A process for making a composite axle housing assembly for an automotive chassis

Abstract

The application relates to the automobile field, in particular to a manufacturing process of a composite axle shell assembly for an automobile chassis, wherein the axle shell assembly comprises a reducer shell, a rear cover shell and a half axle shell; the reducer shell and the rear cover shell are formed through a prepreg mold forming process; and the half axle shell is formed through a winding forming process. The manufacturing process is fast and efficient, and the prepared axle shell has the characteristics of light weight, high strength and rust resistance.

Description

Technical Field

[0001] This invention relates to the automotive field, and specifically to a manufacturing process for a composite material axle housing assembly used in automotive chassis. Background Technology

[0002] As a crucial structural component of a vehicle chassis, the axle is connected to the frame via the suspension. Tires are mounted on either side of the axle, and its function is to support the vehicle's weight and withstand the road reaction forces and torques transmitted from the wheels to the frame via the suspension. The axle housing, as the main part of the axle, is a key component ensuring the normal operation and lifespan of the vehicle, requiring high strength, rigidity, and fatigue resistance. If the housing breaks during vehicle operation, the vehicle's load-bearing capacity will decrease, potentially leading to accidents. Therefore, the axle housing has a critical impact on driving safety and overall vehicle comfort. Currently, most automotive axle housings are made of cast steel, which is of high quality and affects fuel efficiency and driving range.

[0003] Therefore, the inventors conducted further research and developed a manufacturing process for a composite material axle housing assembly for automobile chassis, which led to this invention. Summary of the Invention

[0004] The purpose of this invention is to provide a manufacturing process for a composite material axle housing assembly for automobile chassis. This manufacturing method is fast, efficient, and produces an axle housing that is lightweight, high-strength, and rust-resistant.

[0005] To achieve the above objectives, the technical solution of the present invention is as follows:

[0006] A manufacturing process for a composite material axle housing assembly for an automobile chassis, comprising a reducer housing, a rear cover housing, and a half-shaft housing. The reducer housing and rear cover housing are manufactured using a prepreg molding process, while the half-shaft housing is manufactured using a winding process. The specific manufacturing steps are as follows:

[0007] The molding process for the reducer housing and rear cover housing includes:

[0008] Step A1: Analyze the load on the housing and design the plywood: Calculate the distribution of the maximum bending load force that the housing will bear when it is bent based on the load conditions of the reducer housing and the rear cover housing during operation, and select materials and plywood design to ensure that the required strength and stiffness are achieved.

[0009] Step A2, Mold Design: Prepare a mold with an inner cavity shape corresponding to the reducer housing and the rear cover housing. The part of the mold cavity corresponding to the reducer housing is the reducer housing cavity, and the part corresponding to the rear cover housing is the rear cover housing cavity. Use a clean white cotton cloth dipped in release agent to wipe the mold cavity thoroughly. At the same time, preheat the mold to 40℃-60℃.

[0010] Step A3, Prepreg preparation: Cut the carbon fiber and basalt fiber fabrics according to the shape of the reducer housing and the rear cover housing, then mix the above fiber fabrics with resin to obtain prepreg and preheat at 40°C;

[0011] Step A4, Shell Molding: The preheated prepreg is laid in the mold according to the design. The prepreg is impregnated, flows and fills the mold cavity under pressure. Finally, after pressure holding and cooling, it is demolded to complete the molding process.

[0012] Step A5, Post-molding processing: After demolding, the product is trimmed and punched to obtain the final product;

[0013] The fabrication steps for the half-shaft housing are as follows:

[0014] Step B1: Analyze the load on the shell and design the layup: Calculate the distribution of the maximum torsional force that the half shaft will bear during torsion based on the load conditions of the half shaft shell, select the fiber material and design the layup.

[0015] Step B2, Mandrel Manufacturing and Winding Machine Setup: Prepare steel mandrels of the required dimensions and adjust the winding machine system;

[0016] Step B3, Preparation of prepreg tape: Place the reinforcing fibers in the resin tank of the winding machine, and then inject resin to mix thoroughly with the fibers;

[0017] Step B4, winding of prepreg tape: Under the control of the drive control system, the mandrel rotates at a predetermined speed, and the resin tank moves back and forth at a set speed, so that the prepreg tape is arranged in a spiral on the mandrel.

[0018] Step B5, Curing of Prepreg Tape: Place the prepreg tape wound on the mandrel into a constant temperature oven and set the temperature and time for curing;

[0019] Step B6: Post-curing treatment.

[0020] Furthermore, in step A2, the mold adopts a rounded corner design; in step A3, epoxy resin is selected as the resin.

