Machining process of transmission shaft

Abstract

The invention relates to the field of metal processing which is not included in other categories, and provides a processing technology of a transmission shaft which comprises a shaft body and a fixed shaft. The transmission shaft is composed of a shaft body and a fixed shaft, and the transmission shaft can be in butt joint and locked with the internal threads through the first connecting part, or the transmission shaft can be in butt joint and locked with the external threads through the second connecting part. In this way, the shaft body can be locked through the two fixing shafts, or a plurality of shaft bodies are connected in a butt joint mode for use, and high use flexibility is achieved. The shaft body is provided with a parabola groove and a transition cambered surface, and the shaft body can be connected with a power output shaft or a butt joint shaft in a sleeved mode through the parabola groove and the transition cambered surface. Due to the design that the parabola grooves are different in curvature, the structures clamped in the parabola grooves have abutting force towards the transition arc faces, the structures of the transition arc faces have abutting force towards the parabola grooves, and therefore after assembly is formed, if transmission force is too large, slipping can be conducted, and the purpose of overload prevention is achieved.

Description

Technical Field

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

[0002] The transmission shaft is a high-speed, less-supported rotating body, so its dynamic balance is crucial. Generally, the transmission shaft must undergo a dynamic balance test before leaving the factory and be adjusted on a balancing machine. For front-engine, rear-wheel-drive vehicles, it is the shaft that transmits the rotation of the transmission to the main reducer. It can have several sections, and the sections can be connected by universal joints.

[0003] Damage, wear, deformation and loss of dynamic balance of the transmission shaft parts will cause abnormal noise and vibration during driving, and in serious cases will cause damage to related parts. When the car is driving, it will make a "Gedden" sound when starting or accelerating suddenly, and it will obviously feel loose. If it is not the drive gear of the drive axle that is loose, then it is obviously the transmission shaft part that is loose.

[0004] Therefore, the design of the transmission shaft requires a higher matching accuracy to solve the problem of smooth power transmission of the transmission shaft. If the transmission shaft is overloaded, it will cause the transmission shaft to wear and break, which poses a safety problem. 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 purpose, the present invention adopts the following technical scheme: a processing technology for a transmission shaft, the transmission shaft includes a shaft body and a fixed shaft;

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

[0008] Processing one end of the shaft blank 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 steps of decreasing or increasing step shafts;

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

[0011] Turn or tap the smallest step shaft to produce external threads;

[0012] A circular shaft section, a parabolic groove and a transition arc surface are sequentially processed from the shaft end of the largest step shaft, the curvature of the parabolic groove from the circular shaft section to the vertex of the parabola is greater than the curvature from the vertex of the parabola to the transition arc surface, and the transition arc surface extends from the notch of the arc surface groove to the middle step shaft and is bent outward;

[0013] Drill a blind hole on the end face where the largest step 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 connection portion which is threadedly engaged with the internal thread of the blind hole of the shaft body.

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

[0017] Drilling a blind hole on the end surface of the lock head, and cutting and processing from outside to inside along the blind hole to form a sleeve connection portion with the side wall of the transmission groove and a second connection portion threadedly engaged with the external thread;

[0018] The shaft body and the fixed shaft clamping section are removed, cut, and 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; transition chamfering 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 processed by a turning tool or a thread turning tool.

[0027] Furthermore, the blind hole is also provided with an arcuate surface, which is located between the internal thread and the port of the blind hole; after completing the drilling depth processing of the blind hole, the arcuate surface is processed along the port to gradually reduce the inner diameter; a thread groove is processed on the bottom surface of the blind hole, and then an internal thread with the same depth as the thread groove is processed.

[0028] Furthermore, the processing steps of the lock head portion are: first complete the processing of the first connecting portion and thread-lock it with the shaft body; then process the lock head portion to ensure that the maximum diameter of the lock head portion is the same as the maximum diameter of the shaft body.

[0029] Furthermore, the maximum step shaft processing process steps of the shaft body are:

[0030] A 35° outer circular diamond cutter is used for rough machining, and then an R2 ball-end cutter is used for multiple fine machining; the spindle speed for the rough machining is 800 rpm and the feed speed is 150 mm / min; the spindle speed for the fine machining is 1500 rpm and the feed speed is 100 mm / min.

