CN-115795707-B - Machining process dimension chain calculation method based on dynamic tolerance diagram

Abstract

The invention discloses a machining process dimension chain calculation method based on a dynamic tolerance diagram, and relates to the technical field of machine part manufacturing and cutting machining processes. The method is characterized by comprising the steps of firstly calculating an independent qualified area of a target ring according to an initial condition and an extremum method, secondly calculating the maximum upper deviation and the minimum lower deviation of the target ring, thirdly calculating the dynamic upper deviation and the dynamic lower deviation of the target ring, fourthly calculating the dynamic qualified area of the target ring, and fifthly drawing a dynamic tolerance zone diagram of a process size chain. The invention aims to determine the complete qualified range in the calculation of the obtained size chain, avoid misjudgment and waste, and save the production cost. The invention has the beneficial effects of 1, completely expressing all the qualified ranges of the parts, 2, avoiding misjudgment and waste in production, avoiding economic loss, 3, expanding the qualified range, reducing the processing difficulty and further reducing the production cost.

Inventors

• ZHANG YUE
• HAN LI
• YANG HERAN
• LI QIANG
• SUN XINGWEI

Assignees

• 沈阳工业大学

Dates

Publication Date

20260505

Application Date

20221101

Claims (2)

1. 1. The machining process dimension chain calculation method based on the dynamic tolerance diagram is characterized by comprising the following steps of: Step one, calculating an independent qualified area of a target ring according to initial conditions and an extremum method; Calculating the maximum upper deviation and the minimum lower deviation of the target ring; calculating the dynamic upper deviation and the dynamic lower deviation of the target ring; Step four, calculating a dynamic qualified area of the target ring; Drawing a dynamic tolerance diagram of a process size chain; step one, calculating an independent qualified zone of the target ring according to initial conditions and an extremum method, wherein the specific process is as follows: the calculation is carried out according to formulas (1), (2) and (3): (1) (2) (3) Wherein A 0 、A z 、A j is the nominal size of the closed loop, the added loop and the subtracted loop respectively, ES 0 、ES z 、ES j is the upper deviation of the closed loop, the added loop and the subtracted loop respectively, EI 0 、EI z 、EI j is the lower deviation of the closed loop, the added loop and the subtracted loop respectively, m is the number of the added loops, n is the number of the subtracted loops; When the target ring is a minus ring, the number is j1, and the calculation result is that the nominal size is A j1 , the upper deviation is ES j1 , the lower deviation is EI j1 , namely, the qualification range of the actual size Aa j1 of the target ring j1 is A j1 + EI j1 ≤Aa j1 ≤A j1 + ES j1 , the deviation is EI j1 ≤Ea j1 ≤ES j1 , wherein Ea j1 is the actual deviation of the target ring j 1; When the target ring is the added ring, the number is z1, and the calculation result is that the nominal size is A z1 , the upper deviation is ES z1 , and the lower deviation is EI z1 , namely the qualification range of the actual size Aa z1 of the target ring z1 is A z1 +EI z1 ≤Aa z1 ≤A z1 + ES z1 , the deviation is EI z1 ≤Ea z1 ≤ES z1 , wherein Ea z1 is the actual deviation of the target ring z 1; the qualification range of the target ring j1 or the target ring z1 is independent of the sizes of other component rings and the closed ring, and is an independent qualification zone; Step two, calculating the maximum upper deviation and the minimum lower deviation of the target ring, wherein the specific process is as follows: when the target ring is a minus ring, the maximum upper deviation and the minimum lower deviation of the target ring are calculated by the following steps: maximum deviation: (4) Minimum deviation: (5) wherein ES ' j1 is the maximum upper deviation of the target ring j1 and EI' j1 is the minimum lower deviation of the target ring j 1; When the target ring is an added ring, the maximum upper deviation and the minimum lower deviation are calculated by the following steps: Maximum deviation: (6) Minimum deviation: (7) Wherein ES ' z1 is the maximum upper deviation of the target ring z1 and EI' z1 is the minimum lower deviation of the target ring z 1; Step three, calculating the dynamic upper deviation and the dynamic lower deviation of the target ring, wherein the specific process is as follows: when the target ring is a minus ring, the method for calculating the dynamic upper deviation and the dynamic