[0021] Furthermore, in step A2, the design of the connection between the reducer housing and the half shaft is added, using a spline connection plus adhesive connection. The internal spline has a total of 8 keyways and three reinforcing ribs. The adhesive selected is 3M DP460 structural adhesive.

[0022] Furthermore, in step A4, the prepreg is preheated and immediately laid into the preheated mold.

[0023] Furthermore, in step A2, the reducer housing is connected to the composite material housing by means of adhesive and hinge connection. The composite material reinforcing ribs are connected to the metal splines by adhesive, and 3M DP460 structural adhesive is selected as the adhesive.

[0024] Furthermore, in step A4, the inner surface of the reducer housing is padded with 30 layers at a 0° ply angle, the reinforcing ribs with 50 layers at a 45° ply angle, the cylindrical interface with 40 layers at a ±45° ply angle, the remaining outer surface of the reducer housing with 40 layers at a 0° / 45° / -45° / 0° ply angle, and the rear cover housing with 30 layers in a 0° / 45° / -45° ply sequence. To reduce stress concentration at the opening of the rear cover housing, 10 layers of prepreg with a ±45° ply angle are added at the opening to ensure the reliability of the opening.

[0025] Furthermore, in step B1, 30 layers are laid using a 45° / -45° ply pattern.

[0026] Furthermore, in step B2, the end connection of the core mold adopts an external spline connection combined with adhesive bonding. The external spline has 8 keyways, and 3M DP460 structural adhesive is selected as the adhesive.

[0027] Furthermore, in step B3, the temperature is controlled during the preparation of the prepreg to remove residual solvent, while preventing the prepreg tape from curing and generating bubbles.

[0028] Furthermore, in step A4, after curing, the internal spline of the metal is connected to the inner and outer surfaces of the shell by means of adhesive and hinge. The cylindrical interface is connected to the shell by means of adhesive, and the reinforcing rib is connected to the spline and the outer surface of the shell by means of adhesive.

[0029] Furthermore, in step B5, the metal external spline is connected to the prepreg tape wrapped around the mandrel using an adhesive, and then placed in a constant temperature oven for curing.

[0030] By adopting the above solution, the present invention has the following advantages compared with the prior art:

[0031] The composite axle housing assembly is made of fiber-reinforced resin matrix composite material. Under the premise of the same stiffness, the weight of the composite axle housing assembly can be more than 40% lighter than that of the metal axle housing assembly. In addition, due to the superior properties of composite materials, such as high specific strength and specific modulus, rust resistance, good fatigue resistance, and good damping and shock absorption performance, the load-bearing capacity and energy storage capacity of the composite axle housing are also better than those of the metal axle housing. The overall performance of the composite axle housing is significantly better than that of the metal axle housing, and it has good application prospects. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the axle housing assembly structure of the present invention;

[0033] Figure 2 This is a schematic diagram of the reducer housing structure;

[0034] Figure 3 This is a schematic diagram of the half-shaft housing structure;

[0035] Figure 4 This is a schematic diagram of the rear cover shell structure;

[0036] Figure 5 This is a flowchart of the compression molding process;

[0037] Figure 6 This is a flow chart of the winding molding process;

[0038] Figure 7 This is a schematic diagram of the cross-section of the half-shaft housing;

[0039] Label Explanation

[0040] Half-shaft housing 1, reducer housing 2, rear cover housing 3, reinforcing rib 4, internal spline 5, external spline 6, plain weave fabric 7. Detailed Implementation

[0041] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0042] like Figure 1 As shown, a composite material axle housing consists of a reducer housing, a half-shaft housing, and a rear cover housing. The composite material is composed of thermoplastic resin as the matrix and basalt, carbon fiber, or glass fiber as reinforcing fibers.

[0043] In order to ensure that the performance of the composite material is not affected during the molding process, the mold and prepreg are preheated in advance, and the laying should be done as quickly as possible to reduce the contact time with air.

[0044] like Figure 2 , 4As shown, in order to avoid damaging the fibers during laying, which would affect the quality of the prepreg and ultimately the performance of the final molded product, a rounded corner design was adopted for the straight edges.

[0045] like Figure 2 , 3 As shown, to ensure the reliability of the housing connection, a spline connection is used at the connection between the half-shaft and the reducer. There are 8 keyways on both the inner and outer splines, which increases the contact area and improves the load-bearing capacity. At the same time, 3 reinforcing ribs are added to increase the rigidity and strength of the housing. In addition, to enhance the connection effect, 3M DP460 structural adhesive is used for bonding. This adhesive expands when curing, which can improve the connection effect. The adhesive has a large fracture strain and can withstand a high fatigue limit stress, which increases fatigue life and improves the reliability of the connection.

