A self-reference milling method for cylinder head combustion chamber surface

Abstract

The present application relates to the field of vehicle technology, and in particular to a method for self-reference milling of a cylinder head combustion chamber surface, comprising the following steps: pre-positioning a workpiece on a machine tool, and setting the top surface of the workpiece toward the machine tool; selecting measurement points and combustion chamber surface positioning pins on the combustion chamber surface of the workpiece; measuring the coordinate values ​​of each measurement point, and correcting the angle of the workpiece and the machine tool relative to the spindle for the first time based on the coordinate values; measuring the coordinate values ​​of each combustion chamber surface measurement point after the first correction, and establishing a machining reference surface in the Z direction based on the average height value; measuring the coordinate values ​​of each combustion chamber surface positioning pin again, and correcting the angle of the workpiece and the machine tool relative to the spindle for the second time based on the coordinate values ​​and theoretical coordinate values; and milling the combustion chamber surface. The present application embodiment provides a method for self-reference milling of a cylinder head combustion chamber surface to solve the problem in the related art that the dimensional accuracy is not easy to be guaranteed due to the conversion of the reference when machining the cylinder head combustion surface.

Description

Technical Field

[0001] The present application relates to the field of vehicle technology, and in particular to a self-reference milling method for a cylinder head combustion chamber surface. Background Art

[0002] The combustion chamber surface of the cylinder head bears important functions such as bearing, sealing, and assembly reference of the engine. It has a significant impact on the engine performance and a decisive influence on the engine durability. If the processing is unqualified, the engine quality will inevitably be reduced, and even directly lead to engine failure.

[0003] In the related technology, the traditional processing method of the cylinder head combustion chamber surface is to use the top surface positioning, clamping the intake and exhaust side surfaces, and milling the combustion chamber surface with a disc milling cutter, or online measuring the combustion chamber surface before milling and feeding back to the machine tool, and milling a fixed processing allowance according to the measured value.

[0004] However, the above processing method involves a reference conversion and is easily affected by the parallelism and height of the top and bottom surfaces of the previous process, resulting in key dimensions such as the distance between the processed camshaft hole and the valve seat cone surface and the combustion chamber surface being difficult to stably guarantee, thereby causing a decrease in engine performance. Summary of the invention

[0005] The embodiment of the present application provides a method for self-reference milling of a cylinder head combustion chamber surface, so as to solve the problem in the related art that when machining the cylinder head combustion surface, the dimensional accuracy is difficult to be guaranteed due to the conversion of the reference.

[0006] In order to achieve the above objectives, the present application provides a self-referenced milling method for a cylinder head combustion chamber surface, which comprises the following steps:

[0007] Pre-positioning the workpiece on the machine tool, and arranging the top surface of the workpiece toward the machine tool;

[0008] At least three measuring points and at least two combustion chamber surface locating pins are selected on the combustion chamber surface of the workpiece; at least three combustion chamber surface measuring points are selected because three points can determine a plane, and the three combustion chamber surface measuring points are distributed in a triangular shape on the combustion chamber surface, and the coordinate values ​​of the points are effectively measured. The average value of the three can also more accurately reflect the average height of the combustion chamber surface, and a reference plane is established with the combustion chamber surface as a reference.

[0009] Measuring the coordinate values ​​of each of the measuring points, and correcting the angles of the workpiece and the machine tool relative to the spindle for the first time according to the measured coordinate values;

[0010] The coordinate values ​​of the measurement points on the combustion chamber surface after the first correction are measured again to obtain the average height, and the machining reference surface in the Z direction is established based on the average height;

[0011] Measuring the coordinate values ​​of the positioning pins on the combustion chamber surface, and based on the coordinate values ​​and the theoretical coordinate values, correcting the angles of the workpiece and the machine tool relative to the spindle for a second time;

[0012] Milling of the combustion chamber face.

[0013] In some embodiments, establishing the Z coordinate axis includes the following steps:

[0014] The height of each measuring point is measured and the average value is taken. The average value is taken as the zero point, and the Z-direction reference plane is established in a direction parallel to the combustion chamber surface.

[0015] In some embodiments, the second correction of the angle between the workpiece and the machine tool relative to the spindle comprises the following steps:

[0016] The coordinate value between any two combustion chamber surface locating pins is measured and compared with the theoretical coordinate value. If the data are consistent, no adjustment is made. If the data are inconsistent, the angle between the workpiece and the machine tool relative to the spindle is corrected for a second time.

