Method and system for evaluating uniformity of groove on center pendulum sealing surface based on depth measurement

Abstract

The present invention provides a method and system for evaluating the uniformity of grooves on a sealing surface of a center pendulum based on depth measurement, and relates to the technical field of center pendulum sealing of a micro internal combustion engine. The present invention arranges a plurality of groups of H fractal structures on the sealing surface of the center pendulum, thereby not only significantly improving the sealing performance of the center pendulum, but also does not add any additional components, is more conducive to the long-term operation of the system, and reduces additional material costs. At the same time, the present invention arranges an infrared ranging test to accurately measure the groove depth of the center pendulum, and evaluates the short-term processing uniformity and long-term processing uniformity of the groove depth of the center pendulum during processing by constructing a fluctuation matrix and calculating a fluctuation coefficient, respectively, thereby ensuring the processing quality, optimizing the process parameters, and improving the processing efficiency and economic benefits.

Description

Technical Field

[0001] The present invention relates to the technical field of center pendulum seals for micro internal combustion engines, and in particular to a method and system for evaluating the uniformity of grooves on a center pendulum seal surface based on depth measurement. Background Art

[0002] As one of the micro power devices, the micro pendulum internal combustion engine has a smaller structure size and a smaller combustion chamber volume. Under the same sealing conditions, the mass leakage of the combustion chamber increases rapidly, which makes it difficult to maintain the combustion pressure and even fails to ignite and operate normally, resulting in a significant reduction in the thermal efficiency of the combustion chamber, which makes the thermal efficiency of the micro pendulum internal combustion engine extremely low and the working reliability deteriorates. At present, the radial seal between the center pendulum of the micro pendulum internal combustion engine and the cylinder body of the combustion chamber is usually achieved by smooth gap sealing. When the sealing gap is too large, the mass leakage increases significantly, so that the combustion pressure cannot be guaranteed; when the sealing gap is too small, the center pendulum is easily heated and expands, causing friction, wear and bonding with the cylinder body.

[0003] In the prior art, the publication number CN204284432U discloses a new type of seal at the top of the rotor, including a needle roller seal, a sealing column and a wave spring sheet; the needle roller seal, the sealing column and the wave spring sheet are assembled in sequence from top to bottom; an arc groove is provided axially on the sealing column, and the needle roller seal is placed in the arc groove; a wave spring sheet is provided below the sealing column, and the wave spring sheet is placed in the arc groove of the rotor. Among them, the needle roller seal is a sealing form in which it rolls with the inner wall of the cylinder body of the internal combustion engine, replacing the original sealing form in which the seal slides with the inner wall of the cylinder body of the internal combustion engine. This sealing form undoubtedly increases the number of parts. For the principle of simplifying the structure of micro-mechanical products, adding system parts will bring more difficulties to product assembly and replacement, and the contact seal power consumption loss is large, which is not conducive to the long-term operation of the micro system. In the processing process, the depth uniformity of the arc groove will also affect the sealing effect, but it is also difficult to detect and evaluate during the production process. Therefore, under the action of multiple factors, its applicability is poor, which is not conducive to large-scale promotion.

[0004] The above information disclosed in this Background section is only for enhancement of understanding of the background of the present disclosure and therefore it may contain information that does not constitute the prior art that is already known to one of ordinary skill in the art. Summary of the invention

[0005] The object of the present invention is to provide a method and system for evaluating the uniformity of a groove on a center pendulum sealing surface based on depth measurement, so as to solve the problems raised in the above-mentioned background technology.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] A method for evaluating the uniformity of grooves on a center pendulum sealing surface based on depth measurement, the specific steps comprising:

[0008] S1: collecting the dimension data of the center pendulum, evenly setting the H fractal structure on the sealing surface of the center pendulum according to the dimension data of the center pendulum and performing trial processing, wherein the sealing surface of the center pendulum is a curved surface, and the H fractal structure is set on the sealing surface of the center pendulum in a groove structure;

[0009] S2: After the trial processing, the center pendulum is subjected to infrared ranging tests in the circumferential and axial directions respectively, and the groove depths of the H-fractal structure in the axial and circumferential directions are collected respectively. The corresponding groove depth variation curves are generated according to the groove depths in the two directions, and the groove depth variation curves are image-superimposed to obtain the circumferential depth data and the axial depth data based on the threshold judgment method;

[0010] S3: Evaluate the short-term machining uniformity of the center pendulum groove depth according to the circumferential fluctuation matrix and the axial fluctuation matrix, adjust the process parameters of the trial machining, and repeat steps S1 to S2 until the short-term machining uniformity of the center pendulum is qualified;

[0011] S4: Continuously perform H-fractal structure trial processing on at least three center pendulums, and evaluate the long-term processing uniformity based on the short-term processing uniformity of each center pendulum, and generate a recommended continuous processing number based on the long-term processing uniformity.

[0012] Preferably, the dimensional data of the center pendulum includes thickness D, outer diameter R, and arc length L of the sealing section, and the H fractal structure includes first-order H fractal, second-order H fractal, third-order H fractal, and fourth-order H fractal.

