaces of the composite material plate springs are smooth after products are formed without secondary processing. Resin Transfer Molding (RTM) is a typical Molding process, and specifically, a preformed fiber reinforcement material is placed in a mold cavity that requires peripheral sealing and fastening and ensures that the Resin flows smoothly inside; after the mould is closed, a certain amount of resin is injected, and after the resin is solidified, the desired product can be obtained by demoulding. The molding process can form a structural member having a complicated structure, but since the molding process is one-time molded, the time cost for production and the cost for loss of a mold are excessively high.

Therefore, how to produce the plate spring meeting the performance requirement on the basis of controlling the time cost and the die loss cost is a technical problem which needs to be solved urgently in the field.

Disclosure of Invention

The application provides a preparation method of a composite plate spring body based on winding forming and the plate spring body, which can produce a plate spring meeting performance requirements on the basis of controlling time cost and mould loss cost.

In a first aspect, the present application provides a method for manufacturing a composite leaf spring body based on winding molding, comprising:

passing the filaments through a solution formed on the basis of a thermosetting resin material or a thermoplastic resin material, so as to obtain filaments impregnated with the solution;

winding the solution-impregnated fiber filaments in a winding space in a mold matching the size of the plate spring to form a preformed plate spring; in the winding process, after winding at least one layer of fiber filaments, laying a layer of fiber felt on the surface of the at least one layer of fiber filaments, and embedding two ends of a fiber section in the layer of fiber felt into the at least one layer of fiber filaments in an arch form through a barbed needle head;

and curing the preformed plate spring to obtain the composite material plate spring body.

In the embodiment, the fiber felt layer is laid on the surface of the at least one layer of fiber, and the two ends of the fiber section in the fiber felt layer are embedded into the at least one layer of fiber in an arch form through the needle head with the barb, so that the fiber trend of the unidirectional fiber can be prevented from being disordered in the heating and curing process, the fiber in the vertical direction along the winding direction of the fiber can be enriched, the interlaminar strength, the interlaminar fracture toughness and the fatigue life can be further improved, and the composite plate spring body can meet the performance requirements; in addition, after the fiber filaments penetrate through the solution formed by the thermosetting resin material or the thermoplastic resin material, the fiber filaments are attached with the thermosetting resin material, so that the fiber filaments can be firmly bonded to the inside of the at least one layer of fiber filaments by the thermosetting resin material attached to the fiber filaments in the process of embedding the two ends of the fiber sections into the at least one layer of fiber filaments through the barbed needle head in an arched driving mode, and the strength of the composite plate spring body is further improved. In addition, because the present application is an improvement on the continuous filament winding process, the advantages of the continuous filament winding process, i.e., lower time cost and die loss cost, are retained.

In short, by laying a layer of fiber felt on the surface of at least one layer of fiber filaments and embedding both ends of a fiber segment in the layer of fiber felt into the at least one layer of fiber filaments in an arch form through a barbed needle, a leaf spring meeting performance requirements can be produced on the basis of controlling time cost and die loss cost.

In some possible implementations, the length of the fiber section is determined according to the number of layers of winding of the at least one layer of fiber filaments and the diameter of the fiber filaments for each layer of fiber mat in the preformed leaf spring.

In some possible implementations, the at least one layer of fiber filaments has a number of winding layers N, and the fiber filaments have a diameter M; wherein the length of the fiber segment is greater than or equal to 2M N + L + P, wherein L is proportional to the barb size, P is the offset, and M, N, L, P are all values greater than 0.

In this embodiment, the length of the fiber segment is designed to be greater than or equal to 2 × M × N + L + P, so that the depth of the fiber segment can be ensured to be greater than or equal to the thickness of the at least one layer of fiber filaments, that is, the two ends of the fiber segment in the one layer of fiber mat are embedded into the at least one layer of fiber filaments and the fiber mat below the at least one layer of fiber filaments in an arched manner through the barbed needle, that is, the intersection between the fiber segments in the two layers of fiber mats can be ensured, and further, the strength of the composite plate spring body can be further improved.

In some possible implementations, the length of the fiber segment is proportional to the total number of layers of windings of fiber filaments that have been wound on the mold for each layer of fiber mat in the preformed leaf spring.

In this embodiment, the length of the fiber segment is designed to be in direct proportion to the total number of winding layers of the fiber filaments wound on the mold, and it can be ensured that the depth of embedding the fiber segment is greater than or equal to the thickness of the at least one layer of fiber filaments, that is, the two ends of the fiber segment in the layer of fiber mat are embedded into the at least one layer of fiber filaments and the fiber mat below the at least one layer of fiber filaments in an arched manner through the needle head with the barb, that is, it can be ensured that the fiber segments in the two layers of fiber mats intersect with each other, and further, the strength of the composite plate spring body can be further improved.