[0017] In some embodiments, the method further comprises the following steps:

[0018] After the combustion chamber surface is milled, the coordinate values ​​of each measuring point on the combustion chamber surface are measured with the reference plane after the second correction as the reference to determine whether they are consistent in the Z direction.

[0019] In some embodiments, pre-positioning the workpiece on the machine tool and arranging the top surface of the workpiece toward the machine tool further comprises the following steps:

[0020] The workpiece is positioned on the machine tool using a fixture.

[0021] In some embodiments, the following steps are further included before milling the combustion chamber surface:

[0022] Specify a location and measure the Z value of the specified location before milling;

[0023] Using a milling cutter to mill a specified margin in the Z direction on the combustion chamber surface at the specified position;

[0024] The Z value of the designated position after milling is measured using a detection device to determine the actual milling allowance and to make a difference with the value of the designated allowance.

[0025] In some embodiments, using a milling cutter to mill a specified margin on the combustion chamber surface at the specified position in the Z direction includes the following steps:

[0026] The displacement of the milling cutter in the Z direction is made zero.

[0027] In some embodiments, there are three combustion chamber surface measurement points, and any one of the combustion chamber surface measurement points is outside the straight line where the other two combustion chamber surface measurement points are located.

[0028] In some embodiments, a top surface positioning block and a top surface positioning hole are provided on the top surface.

[0029] In some embodiments, there are two combustion chamber surface positioning holes.

[0030] The beneficial effects of the technical solution provided by this application include:

[0031] The embodiment of the present application provides a method for self-reference milling of a cylinder head combustion chamber surface. Since the top surface of the workpiece is pre-positioned on the machine tool first, the positioning reference at this time is the top surface of the workpiece; and since combustion chamber surface measurement points and combustion chamber surface positioning pins are provided on the combustion chamber surface of the workpiece, the detection device can perform a first measurement of the spatial coordinate values ​​of the combustion chamber surface measurement points, and at least three combustion chamber surface measurement points can determine a surface. After the coordinate values ​​are measured, the machine tool adjusts the position of the workpiece relative to the spindle so that it faces the spindle, which is convenient for operation;

[0032] Then use the detection device to measure the corrected combustion chamber surface measurement points for the second time, and establish the Z-direction reference plane for the combustion chamber surface of the workpiece according to the average height value of each positioning block, and use the average height value of the measurement point as the Z-direction reference plane to determine the reference plane for subsequent workpiece processing, and convert the reference plane from the top surface to the combustion chamber surface;

[0033] The detection device is then used to measure the coordinate value of the locating hole on the combustion chamber surface, and compared with the theoretical hole position, the angle of the workpiece and the combustion chamber surface relative to the main axis is corrected again, and the pre-positioning pin is converted from the top surface to the combustion chamber surface locating hole. At this point, the conversion from the original top surface as the reference surface to the combustion chamber surface to be milled as the reference surface and the conversion of the locating hole to the combustion chamber surface as the locating surface is completed, which is consistent with the subsequent processing datum, product design datum, and assembly datum, achieving a higher combustion chamber surface milling accuracy. Therefore, it can solve the problem in the related technology that when processing the cylinder head combustion surface, the dimensional accuracy is not easy to be guaranteed due to the conversion of the datum. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0035] Figure 1 A schematic diagram of a workpiece and a fixture provided in an embodiment of the present application;

[0036] Figure 2 A schematic diagram of a detection device and a workpiece provided in an embodiment of the present application;

[0037] Figure 3 This is a schematic diagram of the test of the milling cutter provided in an embodiment of the present application before formal milling.

[0038] In the figure: 1. workpiece; 2. machine tool; 21. fixture; 3. combustion chamber surface; 31. combustion chamber surface measuring point; 32. combustion chamber surface locating pin; 4. top surface; 41. top surface locating block; 42. top surface locating hole; 5. spindle; 6. detection device; 7. milling cutter; 8. measurement position before milling; 9. machining starting position; 10. milling end position. DETAILED DESCRIPTION

[0039] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0040] The embodiment of the present application provides a method for self-reference milling of a cylinder head combustion chamber surface, which can solve the problem in the related art that when machining the cylinder head combustion surface, the dimensional accuracy is difficult to ensure due to the conversion of the reference.