[0013] Preferably, the first-order H fractal, second-order H fractal, third-order H fractal and fourth-order H fractal are evenly distributed on the sealing surface of the center pendulum, the second-order H fractal is arranged between the four first-order H fractals, the third-order H fractal is arranged between the four second-order H fractals, the fourth-order H fractal is arranged between the four third-order H fractals, and the groove width d and groove depth h of the first-order H fractal, second-order H fractal, third-order H fractal and fourth-order H fractal are equal.

[0014] Preferably, the infrared distance measurement test is performed using an infrared distance meter, and the specific method is as follows:

[0015] S201: Taking the H fractal structure located at the upper left of the central pendulum sealing surface as a reference, the intersection of the transverse symmetry axis of the H fractal structure and the left boundary of the sealing surface is taken as the first distance measurement starting point, the test direction of the infrared rangefinder is vertically downward, and the line between the central pendulum axis and the first distance measurement starting point is vertically upward;

[0016] S202: The infrared rangefinder rotates clockwise at a preset rotation angle, remains stationary for 3 seconds after the rotation is completed, and then rotates in the opposite direction at the same speed at the same rotation angle to obtain a groove depth variation curve of a row of H fractal structures in the circumferential direction, and obtains corresponding circumferential depth data according to the groove depth variation curve of the row of H fractal structures in the circumferential direction;

[0017] S203: Counting the number of executions of step S202, making the infrared rangefinder move along the axial direction at a preset interval, repeatedly executing step S202 and updating the number of executions of step S202, obtaining the circumferential depth data of all H-fractal structures, and when the number of executions of step S202 is equal to the number of rows of the H-fractal structure, the execution is considered to be completed, and the infrared rangefinder returns to the initial position;

[0018] S204: Taking the H-fractal structure located at the upper left of the central pendulum sealing surface as a reference, the intersection of the left bottom midline of the H-fractal structure and the upper boundary of the sealing surface is used as the second distance measurement starting point, the test direction of the infrared rangefinder is vertically downward, and the line between the central pendulum axis and the second distance measurement starting point is vertically upward;

[0019] S205: the infrared rangefinder moves a preset moving distance at a uniform speed along the axial direction, the moving distance being the same as the thickness of the central pendulum, and stops for 3 seconds after the moving is completed, and moves the same moving distance at a uniform speed in the reverse direction at the same speed to obtain a series of groove depth variation curves of the H fractal structure in the axial direction, and obtains corresponding axial depth data according to the series of groove depth variation curves of the H fractal structure in the axial direction;

[0020] S206: Count the number of executions of step S205, and according to the number of executions, make the infrared rangefinder select a corresponding and preset interval angle for rotation, repeatedly execute step S205 and update the number of executions of step S205, and obtain the axial depth data of all H fractal structures. When the number of executions of step S205 is equal to twice the number of columns of the H fractal structure, the execution is considered to be completed, and the infrared rangefinder returns to the initial position.

[0021] Preferably, the axial length of the H fractal structure is calibrated as l i , the circumferential length is marked as w i , the axial spacing is calibrated as σ1 i , the circumferential spacing is calibrated as σ2 i , the subscript i represents the order of the H fractal structure, i = 1, 2, 3, 4, and the rotation angle is expressed in radians and is denoted by θ z , and θ z =L / R, the interval distance is calibrated as δ g , v g = l i +σ1 i , the moving distance is calibrated as δ y , δ y =D;

[0022] The interval angles are expressed in radians, including the first interval angle θ1 g and the second interval angle θ2 g When the number of executions of step S205 is an odd number, in step S206, the infrared range finder selects the first interval angle θ1 g When the number of executions of step S205 is an even number, in step S206, the infrared rangefinder selects the second interval angle θ2 g Rotate, where θ1 g =(w i -d) / R,θ2 g =(σ2 i +d) / R.

[0023] Preferably, the method for generating the circumferential fluctuation coefficient and the axial fluctuation coefficient of all H fractal structures is:

[0024] Generate judgment threshold d based on the groove depth of H fractal structure yz and fluctuation range d bd , judgment threshold d yz =k1d, fluctuation range d bd =[-k2d,k2d], where k1 and k2 represent the first fluctuation coefficient and the second fluctuation coefficient respectively, and 1>k2>k1>0;

[0025] Three parallel lines are generated according to the judgment threshold and the upper and lower limits of the fluctuation range, and are superimposed with the groove depth variation curves of the center pendulum in the circumferential and axial directions. The part of the groove depth variation curve located above the judgment threshold is defined as several valid value segments, and the valid value segments of the groove depth variation curve are analyzed;

[0026] When analyzing the groove depth variation curve of the center pendulum in the circumferential direction, each effective value segment of the groove depth variation curve corresponds to the H fractal structure one by one. The total area of ​​the graph formed by each effective value segment and the judgment threshold, and the effective area of ​​the graph where the effective value segment is located between the upper and lower limits of the fluctuation range are counted. The ratio of the effective area to the total area is defined as the circumferential fluctuation coefficient and is calibrated as Where superscript j represents the number of the center pendulum of the continuous trial processing, j = 1, 2, 3, ..., J, (x, y) represents the H fractal structure corresponding to the xth column and yth row, x = 1, 2, 3, ..., M, y = 1, 2, 3, ..., N;

