A method of modeling a cam profile curve

Abstract

The embodiment of the application discloses a cam profile curve modeling method. The cam profile curve modeling method comprises the following steps: drawing a base circle with a radius of r1; drawing a law curve, wherein the law curve of the X-axis and the Y-axis is set according to the following formula, and the law curve of the Z-axis is constant and 0; setting the center B of the base circle as the origin of the coordinate system; xt=R*cos(360*t), yt=R*sin(360*t); wherein t is a set increment variable, and the value range is 0 to 1; R is a line segment from the center B of the base circle, and 360*t is the angle through which the line segment R rotates counterclockwise around the center of the base circle; changing the length of the line segment R and obtaining N-stage profile curves after rotating the line segment R counterclockwise around the center of the base circle; and connecting the N-stage profile curves to obtain a cam profile curve; wherein N is a positive integer. The technical scheme of the application can avoid a large number of point data and draw an accurate and ideal cam profile curve.

Description

Technical Field

[0001] This invention relates to the field of cam design technology, and more particularly to a method for modeling cam profile curves. Background Technology

[0002] A cam is a component with a specific curved profile. It is widely used in general diesel engine components, and even in most other mechanical equipment, especially in various automated and semi-automated mechanical devices. Cams transmit motion to a follower that moves along its contoured surface. To understand the true motion state of the cam and its effect on the product, simulation and testing calculations are necessary. High-precision design details affect the test and calculation results; therefore, accurately establishing a cam model is essential. To meet various design requirements, cams are designed in different shapes.

[0003] Currently, the mainstream modeling method is to plot the coordinates of several points to fit the cam profile curve. Simpler cams are an exception and can be modeled using basic modeling methods. However, this method has two drawbacks: although it approximates the contour of a real cam as closely as possible, it is still a curve fitted from several points, and there will inevitably be some differences from the real contour; the more points, the more accurate the curve, but the larger the data volume and the larger the file size. Summary of the Invention

[0004] This invention provides a method for modeling cam profile curves to avoid large amounts of plotting data and to draw accurate and ideal cam profile curves.

[0005] According to one aspect of the present invention, a method for modeling a cam profile curve is provided, the method comprising:

[0006] Draw a base circle with radius r1;

[0007] Plot the rule curves, where the rule curves for the X and Y axes are set according to the following formulas, and the rule curve for the Z axis is selected to be constant and 0; the coordinate system is specified with the center B of the base circle as the origin;

[0008] xt=R*cos(360*t), yt=R*sin(360*t)

[0009] Where t is a set increment variable, with a value range of 0 to 1; R is a line segment starting from the center B of the base circle, and 360*t is the angle by which the line segment R rotates counterclockwise around the center of the base circle.

[0010] By changing the length of the line segment R and rotating it counterclockwise around the center of the base circle, N stages of contour curves are obtained. The N stages of contour curves are then connected to obtain the cam contour curve; where N is a positive integer.

[0011] Optionally, the value of N is 5; changing the length of the line segment R and rotating it counterclockwise around the center of the base circle to obtain a contour curve with 5 stages includes:

[0012] The contour curve of the base circle stage is obtained by changing the length of the line segment R and rotating it counterclockwise around the center of the base circle by a first preset angle; the contour curve of the lift stage is obtained by changing the length of the line segment R and rotating it counterclockwise around the center of the base circle by a second preset angle; the contour curve of the transition segment between the cam lift and return stage is obtained by changing the length of the line segment R and rotating it counterclockwise around the center of the base circle by a third preset angle; the contour curve of the cam return stage is obtained by changing the length of the line segment R and rotating it counterclockwise around the center of the base circle by a fourth preset angle; and the contour curve of the transition segment between the cam return and the base circle is obtained by changing the length of the line segment R and rotating it counterclockwise around the center of the base circle by a fifth preset angle.

[0013] Optionally, the process of forming the contour curve of the base circle stage includes: rotating the line segment R counterclockwise by 205° around the center B of the base circle, wherein the length of the line segment R in the base circle stage is equal to the radius r1 of the base circle.

