Method for detecting and evaluating the position of a cylinder bore of an engine cylinder block blank

Abstract

This invention discloses a method for detecting and evaluating the positional accuracy of cylinder bores in engine block blanks. The method includes steps such as cylinder block installation, cylinder axis data acquisition, bottom surface data acquisition, main bearing bore data acquisition, plane derivation, evaluation point establishment, angle evaluation, distance evaluation, coaxiality evaluation, and comprehensive evaluation. It identifies the core influencing factors that determine whether a qualified blank can be machined. The method breaks down the cylinder block positional accuracy, evaluates each sub-element separately, and determines whether the blank is qualified. It also determines whether a non-qualified blank has the potential to be machined into a qualified finished product through process adjustments, further guiding process adjustments. This method solves problems such as the inability to determine whether a non-qualified engine block blank can be machined into a qualified cylinder block product and the ineffective utilization of engine block blanks.

Description

Technical Field

[0001] This invention relates to the field of automotive parts, and more specifically to a method for detecting and evaluating the position of cylinder bores in engine block blanks. Background Technology

[0002] Engine block blanks are generally made of cast aluminum alloy. Ensuring the positional accuracy of the cylinder barrels through casting is extremely difficult, leaving machining allowances for subsequent machining to ensure the correct positional accuracy. Luxury, high-displacement cars often use V-type engine blocks. For V-type engine blocks, especially V12 engine blocks, both casting and machining costs are very high. Therefore, accurately measuring and evaluating engine block blanks, selecting qualified blanks for machining, and using reasonable measurement data to guide machining adjustments are crucial. Even if the engine block itself has dimensional defects from casting, it is essential to be able to produce a qualified finished cylinder block. This improves the yield rate, reduces the production cost of the blanks, and increases machining efficiency.

[0003] Currently, there are generally two methods for inspecting engine block blanks. One is scribing inspection, which is manual inspection. This method has low inspection efficiency, but the pass rate of the blank can be improved by allocating machining allowances to each machined surface. The other method is to use a coordinate measuring machine (CMM) to measure the position of the cylinder. This method requires pre-machining a bottom surface and two pins as measurement references. The machining accuracy of the measurement references has a significant impact on the measurement of the cylinder position. If the measurement references are not machined properly, it will directly lead to the scrapping of the engine block. When the evaluation result is unqualified, no guidance data can be provided for machining and debugging. Therefore, it is impossible to determine whether the unqualified blank can be machined into a qualified cylinder block product, and the blank cannot be effectively utilized to reduce production costs.

[0004] Existing methods for inspecting engine block blanks are inefficient and cannot determine whether unqualified blanks can be processed into qualified engine block blanks, resulting in the ineffective utilization of blanks. Summary of the Invention

[0005] This invention addresses the problems existing in the prior art by creatively devising a method for detecting and evaluating the position of cylinder bores in engine block blanks. By grasping the core influencing factors that determine whether a qualified blank can be manufactured, the cylinder bore position is disassembled, and each disassembled sub-element is evaluated separately to determine whether the blank is qualified.

[0006] The technical solution adopted to achieve the present invention is: a method for detecting and evaluating the cylinder bore position of an engine cylinder block blank, characterized in that it includes the following steps:

[0007] 1) Engine block blank installation:

[0008] Three identical pads are placed on the table of the coordinate measuring machine. The three identical pads evenly support the engine cylinder block blank, and the engine cylinder block blank is placed stably.

[0009] 2) Data acquisition of cylinder axis of engine block blank:

[0010] Using the coordinate measuring machine, sampling points are taken from the left and right rows of cylinders of the engine block blank. The cross section of the sampling points should cover the length of the cylinder. A set of uniform points reflecting the state of the cylinder is obtained. The sampling operation is repeated for the left and right rows of cylinders of the engine block blank. At the same time, the least squares method is used to calculate and collect the axes of 12 cylinders, namely the center lines L1 to L6 of the left row of cylinders and the center lines L7 to L12 of the right row of cylinders.

