Automobile transmission gear machining method and clamp thereof

Abstract

The invention provides an automobile transmission gear machining method and a clamp thereof, and relates to the technical field of gear machining. The automobile transmission gear machining method comprises the following steps that a turning and milling composite machine tool is adopted for machining, the left side of a gear tooth top circle of a to-be-machined gear is clamped, the right side of the gear tooth top circle of the to-be-machined gear, a gear right side end face structure, an inner hole structure and an inner hole left end face are turned, and then the direction is turned to clamp the right side of the gear tooth top circle of the to-be-machined gear; turning the left side of the addendum circle and the left side end face structure of the gear; performing hobbing on the tooth surface of the gear according to the left end surface of the inner hole and the inner hole positioning, removing burrs generated by hobbing by using a chamfering machine, and performing heat treatment after cleaning and blow-drying after chamfering; and clamping the gear by adopting a clamp with a circular ring clamping piece which is consistent with the maximum outer diameter of the gear, and then carrying out hard turning on the gear subjected to heat treatment, and turning an inner hole, an inner hole left end surface and an inner hole right end surface. The technical effect of improving the working efficiency is achieved.

Description

Technical Field

[0001] This invention relates to the field of gear processing technology, and more specifically, to a method for processing automotive transmission gears and a fixture thereof. Background Technology

[0002] Gears are mechanical components with teeth on their rims that continuously mesh to transmit motion and power. They are widely used in mechanical transmission and throughout the entire mechanical field. In gear transmission, gear precision is crucial for ensuring the transmission accuracy and stability of the system, and this precision is closely related to the gear machining methods. Typically, gear machining methods include: gear blank machining, tooth surface machining, heat treatment, and tooth surface finishing. When developing a process, different process schemes are often adopted depending on the gear structure, precision grade, production batch size, and production environment. However, in current technology, the pursuit of higher gear precision and strength has led to complex gear machining processes, resulting in low production efficiency. Summary of the Invention

[0003] The purpose of this invention is to provide a method for processing automotive transmission gears and a fixture thereof, so as to alleviate the technical problem of low gear production efficiency in the prior art.

[0004] In a first aspect, embodiments of the present invention provide a method for machining automotive transmission gears, comprising the following steps: The gear is machined using a milling and turning machine tool. The left side of the addendum circle of the gear is clamped, and the right side of the addendum circle, the right end face structure, the inner hole structure, and the left end face of the inner hole are machined. Then the direction is reversed, the right side of the addendum circle of the gear is clamped, and the left side of the addendum circle and the left end face structure of the gear are machined. Based on the left end face of the inner hole and the positioning of the inner hole, the tooth surface of the gear is hobbed. The burrs generated by the hobbing are removed by a chamfering machine. After chamfering, the gear is cleaned, dried, and then heat-treated. The gear is clamped using a jig with a ring clamping part that matches the maximum outer diameter of the gear. Then, the heat-treated gear is hard-turned to turn the inner hole, the left end face of the inner hole, and the right end face of the inner hole. Then the mating teeth are welded to the right end face of the gear, and finally the tooth surface is precision machined.

[0005] In conjunction with the first aspect, the present invention provides a possible implementation of the first aspect, wherein the above-mentioned gear right end face structure includes a gear right end face, a right end face groove, and an outer circle; The left end face structure of the gear includes a left end face of the gear and a left end face groove; The internal structure includes an inner hole, the right end face of the inner hole, and oil grooves on both sides of the gear.

[0006] In conjunction with the first aspect, the present invention provides a possible implementation of the first aspect, wherein when re-clamping the gear to be processed in a reversed direction, a soft jaw is used for clamping, and the soft jaw is turned so that the inner diameter of the turned soft jaw is 0.1-0.5 mm larger than the outer diameter of the gear blank.

[0007] In conjunction with the first aspect, the present invention provides a possible implementation of the first aspect, wherein, during the above-mentioned processing, a heat-hardening allowance of 0.2 mm is left on the left end face and the right end face of the inner hole, and a heat-hardening allowance of 3 mm is left on the outer circle.

