Crankshaft hard turning method and system based on multi-parameter monitoring

Abstract

The present application relates to the technical field of crankshaft surface grinding, and particularly relates to a crankshaft hard grinding method and system based on multi-parameter monitoring, wherein the method comprises the following steps: screening a grinding connection track segment of a grinding wheel across an oil hole position; capturing soundprint information of the grinding wheel in the grinding connection track segment; determining whether abnormality exists in grinding continuity based on a symmetry analysis result of an intensity curve of sound of the grinding wheel in the grinding connection track segment and determining a category of the abnormality in grinding continuity; and finally determining an adjustment mode of crankshaft grinding for different categories of the abnormality in grinding continuity. The system of the present application comprises a grinding assembly, a track screening module, an acquisition module, a quantification module, an abnormality analysis module and a grinding control module. The present application realizes real-time monitoring and dynamic adjustment of a connection process of contact, disconnection and recontact experienced by the grinding wheel across the oil hole, and improves the consistency of surface grinding on both sides of the oil hole.

Description

Technical Field

[0001] This invention relates to the field of crankshaft surface grinding technology, and more particularly to a crankshaft hard turning method and system based on multi-parameter monitoring. Background Technology

[0002] Hard turning is a crucial process in the crankshaft finishing stage. Machining accuracy determines the engine's power output efficiency, operational stability, and service life. For crankshafts with oil hole structures, the grinding continuity of surfaces adjacent to the oil hole locations is key to machining quality control. During crankshaft hard turning, when the grinding wheel crosses the oil hole location, it undergoes a transition process from contact with one side of the oil hole surface, gradually disengaging, and then contacting the other side. During this process, the contact area and pressure between the grinding wheel and the crankshaft change, causing fluctuations in the grinding state. Existing crankshaft hard turning methods mostly rely on preset fixed grinding parameters, lacking the ability to monitor and dynamically adjust the grinding transition process at the oil hole location in real time, making it difficult to accurately capture subtle anomalies during the grinding process.

[0003] For example, Chinese Patent Publication No. CN115091283A discloses a method and system for controlling and adjusting the grinding of crankshafts at high efficiency. The method includes: classifying multidimensional data information of the crankshaft using a crankshaft feature decision tree to obtain crankshaft feature information; performing finite element segmentation on crankshaft image information to obtain crankshaft image segmentation information; performing integrated learning based on the crankshaft feature information and crankshaft image segmentation information to construct an integrated analysis model for crankshaft grinding parameters; inputting the data information and image information of the crankshaft to be ground into the integrated analysis model to obtain crankshaft grinding parameter information; obtaining error parameters of the grinding device; and controlling and adjusting the crankshaft grinding based on the error parameters of the grinding device and the crankshaft grinding parameter information. This achieves the determination of crankshaft grinding parameters by constructing an integrated analysis model for crankshaft grinding parameters.

[0004] Existing technologies do not consider real-time monitoring and dynamic adjustment of the contact, disengagement, and re-contact process experienced by the grinding wheel when crossing the oil hole, resulting in poor grinding consistency on both sides of the oil hole, which affects the accuracy and stability of crankshaft hard turning. Summary of the Invention

[0005] To address this issue, the present invention provides a crankshaft hard turning method and system based on multi-parameter monitoring, which overcomes the problem that the prior art cannot monitor and dynamically adjust the contact, disengagement, and re-contact process experienced by the grinding wheel when crossing the oil hole in real time, resulting in poor grinding consistency on both sides of the oil hole.

[0006] To achieve the above objectives, the present invention provides a crankshaft hard turning method based on multi-parameter monitoring, comprising:

[0007] The movement trajectory of the grinding wheel's center point is obtained in advance, and the grinding connection trajectory segment where the grinding wheel crosses the oil hole is selected;

[0008] The acoustic signature information of the grinding wheel grinding within the grinding connection trajectory segment is captured, and an intensity curve of the sound intensity of the grinding wheel contacting the crankshaft surface as a function of the position of the grinding wheel center point is constructed based on the acoustic signature information.

[0009] Based on the symmetry analysis of the intensity curve, determine whether there is an abnormality in the grinding continuity of the grinding wheel on the adjacent surfaces at the oil hole location;

[0010] In response to an anomaly in the grinding continuity of adjacent surfaces at the oil hole location, the category of the grinding continuity anomaly is determined based on the positional deviation analysis results of the characteristic explicit points on the intensity curve.

[0011] For different categories of grinding continuity abnormalities, the adjustment method for crankshaft grinding is determined by adjusting the feed speed of the grinding wheel within the grinding connection trajectory segment, or adjusting the clamping force of the clamps at both ends of the crankshaft.

[0012] Furthermore, the process of selecting the grinding trajectory segment where the grinding wheel crosses the oil hole includes:

[0013] Obtain the 3D model data of the crankshaft and extract the center coordinates and diameter of the oil holes;

[0014] Establish a crankshaft machining space coordinate system, map the pre-acquired grinding wheel center point movement trajectory into the crankshaft machining space coordinate system, and determine the trajectory segment of the preset length as the grinding connection trajectory segment with the oil hole center coordinate as the midpoint;

[0015] The preset length is determined based on the aperture size.