[0011] 3) Data acquisition of the bottom surface of the engine block blank:

[0012] Using the coordinate measuring machine, points are collected on the bottom surface of the engine cylinder block blank, covering the entire bottom surface of the engine cylinder block blank, to obtain a set of uniform points that reflect the state of the cylinder. The least squares method is used to calculate and generate the fitted bottom surface a4.

[0013] 4) Data acquisition of main bearing bores on engine block blanks:

[0014] Using the coordinate measuring machine, the main bearing holes of the engine block blank are sampled. Two cross-sectional sampling points are taken for each semicircle of the main bearing hole, for a total of 7 semicircles of the main bearing hole, and a total of 14 sets of sampling points are collected. A center line L14 is derived from the 14 sets of points.

[0015] 5) Exporting Plane Creation:

[0016] The center lines L1 to L6 of the left cylinder barrel are selected to fit a plane a1; the center lines L7 to L12 of the right cylinder barrel are selected to fit a plane a2; and the center plane a3 of planes a1 and a2 is fitted together.

[0017] 6) Establishment of evaluation points:

[0018] The intersection points P1 to P12 of the center lines L1 to L6 of the left cylinder barrel, L7 to L12 of the right cylinder barrel, and the center plane a3 were calculated using coordinate measuring machine software.

[0019] 7) Angle Evaluation:

[0020] The included angle b1 between the plane a1 and the plane a2 is calculated by using a three - coordinate software. Through the angle deviation, the maximum offset on one side during the cylinder barrel machining can be calculated. When compared with the machining allowance of the cylinder barrel, if the maximum offset on one side during the cylinder barrel machining is small, the cylinder block blank is qualified; the included angle b2 between the plane a3 and the plane a4 is calculated by using a three - coordinate software. Through the angle deviation, the maximum offset on one side during the bottom surface machining is calculated, and the maximum offset is the casting deviation of the cylinder barrel in the relative angular direction.

[0021] 8) Distance evaluation:

[0022] Select the center lines L1 - L6 of the left - column cylinder barrels and the center lines L7 - L12 of the right - column cylinder barrels in sequence, and obtain the intersection points P1 - P12 with the central plane a3 respectively. The distances H1 - H12 from the intersection points P1 - P12 to the plane a4 are used to calculate the maximum offset on one side during the bottom surface machining through the distance deviation of the distances H1 - H12. The maximum offset on one side during the bottom surface machining is the casting deviation of the engine cylinder block blank in the vertical bottom - surface height direction; select the center lines L1 - L6 of the left - column cylinder barrels and the center lines L7 - L12 of the right - column cylinder barrels. The three - coordinate software calculates the spacings h1 - h11 along the main bearing hole axis direction between L1 and L2, L2 and L3, L3 and L4, L4 and L5, L6 and L7, L7 and L8, L8 and L9, L9 and L10, L10 and L11, L11 and L12 respectively. The distance deviation of the h1 - h11 is used to calculate the maximum offset on one side during the cylinder barrel machining, and the maximum offset on one side during the cylinder barrel machining is the casting deviation of the cylinder barrel in the front - and - back direction.

[0023] 9) Coaxiality evaluation:

[0024] Select the center lines L1 - L6 of the left - column cylinder barrels and the center lines L7 - L12 of the right - column cylinder barrels to fit into an axis L13. The three - coordinate software calculates the coaxiality between the synthesized axis L13 and the main bearing hole axis L14, and calculates the maximum offset on one side during the main bearing hole machining through the coaxiality deviation of the coaxiality between the synthesized axis L13 and the main bearing hole axis L14.

[0025] 10) Summarize the data obtained from the angle evaluation in step 7), the distance evaluation in step 8), and the coaxiality evaluation in step 9), calculate the comprehensive deviation of the cylinder barrel position degree, and evaluate and judge the engine cylinder block blank according to the comprehensive deviation of the cylinder barrel position degree. If the engine cylinder block blank is qualified, based on the specific data of the angle evaluation in step 7), the distance evaluation in step 8), and the coaxiality evaluation in step 9), guide the setting of process parameters during the machining process; if the engine cylinder block blank is unqualified, based on the specific data of the angle evaluation in step 7), the distance evaluation in step 8), and the coaxiality evaluation in step 9), the potential to process qualified finished products can be adjusted through the machining process, and further improve the finished - product qualification rate.