[0027] When analyzing the groove depth variation curve of the center pendulum in the axial direction, all the groove depth variation curves of the center pendulum in the axial direction are grouped in pairs in turn according to the number of executions of step S205, and each group of groove depth variation curves is analyzed respectively. In each group of groove depth variation curves, each effective value segment of the groove depth variation curve with an odd number of executions corresponds one-to-one to the left side of each H fractal structure, and each effective value segment of the groove depth variation curve with an even number of executions corresponds one-to-one to the right side of each H fractal structure. The ratio of the effective area of ​​the effective value segment to the total area in each group of groove depth variation curves is calculated respectively, and then the average is taken and defined as the axial fluctuation coefficient, and calibrated as

[0028] Preferably, the circumferential fluctuation matrix It is expressed as:

[0029]

[0030] Axial Fluctuation Matrix It is expressed as:

[0031]

[0032] Calculate the standard deviation of the circumferential fluctuation matrix and the axial fluctuation matrix respectively and When satisfied and Both are smaller than S y When S y Indicates the preset short-term threshold.

[0033] Preferably, the standard deviation of the circumferential fluctuation matrix and the axial fluctuation matrix of the central pendulum numbered 1 to p is and Divide into sets B1 p and B2 p , p∈[3,J], and p is an integer;

[0034] Calculate the set B1 separately p and B2 p The standard deviation S1 i ′ and S2 i ′, and S1 i ′、S2 i ′ is compared with the preset long-term threshold interval, and all values ​​of p are traversed to obtain all values ​​that satisfy S1 i ′,S2 i ′∈[-S y ′,S y ′], and the largest p value is considered as the recommended continuous processing number, where -S y ′、S y′ represent the lower and upper limits of the long-term threshold interval, respectively.

[0035] The present invention further provides a center pendulum sealing surface groove uniformity evaluation system based on depth measurement, the evaluation system is used to perform the above evaluation method, including:

[0036] A data acquisition module, which is electrically connected to the data analysis module and is used to collect the size data of the center pendulum;

[0037] A processing module, the processing module is electrically connected to the data analysis module, and is used to process the sealing surface of the center pendulum according to the process parameters preset by the user to generate an H fractal structure;

[0038] A distance measurement module, which includes a measuring unit and a driving unit, both of which are electrically connected to the data analysis module, and is used to perform an infrared distance measurement test on the center pendulum, measure the depth change of the sealing surface of the center pendulum, and obtain corresponding circumferential and axial groove depth change curves;

[0039] A data analysis module, the data analysis module is electrically connected to the comprehensive processing module, and is used to generate a motion trajectory of the infrared rangefinder during the infrared rangefinder test according to the size data of the center pendulum and the process parameters of the H-fractal structure and send the trajectory to the driving unit of the rangefinder module, and is also used to construct a circumferential fluctuation matrix and an axial fluctuation matrix and evaluate the short-term processing uniformity of the center pendulum groove depth;

[0040] A comprehensive processing module, the comprehensive processing module is used to evaluate the long-term processing uniformity according to the short-term processing uniformity of the center pendulum groove depth, and generate a recommended continuous processing number according to the long-term processing uniformity.

[0041] Compared with the prior art, the present invention has the following beneficial effects:

[0042] The present invention arranges several groups of H fractal structures on the sealing surface of the center pendulum, which not only significantly improves the sealing performance of the center pendulum, but also does not add additional parts, is more conducive to the long-term operation of the system, and reduces additional material costs. At the same time, the present invention arranges an infrared ranging test to accurately measure the groove depth of the center pendulum, and evaluates the short-term processing uniformity and long-term processing uniformity of the groove depth of the center pendulum during the processing by constructing a fluctuation matrix and calculating the fluctuation coefficient. Not only does it ensure the processing quality, but it also optimizes the process parameters and improves the processing efficiency and economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 It is a schematic diagram of the overall method flow of the present invention;

[0044] Figure 2 It is a schematic diagram of the central pendulum with an H-fractal structure according to the present invention;

[0045] Figure 3 It is a top view of the central pendulum sealing surface of the present invention;

[0046] Figure 4 It is a schematic diagram of the connection between the center pendulum and the cylinder block of the internal combustion engine in the prior art;

[0047] Figure 5 It is a schematic diagram of the connection between the center pendulum and the cylinder block of the internal combustion engine of the present invention;

[0048] Figure 6 It is a schematic diagram of the module structure of the present invention.

[0049] In the figure: 10, the center pendulum in the present invention; 11, the first order H fractal; 12, the second order H fractal; 13, the third order H fractal; 14, the fourth order H fractal; 20, the cylinder block of the internal combustion engine; 30, the center pendulum in the prior art. DETAILED DESCRIPTION

[0050] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments.

