CN111723476A - Shear torque modeling method for scrap shears with oblique shear blades - Google Patents
Shear torque modeling method for scrap shears with oblique shear blades Download PDFInfo
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Abstract
The invention discloses a modeling method for shearing torque of a bevel shear blade scrap shear, which comprises the following steps: according to the forming process of the theoretical cutting edge arc, the theoretical cutting edge arc is replaced by three standard arcs with the same end points; step 2) after a standard circular arc with three end points same as the theoretical cutting edge circular arc is obtained, establishing a conversion model according to the fact that the height difference between the circular arc highest point and the circular arc end point of the theoretical cutting edge circular arc is the same as the height difference between the circular arc highest point and the circular arc end point of the standard circular arc, and obtaining the circular arc radius of the substitute theoretical cutting edge circular arc; step 3) obtaining a shearing force through a disc shear shearing force model according to the arc radius of the substitute theory shear blade arc in the step 2); step 4), obtaining a cutter head shearing angle according to the cutter head shearing angle model; step 5) obtaining the theoretical shearing torque of the cutter head through a cutter head shearing torque model according to the shearing force of the step 3) and the cutter head shearing angle of the step 4); and 6) designing a cutter head of the oblique shearing edge scrap shears according to the obtained theoretical shearing torque.
Description
Technical Field
The invention belongs to the technical field of shearing torque of a bevel shear blade scrap shear, and particularly relates to a modeling method of shearing torque of a bevel shear blade scrap shear.
Background
In metallurgical enterprises, there is an apparatus for breaking waste edges after trimming a circular disc, which is called a trimming shear, and the trimming shear can be classified into a straight-edge shear, an oblique-edge shear, and a screw shear according to the types of shearing edges. The inclined-blade shears are preferentially adopted in steel mills due to the characteristics that the shearing force of the inclined-blade shears is small, and the straight-blade shears are convenient to process and install. The torque prediction of the power shears becomes the key point of the design of the power shears. In the design of the domestic aspect, the prediction is carried out according to analogy by referring to foreign data or finite element analysis and the like; the analogy prediction lacks theoretical basis and has low accuracy; the finite element prediction is time-consuming, high in cost and low in flexibility, data used by other methods are difficult to measure, or the measurement is difficult to be accurate, so that the obtained shearing torque is low in precision.
Disclosure of Invention
The invention aims to overcome the defects of the prior art, provides a modeling method for shearing torque of a bevel shear blade scrap shear, and overcomes the defects of the prior art that 1: the analogy prediction lacks theoretical basis and has low accuracy; 2: the finite element prediction is time-consuming, high in cost and low in flexibility, and the precision of the obtained shearing torque is low due to the fact that data used by other methods are difficult to measure or the measurement is difficult to be accurate; 3: in the prior art, a shear torque modeling method does not exist, and the problems of low accuracy, low precision of obtained shear torque and the like are fundamentally solved according to different modeling directions.
In order to solve the technical problem, the technical scheme of the invention is as follows: a shear torque modeling method for a scrap shear with a bevel shear blade comprises the following steps:
step 1) replacing a theoretical cutting edge arc by three standard arcs with the same end points according to the forming process of the theoretical cutting edge arc;
step 2) after a standard circular arc with three end points same as the theoretical cutting edge circular arc is obtained, establishing a conversion model according to the indexing circle radius of the cutter head where the cutting edge is located, the cutting edge inclination angle, the cutter head width where the cutting edge is located, the cutting edge length and the circular arc radius of the substitute theoretical cutting edge circular arc according to the fact that the height difference between the circular arc highest point and the circular arc end point of the theoretical cutting edge circular arc is the same as the height difference between the circular arc highest point and the circular arc end point of the standard circular arc, and obtaining the circular arc radius of the substitute theoretical cutting edge circular arc;
step 3) obtaining a shearing force through a disc shear shearing force model according to the arc radius of the substitute theory shear blade arc in the step 2);
step 4), obtaining a cutter head shearing angle according to the cutter head shearing angle model;
step 5) obtaining the theoretical shearing torque of the cutter head through a cutter head shearing torque model according to the shearing force of the step 3) and the cutter head shearing angle of the step 4);
and 6) designing a cutter head of the inclined shear blade scrap cutter according to the theoretical shearing torque obtained in the step 5), wherein the sheared torque of the cutter head of the inclined shear blade scrap cutter is larger than the theoretical shearing torque.