[0046] In the molding process, in order to ensure the quality of the mold and the final product, a clean white cotton cloth is used to apply release agent to the entire cavity of the molding mold. This is done 3 to 5 times, with an interval of 15 to 20 minutes between each application, and the last application is left for more than 30 minutes.

[0047] like Figure 7 In order to give the half-shaft housing 1 the best torsional resistance, the reinforcing fiber winding in the composite material adopts a -45° / 45° winding method, that is, the warp and weft reinforcing fibers are cross-wound to form plain weave fabric 7. This plain weave fabric can not only ensure the strength of the half-shaft housing 1, but also enhance the fatigue life and impact resistance of the housing 1.

[0048] According to the mechanics of materials, under torsional deformation conditions, when the direction of the reinforcing fiber arrangement forms an acute angle with the axial direction, the acute angle ranges from 30° to 60°. In particular, when the acute angle is 45°, the high strength and high modulus characteristics of the reinforcing fiber can be fully utilized. Therefore, the warp and weft reinforcing fibers of plain weave fabric 6 form a 45° angle with the rod body.

[0049] The composite material reducer housing 2 and rear cover housing 3 are manufactured by the following process:

[0050] I. Load distribution analysis of the shell and ply design

[0051] ① Load Analysis

[0052] Based on the load conditions of the shell during operation, the distribution of bending load force when the shell is subjected to the maximum load during bending is calculated in the finite element method ABAQUS. Basalt and carbon fiber are selected as fiber materials with high strength, high modulus, high fatigue resistance and low temperature resistance.

[0053] ②Layer design

[0054] According to the finite element analysis results, the inner surface of the reducer housing is padded with 30 layers at a 0° ply angle, the reinforcing ribs are padded with 50 layers at a ±45° ply angle, the cylindrical interface is padded with 40 layers at a ±45° ply angle, the remaining outer surface of the reducer housing is padded with 40 layers at a 0° / 45° / -45° / 0° ply angle, the rear cover housing is padded with 30 layers in a 0° / 45° / -45° ply sequence, and 10 reinforcing layers are padded at a ±45° ply angle at the openings, which can achieve the required strength.

[0055] II. Mold Design and Prepreg Preparation

[0056] ①Preparation of prepreg

[0057] According to the shape of the reducer housing 2 and the rear cover housing 3, the carbon fiber and basalt fiber fabrics are cut and prepared. The selected fabrics are all orthogonal fiber fabrics or unidirectional fiber fabrics. After the matrix resin and curing agent are mixed at a ratio of 100:33, the fibers are modified and mixed with the resin matrix in the form of silk, yarn, cloth, felt, etc. to make prepreg and preheated at 40°C in advance.

[0058] ② Mold design and pretreatment

[0059] Prepare a mold with an inner cavity shape corresponding to the reducer and the rear cover. The part of the mold cavity corresponding to the reducer housing 2 is the reducer housing cavity, and the part corresponding to the rear cover housing 3 is the rear cover housing cavity. In order to ensure the quality of the mold and the housing, use a clean white cotton cloth dipped in release agent to wipe the mold cavity thoroughly. At the same time, preheat the mold to 40℃-60℃.

[0060] III. Curing of the shell and post-curing treatment

[0061] ① Laying of prepreg

[0062] The preheated prepreg is laid in the mold cavity to form a fiber layup. The weight of the carbon fiber fabric laid in the reducer housing cavity and the rear cover housing cavity is 40% of the weight of the fiber layup. The basalt fiber fabric and carbon fiber fabric used are both orthogonal fabrics of ±45° and 0° / 90° or unidirectional fabrics laid in the corresponding molds, and the prepreg is ensured to fit the mold.

[0063] The fiber layup in the rear cover cavity consists of a mixed base layer, a transition layer, and a reinforcing layer stacked from top to bottom. The mixed base layer is formed by laying basalt prepreg and carbon fiber prepreg. The transition layer is formed by laying basalt prepreg. The reinforcing layer is formed by laying carbon fiber prepreg. At the same time, in order to reduce fiber breakage and stress concentration of composite materials at the opening, a reinforcing layer is set at the opening.

[0064] The base layer is formed by alternating layers of orthogonal basalt and carbon fiber prepreg from top to bottom at a 0° layup angle, with 5 layers of basalt and 5 layers of carbon fiber. The transition layer consists of 10 layers of unidirectional basalt prepreg laid at a 45° layup angle. The reinforcing layer consists of 10 layers of orthogonal carbon fiber prepreg laid at a -45° layup angle. The strengthening layer consists of 10 layers of orthogonal carbon fiber prepreg laid at ±45° layup angles.