[0016] Furthermore, the process of constructing an intensity curve showing how the sound intensity varies with the center point position of the grinding wheel includes:

[0017] Extract the sound intensity parameters corresponding to each sampling time from the voiceprint information;

[0018] The position coordinates of the grinding wheel center point in the machining space coordinate system are recorded in real time at each sampling moment to determine the distance between the grinding wheel center point and the center coordinates of the oil hole;

[0019] Plot an intensity curve of sound intensity as the position of the grinding wheel center point, with the distance as the x-axis and the sound intensity parameter as the y-axis.

[0020] Furthermore, the process of determining the curve symmetry analysis results of the intensity curve includes:

[0021] The boundary line is determined by using the abscissa of the oil hole center as the boundary, and the intensity curve is divided into the first characteristic curve segment and the second characteristic curve segment.

[0022] Several sets of symmetrical position points about the boundary line are selected on the first feature curve segment and the second feature curve segment respectively, and the sound intensity value corresponding to each set of symmetrical position points is extracted.

[0023] Calculate and record the absolute value of the sound intensity difference at each symmetrical location point.

[0024] Furthermore, the process of determining whether there is an abnormality in the grinding continuity between the grinding wheel and the adjacent surface at the oil hole location includes:

[0025] The absolute value of the sound intensity difference is compared with a preset intensity difference threshold.

[0026] If the absolute value of the sound intensity difference between any set of symmetrical positions is less than or equal to the intensity difference threshold, it is determined that there is no abnormality in the grinding continuity of the grinding wheel on the adjacent surface at the oil hole position.

[0027] If the absolute value of the sound intensity difference at any set of symmetrical locations is greater than the intensity difference threshold, it is determined that there is an abnormality in the grinding continuity of the grinding wheel on the adjacent surface at the oil hole location.

[0028] Furthermore, the process of determining the category of grinding continuity anomalies includes:

[0029] Extract the x-axis coordinates of the dominant feature points;

[0030] Calculate the deviation distance between the horizontal axis coordinate of the characteristic visible point and the center coordinate of the oil hole, and compare the deviation distance value with a preset deviation reference value;

[0031] If the deviation distance value is less than or equal to the deviation reference value, then the grinding continuity abnormality is determined to be the first abnormality category;

[0032] If the deviation distance value is greater than the deviation reference value, then the grinding continuity abnormality is determined to be the second abnormality category;

[0033] The characteristic point is the point on the intensity curve corresponding to the maximum sound intensity.

[0034] Furthermore, the process of determining the adjustment method for crankshaft grinding based on different categories of grinding continuity anomalies includes:

[0035] If the grinding continuity abnormality is classified as the first abnormality category, then the adjustment method for crankshaft grinding is determined to be adjusting the feed rate of the grinding wheel within the grinding connection trajectory segment;

[0036] If the grinding continuity abnormality is classified as the second abnormality category, then the adjustment method for crankshaft grinding is determined to be adjusting the clamping force of the clamps at both ends of the crankshaft.

[0037] Furthermore, the process of adjusting the feed speed of the grinding wheel and the clamping force of the clamps at both ends of the crankshaft includes:

[0038] Adjust the feed speed of the grinding wheel in the grinding connection trajectory segment and the clamping force of the clamps at both ends of the crankshaft according to the grinding anomaly coefficient of the connection surface;

[0039] The feed rate is negatively correlated with the grinding anomaly coefficient of the connecting surface, while the clamping force of the clamps at both ends of the crankshaft is positively correlated with the grinding anomaly coefficient of the connecting surface.

[0040] Furthermore, the grinding anomaly coefficient of the connecting surface is the ratio of the average absolute value of the sound intensity difference at all symmetrical positions to a preset sound intensity benchmark value.

[0041] Furthermore, the present invention also provides a crankshaft hard turning system based on multi-parameter monitoring, comprising:

[0042] The grinding assembly includes a clamp for holding the spindles at both ends of the crankshaft and a grinding wheel for grinding the surface of the crankshaft.

[0043] The trajectory filtering module is used to pre-obtain the movement trajectory of the grinding wheel's center point and filter out the trajectory segments where the grinding wheel crosses the oil hole.

[0044] The acquisition module, which is connected to the trajectory filtering module, includes an acoustic fingerprint acquisition unit for capturing acoustic fingerprint information of the grinding wheel within the trajectory segment and a distance acquisition unit for obtaining the deviation distance value between the center point of the grinding wheel and the center of the oil hole.

[0045] A quantization module, which is connected to the acquisition module, is used to construct an intensity curve of the sound intensity of the grinding wheel contacting the crankshaft surface as a function of the position of the center point of the grinding wheel.

[0046] An anomaly analysis module, which is connected to the quantization module, is used to determine whether there is an anomaly in the grinding continuity of the grinding wheel on the adjacent surface at the oil hole location and to determine the type of grinding continuity anomaly.

[0047] The grinding control module is connected to the anomaly analysis module and the grinding assembly, respectively, and is used to adjust the grinding wheel feed speed for different anomaly categories, or to adjust the clamping force of the clamps at both ends of the crankshaft.

[0048] The beneficial effects of the technical solution presented in this application include: pre-acquiring the movement trajectory of the grinding wheel's center point to screen out the grinding connection trajectory segment where the grinding wheel crosses the oil hole; capturing the acoustic signature information of the grinding wheel within the grinding connection trajectory segment, and constructing an intensity curve of the sound intensity based on the acoustic signature information of the grinding wheel within the grinding connection trajectory segment; determining whether there is an abnormality in grinding continuity based on the curve symmetry analysis results, and determining the category of grinding continuity abnormality based on the positional deviation analysis results of the characteristic explicit points on the intensity curve; finally, determining to adjust the feed speed of the grinding wheel within the grinding connection trajectory segment, or adjusting the clamping force of the clamps at both ends of the crankshaft, for different categories of grinding continuity abnormalities. Furthermore, this achieves real-time monitoring and dynamic adjustment of the contact, disengagement, and re-contact process experienced by the grinding wheel when crossing the oil hole, improving the consistency of grinding on both sides of the oil hole surface.