[0051] It should be noted that, unless otherwise defined, the technical terms or scientific terms used in the present invention should be understood by people with ordinary skills in the field to which the present invention belongs. The words "first", "second" and similar words used in the present invention do not indicate any order, quantity or importance, but are only used to distinguish different components. "Include" or "comprise" and similar words mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Connect" or "connected" and similar words are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0052] Example:

[0053] See also Figure 1-Figure 5 , the present invention provides a technical solution:

[0054] A method for evaluating the uniformity of grooves on a center pendulum sealing surface based on depth measurement, the specific steps comprising:

[0055] S1: collecting the dimension data of the center pendulum, evenly setting the H fractal structure on the sealing surface of the center pendulum according to the dimension data of the center pendulum and performing trial processing, wherein the sealing surface of the center pendulum is a curved surface, and the H fractal structure is set on the sealing surface of the center pendulum in a groove structure;

[0056] The dimension data of the center pendulum include thickness D, outer diameter R, and arc length L of the sealing section. The H-fractal structure includes first-order H-fractal, second-order H-fractal, third-order H-fractal, and fourth-order H-fractal. The first-order H-fractal, second-order H-fractal, third-order H-fractal, and fourth-order H-fractal are evenly distributed on the sealing surface of the center pendulum. The second-order H-fractal is arranged between four first-order H-fractals, the third-order H-fractal is arranged between four second-order H-fractals, and the fourth-order H-fractal is arranged between four third-order H-fractals. The groove width d and groove depth h of the first-order H-fractal, second-order H-fractal, third-order H-fractal, and fourth-order H-fractal are all equal.

[0057] In this step, the purpose of setting the H-fractal mechanism is to utilize the turbulence effect to improve the sealing performance of the center pendulum sealing surface. Compared with the needle-type seal in the prior art, the sealing form in which the needle-type seal rolls with the inner wall of the internal combustion engine cylinder body replaces the sealing form in which the original seal and the inner wall of the internal combustion engine cylinder body slide against each other. The present invention switches back to the sealing form in which the sealing surface and the inner wall of the internal combustion engine cylinder body slide against each other, and sets the H-fractal mechanism. A smaller gap can be set between the sealing surface and the inner wall of the internal combustion engine cylinder body. There is no need to worry about the center pendulum expanding due to heat and causing friction, wear and bonding with the inner wall of the cylinder body, nor is there any need to worry about a larger gap causing increased mass leakage and a greater reduction in combustion pressure. Therefore, on the basis of improving the sealing effect, no additional components are added, which is more conducive to the long-term operation of the system and reduces additional material costs. By simulating and modeling the center pendulum without H-fractal structure and the center pendulum with H-fractal structure respectively, the fluid area between the left combustion chamber and the corresponding exhaust port of the two center pendulums was extracted using Spacec laim software, and then pressure section monitoring was established at the central section of the fluid area. Finally, after calculation and solution using Fluent software, it was concluded that the central section pressure of the fluid area of ​​the center pendulum without H-fractal structure was 548160.76 Pa, while the central section pressure of the fluid area of ​​the center pendulum with H-fractal structure was 383450.3 Pa, which effectively reduced by 164710.46 Pa, much higher than the current mainstream maze structure or honeycomb structure (these two reduce up to 100000 Pa), thus proving the effectiveness of the H-fractal structure.

[0058] In this embodiment, assuming that the number of first-order H fractals is 8*8, then correspondingly, the number of second-order H fractals is 4*4, the number of third-order H fractals is 2*2, and the number of fourth-order H fractals is 1.

[0059] S2: After the trial processing, the center pendulum is subjected to infrared ranging tests in the circumferential and axial directions respectively, and the groove depths of the H-fractal structure in the axial and circumferential directions are obtained respectively. The corresponding groove depth variation curves are generated according to the groove depths in the two directions, and the groove depth variation curves are image-superimposed to obtain the circumferential depth data and the axial depth data based on the threshold judgment method.

[0060] The infrared distance measurement test is carried out using an infrared distance meter. The specific method is as follows:

[0061] S201: Taking the H fractal structure located at the upper left of the central pendulum sealing surface as a reference, the intersection of the transverse symmetry axis of the H fractal structure and the left boundary of the sealing surface is taken as the first distance measurement starting point, the test direction of the infrared rangefinder is vertically downward, and the line between the central pendulum axis and the first distance measurement starting point is vertically upward;

[0062] S202: The infrared rangefinder rotates clockwise at a preset rotation angle, remains stationary for 3 seconds after the rotation is completed, and then rotates in the opposite direction at the same speed at the same rotation angle to obtain a groove depth variation curve of a row of H fractal structures in the circumferential direction, and obtains corresponding circumferential depth data according to the groove depth variation curve of the row of H fractal structures in the circumferential direction;

[0063] S203: Counting the number of executions of step S202, making the infrared rangefinder move along the axial direction at a preset interval, repeatedly executing step S202 and updating the number of executions of step S202, obtaining the circumferential depth data of all H-fractal structures, and when the number of executions of step S202 is equal to the number of rows of the H-fractal structure, the execution is considered to be completed, and the infrared rangefinder returns to the initial position;

[0064] S204: Taking the H-fractal structure located at the upper left of the central pendulum sealing surface as a reference, the intersection of the left bottom midline of the H-fractal structure and the upper boundary of the sealing surface is used as the second distance measurement starting point, the test direction of the infrared rangefinder is vertically downward, and the line between the central pendulum axis and the second distance measurement starting point is vertically upward;

[0065] S205: the infrared rangefinder moves a preset moving distance at a uniform speed along the axial direction, the moving distance being the same as the thickness of the central pendulum, and stops for 3 seconds after the moving is completed, and moves the same moving distance at a uniform speed in the reverse direction at the same speed to obtain a series of groove depth variation curves of the H fractal structure in the axial direction, and obtains corresponding axial depth data according to the series of groove depth variation curves of the H fractal structure in the axial direction;

[0066] S206: Count the number of executions of step S205, and according to the number of executions, make the infrared rangefinder select a corresponding and preset interval angle for rotation, repeatedly execute step S205 and update the number of executions of step S205, and obtain the axial depth data of all H fractal structures. When the number of executions of step S205 is equal to twice the number of columns of the H fractal structure, the execution is considered to be completed, and the infrared rangefinder returns to the initial position.