In some possible implementations, at least one row of the needles is arranged in a direction perpendicular to the winding direction of the filament, the row having the same size as the winding space;

wherein, the barbed needle is used for embedding the two ends of the fiber segment in the layer of fiber felt into the at least one layer of fiber filaments in an arch shape, and the barbed needle comprises the following steps:

repeatedly inserting the needle head into the at least one layer of fiber yarns through the layer of fiber felt until the needle head is positioned at the end position of the at least one layer of fiber yarns in the winding space when the needle head is positioned above the initial area of the at least one layer of fiber yarns by rotating the mold; wherein, the needle head embeds the two ends of the fiber segment into the at least one layer of fiber filaments in an arch form through the barbs in the process of repeatedly inserting the at least one layer of fiber filaments.

In the embodiment of the application, the fiber yarns are wound in the winding space of the die in a rotating mode, so that the process complexity of winding the fiber yarns can be reduced, and the flowing operation and the batch production are facilitated. In addition, at least one row of the needle heads with the same size as the winding space is arranged in the vertical direction of the winding direction of the fiber yarns, so that the fiber yarns can be wound and simultaneously subjected to needling operation, the process complexity of the needling operation is further reduced, and the production line operation and the batch production are facilitated.

In some possible implementations, the repeatedly inserting the needle through the layer of fiber mat and into the at least one layer of fiber filaments includes:

the actual density of the needles inserted into the at least one layer of filaments is controlled by controlling the rotational speed of the die.

In this embodiment, through the mode of the slew velocity of controlling this mould, the actual density that this syringe needle inserted this at least one deck cellosilk can reduce the performance requirement to the syringe needle, avoids involving special syringe needle, can reduce research and development cost and equipment cost, and then, can the effective control combined material leaf spring body's manufacturing cost.

In some possible implementations, the density of the needles inserted into the at least one layer of filaments ranges from 2 to 200 needles per square centimeter.

In some possible implementations, the winding of the solution-impregnated fiber filaments in a winding space in the mold matching the size of the plate spring includes:

and winding the solution-impregnated fiber filaments in the winding space, and applying a tension less than a first threshold value and greater than a second threshold value to each of the fiber filaments impregnated with the solution during the winding, the first threshold value being determined according to a size of a space required when the needle is inserted into the at least one layer of fiber filaments.

In some possible implementations, the first threshold is inversely proportional to an amount of space required for the needle to be inserted into the at least one layer of filaments.

In the embodiment, the tension applied to each fiber filament impregnated with the solution in the winding process is designed to be smaller than a first threshold and larger than a second threshold, the first threshold is determined according to the size of the space required by the needle head when the needle head is inserted into the at least one layer of fiber filaments, and equivalently, in the process of applying the tension to each fiber filament, the requirement of the needle punching operation on the operation space can be met, the situation that the fiber filaments are broken due to the fact that the operation space is insufficient is avoided, equivalently, the continuity of the fiber filaments can be guaranteed in the needle punching operation process, and further, the performance of the composite plate spring body can be guaranteed.

In some possible implementations, the winding of the solution impregnated fiber filaments in a winding space in a mold matching the size of the leaf spring to form a preformed leaf spring includes:

passing a fiber cloth through the solution to obtain a fiber cloth impregnated with the solution;

laying one or more layers of fiber cloth impregnated with the solution in the winding space;

the solution-impregnated fiber filaments are wound in the winding space in which one or more layers of the fiber cloth are laid to form the preformed plate spring.

In this embodiment, through in this winding space that has laid this fibre cloth of one deck or multilayer, twine the cellosilk through this solution flooding to form this preforming leaf spring, be equivalent to, under the condition of combined material leaf spring body atress, this fibre cloth can alleviate the interlaminar shearing that the cellosilk bore, and then is favorable to avoiding taking place the dislocation between the fashioned cellosilk of winding, and then, can guarantee the performance of combined material leaf spring body. Optionally, the fiber cloth comprises two vertical fibers, and the two vertical fibers and the wound fiber form an included angle of 45 degrees, so as to further improve the stress performance of the fiber cloth.

In some possible implementations, the winding of the solution-impregnated fiber filaments in the winding space where one or more layers of the fiber cloth are laid to form a preformed plate spring includes:

simultaneously winding the solution-impregnated fiber yarn and the solution-impregnated fiber cloth in the winding space in which one or more layers of the fiber cloth are laid to form the preformed plate spring.