[0049] Furthermore, the present invention defines the trajectory segment range with the center of the oil hole as the midpoint, which can completely cover the entire connection process of the grinding wheel separating from the surface of one side of the oil hole, crossing the oil hole, and then contacting the surface of the other side, ensuring that the selected trajectory segment accurately corresponds to the key area where the grinding state is prone to fluctuation.

[0050] Furthermore, by constructing an intensity curve of sound intensity, this invention ensures that each sound intensity data point corresponds to a specific position of the grinding wheel as it crosses the oil hole, thereby transforming discrete sampling data into continuous curve features and intuitively presenting the sound intensity variation law of the grinding wheel throughout the entire process from approaching the oil hole, crossing the oil hole, to moving away from the oil hole.

[0051] Furthermore, during the symmetrical movement of the grinding wheel across the oil hole, the position with the greatest contact pressure should coincide with the center of the oil hole, and the horizontal axis coordinate of the characteristic point should theoretically be consistent with the coordinate of the center of the oil hole. By extracting the horizontal axis coordinate of the characteristic point and calculating its deviation distance from the coordinate of the center of the oil hole, the degree of offset of the key grinding position can be quantitatively characterized, directly reflecting the deviation direction of the grinding state, and realizing real-time monitoring of the contact, disengagement, and re-contact process experienced by the grinding wheel when crossing the oil hole.

[0052] Furthermore, under the first abnormal category, the present invention reduces the feed speed of the grinding wheel, prolongs the contact time between the grinding wheel and the crankshaft surface within the grinding connection trajectory segment, buffers the pressure fluctuations caused by the sudden change in the contact surface, and corrects the symmetry of the grinding state on both sides of the oil hole. Under the second abnormal category, the invention increases the clamping force of the fixture to improve the rigidity and stability of the crankshaft during rotation, suppresses the shaft offset, and makes the relative motion between the grinding wheel and the crankshaft return to the preset trajectory. This enables real-time monitoring and dynamic adjustment of the connection process of contact, disengagement, and re-contact experienced by the grinding wheel when crossing the oil hole, thereby improving the consistency of grinding on both sides of the oil hole surface. Attached Figure Description

[0053] Figure 1 This is a flowchart illustrating the crankshaft hard turning method based on multi-parameter monitoring in an embodiment of the present invention.

[0054] Figure 2 A flowchart illustrating the steps for determining the curve symmetry analysis results in an embodiment of the present invention;

[0055] Figure 3 This is a schematic diagram of the intensity curve in an embodiment of the present invention;

[0056] Figure 4 A flowchart illustrating the logic for determining whether there is an abnormality in grinding continuity according to an embodiment of the present invention;

[0057] Figure 5 This is a system block diagram of a crankshaft hard turning system based on multi-parameter monitoring, according to an embodiment of the present invention. Detailed Implementation

[0058] To make the objectives and advantages of the present invention clearer, the present invention will be further described below with reference to embodiments; it should be understood that the specific embodiments described herein are merely for explaining the present invention and are not intended to limit the present invention.

[0059] Preferred embodiments of the present invention will now be described with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are merely illustrative of the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0060] It should be noted that in the description of this invention, the terms "upper," "lower," "inner," "outer," etc., which indicate the direction or positional relationship, are based on the direction or positional relationship shown in the drawings. This is only for the convenience of description and is not intended to indicate or imply that the device or element must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of this invention.

[0061] It should be understood that although the terms "first," "second," etc., may be used in this invention to describe various types of information, these information should not be limited to these terms. These terms are only used to distinguish information of the same type from one another. For example, without departing from the scope of this invention, first information may also be referred to as second information, and similarly, second information may also be referred to as first information.

[0062] Furthermore, it should be noted that, in the description of this invention, unless otherwise explicitly specified and limited, the terms "installation" and "connection" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0063] Please see Figure 1 The diagram illustrates the steps of a crankshaft hard turning method based on multi-parameter monitoring according to an embodiment of the present invention. The crankshaft hard turning method based on multi-parameter monitoring of the present invention includes:

[0064] Step S100: Pre-acquire the movement trajectory of the grinding wheel center point and select the grinding connection trajectory segment where the grinding wheel crosses the oil hole position;

[0065] The present invention does not specify the method for obtaining the movement trajectory of the grinding wheel center point. It can be obtained by a servo motor encoder that controls the movement of the grinding wheel. The servo motor encoder stores the movement trajectory of the mechanical parts, which will not be described in detail here.

[0066] Step S200: Capture the acoustic information of the grinding wheel grinding within the grinding connection trajectory segment, and construct an intensity curve of the sound intensity of the grinding wheel contacting the crankshaft surface as a function of the position of the grinding wheel center point based on the acoustic information.

[0067] The present invention does not specifically limit the method of acquiring voiceprint information. It can be acquired by an industrial microphone mounted on a fixed frame of a grinding wheel, using a bandpass filter to filter ambient noise below 5kHz, and the interval between adjacent sampling times is 1s.