[0067] In the infrared ranging test, since the H fractal structures are evenly and centrally arrayed on the sealing surface of the central pendulum, that is, on the premise of equal orders, the spacing between adjacent two columns of H fractal structures is equal, the spacing between adjacent two rows of H fractal structures is also equal, the spacing between the uppermost row of H fractal structures and the upper and lower edges of the sealing surface is equal, and the spacing between the leftmost row of H fractal structures and the left and right edges of the sealing surface is also equal. Moreover, these spacing parameters are all controlled by the process parameters preset by the user. Therefore, the horizontal axis of symmetry and the left bottom center line of the H fractal structures can be obtained through the process parameters. At the same time, it can be understood that for the H analysis structure, only the depth of the middle "-" needs to be detected in the horizontal direction, but the depths of the two sides "|" need to be detected separately in the vertical direction. Therefore, in step S202, after the central pendulum rotates a certain angle, the infrared rangefinder can detect the depths of the middle parts of a row of H fractal structures. In step S205, after the central pendulum moves axially a certain distance, the infrared rangefinder can only detect one side of a column of H fractal structures. When step S205 is executed for the first time, the left side of the leftmost first column of H fractal structures is detected. When step S205 is executed for the second time, the right side of the leftmost first column of H fractal structures is detected. And so on. When step S205 is executed for the (2k - 1)th time, the left side of the kth column of H fractal structures from the left is detected. When step S205 is executed for the 2kth time, the right side of the kth column of H fractal structures from the left is detected. At the same time, the axial movement or circumferential rotation of the infrared rangefinder can be achieved by the method of being fixed on the shaft and driven by a motor, or by the method of being fixed on the machine tool and controlled by a PLC. The implementation means are diverse and all belong to the existing technologies, so no limitation is made.

[0068] Define the axial length of the H fractal structure as l i , and the circumferential length as w i , the axial interval as σ1 i , and the circumferential interval as σ2 i . Let the subscript i represent the order of the H fractal structure, i = 1, 2, 3, 4. The rotation angle is represented in radians and is defined as θ z , and θ z = L / R. Define the interval distance as δ g , δ g = l i + σ1 i . Define the moving distance as δ y , δ y = D;

[0069] The interval angle is represented in radians, including the first interval angle θ1 g and the second interval angle θ2 gWhen the number of executions of step S205 is an odd number, in step S206, the infrared rangefinder selects the first interval angle θ1 g When the number of executions of step S205 is an even number, in step S206, the infrared rangefinder selects the second interval angle θ2 g Rotate, where θ1 g =(w i -d) / R,θ2 g =(σ2 i +d) / R.

[0070] The method for generating the circumferential fluctuation coefficient and axial fluctuation coefficient of all H fractal structures is:

[0071] Generate judgment threshold d based on the groove depth of H fractal structure yz and fluctuation range d bd , judgment threshold d yz =k1d, fluctuation range d bd =[-k2d,k2d], where k1 and k2 represent the first and second fluctuation coefficients respectively. Considering that the inner wall of the H fractal structure may have a certain draft angle during processing, or there may be fine dust residue on both sides of the inner wall edge, the depth may be smaller than that of the middle part. Therefore, the first fluctuation coefficient is taken as smaller, 1>k2>k1>0;

[0072] Three parallel lines are generated according to the judgment threshold and the upper and lower limits of the fluctuation range, and are superimposed with the groove depth variation curves of the center pendulum in the circumferential and axial directions. The part of the groove depth variation curve located above the judgment threshold is defined as several valid value segments, and the valid value segments of the groove depth variation curve are analyzed;

[0073] When analyzing the groove depth variation curve of the center pendulum in the circumferential direction, each effective value segment of the groove depth variation curve corresponds to the H fractal structure one by one. The total area of ​​the graph formed by each effective value segment and the judgment threshold, and the effective area of ​​the graph where the effective value segment is located between the upper and lower limits of the fluctuation range are counted. The ratio of the effective area to the total area is defined as the circumferential fluctuation coefficient and is calibrated as Where superscript j represents the number of the center pendulum of the continuous trial processing, j = 1, 2, 3, ..., J, (x, y) represents the H fractal structure corresponding to the xth column and yth row, x = 1, 2, 3, ..., M, y = 1, 2, 3, ..., N;

[0074] When analyzing the groove depth variation curve of the center pendulum in the axial direction, all the groove depth variation curves of the center pendulum in the axial direction are grouped in pairs in turn according to the number of executions of step S205, and each group of groove depth variation curves is analyzed respectively. In each group of groove depth variation curves, each effective value segment of the groove depth variation curve with an odd number of executions corresponds one-to-one to the left side of each H fractal structure, and each effective value segment of the groove depth variation curve with an even number of executions corresponds one-to-one to the right side of each H fractal structure. The ratio of the effective area of ​​the effective value segment to the total area in each group of groove depth variation curves is calculated respectively, and then the average is taken and defined as the axial fluctuation coefficient, and calibrated as