[0026] Furthermore, the engine block is a V-type engine block or a V12 type engine block.

[0027] Furthermore, the pad is an adjustable pad.

[0028] Furthermore, the coordinate measuring machine is a single-sided movable bridge structure.

[0029] Furthermore, the engine cylinder block is made of cast aluminum alloy.

[0030] The beneficial effects of the present invention's method for detecting and evaluating the position of cylinder bores in engine block blanks are reflected in the following aspects:

[0031] A method for detecting and evaluating the cylinder bore position accuracy of engine block blanks addresses the problems of low efficiency, inability to determine whether substandard blanks can be machined into qualified cylinder block products, and ineffective utilization of blanks in existing engine block inspection methods. This method identifies the core influencing factors that determine whether a qualified blank can be machined, breaks down the cylinder bore position accuracy into its components, and evaluates each component separately to determine the blank's quality and whether substandard blanks have the potential to be machined into qualified products through process adjustments, thus further guiding process adjustments. Attached Figure Description

[0032] Figure 1 This is a flowchart of a method for detecting and evaluating the cylinder bore position of a V-type engine cylinder block blank;

[0033] Figure 2 This is a first schematic diagram of the measurement and clamping of the engine cylinder block blank in an embodiment;

[0034] Figure 3 This is a first schematic diagram of the measurement items for the engine block blank in the embodiment;

[0035] Figure 4 This is a second schematic diagram of the measurement items for the engine block blank in the embodiment;

[0036] Figure 5 In the embodiment, a second schematic diagram of the cylinder block blank measurement and clamping is shown.

[0037] Figure 6 This is a schematic diagram of the cylinder sampling points and axis fitting of the engine block blank in an embodiment;

[0038] Figure 7 This is a schematic diagram of the bottom sampling points and fitting plane of the engine cylinder block blank in the embodiment;

[0039] Figure 8In this embodiment, a schematic diagram of the sampling points and fitting axis of the main bearing hole of the engine cylinder block blank is shown.

[0040] In the figure: 1. Cylinder blank under test, 2. Pad, 3. Table of coordinate measuring machine, 4. Inner wall of cylinder, 5. Point sampling of inner wall of cylinder in coordinate measuring machine, 6. Calculated and derived cylinder axis, 7. Point sampling of bottom surface of cylinder in coordinate measuring machine, 8. Calculated and derived fitted bottom surface, 9. Main bearing hole of cylinder, 10. Point sampling of main bearing hole, L14. Fitted axis of main bearing hole. Detailed Implementation

[0041] The following is in conjunction with the appendix Figures 1-8 The present invention will be further described in detail with reference to specific embodiments. The specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0042] Example:

[0043] Measurement object: V12 engine cylinder block blank;

[0044] Measuring equipment: Coordinate measuring machine;

[0045] Measuring fixture: three identical pads.

[0046] As attached Figure 2 As shown, three identical pads are set on the table of the coordinate measuring machine. The three identical pads evenly support the engine cylinder block blank, and the engine cylinder block blank is placed stably.

[0047] Breakdown of measurement items:

[0048] As attached Figure 3 Appendix Figure 4 As shown, the positional accuracy of the cylinder block under test is broken down into the following measurement items:

[0049] 1. Angle (b1) between the plane (a1) formed by the center lines of the left cylinder (L1~L6) and the plane (a2) formed by the center lines of the right cylinder (L7~L12): This item evaluates whether the relative angle between the left and right cylinders is qualified.

[0050] 2. Angle (b2) between the center plane (a3) ​​of the plane formed by the center lines of the left cylinder barrels (a1) and the plane (a2) formed by the center lines of the right cylinder barrels and the bottom surface (a4) of the blank: This item evaluates whether the angle between the plane formed by the center lines of the left and right cylinder barrels and the bottom surface is acceptable. Theoretically, the two should be perpendicular. If this item is not acceptable, the two can be made perpendicular by adjusting the machining parameters of the bottom surface of the blank. Under normal circumstances, the machining allowance of the bottom surface of the blank is sufficient.

