D-shaped hole micro gear machining method and tool

Abstract

The invention provides a D-shaped hole micro gear machining method and tool. The method comprises the steps that firstly, a shaft gear blank is machined according to a shaft gear machining technology, secondly, a gear part is manufactured through a gear hobbing technology, then, a prefabricated hole is manufactured through an electric pulse machining center, then, a D-shaped hole is manufactured through slow wire feeding, and finally, a plurality of D-shaped hole micro gear single pieces are manufactured through slow wire feeding slitting; the tool is composed of a clamping block and a jackscrew. A block body through hole for concentrically clamping a shaft gear blank is formed in the center of a block body of the square clamping block, locking screw holes are further symmetrically formed in the square clamping block, and jackscrews are screwed in the locking screw holes to lock the position of the long optical axis section. The technical problems that in the prior art, a D-shaped hole micro gear is inconvenient to machine and low in efficiency are solved. And the method is good in manufacturability, convenient to operate, high in processing efficiency and suitable for popularization.

Description

Technical Field

[0001] The present invention belongs to the technical field of manufacturing of working and transporting gears, and particularly relates to a processing method and tooling for a D-shaped hole micro gear. Background Art

[0002] With the development and progress of society, due to space and structural limitations, especially small gears with D-shaped holes have been widely used in many industrial fields such as precision instruments, watches, and small planetary speed reducers. Among them, the sun gear in the planetary speed reducer is a typical representative of this small gear part. The D-shaped hole of the sun gear is fitted and connected with the motor shaft (D-shaped shaft) to achieve rotational motion to realize the high-speed rotation of the motor, and finally achieve low-speed output through planetary reduction.

[0003] Taking the commonly used sun gear of the planetary speed reducer shown in Figures 1(a) and 1(b) as an example, the modulus m of this sun gear product is 0.25, the number of teeth z is 20, the inner hole is D-shaped, and the thickness L0 is 1.5 +0.1 mm. Since the D-shaped hole of this part is too small, it cannot be processed with a mandrel according to the processing method of the piece gear. In this regard, the following technical solutions are proposed. Summary of the Invention

[0004] The technical problem solved by the present invention: Provide a processing method and tooling for a D-shaped hole micro gear, and adopt the technological steps of manufacturing a shaft gear blank, manufacturing teeth, manufacturing a prefabricated hole, manufacturing a D-shaped hole, and slicing to solve the technical problems of inconvenient processing and low efficiency of the D-shaped hole micro gear in the prior art.

[0005] The technical solution adopted by the present invention: A processing method for a D-shaped hole micro gear, first manufacturing a shaft gear blank according to the shaft gear processing technology, secondly manufacturing the tooth part by using the hobbing processing technology, then manufacturing a prefabricated hole by using an electric pulse machining center, then manufacturing a D-shaped hole by slow wire cutting, and finally obtaining multiple single pieces of D-shaped hole micro gears by slow wire cutting and slicing.

[0006] In the above technical solution, further: it includes the following steps: S1. Manufacturing a shaft gear blank: The obtained shaft gear blank is composed of a short optical shaft section, an intermediate optical shaft section, and a long optical shaft section that are integrally formed coaxially. Among them, the diameters of the long and short optical shaft sections are equal and smaller than the diameter of the intermediate optical shaft section; the diameter of the intermediate optical shaft section matches the diameter of the D-shaped hole micro gear; the axial length of the intermediate optical shaft section matches the thickness of multiple D-shaped hole micro gears; the axial length of the short optical shaft section is less than the axial length of the intermediate optical shaft section; the length of the long optical shaft section is greater than the axial length of the intermediate optical shaft section.

[0007] S2. Manufacturing teeth: Using the hobbing processing technology to process the intermediate optical shaft section to obtain the tooth part of the D-shaped hole micro gear.

[0008] S3. Cutting short: Cutting short the short optical shaft section and making the axial length of the cut short short optical shaft section ≤ 2 mm.

[0009] S4. Preparing pre - drilled holes: Use an electric pulse machining center to prepare axially - penetrating pre - drilled holes, and make the center of the pre - drilled holes non - concentric with the center of the shaft gear blank.

[0010] S5. Preparing D - shaped holes: Clamp the D - shaped hole micro - gear machining tooling with a vise and press - fit it onto the flat plate of the slow - wire cutting machine. Use the D - shaped hole micro - gear machining tooling to clamp the long optical axis section. After threading the wire, use slow - wire electrical discharge wire cutting to prepare the D - shaped holes.

