CN108958162A - A kind of deep hole internal keyway shaping method based on symmetry error on-line checking and compensation - Google Patents

Abstract

A kind of deep hole internal keyway shaping method based on symmetry error on-line checking and compensation, by, translation object rotatable using space as research object, it is theoretical based on space projection, Orthogonal Composite and linear fit, establish the mathematical model of space symmetr degree error, it is the angle error and displacement error of fitting a straight line and reference line by space symmetr degree error separate, the compensation of symmetry error is measured and realized by way of quantitatively translating angle revolution, position.On this basis, design double-layer combined self-centering fixture and inline process type multiple degrees of freedom on-line measuring device, by exploitation symmetry error on-line checking numerical control program, with the measurement method for determining angle machining function and optimization, realization deep hole internal keyway symmetry error on-line checking and the efficient, high-precision of compensation, batch machining.

Description

A Deep Hole Keyway Slotting Machining Based on On-Line Symmetry Error Detection and Compensation method

technical field

The invention relates to a deep hole internal keyway slotting processing method based on on-line detection and compensation of symmetry errors.

Background technique

In recent years, with the continuous development of mechanical products in the direction of precision, complexity and miniaturization, the requirements for geometric tolerances of parts are getting higher and higher, making the measurement and evaluation of geometric errors more and more difficult. How to accurately obtain the geometric errors of parts It has gradually become a hot issue that engineers care about. As a core transmission part with high precision requirements, the efficient machining of keyways in deep holes has been widely concerned. In its processing process, geometric errors of parts caused by fixture positioning accuracy errors, detection device measurement errors, machine tool adjustment errors, etc. are inevitable, while advanced shape error evaluation theory and algorithm, precise measurement technology and devices and effective The error compensation machining method is an important means to reduce the geometric error.

At present, research mainly focuses on the measurement and evaluation of plane symmetry, but there is still a lack of specific research on the measurement and evaluation of space symmetry error.

The traditional deep hole keyway processing usually adopts broaching, planing, milling and slotting. These processing methods have their own processing characteristics, but in the processing process, they are often affected by conditions such as fixtures and testing methods. Large, it is easy to cause problems such as poor processing accuracy, failure to meet high symmetry requirements, and low processing efficiency.

The fixture design and processing methods involved in the current research content still cannot effectively meet the requirements of high precision, high efficiency and high degree of automation. question. At the same time, few researchers have carried out research on the symmetry control and precision machining methods and specific engineering examples of the circular quadrilateral keyway and the circular reference through groove.

Therefore, it is imperative and promising to develop the research on the online detection and compensation processing method of the symmetry error of the keyway in the deep hole.

Contents of the invention

The technical problem to be solved by the present invention is to provide a keyway slotting processing method in deep holes based on online detection and compensation of symmetry errors. By taking objects that can be rotated and translated in space as the research object, based on spatial projection, orthogonal combination and linear Fitting theory, establish a mathematical model of spatial symmetry error, separate the spatial symmetry error into the angle error and displacement error between the fitting line and the reference line, and realize the symmetry by means of angle rotation, position measurement and quantitative translation error compensation. On this basis, a double-layer combined self-centering fixture and an online multi-degree-of-freedom online detection device are designed, and the keyway in the deep hole is realized by developing the symmetry error online detection CNC program, using the fixed-angle processing function and the optimized measurement method. High-efficiency, high-precision, batch processing for online detection and compensation of symmetry errors.

In order to solve the above-mentioned problems, the technical solution of the present invention is: a deep hole inner keyway slotting processing method based on online detection and compensation of symmetry errors, which is characterized in that the method includes the following steps:

Aiming at the problems of low machining accuracy of the keyway in the quadrilateral deep hole, difficulty in controlling the symmetry between the machining keyway and the reference through groove, and poor machining symmetry, based on the analysis of the symmetry out-of-tolerance, the shape and position tolerance is used. The measurement principle, combined with the spatial symmetry error measurement and evaluation method, proposes a new processing method based on the angle between the projection line and the reference line to determine the symmetry error and based on the symmetry online detection and compensation;

Establish a spatial symmetry error detection and compensation mathematical model:

In order to realize the effective compensation of the symmetry error of the spatially rotatable and translational objects, it is separated into the angle error and the displacement error between the measured plane and the datum center plane. Among them, the angular error is based on the center plane of the reference rotation axis, and is measured by the angle between the center plane of the reference rotation axis and the measured plane. After measuring the coordinate values of each point on the reference actual contour and the measured actual contour, project them to the bottom surface and evaluate their respective symmetry angle errors according to the following methods.