Preferably, the forming process of the theoretical cutting edge arc in the step 1) is as follows: a reference circle with the radius R is cut by an inclined axis beta plane, an arc formed on the plane and a cylindrical surface is a theoretical cutting edge arc of a cutting edge, the theoretical cutting edge arc is a part of an ellipse and is a part with the minimum radian change on two sides of a short shaft, and as the inclination angle of the cutting edge is smaller, the replaced standard arc is closer to the theoretical cutting edge arc, so that the theoretical cutting edge arc is replaced by three standard arcs with the same end point.
Preferably, the conversion model in step 2) is:
in the formula:
r-the radius of the reference circle of the cutter head where the shear blade is located is mm;
beta-shear blade angle of inclination, degree;
2 b-the width of the cutter head where the shear blade is located is mm;
l-shear edge length, mm;
r-radius of arc of the substitute theoretical shear blade arc, mm.
Preferably, the shear force model of the circle shear in the step 3) is as follows:
in the formula:
p-shear, N;
K1-the coefficient of influence, constant, of the shear edge lateral clearance;
K3-coefficient of influence, constant, of sharpening of the cutting edge after use;
-relative incision rate, constant;
α1-shear edge shear angle, degree;
h-strip thickness, mm, of the sheared strip;
σb-sheared strip strength, MPa;
r-the arc radius of the arc of the substitute theoretical cutting edge, mm;
Δ1is the amount of overlap of the upper and lower cutting edges, mm.
Preferably, the shear force model of the circle shear in the step 3) is as follows:
in the formula:
p-shear, N;
-relative incision rate, constant;
α1-shear edge shear angle, degree;
h-strip thickness, mm, of the sheared strip;
σb-sheared strip strength, MPa;
r-the arc radius of the arc of the substitute theoretical cutting edge, mm;
Δ1is the amount of overlap of the upper and lower cutting edges, mm.
Preferably, the model of the cutting angle of the cutter in the step 4) is as follows:
in the formula:
α2-cutter head shear angle, degree;
h-strip thickness, mm, of the sheared strip;
-relative incision rate, constant;
r-the radius of the reference circle of the cutter head where the shear blade is located is mm;
Δ2the overlap of the upper and lower cutting edges, mm.
Preferably, the model of the shear torque of the cutter head in the step 5) is as follows:
M＝2PRsinα2
in the formula:
m-theoretical shear torque of the cutter head, Nm;
p-shear, N;
r-the radius of the reference circle of the cutter head where the shear blade is located is mm;
α2cutter head shear angle, degree.
Compared with the prior art, the invention has the advantages that:
(1) the invention carries out modeling on shearing torque, a theoretical shearing edge circular arc is a part of an ellipse and is a part with the minimum radian change on two sides of a short shaft according to the forming process of the shearing edge circular arc, the smaller the inclination angle of the shearing edge is, the closer the replaced standard circular arc is to the theoretical shearing edge circular arc, so the theoretical shearing edge circular arc is replaced by the standard circular arc with the same three end points, a conversion model is established according to the height difference between the circular arc highest point and the circular arc end point of the theoretical shearing edge circular arc and the height difference between the circular arc highest point and the circular arc end point of the standard circular arc, the circular arc radius replacing the theoretical shearing edge circular arc is obtained, then the shearing force is obtained through a shearing force model according to the circular arc radius replacing the theoretical shearing edge curve, then the shearing angle is obtained according to a cutter head shearing angle model, and finally the shearing torque of a, the modeling process is reasonable in design, the standard arc is used for replacing a theoretical shear blade arc, modeling of the shearing torque is carried out in different directions, the accuracy rate of the shearing torque is improved, the precision of the obtained shearing torque is high, and a theoretical basis is provided for designing the scrap shearing of the inclined shear blade;
(2) the torque model of the shearing torque of the edge-breaking shear of the inclined shear blade is solved, a complex model is converted into a simple model, the time is saved, the cost is low, and the flexibility is high;
(3) the shear torque modeling method is provided for the first time, and all data used in the modeling process are easy to obtain or can be obtained through query, so that the shear torque data cannot be influenced by data measurement errors in the process, and the calculation accuracy and the precision are high.