[0068] Step S300: Determine whether there is an abnormality in the grinding continuity of the grinding wheel on the adjacent surface at the oil hole position based on the curve symmetry analysis results of the strength curve.

[0069] Step S400: In response to the abnormal grinding continuity of the adjacent surfaces at the oil hole location, the category of grinding continuity abnormality is determined based on the positional deviation analysis results of the characteristic explicit points on the intensity curve.

[0070] Step S500: For different categories of grinding continuity abnormalities, determine the adjustment method for crankshaft grinding, which is to adjust the feed speed of the grinding wheel in the grinding connection trajectory segment, or to adjust the clamping force of the clamps at both ends of the crankshaft.

[0071] The fixture in this invention is a three-jaw linkage fixture, which is widely used in grinding processes to fix parts. This is common knowledge and will not be elaborated here.

[0072] Specifically, the process of selecting the grinding trajectory segment where the grinding wheel crosses the oil hole includes:

[0073] Obtain the 3D model data of the crankshaft and extract the center coordinates and diameter of the oil holes;

[0074] Establish a crankshaft machining space coordinate system, map the pre-acquired grinding wheel center point movement trajectory into the crankshaft machining space coordinate system, and determine the trajectory segment of the preset length as the grinding connection trajectory segment with the oil hole center coordinate as the midpoint;

[0075] The preset length is determined based on the aperture size.

[0076] In this invention, the preset length of the grinding connection trajectory segment = oil hole diameter × trajectory segment length determination factor, and the value range of the trajectory segment length determination factor is [5,10]. Optionally, the trajectory segment length determination factor can be set to 7.

[0077] In this invention, the three-dimensional model data of the crankshaft can be acquired by a scanner with three-dimensional scanning function, and the center coordinates and diameter of the oil hole can be determined by acquiring point cloud data.

[0078] In this invention, the origin of the crankshaft machining space coordinate system is the center of the main journal at one end of the crankshaft. The X-axis of the crankshaft machining space coordinate system is along the crankshaft axis, the Y-axis is perpendicular to the axis and parallel to the horizontal plane, and the Z-axis is perpendicular to the horizontal plane.

[0079] In this invention, the oil hole center coordinates and hole diameter are extracted by acquiring crankshaft three-dimensional model data to clarify the specific spatial position and morphological characteristics of the oil hole in the crankshaft structure. By mapping the pre-acquired grinding wheel center point movement trajectory to this coordinate system, the grinding wheel movement trajectory and the spatial position of the crankshaft and oil hole can be uniformly adapted, eliminating positional deviations under different coordinate systems, and making the relative positional relationship between the grinding wheel trajectory and the oil hole quantifiable.

[0080] It is understandable that as the grinding wheel approaches the oil hole and completely crosses it, its center point will form a continuous trajectory with the center of the oil hole as the center of symmetry. The range is defined with the center of the oil hole as the midpoint, which can completely cover the entire connection process of the grinding wheel separating from the surface of one side of the oil hole, crossing the oil hole, and then contacting the surface of the other side. This ensures that the selected trajectory segment accurately corresponds to the key area where the grinding state is prone to fluctuation.

[0081] Specifically, the process of constructing an intensity curve that varies in sound intensity with the position of the grinding wheel's center point includes:

[0082] Extract the sound intensity parameters corresponding to each sampling time from the voiceprint information;

[0083] The position coordinates of the grinding wheel center point in the machining space coordinate system are recorded in real time at each sampling moment to determine the distance between the grinding wheel center point and the center coordinates of the oil hole;

[0084] Plot an intensity curve of sound intensity as the position of the grinding wheel center point, with the distance as the x-axis and the sound intensity parameter as the y-axis.

[0085] In this invention, the unit of the horizontal axis value of the intensity curve is mm, and the unit of the vertical axis value is dB.

[0086] Understandably, changes in the contact area and pressure between the grinding wheel and the crankshaft surface directly cause fluctuations in sound intensity. During grinding, the contact area on both sides of the oil hole decreases and increases respectively. Theoretically, extracting sound intensity parameters can accurately capture the grinding contact state at every instant. By recording the position coordinates of the grinding wheel's center point in the machining space coordinate system at each sampling moment and calculating its distance from the oil hole's center coordinates, the spatial positional relationship of the grinding wheel relative to the oil hole can be accurately quantified. This clarifies the grinding wheel movement nodes corresponding to changes in sound intensity, ensuring that each sound intensity data point corresponds to the specific position of the grinding wheel as it crosses the oil hole. Plotting an intensity curve with the distance between the grinding wheel's center point and the oil hole's center as the abscissa and the sound intensity parameter as the ordinate, this transforms discrete sampling data into continuous curve features, intuitively presenting the sound intensity change pattern of the grinding wheel throughout the entire process of approaching, crossing, and moving away from the oil hole.

[0087] Specifically, please refer to Figure 2 The diagram illustrates the steps for determining the curve symmetry analysis results according to an embodiment of the present invention. The process for determining the curve symmetry analysis results of the intensity curve includes:

[0088] Step S301: Determine the dividing line using the abscissa of the oil hole center as the boundary line, and divide the intensity curve into a first characteristic curve segment and a second characteristic curve segment.