[0041] The method steps are as follows:

[0042] S1 . Pre-position the workpiece 1 on the machine tool 2 , and place the top surface 4 of the workpiece 1 toward the machine tool 2 .

[0043] Combination Figure 1 As shown, the top surface 4 has a top surface positioning block 41 and a top surface positioning hole 42, which are used to pre-position the workpiece 1 on the machine tool 2. After the workpiece 1 is installed on the machine tool 2, the combustion chamber surface 3 of the workpiece 1 is arranged toward the side away from the machine tool 2;

[0044] At this time, the machine tool 2 itself has a machine tool coordinate system, and the machine tool 2 can drive the workpiece 1 fixed thereon to move. Since the top surface 4 is in contact with the machine tool 2, the top surface 4 is still used as the positioning reference surface.

[0045] Specifically, when the machine tool 2 is in a planar state, the top surface 4 of the workpiece 1 is placed downward, the combustion chamber surface 3 is facing upward, and the workpiece 1 is carried to the machine tool 2 by the truss. The machine tool 2 is provided with a fixture 21. The top surface positioning block 41 and the top surface positioning hole 42 on the top surface 4 constitute the top surface pre-positioning reference. The fixture 21 is clamped on the side of the workpiece 1 to fix the workpiece 1 on the machine tool 2.

[0046] Optionally, the top surface positioning block 41 has three, combined Figure 1 As shown, three points can determine a plane, and three top surface positioning blocks 41 are distributed on the top surface 4 in a triangular shape.

[0047] It should be noted that Figure 1 The side shown in the figure is the combustion chamber surface 3, and the top surface 4 is located on the side opposite to the combustion chamber surface 3. The top surface positioning block 41 and the top surface positioning hole 42 marked in the figure cannot be seen on the combustion chamber surface 3, but only indicate the position relative to the combustion chamber surface 3 for reference.

[0048] S2. Select at least three combustion chamber surface measurement points 31 and at least two combustion chamber surface positioning pins 32 on the combustion chamber surface 3 of the workpiece 1.

[0049] Specifically, at least three combustion chamber surface measurement points 31 are selected because three points can determine a plane, see Figure 1 As shown, three combustion chamber surface measurement points 31 are selected in this embodiment. The three combustion chamber surface measurement points 31 are distributed in a triangular shape on the combustion chamber surface 3, and the coordinate values ​​of the points are effectively measured. The average value of the three can also more accurately reflect the average height of the combustion chamber surface 3, and a reference plane is established with the combustion chamber surface 3 as a reference.

[0050] The two combustion chamber surface positioning pins 32 play a positioning role, and transfer the positioning reference of the top surface positioning hole 42 of the original top surface 4 to the combustion chamber surface positioning pins 32, completing the conversion of the reference surface from the top surface 4 to the combustion chamber surface 3.

[0051] S3. Measure the coordinate values ​​of the three combustion chamber surface measurement points 31, and correct the angles of the workpiece 1 and the machine tool 2 relative to the spindle 5 according to the measured coordinate values.

[0052] Specifically, the spindle 5 is provided with a detection device 6 and a milling cutter 7, and the detection device 6 is used to measure the coordinate value of the specified position;

[0053] According to the machining procedure, the workpiece 1 on the machine tool 2 should be turned over to the position to be machined, that is, the combustion chamber surface 3 faces the spindle 5, see Figure 1 and Figure 2 , Figure 1 The state of the workpiece 1 when it is clamped on the machine tool 2, and the workpiece 1 should be placed vertically, and then combined with Figure 2 As shown, Figure 2 The workpiece 1 is turned over to make the combustion chamber surface 3 face and be perpendicular to the spindle 5. At this time, the detection device 6 installed on the machine tool 2 detects the coordinate values ​​of the three combustion chamber surface measurement points 31, and corrects the spatial angle of the machine tool 2 after data analysis. This is the first online measurement and correction.

[0054] Specifically, the coordinate system of the machine tool 2 itself is used as a reference to measure the coordinate values ​​of the three combustion chamber surface measurement points 31, compare them with the theoretical coordinate values, and determine whether the installation position of the workpiece 1 is correct.