Drawings
FIG. 1 is a schematic structural diagram of a scrap shearing device of a modeling method of shearing torque of a bevel shear blade scrap shear according to the invention;
FIG. 2 is a schematic structural diagram of a cutter head assembly of the bevel blade scrap shear of the modeling method of the shearing torque of the bevel blade scrap shear of the invention;
FIG. 3 is a schematic diagram of a shearing edge of the scrap cutter in the modeling method of the shearing torque of the scrap cutter with the inclined cutting edge;
FIG. 4 is a theoretical shear blade arc schematic diagram of the modeling method of shear torque of the scrap shears with the inclined shear blades;
FIG. 5 is a top view of the present invention FIG. 4;
FIG. 6 is a diagram illustrating a theoretical shear blade arc simplified into a standard arc according to the modeling method for shear torque of the shearing mechanism of the bevel shear blade;
FIG. 7 is a schematic diagram of calculating a shearing angle of the scrap shears in the modeling method of the shearing torque of the scrap shears with the inclined shear blades.
1-a first cutter head assembly body, 2-a chute, 3-a second cutter head assembly body, 4-main transmission, 5-a base, 6-an upper cutter head, 7-a shear blade, 8-a pressing block, 9-a bolt and 10-a lower cutter head.
Detailed Description
The following describes embodiments of the present invention with reference to examples:
it should be noted that the structures, proportions, sizes, and other embodiments disclosed herein are illustrative only and are not intended to limit the scope of the invention, which is defined by the claims, since the scope of the invention is not limited by the specific structures, proportions, and dimensions, or otherwise, unless otherwise specified, since various modifications, changes in the proportions and variations thereof, can be made by those skilled in the art without departing from the spirit and scope of the invention.
In addition, the terms "upper", "lower", "left", "right", "middle" and "one" used in the present specification are for clarity of description, and are not intended to limit the scope of the present invention, and the relative relationship between the terms and the terms is not to be construed as a scope of the present invention.
Example 1
The invention discloses a modeling method for shearing torque of a bevel shear blade scrap shear, which comprises the following steps:
step 1) replacing a theoretical cutting edge arc by three standard arcs with the same end points according to the forming process of the theoretical cutting edge arc;
step 2) after a standard circular arc with three end points same as the theoretical cutting edge circular arc is obtained, establishing a conversion model according to the indexing circle radius of the cutter head where the cutting edge is located, the cutting edge inclination angle, the cutter head width where the cutting edge is located, the cutting edge length and the circular arc radius of the substitute theoretical cutting edge circular arc according to the fact that the height difference between the circular arc highest point and the circular arc end point of the theoretical cutting edge circular arc is the same as the height difference between the circular arc highest point and the circular arc end point of the standard circular arc, and obtaining the circular arc radius of the substitute theoretical cutting edge circular arc;
step 3) obtaining a shearing force through a disc shear shearing force model according to the arc radius of the substitute theory shear blade arc in the step 2);
step 4), obtaining a cutter head shearing angle according to the cutter head shearing angle model;
step 5) obtaining the theoretical shearing torque of the cutter head through a cutter head shearing torque model according to the shearing force of the step 3) and the cutter head shearing angle of the step 4);
and 6) designing a cutter head of the inclined shear blade scrap cutter according to the theoretical shearing torque obtained in the step 5), wherein the sheared torque of the cutter head of the inclined shear blade scrap cutter is larger than the theoretical shearing torque.