[0011] S6. Slitting: Rotate the D - shaped hole micro - gear machining tooling clamped by the vise and the shaft gear blank clamped by the D - shaped hole micro - gear machining tooling together by 90°. After using slow - wire electrical discharge wire cutting to remove the short optical axis section, use slow - wire electrical discharge slitting to obtain multiple single - piece D - shaped hole micro - gears.

[0012] In the above - mentioned technical solution, further: The module m of the D - shaped hole micro - gear is m ≤ 0.3 mm, the number of teeth Z ≤ 20, the inner hole diameter ≤ 3 mm and is a D - shaped hole, and the gear width L0(1.5 + 0.1) ≤ 2 mm.

[0013] In the above - mentioned technical solution, further: The short optical axis section and the long optical axis section are the clamping and positioning references during tooth manufacturing in step S2, pre - drilled hole preparation in step S4, D - shaped hole preparation in step S5, and slitting in step S6; The outer - circle tolerance grade accuracy requirements of the short optical axis section and the long optical axis section are not lower than h7.

[0014] In the above - mentioned technical solution, further: The accuracy requirement of the tooth part is not lower than grade 6.

[0015] In the above - mentioned technical solution, preferably: The diameter of the pre - drilled hole is φ0.3 - 0.5 mm; The eccentricity between the center of the pre - drilled hole and the center of the shaft gear blank is 0.5 mm.

[0016] The present invention also claims protection for a D - shaped hole micro - gear machining tooling. The D - shaped hole micro - gear machining tooling uses any method to machine D - shaped hole micro - gears. The D - shaped hole micro - gear machining tooling consists of a clamping block and a set screw; The clamping - block body is a square structure, and a through - hole is made in its center. The through - hole in the block concentrically locates and clamps the long optical axis section of the shaft gear blank; Taking the center of the through - hole in the block as the axis of symmetry, the clamping - block body is provided with axially - symmetric locking screw holes; The center line of the locking screw holes is perpendicular to the center line of the through - hole in the block; The locking screw holes are fitted with set screws in a rotating manner, and the set screws are used to lock the position of the long optical axis section; The inner - side shaft end face of the long optical axis section closely fits the clamping - block body.

[0017] In the above - mentioned technical solution, further: The tooling is quenched to improve its hardness.

[0018] Advantages of the present invention compared with the prior art: 1. The present invention has good processability, convenient operation, high processing efficiency, and is suitable for popularization.

[0019] 2. Based on the traditional method of processing only one part at a time, the present invention can process five finished products, improving efficiency and saving costs. The minimum hole diameter size that can be processed by the traditional method is 2 mm, while the minimum hole diameter size that can be processed by the method of the present invention is 1 mm. It increases the processing stability of D-shaped hole micro-gears and is applicable to the processing of micro-gears and small gears in watches, with relatively wide applications.

[0020] 3. The present invention prepares blanks through processes such as forging to ensure that the gear shaft has high strength and stiffness, providing a solid foundation for subsequent processing. Hobbing is a continuous process without idle strokes, with high production efficiency and is easy to ensure that the processed gears have relatively accurate pitch, suitable for processing gears with small cumulative error adjustment requirements. The electric pulse machine tool has a machining accuracy of the μm level and is suitable for processing high-precision small workpieces. The surface finish can reach 0.1 Ra, meeting the high requirements for surface quality of micro-gears. The wire-cut EDM has a high machining accuracy level, generally able to reach the 0.001 mm level or even higher, ensuring the accuracy of products. During the slitting process, the wire-cut EDM can maintain high precision to ensure that each micro-gear meets the design requirements. The connection between each process is tight and the process is smooth, improving production efficiency.

[0021] 4. The short optical axis section and long optical axis section of the present invention are used as clamping and positioning bases, which can accurately clamp, position and control machining accuracy, helping to reduce the scrap rate, improve product quality and production efficiency. Using unified positioning reference and tolerance grade requirements, the quality is stable and consistent, improving the consistency and reliability of products.

[0022] 5. The electric pulse machining center of the present invention has high-precision machining capabilities, which can ensure that the aperture diameter, hole depth and position accuracy of the prefabricated holes meet the design requirements. This high-precision machining helps to reduce the error accumulation in subsequent machining processes and improve the overall machining accuracy. Through the electric pulse machining center, the position of the prefabricated holes can be flexibly adjusted to be non-concentric with the center of the shaft gear blank. This flexibility helps to meet specific design requirements. Setting the prefabricated holes to be non-concentric with the center of the shaft gear blank can, to a certain extent, reduce the stress concentration phenomenon, which helps to extend the service life of the gears and reduce failures such as cracks and fractures caused by stress concentration.

