A method, system, equipment, and storage medium for machining a crankshaft center hole.

Abstract

This invention relates to the field of crankshaft center hole machining technology, specifically to a method, system, equipment, and storage medium for machining crankshaft center holes. The steps are as follows: Acquire the three-dimensional shape data of the crankshaft blank; determine the tolerance grade of the crankshaft blank and the corresponding provisional center hole position in a three-dimensional shape database; simulate the machining of the crankshaft blank using several provisional center hole positions as references to obtain the first imbalance vector of the final shape; acquire the second imbalance vector of the current machine tool side center drill and perform fusion analysis with the first imbalance vector to determine the dynamic imbalance vector of the crankshaft blank during the machining process on the machine tool side; calculate the center hole position closest to zero, and use this position as the center hole position of all crankshaft blanks of the same grade with the same second imbalance vector. This invention makes the crankshaft rotational imbalance after machining approach zero; furthermore, it can significantly improve center hole efficiency and reduce production costs.

Description

Technical Field

[0001] This invention relates to the field of crankshaft center hole machining technology, and more specifically, to a method, system, equipment, and storage medium for machining crankshaft center holes. Background Technology

[0002] The crankshaft is the most important component in an engine. It bears the force transmitted from the connecting rod and converts it into torque, which is then output through the crankshaft to drive other accessories on the engine. The crankshaft is subjected to the combined effects of centrifugal force from the rotating mass, periodically changing gas inertial force, and reciprocating inertial force, which subject the crankshaft to bending and torsional loads. Therefore, the crankshaft is required to have sufficient strength, rigidity, and balance.

[0003] Generally speaking, for engine crankshafts, the position of the center hole, which serves as the machining reference, is particularly important in order to suppress vibration during rotation. If the position accuracy of the center hole is poor, the imbalance of crankshaft rotation will increase. In addition, die forging is currently the main method for mass production of crankshafts. During die forging, a burr groove needs to be opened around the die cavity along the parting surface, thus forming a burr around the perimeter of the forged part, which needs to be removed on a trimming press. Therefore, there may still be significant differences between crankshaft blanks in the same batch. Therefore, setting the same center hole position for the same batch of crankshaft blanks to improve the machining efficiency may lead to a large number of defective products, which is not ideal. Therefore, the position of the center hole must be determined appropriately. Summary of the Invention

[0004] The purpose of this invention is to provide a method, system, device and storage medium for machining the center hole of a crankshaft, which, while ensuring the machining efficiency of the center hole, sets an appropriate center hole position for the crankshaft blank, thereby solving the problems pointed out in the background art.

[0005] The embodiments of the present invention are achieved through the following technical solution: a method for machining a crankshaft center hole, comprising the following steps:

[0006] Obtain the three-dimensional shape data of the crankshaft blank on the truss side, compare the three-dimensional shape data with the three-dimensional shape database, and determine the tolerance grade of the crankshaft blank and the positions of several provisional center holes corresponding to the tolerance grade.

[0007] Using the positions of the provisional center holes as references, the machining simulation of the crankshaft blank is performed to obtain the first unbalance vector under the final shape obtained after the machining simulation.

[0008] The second unbalance vector of the current machine tool side center drill is obtained and fused with the first unbalance vector to determine the dynamic unbalance vector of the crankshaft blank during the machining process on the machine tool side;

[0009] The center hole position that is closest to zero among the dynamic unbalance vectors obtained from the several provisional center hole positions is used as the center hole machining position of the crankshaft blank with the same second unbalance vector in the same tolerance grade.

[0010] When the loading is completed on the truss side, the machine tool side processes the center hole at the center hole machining position on the crankshaft blank.

[0011] According to a preferred embodiment, determining the tolerance grade of the crankshaft blank by comparing the three-dimensional shape data with a three-dimensional shape database includes:

[0012] Based on the three-dimensional shape data and the three-dimensional shape retrieval model, the target feature vector of the crankshaft blank is obtained;

[0013] Calculate the Euclidean distance between the target feature vector and the feature vectors corresponding to all tolerance grades of the three-dimensional shape data in the three-dimensional shape database, and take the tolerance grade corresponding to the three-dimensional shape data with the smallest Euclidean distance as the tolerance grade to which the crankshaft blank belongs.

