Crankshaft chain wheel fillet grinding method, device and equipment and storage medium

Abstract

The invention provides a crankshaft chain wheel fillet grinding method, device and equipment and a storage medium, and the method comprises the steps that coordinates of a plurality of interpolation points used for approaching the contour of a fillet are calculated according to geometric parameters of the fillet to be machined; according to the coordinates of the interpolation points, a numerical control program for controlling the grinding wheel to sequentially pass through the interpolation points in an incremental movement mode is generated; and the numerical control program is executed, the grinding wheel is controlled to conduct linear interpolation grinding along a track formed by the interpolation points, and therefore the fillet is machined. By the adoption of the method, the machining adaptability, the track control accuracy, the machining accuracy and the consistency can be improved.

Description

Technical Field

[0001] This application relates to the field of automated machining, and more specifically, to a method, apparatus, equipment, and storage medium for grinding the fillet radius of a crankshaft sprocket. Background Technology

[0002] In the engine power transmission system, the crankshaft sprocket is a key transmission component. The machining quality of the fillet at the root of its journal directly determines the fatigue strength and service life of the crankshaft. It is necessary to strictly control the fillet contour accuracy and surface quality to ensure the overall reliability of the engine.

[0003] Currently, the industry commonly uses the forming wheel grinding process to process crankshaft sprocket fillets. This process uses a customized integrated forming wheel that perfectly matches the theoretical contour of the target fillet, and employs either plunge grinding or longitudinal grinding to complete the fillet grinding in one go.

[0004] The core flaw of this process is the extremely poor versatility of the grinding wheels. Different shaped grinding wheels need to be customized for different radius specifications of fillets. When changing models, complex dressing operations are required for the new grinding wheels. This not only significantly increases the cost of grinding wheel procurement and maintenance, but also severely slows down the production cycle due to the excessive dressing time, making it difficult to adapt to the needs of multi-variety and batch production. Summary of the Invention

[0005] In view of this, the purpose of this application is to provide a method, apparatus, equipment and storage medium for grinding the fillet radius of a crankshaft sprocket, which can improve the adaptability of processing, the accuracy of trajectory control, and the processing precision and consistency.

[0006] In a first aspect, embodiments of this application provide a method for grinding the fillet radius of a crankshaft sprocket, the method comprising: Based on the geometric parameters of the fillet to be processed, calculate the coordinates of multiple interpolation points used to approximate the fillet profile; Based on the coordinates of the interpolation points, a CNC program is generated to control the grinding wheel to move incrementally through each of the interpolation points in sequence. The CNC program is executed to control the grinding wheel to perform linear interpolation grinding along the trajectory formed by the interpolation points, thereby machining the fillet.

[0007] Optionally, the step of calculating the coordinates of multiple interpolation points for approximating the fillet contour based on the geometric parameters of the fillet to be processed includes: Calculate the fillet arc length L based on the fillet radius R and the preset central angle; Calculate the number n of equal arc length division points based on the arc length L and the set single-point arc length increment ΔL; Establish a rectangular coordinate system with the center of the crankshaft sprocket journal as the origin, and calculate the coordinates of each point by selecting the corresponding parametric equation based on whether the fillet is concave or convex.

[0008] Optionally, when machining concave fillets, the parametric equation is: ; ; in, and The first The radial and axial coordinates of each point in the Cartesian coordinate system The journal radius of the crankshaft sprocket is [missing information]. For the first The central angles corresponding to the dividing points.

[0009] Optionally, when machining convex fillets, the parametric equation is: ; ; in, and The first The radial and axial coordinates of each point in the Cartesian coordinate system The journal radius of the crankshaft sprocket is [missing information]. For the first The central angles corresponding to the dividing points.

[0010] Optionally, the step of generating a CNC program to control the grinding wheel to sequentially pass through each of the interpolation points in an incremental manner, based on the coordinates of the interpolation points, includes: Calculate the radial and axial movement increments of the grinding wheel based on the coordinates of adjacent interpolation points; The incremental movement is converted into incremental motion commands that the CNC system can recognize and integrated into a complete CNC machining program.

[0011] Optionally, executing the CNC program to control the grinding wheel to perform linear interpolation grinding along the trajectory formed by the interpolation points, thereby machining the fillet, includes: Position the grinding wheel at the grinding start point; Switch the CNC system to incremental programming mode; The incremental motion command is executed to control the grinding wheel to pass through each interpolation point sequentially at a set feed rate for grinding. After grinding is complete, switch to absolute programming mode and retract the grinding wheel to a safe position.

[0012] Optionally, the value range of the single-point arc length increment ΔL is 0.005mm to 0.015mm, and the grinding wheel is a narrow grinding wheel with a width of 8mm to 12mm, and its own corner radius is less than or equal to the minimum corner radius to be processed.

[0013] Secondly, embodiments of this application provide a crankshaft sprocket fillet grinding device, the device comprising: The coordinate calculation module is used to calculate the coordinates of multiple interpolation points to approximate the contour of the fillet based on the geometric parameters of the fillet to be processed. The program generation module is used to generate a CNC program that controls the grinding wheel to move incrementally through each of the interpolation points according to the coordinates of the interpolation points; The program execution module is used to execute the CNC program and control the grinding wheel to perform linear interpolation grinding along the trajectory formed by the interpolation points, thereby machining the fillet.

