A machining process for a drive shaft

Abstract

The application relates to the field of metal processing, and provides a transmission shaft processing technology, the transmission shaft comprising a shaft body and a fixing shaft; the transmission shaft is composed of the shaft body and the fixing shaft, can be connected and locked with an internal thread through a first connecting part, or can be connected and locked with an external thread through a second connecting part. Thus, the shaft body can be locked by two fixing shafts, or multiple shaft bodies can be connected and used, and the use flexibility is high. A parabolic groove and a transition arc surface are arranged on the shaft body, the parabolic groove and the transition arc surface can be sleeved with a power output shaft or a connecting shaft. The parabolic groove is designed to have different curvatures, so that the structure fitted in the parabolic groove has a top resistance force towards the transition arc surface, and the structure of the transition arc surface has a top resistance force towards the parabolic groove. After assembly, if the transmission force is too large, the transmission shaft will slip, and the purpose of overload prevention is achieved.

Description

Technical Field

[0001] The present invention relates to the field of metal processing not included in other categories, and specifically to a processing technology for a transmission shaft. Background Art

[0002] The drive shaft is a high-speed, low-support rotating body, so its dynamic balance is crucial. Generally, drive shafts undergo dynamic balancing tests and adjustments on a balancing machine before leaving the factory. In front-engine, rear-wheel-drive vehicles, this shaft transmits the transmission's rotation to the final drive. It can consist of multiple sections, each connected by a universal joint.

[0003] Damage, wear, deformation, and loss of dynamic balance in the drive shaft can cause unusual noises and vibrations while the vehicle is in motion, and in severe cases, can lead to damage to related components. A "dinging" sound may be heard when starting or accelerating rapidly, and the components may feel loose. If the problem isn't with the drive axle gears, then the drive shaft is clearly loose.

[0004] Therefore, the design of the transmission shaft requires a high degree of fit precision to ensure smooth power transmission. If the transmission shaft is overloaded, it will wear and break, posing a safety issue. Summary of the Invention

[0005] The purpose of the present invention is to provide a processing technology for a transmission shaft, aiming to improve the problem that the existing transmission shaft has low self-protection performance or no self-protection after being overloaded.

[0006] To achieve the above-mentioned object, the present invention adopts the following technical solutions: a process for processing a transmission shaft, the transmission shaft comprising a shaft body and a fixed shaft;

[0007] The processing technology of the shaft body includes the following steps:

[0008] One end of the shaft blank is processed to form a cylindrical clamping section for centering clamping;

[0009] After centering and clamping, the shaft blank is turned to form a rough workpiece of three stepped shafts with decreasing or increasing steps;

[0010] A transmission groove is cut in the middle of the intermediate stepped shaft;

[0011] Turn or tap the external thread on the smallest step shaft;

[0012] A circular shaft segment, a parabolic groove, and a transition arc surface are sequentially machined on the maximum step shaft starting from the shaft end. The curvature of the parabolic groove from the circular shaft segment to the vertex of the parabola is greater than the curvature from the vertex of the parabola to the transition arc surface. The transition arc surface is located at the notch of the parabolic groove and extends to the middle step shaft and is curved outward.

[0013] Drill a blind hole on the end face where the largest stepped shaft is located and machine the internal thread;

[0014] The processing technology of the fixed shaft includes the following steps:

[0015] The fixed shaft blank is cut to form a first connecting portion that is threadedly engaged with the internal thread of the blind hole of the shaft body.

[0016] After the first connecting portion is assembled and connected with the blind hole internal thread of the shaft body, a locking portion having an arc-shaped surface is cut and processed on the fixed shaft blank located at the other end of the first connecting portion;

[0017] Drilling a blind hole on the end surface of the lock portion, and cutting and processing from the outside to the inside along the blind hole to form a sleeve portion for engaging with the side wall of the transmission groove and a second connecting portion for threaded engagement with the external thread;

[0018] The shaft body and the fixed shaft clamping section are removed, cut, and then polished to complete the processing.

[0019] Furthermore, the processing equation of the parabolic curve of the parabolic groove is:

[0020] X 2 =2pY, or, Y 2 =2pX;

[0021] Wherein, p is the focal coordinate value, 0<p, and X represents the X-axis value, and Y represents the Y-axis value; when 2pY or 2pX takes a positive value, the opening of the parabola is toward the positive direction of the coordinate axis; when 2pY or 2pX takes a negative value, the opening of the parabola is toward the negative direction of the coordinate axis; the parabolic groove is processed according to the processing equation.