[0008] In conjunction with the first aspect, the present invention provides a possible implementation of the first aspect, wherein the above-mentioned turning process is divided into rough turning and finish turning. The rough turning cutting parameters are set to a machining line speed v = 180 m / min, a feed rate f = 0.3 mm / r, and a depth of cut ap = 1.5 mm; the finish turning cutting parameters are set to a machining line speed v = 250 m / min, a feed rate f = 0.12 mm / r, and a depth of cut ap = 0.5 mm.

[0009] In conjunction with the first aspect, the present invention provides a possible implementation of the first aspect, wherein the heat treatment includes the following conditions: the gear is heat treated by carburizing and quenching, the carburizing temperature is set to 960°C, the quenching temperature is set to 860°C, the hardened layer depth is required to be 0.5-0.8 (550HV1), the surface hardness is ≥680HV1, or the surface hardness is (80-83) HRA, and the core hardness is (320-450) HV30.

[0010] In conjunction with the first aspect, the present invention provides a possible implementation of the first aspect, wherein the machining parameters of the above-mentioned hard turning are: linear speed V = 150 m / min, depth of cut ap = 0.1 mm, and feed rate F = 0.05 mm / r.

[0011] In conjunction with the first aspect, the present invention provides a possible implementation of the first aspect, wherein, in the above-mentioned finishing process of the tooth surface, a gear grinding machine is used to grind the teeth, and a shrinking sleeve clamp is used to tighten the inner hole to complete the processing.

[0012] In conjunction with the first aspect, the present invention provides a possible implementation of the first aspect, wherein the grinding wheel of the above-mentioned gear grinding machine is a corundum grinding wheel with a grit size of 80 and a linear velocity V=35m / min.

[0013] Secondly, embodiments of the present invention provide an automotive transmission gear machining fixture for the automotive transmission gear machining method, comprising a base jaw, a positioning block, and a clamping block; The base claw is provided with a first mounting seat and a second mounting seat, the first mounting seat is higher than the second mounting seat, and the first mounting seat is located outside the second mounting seat; The clamping block is mounted on the first mounting base, and the positioning block is mounted on the second mounting base; Multiple clamping blocks are connected to form a ring, the diameter of which is consistent with the maximum outer diameter of the gear to be processed.

[0014] Beneficial effects: This invention provides a method for machining automotive transmission gears, comprising the following steps: using a milling and turning machine tool, clamping the left side of the addendum circle of the gear teeth, turning the right side of the addendum circle, the right end face structure, the inner hole structure, and the left end face of the inner hole; then reversing the direction, clamping the right side of the addendum circle of the gear teeth, and turning the left side of the addendum circle and the left end face structure of the gear; performing gear hobbing on the gear teeth according to the positioning of the left end face and the inner hole; using a chamfering machine to remove the burrs generated by the hobbing; after chamfering, cleaning and drying, and then heat treatment; clamping the gear with a jig having a ring clamping part consistent with the maximum outer diameter of the gear; then hard turning the heat-treated gear, turning the inner hole, the left end face of the inner hole, and the right end face of the inner hole; then welding the mating teeth onto the right end face of the gear; and finally finishing the gear teeth.

[0015] Specifically, the gear to be machined first undergoes sequential machining of the gear blank, rough machining of the gear surface, gear heat treatment, post-heat turning, welding of the gear teeth, and finish machining of the gear surface. A milling-turning machine is used for this process, allowing multiple operations, including turning, milling, drilling, and boring, to be completed on a single machine. This enables more machining processes to be completed in a single setup, improving production efficiency and reducing the number of setups. It also avoids error accumulation caused by multiple conversions of the positioning datum, thus improving machining accuracy. Furthermore, the inner end faces of both sides of the gear are machined during the gear blank machining and post-heat turning stages, effectively ensuring the subsequent machining accuracy of the gear. During the post-heat turning stage, a fixture with ring clamping elements matching the maximum outer diameter of the gear is used to clamp the gear. The multiple ring clamping elements on the fixture are cut from the same ring, thus providing a larger clamping area and increasing the force-bearing area of ​​the gear during clamping. This results in a more uniform clamping force, reducing gear deformation during clamping and better ensuring the gear's machining accuracy. This setup improves the gear machining efficiency.