[0014] Optionally, the step of calculating the coordinates of multiple interpolation points for approximating the fillet contour based on the geometric parameters of the fillet to be processed includes: Calculate the fillet arc length L based on the fillet radius R and the preset central angle; Calculate the number n of equal arc length division points based on the arc length L and the set single-point arc length increment ΔL; Establish a rectangular coordinate system with the center of the crankshaft sprocket journal as the origin, and calculate the coordinates of each point by selecting the corresponding parametric equation based on whether the fillet is concave or convex.

[0015] Optionally, when machining concave fillets, the parametric equation is: ; ; in, and The first The radial and axial coordinates of each point in the Cartesian coordinate system The journal radius of the crankshaft sprocket is [missing information]. For the first The central angles corresponding to the dividing points.

[0016] Optionally, when machining convex fillets, the parametric equation is: ; ; in, and The first The radial and axial coordinates of each point in the Cartesian coordinate system The journal radius of the crankshaft sprocket is [missing information]. For the first The central angles corresponding to the dividing points.

[0017] Optionally, the step of generating a CNC program to control the grinding wheel to sequentially pass through each of the interpolation points in an incremental manner, based on the coordinates of the interpolation points, includes: Calculate the radial and axial movement increments of the grinding wheel based on the coordinates of adjacent interpolation points; The incremental movement is converted into incremental motion commands that the CNC system can recognize and integrated into a complete CNC machining program.

[0018] Optionally, executing the CNC program to control the grinding wheel to perform linear interpolation grinding along the trajectory formed by the interpolation points, thereby machining the fillet, includes: Position the grinding wheel at the grinding start point; Switch the CNC system to incremental programming mode; The incremental motion command is executed to control the grinding wheel to pass through each interpolation point sequentially at a set feed rate for grinding. After grinding is complete, switch to absolute programming mode and retract the grinding wheel to a safe position.

[0019] Optionally, the value range of the single-point arc length increment ΔL is 0.005mm to 0.015mm, and the grinding wheel is a narrow grinding wheel with a width of 8mm to 12mm, and its own corner radius is less than or equal to the minimum corner radius to be processed.

[0020] Thirdly, embodiments of this application provide a computer device, including: a processor, a memory, and a bus. The memory stores machine-readable instructions executable by the processor. When the computer device is running, the processor communicates with the memory via the bus. When the machine-readable instructions are executed by the processor, the steps of the crankshaft sprocket fillet grinding method described in any of the optional embodiments of the first aspect are performed.

[0021] Fourthly, embodiments of this application provide a computer-readable storage medium storing a computer program that, when executed by a processor, performs the steps of the crankshaft sprocket fillet grinding method described in any of the optional embodiments of the first aspect.

[0022] The technical solution provided in this application includes, but is not limited to, the following beneficial effects: Based on the geometric parameters of the fillet to be processed, the coordinates of multiple interpolation points used to approximate the fillet contour are calculated. This step can accurately adapt to fillets of different specifications. By deriving the coordinates of the interpolation points through geometric parameters, it can flexibly meet the needs of fillet processing of different radii and different types (concave / convex) without relying on processing tools with fixed contours, thus ensuring the adaptability and basic accuracy of the processing from the source.

[0023] Based on the coordinates of the interpolation points, a CNC program is generated to control the grinding wheel to move incrementally through each interpolation point. This step precisely defines the grinding wheel's trajectory through incremental movement commands. Each incremental movement is precisely calculated based on the coordinates of the interpolation points, effectively avoiding trajectory deviation and ensuring the accuracy of the grinding wheel's movement. At the same time, the CNC program can directly adapt to different interpolation point data. When changing models, only the coordinate parameters need to be updated to generate a new program, simplifying the model changeover process.

[0024] The CNC program is executed to control the grinding wheel to perform linear interpolation grinding along the trajectory formed by the interpolation points, thereby machining the fillet. This step approximates the fillet contour through linear interpolation. The continuous grinding of multiple short straight lines can restore the target fillet shape to the greatest extent, significantly improving the fillet contour accuracy and surface quality. Moreover, the entire machining process is automatically controlled by the program, avoiding human operation errors and ensuring the consistency of precision of batch-processed products.

[0025] The three steps of this application are progressively advanced, from the adaptability of coordinate calculation and the accuracy of program generation to the high precision and consistency of grinding execution, forming a complete technical closed loop. Its core beneficial effects are mainly reflected in strong processing adaptability, precise trajectory control, and high processing accuracy and consistency, effectively solving the pain points of traditional processing methods in terms of multi-specification adaptation and precision control, and providing an efficient and reliable technical path for fillet machining.

[0026] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0027] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 A flowchart of a crankshaft sprocket fillet grinding method provided in Embodiment 1 of this application is shown; Figure 2 This paper shows a schematic diagram of the distribution of fillet radius of a crankshaft sprocket according to Embodiment 1 of this application; Figure 3 A schematic diagram of a CBN grinding wheel provided in Embodiment 1 of this application is shown; Figure 4 A flowchart of an interpolation point coordinate calculation method provided in Embodiment 1 of this application is shown; Figure 5A flowchart of a numerical control program generation method provided in Embodiment 1 of this application is shown; Figure 6 A flowchart of a numerical control program execution method provided in Embodiment 1 of this application is shown; Figure 7 This paper shows a schematic diagram of a crankshaft sprocket fillet grinding device provided in Embodiment 2 of this application; Figure 8 A schematic diagram of the structure of a computer device provided in Embodiment 3 of this application is shown. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely represents selected embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0030] Example 1 To facilitate understanding of this application, the following is combined with... Figure 1 The flowchart illustrating a crankshaft sprocket fillet grinding method provided in Embodiment 1 of this application will be used to describe Embodiment 1 of this application in detail.