Example 2
The invention discloses a modeling method for shearing torque of a bevel shear blade scrap shear, which comprises the following steps:
step 1) replacing a theoretical cutting edge arc by three standard arcs with the same end points according to the forming process of the theoretical cutting edge arc;
step 2) after a standard circular arc with three end points same as the theoretical cutting edge circular arc is obtained, establishing a conversion model according to the indexing circle radius of the cutter head where the cutting edge is located, the cutting edge inclination angle, the cutter head width where the cutting edge is located, the cutting edge length and the circular arc radius of the substitute theoretical cutting edge circular arc according to the fact that the height difference between the circular arc highest point and the circular arc end point of the theoretical cutting edge circular arc is the same as the height difference between the circular arc highest point and the circular arc end point of the standard circular arc, and obtaining the circular arc radius of the substitute theoretical cutting edge circular arc;
step 3) obtaining a shearing force through a disc shear shearing force model according to the arc radius of the substitute theory shear blade arc in the step 2);
step 4), obtaining a cutter head shearing angle according to the cutter head shearing angle model;
step 5) obtaining the theoretical shearing torque of the cutter head through a cutter head shearing torque model according to the shearing force of the step 3) and the cutter head shearing angle of the step 4);
and 6) designing a cutter head of the inclined shear blade scrap cutter according to the theoretical shearing torque obtained in the step 5), wherein the sheared torque of the cutter head of the inclined shear blade scrap cutter is larger than the theoretical shearing torque.
Preferably, the forming process of the theoretical cutting edge arc in the step 1) is as follows: a reference circle with the radius R is cut by an inclined axis beta plane, an arc formed on the plane and a cylindrical surface is a theoretical cutting edge arc of a cutting edge, the theoretical cutting edge arc is a part of an ellipse and is a part with the minimum radian change on two sides of a short shaft, and as the inclination angle of the cutting edge is smaller, the replaced standard arc is closer to the theoretical cutting edge arc, so that the theoretical cutting edge arc is replaced by three standard arcs with the same end point.
Example 3
The invention discloses a modeling method for shearing torque of a bevel shear blade scrap shear, which comprises the following steps:
step 1) replacing a theoretical cutting edge arc by three standard arcs with the same end points according to the forming process of the theoretical cutting edge arc;
step 2) after a standard circular arc with three end points same as the theoretical cutting edge circular arc is obtained, establishing a conversion model according to the indexing circle radius of the cutter head where the cutting edge is located, the cutting edge inclination angle, the cutter head width where the cutting edge is located, the cutting edge length and the circular arc radius of the substitute theoretical cutting edge circular arc according to the fact that the height difference between the circular arc highest point and the circular arc end point of the theoretical cutting edge circular arc is the same as the height difference between the circular arc highest point and the circular arc end point of the standard circular arc, and obtaining the circular arc radius of the substitute theoretical cutting edge circular arc;
step 3) obtaining a shearing force through a disc shear shearing force model according to the arc radius of the substitute theory shear blade arc in the step 2);
step 4), obtaining a cutter head shearing angle according to the cutter head shearing angle model;
step 5) obtaining the theoretical shearing torque of the cutter head through a cutter head shearing torque model according to the shearing force of the step 3) and the cutter head shearing angle of the step 4);
and 6) designing a cutter head of the inclined shear blade scrap cutter according to the theoretical shearing torque obtained in the step 5), wherein the sheared torque of the cutter head of the inclined shear blade scrap cutter is larger than the theoretical shearing torque.
Preferably, the forming process of the theoretical cutting edge arc in the step 1) is as follows: a reference circle with the radius R is cut by an inclined axis beta plane, an arc formed on the plane and a cylindrical surface is a theoretical cutting edge arc of a cutting edge, the theoretical cutting edge arc is a part of an ellipse and is a part with the minimum radian change on two sides of a short shaft, and as the inclination angle of the cutting edge is smaller, the replaced standard arc is closer to the theoretical cutting edge arc, so that the theoretical cutting edge arc is replaced by three standard arcs with the same end point.