[0051] 3. The distance (H1~H12) between the intersection points (P1~P12) of each cylinder shaft axis (L1~L12) and the center plane and the bottom surface (a4): Theoretically, the distance is equal to the distance (H13) between the main bearing hole (D1) and the bottom surface. If this item is not qualified, the two can be made equal by adjusting the machining parameters of the blank main bearing hole. Under normal circumstances, the machining allowance of the blank main bearing hole is sufficient.

[0052] 4. The distance (h1~h11) between the intersection points (P1~P12) of each cylinder axis and the center plane along the axis of the main bearing hole: This evaluates the relative position between the cylinders. If this is not up to standard, it can be made equal by adjusting the machining parameters of the blank cylinder. Generally, the machining allowance of the blank cylinder is sufficient. 5. The coaxiality of the axis (L13) fitted by the intersection points (P1~P12) of each cylinder axis and the center plane with the main bearing hole axis (L14): This evaluates the relative position (theoretically coincident) of the axis (L13) and the main bearing hole. If this is not up to standard, it can be made up by adjusting the machining parameters of the blank main bearing hole. Generally, the machining allowance of the blank main bearing hole is sufficient.

[0053] As attached Figures 1-8 As shown, a method for detecting and evaluating the cylinder bore position of an engine block blank includes the following steps:

[0054] 1) Engine block blank installation:

[0055] Three identical pads are placed on the table of the coordinate measuring machine. The three identical pads evenly support the engine cylinder block blank, and the engine cylinder block blank is placed stably.

[0056] 2) Data acquisition of cylinder axis of engine block blank:

[0057] Using the coordinate measuring machine, sampling points are taken from the left and right rows of cylinders of the engine block blank. The cross section of the sampling points should cover the length of the cylinder. A set of uniform points reflecting the state of the cylinder is obtained. The sampling operation is repeated for the left and right rows of cylinders of the engine block blank. At the same time, the least squares method is used to calculate and collect the axes of 12 cylinders, namely the center lines L1 to L6 of the left row of cylinders and the center lines L7 to L12 of the right row of cylinders.

[0058] 3) Data acquisition of the bottom surface of the engine block blank:

[0059] Using the coordinate measuring machine, points are collected on the bottom surface of the engine block blank, covering the entire bottom surface of the blank. This yields a uniform set of points reflecting the cylinder's condition. The least squares method is then used to calculate and generate a fitted bottom surface a4, as shown in the attached figure. Figure 7 As shown;

[0060] 4) Data acquisition of the main bearing holes of the engine block blank:

[0061] Using the coordinate measuring machine, take points on the main bearing holes of the engine block blank. For each semi-circle of the main bearing holes, take points on 2 cross-sections. There are a total of 7 semi-circles of main bearing holes, and a total of 14 groups of points are taken. Derive a center line L14 from these 14 groups of points;

[0062] 5) Establishment of the derived plane:

[0063] Select the center lines L1 - L6 of the left column of cylinder barrels and fit them into a plane a1; select the center lines L7 - L12 of the right column of cylinder barrels and fit them into a plane a2; select the center plane a3 by fitting planes a1 and a2;

[0064] 6) Establishment of the evaluation points:

[0065] Use coordinate measuring software to calculate the intersection points P1 - P12 of the center lines L1 - L6 of the left column of cylinder barrels, the center lines L7 - L12 of the right column of cylinder barrels and the center plane a3;

[0066] 7) Angle evaluation:

[0067] Use coordinate measuring software to calculate the included angle b1 between plane a1 and plane a2. Through the angle deviation, the maximum unilateral offset during cylinder barrel machining can be calculated. Compare it with the machining allowance of the cylinder barrel. If the maximum unilateral offset during cylinder barrel machining is small, the engine block blank is qualified; use coordinate measuring software to calculate the included angle b2 between plane a3 and plane a4. Through the angle deviation, calculate the maximum unilateral offset during bottom surface machining. The maximum offset is the casting deviation of the cylinder barrel in the relative angular direction;