In some possible implementations, the pair of preformed leaf springs is cured, resulting in a composite leaf spring body comprising:

curing and cutting the preformed plate spring to obtain a plurality of plate spring units to be processed;

winding one or more layers of fiber cloth impregnated by the solution on the fiber yarn at the outermost layer of each leaf spring unit to be processed to obtain a preformed leaf spring unit;

and carrying out secondary curing on the preformed plate spring unit to obtain the composite material plate spring body.

In this embodiment, a preformed leaf spring unit is cured twice to obtain a composite leaf spring body. To the preforming leaf spring unit winding after tailorring through the one deck or the multilayer fibre cloth of this solution flooding, can tailor the technology and produce the destruction to the structure of fibre cloth, and then, can guarantee the promotion effect of fibre cloth to the mechanical properties of leaf spring body.

In some possible implementations, the number of layers of the at least one layer of fiber filaments ranges from 1 to 10, and the length of the fiber section ranges from 20 to 100 mm.

In a second aspect, there is provided a composite leaf spring body comprising:

a composite leaf spring body made according to the first aspect or the method described in any one of the possible implementations of the first aspect.

In a third aspect, a leaf spring assembly is provided, comprising:

the composite plate spring body is prepared according to the first aspect or any one of the possible implementation manners of the first aspect, the two ends of the composite plate spring body are fixedly provided with metal lugs, the metal lugs are fixedly connected with a vehicle frame, and the middle part of the composite plate spring body is fixed on an axle through a U-shaped bolt.

Drawings

Fig. 1 is a schematic view of the installation of the leaf spring assembly provided in the present application.

Fig. 2 is a schematic view of a composite leaf spring assembly provided in an embodiment of the present application.

Fig. 3 is a schematic flow chart of a manufacturing method of a composite plate spring body based on winding forming provided by an embodiment of the application.

Detailed Description

The technical solutions in the embodiments of the present application will be described below with reference to the accompanying drawings.

The leaf spring can be placed in the longitudinal direction or in the transverse direction on the motor vehicle. The latter has to be provided with additional guiding force-transmitting devices for transmitting longitudinal force, which makes the structure complicated and the mass enlarged, so the latter is only applied to a few light and miniature vehicles. The longitudinal leaf spring can transmit various forces and moments, has a guiding function, and is simple in structure, so that the longitudinal leaf spring is widely applied to automobiles.

Fig. 1 is a schematic view of the installation of the leaf spring assembly provided in the present application.

As shown in fig. 1, the leaf spring assembly includes a leaf spring body 13, two U-bolts 14 are provided in the middle of the leaf spring body 13 for fixing the leaf spring body 13 to the axle 15, and the front end of the leaf spring body 13 is fixed to the vehicle body 11 (frame) through the front rolling lug 131 of the leaf spring body 13 and the front bracket 12; the rear end of the steel plate leaf spring body 13 is fixed to the vehicle body 11 (vehicle frame) via the rear lug 132 of the steel plate leaf spring body 13, the lug 16, and the rear bracket 17.

The steel plate leaf spring body 13 can be composed of a plurality of steel plates, the width of the single steel plate body is unchanged, the thickness of the single steel plate body is equal to the thickness of the single steel plate body, the single steel plate body has two types of sections, namely an equal section and a variable section, the variable section is also divided into a linear variable section and a parabolic variable section, and the parabolic variable section is mostly adopted for the variable section leaf spring because the stress of each part of the parabolic variable section is equal.

With technological development, composite materials are increasingly used for automotive suspension spring elements. The composite material has high specific strength modulus, and good fatigue resistance, damping performance and corrosion resistance, so that the composite material is used as an elastic element, the smoothness and comfort of a vehicle can be greatly improved, the mass is only about 1/4 of a steel plate spring, the fuel efficiency is effectively improved, the unsprung mass is reduced, the unsprung vibration is reduced, the service life is greatly prolonged, the elastic element does not need to be replaced within the service life range of the whole vehicle, and the use and maintenance cost of the whole vehicle is relatively low.

The concept of composite material means that one material can not meet the use requirement, and two or more materials are required to be compounded together to form another material which can meet the requirement of people, namely the composite material. As an example, a single glass fiber, although strong, is loose, can only withstand tensile forces, cannot withstand bending, shearing, and compressive stresses, and cannot be easily formed into a fixed geometric shape, which is a loose body. If they are bonded together with synthetic resin, they can be made into various rigid products with fixed shapes, which can bear not only tensile stress, but also bending, compression and shearing stress, and can be formed into glass fiber reinforced plastic matrix composite material. Because the strength of the glass fiber reinforced plastic is equivalent to that of steel, the glass fiber reinforced plastic also contains glass components and has the properties of color, shape, corrosion resistance, electric insulation, heat insulation and the like similar to glass, and the glass fiber reinforced plastic can be also called as glass fiber reinforced plastic.

