A lightweight transmission shaft and a method for manufacturing the same

Abstract

A lightweight transmission shaft comprises a shaft tube, a universal joint fork, a spline sleeve, and a spline shaft fork, wherein one end of the shaft tube is connected to the universal joint fork, and the other end is connected to the spline sleeve, the spline sleeve is connected to the spline shaft fork via a spline, the shaft tube comprises an inner layer of an aluminum alloy seamless tube and an outer layer of a carbon fiber / glass fiber composite material, the thickness ratio of the outer layer composite material to the aluminum alloy seamless tube is 1:2-8, and the ratio of carbon fiber to glass fiber in the composite material is 1:1-6; the aluminum alloy seamless tube is fixed to the universal joint fork and the spline sleeve by friction welding, and the composite material is connected to the aluminum alloy parts by bonding and screwing. The multi-material hybrid structure transmission shaft provided by the present invention has many advantages such as lightweight, high torsional strength, low design redundancy, short process, etc., and is suitable for mass production and the automotive industry with high cost sensitivity.

Description

Technical Field

[0001] The invention relates to the field of automobile transmission shafts, and in particular to a lightweight transmission shaft and a preparation method thereof. Background Art

[0002] As an important component for transmitting power, drive shafts are widely used in many fields such as automobiles, ships, and engineering machinery. As the global energy crisis becomes increasingly serious and energy conservation and emission reduction policies are gradually tightened, lightweighting has become one of the best solutions to solve the above problems. However, the chain reactions caused by lightweighting must be taken into account in the process of process, cost, stability, etc. Although the traditional steel drive shaft has mature technology and low cost, it is currently facing a series of problems such as heavy weight, easy corrosion, and noise; aluminum alloy drive shafts are becoming one of the products that the industry is competing to develop, with advantages such as light weight, corrosion resistance, and low cost. However, the overall strength of aluminum alloys is insufficient and the performance loss of joints after welding has become an obstacle to its development and application; carbon fiber can basically meet the performance requirements of drive shaft products. The wall thickness of the carbon fiber shaft tube directly affects its stiffness and material cost, and it is difficult to take both into account. In addition, the high price of carbon fiber drive shafts makes OEMs and customers discouraged.

[0003] Various materials such as steel, aluminum alloy, and carbon fiber have their own advantages and disadvantages. Therefore, it is necessary to design a multi-material hybrid structure transmission shaft and a corresponding reliable connection solution to ensure that the price is within an acceptable range while achieving lightweight and meeting performance requirements. Summary of the invention

[0004] In view of the problems of complex process, joint performance loss, high cost, etc. in the production and use of the above-mentioned existing transmission shafts, the present invention discloses a lightweight transmission shaft and preparation technology. By rationally designing and optimizing the transmission shaft structure, the distribution ratio of various materials, and the diversified connection methods, a high-quality, low-cost, and mass-produced lightweight transmission shaft is obtained.

[0005] To achieve the above-mentioned purpose, in a first aspect, the present invention provides a lightweight transmission shaft, characterized in that it includes a shaft tube, a universal joint fork, a spline sleeve, and a spline shaft fork, wherein one end of the shaft tube is connected to the universal joint fork, and the other end is connected to the spline sleeve, and the spline sleeve is connected to the spline shaft fork through a spline, and the shaft tube includes an inner layer of an aluminum alloy seamless tube and an outer layer of a carbon fiber / glass fiber composite material, the thickness ratio of the outer layer composite material to the aluminum alloy seamless tube is 1:2-8, and the ratio of carbon fiber to glass fiber in the composite material is 1:1-6; the aluminum alloy seamless tube is fixed to the universal joint fork and the spline sleeve by friction welding, and the composite material is connected to the aluminum alloy parts by bonding and screwing.

[0006] Furthermore, the threaded connection is made by using a threaded bushing and a top screw.

[0007] Furthermore, the thickness ratio of the composite material to the aluminum alloy seamless tube is 1:3, and the ratio of carbon fiber to glass fiber in the composite material is 1:2.

[0008] In a second aspect, the present invention provides a method for preparing a lightweight transmission shaft, comprising the following steps:

[0009] Step 1: Forge the spline sleeve and universal joint fork, and perform solid solution + pre-aging treatment; forge the spline shaft fork, perform solid solution + under-aging treatment, and then coat it with nylon after processing to the designed specifications and dimensions, reverse extrude the aluminum alloy shaft tube and process it to a fixed length.