[0089] Step S302: Select several sets of symmetrical position points about the boundary line on the first feature curve segment and the second feature curve segment respectively, and extract the sound intensity value corresponding to each set of symmetrical position points;

[0090] Step S303: Calculate and record the absolute value of the sound intensity difference at each symmetrical location point.

[0091] Please see Figure 3As shown, this is a schematic diagram of the strength curve in an embodiment of the present invention. The abscissa of the oil hole center is 'a'. The curve segment in the abscissa interval Q1 is denoted as the first characteristic curve segment, and the curve segment in the abscissa interval Q2 is denoted as the second characteristic curve segment. b1 on the first characteristic curve segment and b2 on the second characteristic curve segment are a set of position points symmetrical about the boundary line. To facilitate the analysis of curve symmetry, as shown... Figure 3 As shown, the abscissa of the center coordinate of the oil hole can be determined as the origin on the abscissa. The distance when the center of the grinding wheel is on one side of the center of the oil hole is set to a negative value, that is, the distance between the center point of the grinding wheel and the center coordinate of the oil hole is displayed in the abscissa interval Q1. The distance when the center of the grinding wheel is on the other side of the center of the oil hole is set to a positive value, that is, the distance between the center point of the grinding wheel and the center coordinate of the oil hole is displayed in the abscissa interval Q2. Since the absolute values ​​of the distances b1 and b2 are equal, b1 and b2 are determined to be a set of position points symmetrical about the boundary line.

[0092] In this invention, the number of sets of symmetrical position points about the dividing line on the first and second feature curve segments is 10, and the spacing between the position points on each feature curve segment can be 1 / 4 of the oil hole diameter.

[0093] It is understandable that the present invention uses the abscissa of the center of the oil hole as the boundary line to determine the dividing line because the grinding wheel moves almost symmetrically around the oil hole when crossing it. Using this as the dividing line to divide the first and second characteristic curve segments can accurately correspond to the intensity change range corresponding to the grinding trajectory on both sides of the oil hole. By selecting several sets of symmetrical position points on the two curve segments and extracting the corresponding sound intensity values, the intensity comparison of discrete points is used to achieve a quantitative characterization of the overall curve symmetry. Theoretically, the symmetrical position points correspond to the grinding state of the grinding wheel at the same distance on both sides of the oil hole. The absolute value of the sound intensity difference of each set of symmetrical position points corresponds to the degree of difference in the grinding state on both sides.

[0094] Specifically, please refer to Figure 4 As shown, this is a logic flowchart of an embodiment of the present invention for determining whether there is an abnormality in grinding continuity. The process of determining whether there is an abnormality in the grinding continuity of the grinding wheel on the adjacent surface at the oil hole location includes:

[0095] The absolute value of the sound intensity difference is compared with a preset intensity difference threshold.

[0096] If the absolute value of the sound intensity difference between any set of symmetrical positions is less than or equal to the intensity difference threshold, it is determined that there is no abnormality in the grinding continuity of the grinding wheel on the adjacent surface at the oil hole position.

[0097] If the absolute value of the sound intensity difference at any set of symmetrical locations is greater than the intensity difference threshold, it is determined that there is an abnormality in the grinding continuity of the grinding wheel on the adjacent surface at the oil hole location.

[0098] In this invention, the strength difference threshold is the upper limit set by the technician for the difference in grinding state between the grinding wheel and the oil hole. To effectively distinguish between normal errors and abnormal deviations, the strength difference threshold can be determined through a pre-grinding test: select no fewer than 8 standard crankshaft test pieces of the same material and specifications as the target crankshaft, and use grinding wheels and fixtures consistent with the actual machining; adopt conventional crankshaft hard turning machining parameters in the art, setting the grinding wheel feed rate to 10 mm / min, the fixture clamping force to 500 N, and the grinding wheel speed to [missing information]. At a speed of 2000 r / min, acoustic information of the grinding wheel crossing the oil hole connection trajectory segment is collected during the grinding process to construct an acoustic intensity curve. Ten sets of symmetrical position points are selected, and the absolute value of the acoustic intensity difference of each set of symmetrical points is calculated. The absolute value of the intensity difference of symmetrical points of all standard specimens is statistically analyzed. Optionally, under the condition that the crankshaft is made of high-strength alloy steel, 1.2 times the maximum absolute value of the intensity difference of symmetrical points of all standard specimens is taken as the value of the intensity difference threshold. In this invention, the intensity difference threshold is 4 dB.

[0099] Understandably, during normal grinding, the difference in sound intensity at symmetrical positions should be controlled within a threshold. That is, when the absolute value of any set of differences is less than or equal to the threshold, it indicates that the grinding contact state on both sides is uniform and there is no obvious difference, and the grinding continuity can be judged to be normal. If the absolute value of any set of differences is greater than the threshold, it indicates that the grinding contact state at the corresponding position deviates from the symmetrical pattern, and there may be problems such as abrupt changes in the contact surface and uneven grinding force, thus judging that the grinding continuity is abnormal.

[0100] Specifically, the process of determining the category of grinding continuity anomalies includes:

[0101] Extract the x-axis coordinates of the dominant feature points;

[0102] Calculate the deviation distance between the horizontal axis coordinate of the characteristic visible point and the center coordinate of the oil hole, and compare the deviation distance value with a preset deviation reference value;

[0103] If the deviation distance value is less than or equal to the deviation reference value, then the grinding continuity abnormality is determined to be the first abnormality category;

[0104] If the deviation distance value is greater than the deviation reference value, then the grinding continuity abnormality is determined to be the second abnormality category;

[0105] The characteristic point is the point on the intensity curve corresponding to the maximum sound intensity.