[0023] 6. The tooling of the present invention has a simple structure, convenient clamping, and precise and stable cooperation. The tooling is subjected to quenching treatment to increase its hardness, will not cause wear, can be reused, improving the economy of the tooling and reducing production costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] FIG. 1(a) is a sectional view process drawing of a common sun gear of a planetary reducer; FIG. 1(b) is a front view process drawing of a common sun gear of a planetary reducer; Figure 2This is the front view of the blank of the shaft gear of the present invention; Figure 3 This is the front view of the blank of the shaft gear after gear cutting in Step 2 of the present invention; Figure 4(a) is the front view sectional view of the blank of the shaft gear after shortening in Step 3 of the present invention; Figure 4(b) is the side view of the blank of the shaft gear after shortening in Step 3 of the present invention; Figure 5(a) is the front view sectional view of the blank of the shaft gear after pre - drilled hole making in Step 4 of the present invention; Figure 5(b) is the side view of the blank of the shaft gear after pre - drilled hole making in Step 4 of the present invention; Figure 6(a) is the front view of the clamping block of the D - shaped hole micro - gear processing tooling of the present invention; Figure 6(b) is the sectional view of the clamping block of the D - shaped hole micro - gear processing tooling; Figure 7(a) is the sectional view of the tooling clamping the blank of the shaft gear of the present invention; Figure 7(b) is the schematic view in the A - direction of Figure 7(a) of the present invention; Figure 8(a) is the front view sectional view of the blank of the shaft gear after D - shaped hole making in Step 5 of the present invention; Figure 8(b) is the side view of the blank of the shaft gear after D - shaped hole making in Step 5 of the present invention; Figure 9(a) is the front view sectional view of the tooling clamping the blank of the shaft gear after cutting off the short optical shaft section in Step 6 of the present invention; Figure 9(b) is the left view of Figure 9(a) of the present invention; Figure 10 This is the overview of the process flow chart of the present invention; In the figure: 1 - blank of the shaft gear, 101 - short optical shaft section, 102 - intermediate optical shaft section, 103 - long optical shaft section, 2 - tooth part, 3 - pre - drilled hole, 4 - D - shaped hole, 5 - D - shaped hole micro - gear, 6 - D - shaped hole micro - gear processing tooling, 601 - clamping block, 6011 - block through - hole, 6012 - locking wire hole, 602 - setscrew. Detailed implementation manners

[0025] Next, in combination with the related drawings 1 - 10 of the embodiments of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0026] It should be noted that: for the D - shaped hole micro - gear 5 to be processed in the present invention, the module m ≤ 0.3 mm, the number of teeth Z ≤ 20, the inner hole diameter ≤ 3 mm and it is a D - shaped hole, and the gear width L0(1.5 + 0.1) ≤ 2 mm.

[0027] The following takes the process requirements for machining the sun gears of common planetary reducers shown in Figures 1(a) and 1(b) as an example for description: A method for machining D-shaped hole micro gears. First, a shaft gear blank 1 is machined according to the shaft gear machining process. Secondly, the tooth part 2 is machined by a hobbing process. Then, a prefabricated hole 3 is machined using an electric pulse machining center. Next, a D-shaped hole 4 is machined by a slow wire cutting process. Finally, multiple single-piece D-shaped hole micro gears 5 are obtained by slow wire cutting and slicing.

[0028] It should be noted that: The blank is prepared through processes such as forging to ensure that the gear shaft has high strength and stiffness, providing a solid foundation for subsequent machining. The hobbing process is a continuous process without idle strokes, with high production efficiency. It is easy to ensure that the machined gear has a relatively accurate pitch and is suitable for machining gears with small cumulative error adjustment requirements. The electric pulse machine tool has a machining accuracy of the μm level and is suitable for machining high-precision small workpieces; the surface finish can reach 0.1 Ra, meeting the high requirements for the surface quality of micro gears. The slow wire cutting process has a high machining accuracy level, generally able to reach the 0.001 mm level or even higher, ensuring the accuracy of the D-shaped hole 4. During the slicing process, the slow wire cutting can maintain high precision to ensure that each micro gear 5 meets the design requirements. The connection between each process is tight and the process is smooth, improving the production efficiency.