[0016] This invention provides a machining fixture for automotive transmission gears, used in a method for machining automotive transmission gears. It includes a base jaw, a positioning block, and a clamping block. The base jaw has a first mounting seat and a second mounting seat, with the first mounting seat being higher than the second mounting seat and located outside the second mounting seat. The clamping block is mounted on the first mounting seat, and the positioning block is mounted on the second mounting seat. Multiple clamping blocks are connected to form a ring, the diameter of which is consistent with the maximum outer diameter of the gear to be machined. This automotive transmission gear machining fixture has the advantages described above compared to existing technologies, which will not be elaborated further here. Attached Figure Description

[0017] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0018] Figure 1 A flowchart of a method for machining automotive transmission gears provided in an embodiment of the present invention; Figure 2 A schematic diagram of an automotive transmission gear machining fixture provided in an embodiment of the present invention; Figure 3 This is a schematic diagram of the automotive transmission gear machining fixture clamping a gear according to an embodiment of the present invention; Figure 4 This is an internal schematic diagram of the automotive transmission gear machining fixture provided in an embodiment of the present invention; Figure 5 This is a half-sectional schematic diagram of the automotive transmission gear machining fixture provided in an embodiment of the present invention; Figure 6 A schematic diagram of a gear manufactured by the automotive transmission gear processing method provided in an embodiment of the present invention.

[0019] icon: 10-Gear; 11-Addition circle; 12-Left end face; 13-Right end face; 14-Inner hole; 141-Left end face of inner hole; 142-Right end face of inner hole; 15-Outer circle; 16-Left end face groove; 17-Right end face groove; 18-Oil groove; 100 - Base claw; 110 - First mounting base; 120 - Second mounting base; 200 - Positioning block; 210 - Elevation ring; 300 - Clamping block; 310 - Waist-shaped slot. Detailed Implementation

[0020] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0022] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0023] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0024] The present invention will now be described in further detail with reference to specific embodiments and accompanying drawings.

[0025] See Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 and Figure 6As shown, this embodiment provides a method for machining automotive transmission gears, including the following steps: A milling and turning machine is used to clamp the left side of the addendum circle 11 of the gear 10 to be machined, and the right side of the addendum circle 11, the right end face structure, the inner hole structure, and the left end face 141 of the inner hole are machined. Then, the direction is reversed, the right side of the addendum circle 11 of the gear 10 is clamped, and the left side of the addendum circle 11 and the left end face structure of the gear are machined. Based on the positioning of the left end face 141 and the inner hole 14, the tooth surface of the gear 10 is hobbed. A chamfering machine is used to remove the burrs generated by the hobbing. After chamfering, the gear is cleaned, dried, and then heat-treated. A fixture with a ring clamping element consistent with the maximum outer diameter of the gear 10 is used to clamp the gear 10. Then, the heat-treated gear 10 is hard-turned, and the inner hole 14, the left end face 141, and the right end face 142 of the inner hole are machined. Then, the mating teeth are welded onto the right end face 13 of the gear 10, and finally, the tooth surface is finished.