[0055] For example, when the machine tool 2 itself is in a vertical state, if the workpiece 1 is placed on the machine tool 2 in a close relationship, the Z-axis coordinate values ​​of the three combustion chamber surface measurement points 31 measured should be consistent. If they are inconsistent, it means that the workpiece 1 is not placed on the machine tool 2 in a close relationship, or a problem occurs in the previous processing of the workpiece 1. At this time, the machine tool 2 issues an alarm, and the operator checks the workpiece 1.

[0056] Furthermore, the relative position of the workpiece 1 and the machine tool 2 is allowed to have a certain error value. Specifically, the present application provides an embodiment, namely:

[0057] The machine tool 2 includes a fixture 21, an A-axis and a B-axis, and the workpiece 1 is mounted on the fixture 21, and the fixture 21 is mounted on the A-axis or the B-axis, wherein the A-axis and the B-axis can rotate around the coordinate axis of the machine tool coordinate system, such as the A-axis rotates around the X-axis of the machine tool 2, and the B-axis rotates around the Y-axis of the machine tool 2, and a certain rotation adjustment value is provided for the A-axis and the B-axis, and the rotation adjustment value can be 0.2°; after measuring the combustion chamber surface measurement point 31, if the A-axis and B-axis rotation values ​​that need to be adjusted are less than or equal to the rotation adjustment value, the Z-axis coordinate values ​​of the three combustion chamber surface measurement points 31 can be made consistent, then the machine tool 2 automatically completes the adjustment according to the program, so that the Z values ​​of the three combustion chamber surface measurement points 31 in the machine tool 2 coordinate system are consistent; if the A-axis and B-axis rotation values ​​that need to be adjusted are greater than 0.2°, then the machine tool 2 issues an alarm, and the operator checks the workpiece 1, such as whether the workpiece 1 is clamped in place, or whether there is an abnormality in the previous process.

[0058] That is, if the workpiece 1 is not positioned properly and an offset occurs, the coordinate value of the measuring point 3 on the combustion chamber surface 3 can be detected by the detection device 6, compared with the theoretical coordinate value, and analyzed and judged. If the offset is not large, it can be remedied by correction. For example, the A-axis and B-axis rotation values ​​of the above embodiment are less than or equal to the rotation adjustment value. If the offset is large and exceeds the correction limit, the machine tool 2 alarms to prompt the operator to check whether the workpiece 2 is placed properly.

[0059] S4. Measure the coordinate values ​​of the three combustion chamber surface measurement points 31 again, take the three measured heights as an average value, and establish the machining reference surface in the Z direction.

[0060] Specifically, the coordinate values ​​of the three combustion chamber surface measurement points 31 corrected in step S3 are measured this time, and the combustion chamber surface measurement points 31 are all points on the combustion chamber surface 3. The heights of the three are averaged to establish the Z-direction machining reference plane, that is, the height of the combustion chamber surface 3 is taken as the Z direction machining reference plane. 0, with the combustion chamber surface 3 as the Z-direction reference plane. At this time, the Z-direction reference plane is transferred from the top surface 4 to the combustion chamber surface 3, which is consistent with the product design reference.

[0061] S5. Measure the coordinate values ​​of any two combustion chamber surface positioning pins 32, and based on the coordinate values ​​and the theoretical coordinate values, correct the angles of the workpiece 1 and the machine tool 2 relative to the spindle 5.

[0062] The purpose of this step is to transfer the top surface positioning hole 42 , which was originally used as the processing reference hole and located on the top surface 4 , to the combustion chamber surface positioning pin 32 located on the combustion chamber surface 3 .

[0063] Specifically, the center distance value between any two combustion chamber surface locating pins 32 is certain. If the center distance value measured by the detection device 6 is different from the theoretical value, it means that the combustion chamber surface 3 is not completely facing the main shaft 5, and adjustment is required. This is also a necessary step to transfer the locating pin hole from the top surface 4 to the combustion chamber surface 3;

[0064] Furthermore, if the measured value is consistent with the theoretical value, no adjustment is made and step S6 is directly entered. If the values ​​are inconsistent, the angles of the workpiece 1 and the machine tool 2 relative to the spindle 5 are adjusted so that the combustion chamber surface 3 faces the spindle 5.