[0031] See Figure 1 As shown, Figure 1 A flowchart of a crankshaft sprocket fillet grinding method according to Embodiment 1 of this application is shown, wherein the method includes steps S101 to S103: S101: Calculate the coordinates of multiple interpolation points used to approximate the contour of the fillet based on the geometric parameters of the fillet to be processed.

[0032] Specifically, the geometric parameters of the fillets to be machined include: the crankshaft has three sprockets, the nominal diameter of the crankshaft sprocket shaft is 40mm (corresponding to the nominal radius of the journal r=20mm), the actual measured dimensional tolerance of the journal after machining is ≤±0.003mm, the concave fillet radii at the root of each sprocket shaft diameter are R1=1.3mm, R2=5mm, and R3=8mm respectively, the convex fillet radius on the top of the sprocket tooth is R4=2mm, and the preset central angle α=90° (which conforms to the conventional right-angle transition design at the root of the crankshaft shaft diameter, and the measured value of 39.998mm is within the acceptable range for the nominal diameter of 40mm).

[0033] See Figure 2 As shown, Figure 2 The diagram shows the distribution of the fillets of a crankshaft sprocket provided in Embodiment 1 of this application. The concave fillets at the root of the crankshaft sprocket shaft diameter at three locations are R1=1.3mm (6 locations), R2=5mm, and R3=8mm, respectively, and the convex fillets on the top of the sprocket teeth are R4=2mm (6 locations), which visually demonstrates the distribution of fillets of various specifications.

[0034] The calculation first uses the arc length formula L=πR / 2 (simplified because α=90°) to calculate the arc length of each fillet. For example, the arc length of R5 concave fillet is L=π×5 / 2≈7.854mm, and the arc length of R2 convex fillet is L=π×2 / 2≈3.1416mm. Then, the number of division points is determined according to the formula n=L / ΔL (ΔL is the single-point arc length increment, which takes a value of 0.005mm-0.015mm. In this application, 0.01mm is preferred to meet IT6 level accuracy). For example, for R5 concave fillet, n=7.854 / 0.01=786, and for R2 convex fillet, n=315.

[0035] Finally, by combining the parametric equations corresponding to concave / convex fillets, including the center of the concave fillet O1(r+R,0) and the center of the convex fillet O2(rR,0), the coordinates of the interpolation point covering the entire arc length of the fillet are calculated, thus solving the problem that traditional forming grinding wheels cannot adapt to fillets with multiple radii.

[0036] S102: Based on the coordinates of the interpolation points, generate a CNC program to control the grinding wheel to move incrementally through each interpolation point in sequence.

[0037] Specifically, the movement increment is first calculated by the difference in coordinates between adjacent interpolation points, i.e., radial increment ΔXi = Xi - Xi-1 and axial increment ΔZi = Zi - Zi-1 (Xi and Zi are the coordinates of the i-th sub-point, and Xi-1 and Zi-1 are the coordinates of the (i-1)-th sub-point). For example, for the R5 concave fillet, the first sub-point ΔX1 ≈ 0.0012mm and ΔZ1 ≈ 0.0100mm, and the 786th sub-point ΔX786 ≈ 0.0059mm and ΔZ786 ≈ 0.0011mm.

[0038] Then, use the Fanuc 18i CNC system G-code format to write the program. The program must include initialization instructions (G21 metric units, G90 absolute programming, G99 feed rate in minutes, G40 cancel tool tip radius compensation, G49 cancel tool length compensation) and grinding wheel spindle control instructions (concave fillet grinding S=3800r / min, convex fillet grinding S=1500r / min, both in conjunction with M03 spindle forward rotation).

[0039] It also needs to include rapid positioning instructions (such as positioning the R5 concave fillet to the X50.0Z-10.0 safe position), incremental interpolation instructions (after switching to incremental mode with G91, execute multiple G01 XΔXi ZΔZi segments at a feed speed of F=80mm / min), and program end instructions (M05 spindle stop, M30 program reset) to form a complete CNC program (such as R5 concave fillet program number O0001, R2 convex fillet program number O0002). Unlike traditional technologies, it does not require customized programs that rely on special forming grinding wheels, thus reducing the complexity of changeover.

[0040] S103: Execute the CNC program to control the grinding wheel to perform linear interpolation grinding along the trajectory formed by the interpolation points, thereby machining the fillet.

[0041] Specifically, before execution, the grinding wheel installation and adjustment (installing the narrow grinding wheel on the spindle of the CNC grinding machine, ensuring that the grinding wheel axis is parallel to the crankshaft axis, with a runout of ≤0.002mm) and crankshaft clamping (positioning with double centers and chuck, ensuring that the coaxiality between the crankshaft axis and the grinding machine spindle axis is ≤0.003mm).

[0042] See Figure 3 As shown, Figure 3 A schematic diagram of a CBN grinding wheel provided in Embodiment 1 of this application is shown. The grinding wheel is a narrow grinding wheel made of CBN cubic boron nitride material, with a fillet radius of R1.3mm (equal to the minimum fillet radius to be processed), a width of 10mm (range 8-12mm), and a diameter of 450mm. After installation, the grinding wheel axis needs to be adjusted to be parallel to the crankshaft axis, and the runout is tested to be ≤0.002mm.