[0026] Specifically, the gear 10 to be machined first undergoes sequential machining of the gear blank, rough machining of the gear surface, heat treatment of the gear 10, post-heat turning, welding of the gear teeth, and finish machining of the gear surface. This process is performed using a milling-turning machine, which allows multiple operations, including turning, milling, drilling, and boring, to be completed on a single machine. This enables more machining operations to be completed in a single setup, improving production efficiency and reducing the number of setups. It also avoids error accumulation caused by multiple conversions of the positioning datum, thus improving machining accuracy. Furthermore, during the gear blank machining and post-heat turning stages, the end faces of the inner holes 14 on both sides of the gear 10 are... The design effectively ensures the subsequent machining accuracy of gear 10. During the post-heat turning stage, a fixture with ring clamping parts that match the maximum outer diameter of gear 10 is used to clamp gear 10. The multiple ring clamping parts on the fixture are cut from the same ring, so the clamping area of ​​gear 10 is larger. When gear 10 is clamped, the force-bearing area of ​​gear 10 is increased, making the clamping force on gear 10 more uniform and reducing the clamping deformation of gear 10. This better ensures the machining accuracy of gear 10. Through this design, the machining efficiency of gear 10 is improved.

[0027] The right end face structure of the gear includes the right end face 13 of the gear 10, the right end face groove 17 and the outer circle 15; the left end face structure of the gear includes the left end face 12 of the gear 10 and the left end face groove 16; the inner hole structure includes the inner hole 14, the right end face 142 of the inner hole and the oil grooves 18 on both sides of the gear 10.

[0028] When repositioning the gear 10 to be processed, a soft jaw is used for clamping, and the soft jaw is turned so that the inner diameter of the turned soft jaw is 0.1-0.5 mm larger than the outer diameter of the gear 10 blank.

[0029] Specifically, during the gear blank turning process, the gear 10 is turned using the clamping method of the three-jaw chuck of the milling and turning machine tool. First, the left side of the addendum circle 11 of the gear 10 is clamped, with the clamping position close to the left end face 12. The right side of the gear blank is then turned. The right side of the addendum circle 11 of the gear 10, the right end face 13 of the gear 10, the end face groove, the inner hole 14, the outer circle 15, the left end face 141 of the inner hole, and the right end face 142 of the inner hole are machined. Oil grooves 18 are milled on both sides of the gear 10. A 0.2mm heat-hardening allowance is left at the left end face 141 and the right end face 142 of the inner hole. The outer circle 15 is the position of the welded teeth after heat treatment. A 3mm heat-hardening allowance is left on the outer circle 15 to remove the carburized layer. During the above process, the end faces on both sides of the inner hole 14 and the inner hole 14 are machined. The runout of the inner hole 14 and the end faces on both sides of the inner hole 14 is controlled within 0.005, which can better ensure the machining accuracy of the gear 10 and the accuracy of the mating teeth after welding.

[0030] The left end of the inner hole 14 near the chuck jaws can be machined using an inner hole hook tool.

[0031] Then, turn the left side of the gear blank 10, clamp the right side of the addendum circle 11 of the gear 10, and clamp the gear 10 close to the right end face 13. Turn the left end face 12 of the gear 10, the left side of the addendum circle 11, and the end face groove to the required dimensions. When turning the left side of the gear blank 10, use soft jaws to hold the gear 10 and turn the soft jaws so that the inner diameter of the turned soft jaws is 0.1-0.5mm larger than the outer diameter of the blank, and the runout of the three jaws is within 0.004, to ensure the runout, flatness, and dimensional accuracy of the gear 10.

[0032] The turning process for the gear blank is divided into rough turning and finish turning. The rough turning cutting parameters are set as follows: machining speed v = 180 m / min, feed rate f = 0.3 mm / r, and depth of cut ap = 1.5 mm. The finish turning cutting parameters are set as follows: machining speed v = 250 m / min, feed rate f = 0.12 mm / r, and depth of cut ap = 0.5 mm.

[0033] After the gear blank is machined, the tooth surface of the gear 10 is rough machined using a gear hobbing machine, with the left end face 141 of the inner hole and the inner hole 14 as the positioning for gear hobbing. After gear hobbing, the teeth are chamfered and deburred. The burrs generated by gear hobbing are removed using a chamfering machine. After chamfering, the gear 10 is cleaned and dried, and then the gear 10 is heat treated.