[0075] When analyzing the groove depth variation curve, the sealing surface of the center pendulum is used as a reference. When the detection beam of the infrared rangefinder enters the downward concave H-fractal structure from the sealing surface, the groove depth variation curve will produce a corresponding rising area, that is, the effective value segment. When leaving the H-fractal structure and returning to the sealing surface, the rising area ends. The fluctuation of the groove depth variation curve in the effective value segment also reflects the depth uniformity of the groove of the H-fractal structure. In other words, the larger the ratio of the effective area to the total area of ​​the effective value segment, the more uniform the groove depth of the corresponding H-fractal structure.

[0076] Circumferential Fluctuation Matrix It is expressed as:

[0077]

[0078] Axial Fluctuation Matrix It is expressed as:

[0079]

[0080] S3: Evaluate the short-term machining uniformity of the center pendulum groove depth according to the circumferential fluctuation matrix and the axial fluctuation matrix, adjust the process parameters of the trial machining, and repeat steps S1 to S2 until the short-term machining uniformity of the center pendulum is qualified.

[0081] Calculate the standard deviation of the circumferential fluctuation matrix and the axial fluctuation matrix respectively and When satisfied and Both are smaller than S y When S y Indicates the preset short-term threshold.

[0082] Here the standard deviation of the circumferential fluctuation matrix and the axial fluctuation matrix and That is to say, it shows the degree of discreteness of the groove depth uniformity of all H-fractal structures on the center pendulum sealing surface in the axial direction and in the axial direction. The lower the discreteness, the better the groove depth uniformity, which means that the groove depth of the H-fractal structure on the center pendulum sealing surface is basically consistent during the processing. Conversely, the higher the discreteness, the worse the groove depth uniformity, which means that the groove depth of the H-fractal structure on the center pendulum sealing surface has a large change during the processing.

[0083] S4: Continuously perform H-fractal structure trial processing on at least three center pendulums, and evaluate the long-term processing uniformity based on the short-term processing uniformity of each center pendulum, and generate a recommended continuous processing number based on the long-term processing uniformity.

[0084] The standard deviation of the circumferential fluctuation matrix and the axial fluctuation matrix of the central pendulum numbered 1 to p is and Divide into sets B1 p and B2 p , p∈[3,J], and p is an integer;

[0085] Calculate the set B1 separately p and B2 p The standard deviation S1 i ′ and S2 i ′, and S1 i ′、S2 i ′ is compared with the preset long-term threshold interval, and all values ​​of p are traversed to obtain all values ​​that satisfy S1 i ′,S2 i ′∈[-S y ′,S y ′], and the largest p value is considered as the recommended continuous processing number, where -S y ′、S y ′ represent the lower and upper limits of the long-term threshold interval, respectively.

[0086] In this step, the standard deviation of the circumferential and axial fluctuation matrices is and They represent the uniformity of the groove depth of the H fractal structure on the sealing surface of a single central pendulum, and the set B1 p and B2 p The standard deviation S1 i ′ and S2 i ′, it represents the uniformity of the overall groove depth of the p center pendulums processed continuously. When the uniformity of the overall groove depth meets the requirements, the largest p value is selected as the recommended continuous processing number to improve the processing efficiency while meeting the processing accuracy, thereby reducing the processing cycle and improving the economic benefits.

[0087] See also Figure 6The present invention further provides a center pendulum sealing surface groove uniformity evaluation system based on depth measurement, the evaluation system is used to perform the above evaluation method, including:

[0088] A data acquisition module, which is electrically connected to the data analysis module and is used to collect the size data of the center pendulum;

[0089] A processing module, the processing module is electrically connected to the data analysis module, and is used to process the sealing surface of the center pendulum according to the process parameters preset by the user to generate an H fractal structure;

[0090] A distance measurement module, which includes a measuring unit and a driving unit, both of which are electrically connected to the data analysis module, and is used to perform an infrared distance measurement test on the center pendulum, measure the depth change of the sealing surface of the center pendulum, and obtain corresponding circumferential and axial groove depth change curves;

[0091] A data analysis module, the data analysis module is electrically connected to the comprehensive processing module, and is used to generate a motion trajectory of the center pendulum during the infrared ranging test according to the size data of the center pendulum and the process parameters of the H-fractal structure, and send the trajectory to the driving unit of the ranging module, construct a circumferential fluctuation matrix and an axial fluctuation matrix, and evaluate the short-term processing uniformity of the center pendulum groove depth;

[0092] A comprehensive processing module is used to evaluate the long-term processing uniformity according to the short-term processing uniformity of the center pendulum groove depth, and generate a recommended continuous processing number according to the long-term processing uniformity.

[0093] The above formulas are all dimensionless and numerical calculations. The formula is a formula for the most recent real situation obtained by collecting a large amount of data and performing software simulation. The preset parameters in the formula are set by technicians in this field according to actual conditions.

[0094] The above embodiments may be implemented in whole or in part by software, hardware, firmware or any other combination thereof. When implemented by software, the above embodiments may be implemented in whole or in part in the form of a computer program product. Those skilled in the art may appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein may be implemented by electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed by hardware or software methods depends on the specific application and design constraints of the technical solution.