[0065] Preferably, the combustion chamber surface positioning pin 32 is as follows Figure 1 As shown, there are two, and the straight line where the two combustion chamber surface locating pins 32 are located is parallel to the length direction of the workpiece 1. In this step, the Y-direction processing reference plane is determined by measuring the coordinate values ​​of the two combustion chamber surface locating pins 32, that is, the surface parallel to the length direction of the workpiece 1 and perpendicular to the Z-direction reference plane is used as the Y-direction reference plane; preferably, the straight line where the two combustion chamber surface locating pins 32 are located is used as the Y-axis, and the direction parallel to the width direction of the workpiece 1 is used as the X-axis.

[0066] The specific steps for comparing the measured coordinate values ​​with the theoretical coordinate values ​​are as follows: first determine the center distance between the two combustion chamber surface locating pins 32, which is the theoretical center distance. This step can be completed in the previous work, and then use the detection device 6 to detect the adjusted coordinate value of the combustion chamber surface locating pin 32 (the coordinate value at this time is the coordinate value adjusted in step S4, that is, X and Y are still measured and obtained based on the coordinate system of the machine tool 2, and the Z coordinate value is measured and obtained based on the coordinate system adjusted in step S4), and calculate the center distance between the two. If there is an error between the measured center distance and the theoretical center distance, it means that the combustion chamber surface 3 is clamped and offset, and the machine tool 2 needs to be readjusted to make the measured center distance value consistent with the theoretical center distance;

[0067] Furthermore, the coordinate values ​​of the two combustion chamber surface positioning pins 32 are measured, and the A axis and the B axis of the machine tool 2 are adjusted based on the coordinate values ​​and the theoretical coordinate values, and the corrected combustion chamber surface positioning pins 32 are used as new positioning references.

[0068] It should be noted that after the Z-direction machining reference plane has been determined, the Z values ​​of the two combustion chamber surface locating pins 32 are consistent, and only the value between the two combustion chamber surface locating pins 32 needs to be considered.

[0069] After the above steps S1 to S5, the positioning reference is transferred from the top surface positioning reference during pre-positioning to a new positioning reference with the combustion chamber surface 3 as the positioning surface and the two combustion chamber surface positioning pins 32 as positioning holes, which is consistent with the subsequent processing reference, product design reference, and assembly reference.

[0070] S6. Milling the combustion chamber surface 3.

[0071] Specifically, the milling cutter program is called to mill the combustion chamber surface 3 using the one surface (combustion chamber surface 3) and two pins (combustion chamber surface positioning pins 32) after the above-mentioned reference conversion as the new reference;

[0072] The embodiment of the present application provides a method for self-reference milling of a cylinder head combustion chamber surface. Since the top surface 4 of the workpiece 1 is pre-positioned on the machine tool 2, the positioning reference at this time is the top surface 4 of the workpiece 1; and since the combustion chamber surface 3 of the workpiece 1 is provided with a combustion chamber surface measurement point 31 and a combustion chamber surface positioning pin 32, the detection device 6 can perform a first measurement of the spatial coordinate value of the combustion chamber surface measurement point 31, and at least three combustion chamber surface measurement points 31 can determine a surface. After measuring the coordinate value, the machine tool 2 adjusts the position of the workpiece relative to the spindle 5 so that it faces the spindle 5, which is convenient for operation;

[0073] The detection device 6 is then used to perform a second measurement on the corrected combustion chamber surface measurement point 31. According to the average height of each combustion chamber surface measurement point 31, a Z-direction reference plane is established for the combustion chamber surface 3 of the workpiece 1. The average height value of the combustion chamber surface measurement point 31 is used as the Z-direction reference plane to determine the reference plane for subsequent workpiece processing, and the reference plane is converted from the top surface 4 to the combustion chamber surface 3.

[0074] The detection device 6 is then used to measure the coordinate value of the combustion chamber surface locating pin 31, and compared with the theoretical pin hole position, the angle of the workpiece 1 and the combustion chamber surface 3 relative to the main axis 5 is corrected again, and the pre-positioning pin is converted from the top surface 4 to the combustion chamber surface measurement point 31 on the combustion chamber surface 3. At this point, the conversion from the original top surface 4 as the reference surface to the combustion chamber surface 3 to be milled as the reference surface and the locating hole is completed, and the conversion to the combustion chamber surface 3 as the locating surface is completed, which is consistent with the subsequent processing datum, product design datum, and assembly datum, achieving a higher combustion chamber surface milling accuracy. Therefore, it can solve the problem in the related technology that when processing the cylinder head combustion surface, the dimensional accuracy is not easy to be guaranteed due to the conversion of the datum.

