A grinding wheel for machining the circlip groove of a gear shaft and its manufacturing method.

Abstract

This invention proposes a grinding wheel for machining circlip grooves on gear shafts and its manufacturing method. The grinding wheel includes a grinding wheel steel base, and the outer cylindrical surface of the grinding wheel steel base is provided with multiple grinding teeth that correspond one-to-one with the circlip grooves on the gear shaft to be machined. Each grinding tooth is electroplated with a single layer of superhard abrasive, and the number of grinding teeth is the same as the number of circlip grooves on the gear shaft to be machined. By providing multiple grinding teeth on the outer cylindrical surface of the grinding wheel steel base that correspond one-to-one with the circlip grooves on the gear shaft to be machined, this invention achieves the precision forming grinding of all circlip grooves by having all grinding teeth participate in grinding simultaneously in one feed and completing the grinding of all circlip grooves in one retraction. This completely changes the traditional serial mode of turning, which requires interpolation machining one by one. The grinding cycle time of 1 to 12 circlip grooves on the entire gear shaft is significantly shortened, and the production efficiency is significantly improved compared with traditional turning, greatly reducing the processing time per piece and significantly reducing time and labor costs.

Description

Technical Field

[0001] This invention relates to the field of abrasive processing technology, and in particular to a grinding wheel for machining gear shaft snap ring grooves and its manufacturing method. Background Technology

[0002] With social development and the improvement of people's living standards, new energy vehicles have become the main direction for the future development of the automotive industry. At the same time, with the continuous advancement of high-end manufacturing technology, the processing and manufacturing capabilities of various precision components for new energy vehicles have been significantly improved.

[0003] As a key component in new energy vehicle transmissions for achieving high-speed, precision transmission, the gear shaft's machining accuracy and product quality directly determine the vehicle's driving and safety performance. New energy vehicle transmissions now have maximum input speeds exceeding 9000 r / min, placing higher demands on transmission accuracy and smoothness, requiring gearbox gears to achieve a precision level of 4-6. The various circlip grooves on the gear shaft play a crucial role in precision positioning and are a core structure ensuring the accurate assembly of components such as gears, bearings, and synchronizer hubs. Therefore, high precision is required for their groove dimensions and tooth pitch, which is closely related to the gear shaft circlip groove machining process.

[0004] Currently, the machining of circlip grooves on gear shafts is mostly done by turning, that is, using multiple cutting tools on a CNC lathe to successively turn multiple circlip grooves (1 to 15) on the gear shaft. The typical process flow includes: the first step is to turn the circlip groove area, with the tool allocation as follows... Figure 1 As shown, different cutting tools are used to interpolate and machine multiple circlip grooves; the second step involves turning the remaining circlip grooves, with the tool allocation as follows. Figure 2 As shown.

[0005] However, this type of turning process has the following prominent problems:

[0006] 1. Long machining cycle and low production efficiency. Multiple circlip grooves on the gear shaft need to be individually interpolated and turned, involving multiple tool holders changing tools back and forth to machine different parts of the circlip grooves. Depending on the number and complexity of the circlip grooves on the gear shaft, the machining time for a single gear shaft circlip groove ranges from 3 to 20 minutes, with an average machining cycle of more than 10 minutes. To meet the ever-increasing order demand, manufacturers have to invest more space, equipment, and human resources, significantly increasing manufacturing costs.

[0007] 2. Short tool life and frequent tool changes. Due to limitations in insert material, wear resistance, and impact toughness, the average machining life of each lathe tool insert is only about 500 pieces. Since multiple inserts reach the end of their lifespan at different times, frequent machine stops are required to replace them. Furthermore, after each insert replacement, the machine must be stopped again to await inspection results, further reducing overall machining efficiency. In addition, if the circlip groove is machined after heat treatment, the uneven hardness at the circlip groove can cause the hard-turning tool to chip easily.

[0008] 3. Limited improvement in surface finish. Currently, the surface roughness of the turned circlip groove end face is generally between Ra0.8 and Ra1.6, and the turning marks are quite obvious. For the increasingly stringent surface quality requirements of precision parts under the high-speed operating conditions of new energy vehicles, the improvement potential of turning is extremely limited.

[0009] In addition, some process routes use grinding to process the snap ring groove, but traditional grinding is mostly single-groove grinding, which is also not very efficient.

[0010] The aforementioned problems severely restrict the machining efficiency and surface quality of the circlip grooves on the gear shafts of new energy vehicle transmissions. Therefore, there is an urgent need to develop a solution that can achieve efficient and precise machining of the circlip grooves on the gear shafts. Summary of the Invention

[0011] To address the aforementioned technical problems, this invention proposes a grinding wheel for machining the snap ring groove of a gear shaft and its manufacturing method, which solves the problems of low machining efficiency, poor surface quality, and short tool life in the existing technology for machining the snap ring groove of a gear shaft by grinding a single groove sequentially.