Composite materials are of many types and generally consist of a reinforcement material and a matrix material, for example, reinforced concrete is also a composite material, concrete is a matrix, and reinforced steel is a reinforcement material.

The matrix material includes, but is not limited to, epoxy resin, polyester resin, thermoplastic resin, and the like. For example, the matrix material may be a resin matrix, i.e. a matrix of a resin-based composite material. The resin matrix refers to a glue solution system consisting of resin and a curing agent. As an example, the resin matrix may include a thermosetting resin and a thermoplastic resin. Thermosetting resins can be heated and molded only once and cured during processing to form infusible and insoluble network cross-linked high molecular compounds, and thus cannot be regenerated. The resin matrix of the composite material is mainly thermosetting resin. Thermosetting resins include, but are not limited to: phenolic resins, urea-formaldehyde resins, melamine-formaldehyde resins, epoxy resins, unsaturated resins, polyurethanes, polyimides, and the like. Reinforcing materials include, but are not limited to, carbon fibers, glass fibers, aramid fibers, and the like.

Reinforcing materials include, but are not limited to, carbon fibers, glass fibers, aramid fibers, and the like. The reinforcing material may be reinforcing fibres (Reinforced fibers), i.e. reinforcement of a resin-based composite material. By way of example, the reinforcing material includes, in terms of geometry, zero-dimensional particles, one-dimensional fibers, two-dimensional sheets (e.g., cloths or felts), and three-dimensional solid structures. Inorganic reinforcing materials and organic reinforcing materials, which may be synthetic or natural, are classified by their properties. The inorganic reinforcing material may be fibrous, such as inorganic glass fibers, carbon fibers, and a small amount of ceramic fibers such as silicon carbide, and the organic reinforcing material may include aramid fibers (aramid fibers) and the like.

As an example, the reinforcing material of the composite plate spring body according to the present application may be glass fiber, carbon fiber, or a fiber bundle composed of glass fiber and carbon fiber, and the matrix material thereof may be epoxy resin or the like, which may also be referred to as a fiber-Reinforced Plastic (FRP) plate spring body.

Compared with the traditional metal material, the characteristics of the composite plate spring are mainly characterized by high specific strength, high specific modulus, good temperature resistance, good impact resistance, strong designability, more than 70% weight reduction, safe fracture and the like. Many foreign countries have used composite leaf springs in mass production vehicles, and many automobile manufacturers both at home and abroad are developing composite leaf springs. The installation of a composite leaf spring is similar to the installation of a steel leaf spring, requiring the middle to be fixed to the axle like a steel leaf spring, with both ends connected to the body. However, since it is difficult to make the eye at both ends of the composite plate spring, it is necessary to make the member like the eye.

Fig. 2 is a schematic view of a composite leaf spring assembly provided in an embodiment of the present application.

As shown in fig. 2, the composite leaf spring assembly 20 may include a composite leaf spring body 23, both ends of the composite leaf spring body 23 being provided with a lug-like member 231 and 232, respectively, to connect both ends of the composite leaf spring body 23 to a vehicle body (frame); the middle part of the composite leaf spring body 23 is fixed to the axle by a U-bolt 24. As one example provided herein, the lug-like members 231 and 232 may be frame hinge barrels. Optionally, the ear-like members 231 and 232 may further include a plate spring clamping plate, and the frame hinge tube is fixedly connected to the plate spring clamping plate, for example, the plate spring clamping plate and the frame hinge tube may form a U-shaped structure; alternatively, the plate spring clamping plate may be disposed inside the composite plate spring body 23, or may be fixedly connected to the composite plate spring body 23 through a fastening bolt.