[0014] Optionally, the process of forming the contour curve of the lift stage includes: changing the length of the line segment R and rotating it counterclockwise around the center B of the base circle to point A, drawing a perpendicular line through point A to intersect the extension of point B at point C, and constructing triangle ABC;

[0015] The length of line segment AB is c, the length of line segment BC is a, the length of line segment AC is b, and ∠Q = 360° - the angle rotated by the line segment R during the base circle stage and the rise stage + 25°, where a = b - r1;

[0016] According to the Law of Cosines, we can obtain... The length of segment R in the lift phase is equal to c.

[0017] Optionally, the process of forming the contour curve of the transition segment between the cam lift and return includes: changing the length of the line segment R and rotating it counterclockwise around the center B of the base circle to point D, with point F as the center of the transition segment between the cam lift and return, and connecting DF, DB and BF to construct triangle DBF;

[0018] The length of line segment BF is d, the length of line segment DF is e, the length of line segment DB is f, and ∠E is the angle between line segment BF and line segment DB.

[0019] According to the Law of Cosines, we can obtain... The length of segment R of the transition section between the cam lift and return is equal to f.

[0020] Optionally, the process of forming the profile curve of the cam return phase includes: changing the length of the line segment R and rotating it counterclockwise around the center B of the base circle to point G; drawing a perpendicular line through the center B of the base circle to intersect the extension of point G at point J; and connecting JB, JG and GB to construct a right triangle GBJ.

[0021] The length of line segment JB is g, the length of line segment GB is j, and ∠H is the angle between line segment JB and line segment GB.

[0022] According to the sine theorem, j = g / cosH, and the length of segment R in the cam return phase is equal to j.

[0023] Optionally, the process of forming the contour curve of the transition segment between the cam return and the base circle includes: changing the length of the line segment R and rotating it counterclockwise around the center B of the base circle to point K, with point M as the center of the transition segment between the cam return and the base circle, and connecting MB, MK and KB to construct triangle KBM.

[0024] The length of line segment MB is k, the length of line segment MK is l, the length of line segment KB is m, and ∠L is the angle between line segment MB and line segment KB.

[0025] According to the Law of Cosines, we can obtain... The length of R in the transition section between the cam return and the base circle is equal to m.

[0026] Optionally, it is determined whether the contour curve of the lift stage tends towards the center B of the base circle; if so, then... If not, then

[0027] Optionally, it is determined whether the profile curve of the transition segment between the cam lift and return stroke tends to the center B of the base circle; if so, then... If not, then

[0028] Optionally, it is determined whether the profile curve of the transition section between the cam return stroke and the base circle tends towards the center B of the base circle; if so, then... If not, then

[0029] The technical solution of this embodiment involves drawing a base circle with a radius of r1; drawing regular curves, wherein the regular curves of the X and Y axes are set according to formulas, and the regular curve of the Z axis is chosen to be constant and 0; specifying the center B of the base circle as the origin of the coordinate system; changing the length of the line segment R and rotating it counterclockwise around the center of the base circle to obtain N stages of contour curves; and connecting the N stages of contour curves to obtain the cam contour curve. The technical solution of this embodiment solves the problem in the prior art that there is a difference between the drawn cam contour curve and the real contour, and that the large amount of data during the drawing process leads to a large file size. The technical solution of this embodiment effectively reduces the huge amount of data in the modeling process and draws an accurate and ideal cam contour curve that is close to the real one.

[0030] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of the present invention, nor is it intended to limit the scope of the invention. Other features of the invention will become readily apparent from the following description. Attached Figure Description

[0031] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0032] Figure 1 This is a flowchart of a method for modeling a cam profile curve according to an embodiment of the present invention;

[0033] Figure 2 This is a schematic diagram of a modeling software interface for drawing rule curves according to an embodiment of the present invention;

[0034] Figure 3 This is a schematic diagram of a cam profile curve provided according to an embodiment of the present invention;

[0035] Figure 4 This is a schematic diagram of five stages of a cam profile curve according to an embodiment of the present invention;

[0036] Figure 5 This is a schematic diagram illustrating the formation process of a contour curve during the lift stage according to an embodiment of the present invention;

[0037] Figure 6 This is a schematic diagram illustrating the formation process of the profile curve of the transition section between the cam lift and return stroke according to an embodiment of the present invention.