[0010] Step 2: After the threaded bushing and the top wire are coated with glue, they are successively installed on the pre-welded parts of the spline sleeve and the universal joint fork.

[0011] Step three, the two ends of the aluminum alloy shaft tube are connected to the universal joint fork and the spline sleeve respectively through the friction welding process. After artificial aging as a whole, the outer flange at the welding joint is turned flat.

[0012] Step 4: Composite material winding molding, using the aluminum alloy shaft tube as the core shaft, cross-winding carbon fiber / glass fiber at a ratio of 1:1 to 6, with a prestress of 45-65 MPa and a winding angle of 45°.

[0013] Step five, solidifying the wound transmission shaft.

[0014] Furthermore, the nylon coating in step 1 is heated by electromagnetic induction, heated to 190-220° C. and kept warm for 3-15 minutes.

[0015] Furthermore, the curing temperature in step five is 95-125° C. and the curing time is 100-200 min.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] While ensuring that the shaft tube has sufficient torsional strength and rigidity, it can also achieve a greater degree of lightweight than an all-aluminum drive shaft, while the cost will not change much. It can not only ensure sufficient connection strength and fatigue performance, but also retain the beautiful and neat appearance of the drive shaft. The heat treatment method of solid solution → friction welding → artificial aging can not only make up for the performance loss of the welding joint caused by friction welding, but also avoid the deformation problem caused by the overall T6 treatment after welding. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The present invention will be described in further detail below by means of examples and with reference to the accompanying drawings.

[0019] Figure 1 It is a schematic structural diagram of the multi-material lightweight transmission shaft of the present invention.

[0020] Figure 2 It is an exploded view of the multi-material lightweight transmission shaft of the present invention.

[0021] Figure 3 It is an enlarged view of the multi-material lightweight transmission shaft joint of the present invention.

[0022] In the figure, 1 is universal joint fork, 2 is inner layer of shaft tube, 3 is outer layer of shaft tube, 4 is spline sleeve, 5 is spline shaft fork, 6 is threaded bushing, and 7 is top screw. DETAILED DESCRIPTION

[0023] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0024] The terms "first", "second", "third", "fourth", etc. in the specification and claims of this application and the drawings are used to distinguish different objects, rather than to describe a specific order. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, product or device that includes a series of steps or units is not limited to the listed steps or units, but optionally includes steps or units that are not listed, or optionally includes other steps or units inherent to these processes, methods, products or devices.

[0025] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0026] like Figure 1As shown, a multi-material lightweight transmission shaft comprises: a universal joint fork 1, a shaft tube, a spline sleeve 4, and a spline shaft fork 5, wherein one end of the shaft tube is connected to the universal joint fork 1, and the other end is connected to the spline sleeve 4, the spline sleeve 4 and the spline shaft fork 5 are connected by splines, and the connection method is bonding + screw connection, the inner layer 2 of the shaft tube is an aluminum alloy seamless tube, and the outer layer 3 of the shaft tube is a carbon fiber / glass fiber composite material, wherein the thickness ratio of the outer layer composite material to the inner layer aluminum alloy seamless tube is 1:2-8, and the ratio of carbon fiber to glass fiber in the composite material is 1:1-6. Preferably, the thickness ratio of the composite material to the aluminum alloy seamless tube is 1:3, and the ratio of carbon fiber to glass fiber in the composite material is 1:2. In this way, firstly, it is ensured that the shaft tube has sufficient torsional strength and rigidity, and secondly, it can achieve a greater degree of lightweight than an all-aluminum transmission shaft, and at the same time, the cost will not change too much.

[0027] The aluminum alloy seamless pipe is friction welded with the universal joint fork 1 and the spline sleeve 4, and the composite material and the aluminum alloy parts are bonded and screwed. The screw connection uses a threaded bushing 6 + a top screw 7, which can ensure sufficient connection strength and fatigue performance while retaining the beautiful and neat appearance of the transmission shaft.