[0029] In the above embodiment, further: it includes the following steps (as Figure 10 shown): (as Figure 2 shown) S1. Manufacture the shaft gear blank: The obtained shaft gear blank 1 is composed of a short smooth shaft section 101, an intermediate smooth shaft section 102, and a long smooth shaft section 103 that are coaxially integrally formed. Among them, the diameters of the long and short smooth shaft sections 103 and 101 are equal and smaller than the diameter of the intermediate smooth shaft section 102; the diameter of the intermediate smooth shaft section 102 matches the diameter of the D-shaped hole micro gear 5; the axial length of the intermediate smooth shaft section 102 matches the thickness of multiple D-shaped hole micro gears 5; the axial length of the short smooth shaft section 101 is smaller than the axial length of the intermediate smooth shaft section 102; the length of the long smooth shaft section 103 is greater than the axial length of the intermediate smooth shaft section 102.

[0030] It should be noted that: The short smooth shaft section 101, the intermediate smooth shaft section 102, and the long smooth shaft section 103 are coaxially integrally formed, ensuring the integrity and coaxiality of the shaft gear blank, which is beneficial to the accuracy control of subsequent machining and assembly. The dimensions of each part of the shaft gear blank are standardized, which is beneficial to subsequent machining. The design of the short smooth shaft section 101 and the long smooth shaft section 103 provides convenient positioning and clamping points for subsequent machining and assembly, which is beneficial to ensuring the accuracy of machining and assembly.

[0031] In the above embodiments, further: the short optical axis section 101 and the long optical axis section 103 are the clamping and positioning references during gear cutting in step S2, pre - drilled hole making in step S4, D - shaped hole making in step S5, and slitting in step S6; the outer - circle tolerance grade accuracy requirements of the short optical axis section 101 and the long optical axis section 103 are not lower than h7 (such as Figure 2 shown).

[0032] It should be noted that: taking the short optical axis section 101 and the long optical axis section 103 as the clamping and positioning references can ensure accurate positioning in subsequent processing steps such as gear cutting (S2), pre - drilled hole making (S4), D - shaped hole making (S5), and slitting (S6). This is conducive to reducing processing errors and improving the overall processing accuracy. Since the short optical axis section 101, the middle optical axis section 102, and the long optical axis section 103 are integrally formed coaxially, using the short optical axis section 101 and the long optical axis section 103 as the positioning references can ensure the coaxiality between various parts during the processing, further improving the processing accuracy. Using the standardized short optical axis section 101 and long optical axis section 103 as the positioning references can simplify the clamping process, reduce the clamping time and adjustment time, thereby improving the processing efficiency. Precise clamping positioning and processing accuracy control help reduce the scrap rate, improve product quality and production efficiency. Using unified positioning references and tolerance grade requirements, the quality is stable and consistent, improving the consistency and reliability of the product.

[0033] Specifically: the thickness L0 of the D - shaped hole micro - gear 5 is 1.5 mm, and the middle optical axis section 102 is designed to be 10 mm (5×1.5 mm + wire diameter of 0.25 mm during cutting + discharge amount) to ensure that five D - shaped hole micro - gears 5 are obtained after slitting in step 6; the outer circles of the short optical axis section 101 and the long optical axis section 103 are φ3h7( 0 -0.01 ). The lengths of the short optical axis section 101 and the long optical axis section 103 cannot be designed too long to avoid the tooth part accuracy not meeting the requirements. The length of the short optical axis section 101 is 8 mm, the length of the long optical axis section 103 is 12 mm, and the length of the middle optical axis section 102 is 10 mm.

[0034] (such as Figure 3 shown) S2. Gear cutting: The tooth part 2 of the D - shaped hole micro - gear 5 is processed by hobbing the middle optical axis section 102. In the above embodiments, further: the accuracy requirement of the tooth part 2 is not lower than grade 6.

[0035] It should be noted that: The accuracy requirement of the tooth part 2 is not lower than grade 6, which means that the key dimensions such as the tooth pitch and tooth profile of the gear are precisely controlled. The high-precision tooth part can reduce the vibration and noise during the meshing process of the gear, improving the smoothness of the transmission system. The high-precision tooth part has a high surface finish, reducing the friction and wear during the meshing process of the gear. The tooth part with an accuracy requirement not lower than grade 6 can bear a greater load, improving the load-bearing capacity of the gear. The accuracy requirement of the tooth part 2 not lower than grade 6 can meet the design requirements of many high-precision transmission systems. The hobbing process has the characteristics of high efficiency and continuous cutting, and can quickly machine high-precision tooth parts. This helps to improve production efficiency, reduce manufacturing costs, and meet the large market demand for high-precision micro gears.