[0012] To achieve the above objectives, the technical solution of the present invention is implemented as follows:

[0013] A grinding wheel for machining snap ring grooves on a gear shaft includes a steel base. The outer cylindrical surface of the steel base is provided with multiple grinding teeth corresponding one-to-one with the snap ring grooves on the gear shaft to be machined. Each grinding tooth is electroplated with a single layer of superhard abrasive. The number of grinding teeth is the same as the number of snap ring grooves on the gear shaft to be machined. This invention, by providing multiple grinding teeth corresponding one-to-one with the snap ring grooves on the outer cylindrical surface of the steel base, achieves precision forming grinding of all snap ring grooves in a single feed, completing the grinding of all grooves in a single withdrawal. This completely changes the traditional sequential turning process that requires interpolation and machining one by one. The grinding cycle time for 1 to 12 snap ring grooves on the entire gear shaft is significantly shortened, resulting in significantly improved production efficiency compared to traditional turning, greatly reducing the processing time per piece, and significantly lowering time and labor costs.

[0014] Furthermore, in order to address the working conditions where the grinding allowance is uniform, there is no intermittent grinding, and the wear rate of each tooth is consistent, the particle size of the superhard abrasive on different grinding teeth of the same grinding wheel is the same.

[0015] Furthermore, in order to achieve a balanced matching of the wear rates of each tooth under working conditions where different grinding teeth have different wear rates, the particle size of the superhard abrasive on the same grinding wheel for different grinding teeth is different.

[0016] Furthermore, in order to improve the overall service life of the grinding wheel, the superhard abrasive electroplated on the surface of the grinding teeth corresponding to the large grinding allowance and / or the intermittent grinding parts is coarse abrasive; the superhard abrasive electroplated on the surface of other grinding teeth is fine abrasive.

[0017] Furthermore, in order to ensure that the grinding wheel matrix has sufficient strength and toughness to withstand the load during the grinding process, the grinding wheel steel matrix is ​​made of 40Cr or 42CrMo, and the tempering hardness is HRC28~35.

[0018] Furthermore, in order to ensure the spatial positional accuracy of each grinding tooth so that all teeth can participate in grinding simultaneously, the end face runout of the grinding wheel steel base is ≤0.005mm, and the flatness is ≤0.005mm.

[0019] A method for manufacturing a grinding wheel for high-efficiency machining of gear shaft snap ring grooves includes the following steps: (1) Grinding wheel base blank preparation: Grinding wheel base blank is prepared using 40Cr or 42CrMo forgings, and the hardness is quenched and tempered to HRC28~35; (2) Semi-finishing of grinding wheel base: The grinding wheel base blank is rough turned on a lathe, ground to the required thickness on a surface grinder, and ground to the required size on an internal cylindrical grinder, so that the end face runout is ≤0.005mm, the flatness is ≤0.005mm, and the roughness Ra is ≤0.8μm; (3) Finish turning of grinding wheel base: CNC machining is performed on the grinding wheel base blank. The lathe is used to turn the mandrel online, and the grinding wheel is installed and pressed. The outer cylindrical surface of the grinding wheel base is precision turned to form the base surface of multiple grinding teeth that correspond one-to-one with the circlip groove of the gear shaft to be processed; (4) Electroplating superhard abrasive: Electroplating a single layer of superhard abrasive on each grinding tooth in the outer cylindrical surface area of ​​the grinding wheel base, with the abrasive embedment rate controlled in the range of 45% to 60%; (5) Outer cylindrical abrasive layer dressing: Precision dressing of the abrasive layer of each grinding tooth so that the profile size and distance size of each grinding tooth meet the product size design requirements; (6) Dynamic balancing treatment: Dynamically balancing the grinding wheel to meet the requirements. This invention, through the aforementioned manufacturing method, employs a single-layer electroplated superhard abrasive as the working layer of the grinding teeth. The abrasive exhibits high bonding strength and excellent wear resistance with the grinding wheel substrate. The abrasive embedment rate is controlled within the range of 45% to 60%, ensuring a balance between the abrasive holding strength and the chip space. Precision dressing ensures that the profile dimensions and distance dimensions of each grinding tooth meet design requirements. Dynamic balancing ensures the stability of the grinding wheel during high-speed rotation, effectively avoiding the waste of time spent on frequent machine stops for tool changes and waiting for inspection, reducing the labor intensity of operators, and further improving overall processing efficiency.

[0020] Furthermore, in order to ensure the consistency of the profile size and distance size when multiple teeth participate in grinding at the same time, in step (3), the runout of the grinding wheel base end face after precision turning is ≤0.003mm, the radial runout of the inner hole is ≤0.003mm, and the distance size between the base teeth deviates from the standard size by ≤±0.005mm.

[0021] Furthermore, in order to achieve reliable electroplating of superhard abrasives of different particle sizes on the same grinding wheel substrate, in step (4), the electroplating of superhard abrasives of different particle sizes adopts a step-by-step masking electroplating process, specifically including: First step, the grinding teeth with pre-set fine abrasive are electroplated and masked using a masking fixture, and a layer of coarse abrasive is planted on the grinding teeth with pre-set coarse abrasive, and the electroplating thickening begins; Second step, when the coarse abrasive embedding rate reaches the range of 20% to 35%, the masking fixture in the first step is removed, and a layer of fine abrasive is planted on the grinding teeth with pre-set fine abrasive, and the overall electroplating thickening continues; Third step, when the embedding rates of fine abrasive and coarse abrasive of all grinding teeth meet the range of 45% to 60%, the electroplating thickening is stopped.