Select the A and B planes on the space object M, and the C and D planes on N, divide them equally according to the length and width, and measure n uniformly distributed intersection points of the bisectors (A1～An, B1～Bn, D1～ Dn, C1～Cn) coordinates. The coordinate values of each evenly distributed intersection point can be expressed as Ai(X _Ai , Y _Ai , Z _Ai ), Bi(X _Bi ,Y _Bi ,Z _Bi ), Ci(X _Ci ,Y _Ci ,Z _Ci ) and Di(X _Di , Y _Di , Z _Di ), where i∈[1,n]. Using the spatial projection method, all uniformly distributed points are projected onto the bottom surface. After projection, the Z coordinate value of each point is zero, and other coordinate values remain unchanged. The coordinates corresponding to each plane point are A'i(X _Ai , Y _Ai ), B'i(X _Bi ,Y _Bi ), C'i (X _Ci , Y _Ci ) and D'i(X _Di , Y _Di ).

All projection points corresponding to planes A and B on the bottom surface of the orthogonal combination are connected two by two to form n ² straight lines, and the midpoints of all straight lines are calculated to obtain the midpoint set as:

Similarly, the midpoint set of n ² straight lines formed by all projected points of the C and D planes is:

According to the linear fitting theory, solve the linear fitting equation for each midpoint set. midpoint set The linear fitting equation for is:

y=Ax+B (3)

exist:

Similarly, set the midpoint set The linear fitting equation for is:

y=Cx+D (5)

exist:

Bring (1) and (2) into (4) and (6) respectively to obtain A, B, C and D respectively as follows:

Substituting the values of A and B in formula (7) into formula (3), and the values of C and D into formula (5), the angles between the two fitted straight lines and the reference straight line x=0 are respectively obtained as follows:

Based on the above calculation results, the spatial symmetry angle error E can be expressed as:

In the case of known datum plane (line), control the counterclockwise rotation angle of space object M to correct and compensate the parallelism of planes A and B relative to the datum plane (line); similarly, control space object N to rotate clockwise The angle can be corrected and compensated for the parallelism of C and D planes relative to the datum plane (line).

In order to further realize the symmetry error compensation of the objects M and N, it is necessary to realize the translation of the object N in the Y-axis direction on the basis of the above operations. Further complete the position measurement value, and then determine the amount that the object N needs to translate and complete the translation compensation.

A double-layer combined manual self-centering fixture is designed to realize radial self-centering positioning and axial end face positioning. At the same time, the reference base surface of the built-in reference channel is derived to ensure that its accuracy can be effectively detected and controlled;

The on-line multi-degree-of-freedom symmetry detection device is designed, and the basic method of using the device to realize the detection of symmetry error and the effective control of the device is proposed, and on this basis, a numerical control program for automatic detection of symmetry error is developed;

The batch processing of key grooves in deep holes with high symmetry is realized by adopting the angle compensation of the rotary shaft controlled by the CNC gear shaping machine and the translation compensation method of oblique tool clearance, combined with the method of CNC system program control for fixed-angle processing; combined with deep holes The example of internal keyway processing proves that the fixture structure and the online multi-degree-of-freedom symmetry detection device have good reliability, and the deep hole internal keyway slotting processing method based on symmetry detection and compensation can stably control the processing symmetry within 0.03 mm, which verifies the rationality and accuracy of this method, and provides a new way for the machining of keyways in deep holes with high symmetry.