[0034] Specifically, the heat treatment includes the following conditions: the gear 10 is heat-treated by carburizing and quenching, with the carburizing temperature set at 960℃ and the quenching temperature set at 860℃. The hardened layer depth is required to be 0.5-0.8 (550HV1), the surface hardness is ≥680HV1, or the surface hardness is (80-83) HRA, the core hardness is (320-450) HV30, and no impurities are left on the surface after heat treatment. This setting can effectively improve the deformation of the parts and increase the hardness and wear resistance of the gear 10.

[0035] In the optional scheme of this embodiment, the machining parameters of the hard turning are: linear speed V=150m / min, depth of cut ap=0.1mm, and feed rate F=0.05mm / r.

[0036] Specifically, after the gear 10 has undergone heat treatment, it is hard-turned. The gear 10 is clamped using the automotive transmission gear machining fixture provided in this embodiment. The left side of the addendum circle 11 of the gear 10 is pressed against the left end face 12. The inner hole 14, the left end face 141 of the inner hole, and the right end face 142 of the inner hole are machined. The clamping block 300 used to hold the gear 10 on the automotive transmission gear machining fixture provided in this embodiment is made by cutting a ring into three equal parts. The diameter of the inner hole 14 of the ring of the clamping block 300 is the maximum outer diameter of the gear 10. Therefore, when multiple clamping blocks 300 hold the gear 10, the clamping position of the gear 10 can be larger, basically clamping the entire circle. When the gear 10 is clamped, the force-bearing area of ​​the gear 10 is increased, making the clamping force on the gear 10 more uniform, reducing the clamping deformation of the gear 10, and thus better ensuring the machining accuracy of the gear 10.

[0037] In this embodiment, when installing the automotive transmission gear machining fixture, the base jaw 100 is first installed and then self-machined. This eliminates the positioning accuracy difference caused by repeated installation of the base jaw 100, and better ensures the positioning accuracy requirements of the base jaw 100. This arrangement ensures the perpendicularity of the self-machined position of the base jaw 100 to its self-machined end face. It also ensures the perpendicularity requirements between the clamping block 300 and the positioning block 200. Furthermore, the two ends of the positioning block 200 are flat ground to ensure its parallelism.

[0038] It should be noted that the automotive transmission gear machining fixture provided in this embodiment can sequentially clamp and complete the hard turning of the inner hole 14 and both end faces, reducing the step of disassembling and flipping the gear 10 for re-clamping. Unlike traditional turning methods, which require first turning one side of the inner hole 14 end face and the inner hole 14, and then turning the other side of the inner hole 14 end face using a custom-made fixture, this method reduces a turning step, decreases fixture customization costs and time, prevents precision loss due to re-clamping, and better ensures the precision requirements of subsequent gear grinding and welding. Furthermore, by using the automotive transmission gear machining fixture provided in this embodiment, the machining datum of the inner hole 14 end face and the inner hole 14 is unified. During the post-heat hard turning stage, the inner hole 14 and both end faces of the gear 10 can be machined in one clamping operation, effectively avoiding errors caused by repeated clamping, thereby improving machining accuracy and reducing the time spent on repeated clamping.

[0039] It should also be noted that the clamping part of the automotive transmission gear processing fixture provided in this embodiment is the tooth tip circle 11, and the clamping block 300 and the positioning block 200 will not contact the two end faces of the gear 10. Therefore, they will not be affected by the protrusions or small burrs on the two end faces of the gear 10 caused by chamfering and other processing.

[0040] The machining parameters for hard turning are: linear speed V = 150 m / min, depth of cut ap = 0.1 mm, and feed rate F = 0.05 mm / r. With these settings, the cylindricity of gear 10 after hot turning can reach 0.005, the surface roughness can reach 0.8 Ra, and the runout of the two end faces of the inner hole 14 can reach the accuracy requirements of 0.005.