Preferably, the conversion model in step 2) is:
in the formula:
r-the radius of the reference circle of the cutter head where the shear blade is located is mm;
beta-shear blade angle of inclination, degree;
2 b-the width of the cutter head where the shear blade is located is mm;
m-length of the shear blade, mm;
r-radius of arc of the substitute theoretical shear blade arc, mm.
Example 4
The invention discloses a modeling method for shearing torque of a bevel shear blade scrap shear, which comprises the following steps:
step 1) replacing a theoretical cutting edge arc by three standard arcs with the same end points according to the forming process of the theoretical cutting edge arc;
step 2) after a standard circular arc with three end points same as the theoretical cutting edge circular arc is obtained, establishing a conversion model according to the indexing circle radius of the cutter head where the cutting edge is located, the cutting edge inclination angle, the cutter head width where the cutting edge is located, the cutting edge length and the circular arc radius of the substitute theoretical cutting edge circular arc according to the fact that the height difference between the circular arc highest point and the circular arc end point of the theoretical cutting edge circular arc is the same as the height difference between the circular arc highest point and the circular arc end point of the standard circular arc, and obtaining the circular arc radius of the substitute theoretical cutting edge circular arc;
step 3) obtaining a shearing force through a disc shear shearing force model according to the arc radius of the substitute theory shear blade arc in the step 2);
step 4), obtaining a cutter head shearing angle according to the cutter head shearing angle model;
step 5) obtaining the theoretical shearing torque of the cutter head through a cutter head shearing torque model according to the shearing force of the step 3) and the cutter head shearing angle of the step 4);
and 6) designing a cutter head of the inclined shear blade scrap cutter according to the theoretical shearing torque obtained in the step 5), wherein the sheared torque of the cutter head of the inclined shear blade scrap cutter is larger than the theoretical shearing torque.
Preferably, the forming process of the theoretical cutting edge arc in the step 1) is as follows: a reference circle with the radius R is cut by an inclined axis beta plane, an arc formed on the plane and a cylindrical surface is a theoretical cutting edge arc of a cutting edge, the theoretical cutting edge arc is a part of an ellipse and is a part with the minimum radian change on two sides of a short shaft, and as the inclination angle of the cutting edge is smaller, the replaced standard arc is closer to the theoretical cutting edge arc, so that the theoretical cutting edge arc is replaced by three standard arcs with the same end point.
Preferably, the conversion model in step 2) is:
in the formula:
r-the radius of the reference circle of the cutter head where the shear blade is located is mm;
beta-shear blade angle of inclination, degree;
2 b-the width of the cutter head where the shear blade is located is mm;
n-length of the cutting edge, mm;
r-radius of arc of the substitute theoretical shear blade arc, mm.
Preferably, the shear force model of the circle shear in the step 3) is as follows:
in the formula:
p-shear, N;
K1-the coefficient of influence, constant, of the shear edge lateral clearance;
K3-coefficient of influence, constant, of sharpening of the cutting edge after use;
-relative incision rate, constant;
α1-shear edge shear angle, degree;
h-strip thickness, mm, of the sheared strip;
σb-sheared strip strength, MPa;
r-the arc radius of the arc of the substitute theoretical cutting edge, mm;
Δ1is the amount of overlap of the upper and lower cutting edges, mm.
Preferably, the shear force model of the circle shear in the step 3) is as follows:
in the formula:
p-shear, N;
-relative incision rate, constant;
α1-shear edge shear angle, degree;
h-strip thickness, mm, of the sheared strip;
σb-sheared strip strength, MPa;
r-the arc radius of the arc of the substitute theoretical cutting edge, mm;
Δ1is the amount of overlap of the upper and lower cutting edges, mm.