[0036] (As shown in Figures 4(a) and 4(b)) S3. Cut short: Cut short the short optical axis section 101 and make the axial length of the cut short short optical axis section 101 ≤ 2 mm. That is, the remaining length L of the short optical axis section 101 00 = 2 mm. The purpose of cutting short is to: shorten the depth of the prefabricated hole made in step S4, reducing the difficulty of manufacturing and processing in subsequent processes; in addition, the remaining length L of the short optical axis section 101 00 = 2 mm also serves to align the center of the micro gear 5 in subsequent step S5 when making the D-shaped hole 4, ensuring that the cut D-shaped hole 4 coincides with the center of the micro gear 5, that is, the so-called coaxiality. That is, cutting short the short optical axis section 101 reduces the depth of the prefabricated hole made in subsequent step S4. A shallower prefabricated hole is easier to machine, reducing problems such as tool wear, extended processing time, and decreased machining accuracy that may be caused by too large a hole depth, helping to improve the overall processing efficiency and shorten the production cycle.

[0037] (As shown in Figures 5(a) and 5(b)) S4. Make the prefabricated hole: Use an electric pulse machining center to make an axially penetrating prefabricated hole 3, and make the center of the prefabricated hole 3 non-concentric with the center of the shaft gear blank 1.

[0038] The electric pulse machining center has high-precision machining capabilities, and can ensure that the hole diameter, hole depth, and hole position accuracy of the prefabricated hole 3 meet the design requirements. This high-precision machining helps to reduce the error accumulation in subsequent machining processes and improve the overall machining accuracy. Through the electric pulse machining center, the position of the prefabricated hole 3 can be flexibly adjusted to be non-concentric with the center of the shaft gear blank 1. This flexibility helps to meet specific design requirements. Setting the prefabricated hole 3 to be non-concentric with the center of the shaft gear blank 1 can, to a certain extent, reduce the stress concentration phenomenon, which helps to extend the service life of the gear and reduce faults such as cracks and fractures caused by stress concentration. Setting the prefabricated hole 3 to be axially penetrating can simplify subsequent machining processes. For example, when machining the D-shaped hole in subsequent steps, it is more convenient to perform positioning and cutting operations.

[0039] In the above embodiments, preferably: the diameter of the prefabricated hole 3 is φ0.3 - 0.5 mm (as shown in Figure 5); the eccentricity between the center of the prefabricated hole 3 and the center of the shaft gear blank 1 is 0.5 mm. The size of the eccentricity distance and the size of the pre-hole are designed according to the size of the D-shaped hole 4 to ensure the convenience and feasibility of the processing process.

[0040] It should be noted that: the diameter range of the prefabricated hole 3 is set to φ0.3 - 0.5 mm. This size range is neither too large nor too small, which can ensure precise cutting operations. At the same time, this size range also helps to reduce the accumulation of errors during the processing and improve the overall processing accuracy. The design with an eccentricity of 0.5 mm causes a certain offset between the center of the prefabricated hole 3 and the center of the shaft gear blank 1. This offset can be used as a positioning reference during the subsequent processing of the D-shaped hole 4, facilitating the accurate determination of the position and shape of the D-shaped hole 4. At the same time, since the prefabricated hole 3 already exists, the cutting resistance can be reduced during the cutting of the D-shaped hole 4, improving the cutting efficiency. The reasonable design of the prefabricated hole 3 and the setting of the eccentricity can enhance the structural stability of the shaft gear blank 1.

[0041] S5. Manufacturing the D-shaped hole: Clamp the D-shaped hole micro gear processing tooling 6 with a vise and press-fit it on the slow wire cutting machine table. Use the D-shaped hole micro gear processing tooling 6 shown in Figures 6(a) and 6(b) to clamp the long optical axis section 103 (shown in Figures 7(a) and 7(b)). After threading, use slow wire electrical discharge wire cutting to manufacture the D-shaped hole 4 (shown in Figures 8(a) and 8(b)). The manufactured D-shaped hole 4 ensures the dimensional requirements of φ2.5 +0.1 mm, 0.5 +0.01 mm.