[0022] A grinding method for gear shaft snap ring grooves employs the grinding wheel described in any one of claims 1 to 4. In a single feed, all grinding teeth on the grinding wheel simultaneously participate in grinding the corresponding snap ring grooves. After the grinding process exits, all snap ring grooves to be processed are ground in one pass. This invention utilizes the above-mentioned grinding method, eliminating the need for wheel dressing during the grinding process. The surface dimensions of the single-layer electroplated superhard abrasive remain stable over a long period after electroplating and precision dressing, resulting in good dimensional consistency in batch processing. No tool compensation adjustments are required during the process, significantly improving the quality stability and yield of mass production. Simultaneously, the surface roughness achieved can reach Ra0.32μm to Ra0.4μm, far superior to the Ra0.8μm to Ra1.2μm of traditional turning, stably meeting the stringent requirements of Ra0.8 and below for the surface quality of precision parts under high-speed operating conditions in new energy vehicles.

[0023] The beneficial effects of this invention are:

[0024] 1. The grinding wheel for high-efficiency machining of circlip grooves on gear shafts provided by this invention, by setting multiple grinding teeth on the outer cylindrical surface of the grinding wheel base that correspond one-to-one with the circlip grooves of the gear shaft to be machined, achieves the simultaneous participation of all grinding teeth in grinding during one feed and completes the precision forming grinding of all circlip grooves in one retraction, completely changing the serial mode of traditional turning which requires interpolation machining one by one. As shown in Examples 1 to 3, the grinding cycle time for 5 to 12 circlip grooves on the entire gear shaft is only 40s to 75s, which is significantly improved compared to the production efficiency of 6min to 12min / piece in traditional turning, greatly shortening the processing time per piece and significantly reducing time and labor costs.

[0025] 2. This invention uses a single-layer electroplated superhard abrasive as the working layer of the grinding teeth. The abrasive has high bonding strength with the grinding wheel matrix and good wear resistance. By configuring different grinding teeth with the same or different abrasive grit sizes, the wear rate of each tooth tends to be consistent, and the overall service life of the grinding wheel is greatly extended. The average service life of the grinding wheel of this invention can reach 45,000 to 60,000 pieces, which is 90 to 120 times that of the average service life of traditional turning inserts (about 500 pieces). This effectively avoids the waste of time due to frequent machine downtime for tool changes and waiting for inspection, reduces the labor intensity of operators, and further improves the overall processing efficiency.

[0026] 3. This invention uses grinding instead of traditional turning, resulting in higher grinding speeds, thinner cutting layers, and significantly better surface roughness than turning. The surface roughness of the snap ring groove end face after grinding with the grinding wheel of this invention can reach Ra0.32μm~Ra0.4μm, which is far superior to Ra0.8μm~Ra1.2μm of traditional turning. It can reliably meet the stringent requirements of Ra0.8 and other surface quality requirements of precision parts under high-speed conditions in new energy vehicles. Moreover, the grinding texture is finer and more uniform than the turning texture, effectively improving the transmission stability and assembly accuracy of the gear shaft.

[0027] 4. The grinding wheel provided by this invention does not require dressing of the grinding wheel profile during the grinding process. The profile dimensions of the single-layer electroplated superhard abrasive can remain stable for a long time after electroplating and precision dressing, resulting in good dimensional consistency in batch processing. The distance between the teeth of this invention can be stably controlled within ±0.01mm, and the dimensional consistency deviation in batch processing is ≤0.008mm~0.01mm, which is far superior to the ≤0.025mm~0.03mm of traditional turning. No process adjustment or tool compensation is required, which significantly improves the quality stability and pass rate of batch production.

[0028] 5. The grinding wheel manufacturing method provided by this invention achieves precise control over the electroplating of different grit sizes of superhard abrasives on different grinding teeth of the same grinding wheel through a step-by-step masking electroplating process. This ensures that grinding teeth with large grinding allowances or intermittent grinding areas are equipped with coarse abrasives, while the remaining grinding teeth are equipped with fine abrasives, thereby achieving a balanced matching of grinding life for each tooth. This manufacturing method is reliable and controllable, effectively solving the technological challenge of electroplating abrasive grit sizes at different tooth positions on multi-tooth grinding wheels, and providing a feasible industrial solution for the efficient, precise, and low-cost grinding of gear shaft snap ring grooves.

[0029] 6. The grinding wheel and its manufacturing method provided by this invention are highly versatile and applicable to the machining of circlip grooves on gear shafts with different numbers of circlip grooves (1 to 15), different workpiece materials (such as 40Cr, 20CrMnTi, 18CrNiMo7-6, etc.), and different hardness ranges (HRC55 to 64). By simply adjusting the number, shape, and abrasive grit configuration of the grinding teeth on the outer cylindrical surface of the grinding wheel, it can quickly adapt to the machining requirements of different types of gear shafts, and has extremely high industrial application value and market promotion prospects. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 This is a schematic diagram of the first step in the prior art: machining the circlip groove.