[0038] Figure 7 This is a schematic diagram illustrating the formation process of the profile curve during the return stroke of a cam according to an embodiment of the present invention.

[0039] Figure 8 This is a schematic diagram illustrating the formation process of the profile curve of the transition section between the cam return and the base circle according to an embodiment of the present invention. Detailed Implementation

[0040] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0041] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0042] Figure 1 This is a flowchart of a method for modeling a cam profile curve according to an embodiment of the present invention, with reference to... Figure 1 This invention provides a method for modeling a cam profile curve, which includes the following steps:

[0043] S110. Draw a base circle with radius r1.

[0044] Specifically, the first step in modeling the cam profile curve is to draw the base circle. In UG NX software, draw a base circle with a radius of r1. The value of radius r1 is set as needed.

[0045] S120. Draw the rule curves, where the rule curves for the X and Y axes are set according to the following formulas, and the rule curve for the Z axis is selected to be constant and 0; the coordinate system is specified with the center B of the base circle as the origin;

[0046] xt=R*cos(360*t), yt=R*sin(360*t)

[0047] Where t is a set increment variable, with a value range of 0 to 1; R is a line segment starting from the center B of the base circle, and 360*t is the angle by which the line segment R rotates counterclockwise around the center of the base circle.

[0048] Specifically, among the various ways to create curves in NX, there is a rather special method—the rule curve. A rule curve is a spline curve where the X, Y, and Z coordinate values ​​change according to a set rule. Rule curves can be used to control the variation of certain parameters during the modeling process, such as controlling the change in the helix radius in a helix, controlling the curve shape, controlling the rounded cross-section of a surface, and controlling the angle or area during the construction of freeform surfaces.

[0049] Figure 2 This is a schematic diagram of a modeling software interface for drawing rule curves according to an embodiment of the present invention. (Refer to...) Figure 2 First, you need to create the expression before you can generate the rule curve. Open the software; in the tools drop-down menu, there is an expression option. Open this option as follows... Figure 2 As shown. You can set the required parameter expressions, so that the corresponding calculations can be performed automatically when drawing the graph. The expression sets the formula calculations for the X and Y axes; select the corresponding function name, which is the formula name given earlier. The Z-axis coordinate is always a constant 0. If the Z-axis coordinate is within a certain range, a height difference will appear at the end of the curve. Next, the curve is drawn using the relationship between X and Y. The angle through which line segment R rotates counterclockwise around the center of the base circle can be represented by 360*t. When the variable t changes from 0 to 1, it indicates that the angle has rotated 360°. At this point, the relationship between the length change of line segment R and the variable t has been defined. Next, define xt = R*cos(360*t), yt = R*sin(360*t), and by interpolating the rule curve, the ideal cam profile curve can be obtained.

[0050] S130. Change the length of line segment R and rotate it counterclockwise around the center of the base circle to obtain N stages of profile curves. Connect the N stages of profile curves to obtain the cam profile curve; where N is a positive integer.

[0051] Figure 3 This is a schematic diagram of a cam profile curve provided according to an embodiment of the present invention, for reference. Figure 3A line segment R originates from the center of the base circle. This cam can be understood as a line segment R rotating around the center of the base circle. Each time it rotates by a certain angle, the length of line segment R changes accordingly. The path traversed by the end of line segment R is the ideal cam profile curve. Therefore, for the cam, what always changes is the length of this line segment R. Thus, to obtain the cam profile curve, it is only necessary to define the relationship between the length of this line segment R and the variable t (t is a default variable in UG, ranging from 0 to 1). By continuously changing the length of line segment R and rotating it counterclockwise around the center of the base circle, N stages of profile curves are obtained. Finally, connecting these profile curves yields the ideal cam profile curve.

[0052] The technical solution of this embodiment involves drawing a base circle with a radius of r1; drawing regular curves, wherein the regular curves of the X and Y axes are set according to formulas, and the regular curve of the Z axis is chosen to be constant and 0; specifying the center B of the base circle as the origin of the coordinate system; changing the length of the line segment R and rotating it counterclockwise around the center of the base circle to obtain N stages of contour curves; and connecting the N stages of contour curves to obtain the cam contour curve. The technical solution of this embodiment solves the problem in the prior art that there is a difference between the drawn cam contour curve and the real contour, and that the large amount of data during the drawing process leads to a large file size. The technical solution of this embodiment effectively reduces the huge amount of data in the modeling process and draws an accurate and ideal cam contour curve that is close to the real one.