[0014] According to a preferred embodiment, the step of obtaining the second imbalance vector of the current machine tool-side center drill and fusing it with the first imbalance vector to determine the dynamic imbalance vector of the crankshaft blank during the machine tool-side machining process includes:

[0015] Obtain the first displacement vector of the first imbalance vector on the rotation center line of the crankshaft blank and obtain the second displacement vector of the second imbalance vector on the machine tool side center drill;

[0016] Based on the first displacement vector of the first unbalance vector, the second displacement vector of the second unbalance vector is compensated for jitter rotational motion, and the compensated rotational center line during the machining process on the machine tool side is determined according to the compensated second displacement vector.

[0017] Using the compensated rotation center line as a reference, the machining simulation of the crankshaft blank is performed, and the unbalance vector under the final shape obtained after the machining simulation is used as the dynamic unbalance vector of the crankshaft blank during the machining process on the machine tool side.

[0018] According to a preferred embodiment, after designating this position as the machining position for the center hole of crankshaft blanks having the same second unbalance vector within the same tolerance grade, the method further includes:

[0019] The obtained center hole machining positions are associated and stored in the 3D shape database as provisional center hole positions for the corresponding tolerance level.

[0020] The present invention also provides a machining system for a crankshaft center hole, applied to the method described above, comprising:

[0021] The provisional center hole position determination unit is used to acquire the three-dimensional shape data of the crankshaft blank on the truss side, compare the three-dimensional shape data with the three-dimensional shape database, and determine the tolerance grade of the crankshaft blank and the positions of several provisional center holes corresponding to the tolerance grade.

[0022] The simulation unit is used to simulate the machining of the crankshaft blank by taking the positions of the several provisional center holes as references, and to obtain the first unbalance vector under the final shape obtained after the machining simulation.

[0023] The fusion analysis unit is used to obtain the second unbalance vector of the current machine tool side center drill and perform fusion analysis with the first unbalance vector to determine the dynamic unbalance vector of the crankshaft blank during the machining process on the machine tool side;

[0024] The center hole machining position determination unit is used to calculate the center hole position that is closest to zero among the dynamic unbalance vectors obtained from the plurality of provisional center hole positions, and to take this position as the center hole machining position of the crankshaft blank with the same second unbalance vector in the same tolerance grade.

[0025] The center hole machining unit is used to machine the center hole at the center hole machining position on the crankshaft blank on the machine tool side when the loading on the truss side is completed.

[0026] The present invention also provides an electronic device, comprising:

[0027] The memory stores execution instructions;

[0028] and a processor that executes the execution instructions stored in the memory, causing the processor to perform the method as described above.

[0029] The present invention also provides a readable storage medium storing executable instructions, which, when executed by a processor, are used to implement the method described above.

[0030] The technical solution of this invention has at least the following advantages and beneficial effects: According to the machining method of the center hole provided by this invention, the position of the center hole can be appropriately determined before the crankshaft blank is processed in a specified manner, so that the crankshaft rotational imbalance after the machining process approaches zero; in addition, setting the center hole position for crankshaft blanks of the same tolerance grade under the same machine tool side working conditions can greatly improve the center hole efficiency. Unlike the method of setting the same center hole position for the same batch of crankshaft blanks, this method has higher precision, can effectively reduce the proportion of defective products, and reduce production costs. Attached Figure Description

[0031] Figure 1 This is a schematic flowchart of the machining method for the center hole provided in Embodiment 1 of the present invention;

[0032] Figure 2 This is the CPU wiring diagram on the machine tool side provided in Embodiment 1 of the present invention;

[0033] Figure 3 This is the CPU wiring diagram on the truss side provided in Embodiment 1 of the present invention;

[0034] Figure 4 This is the EM wiring diagram for the machine tool side provided in Embodiment 1 of the present invention. Detailed Implementation

[0035] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, 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. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0036] Example 1

[0037] See Figure 1 As shown, Figure 1 This is a schematic flowchart of a method for machining a center hole according to an embodiment of the present invention.