[0022] Furthermore, the transmission groove processing step of the intermediate stepped shaft includes:

[0023] A transmission groove is cut out, and shaft shoulders on both sides are reserved; a transition chamfering process is performed between the transmission groove and the shaft shoulders by using an external circular cutter.

[0024] Furthermore, the external thread processing step of the minimum step shaft includes:

[0025] Cutting a cutting groove at the connection position between the minimum step shaft and the shaft shoulder by a cutting knife;

[0026] The external thread is machined by a turning tool or a thread turning tool.

[0027] Further, the blind hole is further provided with an arc surface between the internal thread and the port of the blind hole; the arc surface is machined along the inner diameter of the port after the drilling depth of the blind hole is machined; the thread groove is machined on the bottom surface of the blind hole, and the internal thread with the same depth as the thread groove is machined.

[0028] Further, the machining process steps of the lock head are as follows: the machining of the first connecting part is completed first, and then the machining of the lock head is performed after the threaded locking with the shaft body, so that the maximum diameter of the lock head is the same as the maximum diameter of the shaft body.

[0029] Further, the machining process steps of the maximum stepped shaft of the shaft body are as follows:

[0030] The 35° external circle rhombus tool is used for rough machining, and the R2 ball head tool is used for multiple fine machining; the spindle speed of the rough machining is 800 rpm, and the feed speed is 150 mm / min; the spindle speed of the fine machining is 1500 rpm, and the feed speed is 100 mm / min.

[0031] Further, the machining process steps of the transmission groove are as follows:

[0032] The rough blank annular groove is machined by cutting with a machining allowance; the side wall and the bottom corner arc transition surface of the rough blank annular groove are symmetrically machined by using the R2 ball head tool, and the two symmetric side walls form an included angle of 40°; the machining of the trapezoidal structure of the transmission groove is completed.

[0033] Further, the machining precision grade of the shaft body and the fixed shaft is at least IT8 level.

[0034] After the above technical solution is adopted, the present application has the following advantages compared with the background art:

[0035] 1. The transmission shaft is composed of a shaft body and a fixed shaft, and can be connected and locked with the internal thread through the first connecting part, or can be connected and locked with the external thread through the second connecting part. In this way, the two ends of the shaft body and the fixed shaft can be connected and locked, and the shaft body can be used by being connected and locked by two fixed shafts or by being connected and locked by multiple fixed shafts, so that the use flexibility is high.

[0036] 2. The shaft is designed with a parabolic groove and a transition arc surface, which allows for socketing with the power output shaft or docking shaft. The varying curvature of the parabolic groove ensures that the structure engaged within the groove exerts a force against the transition arc surface, while the structure abutting the transition arc surface exerts a force against the groove, thus forming an assembly. Furthermore, if the transmission force is too great, the shaft will slip, achieving mechanical overload protection and self-protection. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 This is a structural diagram of the shaft body of the transmission shaft processing technology of the present invention;

[0038] Figure 2 This is a schematic structural diagram of a fixed shaft in the processing technology for the transmission shaft according to the present invention;

[0039] Figure 3 A cross-sectional view of the shaft body of the transmission shaft processing technology of the present invention;

[0040] Figure 4 A cross-sectional view of a fixed shaft in the processing technology for the transmission shaft according to the present invention;

[0041] Figure 5 This is a schematic structural diagram of the cooperation between the first connecting portion and the internal thread of the processing technology for the transmission shaft according to the present invention;

[0042] Figure 6 This is a structural schematic diagram of the cooperation between the second connecting portion and the external thread in the processing technology of the transmission shaft described in the present invention.

[0043] Description of reference numerals:

[0044] 10. Shaft body; 101. Transmission groove; 102. External thread; 103. Circular shaft segment; 104. Parabolic groove; 105. Transition arc surface; 106. Internal thread; 107. Arc surface;

[0045] 20. Fixed shaft; 201. First connecting portion; 202. Locking portion;

[0046] 2021. Socket connection portion; 2022. Second connection portion. DETAILED DESCRIPTION

[0047] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0048] In addition, it should be noted that the terms "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside", etc. are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element of the present invention must have a specific orientation. Therefore, it cannot be understood as a limitation on the present invention.

[0049] When an element is referred to as being “fixed to,” “disposed on,” or “provided on” another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being “connected to” another element, it can be directly connected to the other element or indirectly connected to the other element.