Description of drawings

Below in conjunction with accompanying drawing, the present invention will be further described:

Fig. 1 is the mathematical model space measurement point projection schematic diagram that the present invention proposes,

Fig. 2 is a schematic diagram of the space symmetry error of the mathematical model proposed by the present invention,

Fig. 3 is the effect diagram after compensation of the angle error compensation of the mathematical model space symmetry degree proposed by the present invention,

Fig. 4 is the effect diagram after the quantitative translation compensation of the mathematical model space symmetry error proposed by the present invention,

Fig. 5 is a simplified diagram of the space symmetry error detection of the present invention,

Fig. 6 is a simplified diagram of the spatial symmetry error compensation of the present invention,

Fig. 7 is a transmission system diagram of the CNC gear shaping machine and the deep hole keyway slotting device controlled by symmetry detection and control of the present invention,

Fig. 8 is a flow chart of the online detection and compensation program design of the symmetry error of the present invention.

Detailed ways

The present invention is aimed at a processing method proposed by the patent number "CN 205593507 U" and the patent name "a deep hole keyway slotting device based on symmetry detection and control". The specific implementation process of the invention is further described. The following combined self-centering fixture and online multi-degree-of-freedom on-line detection device is a deep hole keyway slotting device based on symmetry detection and control.

As shown in Figures 1 to 8, by taking spatially rotatable and translational objects as the research object, based on spatial projection, orthogonal combination and linear fitting theory, a mathematical model of spatial symmetry error is established, and the spatial symmetry error is separated into pseudo The angle error and displacement error between the combined line and the reference line are realized, and the compensation of the symmetry error is realized through the angle rotation, position measurement and quantitative translation. On this basis, a double-layer combined self-centering fixture and an online multi-degree-of-freedom online detection device are designed, and the keyway in the deep hole is realized by developing the symmetry error online detection CNC program, using the fixed-angle processing function and the optimized measurement method. High-efficiency, high-precision, batch processing for online detection and compensation of symmetry errors.

Aiming at the problems of low machining accuracy of the keyway in the quadrilateral deep hole, difficulty in controlling the symmetry between the machining keyway and the reference through groove, and poor machining symmetry, based on the analysis of the symmetry out-of-tolerance, the shape and position tolerance is used. The measurement principle, combined with the spatial symmetry error measurement and evaluation method, proposes a new processing method based on the angle between the projection line and the reference line to determine the symmetry error and based on the symmetry online detection and compensation;

Establish a spatial symmetry error detection and compensation mathematical model:

In order to realize the effective compensation of the symmetry error of the spatially rotatable and translational objects, it is separated into the angle error and the displacement error between the measured plane and the datum center plane. Among them, the angular error is based on the center plane of the reference rotation axis, and is measured by the angle between the center plane of the reference rotation axis and the measured plane. After measuring the coordinate values of each point on the reference actual contour and the measured actual contour, project them to the bottom surface and evaluate their respective symmetry angle errors according to the following methods.

Select the A and B planes on the space object M, and the C and D planes on N, divide them equally according to the length and width, and measure n uniformly distributed intersection points of the bisectors (A1～An, B1～Bn, D1～ Dn, C1～Cn) coordinates. The coordinate values of each evenly distributed intersection point can be expressed as Ai(X _Ai , Y _Ai , Z _Ai ), Bi(X _Bi ,Y _Bi ,Z _Bi ), Ci(X _Ci ,Y _Ci ,Z _Ci ) and Di(X _Di , Y _Di , Z _Di ), where i∈[1,n]. Using the spatial projection method, all uniformly distributed points are projected onto the bottom surface. After projection, the Z coordinate value of each point is zero, and other coordinate values remain unchanged. The coordinates corresponding to each plane point are A'i(X _Ai , Y _Ai ), B'i(X _Bi ,Y _Bi ), C'i (X _Ci , Y _Ci ) and D'i (X _Di , Y _Di ).

