Axle tube assembly and manufacturing method thereof

Abstract

The invention provides a shaft tube assembly and a manufacturing method thereof. The shaft tube assembly comprises a motor, a shaft sleeve and a shaft sleeve, a spline is arranged at one end, close to the motor, of the shaft tube; and the transition connecting piece is made of aluminum alloy, the first end of the transition connecting piece is connected with the motor, and the second end of the transition connecting piece is in compression joint with the shaft tube to form interference fit. According to the shaft tube assembly, the transition connecting piece is made of the aluminum alloy material and is light in weight, the spline at the end of the shaft tube is in interference fit with the transition connecting piece, interference exists after the spline and the transition connecting piece are assembled, teeth on the spline generate plastic deformation to be tightly attached to the shaft tube, tight connection of the shaft tube and the transition connecting piece is achieved, and the connection reliability is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of vehicle drive axles, and particularly to a shaft tube assembly and a manufacturing method thereof. Background Art

[0002] The working principle of an electric drive axle is to drive the vehicle wheels to rotate by using an electric motor. Compared with a traditional internal combustion engine drive axle, the electric drive axle omits components such as an engine, a transmission, and a drive shaft, and directly controls the rotation speed of the wheels through the electric motor, thereby controlling the driving direction and speed of the vehicle. The stator and rotor in the electric motor are relatively heavy, and the electric drive axle is usually arranged below the vehicle's spring. The increase in system weight leads to an increase in the unsprung weight of the vehicle, resulting in a decline in vehicle performance. For this reason, the electric drive axle adopts a lightweight design. The motor housing is mostly made of aluminum alloy material, and the shaft tubes on both sides of the motor bear the load transmitted by the vehicle leaf spring. Therefore, the shaft tubes are usually made of steel material.

[0003] In the prior art, as Figure 1 shown, a transition connecting piece 3 is provided between the electric motor 1 and the shaft tube 2. The material of the transition connecting piece is steel. One end of the transition connecting piece (the right end in the figure) is connected to the motor housing through bolts and positioning pins, and the other end of the transition connecting piece (the left end) is sleeved on the shaft tube and welded to the shaft tube.

[0004] In the process of implementing the present invention, the inventors found that there are at least the following problems in the prior art: the material of the transition connecting piece is steel, which is heavy and affects vehicle controllability; the transition connecting piece is connected to the motor housing by bolts, and sealant also needs to be applied to maintain the motor seal, resulting in low processing efficiency; in addition, in the case of a large temperature difference between two different materials, the bolt connection may become loose due to thermal expansion and contraction, reducing the reliability of the motor. Summary of the Invention

[0005] The present invention aims to solve at least one of the technical problems in the related art to some extent.

[0006] To this end, an object of the present invention is to provide a shaft tube assembly with relatively light weight and high reliability and a manufacturing method thereof.

[0007] To achieve the above object, a shaft tube assembly is provided in the first aspect of the present invention, including:

[0008] An electric motor;

[0009] A shaft tube, on which a spline is provided at one end close to the electric motor;

[0010] A transition connecting piece, the material of the transition connecting piece is aluminum alloy, the first end of the transition connecting piece is connected to the electric motor, and the second end of the transition connecting piece is press-fitted with the shaft tube to form an interference fit.

[0011] According to the shaft tube assembly of the present invention, by making the transition connecting piece of aluminum alloy material, the mass is relatively light. The spline at the end of the shaft tube is in interference fit with the transition connecting piece. After the two are assembled, there is an interference amount, and the teeth on the spline produce plastic deformation and are closely attached to the shaft tube, realizing the tight connection between the shaft tube and the transition connecting piece and improving the connection reliability.

[0012] According to an embodiment of the present invention, the motor includes a motor housing. The transition connecting piece includes an integrally formed base and a connecting portion. The base is configured as the end cover of the motor. The base is detachably connected to the motor housing, and the connecting portion is press-fitted with the spline.

[0013] According to an embodiment of the present invention, a light hole is provided in the middle of the connecting portion. The light hole is press-fitted with the spline, and the inner diameter of the light hole is smaller than the outer diameter of the circle where the tooth tops of the spline are located.

[0014] According to an embodiment of the present invention, the distance from the inner wall of the light hole to the root of the spline is one-fourth to one-half of the height of the spline.

[0015] According to an embodiment of the present invention, a chamfer is provided at one end of the shaft tube where the transition connecting piece is press-fitted.

[0016] According to an embodiment of the present invention, the module of the spline is 0.2 to 0.35.

[0017] According to an embodiment of the present invention, the transition connecting piece further includes a plurality of support rods. The support rods are arranged around the connecting portion. One end of the support rod is connected to the base, and the other end of the support rod is connected to the connecting portion.