[0065] The reducer housing has a relatively complex structure. When laying the prepreg, a separate laying method is used for the inner and outer surfaces. The outer surface of the reducer housing cavity is divided into reinforcing ribs, cylindrical interfaces, and the remaining outer surface. The remaining outer surface consists of a mixed base layer, a transition layer, a reinforcing layer, and a top layer, laid sequentially from top to bottom. The mixed base layer is formed by laying basalt prepreg and carbon fiber prepreg; the transition layer is formed by laying basalt prepreg; the reinforcing layer is formed by laying carbon fiber prepreg; and the top layer is formed by laying basalt and carbon fiber prepreg. The inner surface of the reducer housing is formed by laying basalt and carbon fiber.

[0066] The mixed underlayer is formed by alternating layers of orthogonal basalt and carbon fiber prepreg from top to bottom at a 0° layup angle, with 5 layers of basalt and 5 layers of carbon fiber. The transition layer consists of 10 layers of unidirectional basalt prepreg laid at a 45° layup angle. The reinforcing layer consists of 10 layers of unidirectional carbon fiber prepreg laid at a -45° layup angle. The top layer is formed by alternating layers of orthogonal basalt and carbon fiber prepreg from top to bottom at a 0° layup angle, with 5 layers of basalt and 5 layers of carbon fiber.

[0067] The reinforcing ribs are formed by laying 50 layers of orthogonal carbon fiber prepreg at a 45° layup angle from top to bottom.

[0068] The cylindrical joint is formed by laying 40 layers of orthogonal carbon fiber prepreg from top to bottom at a layup angle of ±45°.

[0069] The inner surface of the reducer housing cavity is formed by alternating layers of orthogonal basalt and carbon fiber prepreg from top to bottom at a 0° layup angle, with 15 layers of basalt and 15 layers of carbon fiber.

[0070] ② Shell curing

[0071] After the prepreg is laid, the male and female molds are quickly closed. After the molds are closed, they are cured for 120 minutes at a temperature of 120°C and a pressure of 400Pa using a hot press.

[0072] ③ Demolding and curing

[0073] After the composite material shell is cured and demolded, a basic cured product is obtained. Then, it is placed in a constant temperature chamber and cured at 120°C for 120 minutes.

[0074] ④ Shell connection and curing

[0075] After the inner surface, reinforcing ribs, cylindrical interfaces, and other outer surfaces of the reducer are demolded and cured, the metal internal splines are connected to the inner and outer surfaces of the housing using adhesive and hinges. The reinforcing ribs and cylindrical interfaces are connected to the splines and outer surfaces of the housing using adhesive. 3M DP460 structural adhesive is selected as the adhesive. Then, the reducer is placed in a constant temperature oven and cured at 120°C for 120 minutes.

[0076] ⑤ Casing polishing

[0077] After curing, it is deburred and polished.

[0078] The composite material half-shaft housing 4 is manufactured using the following process:

[0079] I. Load distribution analysis of the shell and ply design

[0080] ① Load Analysis

[0081] Based on the load conditions of the shell during operation, the distribution of torsional load force when the shell is subjected to the maximum load during torsion is calculated in the finite element method ABAQUS. Fiber materials with high strength, high modulus, high fatigue resistance and low temperature resistance are selected, such as glass fiber and carbon fiber.

[0082] ②Layer design

[0083] According to the finite element analysis results, the required strength can be achieved when the composite shell is laid in 20 layers at ±45°.

[0084] II. Preparation of the core mold and debugging of the winding machine

[0085] Prepare the corresponding core mold according to the shape and size of the designed half-shaft housing, and at the same time adjust the speed and angle required by the winding machine.

[0086] III. Curing of Prepreg Tape

[0087] ① Wrapping of prepreg tape

[0088] The reinforcing fibers are placed into the resin tank of the winding machine, and then resin is injected for mixing. The winding machine then winds the prepreg tape onto the mandrel at a speed of 10 m / min and with appropriate tension.

[0089] After the winding fibers are placed in the resin tank, acetone diluent needs to be added and mixed with the resin to prevent air bubbles from forming during winding and affecting the product. The winding fiber layup uses glass fiber and carbon fiber interleaved at ±45°, with 20 layers. During the winding process, drying is carried out simultaneously to remove solvent from the fiber strip, which can greatly reduce air bubbles and voids in the product.

[0090] ②Cure

[0091] The metal external spline is connected to the prepreg tape wrapped around the mandrel using an adhesive, and then placed in a constant temperature oven and cured at 120°C for 360 minutes.