[0032] Figure 2 This is a schematic diagram of the second step of machining the circlip groove in the prior art.

[0033] Figure 3 This is a schematic diagram of the structure of the grinding wheel of the present invention.

[0034] Figure 4 This is an enlarged schematic diagram of the abrasive layer portion of the grinding wheel according to the present invention. Detailed Implementation

[0035] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. 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.

[0036] like Figure 3 As shown, this invention provides a grinding wheel for high-efficiency machining of circumferential grooves on gear shafts, comprising a grinding wheel steel substrate 1 and superhard abrasive 2, the superhard abrasive 2 being located on the outer circumferential surface of the grinding wheel steel substrate 1. The outer circumferential surface of the grinding wheel steel substrate 1 is provided with multiple grinding teeth corresponding one-to-one with the circumferential grooves on the gear shaft 3 to be machined. The number of grinding teeth is the same as the number of circumferential grooves on the gear shaft 3 to be machined, generally 1 to 15. Each grinding tooth is electroplated with a single layer of superhard abrasive 2, which can be cubic boron nitride (CBN) abrasive or diamond abrasive, preferably CBN abrasive. During use, all grinding teeth simultaneously participate in grinding the corresponding circumferential grooves in a single feed, and the grinding of all circumferential grooves to be machined is completed in one pass after the grinding process is exited.

[0037] The grinding wheel steel substrate 1 is preferably made of 40Cr or 42CrMo alloy steel, with a tempered hardness of HRC28~35. The end face runout of the grinding wheel steel substrate 1 is ≤0.005mm, and the flatness is ≤0.005mm. The overall dynamic balance grade of the grinding wheel meets the G0.4 standard.

[0038] The grit size of the superhard abrasive on different grinding teeth of the same grinding wheel can be the same or different. For grinding teeth with large grinding allowances and / or intermittent grinding sections 301, the grit size of the superhard abrasive layer electroplated on its surface can be larger, using coarse abrasive 202. The superhard abrasive layer electroplated on the surface of other grinding teeth is fine abrasive 201, such as... Figure 4 As shown. The goal is to ensure that the grinding life of all grinding teeth is similar, and to achieve the optimal overall service life of the grinding wheel.

[0039] The method for manufacturing this grinding wheel includes the following steps:

[0040] (1) Grinding wheel base blank preparation: Grinding wheel base blank is prepared using 40Cr or 42CrMo forgings, with a tempering hardness of HRC28~35, and is required to be free of cracks and sand hole defects.

[0041] (2) Semi-finishing of grinding wheel base: The grinding wheel base blank is rough turned on a lathe, ground to the required thickness on a surface grinder, and ground to the required size on an internal grinding machine, so that the end face runout is ≤0.005mm, the flatness is ≤0.005mm, and the roughness Ra is ≤0.8μm.

[0042] (3) Grinding wheel base precision turning: The mandrel is turned online on the CNC lathe, and the grinding wheel is installed and tightened. The end face runout of the grinding wheel base is required to be ≤0.003mm and the radial runout of the inner hole is required to be ≤0.003mm. The outer circular surface of the grinding wheel base 1 is precision turned to form the base surface of multiple grinding teeth that correspond one-to-one with the snap ring groove on the gear shaft 3 to be processed. Ensure that the distance between the base teeth deviates from the standard size by ≤±0.005mm.

[0043] (4) Electroplating superhard abrasive: A single layer of superhard abrasive 2 is electroplated on each grinding tooth in the outer circular surface area of ​​the grinding wheel substrate 1, and the abrasive embedment rate is controlled within the range of 45% to 60%. If different grinding teeth on the same grinding wheel use superhard abrasives of different grit sizes, a step-by-step masking electroplating process is adopted: First, the grinding teeth with pre-electroplated fine abrasive 201 are masked by electroplating using a masking fixture, and a layer of coarse abrasive 202 is planted on the remaining grinding teeth to start electroplating thickening; Second, when the embedment rate of coarse abrasive 202 reaches the range of 20% to 35%, the masking fixture on the grinding teeth in the first step is removed, and a layer of fine abrasive 201 is planted on the fine abrasive 201 grinding teeth, and the whole process continues to be electroplated thickened; Third, when the embedment rates of fine abrasive 201 and coarse abrasive 202 on all grinding teeth meet the range of 45% to 60%, the electroplating thickening is stopped, and the electroplating process ends.

[0044] (5) Outer cylindrical abrasive layer dressing: Precision dressing of the abrasive layer of each grinding tooth so that the profile and distance of each grinding tooth meet the product size design requirements.

[0045] (6) Dynamic balancing treatment: On a high-precision dynamic balancing machine, by drilling to remove weight, under the condition of grinding wheel speed of 2000R / min, the dynamic imbalance is ≤0.1g, which meets the G0.4 dynamic balance grade standard. If qualified, it is a finished grinding wheel.