[0018] The second aspect of the present invention provides a manufacturing method of a shaft tube assembly, including:

[0019] Connect one end of the transition connecting piece to the motor, wherein the material of the transition connecting piece is aluminum alloy, and a light hole is provided at the end of the transition connecting piece far from the motor;

[0020] Press-fit the shaft tube with the light hole to form an interference fit, wherein a spline is provided at one end of the shaft tube close to the motor.

[0021] According to the manufacturing method of the shaft tube assembly of the present invention, by making the transition connecting piece of aluminum alloy material, the mass is relatively light. The spline at the end of the shaft tube is in interference fit with the transition connecting piece. After the two are assembled, there is an interference amount, and the teeth on the spline produce plastic deformation and are closely attached to the shaft tube, realizing the tight connection between the shaft tube and the transition connecting piece and improving the connection reliability.

[0022] According to an embodiment of the present invention, the length of the shaft tube pressed into the light hole is not less than 120 mm.

[0023] According to an embodiment of the present invention, it further includes:

[0024] Vertically place the motor and the transition connecting member, heat-treat the transition connecting member, align the spline-end of the shaft tube with the light hole, and press the shaft tube into the light hole using a press.

[0025] Additional aspects and advantages of the present invention will be given in part in the following description, become apparent in part from the following description, or be learned through the practice of the present invention. Description of the Drawings

[0026] By reading the following detailed description of the preferred embodiments, various other advantages and benefits will become clear to those of ordinary skill in the art. The drawings are only for the purpose of showing the preferred embodiments and are not considered to be a limitation of the present invention. Moreover, throughout the drawings, the same reference numerals are used to represent the same components. Among them:

[0027] Figure 1 is a schematic structural diagram of a shaft tube assembly in the prior art.

[0028] Figure 2 is a schematic structural diagram of a shaft tube assembly proposed in an embodiment of the present invention.

[0029] Figure 3 is a schematic structural diagram of a shaft tube related to an embodiment of the present invention.

[0030] Figure 4 is Figure 3 a partial enlarged schematic diagram at position A in

[0031] Figure 5 is Figure 2 a cross-sectional view taken along line A-A in

[0032] Figure 6 is a schematic flow diagram of a manufacturing method of a shaft tube assembly proposed in an embodiment of the present invention.

[0033] Description of the Reference Numerals in the Drawings:

[0034] 1 - motor, 2 - shaft tube, 3 - transition connecting member, 21 - spline, 22 - chamfer, 31 - connecting portion, 32 - support rod, 33 - base. Detailed Embodiments

[0035] Embodiments of the present invention will be described in detail below. Examples of the embodiments are shown in the accompanying drawings, where the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the accompanying drawings are exemplary and are only used to explain the present invention and should not be construed as a limitation of the present invention. On the contrary, the embodiments of the present invention include all variations, modifications and equivalents falling within the spirit and scope of the appended claims.

[0036] Reference is made below Figures 2 to 5 , to describe a shaft tube assembly according to an embodiment of the present invention.

[0037] Referring to Figures 2 to 5 , a shaft tube assembly according to an embodiment of the present invention includes a motor 1, a shaft tube 2 and a transition connecting member 3.

[0038] The motor 1 functions to drive the vehicle in a new energy vehicle. The specific type of the motor is set according to actual needs and is not limited thereto. By way of example, the motor 1 may be a permanent magnet synchronous motor, an induction motor, a brushless DC motor, etc. The shaft tube 2 is provided with a spline 21 at one end close to the motor 1. The shaft tube 2 is a part of the transmission system and can support the drive shaft and protect the internal transmission components. In order to bear heavy loads, the shaft tube 2 is generally made of high-strength steel or alloy steel. The specific type of the spline on the shaft tube 2 is set according to actual needs and is not limited thereto. By way of example, the cross-section of the spline may be rectangular or triangular. The transition connecting member 3 is made of aluminum alloy. The first end of the transition connecting member 3 is connected to the motor 1, and the second end of the transition connecting member 3 is press-fitted with the shaft tube 2 to form an interference fit.

[0039] The transition connecting member 3, as an end cover of the motor, can be detachably connected to the housing of the motor 1, such as by bolt fixing, snap fixing, etc. The second end of the transition connecting member 3 has a round hole and is press-fitted with the shaft tube 2. During the press-fitting process, the transition connecting member 3 undergoes plastic deformation under the action of external force and combines with the spline 21, and the round hole generates a tightening force on the spline to achieve a tight connection between the two. The inner wall of the round hole can be a smooth surface or a rough surface.