[0050] Unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be interpreted broadly. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediary; and internal communication between two components or interaction between two components. Those skilled in the art will understand the specific meanings of these terms in the present invention based on specific circumstances.

[0051] Example

[0052] Please refer to Figure 1 、 Figure 2 、 Figure 3 、 Figure 4 、 Figure 5 and Figure 6 As shown, this embodiment provides a processing technology for a transmission shaft, which includes a shaft body 10 and a fixed shaft 20; hereinafter, the processing accuracy level of the shaft body 10 and the fixed shaft 20 is at least IT8, and the accuracy level of surface processing should not be lower than IT8.

[0053] The processing technology of the shaft body 10 includes the following steps:

[0054] In this step, one end portion of the shaft body 10 blank is processed to form a cylindrical clamping section for centering clamping.

[0055] The cylindrical clamping section can be clamped in a centered manner to ensure machining accuracy during processing. For example, a four-jaw chuck can be used for centered clamping.

[0056] In this step, after centering and clamping, the shaft body 10 blank is turned to form a rough workpiece of three stepped shafts with decreasing or increasing steps.

[0057] The rough workpiece with machining allowance is cut by milling or general turning to improve the efficiency of subsequent processing.

[0058] like Figure 1 and Figure 3 As shown, in this step, a transmission groove 101 is cut on the middle part of the intermediate step shaft. The processing steps of the transmission groove 101 of the intermediate step shaft include: cutting out the transmission groove 101 and reserving the shaft shoulders on both sides; and performing transition chamfering between the transmission groove 101 and the shaft shoulders by using an external circular cutter.

[0059] Specifically, the intermediate stepped shaft where the transmission groove 101 is located can be used to install a transmission wheel, such as a sprocket or pulley. The design of the groove structure can form a groove to accommodate a silicone ring for positioning and assembly. Key grooves can be designed at the shaft shoulders on both sides to install the sprocket to achieve the purpose of assembly.

[0060] Furthermore, in this step, the processing steps of the transmission groove 101 are as follows: retaining the machining allowance to cut the rough blank annular groove; using an R2 ball end cutter to symmetrically machine the side walls and bottom corner arc transition surface of the rough blank annular groove. The R2 ball end cutter can prevent machining interference, so as to ensure smooth machining and machining accuracy, and the symmetrical side walls form a 40° angle; thus, the trapezoidal structure of the transmission groove 101 is completed. This forms a trapezoidal groove. The trapezoidal groove structural design can increase the contact area, provide inward support force, and improve the stability of the assembly.

[0061] like Figure 1 and Figure 3 As shown, in this step, the external thread 102 is turned or tapped on the minimum step shaft; the processing steps of the external thread 102 of the minimum step shaft include: cutting a cutting groove on the connection position of the minimum step shaft and the shaft shoulder by a cutting tool; and processing the external thread 102 by a turning tool or a thread turning tool.

[0062] Specifically, the shear groove design allows for smooth shearing during thread processing, ensuring thread integrity and enabling smooth thread engagement. The end of the smallest step shaft can be chamfered to facilitate docking assembly. The thread can be a fine-pitch thread structure, or, if desired, a trapezoidal or rectangular thread to increase torque.

[0063] like Figure 1 and Figure 3 As shown, in this step, a circular shaft segment 103, a parabolic groove 104 and a transition arc surface 105 are processed in sequence starting from the shaft end on the maximum step shaft. The curvature of the parabolic groove 104 from the circular shaft segment 103 to the vertex of the parabola is greater than the curvature from the vertex of the parabola to the transition arc surface 105. The transition arc surface 105 is located at the notch of the parabolic groove 104 and extends to the middle step shaft and is bent outward.

[0064] Specifically, the parabolic groove 104 uses the highest point as the dividing line, and the curvature of the arc surface close to the transition arc surface 105 is designed to be relatively small. The structure that is locked and rotated in the parabolic groove 104 will have a force or component force toward the transition arc surface 105. The structure that cooperates with the raised transition arc surface 105 can provide a force or component force toward the direction of the parabolic groove 104. The parabolic groove 104 and the transition arc surface 105 are matched and connected and transmitted. If the transmission force is too large, the overload protection will be triggered, and the parabolic groove 104 and the transition arc surface 105 will be idle, forming corresponding protection. The modified transmission method can be applied to low-speed vehicles, such as the drive shaft on the drive shaft of the elderly power-assisted bicycle.