[0041] Specifically, after the hot turning is completed, the gear 10 is welded with a mating tooth. The weld depth between the mating tooth and the outer circle 15 is not less than 3.5 mm, calculated from the surface of the part. The cumulative total deviation of the spline pitch of the mating tooth is less than 0.1 mm. Under a torque of 1750 Nm, the mating tooth and the gear 10 must not separate.

[0042] It should be noted that the mating teeth and gear 10 are machined separately and then welded together. Welding the mating teeth can be done in two ways: pre-heat welding and post-heat welding. Pre-heat welding is performed when the size of the mating teeth is smaller than the size of gear 10, without affecting the subsequent grinding of gear 10. When the size of the mating teeth is larger than the size of gear 10, pre-heat welding will cause interference between the mating teeth and the grinding wheel during the grinding process, making grinding impossible. In this case, gear 10 and the mating teeth need to be heat-treated separately, and then the gear 10 is welded to the mating teeth after the grinding process is completed.

[0043] In an optional embodiment, during the finishing process of the tooth surface, a gear grinding machine is used to grind the teeth, and a tensioning clamp is used to tighten the inner hole 14 to complete the machining.

[0044] Specifically, the teeth are ground using a gear grinding machine, and the inner hole 14 is tightened using a tensioning clamp to complete the machining. The clamping accuracy is controlled within 0.003mm. A corundum grinding wheel with a grit size of 80 and a linear speed of V=35m / min is selected to meet the accuracy requirements of radial runout Fr0.026, tooth tip trimming amount of 0.005mm±0.004mm, and surface roughness Ra0.4.

[0045] One advantage of using a gear grinding machine is that the grinding wheel can be modified according to the drawings to achieve fine machining of the tooth surface of small batches of diverse gears 10, without the need to customize a special grinding wheel for each part.

[0046] In addition, after grinding, the parts need to be subjected to strong shot peening. The residual compressive stress in the subsurface layer 25μm of the tooth surface and tooth root after shot peening should not be less than 800MPa, and the shot peening coverage should be greater than 100%.

[0047] See Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 and Figure 6 As shown, this embodiment provides a machining fixture for automotive transmission gears, used in a method for machining automotive transmission gears. It includes a base jaw 100, a positioning block 200, and a clamping block 300. The base jaw 100 has a first mounting seat 110 and a second mounting seat 120, with the first mounting seat 110 being higher than the second mounting seat 120, and the first mounting seat 110 located outside the second mounting seat 120. The clamping block 300 is mounted on the first mounting seat 110, and the positioning block 200 is mounted on the second mounting seat 120. Multiple clamping blocks 300 are connected to form a ring, the diameter of which is consistent with the maximum outer diameter of the gear 10 to be machined.

[0048] Specifically, the clamping block 300 used to hold the gear 10 is made by cutting a ring into three equal parts. The diameter of the inner hole 14 of the ring of the clamping block 300 is the maximum outer diameter of the gear 10. Therefore, when multiple clamping blocks 300 hold the gear 10, the position of the gear 10 can be larger, basically holding the entire circle. When the gear 10 is clamped, the force-bearing area of ​​the gear 10 is increased, making the clamping force on the gear 10 more uniform, reducing the clamping deformation of the gear 10, and thus better ensuring the machining accuracy of the gear 10.

[0049] In addition, the clamping block 300 is provided with a waist-shaped slot 310. By setting the waist-shaped slot 310, the position of the clamping block 300 on the first mounting base 110 can be finely adjusted.

[0050] It should be noted that a lifting ring 210 is provided on the positioning block 200, and the positioning hole is not in contact with the chamfer on the end face of the gear 10 by the setting of the lifting ring 210.

[0051] The automotive transmission gear processing fixture provided in this embodiment has advantages over the aforementioned automotive transmission gear processing method compared to the prior art, which will not be elaborated here.