[0043] The crankshaft must also be clamped: a combination of double ejector pins and a chuck is used for positioning to ensure that the coaxiality between the crankshaft axis and the grinding machine spindle axis is ≤0.003mm, thus avoiding machining errors caused by clamping deviations.

[0044] During execution, the CNC system approximates the arc contour through multiple short straight lines with an interpolation error of ≤0.001mm, and sequentially completes the machining of the concave fillets (R1.3, R5, R8) and convex fillets (R2) of the three sprockets.

[0045] After machining, precision testing is required: a roundness meter is used to measure the fillet radius (e.g., R5 concave fillet is measured to be 4.997mm, R2 convex fillet is measured to be 1.998mm, with tolerances ≤ ±0.005mm), and a micrometer is used to measure the journal dimension (e.g., journal is measured to be 39.998mm, with tolerances ≤ ±0.003mm). The surface roughness of the sprocket tooth tip side reaches Ra=0.4μm. At the same time, since multiple CBN forming grinding wheels are not required (traditional CBN forming grinding wheels have high unit prices), the grinding wheel cost is significantly reduced, solving the problems of poor precision consistency and high cost of traditional technology.

[0046] In an optional implementation, see Figure 4 As shown, Figure 4 The flowchart of an interpolation point coordinate calculation method provided in Embodiment 1 of this application is shown. The step of calculating the coordinates of multiple interpolation points used to approximate the contour of the fillet based on the geometric parameters of the fillet to be processed includes steps S401-S403: S401: Calculate the arc length L of the fillet based on the fillet radius R and the preset central angle.

[0047] Specifically, the preset central angle α = 90° (i.e. π / 2 radians) is used. The root of the conventional crankshaft diameter has a right-angle transition, and both concave and convex fillets conform to this structural characteristic.

[0048] The arc length calculation formula is derived based on the geometric relationship between the central angle and the arc length. Since α = 90°, the original formula L = πRα / 180 is simplified to L = πR / 2, which can be directly substituted into the radius of each fillet for calculation. For example, the arc length of a concave fillet of R1.3 is L = π × 1.3 / 2 ≈ 2.042 mm, and the arc length of a concave fillet of R8 is L = π × 8 / 2 ≈ 12.566 mm. This provides a basis for subsequent point-by-point calculations and avoids the problem that traditional techniques cannot adapt to different radius arc lengths due to the fixed profile of the grinding wheel.

[0049] S402: Calculate the number n of equal arc length division points based on the arc length L and the set single-point arc length increment ΔL.

[0050] Specifically, the value range of the single-point arc length increment ΔL is 0.005mm-0.015mm. This application preferably uses ΔL=0.01mm. This value can meet the IT6 grade accuracy requirement of crankshaft fillet and ensure that the fluctuation of fillet size after machining is controlled within the tolerance range.

[0051] The number of dividing points, n, is calculated using the rounding-up formula n = L / ΔL. The "rounding-up" design ensures that the dividing points completely cover the entire fillet arc length, avoiding outline loss due to insufficient dividing points. For example, for a concave fillet of R1.3, L ≈ 2.042mm, n = 2.042 / 0.01 =205; R8 concave fillet L≈12.566mm, n= 12.566 / 0.01 =1257, the multi-point design is the key to ensuring grinding accuracy, which is different from the traditional form grinding wheel that relies on the accuracy of the grinding wheel profile.

[0052] S403: Establish a rectangular coordinate system with the center of the crankshaft sprocket journal as the origin, and calculate the coordinates of each point by selecting the corresponding parametric equation according to whether the fillet is concave or convex.

[0053] Specifically, the coordinate system is established by determining the crankshaft journal center O(0,0) using an edge finder. The X-axis is defined as the crankshaft radial direction (positive in the direction away from the center) and the Z-axis is defined as the crankshaft axial direction (positive in the direction of sprocket distribution). This coordinate system is designed to fit the actual structure of the crankshaft sprockets, making it easy to accurately locate the fillet positions.

[0054] The concave fillet uses a parametric equation with O1(r+R,0) as the center (r=20mm is the journal radius). For example, the center of the R5 concave fillet is O1(20+5,0)=(25,0). The central angle θi of the dividing point gradually increases from -90° to 0°, with a step size Δθ=90° / (n-1) (e.g., when n=786, Δθ≈0.1146°). The coordinates of the i-th dividing point are Xi=(r+R)cosθi and Zi=(r+R)sinθi.

[0055] The convex fillet uses a parametric equation with O2(rR,0) as the center. For example, the center of the R2 convex fillet is O2(20-2,0)=(18,0). The central angle φi of the dividing point gradually increases from 0° to 90°, with a step size Δφ=90° / (n-1) (e.g., when n=315, Δφ≈0.2866°). The coordinates of the i-th dividing point are Xi=(rR)cosφi and Zi=(rR)sinφi.

[0056] In actual calculations, the starting central angle needs to be adjusted according to the crankshaft structure. For example, the starting point of the R5 concave fillet is the intersection of the outer circle of the journal (X=20mm) and the fillet (Z=-5mm), corresponding to θ=arccos(20 / 25)=36.87°. Therefore, the central angle needs to be adjusted from -36.87° to 53.13° to ensure that the coordinate calculation fits the actual machining requirements.