[0046] In use, the aforementioned finished grinding wheel is mounted on the spindle of a CNC grinding machine. During a single feed, all grinding teeth on the grinding wheel simultaneously participate in grinding the corresponding snap ring grooves. After the grinding process is completed, all snap ring grooves to be processed are ground in one pass. The grinding process does not require dressing the grinding wheel profile, and the batch processing has high dimensional consistency and stability. The distance between teeth can be stably maintained within ±0.01mm.

[0047] Example 1

[0048] like Figure 3 As shown, a high-efficiency grinding wheel for machining gear shaft snap ring grooves includes a grinding wheel base 1 and a superhard abrasive 2, such as... Figure 4 As shown, the superhard abrasive is located on the outer circumferential surface of the grinding teeth of the grinding wheel matrix 1, and the superhard abrasive is distributed in a single layer.

[0049] The manufacturing method of the grinding wheel for high-efficiency machining of the gear shaft snap ring groove includes the following steps:

[0050] 1) Grinding wheel blank

[0051] The grinding wheel base is made of 40Cr forgings with a tempered hardness of HRC28~35, and is free of cracks and sand holes.

[0052] 2) Semi-finishing of grinding wheel base

[0053] The grinding wheel blank is rough turned on a lathe, ground to the required thickness on a surface grinder, and ground to the required size on an internal grinding machine. The end runout is required to be ≤0.005mm, the flatness is required to be ≤0.005mm, and the roughness Ra is required to be ≤0.8μm.

[0054] 3) Grinding wheel base precision turning

[0055] The CNC lathe performs online turning of the mandrel, and the grinding wheel is installed and tightened. The runout of the grinding wheel base end face is required to be ≤0.003mm, and the radial runout of the inner hole is required to be ≤0.003mm. The base profile of each grinding tooth on the outer circle of the grinding wheel base 1 is precision turned to ensure that the distance between the base teeth deviates from the standard size by ±0.005mm.

[0056] 4) Electroplated superhard abrasive

[0057] Superhard abrasive 2 is electroplated onto all grinding teeth on the outer circumference of the grinding wheel base 1, with the abrasive embedment rate controlled within the range of 45% to 60%. In this embodiment, the number of snap ring grooves on the gear shaft 3 to be processed is 9. Among them, there is a spline discontinuous grinding section 301 in the third snap ring groove. Therefore, a coarser CBN abrasive (grit size B213, i.e., coarse abrasive 202) is selected for this grinding tooth, while a finer CBN abrasive (grit size B151, i.e., fine abrasive 201) is selected for the remaining 8 grinding teeth to ensure that the grinding life of all grinding teeth is similar and the overall service life of the grinding wheel reaches the optimal level.

[0058] The electroplating steps for mixing coarse and fine abrasives are as follows:

[0059] The first step is to use a masking fixture to perform conventional electroplating masking on the eight pre-electroplated fine abrasive 201 grinding teeth. Then, a layer of coarse abrasive 202 is applied to the remaining grinding tooth to thicken the electroplating.

[0060] The second step is to remove the shielding fixtures for the eight grinding teeth when the embedding rate of coarse abrasive 202 reaches 20% to 35%, and then plant a layer of fine abrasive 201 on the eight grinding teeth and continue electroplating to thicken the whole.

[0061] The third step is to stop electroplating when the embedment rate of fine abrasive 201 and coarse abrasive 202 of all grinding teeth of the grinding wheel meets the range of 45% to 60%, and the electroplating process is completed.

[0062] 5) Outer cylindrical abrasive layer dressing

[0063] The abrasive layer of each grinding tooth is precisely dressed to ensure that the profile and distance dimensions of each grinding tooth meet the design requirements of the product drawings.

[0064] 6) Dynamic balancing treatment

[0065] On a high-precision dynamic balancing machine, weight is removed by drilling, ensuring the grinding wheel speed is 2000 R / min and the dynamic imbalance is ≤0.1g. Once qualified, it is considered a finished product.

[0066] Performance Testing: The input gear shaft 3 of the gearbox was machined. The gear shaft workpiece material was 20CrMnTi, with a surface hardening hardness of 58HRC~64HRC. There were 9 snap ring grooves to be machined. The grinding cycle time for the entire gear shaft snap ring grooves was 1 minute. The surface roughness Ra was 0.4μm, which is acceptable. The distance between the teeth was ±0.01mm. The grinding wheel service life was 50,000 pieces, which meets the customer's batch processing requirements. The performance of the grinding wheel prepared in Example 1 of this invention and the traditional turning tool in machining the snap ring grooves of the gearbox gear shaft is compared in Table 1 below.

[0067] Table 1

[0068] Number of cutting tools 1 item 6 items Program feed count 1 time 9 times Processing cycle time 1 min / piece 10min / piece Surface roughness Ra0.48um R1.0um Dimensional accuracy ±0.01mm ±0.01mm Batch processing dimensional consistency deviation ≤0.01mm ≤0.03mm Process trimming / adjustment methods No modifications or adjustments are required during the process. The process adjusts tool compensation based on the test data. Average service life 50,000 pieces 500 pieces

[0069] Example 2

[0070] like Figure 3 As shown, a high-efficiency grinding wheel for machining gear shaft snap ring grooves includes a grinding wheel base 1 and a superhard abrasive 2, such as... Figure 4As shown, the superhard abrasive 2 is located on the outer circumferential surface of the grinding teeth of the grinding wheel matrix 1, and the superhard abrasive 2 is distributed in a single layer. The difference between this embodiment and embodiment 1 is that the gear shaft 3 to be processed is the intermediate shaft of a certain type of commercial vehicle gearbox, the number of snap ring grooves is 5, the material of the gear shaft workpiece is 40Cr, the surface quenching hardness is HRC55~60, the width of the snap ring groove is 4mm, and the groove depth is 2.5mm.