[0028] In this embodiment, the lightweight transmission shaft of the present invention is manufactured by the following method:

[0029] ① Forge spline sleeve 4 and universal joint fork 1, and perform solid solution + pre-aging treatment on them, and then process them to the designed specifications and dimensions; forge spline shaft fork 5, and perform solid solution + under-aging treatment, and then perform nylon coating after processing to the designed specifications and dimensions. The heating during the nylon coating process adopts electromagnetic induction heating, 190~220℃ / insulation for 3~15min; reduce the sensitivity of T6 state aluminum alloy (aluminum alloy after solid solution + artificial aging treatment) parts to reheating after heat treatment to avoid their performance loss. Reversely extrude aluminum alloy shaft tube and process to size.

[0030] ② After being coated with glue, the threaded bushing 6 and the top screw 7 are successively installed on the pre-welded parts of the spline sleeve 4 and the universal joint fork 1.

[0031] ③ The two ends of the aluminum alloy shaft tube are respectively connected to the universal joint fork 1 and the spline sleeve 4 by a friction welding process. After artificial aging as a whole, the outer flange at the welding joint is turned flat.

[0032] ④ Composite material winding molding, with aluminum alloy shaft tube as the core shaft, carbon fiber / glass fiber cross-winding at a ratio of 1:1 to 6, prestressing 45-65MPa, and winding angle of 45°.

[0033] ⑤ Curing the wound transmission shaft at a temperature of 95-125°C for 100-200 minutes.

[0034] Compared with the prior art, the present invention has the following beneficial effects:

[0035] While ensuring that the shaft tube has sufficient torsional strength and rigidity, it can also achieve a greater degree of lightweight than an all-aluminum drive shaft, while the cost will not change much. It can not only ensure sufficient connection strength and fatigue performance, but also retain the beautiful and neat appearance of the drive shaft. The heat treatment method of solid solution → friction welding → artificial aging can not only make up for the performance loss of the welding joint caused by friction welding, but also avoid the deformation problem caused by the overall T6 treatment after welding.

Claims

1. A method for preparing a lightweight transmission shaft, characterized in that: The preparation method is applied to the preparation of a lightweight transmission shaft, wherein the lightweight transmission shaft comprises a shaft tube, a universal joint fork (1), a spline sleeve (4), and a spline shaft fork (5), wherein one end of the shaft tube is connected to the universal joint fork (1), and the other end is connected to the spline sleeve (4), and the spline shaft fork (5) is connected to the spline shaft fork (5) via a spline, and the shaft tube comprises a shaft tube inner layer (2) made of an aluminum alloy seamless tube and a shaft tube outer layer (3) made of a carbon fiber / glass fiber composite material, wherein the thickness ratio of the composite material of the shaft tube outer layer (3) to the aluminum alloy seamless tube is 1:2-8, and the ratio of carbon fiber to glass fiber in the composite material is 1:1-6; the aluminum alloy seamless tube is fixed to the universal joint fork (1) and the spline sleeve (4) by friction welding, and the composite material is connected to the aluminum alloy parts by bonding and screwing; The preparation method comprises the following steps: Step 1: forging a spline sleeve (4) and a universal joint fork (1), and performing a solid solution + pre-aging treatment; forging a spline shaft fork (5), and performing a solid solution + under-aging treatment, and coating the spline shaft fork (5) with nylon after processing to the designed specification size, and reversely extruding an aluminum alloy shaft tube and processing the shaft tube to a fixed length; Step 2: After the threaded bushing (6) and the top screw (7) are coated with glue, they are successively installed on the pre-welded parts of the spline sleeve (4) and the universal joint fork (1); Step 3: The two ends of the aluminum alloy shaft tube are respectively connected to the universal joint fork (1) and the spline sleeve (4) by a friction welding process, and after artificial aging of the whole, the outer flange at the welding joint is turned flat; Step 4: Composite material winding molding, using the aluminum alloy shaft tube as the core shaft, cross-winding carbon fiber / glass fiber at a ratio of 1:1 to 6, with a prestress of 45-65MPa and a winding angle of 45°; Step 5: solidify the wound transmission shaft.

2. The method for preparing a lightweight transmission shaft according to claim 1, characterized in that: The nylon coating in step 1 is heated by electromagnetic induction, heated to 190-220° C. and kept warm for 3-15 minutes.

3. The method for preparing a lightweight transmission shaft according to claim 1, characterized in that: The curing temperature in step 5 is 95-125° C. and the curing time is 100-200 min.

Images