[0068] 8) Distance evaluation:

[0069] The center lines L1-L6 of the left cylinder block and L7-L12 of the right cylinder block are selected sequentially, and intersection points P1-P12 are obtained with the center plane a3 respectively. The distances H1-H12 from the intersection points P1-P12 to the plane a4 are calculated. The maximum offset on one side during bottom surface machining is calculated based on the deviation of the distances H1-H12. The maximum offset on one side during bottom surface machining is the casting deviation of the engine cylinder block blank in the vertical direction of the bottom surface height. The center lines L1-L6 of the left cylinder block and L7-L12 of the right cylinder block are selected sequentially. The cylinder centerlines L7 to L12 are used as references. The coordinate measuring machine software calculates the distances h1 to h11 between L1 and L2, L2 and L3, L3 and L4, L4 and L5, L6 and L7, L7 and L8, L8 and L9, L9 and L10, L10 and L11, and L11 and L12 along the axis of the main bearing hole. The distance deviations of h1 to h11 are used to calculate the maximum offset on one side during cylinder machining. The maximum offset on one side during cylinder machining is the casting deviation of the cylinder in the front-rear direction, as shown in the attached figure. Figure 3 As shown;

[0070] 9) Coaxiality evaluation:

[0071] The center lines L1-L6 of the left cylinder barrel and L7-L12 of the right cylinder barrel are selected to be fitted into an axis L13. The coaxiality of the composite axis L13 with the main bearing bore axis L14 is calculated using coordinate measuring machine software, as shown in the attached figure. Figure 4 As shown, the maximum offset on one side during the machining of the main bearing hole is calculated by the coaxiality deviation between the composite axis L13 and the main bearing hole axis L14, as shown in the attached figure. Figure 8 As shown;

[0072] 10) Summarize the data obtained from the angle evaluation in step 7), the distance evaluation in step 8), and the coaxiality evaluation in step 9), calculate the comprehensive deviation of the cylinder position, and evaluate the engine block blank based on the comprehensive deviation of the cylinder position. If the engine block blank is qualified, guide the setting of process parameters during processing based on the specific data of the angle evaluation in step 7), the distance evaluation in step 8), and the coaxiality evaluation in step 9. If the engine block blank is unqualified, the potential to produce qualified finished products can be improved by adjusting the processing technology based on the specific data of the angle evaluation in step 7), the distance evaluation in step 8), and the coaxiality evaluation in step 9, thereby further improving the finished product qualification rate.