[0095] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, and may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0096] The above description is only a specific implementation manner of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application.

Claims

1. A method for evaluating the uniformity of grooves on a central pendulum sealing surface based on depth measurement, characterized in that: The specific steps include: S1: collecting the dimension data of the center pendulum, evenly setting the H fractal structure on the sealing surface of the center pendulum according to the dimension data of the center pendulum and performing trial processing, wherein the sealing surface of the center pendulum is a curved surface, and the H fractal structure is set on the sealing surface of the center pendulum in a groove structure; The size data of the central pendulum includes thickness D, outer diameter R, and arc length L of the sealing section, and the H fractal structure includes first-order H fractal, second-order H fractal, third-order H fractal, and fourth-order H fractal; The first-order H fractal, the second-order H fractal, the third-order H fractal, and the fourth-order H fractal are uniformly distributed on the sealing surface of the central pendulum, the second-order H fractal is arranged between the four first-order H fractals, the third-order H fractal is arranged between the four second-order H fractals, and the fourth-order H fractal is arranged between the four third-order H fractals, and the groove width d and the groove depth h of the first-order H fractal, the second-order H fractal, the third-order H fractal, and the fourth-order H fractal are all equal; S2: After the trial processing, the center pendulum is subjected to infrared ranging tests in the circumferential and axial directions respectively, and the groove depths of the H-fractal structure in the axial and circumferential directions are collected respectively. The corresponding groove depth variation curves are generated according to the groove depths in the two directions, and the groove depth variation curves are image-superimposed to obtain the circumferential depth data and the axial depth data based on the threshold judgment method; S3: Generate circumferential fluctuation coefficient and axial fluctuation coefficient according to circumferential depth data and axial depth data, and construct corresponding circumferential fluctuation matrix and axial fluctuation matrix, then evaluate the short-term machining uniformity of the center pendulum groove depth according to the circumferential fluctuation matrix and axial fluctuation matrix, adjust the process parameters of the trial machining, and repeat steps S1 to S2 until the short-term machining uniformity of the center pendulum is qualified; The method for generating the circumferential fluctuation coefficient and axial fluctuation coefficient of all H fractal structures is: Generate judgment threshold d based on the groove depth of H fractal structure yz and fluctuation range d bd , judgment threshold d yz =k1d, fluctuation range d bd =[-k2d,k2d], where k1 and k2 represent the first fluctuation coefficient and the second fluctuation coefficient respectively, and 1>k2>k1>0; Three parallel lines are generated according to the judgment threshold and the upper and lower limits of the fluctuation range, and are superimposed with the groove depth variation curves of the center pendulum in the circumferential and axial directions. The part of the groove depth variation curve located above the judgment threshold is defined as several valid value segments, and the valid value segments of the groove depth variation curve are analyzed; When analyzing the groove depth variation curve of the center pendulum in the circumferential direction, each effective value segment of the groove depth variation curve corresponds to the H fractal structure one by one. The total area of ​​the graph formed by each effective value segment and the judgment threshold, and the effective area of ​​the graph where the effective value segment is located between the upper and lower limits of the fluctuation range are counted. The ratio of the effective area to the total area is defined as the circumferential fluctuation coefficient and is calibrated as Where superscript j represents the number of the center pendulum of the continuous trial processing, j = 1, 2, 3, ..., J, (x, y) represents the H fractal structure corresponding to the xth column and yth row, x = 1, 2, 3, ..., M, y = 1, 2, 3, ..., N; When analyzing the groove depth variation curve of the center pendulum in the axial direction, all the groove depth variation curves of the center pendulum in the axial direction are grouped in pairs in turn, and each group of groove depth variation curves is analyzed separately. In each group of groove depth variation curves, each effective value segment of the groove depth variation curve with an odd number of executions corresponds one-to-one to the left side of each H fractal structure, and each effective value segment of the groove depth variation curve with an even number of executions corresponds one-to-one to the right side of each H fractal structure. The ratio of the effective area of ​​the effective value segment to the total area in each group of groove depth variation curves is calculated respectively, and then the average is taken and defined as the axial fluctuation coefficient, and calibrated as S4: Continuously perform H-fractal structure trial processing on at least three center pendulums, and evaluate the long-term processing uniformity based on the short-term processing uniformity of each center pendulum, and generate a recommended continuous processing number based on the long-term processing uniformity.