The forming process of the composite plate spring is generally classified into a continuous Filament Winding (Filament Winding) process and a compression Molding (compression Molding) process. The filament winding process may wind the filament impregnated with the resin around a mold having a fixed shape, and then cure the filament to obtain a molded product. However, the strength of the filament winding process is greatly affected by the bonding degree between filaments, and phenomena of weak interlayer bonding force, easy splitting and the like exist, so that the fatigue resistance and strength of the product are low, and the performance requirements of the plate spring cannot be well met. Therefore, most of manufacturers research and develop composite material plate springs by adopting a die pressing process, the precision of the composite material plate springs is high relative to a fiber winding process, and the surfaces of the composite material plate springs are smooth after products are formed without secondary processing. Resin Transfer Molding (RTM) is a typical Molding process, and specifically, a preformed fiber reinforcement material is placed in a mold cavity that requires peripheral sealing and fastening and ensures that the Resin flows smoothly inside; after the mould is closed, a certain amount of resin is injected, and after the resin is solidified, the desired product can be obtained by demoulding. The molding process can form a structural member having a complicated structure, but since the molding process is one-time molded, the time cost for production and the cost for loss of a mold are excessively high.

Based on the method, the composite plate spring body is prepared by winding and forming, and the plate spring body can be produced on the basis of controlling time cost and mould loss cost. For example, the plate spring can meet the requirements of the composite plate spring body on the retention rate of bending strength, interlaminar shear strength and the like, particularly the requirement on the retention rate of mechanical properties in a high-temperature scene on the basis of controlling time cost and die loss cost. Wherein the interlaminar shear strength is used to evaluate interlaminar performance.

Fig. 3 is a schematic flow chart of a manufacturing method 30 based on winding-formed composite leaf spring body provided in the embodiment of the present application.

As shown in fig. 3, the preparation method 30 may include:

s31, passing the fiber filament through a solution formed based on a thermosetting resin material or a thermoplastic resin material to obtain a fiber filament impregnated with the solution;

s32, winding the solution-impregnated fiber yarn in a winding space matched with the size of the plate spring in a mold to form a preformed plate spring; in the winding process, after winding at least one layer of fiber filaments, laying a layer of fiber felt on the surface of the at least one layer of fiber filaments, and embedding two ends of a fiber section in the layer of fiber felt into the at least one layer of fiber filaments in an arch form through a barbed needle head;

and S33, solidifying the preformed plate spring to obtain the composite plate spring body.

For example, if the solution is a thermosetting resin solution, the preformed leaf spring may be heat cured to obtain a composite leaf spring body.

In the embodiment, the fiber felt layer is laid on the surface of the at least one layer of fiber, and the two ends of the fiber section in the fiber felt layer are embedded into the at least one layer of fiber in an arch form through the needle head with the barb, so that the fiber trend of the unidirectional fiber can be prevented from being disordered in the heating and curing process, the fiber in the vertical direction along the winding direction of the fiber can be enriched, the interlaminar strength, the interlaminar fracture toughness and the fatigue life can be further improved, and the composite plate spring body can meet the performance requirements; in addition, after the fiber filaments penetrate through the solution formed by the thermosetting resin material or the thermoplastic resin material, the fiber filaments are attached with the thermosetting resin material, so that the fiber filaments can be firmly bonded to the inside of the at least one layer of fiber filaments by the thermosetting resin material attached to the fiber filaments in the process of embedding the two ends of the fiber sections into the at least one layer of fiber filaments through the barbed needle head in an arched driving mode, and the strength of the composite plate spring body is further improved. In addition, because the present application is an improvement on the continuous filament winding process, the advantages of the continuous filament winding process, i.e., lower time cost and die loss cost, are retained.

In short, by laying a layer of fiber felt on the surface of at least one layer of fiber filaments and embedding both ends of a fiber segment in the layer of fiber felt into the at least one layer of fiber filaments in an arch form through a barbed needle, a leaf spring meeting performance requirements can be produced on the basis of controlling time cost and die loss cost.

In other words, the process of embedding the two ends of the fiber segment into the at least one layer of fiber filaments by the arched driving of the barbed needle can be called as the "needling" operation.

In the field of manufacturing process, the matrix material, the reinforcing material, the winding method and other process parameters must be matched with each other, otherwise, the reinforcing effect of the fiber cannot be fully exerted, and further the strength is greatly influenced. In general, for different products (for example, composite materials formed by different matrix materials and reinforcing materials), a set of preparation processes specially designed for the products are required to achieve the expected effect. According to the scheme provided by the application, aiming at the continuous fiber winding process, a 'needling' operation flow is specially designed in the winding operation flow so as to improve the retention rates of bending strength, interlaminar shear strength and the like.

In addition, the specific types of the fiber filaments and the thermosetting resin material are not limited in the embodiments of the present application.