[0092] IV. Post-curing treatment

[0093] After the curing process is completed, the shell is deburred and polished.

[0094] At this point, the composite material axle housing assembly has been completed.

[0095] Several experiments were conducted to test the relationship between materials, laying methods, and curing temperatures, as shown in the table below:

[0096]

[0097]

[0098] The above are merely specific embodiments of the present invention. Furthermore, terms such as "upper," "lower," "left," "right," and "middle" used in the present invention are for reference only and are not absolute limitations. Any non-substantial modifications made using the present invention shall be considered as infringing upon the protection scope of the present invention.

Claims

1. A manufacturing process for a composite material axle housing assembly for an automobile chassis, the axle housing comprising a reducer housing, a rear cover housing, and a half-shaft housing, characterized in that, The reducer housing and rear cover housing are manufactured using a prepreg molding process, while the half-shaft housing is manufactured using a winding process. The specific manufacturing steps are as follows: The molding process for the reducer housing and rear cover housing includes: Step A1: Analyze the load on the housing and design the plywood: Calculate the distribution of the maximum bending load force that the housing will bear when bending based on the load conditions of the reducer housing and the rear cover housing during operation, and select materials and plywood design to ensure that the required strength and stiffness are achieved. Step A2, Mold Design: Prepare a mold with an inner cavity shape corresponding to the reducer housing and the rear cover housing. The part of the mold cavity corresponding to the reducer housing is the reducer housing cavity, and the part corresponding to the rear cover housing is the rear cover housing cavity. Use a clean white cotton cloth dipped in release agent to wipe the mold cavity thoroughly. At the same time, preheat the mold to 40℃-60℃. Step A3, Prepreg preparation: Cut carbon fiber and basalt fiber fabrics according to the shape of the reducer housing and the rear cover housing, then mix the above fiber fabrics with resin to obtain prepreg and preheat at 40°C. Step A4, Shell Molding: The preheated prepreg is laid in the mold according to the design. The prepreg is impregnated, flows and fills the mold cavity under pressure. Finally, after pressure holding and cooling, it is demolded to complete the molding. Step A5, Post-molding processing: After demolding, the product is trimmed and punched to obtain the final product; The fabrication steps for the half-shaft housing are as follows: Step B1: Analyze the load on the shell and design the layup: Calculate the distribution of the maximum torsional force that the half shaft will bear during torsion based on the load conditions of the half shaft shell, select the fiber material and design the layup. Step B2, Mandrel Manufacturing and Winding Machine Assembly: Prepare steel mandrels of the required shape and size, and adjust the winding machine system; Step B3, Preparation of prepreg tape: Place the reinforcing fibers in the resin tank of the winding machine, and then inject resin to mix thoroughly with the fibers; Step B4, winding of prepreg tape: Under the control of the drive control system, the mandrel rotates at a predetermined speed, and the resin tank moves back and forth at a set speed, so that the prepreg tape is arranged in a spiral on the mandrel. Step B5, Curing of Prepreg Tape: Place the prepreg tape wrapped around the mandrel into an oven and set the temperature and time for curing; Step B6, Post-curing treatment; In step A2, the design of the connection between the reducer housing and the half shaft is added. A spline connection plus adhesive connection is adopted. There are a total of 8 keyways in the internal spline and three reinforcing ribs are set. 3M DP460 structural adhesive is selected as the adhesive. In step A4, 30 layers are laid inside the reducer housing at a 0° ply angle. The cylindrical interface, the outer surface reinforcing ribs, and the remaining outer surfaces are each laid with 40 layers at ply angles of ±45°, ±45°, and 0° / 45° / -45° / 0°. The rear cover housing is laid with 30 layers in a ply sequence of 0° / 45° / -45°. At the opening, 10 layers are laid at ±45°. In step B2, the end connection of the core mold adopts an external spline connection plus adhesive connection. The external spline has 8 keyways, and the adhesive selected is 3M DP460 structural adhesive.

2. A process for making a composite axle housing assembly for an automotive chassis as claimed in claim 1, wherein: In step A2, the mold adopts a rounded corner design; in step A3, epoxy resin is selected as the resin.

3. The process for making a composite axle housing assembly for an automotive chassis of claim 1, wherein: In step A4, the prepreg is preheated and immediately laid into the preheated mold.

4. The process for manufacturing a composite axle housing assembly for an automotive chassis of claim 1, wherein: In step B1, 30 layers are laid using a 45° / -45° layup.

5. The process for making a composite axle housing assembly for an automotive vehicle chassis of claim 1 wherein: In step B3, the temperature is controlled during the preparation of the prepreg to remove residual solvent while preventing the prepreg tape from curing and generating bubbles.

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