lower deviation comprises the following steps: Dynamic upper bias: (8) Dynamic lower bias: (9) wherein ES Σj1 is the dynamic upper deviation of the target ring j1, EI Σj1 is the dynamic lower deviation of the target ring j 1; when the target ring is the added ring, the calculation method of the dynamic upper deviation and the dynamic lower deviation is as follows: Dynamic upper bias: (10) Dynamic lower bias: (11) Wherein ES Σz1 is the dynamic upper bias of the target ring z1, EI Σz1 is the dynamic lower bias of the target ring z 1; the dynamic qualified area of the target ring is calculated, and the specific process is as follows: Relationship between the actual deviation Ea of the closed ring and the component ring dimensions And EI is less than or equal to Ea is less than or equal to ES relation of each size, and the relation is calculated as follows: when the target ring is the minus ring, the dynamic qualified area of the target ring j1 is: (13) wherein Ex is a dynamic deviation variable, E aj1 is the actual deviation of the target ring j 1; When the target ring is the added ring, the dynamic qualified area of the target ring z1 is: (14) Where E az1 is the actual deviation of the target ring z 1.
2. 2. The method for calculating the processing technology dimension chain based on the dynamic tolerance map of claim 1, wherein the drawing technology dimension chain dynamic tolerance map in the fifth step comprises the following specific steps: The dynamic tolerance diagram of the process size chain adopts a rectangular coordinate system, the abscissa represents the design size or the size deviation of the ring increase, and the ordinate represents the size deviation of the ring decrease; Setting the sum of all ring-increasing maximum values as sigma ES z , the sum of all ring-increasing minimum values as sigma EI z , the sum of all ring-decreasing maximum values as sigma ES j and the sum of all ring-decreasing minimum values as sigma EI j , wherein the four values can be enclosed into a rectangle which is an independent qualified area; On a dimension chain dynamic tolerance diagram, each coordinate point corresponds to the dimension of the increasing ring and the decreasing ring, so that the dimension of a closed ring of the point can be calculated, and the points with equal dimensions of the closed ring are connected into a line, and the line is defined as a closed ring equal-dimension line; When the target ring is the minus ring, the ring size is known, so the values of Sigma ES z and Sigma EI z are fixed, and ES j1 and EI j1 of the target ring j1 are calculated according to the extremum method; ES j1 is calculated from the upper left corner of the rectangle of the independent qualified zone, and the closed loop is in lower deviation EI 0 , and the equal-size line of the closed loop is formed in the direction of 45 DEG from the upper left corner to the upper right corner of the rectangle of the independent qualified zone, so that the equal-size line intersects with the straight line of Sigma ES z to form a triangle, namely the upper conditional qualified zone; EI j1 is calculated at the right lower corner of the rectangle of the independent qualified area, at the moment, the closed loop is in upper deviation ES 0 , and the equal-size line of the closed loop is formed in the direction of 45 degrees from the right lower corner of the rectangle of the independent qualified area to the left lower side, so that the equal-size line intersects with the straight line of Sigma EI z to form a triangle, namely the lower condition qualified area; When the target ring is an increasing ring, the decreasing ring size is known, so the values of Sigma ES j and Sigma EI j are fixed, and ES z1 and EI z1 of the target ring z1 are calculated according to the extremum method; ES z1 is calculated at the right lower corner of the rectangle of the independent qualified zone, at this time, the closed loop is in the upper deviation ES 0 , and the equal-size line of the closed loop is made in the direction of 45 DEG from the right lower corner of the rectangle of the independent qualified zone to the right upper side, so that the equal-size line intersects with the straight line of Sigma ES j to form a triangle, namely the right conditional qualified zone; EI z1 is calculated at the upper left corner of the rectangle of the independent qualified area, at this time, the closed loop is in lower deviation EI 0 , and the equal-size line of the closed loop is made in the direction of 45 degrees from the upper left corner of the rectangle of the independent qualified area to the left and the lower, so that the equal-size line intersects with the straight line of Sigma EI j to form a triangle, namely the left conditional qualified area.