For example, the fiber yarn may be a synthetic fiber yarn, which is a connecting material obtained by melting a polymer at a high temperature and a high pressure, ejecting a fluid yarn from a nozzle having an extremely fine pore diameter, solidifying the fluid yarn, processing the solidified fluid yarn into a fiber, and spinning the fiber into a yarn. The connecting thread made of synthetic fiber has high strength, can be sewn with thin thread without breaking, and has good firmness and no joint. For another example, the thermosetting resin material may also be referred to as a thermosetting adhesive or a thermosetting resin adhesive. The thermosetting resin adhesive may be an adhesive using a thermosetting resin containing a reactive group as a binder. When the curing agent is added or heated, the liquid binder molecules can be further polymerized and crosslinked into a three-dimensional net structure to form an infusible solid adhesive layer so as to achieve the purpose of adhesive bonding. The thermosetting resin material can be heat-cured, which may also be referred to as a heat-curable adhesive. The thermosetting resin material can be liquid at normal temperature, can exist stably at room temperature, and does not change the chemical components and properties of the resin during storage.

In addition, the embodiment of the present application does not limit the specific implementation manner of winding the fiber filaments in the winding space of the mold.

For example, the winding manner in the embodiment of the present application depends on the shape or configuration of the winding space. For example, the winding can be performed from left to right or from right to left for a horizontally placed mold, and from bottom to top or from bottom to top for a vertically placed mold. As an example, the fiber filaments impregnated with the solution may be uniformly wound in the winding space to form a preformed plate spring. For example, a first layer of fiber filaments may be wound in the winding space in the order from left to right, then a second layer of fiber filaments may be wound on the surface of the first layer of fiber filaments in the order from right to left, then a third layer of fiber filaments may be wound on the surface of the second layer of fiber filaments in the order from left to right, and so on until the winding space is filled with the wound fiber filaments.

In some embodiments, the length of the fiber section is determined according to the number of layers of winding of the at least one layer of fiber filaments and the diameter of the fiber filaments for each layer of fiber mat in the preformed leaf spring. As an example, the at least one layer of fiber filaments has a number of winding layers N, and the fiber filaments have a diameter M; wherein the length of the fiber segment is greater than or equal to 2M N + L + P, wherein L is proportional to the barb size, P is the offset, and M, N, L, P are all values greater than 0.

In this embodiment, the length of the fiber segment is designed to be greater than or equal to 2 × M × N + L + P, so that the depth of the fiber segment can be ensured to be greater than or equal to the thickness of the at least one layer of fiber filaments, that is, the two ends of the fiber segment in the one layer of fiber mat are embedded into the at least one layer of fiber filaments and the fiber mat below the at least one layer of fiber filaments in an arched manner through the barbed needle, that is, the intersection between the fiber segments in the two layers of fiber mats can be ensured, and further, the strength of the composite plate spring body can be further improved.

In some embodiments, the length of the fiber segment is proportional to the total number of layers of fiber filament windings that have been wound on the die for each layer of fiber mat in the preformed leaf spring.

In this embodiment, the length of the fiber segment is designed to be in direct proportion to the total number of winding layers of the fiber filaments wound on the mold, and it can be ensured that the depth of embedding the fiber segment is greater than or equal to the thickness of the at least one layer of fiber filaments, that is, the two ends of the fiber segment in the layer of fiber mat are embedded into the at least one layer of fiber filaments and the fiber mat below the at least one layer of fiber filaments in an arched manner through the needle head with the barb, that is, it can be ensured that the fiber segments in the two layers of fiber mats intersect with each other, and further, the strength of the composite plate spring body can be further improved.

In some embodiments, at least one row of the needles is arranged in a direction perpendicular to the winding direction of the filament, the row having the same size as the winding space; wherein, the S32 may include:

repeatedly inserting the needle head into the at least one layer of fiber yarns through the layer of fiber felt until the needle head is positioned at the end position of the at least one layer of fiber yarns in the winding space when the needle head is positioned above the initial area of the at least one layer of fiber yarns by rotating the mold; wherein, the needle head embeds the two ends of the fiber segment into the at least one layer of fiber filaments in an arch form through the barbs in the process of repeatedly inserting the at least one layer of fiber filaments.

In the embodiment of the application, the fiber yarns are wound in the winding space of the die in a rotating mode, so that the process complexity of winding the fiber yarns can be reduced, and the flowing operation and the batch production are facilitated. In addition, at least one row of the needle heads with the same size as the winding space is arranged in the vertical direction of the winding direction of the fiber yarns, so that the fiber yarns can be wound and simultaneously subjected to needling operation, the process complexity of the needling operation is further reduced, and the production line operation and the batch production are facilitated.

In one implementation, the actual density of the needles inserted into the at least one layer of filaments is controlled by controlling the speed of rotation of the die.