[0075] In some optional embodiments, step S6 further includes step S7:

[0076] After milling, the detection device 6 is used again to detect the coordinate values ​​of the three combustion chamber surface measurement points 31 on the milled combustion chamber surface 3, and the coordinate values ​​are fed back to the machine tool after data processing. The purpose is to detect whether the flatness of the combustion chamber surface 3 after milling is out of tolerance to prevent defective parts from flowing out.

[0077] In some optional embodiments, see Figure 1 As shown, a fixture 21 is provided on the machine tool 2, and the fixture 21 is used to limit the workpiece 1 on the machine tool 2. Specifically, there are three fixtures 21. Since the workpiece is placed vertically during milling, two of the fixtures 21 are arranged at the lower edge of the workpiece 1 and are dispersed to play a lifting role, and the other is arranged at the upper edge of the workpiece 1 to clamp the workpiece 1 from top to bottom;

[0078] Furthermore, combined with Figure 1 As shown, the positions of the three clamps 21 are close to the top surface positioning block 41, which is in the opposite direction to the positioning direction of the top surface positioning block 41, and plays a role in strengthening the tightening and clamping of the workpiece 1 in the form of reaction force.

[0079] In some optional embodiments, in step S1 , three top surface positioning blocks 41 are selected and used. The three top surface positioning blocks 41 are theoretically of equal height so that the workpiece 1 is parallel to the surface of the machine tool 2 .

[0080] Furthermore, three top surface positioning blocks 41 determine a Z-direction reference plane, but when the workpiece 1 is placed on the machine tool 2, there will still be a horizontal displacement, that is, it is necessary to determine the X-direction and Y-direction reference planes. Therefore, a top surface positioning hole 32 is selected on the combustion chamber surface 3, and a positioning pin is provided at the corresponding position of the fixture 21 (or the machine tool 2). The positioning hole 32 is inserted on the positioning pin to form a limit for the workpiece 1 to limit the freedom of the workpiece 1 on the machine tool 2.

[0081] In some optional embodiments, the machine tool 2 is provided with a detection device 6, and before step S6, the following steps are further included:

[0082] After correcting the angle of the machine tool 2, a coordinate system is established with the combustion chamber surface 3 and the two combustion chamber surface positioning pins 31 on the combustion chamber surface. The detection device 6 measures the coordinate value of the pre-milling measurement position 8 by moving a certain coordinate value (x, y) relative to the two combustion chamber surface positioning pins 31 as the Y-direction reference at the above coordinates, and feeds back to the machine tool 2;

[0083] Call the milling cutter 7, the milling cutter first reaches the processing starting position 9, and then moves in the negative direction (i.e. Figure 3 The milling cutter moves a certain coordinate value (in the direction indicated by the Y-axis arrow) to the milling end position 10, at which time the Z direction will mill a fixed allowance value Z1.

[0084] The detection device 6 is called, and the detection device 6 detects the pre-milling measurement position 8 in the above coordinate system, and feeds back the measured coordinate value to the machine tool 2. The machine tool 2 analyzes and processes the coordinate values ​​measured before and after milling and makes conditional judgments. If the coordinate value consistency condition is met, the next step will be executed. Otherwise, the machine tool 2 will alarm and prompt to check the tool.

[0085] The above is the process of online automatic calibration of the tool, which can effectively check the adjustment accuracy of the milling cutter 7 and monitor the abnormal processing, ensuring the reliability of the processing accuracy. It has high positioning accuracy, stable and reliable operation, and low cost. It is suitable for semi-finishing and finishing of box parts, especially for finishing with one-side two-pin positioning.

[0086] The present invention provides a method for milling the combustion chamber surface of a cylinder head with the combustion chamber surface 3 as the reference. The combustion chamber surface 3 is milled with the tool calibrated automatically online, and the three-dimensional space coordinate system of the machine tool 2 is corrected in real time, so as to accurately compensate for the error of the fixture 21 during the rotation of the turntable, and achieve a high milling accuracy of the combustion chamber surface 3; through multiple online measurement analysis feedback before and after processing, the three-dimensional space turntable fixture is corrected in real time, the turntable fixture error is accurately compensated, and the reference conversion is accurately realized. The processing process is monitored in real time and online feedback is provided, and defective products of the previous process are discovered in time, and defective parts are not accepted, which effectively ensures the processing accuracy of the hole system on the combustion chamber surface and other surfaces, and can prevent the outflow of defective parts.