[0042] It should be noted that: the slow wire electrical discharge wire cutting technology has high-precision machining capabilities, which can ensure that the size of the D-shaped hole 4 meets φ2.5 +0.1 mm, 0.5 +0.01Strict requirements of mm. This high-precision machining helps reduce error accumulation in subsequent processes and improve accuracy. Using the slow wire electrical discharge machining technology to machine the D-shaped hole 4 can ensure the consistency of the machining size and shape of the D-shaped hole 4, thereby improving the overall quality and reliability of the product. The slow wire electrical discharge machining technology can adapt to the machining of various complex shapes. During the machining process, the machining parameters of the slow wire electrical discharge machine tool, such as cutting speed, wire tension, etc., can be adjusted according to actual needs to optimize the machining effect and improve machining efficiency. The slow wire electrical discharge machining technology has high machining capabilities and can complete the machining of the D-shaped hole 4 in a short time. This high efficiency helps shorten the production cycle and improve the overall production efficiency. Although the initial investment in the slow wire electrical discharge machine tool is relatively large, due to its high precision, high efficiency, and wide adaptability, it can significantly reduce the costs in subsequent machining and assembly processes. The slow wire electrical discharge machining technology adopts a non-contact machining method, reducing machining errors caused by mechanical friction and wear. At the same time, this technology also has an automatic detection and compensation function, which can further reduce machining errors and improve product quality. The high-precision machining of the D-shaped hole 4 helps improve the stability and reliability of the transmission system. By ensuring the dimensional and shape accuracy of the D-shaped hole 4, transmission failures and damages caused by assembly errors can be reduced, and the service life of the product can be extended.

[0043] S6. Slitting: Rotate the D-shaped hole micro gear machining fixture 6 clamped by the vise and the shaft gear blank 1 clamped by the D-shaped hole micro gear machining fixture 6 together by 90°. After the short optical axis section 101 is removed by slow wire electrical discharge machining (as shown in Figures 9(a) and 9(b)), multiple single pieces of D-shaped hole micro gears 5 are obtained by slow wire electrical discharge slitting. The length requirement of each gear part of the D-shaped hole micro gear 5 is L0 = 1.5 mm, that is, the machining of the D-shaped hole micro gear parts is completed. It is used in cooperation with the vise to avoid repeated clamping during the clamping process and prevent errors caused by multiple clampings.

[0044] It should be noted that: Using the slow wire electrical discharge machining technology for slitting can achieve a relatively high degree of automation. By programming to control the machining path and parameters, batch machining can be realized, further improving production efficiency. The slow wire electrical discharge machining technology can produce a lower surface roughness, making the machining surfaces of multiple single pieces of D-shaped hole micro gears 5 smoother. Compared with traditional mechanical machining methods, the slow wire electrical discharge machining technology does not produce a heat-affected zone, thus avoiding machining errors caused by thermal deformation, which is of great significance for ensuring the machining accuracy and shape stability of the gears.

[0045] The present invention also claims protection for a processing tooling for D-shaped hole micro-gears. The processing tooling 6 for D-shaped hole micro-gears processes D-shaped hole micro-gears using any of the above methods. (As shown in Figure 6) The processing tooling 6 for D-shaped hole micro-gears is composed of a clamping block 601 and a set screw 602. The clamping block 601 has a square structure, and a block through-hole 6011 is made in its center. The block through-hole 6011 concentrically locates and clamps the long optical axis section 103 of the shaft gear blank 1. With the center of the block through-hole 6011 as the axis of symmetry, the clamping block 601 is provided with axially symmetric locking screw holes 6012. The center line of the locking screw holes 6012 is perpendicular to the center line of the block through-hole 6011. The locking screw holes 6012 are screwed with a suitable set screw 602, and the set screw 602 is used to lock the position of the long optical axis section 103. The inner shaft end face of the long optical axis section 103 is closely attached to the body of the clamping block 601 to increase stability.

[0046] Specifically: When using the processing tooling 6 for D-shaped hole micro-gears to clamp the long optical axis section 103, the block through-hole 6011 φ3H6 in the processing tooling 6 for D-shaped hole micro-gears and the outer circle φ3h7 of the long optical axis section 103 have a small clearance fit to ensure the coaxiality of the tooling and the shaft gear blank 1. The design of this fit accuracy is to facilitate the quick positioning of the tooling and the shaft gear blank 1 to ensure their coaxiality and concentricity. The 2-M2 locking screw holes 6012 facilitate the installation of two set screws 602 here after the shaft gear blank 1 and the tooling are coaxial, so as to ensure the axial fastening and non-movement of the shaft gear blank 1 and the tooling.