As an example, the rotational speed of the die, and thus the actual density of the needles inserted into the at least one layer of filaments, may be controlled based on the frequency of insertion of the needles into the at least one layer of filaments. Of course, in other alternative embodiments, the frequency of the needles inserted into the at least one layer of filaments may be controlled or set based on the rotational speed of the die, thereby controlling the actual density of the needles inserted into the at least one layer of filaments. In a specific implementation, the rotational speed of the mold can be controlled by a servomotor, which can be a micro-motor, also called an actuator motor, used as an actuator in an automatic control device, whose function can be to convert an electrical signal into an angular displacement and/or angular velocity of the rotating shaft.

In this embodiment, through the mode of the slew velocity of controlling this mould, the actual density that this syringe needle inserted this at least one deck cellosilk can reduce the performance requirement to the syringe needle, avoids involving special syringe needle, can reduce research and development cost and equipment cost, and then, can the effective control combined material leaf spring body's manufacturing cost.

In one implementation, the density of the needle inserted into the at least one layer of filaments is in the range of 2 to 200 needles per square centimeter.

Of course, the above numerical values are merely examples of the present application and should not be construed as limiting the present application. For example, in other alternative embodiments, the density of the needles inserted into the at least one layer of filaments ranges from 50 to 100 needles per square centimeter. For another example, the density range of the needle inserted into the edge area of the at least one layer of fiber filaments is larger than the density range of the needle inserted into the central area of the at least one layer of fiber filaments; in one implementation, the density of the needles in at least one row in the edge region of the at least one layer of filaments is greater than the density of the needles in the central region of the at least one layer of filaments.

In some embodiments, the S32 may include:

and winding the solution-impregnated fiber filaments in the winding space, and applying a tension less than a first threshold value and greater than a second threshold value to each of the fiber filaments impregnated with the solution during the winding, the first threshold value being determined according to a size of a space required when the needle is inserted into the at least one layer of fiber filaments. In one implementation, the first threshold is inversely proportional to the amount of space required for the needle to be inserted into the at least one layer of filaments.

As an example, the fiber yarn, which is mounted on a yarn roll, is passed through a dip tank to obtain a fiber yarn impregnated with the solution. In this case, a set of friction rollers may be provided between the yarn roller and the dip tank so that the fiber yarn is stretched to have a certain tension before entering the dip tank. Of course, the application of tension to each filament may be controlled by other tensioning devices. Alternatively, the first threshold may be equal to 50 newtons and the second threshold may be 30 newtons, although these values are merely examples of the present application and should not be construed as limiting the present application. Optionally, in order to implement intelligent operation, the tension applied to each fiber yarn may be controlled through a display screen and a human-computer interface. Optionally, since the composite plate spring body should be preferably manufactured in an environment with a certain temperature to sufficiently soak the fiber filaments into the resin material, a constant temperature heating device and/or a constant temperature heating bath may be further provided in the dipping tank. The constant temperature heating device or the constant temperature heating bath can be realized by a heating pipe, the temperature is mostly 60 +/-20 ℃, and the method belongs to the technology which can be mastered by the technical personnel in the field and is not described in detail.

In the embodiment, the tension applied to each fiber filament impregnated with the solution in the winding process is designed to be smaller than a first threshold and larger than a second threshold, the first threshold is determined according to the size of the space required by the needle head when the needle head is inserted into the at least one layer of fiber filaments, and equivalently, in the process of applying the tension to each fiber filament, the requirement of the needle punching operation on the operation space can be met, the situation that the fiber filaments are broken due to the fact that the operation space is insufficient is avoided, equivalently, the continuity of the fiber filaments can be guaranteed in the needle punching operation process, and further, the performance of the composite plate spring body can be guaranteed.

In some possible implementations, the S32 may include:

passing a fiber cloth through the solution to obtain a fiber cloth impregnated with the solution; laying one or more layers of fiber cloth impregnated with the solution in the winding space; the solution-impregnated fiber filaments are wound in the winding space in which one or more layers of the fiber cloth are laid to form the preformed plate spring. Optionally, the fiber cloth is laid on the bottom and side surfaces of the winding space.

In other words, the bottom and side surfaces of the winding fiber can be covered with a layer of fiber cloth.

In this embodiment, through in this winding space that has laid this fibre cloth of one deck or multilayer, twine the cellosilk through this solution flooding to form this preforming leaf spring, be equivalent to, under the condition of combined material leaf spring body atress, this fibre cloth can alleviate the interlaminar shearing that the cellosilk bore, and then is favorable to avoiding taking place the dislocation between the fashioned cellosilk of winding, and then, can guarantee the performance of combined material leaf spring body. Optionally, the fiber cloth comprises two vertical fibers, and the two vertical fibers and the wound fiber form an included angle of 45 degrees, so as to further improve the stress performance of the fiber cloth.