[0052] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for machining automotive transmission gears, characterized in that, Includes the following steps: The gear (10) is machined using a milling and turning machine tool. The left side of the tooth tip circle (11) of the gear (10) to be machined is clamped, and the right side of the tooth tip circle (11), the right end face structure, the inner hole structure and the left end face (141) of the inner hole of the gear (10) are machined. Then the direction is reversed, the right side of the tooth tip circle (11) of the gear (10) to be machined is clamped, and the left side of the tooth tip circle (11) and the left end face structure are machined. Based on the positioning of the left end face (141) of the inner hole and the inner hole (14), the tooth surface of the gear (10) is hobbed. The burrs generated by the hobbing are removed by a chamfering machine. After chamfering, the gear is cleaned and dried before heat treatment. The gear (10) is clamped by a jig with a ring clamping member that is consistent with the maximum outer diameter of the gear (10), and then the heat-treated gear (10) is hard-turned to turn the inner hole (14), the left end face (141) of the inner hole and the right end face (142) of the inner hole. Then the connecting teeth are welded onto the right end face (13), and finally the tooth surface is finished.

2. The method for machining automotive transmission gears according to claim 1, characterized in that, The right end face structure includes a right end face (13), a right end face groove (17), and an outer circle (15); The left end face structure includes a left end face (12) and a left end face groove (16). The inner hole structure includes an inner hole (14), the right end face (142) of the inner hole, and oil grooves (18) on both sides of the gear (10).

3. The method for machining automotive transmission gears according to claim 2, characterized in that, When reversing the direction and re-clamping the gear (10) to be processed, use soft jaws to clamp it and turn the soft jaws so that the inner diameter of the turned soft jaws is 0.1-0.5 mm larger than the outer diameter of the gear (10) blank.

4. The method for machining automotive transmission gears according to claim 3, characterized in that, During the machining process, a heat-hardening allowance of 0.2 mm is left on the left end face (141) and the right end face (142) of the inner hole, and a heat-hardening allowance of 3 mm is left on the outer circle (15).

5. The method for machining automotive transmission gears according to claim 4, characterized in that, The turning process is divided into roughing and finishing. The roughing cutting parameters are set as follows: machining speed v = 180 m / min, feed rate f = 0.3 mm / r, and depth of cut ap = 1.5 mm. The finishing cutting parameters are set as follows: machining speed v = 250 m / min, feed rate f = 0.12 mm / r, and depth of cut ap = 0.5 mm.

6. The method for machining automotive transmission gears according to claim 1, characterized in that, The heat treatment includes the following conditions: the gear (10) is heat-treated by carburizing and quenching, the carburizing temperature is set to 960℃, the quenching temperature is set to 860℃, the hardened layer depth is required to be 0.5-0.8 (550HV1), the surface hardness is ≥680HV1, or the surface hardness is (80-83) HRA, and the core hardness is (320-450) HV30.

7. The method for machining automotive transmission gears according to claim 1, characterized in that, The machining parameters for hard turning are: linear speed V = 150 m / min, depth of cut ap = 0.1 mm, and feed rate F = 0.05 mm / r.

8. The method for machining automotive transmission gears according to claim 1, characterized in that, During the finishing process of the tooth surface, a gear grinding machine is used to grind the teeth, and a clamping device is used to tighten the inner hole (14) to complete the machining.

9. The method for machining automotive transmission gears according to claim 8, characterized in that, The grinding wheel of the gear grinding machine is an alumina grinding wheel with a grit size of 80 and a linear velocity of V=35m / min.

10. A machining fixture for automotive transmission gears, used in the automotive transmission gear machining method according to any one of claims 1-9, characterized in that, include: Base claw (100), positioning block (200) and clamping block (300); The base claw (100) is provided with a first mounting seat (110) and a second mounting seat (120). The height of the first mounting seat (110) is higher than that of the second mounting seat (120), and the first mounting seat (110) is located outside the second mounting seat (120). The clamping block (300) is mounted on the first mounting base (110), and the positioning block (200) is mounted on the second mounting base (120); Multiple clamping blocks (300) are connected to form a ring, the diameter of which is consistent with the maximum outer diameter of the gear (10) to be processed.

Images