[0057] In an optional implementation, when machining concave fillets, the parametric equation is: ; ; Where Xi and Zi are the radial and axial coordinates of the i-th division point in the rectangular coordinate system, respectively, r is the journal radius of the crankshaft sprocket, and θi is the central angle corresponding to the i-th division point.

[0058] Specifically, r is fixed at 20mm (corresponding to a crankshaft sprocket shaft diameter of 40mm, which is a specific parameter for the machining object), and R is the concave fillet radius, which can be 1.3mm, 5mm, or 8mm respectively, to adapt to the different concave fillet requirements of the three sprockets on the crankshaft.

[0059] The range of θi needs to be adjusted according to the actual position of the fillet, and is not fixed from -90° to 0°. For example, when machining a concave fillet of R1.3, since the fillet is located in a narrow space at the root of the shaft diameter, the starting point is the intersection of the outer circle of the journal (X=20mm) and the fillet. The corresponding initial value of θi needs to be calculated through geometric relationships (such as θ=arccos(20 / (20+1.3))≈arccos(0.9389)≈20.5°) to ensure that the point trajectory completely covers the concave fillet contour.

[0060] Taking R8 concave fillet as an example, the center O1(20+8,0)=(28,0), n=1257, θi gradually increases from -90° to 0°, and the step size Δθ=90° / (1257-1)≈0.0716°; at the first division point (i=0), θ0=-90°, Xi=28×cos(-90°)=0mm, Zi=28×sin(-90°)=-28mm; at the 1257th division point (i=1256), θ1256=0°, Xi=28×cos0°=28mm, Zi=28×sin0°=0mm; the coordinates calculated by this equation can accurately fit the concave fillet curve, providing accurate trajectory data for subsequent incremental programming and avoiding the contour error caused by wear of traditional forming grinding wheels.

[0061] In an optional implementation, when machining convex fillets, the parametric equation is: ; ; Where Xi and Zi are the radial and axial coordinates of the i-th division point in the rectangular coordinate system, respectively, r is the journal radius of the crankshaft sprocket, and Φi is the central angle corresponding to the i-th division point.

[0062] Specifically, r remains 20mm, R is the radius of the convex fillet (specifically 2mm in this application), and the value of Φi gradually increases from 0° to 90°, with a step size Δφ = 90° / (n-1) (Δφ ≈ 0.2866° when n = 315).

[0063] The design of this parametric equation is based on the structural characteristics of the convex fillet. The convex fillet is located at the transition between the journal and the sprocket tooth tip, and the center of the circle needs to be in the negative X-axis direction (away from the tooth tip). Therefore, the coordinates of the center of the circle are (rR,0)=(18,0), which ensures that the trajectory of the dividing point fits the transition structure.

[0064] Taking R2 convex fillet as an example, at the first dividing point (i=0), Φ0=0°, Xi=18×cos0°=18mm, Zi=18×sin0°=0mm; at the 315th dividing point (i=314), Φ314=90°, Xi=18×cos90°=0mm, Zi=18×sin90°=18mm.

[0065] In actual machining, the starting point needs to be adjusted to the intersection of the outer circle of the journal (X=20mm) and the convex fillet (Z=5mm). The corresponding initial value of Φi is arccos(18 / 20)=arccos(0.9)=25.84°, ensuring accurate coordinate calculation. This equation can realize high-precision grinding of convex fillets, making up for the defect that traditional technology can only process concave fillets.

[0066] In an optional implementation, see Figure 5 As shown, Figure 5 The flowchart of a CNC program generation method provided in Embodiment 1 of this application is shown, wherein the step of generating a CNC program that controls the grinding wheel to move incrementally through each of the interpolation points according to the coordinates of the interpolation points includes steps S501 to S502: S501: Calculate the radial and axial movement increments of the grinding wheel based on the coordinates of adjacent interpolation points.

[0067] Specifically, the calculation of the moving increment needs to be based on the coordinates of each component point obtained from the parametric equations mentioned above. Taking R2 convex fillet as an example, n=315, the coordinates of each component point are calculated using Xi=18cosφi and Zi=18sinφi.

[0068] The coordinates of the first dividing point (i=0) are (X0, Z0) = (18 × cos0°, 18 × sin0°) = (18 mm, 0 mm); the coordinates of the second dividing point (i=1) are φ1 ≈ 0.2866°, X1 = 18 × cos0.2866° ≈ 17.998 mm, Z1 = 18 × sin0.2866° ≈ 0.010 mm.

[0069] Therefore, the radial increment ΔX1 = X1 - X0 ≈ 17.998 - 18 ≈ -0.002 mm, and the axial increment ΔZ1 = Z1 - Z0 ≈ 0.010 - 0 ≈ 0.010 mm, corresponding to the program instruction "G01X-0.002Z0.010F80". All increment values ​​must be retained to 4 decimal places to ensure movement accuracy and avoid contour deviation.

[0070] S502: Convert the incremental movement into incremental motion commands that the CNC system can recognize, and integrate them into a complete CNC machining program.

[0071] Specifically, the CNC system adopts the Fanuc 18i system, and the program includes initialization, spindle start, and positioning modules: the initialization command "G21 G90 G99 G40 G49" presets parameters; the spindle start command selects the speed according to the fillet type (concave fillet S=3800r / min, convex fillet S=1500r / min, both equipped with M03); the positioning command first moves to a safe position with "G00 X50.0 Z±10.0", and then feeds to the starting point with "G01 X20.0 Z±5.0 F100".