[0053] Figure 4 This is a schematic diagram of five stages of a cam profile curve according to an embodiment of the present invention, with reference to... Figure 4 Optionally, N is set to 5. The contour curves of five stages are obtained by changing the length of line segment R and rotating it counterclockwise around the center of the base circle: changing the length of line segment R and rotating it counterclockwise by a first preset angle to obtain the contour curve of the base circle stage; changing the length of line segment R and rotating it counterclockwise by a second preset angle to obtain the contour curve of the lift stage; changing the length of line segment R and rotating it counterclockwise by a third preset angle to obtain the contour curve of the transition segment between the cam lift and return; changing the length of line segment R and rotating it counterclockwise by a fourth preset angle to obtain the contour curve of the cam return stage; and changing the length of line segment R and rotating it counterclockwise by a fifth preset angle to obtain the contour curve of the transition segment between the cam return and the base circle.

[0054] Specifically, line segment R rotates around the center B of the base circle. Each time it sweeps through a certain preset angle, the length of line segment R changes accordingly. The path traversed by the end of line segment R is the ideal cam profile curve. In this embodiment, line segment R sequentially sweeps through the first preset angle, the second preset angle, the third preset angle, the fourth preset angle, and the fifth preset angle to obtain the profile curves for the base circle stage, the lift stage, the transition section between the cam lift and return, the cam return stage, and the transition section between the cam return and the base circle, respectively. The first, second, third, fourth, and fifth preset angles can be set according to actual needs, and this embodiment of the invention does not impose any limitations on this.

[0055] from Figure 4 As can be seen from the curves: the curve between point I and point II is the profile curve of the base circle stage; the curve between point II and point III is the profile curve of the lift stage; the curve between point III and point IV is the profile curve of the transition section between the cam lift and return; the curve between point IV and point V is the profile curve of the cam return stage; and the curve between point V and point I is the profile curve of the transition section between the cam return and the base circle.

[0056] Continue to refer to Figure 4 Optionally, the process of forming the profile curve of the base circle stage includes: rotating the line segment R counterclockwise by 205° around the center B of the base circle, and the length of the line segment R in the base circle stage is equal to the radius r1 of the base circle.

[0057] Specifically, the stage from point I to point II is the base circle stage. The value of line segment R in the base circle stage remains unchanged and is equal to the base circle radius r1. The angle swept by line segment R in the base circle stage is 180° + 25° = 205°.

[0058] Figure 5 This is a schematic diagram illustrating the formation process of a contour curve during the lift stage according to an embodiment of the present invention. (Refer to...) Figure 5 Optionally, the formation process of the contour curve in the ascending stage includes: changing the length of line segment R and rotating it counterclockwise around the center B of the base circle to point A; drawing a perpendicular line through point A to intersect the extension of point B at point C, thus constructing triangle ABC; the length of line segment AB is c, the length of line segment BC is a, the length of line segment AC is b, and ∠Q = 360° - the angle rotated by line segment R during the base circle stage and the ascending stage + 25°, where a = b - r1; according to the law of cosines, we can obtain... The length of segment R during the ascent phase is equal to c.

[0059] Specifically, after line segment R sweeps through a certain angle, the cam profile ends the base circle stage and enters the lift stage. For example... Figure 5As shown, triangle ABC can be constructed at this stage. Given a, b (a = b - r1) and ∠Q, find the length of c. Where ∠Q is the angle between line segments AB and BC, the angle swept by line segment R during the base circle stage is 180° + 25°, and 360° - the angle rotated by line segment R during the base circle stage and the ascent stage + 25° allows us to place the starting position at 0 degrees.

[0060] According to the Law of Cosines, b 2 =a 2 +c 2 -2accosB

[0061] The result of the transformation is: c 2 -2acosB*c+(a 2 -b 2 ) = 0

[0062] According to the quadratic formula, we can obtain...

[0063] After simplification, we get:

[0064] At this point, the length of segment R during the ascent phase is equal to c.