[0071] The manufacturing method of the grinding wheel for high-efficiency machining of the gear shaft snap ring groove includes the following steps:

[0072] 1) Grinding wheel blank

[0073] The grinding wheel base is made of 40Cr forgings with a tempered hardness of HRC28~32, and is free of cracks and sand holes.

[0074] 2) Semi-finishing of grinding wheel base

[0075] The grinding wheel blank is rough turned on a lathe, ground to the required thickness on a surface grinder, and ground to the required size on an internal grinding machine. The end runout is required to be ≤0.005mm, the flatness is required to be ≤0.005mm, and the roughness Ra is required to be ≤0.8μm.

[0076] 3) Grinding wheel base precision turning

[0077] The CNC lathe performs online turning of the mandrel, and the grinding wheel is installed and tightened. The runout of the grinding wheel base end face is required to be ≤0.003mm, and the radial runout of the inner hole is required to be ≤0.003mm. The base profile of each grinding tooth on the outer circle of the grinding wheel base 1 is precision turned to ensure that the distance between the base teeth deviates from the standard size by ±0.005mm.

[0078] 4) Electroplated superhard abrasive

[0079] Superhard abrasive 2 is electroplated onto all grinding teeth on the outer circumference of the grinding wheel substrate 1, with the abrasive embedment rate controlled within the range of 45% to 60%. In this embodiment, all five grinding teeth use CBN abrasive with the same grit size, B181. This is because the grinding allowance of the five snap ring grooves in this embodiment is uniform, there are no discontinuous grinding sections, and the wear rate of each tooth is consistent, eliminating the need for a mixed grit size scheme.

[0080] The specific steps of electroplating are as follows:

[0081] The first step is to perform pretreatment processes such as degreasing and hydrophilic treatment on all five grinding tooth areas;

[0082] The second step is to apply a layer of B126 CBN abrasive to all the grinding teeth on the outer circle of the grinding wheel base 1;

[0083] The third step is to begin electroplating to thicken the abrasive layer until the abrasive embedment rate of all grinding teeth meets the range of 50% to 60%. Then, the electroplating thickening process is stopped, and the electroplating process is completed.

[0084] 5) Outer cylindrical abrasive layer dressing

[0085] The abrasive layer of each grinding tooth is precisely dressed to ensure that the profile and distance dimensions of each grinding tooth meet the design requirements of the product drawings.

[0086] 6) Dynamic balancing treatment

[0087] On a high-precision dynamic balancing machine, weight is removed by drilling, ensuring that the grinding wheel speed is 3000 R / min and the dynamic imbalance is ≤0.1g. Once qualified, it is considered a finished product.

[0088] Performance Testing: The intermediate shaft of a commercial vehicle gearbox was machined. The workpiece was made of 40Cr steel with a surface hardening hardness of HRC55-60. Five circlip grooves were to be machined. The grinding cycle for the entire gear shaft circlip grooves was 40 seconds. The surface roughness Ra was 0.32μm, which is acceptable. The tooth-to-tooth distance was ±0.008mm. The grinding wheel life was 60,000 pieces, meeting the customer's batch processing requirements.

[0089] The machining effect of the grinding wheel prepared in Example 2 of this invention is compared with that of a traditional lathe tool, as shown in Table 2.

[0090] Table 2 Number of cutting tools 1 item 3 items Program feed count 1 time 5 times Processing cycle time 40s / piece 6 min / piece Surface roughness Ra0.4μm Ra0.8μm Dimensional accuracy ±0.008mm ±0.01mm Batch processing dimensional consistency deviation ≤0.008mm ≤0.025mm Process trimming / adjustment methods No modifications or adjustments are required during the process. The process adjusts tool compensation based on the test data. Average service life 60,000 pieces 500 pieces

[0091] Example 3

[0092] A high-efficiency grinding wheel for machining circlip grooves on gear shafts includes a grinding wheel base 1 and a superhard abrasive 2. The difference between this embodiment and Embodiment 1 is that the gear shaft 3 to be machined is the output shaft of a passenger vehicle gearbox, with 12 circlip grooves. The gear shaft workpiece material is 18CrNiMo7-6, with a surface carburized and quenched hardness of HRC58-62. The circlip groove width is 3.2 mm and the groove depth is 2.0 mm.

[0093] The manufacturing method of the grinding wheel for high-efficiency machining of the gear shaft snap ring groove includes the following steps:

[0094] 1) Grinding wheel blank

[0095] The grinding wheel base is made of 42CrMo forgings, with a tempered hardness of HRC30-35, and is free of cracks and sand holes.