Description

Machining process dimension chain calculation method based on dynamic tolerance diagram Technical Field The invention relates to the technical field of machine part manufacturing and cutting processing technology, in particular to a processing technology dimension chain calculating method based on a dynamic tolerance diagram. Background In the process of manufacturing and cutting machining process of mechanical parts, part sizes of part structures can be connected end to form a machining process size chain, most of sizes in the machining process size chain are directly obtained by machining according to the size precision marked by drawings, but one size is a naturally formed size after machining of other sizes is finished, and the machining process can be called a closed ring. In the process size chain, the size directly obtained by the process is called a component ring. The component rings are divided into an increasing ring and a decreasing ring, wherein when other component rings are unchanged, a certain component ring is increased, a closed ring is increased, and the component ring is called an increasing ring, whereas when other component rings are unchanged, a certain component ring is increased, a closed ring is decreased, and the component ring is called a decreasing ring. In actual production, particularly in mass production, if the design requirement obtains the dimensional accuracy of the closed ring, and when the dimensional has the problems of difficult measurement, incapability of direct processing, non-overlapping reference and the like, the dimensional accuracy of the formed ring is obtained through calculation of a processing technology dimensional chain, and the dimensional accuracy of the closed ring is indirectly ensured through processing the formed ring. For calculation of a processing technology size chain, the traditional method mainly comprises an extremum method, a probability method and the like, but the calculation result can generate a so-called false reject zone, the qualified range of the size of the component ring cannot be completely described, and the situation that the size of a part is in the false reject zone and is misjudged to be wasted is likely to occur, so that economic loss is caused. Disclosure of Invention The invention aims to provide a processing technology dimension chain calculation method based on a dynamic tolerance diagram, which aims to determine the complete qualified range in the calculation of the obtained dimension chain, avoid misjudgment and waste, and save the production cost. The technical scheme is as follows: The machining process dimension chain calculation method based on the dynamic tolerance diagram is characterized by comprising the following steps of: Step one, calculating an independent qualified area of a target ring according to initial conditions and an extremum method; Calculating the maximum upper deviation and the minimum lower deviation of the target ring; calculating the dynamic upper deviation and the dynamic lower deviation of the target ring; Step four, calculating a dynamic qualified area of the target ring; And fifthly, drawing a dynamic tolerance zone diagram of the process size chain. Preferably, in the first step, the independent qualified area of the target ring is calculated according to an extremum method according to the initial condition, and the specific process is as follows: The calculation is performed according to the formulas (1), (2) and (3): Wherein A0, az and Aj are nominal sizes of a closed loop, an increased loop and a decreased loop respectively, ES0, ESz and ESj are upper deviations of the closed loop, the increased loop and the decreased loop respectively, EI0, EIz and EIj are lower deviations of the closed loop, the increased loop and the decreased loop respectively, m is the number of the increased loop, n is the number of the decreased loop; When the target ring is a minus ring, the number is j1, the calculation result is that the nominal size is Aj1, the upper deviation is ES j1, the lower deviation is EI j1, namely, the qualification range of the actual size Aaj of the target ring j1 is aj1+ EIj less than or equal to Aaj1 less than or equal to aj1+ ESj1, the deviation is EIj1 less than or equal to Eaj1 less than or equal to ESj1, wherein Eaj1 is the actual deviation of the target ring j 1; When the target ring is the added ring, the number is z1, the calculation result is that the nominal size is Az1, the upper deviation is ESz1, and the lower deviation is EIz1, namely, the qualification range of the actual size Aaz1 of the target ring z1 is Az1+ EIz1 which is not more than Az1 which is not more than Az1+ ESz1, the deviation is EIz1 which is not more than Eaz1 which is not more than ESz1, wherein Eaz1 is the actual deviation of the target ring z1; the pass range of the target ring j1 or the target ring z1 is independent pass zone irrespective of the sizes of other component rings and the closed ri