[0065] Optionally, determine whether the profile curve during the lift phase tends towards the center B of the base circle; if so, then... If not, then

[0066] Figure 6 This is a schematic diagram illustrating the formation process of the profile curve of the transition section between the cam lift and return stroke according to an embodiment of the present invention. (Refer to...) Figure 6 Optionally, the process of forming the profile curve of the transition segment between the cam lift and return stroke includes: changing the length of line segment R and rotating it counterclockwise around the center B of the base circle to point D, with point F as the center of the transition segment between the cam lift and return stroke; connecting DF, DB, and BF to construct triangle DBF; the length of line segment BF is d, the length of line segment DF is e, the length of line segment DB is f, and ∠E is the angle between line segment BF and line segment DB; according to the cosine theorem, we can obtain... The length of line segment R in the transition section between the cam lift and return is equal to f.

[0067] Specifically, after line segment R sweeps through a certain angle, the cam profile ends the lift phase and enters the transition phase between the lift and return stroke. For example... Figure 6 As shown, triangle DBF can be constructed at this stage. Given d, e, and ∠E, find the length of f.

[0068] According to the Law of Cosines, e 2 =d 2 +f 2-2dfcosE

[0069] According to the quadratic formula and its simplification, we can obtain:

[0070] At this point, the length of segment R of the transition section between the cam lift and return is equal to f.

[0071] Optionally, determine whether the profile curve of the transition section between the cam lift and return stroke tends to the center B of the base circle; if so, then... If not, then

[0072] Figure 7 This is a schematic diagram illustrating the formation process of the profile curve during the return stroke of a cam according to an embodiment of the present invention. (Refer to...) Figure 7 Optionally, the process of forming the profile curve during the cam return phase includes: changing the length of line segment R and rotating it counterclockwise around the center B of the base circle to point G; drawing a perpendicular line through the center B of the base circle that intersects the extension of point G at point J; connecting JB, JG, and GB to construct a right triangle GBJ; the length of line segment JB is g, the length of line segment GB is j, and ∠H is the angle between line segment JB and line segment GB; according to the sine theorem, j = g / cosH, and the length of line segment R during the cam return phase is equal to j.

[0073] Specifically, after line segment R sweeps through a certain angle, the cam profile ends the transition section between the lift and return strokes, entering the cam return phase. The profile curve of the cam return phase is a straight line segment, such as... Figure 7 As shown, a right triangle GBJ can be constructed. g can be obtained using trigonometric functions from the known quantities. Find the length of j. According to the sine theorem, j = g / cosH. At this point, the length of segment R during the cam's return phase is equal to j.

[0074] Figure 8 This is a schematic diagram illustrating the formation process of the profile curve of the transition section between the cam return and the base circle according to an embodiment of the present invention. (Refer to...) Figure 8 Optionally, the process of forming the profile curve of the transition segment between the cam return and the base circle includes: changing the length of line segment R and rotating it counterclockwise around the center B of the base circle to point K, with point M as the center of the transition segment between the cam return and the base circle; connecting MB, MK, and KB to construct triangle KBM; the length of line segment MB is k, the length of line segment MK is l, the length of line segment KB is m, and ∠L is the angle between line segments MB and KB; according to the law of cosines, we can obtain... The length R of the transition section between the cam return stroke and the base circle is equal to m.

[0075] Specifically, after line segment R sweeps through a certain angle, the cam profile ends the cam return phase and enters the transition section between the cam return and the base circle. For example... Figure 8 As shown, triangle KBM can also be constructed, where l, k, and ∠L are known. Find the length of m.

[0076] According to the Law of Cosines, l 2 =k 2 +m 2 -2kmcosL

[0077] According to the quadratic formula and its simplification, we can obtain:

[0078] At this point, the length R of the transition section between the cam return and the base circle is equal to m.