[0065] Furthermore, the processing equation of the parabolic curve of the parabolic groove 104 in this step is:

[0066] X 2 =2pY, or, Y 2 =2pX;

[0067] Wherein, p is the focal coordinate value, 0<p, and X represents the X-axis value, and Y represents the Y-axis value; when 2pY or 2pX takes a positive value, the opening of the parabola is toward the positive direction of the coordinate axis; when 2pY or 2pX takes a negative value, the opening of the parabola is toward the negative direction of the coordinate axis; the parabolic groove 104 is machined according to the machining equation.

[0068] According to the above processing equation, the parabolic curve can be accurately calculated and converted into the code of the equipment, and then the parabolic groove 104 can be processed by a CNC lathe to obtain a precise parabolic groove 104 structure and improve practicality.

[0069] Furthermore, the maximum step shaft processing steps of the shaft body 10 are: rough machining with a 35° outer circular diamond cutter, and then multiple finishing with an R2 ball end cutter; the spindle speed for rough machining is 800 rpm, and the feed speed is 150 mm / min; the spindle speed for finishing is 1500 rpm, and the feed speed is 100 mm / min.

[0070] Specifically, through multiple roughing and finishing operations, the roughness of the machined surface can be improved. Furthermore, at high rotational speeds and relatively low feed rates, surface accuracy and roughness can be improved. Furthermore, the use of an R2 ball-end cutter allows for precise machining of the workpiece surface, ensuring the accuracy of the resulting curved surface.

[0071] Furthermore, if Figure 1 and Figure 3As shown, in this step, a blind hole is drilled on the end face where the largest stepped shaft is located, and an internal thread 106 is machined. The blind hole is also provided with a curved surface 107, which is located between the internal thread 106 and the end of the blind hole. After the blind hole is drilled to a certain depth, the curved surface 107 is machined along the end toward the inner diameter, gradually reducing. A thread groove is machined on the bottom surface of the blind hole, and then an internal thread 106 is machined to the same depth as the thread groove.

[0072] Specifically, a twist drill is used to make a hole, and then an arc surface 107 section and an internal thread 106 section are processed. The design of the arc surface 107 facilitates the insertion of the connecting end of the fixed shaft 20. At the same time, the fit between the arc surfaces can be evenly stressed, and stress concentration is not likely to occur, or damage to the fit is caused, thereby improving the stability of the structural fit.

[0073] In this embodiment, the processing technology for the fixed shaft 20 includes the following steps:

[0074] like Figure 2 and Figure 4 As shown, in this step, the fixed shaft 20 blank is cut to form a first connecting portion 201 that is threadedly engaged with the internal thread 106 of the blind hole of the shaft body 10, and a locking portion 202 with a curved surface 107 is cut on the fixed shaft 20 blank located at the other end of the first connecting portion 201.

[0075] In this way, the fixed shaft 20 can be machined by clamping the clamping section of the shaft body 10. Simultaneously, during the machining process, the fixed shaft 20 and the shaft body 10 can be assembled to determine the assembly accuracy between the structures, achieving a preliminary inspection effect. Furthermore, assembly-based machining ensures consistent machining accuracy across the entire product, for example, ensuring that the maximum diameter of the lock head 202 is the same as the maximum diameter of the shaft body 10, or that the surface roughness is the same, resulting in consistent quality.

[0076] In this step, a blind hole is drilled on the end surface of the lock portion 202 , and a sleeve portion 2021 for engaging with the side wall of the transmission groove 101 and a second connecting portion 2022 for threaded engagement with the external thread 102 are cut along the blind hole from outside to inside.

[0077] Specifically, the first connecting portion 201 is a blind hole provided in the end head and is processed to cooperate with the external thread 102 of the shaft body 10. Figure 5 and Figure 6As shown, the first connecting portion 201 is connected to the internal thread 106 of the shaft body 10, that is, it is assembled on the end face of the largest stepped shaft of the shaft body 10; the second connecting portion 2022 is connected to the external thread 102 of the shaft body 10, that is, it is assembled on the end face of the smallest stepped shaft of the shaft body 10, thus achieving the purpose of assembling at both ends. In this way, the shaft body 10 can be locked and connected by multiple fixed shafts 20, or two shaft bodies 10 can be connected by a single fixed shaft 20 (multiple shaft bodies 10 can be connected as needed), thereby improving the flexibility of use.