[0106] In practice, to avoid the inability to select a unique characteristic point when there are multiple maximum sound intensity points, the maximum sound intensity point with the smallest abscissa distance from the center coordinate of the oil hole is selected as the characteristic characteristic point when there are multiple maximum sound intensity points.

[0107] In this invention, the deviation reference value is used to distinguish the abnormality category. The value of the deviation reference value can be determined according to the oil hole diameter. Optionally, the deviation reference value = oil hole diameter × 0.3.

[0108] It is understandable that during the symmetrical movement of the grinding wheel across the oil hole, the position with the greatest contact pressure should coincide with the center of the oil hole, and the horizontal axis coordinate of the characteristic point should theoretically be consistent with the coordinate of the oil hole center. Extracting the horizontal axis coordinate of this characteristic point and calculating its deviation from the oil hole center coordinate can quantitatively characterize the degree of offset of the key grinding position, directly reflecting the direction of deviation in the grinding state. If the deviation distance is less than or equal to the reference value, it indicates that the characteristic point has not fundamentally shifted due to crankshaft axis wobble, but rather that unreasonable parameters such as the grinding wheel feed rate have led to inconsistent grinding conditions on both sides of the oil hole; this situation is classified as the first anomaly category. If the deviation distance is greater than the reference value, it indicates that insufficient clamping force during crankshaft rotation has caused axis wobble; this situation is classified as the second anomaly category. This allows for precise classification of anomaly categories.

[0109] Specifically, the process of determining the adjustment method for crankshaft grinding based on different categories of grinding continuity abnormalities includes:

[0110] If the grinding continuity abnormality is classified as the first abnormality category, then the adjustment method for crankshaft grinding is determined to be adjusting the feed rate of the grinding wheel within the grinding connection trajectory segment;

[0111] If the grinding continuity abnormality is classified as the second abnormality category, then the adjustment method for crankshaft grinding is determined to be adjusting the clamping force of the clamps at both ends of the crankshaft.

[0112] Understandably, the first anomaly category is due to an unreasonable grinding wheel feed rate. The contact time and pressure between the grinding wheel and the crankshaft surface deviate from the optimal range, disrupting the symmetrical relationship of sound intensity during the decreasing and increasing contact surfaces on both sides of the oil hole. Therefore, adjusting the feed rate of the grinding wheel within the grinding connection trajectory segment can correct the grinding consistency of both surfaces by changing the dynamic process of grinding contact. The second anomaly category is due to crankshaft shaft wobble. Insufficient clamping force can cause radial runout of the crankshaft during rotary grinding, causing the relative position of the grinding wheel and crankshaft to deviate from the preset trajectory. Therefore, adjusting the clamping force of the clamps at both ends of the crankshaft can enhance the stability of the crankshaft during rotation, suppress shaft wobble, and bring the relative motion of the grinding wheel and crankshaft back to the preset trajectory, ensuring the grinding quality of the oil hole position.

[0113] Specifically, the process of adjusting the feed speed of the grinding wheel and the clamping force of the clamps at both ends of the crankshaft includes:

[0114] Adjust the feed speed of the grinding wheel in the grinding connection trajectory segment and the clamping force of the clamps at both ends of the crankshaft according to the grinding anomaly coefficient of the connection surface;

[0115] The feed rate is negatively correlated with the grinding anomaly coefficient of the connecting surface, while the clamping force of the clamps at both ends of the crankshaft is positively correlated with the grinding anomaly coefficient of the connecting surface.

[0116] For example, the specific adjustment method of the feed rate is determined according to the grinding anomaly coefficient of the joint surface. The reference value Kc of the grinding anomaly coefficient of the joint surface is set to 0.03, which is a dimensionless coefficient.

[0117] When the grinding anomaly coefficient of the mating surface is (Kc, 1.1Kc], the feed rate is reduced by 5%;

[0118] When the grinding anomaly coefficient of the mating surface is (1.1Kc, 1.2Kc], the feed rate is reduced by 10%;

[0119] When the grinding anomaly coefficient of the mating surface is greater than 1.2Kc, the feed rate is reduced by 15%;

[0120] The feed rate can be reduced by a maximum of 15% to avoid excessive parameter adjustment that could lead to substandard surface finish.

[0121] For example, the specific adjustment method of the clamping force of the clamps at both ends of the crankshaft is determined according to the grinding anomaly coefficient of the mating surface.

[0122] When the grinding anomaly coefficient of the mating surface is (Kc, 1.1Kc], the clamping force increases by 3%;

[0123] When the grinding anomaly coefficient of the mating surface is (1.1Kc, 1.2Kc], the clamping force increases by 6%;

[0124] When the grinding anomaly coefficient of the mating surface is greater than 1.2Kc, the clamping force is increased by 10%;

[0125] The clamping force is increased to a maximum of 10% of the initial clamping force to avoid excessive clamping force that could damage the crankshaft.