[0079] Optionally, determine whether the profile curve of the transition section between the cam return stroke and the base circle tends towards the center B of the base circle; if so, then... If not, then

[0080] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A method for modeling a cam profile curve, characterized in that, include: Draw a base circle with radius r1; Plot the rule curves, where the rule curves for the X and Y axes are set according to the following formulas, and the rule curve for the Z axis is selected to be constant and 0; the coordinate system is specified with the center B of the base circle as the origin; xt=R*cos(360*t), yt=R*sin(360*t) Where t is a set increment variable, with a value range of 0 to 1; R is a line segment starting from the center B of the base circle, and 360*t is the angle by which the line segment R rotates counterclockwise around the center of the base circle. By changing the length of the line segment R and rotating it counterclockwise around the center of the base circle, N stages of contour curves are obtained. The N stages of contour curves are then connected to obtain the cam contour curve; where N is a positive integer. The value of N is 5; by changing the length of the line segment R and rotating it counterclockwise around the center of the base circle, a contour curve with 5 stages is obtained, including: The contour curve of the base circle stage is obtained by changing the length of the line segment R and rotating it counterclockwise around the center of the base circle by a first preset angle; the contour curve of the lift stage is obtained by changing the length of the line segment R and rotating it counterclockwise around the center of the base circle by a second preset angle; the contour curve of the transition segment between the cam lift and return stage is obtained by changing the length of the line segment R and rotating it counterclockwise around the center of the base circle by a third preset angle; the contour curve of the cam return stage is obtained by changing the length of the line segment R and rotating it counterclockwise around the center of the base circle by a fourth preset angle; and the contour curve of the transition segment between the cam return and the base circle is obtained by changing the length of the line segment R and rotating it counterclockwise around the center of the base circle by a fifth preset angle.

2. The method according to claim 1, characterized in that, The process of forming the contour curve of the base circle stage includes: rotating the line segment R counterclockwise by 205° around the center B of the base circle, wherein the length of the line segment R in the base circle stage is equal to the radius r1 of the base circle.

3. The method according to claim 1, characterized in that, The process of forming the contour curve of the lift stage includes: changing the length of the line segment R and rotating it counterclockwise around the center B of the base circle to point A, drawing a perpendicular line through point A to intersect the extension of point B at point C, and constructing triangle ABC. The length of line segment AB is c, the length of line segment BC is a, the length of line segment AC is b, and ∠Q = The angle through which line segment R rotates during the base circle stage and the lift stage is +25°, where... ∠Q is the angle between line segment AB and line segment BC; According to the Law of Cosines, we can obtain... The length of segment R in the lift phase is equal to c.

4. The method according to claim 1, characterized in that, The process of forming the contour curve of the transition section between the cam lift and return includes: changing the length of the line segment R and rotating it counterclockwise around the center B of the base circle to point D, with point F as the center of the transition section between the cam lift and return, and connecting DF, DB and BF to construct triangle DBF. The length of line segment BF is d, the length of line segment DF is e, the length of line segment DB is f, and ∠E is the angle between line segment BF and line segment DB. According to the Law of Cosines, we can obtain... The length of the line segment R between the cam lift and return stroke is equal to f.

5. The method according to claim 1, characterized in that, The process of forming the profile curve of the cam return phase includes: changing the length of the line segment R and rotating it counterclockwise around the center B of the base circle to point G; drawing a perpendicular line through the center B of the base circle to intersect the extension of point G at point J; and connecting JB, JG and GB to construct a right triangle GBJ. The length of line segment JB is g, the length of line segment GB is j, and ∠H is the angle between line segment JB and line segment GB. According to the sine theorem, j = g / cosH, and the length of segment R in the cam return phase is equal to j.

6. The method according to claim 1, characterized in that, The process of forming the contour curve of the transition section between the cam return and the base circle includes: changing the length of the line segment R and rotating it counterclockwise around the center B of the base circle to point K, with the center of the transition section between the cam return and the base circle being point M, and connecting MB, MK and KB to construct triangle KBM. The length of line segment MB is The length of line segment MK is The length of line segment KB is ∠L is the angle between line segments MB and KB; According to the Law of Cosines, we can obtain... The length R of the transition section between the cam return and the base circle is equal to .

7. The method according to claim 3, characterized in that, Determine whether the contour curve of the lift stage tends towards the center B of the base circle; if so, then... If not, then .

8. The method according to claim 4, characterized in that, Determine whether the profile curve of the transition section between the cam lift and return stroke tends to the center B of the base circle. If so, then... If not, then .

9. The method according to claim 6, characterized in that, Determine whether the profile curve of the transition section between the cam return stroke and the base circle tends towards the center B of the base circle. If so, then... If not, then .

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