All projection points corresponding to planes A and B on the bottom surface of the orthogonal combination are connected two by two to form n ² straight lines, and the midpoints of all straight lines are calculated to obtain the midpoint set as:

Similarly, the midpoint set of n ² straight lines formed by all projected points of C and D planes is:

According to the linear fitting theory, solve the linear fitting equation for each midpoint set. midpoint set The linear fitting equation for is:

y=Ax+B (3)

exist:

Similarly, set the midpoint set The linear fitting equation for is:

y=Cx+D (5)

exist:

Bring (1) and (2) into (4) and (6) respectively to obtain A, B, C and D respectively as follows:

Substituting the values of A and B in formula (7) into formula (3), and the values of C and D into formula (5), the angles between the two fitted straight lines and the reference straight line x=0 are respectively obtained as follows:

Based on the above calculation results, the spatial symmetry angle error E can be expressed as:

In the case of known datum plane (line), control the counterclockwise rotation angle of space object M to correct and compensate the parallelism of planes A and B relative to the datum plane (line); similarly, control space object N to rotate clockwise The angle can be corrected and compensated for the parallelism of C and D planes relative to the datum plane (line).

In order to further realize the symmetry error compensation of the objects M and N, it is necessary to realize the translation of the object N in the Y-axis direction on the basis of the above operations. Further complete the position measurement value, and then determine the amount that the object N needs to translate and complete the translation compensation.

The double-layer combined manual self-centering fixture is designed to realize radial self-centering positioning and axial end face positioning. At the same time, the reference base surface of the built-in reference channel is exported to ensure that its accuracy can be effectively detected and controlled;

Design an on-line multi-degree-of-freedom symmetry detection device, and propose a basic method to realize the detection of symmetry error and the effective control of the device by using the device, and develop a numerical control program for automatic detection of symmetry error on this basis;

Based on the CNC slotting machining principle and the space symmetry error measurement and compensation method proposed above, this paper conducts machining experiments on keyways in deep holes. In order to improve the processing efficiency and ensure the high efficiency of the online measurement and compensation process, this paper only completed the measurement task of two points on the single surface of the reference through groove and the keyway.

Use the online multi-degree-of-freedom symmetry detection device to complete the detection of points a, b, A and B, save and record the position coordinates of each point, and at this time meet:

In the formula, θ ₁ is the angle between the right side of the reference channel and the Y-axis axis; θ ₂ is the angle between the right side of the reference channel and the Y-axis axis; The coordinate value under the Y-axis coordinate of the degree detection device;

Since the C1 and C2 axes are both controlled by servo motors, after the coordinate data detection of the set detection point is completed through the online multi-degree-of-freedom symmetry detection device, the automatic compensation of the angle error can be realized through further data calculation and processing, so as to realize the straight line According to formula (10) and formula (11), the automatic detection and compensation of straightness and flatness can be solved to obtain the compensation to achieve straightness and flatness to meet the requirements of θ ₁ and θ ₂ respectively:

In the formula, R is the radius of gyration from point A to the rotation axis of C1;

After completing the online detection and compensation of the straightness and flatness of the spindle tool installation groove and the positioning reference plane for CNC slotting machining, the parallelism between the tool installation groove and the reference groove is realized.

In order to realize the online detection and control of symmetry, the following tasks need to be further completed:

(1) Use the online multi-degree-of-freedom symmetry detection device to complete the position coordinate detection of the spindle tool installation through groove and the positioning reference plane;

L＝|H _y -h _y | (14)

In the formula, H _y is the coordinate value of the right side of the reference channel under the Y-axis coordinate of the symmetry detection device; h _y is the coordinate value of the right side of the knife-loading channel under the Y-axis coordinate of the symmetry detection device; L is the coordinate value of the reference channel and the Y-axis coordinate of the symmetry detection device The coordinate difference of the right side of the tool through slot.

(2) Adjust the Y-direction coordinates by adjusting the oblique function of the CNC gear shaper, complete the adjustment of the tool processing position, and meet the requirements of the Y-axis compensation S:

In the formula, H is the standard width of the reference slot; h is the standard width of the tool slot (also the standard width of the keyway tool); S is the amount of symmetry translation compensation.