[0038] The present invention provides a method for machining a crankshaft center hole, comprising the following steps:

[0039] 1) The steps for determining the provisional center hole position are as follows:

[0040] 1-1) The crankshaft blank on the truss side is scanned with a 3D laser to record the 3D coordinates and reflectivity information of the feature points on the surface of the crankshaft blank, and the information is uploaded to the processor. In this embodiment, the processor used is a Siemens S7-200 PLC. The preset program on the processor is used to reconstruct the 3D model of the crankshaft blank to obtain the 3D shape data of the crankshaft blank, and to realize the wiring work between the truss side and the machine tool side; see [link to documentation]. Figures 2 to 4 The diagram shown is a wiring diagram of the truss side and the machine tool side in an embodiment of the present invention. Automatic cyclic loading and unloading function can be realized through the control communication interface, and the details will not be elaborated further.

[0041] 1-2) Based on the comparison between the three-dimensional shape data and the three-dimensional shape database, determine the tolerance grade of the crankshaft blank and the positions of several provisional center holes corresponding to that tolerance grade. Specifically, in this embodiment, determining the tolerance grade of the crankshaft blank based on the comparison between the three-dimensional shape data and the three-dimensional shape database includes: obtaining the target feature vector of the crankshaft blank based on the three-dimensional shape data and the three-dimensional shape retrieval model; calculating the Euclidean distance between the target feature vector and the feature vectors corresponding to the three-dimensional shape data of all tolerance grades in the three-dimensional shape database, and taking the tolerance grade corresponding to the three-dimensional shape data with the smallest Euclidean distance as the tolerance grade of the crankshaft blank. It should be noted that for dimensional tolerances, the national standard divides tolerances into 20 grades according to different application scenarios, represented by IT01, IT0, IT1 to IT18 from high to low.

[0042] For geometric tolerances, according to GB / T 1184-1996, different cases should be considered, as follows:

[0043] (1) Straightness and flatness. Divided into 12 tolerance grades from 1 to 12, of which 6, 7, 8, and 9 are commonly used tolerance grades;

[0044] (2) Roundness and cylindricity. These are divided into 13 tolerance grades, from 0 to 12, with grades 7, 8, and 9 being the most commonly used.

[0045] (3) Parallelism, perpendicularity, and skewness. These are divided into 12 tolerance grades, from 1 to 12, with grades 6, 7, 8, and 9 being the most commonly used.

[0046] (4) Coaxiality, symmetry, circular runout and total runout. There are 12 tolerance grades from 1 to 12, of which 6, 7, 8 and 9 are commonly used tolerance grades.

[0047] To facilitate the identification of different tolerance grades and meet the machining requirements of setting appropriate center hole positions for crankshaft blanks of the same tolerance grade in most cases, this embodiment of the invention selects commonly used IT5 to IT12 for dimensional tolerances and 6 to 9 for geometric tolerances. Further, the three-dimensional shape data under different conditions are assigned corresponding dimensional and geometric tolerance grades and stored in a three-dimensional shape database. Several provisional center hole positions are matched to these data to form a linked list, completing the initial construction steps of the three-dimensional shape database. Subsequent updates are made to the provisional center hole positions in the linked list.

[0048] 2) Processing simulation steps, the specific steps are as follows:

[0049] 2-1) Using the positions of the provisional center holes as references, the crankshaft blank is processed in a simulated manner. Specifically, in this embodiment, after obtaining the three-dimensional shape data of the crankshaft blank, a provisional rotation center line is obtained based on the provisional center hole positions. The rotation center line is used as a reference to perform a preset processing simulation step for the three-dimensional shape data of the crankshaft blank. When there are multiple provisional center hole positions, multiple processing simulation steps are performed to obtain the simulated forming of all provisional center hole positions.

[0050] 2-2) By calculating the distance between the assumed rotation centerline and the simulated inertial spindle at the provisional center hole position, the first unbalance vector under the final shape obtained after machining simulation is obtained; wherein, if the difference between the rotation centerline and the inertial spindle is within a preset range, the crankshaft with the provisional center hole position as the reference for center hole machining has better dynamic balance.