[0073] The above description is merely a preferred embodiment of the present invention and is not restrictive. It should be noted that those skilled in the art can make various improvements and modifications, or even equivalents, without departing from the principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method of evaluating the position of a cylinder bore of an engine cylinder block blank, characterized by, It comprises the following steps: 1) engine cylinder block blank installation: Three identical pads are arranged on the table surface of a three-coordinate measuring machine, and the three identical pads uniformly support the engine cylinder block blank, and the engine cylinder block blank is placed stably; 2) cylinder axis data collection of the engine cylinder block blank: The three-coordinate measuring machine is used to collect points on the left column of cylinder barrels and the right column of cylinder barrels of the engine cylinder block blank, and the cross section of the collected points covers the length of the cylinder barrel, a group of uniform points reflecting the state of the cylinder barrel is obtained, and the point collection operation on the left column of cylinder barrels and the right column of cylinder barrels of the engine cylinder block blank is repeated, and the least square method is used for calculation, and the axes of 12 cylinder barrels, i.e. the center lines L1-L6 of the left column of cylinder barrels and the center lines L7-L12 of the right column of cylinder barrels, are collected; 3) bottom surface data collection of the engine cylinder block blank: The three-coordinate measuring machine is used to collect points on the bottom surface of the engine cylinder block blank, and the collected points cover the entire bottom surface of the engine cylinder block blank, a group of uniform points reflecting the state of the cylinder barrel is obtained, and the least square method is used for calculation, and a fitting bottom surface a4 is generated; 4) main bearing hole data collection of the engine cylinder block blank: The three-coordinate measuring machine is used to collect points on the main bearing hole of the engine cylinder block blank, and 2 cross section points are collected for each main bearing hole semicircle, a total of 7 main bearing hole semicircles, a total of 14 groups of points are collected, and a center line L14 is derived from the 14 groups of points; 5) derivation of a plane: The left column of cylinder barrel center lines L1-L6 is selected to fit into a plane a1, the right column of cylinder barrel center lines L7-L12 is selected to fit into a plane a2, and the center plane a3 of the two planes a1 and a2 is fitted; 6) evaluation point establishment: The intersection points P1-P12 of the left column of cylinder barrel center lines L1-L6, the right column of cylinder barrel center lines L7-L12 and the center plane a3 are calculated by the three-coordinate software; 7) angle evaluation: The angle b1 between the plane a1 and the plane a2 is calculated by the three-coordinate software, and the maximum offset of one side during cylinder processing is calculated through the angle deviation, compared with the processing allowance of the cylinder, if the maximum offset of one side during cylinder processing is small, the cylinder block blank is qualified, the angle b2 between the plane a3 and the plane a4 is calculated by the three-coordinate software, and the maximum offset of one side during bottom surface processing is calculated through the angle deviation, and the maximum offset is the casting deviation of the cylinder in the relative angle direction; 8) distance evaluation: The left column cylinder center lines L1-L6 and the right column cylinder center lines L7-L12 are selected in sequence, and the intersection points P1-P12 are obtained with the center plane a3, the distances H1-H12 of the intersection points P1-P12 to the plane a4 are calculated, the maximum offset of one side during bottom surface processing is calculated by the distance deviation of the distances H1-H12, and the maximum offset of one side during bottom surface processing is the casting deviation of the engine block blank in the vertical bottom surface height direction; the left column cylinder center lines L1-L6 and the right column cylinder center lines L7-L12 are selected, the distances h1-h11 of L1 and L2, L2 and L3, L3 and L4, L4 and L5, L6 and L7, L7 and L8, L8 and L9, L9 and L10, L10 and L11, and L11 and L12 along the main bearing hole axis direction are calculated by the three-coordinate software, and the maximum offset of one side during cylinder processing is calculated by the distance deviation of the distances h1-h11, and the maximum offset of one side during cylinder processing is the casting deviation of the cylinder in the front and back directions; 9) coaxiality evaluation: The left column cylinder center lines L1-L6 and the right column cylinder center lines L7-L12 are fitted into the axis L13, the coaxiality of the combined axis L13 and the main bearing hole axis L14 is calculated by the three-coordinate software, and the maximum offset of one side during main bearing hole processing is calculated by the coaxiality deviation of the coaxiality of the combined axis L13 and the main bearing hole axis L14; 10) the data obtained by the angle evaluation of step 7), the distance evaluation of step 8), and the coaxiality evaluation of step 9) are summarized, the comprehensive deviation of the cylinder position degree is calculated, the engine block blank is evaluated according to the comprehensive deviation of the cylinder position degree, if the engine block blank is qualified, the specific data of the angle evaluation of step 7), the distance evaluation of step 8), and the coaxiality evaluation of step 9) are used to guide the setting of process parameters in the processing process; if the engine block blank is unqualified, the specific data of the angle evaluation of step 7), the distance evaluation of step 8), and the coaxiality evaluation of step 9) can be used to adjust the processing process to process qualified products with potential, and further improve the qualified product rate.

2. A method of evaluating the position of a cylinder bore of an engine cylinder block blank according to claim 1, characterized by The engine block is a V-type engine block or a V12-type engine block.

3. A method of evaluating the position of a cylinder bore of an engine cylinder block blank according to claim 1, characterized by, The pad is an adjustable pad.

4. The method of claim 1, wherein the method is characterized by: The three-coordinate measuring machine is a single-side movable bridge structure.

5. The method of claim 1, wherein the method is characterized by: The material of the engine block is cast aluminum alloy. The material of the engine block is cast aluminum alloy.

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