[0126] Understandably, the grinding anomaly coefficient of the connecting surface is a quantitative index calculated based on the degree of difference in grinding conditions on both sides of the oil hole. Its value reflects the degree of grinding continuity anomaly; the larger the coefficient, the greater the deviation of the grinding state from the ideal symmetry. Setting the feed rate and anomaly coefficient as negatively correlated is because a larger coefficient indicates a more significant imbalance in the grinding contact pressure and contact state on both sides. In this case, the grinding wheel feed rate needs to be reduced to prolong the contact time between the grinding wheel and the crankshaft surface within the grinding connection trajectory segment, buffering the pressure fluctuations caused by abrupt changes in the contact surface and correcting the symmetry of the grinding state on both sides of the oil hole. Setting the clamping force and anomaly coefficient as positively correlated is because a larger coefficient indicates a more significant radial runout of the crankshaft. In this case, increasing the clamping force enhances the rigidity and stability of the crankshaft during rotation, suppresses shaft offset, and allows the relative motion between the grinding wheel and the crankshaft to return to the preset trajectory. This achieves adaptive correction of grinding anomalies, ensuring the grinding continuity and machining quality at the oil hole location.

[0127] Specifically, the grinding anomaly coefficient of the connecting surface is the ratio of the average absolute value of the sound intensity difference at all symmetrical positions to a preset sound intensity benchmark value.

[0128] For example, the grinding anomaly coefficient of the mating surface is an index that quantifies the degree of difference in grinding conditions on both sides of the oil hole, and can be calculated and determined in the following way:

[0129] Let n groups of symmetrical locations be selected, and the absolute values ​​of the sound intensity differences corresponding to each group be |ΔV1|, |ΔV2|, ..., |ΔV n |, in dB, the average of the absolute values ​​of the sound intensity differences at all symmetrical locations in the group = (|ΔV1| + |ΔV2| + ... + |ΔV n |) / n;The preset sound intensity benchmark value is the arithmetic mean of the sound intensity of all sampling points;Grinding anomaly coefficient of the joint surface = the average of the absolute values ​​of the sound intensity differences at all symmetrical positions / sound intensity benchmark value.

[0130] Specifically, please refer to Figure 5 The diagram shown is a system block diagram of a crankshaft hard-turning system based on multi-parameter monitoring according to an embodiment of the present invention. The present invention also provides a crankshaft hard-turning system based on multi-parameter monitoring, comprising:

[0131] The grinding assembly includes a clamp for holding the spindles at both ends of the crankshaft and a grinding wheel for grinding the surface of the crankshaft.

[0132] This invention does not specifically limit the result of the fixture. The fixture in this invention is a three-jaw linkage fixture, which is widely used in the grinding process of parts to fix the parts. Further details will not be provided.

[0133] The trajectory filtering module is used to pre-obtain the movement trajectory of the grinding wheel's center point and filter out the trajectory segments where the grinding wheel crosses the oil hole.

[0134] The present invention does not limit the trajectory filtering module, which can be a data storage device connected to the servo motor encoder that controls the movement of the grinding wheel, used to read the movement trajectory of the grinding wheel center point in the servo motor encoder and filter the trajectory segment.

[0135] The acquisition module, which is connected to the trajectory filtering module, includes an acoustic fingerprint acquisition unit for capturing acoustic fingerprint information of the grinding wheel within the trajectory segment and a distance acquisition unit for obtaining the deviation distance value between the center point of the grinding wheel and the center of the oil hole.

[0136] The voiceprint acquisition unit in this invention can be an industrial microphone, and the distance acquisition unit can be a data processor, used to calculate the deviation distance between the two points based on the coordinates of the center point of the grinding wheel and the center of the oil hole.

[0137] A quantization module, which is connected to the acquisition module, is used to construct an intensity curve of the sound intensity of the grinding wheel contacting the crankshaft surface as a function of the position of the center point of the grinding wheel.

[0138] The present invention does not limit the quantification module, which can be an industrial computer, and constructs an intensity curve using the acquired sound intensity data and the deviation distance between the center point of the grinding wheel and the center of the oil hole.

[0139] An anomaly analysis module, which is connected to the quantization module, is used to determine whether there is an anomaly in the grinding continuity of the grinding wheel on the adjacent surface at the oil hole location and to determine the type of grinding continuity anomaly.

[0140] The grinding control module is connected to the anomaly analysis module and the grinding assembly, respectively, and is used to adjust the grinding wheel feed speed for different anomaly categories, or to adjust the clamping force of the clamps at both ends of the crankshaft.

[0141] This invention does not limit the anomaly analysis module and the grinding control module, both of which can be constructed using logic components. The logic components can be field-programmable logic components, microprocessors, processors used in computers, etc., which will not be elaborated here.

[0142] The technical solution of the present invention has been described above with reference to the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the scope of protection of the present invention.