2. The method for evaluating the uniformity of the groove of the center pendulum sealing surface based on depth measurement according to claim 1 is characterized in that: The infrared distance measurement test is carried out using an infrared distance meter. The specific method is as follows: S201: Taking the H fractal structure located at the upper left of the central pendulum sealing surface as a reference, the intersection of the transverse symmetry axis of the H fractal structure and the left boundary of the sealing surface is taken as the first distance measurement starting point, the test direction of the infrared rangefinder is vertically downward, and the line between the central pendulum axis and the first distance measurement starting point is vertically upward; S202: The infrared rangefinder rotates clockwise at a preset rotation angle, remains stationary for 3 seconds after the rotation is completed, and then rotates in the opposite direction at the same speed at the same rotation angle to obtain a groove depth variation curve of a row of H fractal structures in the circumferential direction, and obtains corresponding circumferential depth data according to the groove depth variation curve of the row of H fractal structures in the circumferential direction; S203: Counting the number of executions of step S202, making the infrared rangefinder move along the axial direction at a preset interval, repeatedly executing step S202 and updating the number of executions of step S202, obtaining the circumferential depth data of all H-fractal structures, and when the number of executions of step S202 is equal to the number of rows of the H-fractal structure, the execution is considered to be completed, and the infrared rangefinder returns to the initial position; S204: Taking the H-fractal structure located at the upper left of the central pendulum sealing surface as a reference, the intersection of the left bottom midline of the H-fractal structure and the upper boundary of the sealing surface is used as the second distance measurement starting point, the test direction of the infrared rangefinder is vertically downward, and the line between the central pendulum axis and the second distance measurement starting point is vertically upward; S205: the infrared rangefinder moves a preset moving distance at a uniform speed along the axial direction, the moving distance being the same as the thickness of the central pendulum, and stops for 3 seconds after the moving is completed, and moves the same moving distance at a uniform speed in the reverse direction at the same speed to obtain a series of groove depth variation curves of the H fractal structure in the axial direction, and obtains corresponding axial depth data according to the series of groove depth variation curves of the H fractal structure in the axial direction; S206: Count the number of executions of step S205, and according to the number of executions, make the infrared rangefinder select a corresponding and preset interval angle for rotation, repeatedly execute step S205 and update the number of executions of step S205, and obtain the axial depth data of all H fractal structures. When the number of executions of step S205 is equal to twice the number of columns of the H fractal structure, the execution is considered to be completed, and the infrared rangefinder returns to the initial position.

3. The method for evaluating the uniformity of the groove of the center pendulum sealing surface based on depth measurement according to claim 2 is characterized in that: The axial length of the H fractal structure is calibrated as l i , the circumferential length is marked as w i , the axial spacing is calibrated as σ1 i , the circumferential spacing is calibrated as σ2 i , the subscript i represents the order of the H fractal structure, i = 1, 2, 3, 4, and the rotation angle is expressed in radians and is calibrated as θ z , and θ z =L / R, the interval distance is calibrated as δ g , δ g = l i +σ1 i , the moving distance is calibrated as δ y , δ y =D; The interval angles are expressed in radians, including the first interval angle θ1 g and the second interval angle θ2 g When the number of executions of step S205 is an odd number, in step S206, the infrared rangefinder selects the first interval angle θ1 g When the number of executions of step S205 is an even number, in step S206, the infrared rangefinder selects the second interval angle θ2 g Rotate, where θ1 g =(w i -d) / R,θ2 g =(σ2 i +d) / R.

4. The method for evaluating the uniformity of the groove of the center pendulum sealing surface based on depth measurement according to claim 2 is characterized in that: Circumferential Fluctuation Matrix It is expressed as: Axial Fluctuation Matrix It is expressed as: Calculate the standard deviation of the circumferential fluctuation matrix and the axial fluctuation matrix respectively and When satisfied and Both are smaller than S y When S y Indicates the preset short-term threshold.

5. The method for evaluating the uniformity of the groove of the center pendulum sealing surface based on depth measurement according to claim 4 is characterized in that: The standard deviation of the circumferential fluctuation matrix and the axial fluctuation matrix of the central pendulum numbered 1 to p is and Divide into sets B1 p and B2 p , p∈[3,J], and p is an integer; Calculate the set B1 separately p and B2 p The standard deviation S1 i ′ and S2 i ′, and S1 i ′、S2 i ′ is compared with the preset long-term threshold interval, and all values ​​of p are traversed to obtain all values ​​that satisfy S1 i ′,S2 i ′∈[-S y ′,S y ′], and the largest p value is considered as the recommended continuous processing number, where -S y ′、S y ′ represent the lower and upper limits of the long-term threshold interval, respectively.

6. A center pendulum seal surface groove uniformity evaluation system based on depth measurement, characterized in that: The evaluation system is used to execute the evaluation method according to any one of claims 1 to 5, comprising: A data acquisition module, which is electrically connected to the data analysis module and is used to collect the size data of the center pendulum; A processing module, the processing module is electrically connected to the data analysis module, and is used to process the sealing surface of the center pendulum according to the process parameters preset by the user to generate an H fractal structure; A distance measurement module, which includes a measuring unit and a driving unit, both of which are electrically connected to the data analysis module, and is used to perform an infrared distance measurement test on the center pendulum, measure the depth change of the sealing surface of the center pendulum, and obtain corresponding circumferential and axial groove depth change curves; A data analysis module, the data analysis module is electrically connected to the comprehensive processing module, and is used to generate a motion trajectory of the infrared rangefinder during the infrared rangefinder test according to the size data of the center pendulum and the process parameters of the H-fractal structure and send the trajectory to the driving unit of the rangefinder module, and is also used to construct a circumferential fluctuation matrix and an axial fluctuation matrix and evaluate the short-term processing uniformity of the center pendulum groove depth; A comprehensive processing module is used to evaluate the long-term processing uniformity according to the short-term processing uniformity of the center pendulum groove depth, and generate a recommended continuous processing number according to the long-term processing uniformity.

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