[0051] 3) Fusion analysis steps, the specific steps are as follows:

[0052] 3-1) Obtain the second unbalance vector of the current machine tool side center drill and perform fusion analysis with the first unbalance vector; Specifically, in this embodiment, obtaining the second unbalance vector of the current machine tool side center drill and performing fusion analysis with the first unbalance vector includes: obtaining the first displacement vector of the first unbalance vector on the crankshaft blank rotation center line and obtaining the second displacement vector of the second unbalance vector on the machine tool side center drill; performing jitter rotational motion compensation on the second displacement vector of the second unbalance vector based on the first displacement vector of the first unbalance vector, and determining the compensation rotation center line in the machine tool side machining process based on the compensated second displacement vector, thus completing the fusion analysis step.

[0053] 3-2) Determine the dynamic imbalance vector of the crankshaft blank during the machining process on the machine tool side. The specific steps are as follows: Take the compensation rotation center line as the reference, perform machining simulation of the crankshaft blank, and obtain the imbalance vector under the final shape obtained after machining simulation as the dynamic imbalance vector of the crankshaft blank during the machining process on the machine tool side.

[0054] 4) Steps for determining the machining position of the center hole:

[0055] 4-1) Calculate the dynamic unbalance vector of the first unbalance vector of several provisional center hole positions, and then divide each calculated dynamic unbalance vector to obtain the center hole position that is closest to zero among the dynamic unbalance vectors.

[0056] 4-2) This position is used as the center hole machining position for all crankshaft blanks of the same tolerance grade and with the same second unbalance vector. This embodiment sets the center hole position for crankshaft blanks of the same tolerance grade under the same machine tool conditions, which can significantly improve the center hole efficiency. Unlike the method of setting the same center hole position for crankshaft blanks in the same batch, this method has higher precision, can effectively reduce the proportion of defective products, and reduce production costs.

[0057] Furthermore, in this embodiment, after using the position as the center hole machining position of the crankshaft blank with the same second unbalance vector in the same tolerance grade, the method further includes: storing the obtained center hole machining position in the corresponding linked list of the three-dimensional shape database as a provisional center hole position for the corresponding tolerance grade.

[0058] 5) Center hole machining steps, the specific steps are as follows: when the truss side is finished loading, the machine tool side machine the center hole at the center hole machining position on the crankshaft blank.

[0059] In summary, the center hole machining method provided by the present invention can appropriately determine the position of the center hole before performing the specified machining process on the crankshaft blank, so that the crankshaft rotational imbalance after the machining process approaches zero. In addition, setting the center hole position for crankshaft blanks of the same tolerance grade under the same machine tool side conditions can significantly improve the center hole efficiency. Unlike the method of setting the same center hole position for crankshaft blanks in the same batch, this method has higher precision, can effectively reduce the proportion of defective products, and reduce production costs.

[0060] Example 2

[0061] This invention provides a machining system for crankshaft center holes, applied to the method described in Embodiment 1, comprising:

[0062] The provisional center hole position determination unit is used to acquire the three-dimensional shape data of the crankshaft blank on the truss side, compare the three-dimensional shape data with the three-dimensional shape database, and determine the tolerance grade of the crankshaft blank and the positions of several provisional center holes corresponding to the tolerance grade.

[0063] The simulation unit is used to simulate the machining of the crankshaft blank by taking the positions of the several provisional center holes as references, and to obtain the first unbalance vector under the final shape obtained after the machining simulation.

[0064] The fusion analysis unit is used to obtain the second unbalance vector of the current machine tool side center drill and perform fusion analysis with the first unbalance vector to determine the dynamic unbalance vector of the crankshaft blank during the machining process on the machine tool side;

[0065] The center hole machining position determination unit is used to calculate the center hole position that is closest to zero among the dynamic unbalance vectors obtained from the plurality of provisional center hole positions, and to take this position as the center hole machining position of the crankshaft blank with the same second unbalance vector in the same tolerance grade.

[0066] The center hole machining unit is used to machine the center hole at the center hole machining position on the crankshaft blank on the machine tool side when the loading on the truss side is completed.

[0067] Example 3

[0068] This invention provides an electronic device, comprising:

[0069] The memory stores execution instructions;

[0070] and a processor that executes the execution instructions stored in the memory, causing the processor to perform the method as described in Embodiment 1.

[0071] Example 4

[0072] This invention provides a readable storage medium storing executable instructions, which, when executed by a processor, are used to implement the method described in Embodiment 1.