[0096] 2) Semi-finishing of grinding wheel base

[0097] The grinding wheel blank is rough turned on a lathe, ground to the required thickness on a surface grinder, and ground to the required size on an internal grinding machine. The end runout is required to be ≤0.005mm, the flatness is required to be ≤0.005mm, and the roughness Ra is required to be ≤0.8μm.

[0098] 3) Grinding wheel base precision turning

[0099] The CNC lathe performs online turning of the mandrel, and the grinding wheel is installed and tightened. The runout of the grinding wheel base end face is required to be ≤0.003mm, and the radial runout of the inner hole is required to be ≤0.003mm. The base profile of each grinding tooth on the outer circle of the grinding wheel base 1 is precision turned to ensure that the distance between the base teeth deviates from the standard size by ±0.005mm.

[0100] 4) Electroplated superhard abrasive

[0101] Superhard abrasive 2 is electroplated onto all grinding teeth on the outer circumference of the grinding wheel substrate 1, with the abrasive embedment rate controlled within the range of 45% to 60%. In this embodiment, because there are spline discontinuous grinding areas at the corresponding positions of the 3rd and 7th snap ring grooves, the impact during grinding is greater, and the wear rate is higher than that of other teeth. Therefore, a coarser CBN abrasive (grit size B91, i.e., coarse abrasive 202) is electroplated onto the surface of these two grinding teeth, while a finer CBN abrasive (grit size B64, i.e., fine abrasive 201) is electroplated onto the surface of the remaining 10 grinding teeth. This ensures that the grinding life of all grinding teeth is similar, and the overall service life of the grinding wheel reaches its optimal level.

[0102] The electroplating steps for mixing coarse and fine abrasives are as follows:

[0103] The first step is to use a masking fixture to perform conventional electroplating masking on the grinding teeth of 10 pre-electroplated fine abrasive 201. Then, a layer of coarse abrasive 202 (B91) is applied to the grinding teeth of the remaining two teeth (corresponding to the 3rd and 7th snap ring slots) to thicken the electroplating.

[0104] The second step is to remove the shielding fixtures for the 10 grinding teeth areas when the embedding rate of coarse abrasive 202 reaches 25% to 35%, and then plant a layer of fine abrasive 201 (B64) on the 10 grinding teeth, and continue electroplating to thicken the whole.

[0105] The third step is to stop electroplating when the embedment rate of fine abrasive 201 and coarse abrasive 202 of all grinding teeth of the grinding wheel meets the range of 45% to 55%, and the electroplating process is completed.

[0106] 5) Outer cylindrical abrasive layer dressing

[0107] The abrasive layer of each grinding tooth is precisely dressed to ensure that the profile and distance dimensions of each grinding tooth meet the design requirements of the product drawings.

[0108] 6) Dynamic balancing treatment

[0109] On a high-precision dynamic balancing machine, weight is removed by drilling, ensuring the grinding wheel speed is 2500 R / min and the dynamic imbalance is ≤0.08g. Once qualified, it is considered a finished product.

[0110] Performance Testing: The output shaft of a passenger vehicle gearbox was machined. The workpiece material was 18CrNiMo7-6, with a surface carburized and quenched hardness of HRC58-62. There were 12 circlip grooves to be machined (two of which involved intermittent spline grinding). The grinding cycle time for the entire gear shaft circlip grooves was 75 seconds. The surface roughness Ra was 0.35μm, which is acceptable. The tooth-to-tooth distance was ±0.01mm, and the grinding wheel life was 45,000 pieces, meeting the customer's batch processing requirements.

[0111] The machining effect of the grinding wheel prepared in Example 3 of this invention is compared with that of a traditional lathe tool, as shown in Table 3.

[0112] Table 3

[0113] Number of cutting tools 1 item 8 items Program feed count 1 time 12 times Processing cycle time 75s / piece 12min / piece Surface roughness Ra0.35μm Ra1.2μm Dimensional accuracy ±0.01mm ±0.015mm Batch processing dimensional consistency deviation ≤0.01mm ≤0.03mm Process trimming / adjustment methods No modifications or adjustments are required during the process. The process adjusts tool compensation based on the test data. Average service life 50,000 pieces 500 pieces

[0114] In summary, the grinding wheel and its manufacturing method for high-efficiency machining of gear shaft circlip grooves provided by this invention achieve one-time forming grinding of all circlip grooves by integrating multiple grinding teeth onto the same grinding wheel base, increasing production efficiency by more than 10 times. Through a single-layer electroplated superhard abrasive and a combination of coarse and fine grit designs, the average service life of the grinding wheel reaches more than 100 times that of traditional lathe cutting tools. Through precision dressing and high-precision dynamic balancing, batch machining dimensional consistency can be stably achieved to ±0.01mm, and surface roughness can easily reach within Ra0.4μm. This invention effectively solves the long-standing technical problems plaguing the industry, such as slow machining efficiency, insufficient surface quality, and short tool life of circlip grooves in gear shafts of new energy vehicle transmissions, and has extremely high industrial application value and market promotion prospects.