[0072] It also includes an incremental interpolation module: switch the incremental mode by “G91”, and write the instructions for each sub-point in sequence. For example, write 786 “G01 XΔXi ZΔZi F80” instructions for R5 concave fillet (the middle 780 instructions are omitted). The feed rate F=80mm / min (the value range is 20-60mm / min, balancing efficiency and accuracy).

[0073] Finally, it includes a tool retraction and end module: "G90" switches back to absolute mode, "G00 X50.0 Z±10.0" retracts to a safe position; "M05" stops the spindle, "M30" resets the program; the program needs to be labeled with its purpose (e.g., "O0001 (R5 concave fillet grinding program)"), to improve changeover efficiency and solve the problem of needing to re-edit and modify the program for changeover in traditional technology.

[0074] In an optional implementation, see Figure 6 As shown, Figure 6 The flowchart of a CNC program execution method provided in Embodiment 1 of this application is shown. The execution of the CNC program, controlling the grinding wheel to perform linear interpolation grinding along the trajectory formed by the interpolation points to process the fillet, includes steps S601-S604: S601: Position the grinding wheel at the grinding start point.

[0075] Specifically, before positioning the grinding wheel, the grinding wheel installation and debugging must be completed: the grinding wheel is a narrow grinding wheel with a width of 10mm (range 8-12mm, suitable for the narrow space at the root of the shaft diameter), a diameter of 450mm (to ensure stable linear speed), and a fillet radius of R1.3mm (equal to the minimum fillet radius to be processed, reducing initial contact error); after installation, the grinding wheel axis must be adjusted to be parallel to the crankshaft axis, and the runout must be checked to be ≤0.002mm.

[0076] The grinding wheel itself has a fillet radius of R1.3mm (equal to the minimum fillet radius to be processed), a width of 10mm (range 8-12mm), and a diameter of 450mm. After installation, the grinding wheel axis needs to be adjusted to be parallel to the crankshaft axis, and the runout should be checked to be ≤0.002mm.

[0077] The crankshaft must also be clamped: a combination of double ejector pins and a chuck is used for positioning to ensure that the coaxiality between the crankshaft axis and the grinding machine spindle axis is ≤0.003mm, thus avoiding machining errors caused by clamping deviations.

[0078] When positioning, first execute "G00 X50.0 Z-10.0" (taking R5 concave fillet as an example) to move to a safe position, and then execute "G01X20.0 Z-5.0 F100" to move to the starting point (intersection of the outer circle of the journal and the fillet) at a slow feed speed to ensure that the grinding wheel and the workpiece have a stable initial contact and avoid impact damage.

[0079] S602: Switch the CNC system to incremental programming mode.

[0080] Specifically, the mode switching is achieved through the "G91" command in the program. The core advantage of incremental mode is that the grinding wheel movement is based on the incremental value of adjacent interpolation points, without relying on the cumulative calculation of absolute coordinates, which can effectively avoid the accumulation of errors at multiple points (such as R8 concave fillet n=1257).

[0081] After switching, the system automatically records the current position as the incremental starting point, and all subsequent movements are calculated based on this point to determine the relative displacement. This adapts to the needs of multi-point continuous grinding and provides a guarantee for high-precision machining, which is different from the traditional form grinding wheel mode that relies on contour accuracy.

[0082] S603: Execute the incremental motion command to control the grinding wheel to pass through each of the interpolation points sequentially at a set feed speed for grinding.

[0083] Specifically, the feed rate F is set to 80 mm / min (within the range of 20-60 mm / min, preferred in this application, balancing efficiency and surface quality); the grinding wheel spindle speed is adjusted according to the fillet type: for concave fillets (R1.3, R5, R8), select S=3800 r / min (range of 3000-4000 r / min to ensure grinding force), and for convex fillets (R2), select S=1500 r / min (to avoid burning the tooth tip surface).

[0084] During execution, the CNC system controls the grinding wheel to move along the incremental command trajectory, approximating the arc contour through multiple short straight lines, with an interpolation error ≤0.001mm. For example, the R5 concave fillet is fitted through 786 short straight lines, resulting in minimal contour deviation.

[0085] The processing sequence is to first complete the concave and convex fillets of one sprocket, and then process the other two sprockets in sequence. During mass production, the accuracy needs to be sampled and checked every 50 pieces to ensure the consistency of the accuracy of batch processing and solve the problems of time-consuming changeover and accuracy fluctuations in traditional technology.

[0086] S604: After grinding is completed, switch to absolute programming mode and retract the grinding wheel to a safe position.

[0087] Specifically, after completing the current fillet grinding, first switch back to absolute programming mode using the "G90" command. This mode provides more precise coordinate positioning and facilitates the safe withdrawal of the grinding wheel.

[0088] Then execute "G00X50.0Z-10.0" (R5 concave fillet) or "G00X50.0Z10.0" (R2 convex fillet) to move the grinding wheel to a safe position away from the workpiece and avoid collision with the machined surface.

[0089] Finally, execute the "M05" stop spindle and "M30" reset program to prepare for the next fillet machining and improve production continuity.