[0031] Furthermore, the processing steps of the transmission groove are:

[0032] The rough blank annular groove is cut by retaining the machining allowance; the side wall and the bottom corner arc transition surface of the rough blank annular groove are symmetrically machined using an R2 ball end cutter, and the symmetrical two side walls form an angle of 40°; the machining of the trapezoidal structure of the transmission groove is completed.

[0033] Furthermore, the machining accuracy level of the shaft body and the fixed shaft is at least IT8.

[0034] After adopting the above technical solution, the present invention has the following advantages compared with the background technology:

[0035] 1. The transmission shaft consists of a shaft body and a fixed shaft. The first connection part can be butt-jointed and locked with the internal thread, or the second connection part can be butt-jointed and locked with the external thread. In this way, both ends of the shaft body and the fixed shaft can be butt-jointed, two fixed shafts can lock the shaft body, or multiple shaft bodies can be butt-jointed for use, which has high flexibility of use.

[0036] 2. The shaft body is provided with a parabolic groove and a transition arc surface, through which the power output shaft or the docking shaft can be sleeved. The different curvatures of the parabolic grooves make the structure engaged in the parabolic groove have a top force toward the transition arc surface, and the structure against the transition arc surface has a top force toward the parabolic groove, thus forming an assembly. At the same time, if the transmission force is too large, it will slip, achieving the purpose of mechanical overload protection and forming self-protection. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 It is a structural schematic diagram of the shaft body of the processing technology of the transmission shaft according to the present invention;

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

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

[0042] Figure 6 It is a structural schematic diagram of the cooperation between the second connecting part 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 section; 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 solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with 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 used 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 drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element of the present invention must have a specific orientation, and therefore cannot be understood as a limitation on the present invention.

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

[0050] Unless otherwise clearly specified and limited, the terms "installed", "connected" and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the invention can be understood according to 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, the transmission shaft 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 of the axle body 10 blank is processed to form a cylindrical clamping section for centering clamping.

[0055] The processed cylindrical clamping section can be clamped in a centering manner to ensure the processing accuracy during processing. For example, the centering clamping can be performed by a four-jaw chuck.

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

[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 and processed 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 shoulder by 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 a pulley. The groove structure can be designed to form a groove for accommodating a silicone ring for positioning and assembly, and key grooves can be designed at the shoulder positions on both sides to install the sprocket to achieve the purpose of assembly.

[0060] Furthermore, the processing steps of the transmission groove 101 in this step are: retaining the processing allowance to cut and process the rough blank annular groove; using the R2 ball end cutter to symmetrically process the side wall and the bottom corner arc transition surface of the rough blank annular groove, and the processing of the R2 ball end cutter can prevent the occurrence of processing interference, so as to smoothly process and ensure the processing accuracy, and the symmetrical two side walls are at an angle of 40°; completing the processing of the trapezoidal structure of the transmission groove 101. In this way, a trapezoidal groove is formed, and the structural design of the trapezoidal groove can increase the contact area, and at the same time can provide inward support force to improve the stability of 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 between the minimum step shaft and the shaft shoulder by a cutting tool; processing the external thread 102 by a turning tool or a thread turning tool.

[0062] Specifically, the design of the cutting groove enables smooth cutting when processing the thread groove to ensure the integrity of the thread processing, and then the thread meshing can be smoothly matched. The end of the smallest step shaft can be designed with a chamfer to facilitate docking assembly. The thread can be a fine pitch thread structure, or it can be designed as a trapezoidal thread or a rectangular thread as needed to increase the 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 sequentially processed starting from the shaft end on the largest 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 extends from the notch of the arc surface groove to the middle step shaft and is bent toward the outside.

[0064] Specifically, the parabolic groove 104 uses the highest point as the dividing line, and the curvature of the arc surface on the side close to the transition arc surface 105 is designed to be relatively small, so that 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 processed according to the processing 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 process steps of the shaft body 10 are: rough machining with a 35° outer circular diamond cutter, and then multiple fine machining with an R2 ball end cutter; the spindle speed for rough machining is 800rpm, and the feed speed is 150mm / min; the spindle speed for fine machining is 1500rpm, and the feed speed is 100mm / min.