[0078] Finally, in this step, the shaft body 10 and the clamping section of the fixed shaft 20 are removed, cut, and polished to complete the processing.

[0079] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present invention should be included in the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A process for processing a transmission shaft, characterized in that: The transmission shaft includes a shaft body and a fixed shaft; The processing technology of the shaft body includes the following steps: One end of the shaft blank is processed to form a cylindrical clamping section for centering clamping; After centering and clamping, the shaft blank is turned to form a rough workpiece of three stepped shafts with decreasing or increasing steps; A transmission groove is cut in the middle of the intermediate stepped shaft; Turn or tap the external thread on the smallest step shaft; A circular shaft segment, a parabolic groove, and a transition arc surface are sequentially machined on the maximum step shaft starting from the shaft end. The curvature of the parabolic groove from the circular shaft segment to the vertex of the parabola is greater than the curvature from the vertex of the parabola to the transition arc surface. The transition arc surface is located at the notch of the parabolic groove and extends to the middle step shaft and is curved outward. Drill a blind hole on the end face where the largest stepped shaft is located and machine the internal thread; The processing technology of the fixed shaft includes the following steps: The fixed shaft blank is cut to form a first connecting portion that is threadedly engaged with the internal thread of the blind hole of the shaft body. After the first connecting portion is assembled and connected with the blind hole internal thread of the shaft body, a locking portion with an arc-shaped surface is cut and processed on the fixed shaft blank located at the other end of the first connecting portion; Drilling a blind hole on the end surface of the lock portion, and cutting and processing from the outside to the inside along the blind hole to form a sleeve portion for engaging with the side wall of the transmission groove and a second connecting portion for threaded engagement with the external thread; The shaft body and the fixed shaft clamping section are removed, cut, and then polished to complete the processing.

2. The process for processing a transmission shaft according to claim 1, characterized in that: The processing equation of the parabolic curve of the parabolic groove is: ,or, ; Wherein, p is the focal coordinate value, 0<p, and X represents the X-axis value, and Y represents the Y-axis value; When 2pY or 2pX takes a positive value, the opening of the parabola is in the positive direction toward the coordinate axis; When 2pY or 2pX takes a negative value, the opening of the parabola is toward the negative direction of the coordinate axis; The parabolic groove is machined according to the machining equation.

3. The process for processing a transmission shaft according to claim 1, characterized in that: The transmission groove processing steps of the intermediate stepped shaft include: Cut out the transmission groove and reserve the shaft shoulders on both sides; A transition chamfering process is performed between the transmission groove and the shaft shoulder by using an external circular cutter.

4. The process for processing a transmission shaft according to claim 3, characterized in that: The external thread processing steps of the minimum step shaft include: Cutting a cutting groove at the connection position between the minimum step shaft and the shaft shoulder by a cutting knife; The external thread is machined by a turning tool.

5. The process for processing a transmission shaft according to claim 1, characterized in that: The blind hole is further provided with an arcuate surface, wherein the arcuate surface is located between the internal thread and the end of the blind hole; After the blind hole is drilled to a depth, a curved surface is formed by gradually reducing the diameter of the blind hole toward the inner diameter along the port. A thread groove is machined on the bottom surface of the blind hole, and then an internal thread with the same depth as the thread groove is machined.

6. The process for processing a transmission shaft according to claim 1, characterized in that: The processing steps of the lock head: After the first connecting portion is processed and threadedly engaged with the shaft body; The lock head portion is then processed to ensure that the maximum diameter of the lock head portion is the same as the maximum diameter of the shaft body.

7. The process for processing a transmission shaft according to claim 1, characterized in that: The maximum step shaft processing steps of the shaft body are as follows: Use 35° external circular diamond cutter for rough machining, and then use R2 ball end cutter for multiple finishing operations; The spindle speed of the rough machining is 800 rpm and the feed speed is 150 mm / min; The spindle speed of the finishing process is 1500 rpm and the feed speed is 100 mm / min.

8. The process for processing a transmission shaft according to claim 1, characterized in that: The processing steps of the transmission groove are as follows: Retain the machining allowance to cut out the rough blank annular groove; Use R2 ball end cutter to symmetrically machine the side wall and bottom corner arc transition surface of the rough blank annular groove, and the symmetrical two side walls form an angle of 40°; Complete the processing of the trapezoidal structure of the transmission groove.

9. The process for processing a transmission shaft according to claim 1, characterized in that: The machining accuracy level of the shaft body and the fixed shaft is at least IT8.

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