[0090] In one optional implementation, the value of the single-point arc length increment ΔL ranges from 0.005mm to 0.015mm, and the grinding wheel is a narrow grinding wheel with a width of 8mm to 12mm, and its own corner radius is less than or equal to the minimum corner radius to be processed.

[0091] Specifically, the value of the single-point arc length increment ΔL needs to balance accuracy and efficiency: ΔL=0.005mm has the highest accuracy but the longest processing time, while ΔL=0.015mm has the highest efficiency but the lowest accuracy; this application prefers ΔL=0.01mm, which can meet IT6 level accuracy (corner radius tolerance ≤ ±0.005mm, journal size tolerance ≤ ±0.003mm), and is suitable for mass production scenarios.

[0092] The narrow grinding wheel parameters are designed with full consideration of the crankshaft structure and grinding requirements: the width is 8-12mm, preferably 10mm, to avoid interference with adjacent sprockets; the diameter is 450mm based on the grinding machine spindle specifications, and the linear speed calculation formula v=πDN / 1000 (when D=450mm, N=3800r / min, v≈5371m / min) conforms to the optimal linear speed range of CBN grinding wheels; the self-rounded radius R1.3mm is equal to the minimum radius of the rounded corner to be processed, reducing the initial contact stress and avoiding grinding wheel breakage or workpiece scratches.

[0093] This grinding wheel design can also significantly reduce costs: traditional technology requires three CBN forming grinding wheels with different contours to process three types of concave fillets (high unit price), while this application only requires one narrow grinding wheel to achieve cost reduction, solving the problem of high cost of traditional technology.

[0094] Example 2 See Figure 7 As shown, Figure 7 This illustration shows a structural schematic diagram of a crankshaft sprocket fillet grinding device according to Embodiment 2 of this application, wherein the device includes: The coordinate calculation module 701 is used to calculate the coordinates of multiple interpolation points for approximating the contour of the fillet based on the geometric parameters of the fillet to be processed. The program generation module 702 is used to generate a CNC program that controls the grinding wheel to move incrementally through each of the interpolation points according to the coordinates of the interpolation points. The program execution module 703 is used to execute the CNC program and control the grinding wheel to perform linear interpolation grinding along the trajectory formed by the interpolation points, thereby machining the fillet.

[0095] In an optional implementation, calculating the coordinates of multiple interpolation points for approximating the fillet profile based on the geometric parameters of the fillet to be processed includes: Calculate the fillet arc length L based on the fillet radius R and the preset central angle; Calculate the number n of equal arc length division points based on the arc length L and the set single-point arc length increment ΔL; Establish a rectangular coordinate system with the center of the crankshaft sprocket journal as the origin, and calculate the coordinates of each point by selecting the corresponding parametric equation based on whether the fillet is concave or convex.

[0096] In an optional implementation, when machining concave fillets, the parametric equation is: ; ; in, and The first The radial and axial coordinates of each point in the Cartesian coordinate system The journal radius of the crankshaft sprocket is [missing information]. For the first The central angles corresponding to the dividing points.

[0097] In an optional implementation, when machining convex fillets, the parametric equation is: ; ; in, and The first The radial and axial coordinates of each point in the Cartesian coordinate system The journal radius of the crankshaft sprocket is [missing information]. For the first The central angles corresponding to the dividing points.

[0098] In an optional implementation, generating a CNC program to control the grinding wheel to sequentially pass through each interpolation point in an incremental manner, based on the coordinates of the interpolation points, includes: Calculate the radial and axial movement increments of the grinding wheel based on the coordinates of adjacent interpolation points; The incremental movement is converted into incremental motion commands that the CNC system can recognize and integrated into a complete CNC machining program.

[0099] In an optional implementation, executing the CNC program to control the grinding wheel to perform linear interpolation grinding along the trajectory formed by the interpolation points, thereby machining the fillet, includes: Position the grinding wheel at the grinding start point; Switch the CNC system to incremental programming mode; The incremental motion command is executed to control the grinding wheel to pass through each interpolation point sequentially at a set feed rate for grinding. After grinding is complete, switch to absolute programming mode and retract the grinding wheel to a safe position.

[0100] In one optional implementation, the value of the single-point arc length increment ΔL ranges from 0.005mm to 0.015mm, and the grinding wheel is a narrow grinding wheel with a width of 8mm to 12mm, and its own corner radius is less than or equal to the minimum corner radius to be processed.

[0101] Example 3 Based on the same application concept, see [link / reference] Figure 8 As shown, Figure 8 This illustration shows a structural schematic diagram of a computer device provided in Embodiment 3 of this application, wherein, as shown... Figure 8 As shown, the computer device 800 provided in Embodiment 3 of this application includes: The computer device 800 includes a processor 801, a memory 802, and a bus 803. The memory 802 stores machine-readable instructions that can be executed by the processor 801. When the computer device 800 is running, the processor 801 communicates with the memory 802 through the bus 803. When the machine-readable instructions are executed by the processor 801, the steps of the crankshaft sprocket fillet grinding method shown in Embodiment 1 above are performed.

[0102] Example 4 Based on the same concept, this application also provides a computer-readable storage medium storing a computer program, which, when executed by a processor, performs the steps of the crankshaft sprocket fillet grinding method described in any of the above embodiments.

[0103] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working process of the system and apparatus described above can be referred to the corresponding process in the foregoing method embodiments, and will not be repeated here.