[0115] It should be noted that the parameters such as end face runout, flatness, roughness, precision turning accuracy, and tooth pitch deviation of the grinding wheel base mentioned above are basic accuracy ranges set based on the working conditions of multiple teeth participating in grinding simultaneously. They do not change with the number of snap ring grooves, material, and abrasive configuration of the gear shaft to be processed, and are applicable to all embodiments described in this invention.

[0116] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that any modifications to the technical solutions described in the foregoing embodiments, or equivalent substitutions of some or all of the technical features thereof, within the spirit and principles of the present invention, 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, and should all be included within the protection scope of the present invention.

Claims

1. A grinding wheel for machining the circlip groove of a gear shaft, characterized in that, It includes a grinding wheel steel substrate (1), the outer circular surface of which is provided with a plurality of grinding teeth corresponding one-to-one with the snap ring groove of the gear shaft (3) to be processed, and each grinding tooth is electroplated with a single layer of superhard abrasive (2), and the number of grinding teeth is the same as the number of snap ring grooves on the gear shaft to be processed.

2. The grinding wheel for machining the gear shaft snap ring groove according to claim 1, characterized in that, The particle size of the superhard abrasive (2) on different grinding teeth of the same grinding wheel is the same.

3. The grinding wheel for machining the gear shaft snap ring groove according to claim 1, characterized in that, The particle size of the superhard abrasive (2) on the same grinding wheel with different grinding teeth is different.

4. The grinding wheel for machining the gear shaft snap ring groove according to claim 3, characterized in that, For the grinding teeth that correspond to a large grinding allowance and / or have intermittent grinding sections (301), the superhard abrasive (2) electroplated on their surface is a coarse abrasive (202); the superhard abrasive (2) electroplated on the surface of other grinding teeth is a fine abrasive (201).

5. The grinding wheel for machining the circlip groove of a gear shaft according to any one of claims 1 to 4, characterized in that, The grinding wheel steel substrate (1) is made of 40Cr or 42CrMo and has a tempering hardness of HRC28~35.

6. The grinding wheel for machining the circlip groove of a gear shaft according to any one of claims 1 to 4, characterized in that, The end face runout of the grinding wheel steel substrate (1) is ≤0.005mm, and the flatness is ≤0.005mm.

7. A method for manufacturing a grinding wheel for high-efficiency machining of gear shaft snap ring grooves, characterized in that, Includes the following steps: (1) Grinding wheel base blank preparation: Grinding wheel base blanks are prepared using 40Cr or 42CrMo forgings, and the hardness is HRC28~35 after quenching and tempering. (2) Semi-finishing of grinding wheel base: The grinding wheel base blank is rough turned on a lathe, the thickness is ground to the required size on a surface grinder, and the inner hole is ground to the required size on an internal grinding machine, so that the end face runout is ≤0.005mm, the flatness is ≤0.005mm, and the roughness Ra is ≤0.8μm; (3) Grinding wheel base precision turning: The mandrel is turned online on the CNC lathe, the grinding wheel is installed and pressed, and the outer cylindrical surface of the grinding wheel base (1) is precision turned to form a base surface of multiple grinding teeth that correspond one-to-one with the snap ring groove of the gear shaft (3) to be processed; (4) Electroplating superhard abrasive: A single layer of superhard abrasive (2) is electroplated on each grinding tooth in the outer circular surface area of ​​the grinding wheel substrate (1), and the abrasive embedment rate is controlled in the range of 45% to 60%. (5) Outer cylindrical abrasive layer dressing: Precision dressing of the abrasive layer of each grinding tooth so that the profile and distance of each grinding tooth meet the product size design requirements; (6) Dynamic balancing: The grinding wheel is dynamically balanced until it meets the requirements.

8. The method for manufacturing a grinding wheel for machining a gear shaft snap ring groove according to claim 7, characterized in that, In step (3), after precision turning, the runout of the grinding wheel base end face is ≤0.003mm, the radial runout of the inner hole is ≤0.003mm, and the distance between the base teeth deviates from the standard size by ≤±0.005mm.

9. The method for manufacturing a grinding wheel for machining a gear shaft snap ring groove according to claim 7, characterized in that, In step (4), the electroplating of superhard abrasives of different particle sizes adopts a step-by-step masking electroplating process, specifically including: The first step is to use a masking fixture to electroplat and mask the grinding teeth with pre-set fine abrasive (201), and then apply a layer of coarse abrasive (202) to the grinding teeth with pre-set coarse abrasive (202) to thicken the grinding teeth by electroplating. The second step is to remove the shielding fixture mentioned in the first step when the embedment rate of coarse abrasive (202) reaches 20% to 35%, and then plant a layer of fine abrasive (201) on the grinding teeth of the pre-set fine abrasive (201), and continue to electroplate the whole to thicken it. The third step is to stop electroplating when the embedment rate of fine abrasive (201) and coarse abrasive (202) of all grinding teeth meets the range of 45% to 60%.

10. A grinding method for a gear shaft snap ring groove, characterized in that, Using any one of the grinding wheels according to claims 1 to 4, all grinding teeth on the grinding wheel participate in grinding the corresponding circlip grooves simultaneously during one feed, and after the grinding process is exited, the grinding process of all circlip grooves to be processed is completed in one go.

Images