[0073] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for machining a crankshaft center hole, characterized in that, Includes the following steps: Obtain the three-dimensional shape data of the crankshaft blank on the truss side, compare the three-dimensional shape data with the three-dimensional shape database, and determine the tolerance grade of the crankshaft blank and the positions of several provisional center holes corresponding to the tolerance grade. Using the positions of the provisional center holes as references, the machining simulation of the crankshaft blank is performed to obtain the first unbalance vector under the final shape obtained after the machining simulation. The second unbalance vector of the current machine tool side center drill is obtained and fused with the first unbalance vector to determine the dynamic unbalance vector of the crankshaft blank during the machining process on the machine tool side. The center hole position that is closest to zero among the dynamic unbalance vectors obtained from the several provisional center hole positions is used as the center hole machining position of the crankshaft blank with the same second unbalance vector in the same tolerance grade. When the loading is completed on the truss side, the machine tool side processes the center hole at the center hole machining position on the crankshaft blank.

2. The method for machining the crankshaft center hole as described in claim 1, characterized in that, The step of comparing the three-dimensional shape data with a three-dimensional shape database to determine the tolerance grade of the crankshaft blank includes: Based on the three-dimensional shape data and the three-dimensional shape retrieval model, the target feature vector of the crankshaft blank is obtained; Calculate the Euclidean distance between the target feature vector and the feature vectors corresponding to all tolerance grades of the three-dimensional shape data in the three-dimensional shape database, and take the tolerance grade corresponding to the three-dimensional shape data with the smallest Euclidean distance as the tolerance grade to which the crankshaft blank belongs.

3. The method for machining the crankshaft center hole as described in claim 2, characterized in that, The step of obtaining the second imbalance vector of the current machine tool side center drill and fusing it with the first imbalance vector to determine the dynamic imbalance vector of the crankshaft blank during the machining process on the machine tool side includes: Obtain the first displacement vector of the first imbalance vector on the rotation center line of the crankshaft blank and obtain the second displacement vector of the second imbalance vector on the machine tool side center drill; Based on the first displacement vector of the first unbalance vector, the second displacement vector of the second unbalance vector is compensated for jitter rotational motion, and the compensated rotational center line during the machining process on the machine tool side is determined according to the compensated second displacement vector. Using the compensated rotation center line as a reference, the machining simulation of the crankshaft blank is performed, and the unbalance vector under the final shape obtained after the machining simulation is used as the dynamic unbalance vector of the crankshaft blank during the machining process on the machine tool side.

4. The method for machining the crankshaft center hole as described in claim 3, characterized in that, After designating this location as the center hole machining location for crankshaft blanks with the same second unbalance vector within the same tolerance grade, the process also includes: The obtained center hole machining positions are associated and stored in the 3D shape database as provisional center hole positions for the corresponding tolerance level.

5. A machining system for a crankshaft center hole, applied to the method as described in any one of claims 1 to 4, characterized in that, include: The provisional center hole position determination unit is used to acquire the three-dimensional shape data of the crankshaft blank on the truss side, compare the three-dimensional shape data with the three-dimensional shape database, and determine the tolerance grade of the crankshaft blank and the positions of several provisional center holes corresponding to the tolerance grade. The simulation unit is used to simulate the machining of the crankshaft blank by taking the positions of the several provisional center holes as references, and to obtain the first unbalance vector under the final shape obtained after the machining simulation. The fusion analysis unit is used to obtain the second unbalance vector of the current machine tool side center drill and perform fusion analysis with the first unbalance vector to determine the dynamic unbalance vector of the crankshaft blank during the machining process on the machine tool side; The center hole machining position determination unit is used to calculate the center hole position that is closest to zero among the dynamic unbalance vectors obtained from the plurality of provisional center hole positions, and to take this position as the center hole machining position of the crankshaft blank with the same second unbalance vector in the same tolerance grade. The center hole machining unit is used to machine the center hole at the center hole machining position on the crankshaft blank on the machine tool side when the loading on the truss side is completed.

6. An electronic device, characterized in that, include: The memory stores execution instructions; And a processor that executes the execution instructions stored in the memory, causing the processor to perform the method as described in any one of claims 1 to 4.

7. A readable storage medium, characterized in that, The readable storage medium stores execution instructions, which, when executed by a processor, are used to implement the method as described in any one of claims 1 to 4.

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