[0143] The above description is merely a preferred embodiment of the present invention and is not intended to limit the 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 crankshaft hard turning method based on multi-parameter monitoring, characterized in that, include: The movement trajectory of the grinding wheel's center point is obtained in advance, and the grinding connection trajectory segment where the grinding wheel crosses the oil hole is selected; The acoustic signature information of the grinding wheel grinding within the grinding connection trajectory segment is captured, and an intensity curve of the sound intensity of the grinding wheel contacting the crankshaft surface as a function of the position of the grinding wheel center point is constructed based on the acoustic signature information. Based on the symmetry analysis of the intensity curve, determine whether there is an abnormality in the grinding continuity of the grinding wheel on the adjacent surfaces at the oil hole location; This includes determining the dividing line using the abscissa of the oil hole center as the boundary, and dividing the intensity curve into a first characteristic curve segment and a second characteristic curve segment; Several sets of symmetrical position points about the boundary line are selected on the first feature curve segment and the second feature curve segment respectively, and the sound intensity value corresponding to each set of symmetrical position points is extracted. Calculate and record the absolute value of the sound intensity difference at each symmetrical location point; The absolute value of the sound intensity difference is compared with a preset intensity difference threshold. If the absolute value of the sound intensity difference between any set of symmetrical positions is less than or equal to the intensity difference threshold, it is determined that there is no abnormality in the grinding continuity of the grinding wheel on the adjacent surface at the oil hole position. If the absolute value of the sound intensity difference at any set of symmetrical positions is greater than the intensity difference threshold, it is determined that the grinding continuity of the grinding wheel on the adjacent surface at the oil hole position is abnormal. In response to an anomaly in the grinding continuity of adjacent surfaces at the oil hole location, the category of the grinding continuity anomaly is determined based on the positional deviation analysis results of the characteristic explicit points on the intensity curve. This includes extracting the x-axis coordinates of the dominant feature points; Calculate the deviation distance between the horizontal axis coordinate of the characteristic visible point and the center coordinate of the oil hole, and compare the deviation distance value with a preset deviation reference value; If the deviation distance value is less than or equal to the deviation reference value, then the grinding continuity abnormality is determined to be the first abnormality category; If the deviation distance value is greater than the deviation reference value, then the grinding continuity abnormality is determined to be the second abnormality category; The characteristic point is the point corresponding to the maximum sound intensity on the intensity curve; For different categories of grinding continuity abnormalities, the adjustment method for crankshaft grinding is determined to be adjusting the feed speed of the grinding wheel in the grinding connection trajectory segment, or adjusting the clamping force of the clamps at both ends of the crankshaft. If the grinding continuity abnormality is the first abnormality category, then the adjustment method for crankshaft grinding is determined to be adjusting the feed speed of the grinding wheel within the grinding connection trajectory segment. If the grinding continuity abnormality is classified as the second abnormality category, then the adjustment method for crankshaft grinding is determined to be adjusting the clamping force of the clamps at both ends of the crankshaft.

2. The crankshaft hard turning method based on multi-parameter monitoring according to claim 1, characterized in that, The process of selecting the grinding trajectory segment where the grinding wheel crosses the oil hole includes: Obtain the 3D model data of the crankshaft and extract the center coordinates and diameter of the oil holes; Establish a crankshaft machining space coordinate system, map the pre-acquired grinding wheel center point movement trajectory into the crankshaft machining space coordinate system, and determine the trajectory segment of the preset length as the grinding connection trajectory segment with the oil hole center coordinate as the midpoint; The preset length is determined based on the aperture size.

3. The crankshaft hard turning method based on multi-parameter monitoring according to claim 2, characterized in that, The process of constructing an intensity curve of sound intensity as a function of the center point position of the grinding wheel includes: Extract the sound intensity parameters corresponding to each sampling time from the voiceprint information; The position coordinates of the grinding wheel center point in the machining space coordinate system are recorded in real time at each sampling moment to determine the distance between the grinding wheel center point and the center coordinates of the oil hole; Plot an intensity curve of sound intensity as the position of the grinding wheel center point, with the distance as the x-axis and the sound intensity parameter as the y-axis.

4. The crankshaft hard turning method based on multi-parameter monitoring according to claim 1, characterized in that, The process of adjusting the feed speed of the grinding wheel and the clamping force of the clamps at both ends of the crankshaft includes: Adjust the feed speed of the grinding wheel in the grinding connection trajectory segment and the clamping force of the clamps at both ends of the crankshaft according to the grinding anomaly coefficient of the connection surface; The feed rate is negatively correlated with the grinding anomaly coefficient of the connecting surface, while the clamping force of the clamps at both ends of the crankshaft is positively correlated with the grinding anomaly coefficient of the connecting surface.

5. The crankshaft hard turning method based on multi-parameter monitoring according to claim 4, characterized in that, The grinding anomaly coefficient of the connecting surface is the ratio of the average absolute value of the sound intensity difference at all symmetrical positions to the preset sound intensity benchmark value.

6. A crankshaft hard turning system based on multi-parameter monitoring, used to execute the crankshaft hard turning method based on multi-parameter monitoring as described in any one of claims 1-5, characterized in that, include: The grinding assembly includes a clamp for holding the spindles at both ends of the crankshaft and a grinding wheel for grinding the surface of the crankshaft. The trajectory filtering module is used to pre-obtain the movement trajectory of the grinding wheel's center point and filter out the trajectory segments where the grinding wheel crosses the oil hole. The acquisition module, which is connected to the trajectory filtering module, includes an acoustic fingerprint acquisition unit for capturing acoustic fingerprint information of the grinding wheel within the trajectory segment and a distance acquisition unit for obtaining the deviation distance value between the center point of the grinding wheel and the center of the oil hole. A quantization module, which is connected to the acquisition module, is used to construct an intensity curve of the sound intensity of the grinding wheel contacting the crankshaft surface as a function of the position of the center point of the grinding wheel. An anomaly analysis module, which is connected to the quantization module, is used to determine whether there is an anomaly in the grinding continuity of the grinding wheel on the adjacent surface at the oil hole location and to determine the type of grinding continuity anomaly. The grinding control module is connected to the anomaly analysis module and the grinding assembly, respectively, and is used to adjust the grinding wheel feed speed for different anomaly categories, or to adjust the clamping force of the clamps at both ends of the crankshaft.

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