The batch processing of key grooves in deep holes with high symmetry is realized by adopting the angle compensation of the rotary shaft controlled by the CNC gear shaper machine and the translation compensation method of the oblique tool transfer, combined with the CNC system program to control the fixed angle processing;

Combined with the deep hole keyway processing example, it is verified that the fixture structure and the online multi-degree-of-freedom symmetry detection device have good reliability, and the deep hole keyway slotting processing method based on symmetry detection and compensation can stably control the processing symmetry The accuracy is within 0.03mm, which verifies the rationality and accuracy of this method, and provides a new way for the machining of key grooves in deep holes with high symmetry.

Claims (1)

1. A deep hole keyway slotting processing method based on online detection and compensation of symmetry errors, including a deep hole keyway slotting device for symmetry detection control, characterized in that the method includes the following method, the object is clamped to the symmetry After detecting and controlling the deep hole keyway slotting device, The first step is to establish a spatial symmetry error detection and compensation mathematical model, The second step, in order to realize the effective compensation of the symmetry error of the spatially rotatable and translational object, it is separated into the angle error and the displacement error between the measured plane and the reference center plane, Among them, the angular error is based on the center plane of the reference rotation axis, and is measured by the angle between the center plane of the reference rotation axis and the measured plane. After measuring the coordinate values of each point on the reference actual contour and the measured actual contour, project them to the bottom surface and evaluate the respective angle errors of symmetry according to the following methods; Select the A and B planes on the space object M, and the C and D planes on N, divide them equally according to the length and width, and measure n uniformly distributed intersection points of the bisectors (A1～An, B1～Bn, D1～ Dn, C1～Cn) coordinates. The coordinate values of each evenly distributed intersection point can be expressed as Ai(X _Ai , Y _Ai , Z _Ai ), Bi(X _Bi ,Y _Bi ,Z _Bi ), Ci(X _Ci ,Y _Ci ,Z _Ci ) and Di(X _Di , Y _Di , Z _Di ), where i∈[1,n]. Using the spatial projection method, all uniformly distributed points are projected onto the bottom surface. After projection, the Z coordinate value of each point is zero, and other coordinate values remain unchanged. The coordinates corresponding to each plane point are A'i(X _Ai , Y _Ai ), B'i(X _Bi ,Y _Bi ), C'i (X _Ci , Y _Ci ) and D′i(X _Di , Y _Di ), All projection points corresponding to planes A and B on the bottom surface of the orthogonal combination are connected two by two to form n ² straight lines, and the midpoints of all straight lines are calculated to obtain the midpoint set as: Similarly, the midpoint set of n ² straight lines formed by all projected points of the C and D planes is: According to the linear fitting theory, solve the linear fitting equation for each midpoint set. midpoint set The linear fitting equation for is: y=Ax+B (3) exist: Similarly, set the midpoint set The linear fitting equation for is: y=Cx+D (5) exist: Bring (1) and (2) into (4) and (6) respectively to obtain A, B, C and D respectively as follows: Substituting the values of A and B in formula (7) into formula (3), and the values of C and D into formula (5), the angles between the two fitted straight lines and the reference straight line x=0 are respectively obtained as follows: Based on the above calculation results, the spatial symmetry angle error E can be expressed as: In the case of known datum plane (line), control the counterclockwise rotation angle of space object M to correct and compensate the parallelism of planes A and B relative to the datum plane (line); similarly, control space object N to rotate clockwise angle, which can correct and compensate the parallelism of C and D planes relative to the datum plane (line), In order to further realize the symmetry error compensation of the objects M and N, it is necessary to realize the translation of the object N in the Y-axis direction on the basis of the above operations. Further complete the position measurement value, and then determine the amount that the object N needs to translate and complete the translation compensation, Finally, the batch processing of key grooves in deep holes with high symmetry is realized by adopting the angle compensation of the rotary axis controlled by the CNC gear shaping machine and the translation compensation method of the oblique tool letting, combined with the program control of the CNC system to control the fixed angle machining.