[0047] It should be noted that: A block through-hole 6011 is made in the center of the clamping block 601, and this block through-hole 6011 is used to concentrically locate and clamp the long optical axis section 103 of the shaft gear blank 1. This design ensures the accurate position of the shaft gear blank during the processing, helps to reduce the processing error, and improves the processing accuracy. With the center of the block through-hole 6011 as the axis of symmetry, the clamping block 601 is provided with axially symmetric locking screw holes 6012. This design enables the set screw 602 to lock the position of the long optical axis section 103 evenly and stably, further improving the clamping stability and accuracy. The locking screw holes 6012 are screwed with a suitable set screw 602, and the set screw 602 is used to lock the position of the long optical axis section 103. This locking method is not only simple and effective, but also can ensure that the shaft gear blank 1 does not move or shake during the processing, thus improving the processing stability. The inner shaft end face of the long optical axis section 103 is closely attached to the body of the clamping block 601. This design further increases the clamping stability. Through the close attachment of the shaft end face and the body of the clamping block, the loosening or offset of the shaft gear blank during the processing can be effectively prevented. The structure of the tooling is simple and clear, and the operation is convenient. Workers can quickly complete the clamping and positioning work of the shaft gear blank, thus improving the production efficiency.

[0048] In the above embodiments, further: The tooling is quenched to increase its hardness, without wear, and can be reused. Quenching is an important heat treatment process. By rapidly cooling a high-temperature workpiece, a phase transformation occurs on its surface layer or throughout the workpiece, forming a high-hardness structure. For tooling, quenching treatment can significantly increase its hardness and enhance its ability to resist external forces. Since the quenching treatment increases the hardness of the tooling, it becomes more wear-resistant. During the processing, the friction and wear between the tooling and the workpiece are effectively reduced, thereby extending the service life of the tooling. The tooling after quenching treatment can be reused multiple times without frequent replacement due to increased hardness and enhanced wear resistance. This helps improve the economy of the tooling and reduce production costs.

[0049] From the above description, it can be found that: The present invention prepares the blank through processes such as forging to ensure that the gear shaft has high strength and stiffness, providing a solid foundation for subsequent processing; Hobbing is a continuous process without idle strokes, with high production efficiency, and it is easy to ensure that the processed gear has a relatively accurate pitch, suitable for processing gears with small cumulative error requirements for adjustment; The electric pulse machine tool has a machining accuracy of the μm level, suitable for processing high-precision small workpieces; The surface finish can reach 0.1 Ra, meeting the high requirements for surface quality of micro-gears; The wire cut electrical discharge machining has a high machining accuracy level, generally able to reach the 0.001 mm level or even higher, ensuring the accuracy of the D-shaped hole; During the slitting process, the wire cut electrical discharge machining can maintain high precision to ensure that each micro-gear meets the design requirements; The connection between each process is tight and the process is smooth, improving production efficiency.

[0050] In the present invention, the short optical axis section 101 and the long optical axis section 103 are used as the clamping and positioning reference. Using a unified positioning reference and tolerance grade requirements, the quality is stable and consistent, improving the consistency and reliability of the product.

[0051] The electric pulse machining center of the present invention has high-precision machining capabilities, which helps reduce the error accumulation in subsequent machining processes and improve the overall machining accuracy; The electric pulse machining center can flexibly adjust the position of the prefabricated hole to meet specific design requirements; The prefabricated hole is not concentric with the center of the shaft gear blank, which can reduce the stress concentration phenomenon to a certain extent. This helps extend the service life of the gear and reduce faults such as cracks and fractures caused by stress concentration.

[0052] The tooling of the present invention has a simple structure, convenient clamping, precise and stable cooperation; The tooling is quenched to increase its hardness, without wear, and can be reused, improving the economy of the tooling and reducing production costs.

[0053] In summary, the process of the present invention has good processability, is easy to operate, and has high processing efficiency, making it suitable for popularization. Based on the traditional method of processing only one part at a time, the present invention can process five finished products, improving efficiency and saving costs. It is applicable to the processing of micro gears and small gears in watches, with a wide range of applications.

[0054] Each embodiment in this specification is described in a related manner. For the same or similar parts among the embodiments, reference can be made to each other, and the key point of each embodiment is to illustrate the differences from other embodiments.

[0055] The above description is only a preferred embodiment of the present invention and is not intended to limit the protection scope of the present invention. Any modifications and equivalent replacements made within the spirit and principle of the present invention are included in the protection scope of the present invention.