[0087] In the description of the present application, it should be noted that the terms "upper", "lower", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. Unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be a connection between the two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to the specific circumstances.

[0088] It should be noted that, in this application, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.

[0089] The above description is only a specific implementation of the present application, so that those skilled in the art can understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest range consistent with the principles and novel features applied for herein.

Claims

1. A method for self-reference milling of a cylinder head combustion chamber surface, characterized in that: It includes the following steps: Pre-positioning a workpiece (1) on a machine tool (2), and arranging the top surface (4) of the workpiece (1) toward the machine tool (2); Selecting at least three measuring points (31) and at least two combustion chamber surface positioning pins (32) on the combustion chamber surface (3) of the workpiece (1); Measuring the coordinate values ​​of each of the measuring points (31), and correcting the angles of the workpiece (1) and the machine tool (2) relative to the spindle (5) for the first time based on the measured coordinate values; The coordinate values ​​of each combustion chamber surface measurement point (31) after the first correction are measured again to obtain an average height value, and a machining reference surface in the Z direction is established based on the average height value; Measuring the coordinate values ​​of each of the combustion chamber surface positioning pins (32), and based on the coordinate values ​​and theoretical coordinate values, correcting the angles of the workpiece (1) and the machine tool (2) relative to the spindle (5) for a second time; Milling the combustion chamber surface (3); There are three combustion chamber surface measurement points (31), and any one of the combustion chamber surface measurement points (31) is outside the straight line where the other two combustion chamber surface measurement points (31) are located; The method of establishing a Z-direction machining reference surface based on the height average value comprises: establishing a Z-direction reference surface for the combustion chamber surface (3) of the workpiece (1) according to the height average values ​​of the combustion chamber surface measurement points (31), and using the average height value of the combustion chamber surface measurement points (31) as the Z-direction reference surface.

2. The cylinder head combustion chamber surface self-reference milling method according to claim 1, characterized in that: The second correction of the angle between the workpiece (1) and the machine tool (2) relative to the spindle (5) comprises the following steps: The coordinate value between any two combustion chamber surface positioning pins (32) is measured and compared with the theoretical coordinate value. If the data are consistent, no adjustment is made. If the data are inconsistent, the angle between the workpiece (1) and the machine tool (2) relative to the spindle (5) is corrected for a second time.

3. The cylinder head combustion chamber surface self-reference milling method according to claim 1, characterized in that: The method further comprises the following steps: After the combustion chamber surface (3) is milled, the coordinate values ​​of each combustion chamber surface measurement point (31) are measured with the reference plane after the second correction as a reference to determine whether they are consistent in the Z direction.

4. The cylinder head combustion chamber surface self-reference milling method according to claim 1, characterized in that: Pre-positioning the workpiece (1) on the machine tool (2) and arranging the top surface of the workpiece (1) toward the machine tool (2) further comprises the following steps: The workpiece (1) is positioned on the machine tool (2) using a clamp (21).

5. The cylinder head combustion chamber surface self-reference milling method according to claim 1, characterized in that: Before the combustion chamber surface (3) is milled, the following steps are also included: Specify a location and measure the Z value of the specified location before milling; Using a milling cutter (7) to mill a specified margin in the Z direction on the combustion chamber surface (3) at the specified position; A detection device (6) is used to measure the Z value of the designated position after milling, to determine the actual milling allowance, and to make a difference with the value of the designated allowance.

6. The cylinder head combustion chamber surface self-reference milling method according to claim 5, characterized in that: Using a milling cutter (7) to mill a specified margin on the combustion chamber surface (3) at the specified position in the Z direction comprises the following steps: The displacement of the milling cutter (7) in the Z direction is made zero.

7. The cylinder head combustion chamber surface self-reference milling method according to claim 1, characterized in that: A top surface positioning block (41) and a top surface positioning hole (42) are provided on the top surface (4).

8. The cylinder head combustion chamber surface self-reference milling method according to claim 1, characterized in that: There are two combustion chamber surface positioning pins (32).

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