[0104] The computer program product for grinding crankshaft sprocket fillets provided in this application includes a computer-readable storage medium storing program code. The instructions included in the program code can be used to execute the methods described in the preceding method embodiments. For specific implementation details, please refer to the method embodiments, which will not be repeated here.

[0105] The crankshaft sprocket fillet grinding device provided in this application embodiment can be specific hardware on the equipment or software or firmware installed on the equipment. The implementation principle and technical effects of the device provided in this application embodiment are the same as those in the foregoing method embodiments. For the sake of brevity, any parts not mentioned in the device embodiment can be referred to the corresponding content in the foregoing method embodiments. Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can all be referred to the corresponding processes in the above method embodiments, and will not be repeated here.

[0106] In the embodiments provided in this application, it should be understood that the disclosed apparatus and methods can be implemented in other ways. The apparatus embodiments described above are merely illustrative. For example, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. Furthermore, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Additionally, the displayed or discussed mutual couplings, direct couplings, or communication connections may be through some communication interfaces; indirect couplings or communication connections between devices or units may be electrical, mechanical, or other forms.

[0107] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0108] In addition, the functional units in the embodiments provided in this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit.

[0109] If the aforementioned functions are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0110] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. In addition, the terms "first", "second", "third", etc. are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0111] Finally, it should be noted that the above-described embodiments are merely specific implementations of this application, used to illustrate the technical solutions of this application, and not to limit them. The protection scope of this application is not limited thereto. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that any person skilled in the art can still modify or easily conceive of changes to the technical solutions described in the foregoing embodiments, or make equivalent substitutions for some of the technical features, within the scope of the technology disclosed in this application; and these modifications, changes, or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application. All should be covered within the protection scope of this application. Therefore, the protection scope of this application should be determined by the protection scope of the claims.

Claims

1. A method of fillet grinding of a crankshaft sprocket, characterized by, The method comprises: According to the geometric parameters of the round corner to be processed, the coordinates of a plurality of interpolation points for approximating the round corner profile are calculated; According to the coordinates of the interpolation points, a numerical control program for controlling the grinding wheel to pass through each interpolation point in turn in an incremental movement manner is generated; The numerical control program is executed to control the grinding wheel to perform linear interpolation grinding along the trajectory formed by the interpolation points, thereby processing the round corner.

2. The crankshaft sprocket rounding method according to claim 1, characterized by, The method comprises: According to the round corner radius R and the preset central angle, the arc length L of the round corner is calculated; According to the arc length L and the set single-point arc length increment ΔL, the number n of equi-arc-length sub-points is calculated; A rectangular coordinate system with the center of the crankshaft sprocket journal round corner as the origin is established, and according to whether the round corner is a concave round corner or a convex round corner, a corresponding parametric equation is selected to calculate the coordinates of each sub-point.

3. The crankshaft sprocket rounding method according to claim 2, characterized by, When processing a concave round corner, the parametric equation is: ； ； wherein, and are the radial and axial coordinates of the first and second points in the rectangular coordinate system, is the journal radius of the crankshaft sprocket, is the central angle corresponding to the first and second points.

4. The crank sprocket rounding method according to claim 2, characterized by, When processing a convex round corner, the parametric equation is: Φi; ； wherein, and are the radial and axial coordinates of the i-th point in the rectangular coordinate system, are the radial and axial coordinates of the i-th point in the rectangular coordinate system, is the journal radius of the crankshaft sprocket, is the journal radius of the crankshaft sprocket, is the central angle corresponding to the i-th point.

5. The crankshaft sprocket rounding method of claim 1, wherein The method comprises: According to the coordinates of adjacent interpolation points, the movement increments of the grinding wheel in the radial and axial directions are calculated; The movement increments are converted into incremental motion instructions recognizable by the numerical control system, and are integrated into a complete numerical control machining program.

6. The crankshaft sprocket rounding method of claim 1, wherein The method comprises: The grinding wheel is positioned to the grinding starting point; The numerical control system is switched to the incremental programming mode; The incremental motion instructions are executed to control the grinding wheel to grind through each interpolation point in turn at a set feed rate; After grinding is completed, the absolute programming mode is switched to and the grinding wheel is exited to a safe position.

7. The crankshaft sprocket rounding method of claim 2, wherein The value range of the single-point arc length increment ΔL is 0.005mm to 0.015mm, and the grinding wheel is a narrow grinding wheel with a width of 8mm to 12mm and a self-round corner radius less than or equal to the smallest round corner radius to be processed.

8. A crankshaft sprocket rounding device characterized by, The device comprises: A coordinate calculation module for calculating the coordinates of a plurality of interpolation points for approximating the round corner profile according to the geometric parameters of the round corner to be processed; A program generation module for generating a numerical control program for controlling the grinding wheel to pass through each interpolation point in turn in an incremental movement manner according to the coordinates of the interpolation points; A program execution module for executing the numerical control program to control the grinding wheel to perform linear interpolation grinding along the trajectory formed by the interpolation points, thereby processing the round corner.

9. A computer device, comprising: It comprises: A processor, a memory and a bus, the memory stores machine readable instructions executable by the processor, when the computer device is running, the processor and the memory communicate through the bus, and the machine readable instructions are executed by the processor to perform the steps of the crankshaft sprocket round corner grinding method in any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that, The computer readable storage medium stores a computer program, which is executed by the processor to perform the steps of the crankshaft sprocket round corner grinding method in any one of claims 1 to 7.

Images