[0040] For the shaft tube assembly according to an embodiment of the present invention, by making the transition connecting member of aluminum alloy material, the mass is lighter. The spline at the end of the shaft tube and the transition connecting member are in interference fit. After the two are assembled, there is an interference amount, and the teeth on the spline undergo plastic deformation and are closely attached to the shaft tube, achieving a tight connection between the shaft tube and the transition connecting member and improving the connection reliability.

[0041] Combined with Figure 2 and Figure 5As shown, in some embodiments, the motor 1 includes a motor housing. The transition connector 3 includes an integrally formed base 33 and a connecting portion 31. The base 33 is configured as an end cover of the motor. The base 33 is detachably connected to the motor housing, and the connecting portion 31 is press-fitted with the spline 21. For example, the base 33 and the motor housing are connected by bolts. When the base 33 is configured as the end cover of the motor, the number of parts can be reduced, it is easy to disassemble and assemble, and the workload of maintenance is reduced. A light hole is provided in the middle of the connecting portion 31. The light hole is press-fitted with the spline 21. The inner diameter of the light hole is smaller than the outer diameter of the circle where the tooth crest of the spline 21 is located, thereby forming an interference fit to ensure the stability and reliability of the connection and further realizing efficient power transmission.

[0042] In one example, the distance from the inner wall of the light hole to the root of the spline 21 is one-fourth to one-half of the height of the spline 21. This solution is beneficial for tight fitting and avoids local stress concentration. The module of the spline 21 is set according to actual needs, and no specific limitation is made here. For example, the module of the spline 21 is 0.2 to 0.35, which is structurally compact while ensuring sufficient mechanical strength.

[0043] As Figure 4 shown, a chamfer 22 is provided at one end of the shaft tube 2 where the transition connector 3 is press-fitted. The chamfer angle is set according to actual needs. Generally, the chamfer angle range is 15 degrees to 45 degrees. It not only removes burrs during the processing, but also makes it easier for the shaft tube 2 to be inserted into the transition connector 3, reducing the assembly difficulty.

[0044] In some embodiments, in combination with Figure 2 and Figure 5 shown, the transition connector 3 further includes a plurality of support rods 32. The support rods 32 are arranged around the connecting portion 31. One end of the support rod 32 is connected to the base 33, and the other end of the support rod 32 is connected to the connecting portion 31. The number of support rods 32 is set according to actual needs and is not limited here. The support rods 32 can enhance the connection strength between the base 33 and the connecting portion 31.

[0045] In combination with Figures 2 to 6 shown, an embodiment of the present invention also proposes a manufacturing method for a shaft tube assembly. The implementation process of this method includes the following steps:

[0046] Step S102, connect one end of the transition connector 3 to the motor 1, wherein the material of the transition connector 3 is aluminum alloy, and a light hole is provided at the end of the transition connector 3 away from the motor 1.

[0047] In this embodiment, the use of aluminum alloy as the material of the transition connector 3 can achieve the lightweight of the entire shaft tube assembly. The transition connector 3 is detachably connected to the motor 1, improving the convenience of maintenance. The transition connector 3 is configured as an end cover of the motor at the end close to the motor 1, which can reduce the number of components of the entire shaft tube assembly.

[0048] Step S104, press-fit the shaft tube 2 and the optical hole to form an interference fit, wherein the shaft tube 2 is provided with a spline 21 at one end close to the motor 1.

[0049] In this embodiment, the inner diameter of the optical hole is smaller than the outer diameter of the circle where the tooth tips of the spline 21 are located, thereby forming an interference fit to ensure the stability and reliability of the connection and further realizing efficient power transmission. The length of the shaft tube 2 pressed into the optical hole is set according to actual needs, and there is no limitation on this. For example, the length of the shaft tube 2 pressed into the optical hole is not less than 120 mm, which can achieve better connection strength and better transmission effect.

[0050] According to the manufacturing method of the shaft tube assembly of the embodiment of the present invention, by making the transition connector from an aluminum alloy material, the quality is relatively light. The spline at the end of the shaft tube and the transition connector form an interference fit. After the two are assembled, there is an interference amount, and the teeth on the spline produce plastic deformation and are closely attached to the shaft tube, realizing the tight connection between the shaft tube and the transition connector and improving the connection reliability.

[0051] In some embodiments, the manufacturing method of the shaft tube assembly further includes:

[0052] Step S103, place the motor 1 and the transition connector 3 vertically, heat-treat the transition connector 3, align the end of the shaft tube 2 with the spline 21 to the optical hole, and use a press to press the shaft tube 2 into the optical hole.