Claims

1. A method for machining a D-shaped hole micro gear, characterized in that: First, process the blank of the shaft gear (1) according to the shaft gear processing technology. Secondly, use the hobbing process to machine the tooth part (2). Then, use an electric pulse machining center to machine the prefabricated hole (3). Next, use a slow wire cutting machine to machine the D-shaped hole (4). Finally, use a slow wire cutting machine to cut and obtain multiple single-piece D-shaped hole micro-gears (5).

2. The method according to claim 1, wherein The steps are as follows: S1. Manufacture the blank of the shaft gear: The obtained blank of the shaft gear (1) consists of a short smooth shaft section (101), an intermediate smooth shaft section (102), and a long smooth shaft section (103) that are integrally formed coaxially. Among them, the diameters of the long and short smooth shaft sections (103, 101) are equal and smaller than the diameter of the intermediate smooth shaft section (102); the diameter of the intermediate smooth shaft section (102) matches the diameter of the D-shaped hole micro-gear (5); the axial length of the intermediate smooth shaft section (102) matches the thickness of multiple D-shaped hole micro-gears (5); the axial length of the short smooth shaft section (101) is smaller than the axial length of the intermediate smooth shaft section (102); the length of the long smooth shaft section (103) is greater than the axial length of the intermediate smooth shaft section (102). S2. Machine the teeth: Use the hobbing process to machine the intermediate smooth shaft section (102) to obtain the tooth part (2) of the D-shaped hole micro-gear (5). S3. Cut short: Cut short the short smooth shaft section (101) so that the axial length of the cut short short smooth shaft section (101) ≤ 2 mm. S4. Machine the prefabricated hole: Use an electric pulse machining center to machine an axially penetrating prefabricated hole (3), and make the center of the prefabricated hole (3) non-concentric with the center of the shaft gear blank (1). S5. Machine the D-shaped hole: Clamp and press the D-shaped hole micro-gear processing tooling (6) with a vise onto the flat plate of the slow wire cutting machine. Use the D-shaped hole micro-gear processing tooling (6) to clamp the long smooth shaft section (103). After threading, use a slow wire cutting electrical discharge wire cutting to machine the D-shaped hole (4). S6. Cut and separate: Rotate the D-shaped hole micro-gear processing tooling (6) clamped with a vise and the shaft gear blank (1) clamped by the D-shaped hole micro-gear processing tooling (6) together by 90°. After using a slow wire cutting electrical discharge to cut off the short smooth shaft section (101), use a slow wire cutting electrical discharge to cut and separate to obtain multiple single-piece D-shaped hole micro-gears (5).

3. The method according to claim 1 or 2, characterized in that: The module m of the D-shaped hole micro gear (5) is m ≤ 0.3 mm, the number of teeth Z ≤ 20, the inner hole diameter ≤ 3 mm and it is a D-shaped hole, and the gear width L0(1.5 +0.1 ) ≤ 2 mm.

4. The method according to claim 2, wherein: The short smooth shaft section (101) and the long smooth shaft section (103) are the clamping and positioning references during the tooth machining in step S2, the prefabricated hole machining in step S4, the D-shaped hole machining in step S5, and the cutting and separation in step S6; the outer circle tolerance grade accuracy requirements of the short smooth shaft section (101) and the long smooth shaft section (103) are not lower than h7.

5. The method according to claim 1 or 2, characterized in that: The accuracy requirement of the tooth part (2) is not lower than grade 6.

6. The method according to claim 1 or 2, characterized in that: The diameter of the prefabricated hole (3) is φ0.3 - 0.5 mm; the eccentricity between the center of the prefabricated hole (3) and the center of the shaft gear blank (1) is 0.5 mm.

7. A processing tooling for D-shaped hole micro-gears, characterized in that: The D-shaped hole micro gear processing tooling (6) processes the D-shaped hole micro gear by using the method described in any one of claims 1-6. The D-shaped hole micro gear processing tooling (6) consists of a clamping block (601) and a setscrew (602). The clamping block (601) has a square structure, and a block through hole (6011) is made in the center thereof. The long optical axis section (103) of the shaft gear blank (1) is concentrically positioned and clamped in the block through hole (6011). Taking the center of the block through hole (6011) as the axis of symmetry, the clamping block (601) is provided with axially symmetric locking screw holes (6012). The center line of the locking screw hole (6012) is perpendicular to the center line of the block through hole (6011). The locking screw hole (6012) is screwed with a suitable setscrew (602), and the setscrew (602) is used to lock the position of the long optical axis section (103). The inner shaft end face of the long optical axis section (103) is closely attached to the block body of the clamping block (601).

8. The tooling according to claim 7, wherein: The tooling is quenched to improve its hardness.

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