[0070] Specifically, after multiple roughing and finishing operations, the roughness of the machined surface can be improved. Moreover, at high speed and relatively low feed rate, the surface accuracy and roughness can be improved. At the same time, the selection of R2 ball end cutter can fit the workpiece surface for processing to ensure the accuracy of the machined 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 step shaft is located, and an internal thread 106 is processed. The blind hole is also provided with an arc surface 107, and the arc surface 107 is located between the internal thread 106 and the port of the blind hole; after the blind hole is drilled to a depth, the arc surface 107 is processed to gradually reduce the inner diameter along the port; a thread groove is processed on the bottom surface of the blind hole, and then an internal thread 106 with the same depth as the thread groove is processed.

[0072] Specifically, a twist drill is used to drill a hole, and then an arc surface 107 section and an internal thread 106 section are processed. The design of the arc surface 107 is convenient for inserting the connecting end of the fixed shaft 20. At the same time, the fit between the arc surfaces can be evenly stressed, and it is not easy to cause stress concentration or damage to the fit, 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 connection 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 from the fixed shaft 20 blank located at the other end of the first connection portion 201.

[0075] In this way, the fixed shaft 20 can be processed by clamping the clamping section of the shaft body 10. At the same time, during the processing, the assembly accuracy between the structures can be judged by assembling the fixed shaft 20 and the shaft body 10, and a preliminary inspection effect can be achieved. At the same time, assembly processing can ensure the same processing accuracy of the 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 the surface roughness is the same, and has the same quality effect.

[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 and processed in sequence along the blind hole from outside to inside.

[0077] Specifically, the first connection portion 201 is a blind hole disposed 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 connection part 201 is matched with the internal thread 106 of the shaft body 10, that is, it is assembled on the end face of the largest step shaft of the shaft body 10; the second connection part 2022 is matched with the external thread 102 of the shaft body 10, that is, it is assembled on the end face of the smallest step shaft of the shaft body 10; the purpose of assembling at both ends is achieved. In this way, the shaft body 10 can be locked and connected through multiple fixed shafts 20, or two shaft bodies 10 can be connected through one fixed shaft 20 (multiple shaft bodies 10 can be connected according to needs), 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 is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope 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 comprises the following steps: Processing one end of the shaft blank 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 steps of decreasing or increasing step shafts; A transmission groove is cut and processed in the middle of the intermediate stepped shaft; Turn or tap the smallest step shaft to produce external threads; A circular shaft section, a parabolic groove and a transition arc surface are sequentially processed from the shaft end of the largest step shaft, the curvature of the parabolic groove from the circular shaft section to the vertex of the parabola is greater than the curvature from the vertex of the parabola to the transition arc surface, and the transition arc surface extends from the notch of the arc surface groove to the middle step shaft and is bent outward; Drill a blind hole on the end face where the largest step 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 connection portion which is threadedly engaged with the internal thread of the blind hole of the shaft body. After the first connection part is assembled and connected with the blind hole internal thread of the shaft body, a locking part with an arc surface is cut and processed on the fixed shaft blank located at the other end of the first connection part; Drilling a blind hole on the end surface of the lock head, and cutting and processing from outside to inside along the blind hole to form a sleeve connection portion with the side wall of the transmission groove and a second connection portion threadedly engaged with the external thread; The shaft body and the fixed shaft clamping section are removed, cut, and polished to complete the processing.

2. The processing technology for the transmission shaft according to claim 1, characterized in that: The processing equation of the parabolic curve of the parabolic groove is: X 2 =2pY, or, Y 2 =2pX; 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 processing technology for the 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; The transmission groove and the shaft shoulder are processed by transition chamfering with an external circular cutter.

4. The processing technology for the transmission shaft according to claim 3 is 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 processed by a turning tool or a thread turning tool.

5. The processing technology for the transmission shaft according to claim 1, characterized in that: The blind hole is further provided with an arc surface, and the arc 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 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 processing technology for the transmission shaft according to claim 1, characterized in that: The processing steps of the lock head are as follows: Firstly, the first connection part is processed and thread-locked with the shaft body; The lock head is then processed to ensure that the maximum diameter of the lock head is the same as the maximum diameter of the shaft body.

7. The processing technology for the transmission shaft according to claim 1, characterized in that: The maximum step shaft processing process steps of the shaft body: Use a 35° external diamond cutter for rough machining, and then use an 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 process 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 processing technology for the 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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