[0053] In this embodiment, heating the transition connector 3 can cause the optical hole to expand thermally. Start the press and gradually increase the pressure to smoothly press the shaft tube 2 into the optical hole. During the entire pressing process, closely observe the pressing depth and the actual pressure value to avoid damaging the parts.

[0054] It should be noted that in the description of the present invention, the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance. In addition, in the description of the present invention, unless otherwise specified, the meaning of "a plurality" is two or more.

[0055] In the present invention, unless otherwise clearly defined and limited, the terms "installation", "connection", "connection", "fixation", etc. should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection, an electrical connection, or communication with each other; it can be directly connected, or indirectly connected through an intermediate medium. It can be the internal communication of two components or the interaction relationship between two components, unless otherwise clearly defined. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0056] In the present invention, unless otherwise clearly specified or limited, the first feature being "on" or "under" the second feature may mean that the first and second features are in direct contact, or the first and second features are indirectly in contact through an intermediate medium. Moreover, the first feature being "above", "over" and "on top of" the second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the horizontal height of the first feature is higher than that of the second feature. The first feature being "under", "below" and "beneath" the second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the horizontal height of the first feature is less than that of the second feature.

[0057] In the description of the present invention, the orientation or positional relationship indicated by the terms "left", "right", "front", "rear", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention.

[0058] Any process or method description shown in a flowchart or described in other ways herein may be understood to represent a module, segment, or portion of code including one or more executable instructions for implementing a specific logical function or process. The scope of the preferred embodiments of the present invention includes additional implementations, where the functions may be executed in a substantially simultaneous manner or in a reverse order according to the involved functions, rather than in the order shown or discussed. This should be understood by those skilled in the art to which the embodiments of the present invention pertain.

[0059] In the description of this specification, the descriptions referring to terms such as "one embodiment", "some embodiments", "example", "specific example", or "some examples", etc. mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in a suitable manner in any one or more embodiments or examples.

[0060] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as a limitation of the present invention. Those of ordinary skill in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present invention.

Claims

1. A shaft tube assembly, characterized in that: include: Motor (1); A shaft tube (2), wherein a spline (21) is provided on one end of the shaft tube (2) close to the motor (1); A transition connector (3), wherein the material of the transition connector (3) is aluminum alloy, the first end of the transition connector (3) is connected to the motor (1), and the second end of the transition connector (3) is crimped to the shaft tube (2) to form an interference fit.

2. The shaft tube assembly according to claim 1, characterized in that: The motor (1) comprises a motor housing, and the transition connector (3) comprises an integrally formed base (33) and a connecting portion (31), wherein the base (33) is configured as an end cover of the motor, the base (33) is detachably connected to the motor housing, and the connecting portion (31) is crimped to the spline (21).

3. The shaft tube assembly according to claim 2, characterized in that: A light hole is provided in the middle of the connecting portion (31), the light hole is crimped to the spline (21), and the inner diameter of the light hole is smaller than the outer diameter of the circle where the tooth top of the spline (21) is located.

4. The shaft tube assembly according to claim 3, characterized in that: The distance from the inner wall of the light hole to the root of the spline (21) is one quarter to one half of the height of the spline (21).

5. The shaft tube assembly according to claim 1, characterized in that: The shaft tube (2) is provided with a chamfer (22) on one end thereof which is crimped to the transition connector (3).

6. The shaft tube assembly according to claim 3, characterized in that: The module of the spline (21) is 0.2 to 0.

35.

7. The shaft tube assembly according to claim 3, characterized in that: The transition connector (3) further comprises a plurality of support rods (32), wherein the support rods (32) are arranged around the connecting portion (31), one end of the support rod (32) is connected to the base (33), and the other end of the support rod (32) is connected to the connecting portion (31).

8. A method for manufacturing an axle tube assembly, characterized in that: include: Connecting one end of a transition connector (3) to a motor (1), wherein the transition connector (3) is made of aluminum alloy, and a light hole is provided at one end of the transition connector (3) away from the motor (1); The shaft tube (2) and the light hole are crimped to form an interference fit, wherein a spline (21) is provided on one end of the shaft tube (2) close to the motor (1).

9. The method for manufacturing the shaft tube assembly according to claim 8, characterized in that: The length of the shaft tube (2) pressed into the light hole is not less than 120 mm.

10. The method for manufacturing the shaft tube assembly according to claim 8, characterized in that: Also includes: The motor (1) and the transition piece (3) are placed vertically, the transition piece (3) is heated, one end of the shaft tube (2) having the spline (21) is aligned with the light hole, and the shaft tube (2) is pressed into the light hole using a press.

Images