In one implementation, the solution-impregnated fiber filaments and the solution-impregnated fiber cloth are simultaneously wound in the winding space in which one or more layers of the fiber cloth are laid to form the preformed leaf spring.

As an example, after winding at least one layer of fiber filament and at least one layer of fiber cloth, laying a layer of fiber felt on the surface of the at least one layer of fiber filament, and embedding the two ends of the fiber segment in the layer of fiber felt into the at least one layer of fiber filament and the at least one layer of fiber cloth in an arch shape through a barbed needle head. In other words, the at least one layer of fiber filaments and the at least one layer of fiber cloth are arranged in a staggered manner, the first layer of the at least one layer of fiber filaments and the at least one layer of fiber cloth is a layer of fiber cloth, and the last layer is a layer of fiber filaments.

In one implementation, the S33 may include:

curing and cutting the preformed plate spring to obtain a plurality of plate spring units to be processed; winding one or more layers of fiber cloth impregnated by the solution on the fiber yarn at the outermost layer of each leaf spring unit to be processed to obtain a preformed leaf spring unit; and carrying out secondary curing on the preformed plate spring unit to obtain the composite material plate spring body.

In this embodiment, a preformed leaf spring unit is cured twice to obtain a composite leaf spring body. To the preforming leaf spring unit winding after tailorring through the one deck or the multilayer fibre cloth of this solution flooding, can tailor the technology and produce the destruction to the structure of fibre cloth, and then, can guarantee the promotion effect of fibre cloth to the mechanical properties of leaf spring body. Optionally, the fiber cloth comprises two vertical fibers, and the two vertical fibers and the wound fiber form an included angle of 45 degrees, so as to further improve the stress performance of the fiber cloth.

Of course, in other alternative embodiments of the present application, the upper side of the twisted filament may be covered with a layer of fiber cloth. For example, one or more layers of fiber cloth impregnated with the solution may be wound on the outermost layer of fiber yarn at the end of winding the fiber yarn to obtain the preformed plate spring, and then the preformed plate spring is cured and cut, and one unit after cutting may be used as a composite plate spring body.

It should be noted that the specific type of the fiber cloth is not limited in the examples of the present application. For example, the fiber cloth according to the embodiment of the present application may be a carbon fiber cloth, a carbon fiber fabric, a carbon fiber tape, a carbon fiber sheet, a prepreg, or the like. The composite material made of the carbon fiber has the characteristics of extremely high strength, ultralight weight, high temperature and high pressure resistance and the like.

In some embodiments, the number of layers of the at least one layer of fiber filaments ranges from 1 to 10, and the length of the fiber segment ranges from 20 to 100 mm.

Of course, in other alternative embodiments, the range of the number of layers of the at least one layer of fiber filaments and/or the range of the length of the fiber segment may also be other values, which is not specifically limited in the embodiments of the present application. For example, the at least one layer of fiber filaments has a number of layers of 20.

The application also provides a composite plate spring body prepared by the preparation method of the composite plate spring body based on winding forming. It is to be understood that the composite leaf spring body embodiments and the method embodiments of making the composite leaf spring body can correspond to each other and similar descriptions can be made with reference to specific embodiments of the composite material. For brevity, no further description is provided herein.

It should be understood that the leaf spring body, the composite leaf spring, and the composite leaf spring body described in this specification can all be resin-based fiber composite leaf spring bodies.

It will also be appreciated that the embodiments of the method of making a composite leaf spring body enumerated above may be performed by robotic or numerically controlled machining, and that the apparatus software or process for performing the method may perform the method by executing computer program code stored in memory. It should be noted that, without conflict, the embodiments and/or technical features in the embodiments described in the present application may be arbitrarily combined with each other, and the technical solutions obtained after the combination also fall within the protection scope of the present application. It should be understood that, in the various embodiments of the present application, the sequence numbers of the above-mentioned processes do not mean the execution sequence, and the execution sequence of each process should be determined by its function and inherent logic, and should not constitute any limitation to the implementation process of the embodiments of the present application.

Those of ordinary skill in the art will appreciate that the various illustrative methods of making described in connection with the embodiments disclosed herein may be implemented as electronic hardware, or combinations of computer software and electronic hardware. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the implementation. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present application.

The above description is only for the specific embodiments of the present application, but the scope of the present application is not limited thereto, and any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present application, and shall be covered by the scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.