Example 5
The invention discloses a modeling method for shearing torque of a bevel shear blade scrap shear, which comprises the following steps:
step 1) replacing a theoretical cutting edge arc by three standard arcs with the same end points according to the forming process of the theoretical cutting edge arc;
step 2) after a standard circular arc with three end points same as the theoretical cutting edge circular arc is obtained, establishing a conversion model according to the indexing circle radius of the cutter head where the cutting edge is located, the cutting edge inclination angle, the cutter head width where the cutting edge is located, the cutting edge length and the circular arc radius of the substitute theoretical cutting edge circular arc according to the fact that the height difference between the circular arc highest point and the circular arc end point of the theoretical cutting edge circular arc is the same as the height difference between the circular arc highest point and the circular arc end point of the standard circular arc, and obtaining the circular arc radius of the substitute theoretical cutting edge circular arc;
step 3) obtaining a shearing force through a disc shear shearing force model according to the arc radius of the substitute theory shear blade arc in the step 2);
step 4), obtaining a cutter head shearing angle according to the cutter head shearing angle model;
step 5) obtaining the theoretical shearing torque of the cutter head through a cutter head shearing torque model according to the shearing force of the step 3) and the cutter head shearing angle of the step 4);
and 6) designing a cutter head of the inclined shear blade scrap cutter according to the theoretical shearing torque obtained in the step 5), wherein the sheared torque of the cutter head of the inclined shear blade scrap cutter is larger than the theoretical shearing torque.
Preferably, the forming process of the theoretical cutting edge arc in the step 1) is as follows: a reference circle with the radius R is cut by an inclined axis beta plane, an arc formed on the plane and a cylindrical surface is a theoretical cutting edge arc of a cutting edge, the theoretical cutting edge arc is a part of an ellipse and is a part with the minimum radian change on two sides of a short shaft, and as the inclination angle of the cutting edge is smaller, the replaced standard arc is closer to the theoretical cutting edge arc, so that the theoretical cutting edge arc is replaced by three standard arcs with the same end point.
Preferably, the conversion model in step 2) is:
in the formula:
r-the radius of the reference circle of the cutter head where the shear blade is located is mm;
beta-shear blade angle of inclination, degree;
2 b-the width of the cutter head where the shear blade is located is mm;
o-shear edge length, mm;
r-radius of arc of the substitute theoretical shear blade arc, mm.
Preferably, the shear force model of the circle shear in the step 3) is as follows:
in the formula:
p-shear, N;
K1-the coefficient of influence, constant, of the shear edge lateral clearance;
K3-coefficient of influence, constant, of sharpening of the cutting edge after use;
-relative incision rate, constant;
α1-shear edge shear angle, degree;
h-strip thickness, mm, of the sheared strip;
σb-sheared strip strength, MPa;
r-the arc radius of the arc of the substitute theoretical cutting edge, mm;
Δ1is the amount of overlap of the upper and lower cutting edges, mm.
Preferably, the shear force model of the circle shear in the step 3) is as follows:
in the formula:
p-shear, N;
-relative incision rate, constant;
α1-shear edge shear angle, degree;
h-strip thickness, mm, of the sheared strip;
σb-sheared strip strength, MPa;
r-the arc radius of the arc of the substitute theoretical cutting edge, mm;
Δ1is the amount of overlap of the upper and lower cutting edges, mm.
Preferably, the model of the cutting angle of the cutter in the step 4) is as follows:
in the formula:
α2-cutter head shear angle, degree;
h-strip thickness, mm, of the sheared strip;
-relative incision rate, constant;
r-the radius of the reference circle of the cutter head where the shear blade is located is mm;
Δ2the overlap of the upper and lower cutting edges, mm.
Preferably, the model of the shear torque of the cutter head in the step 5) is as follows:
M＝2PRsinα2
in the formula:
m-theoretical shear torque of the cutter head, Nm;
p-shear, N;
r-the radius of the reference circle of the cutter head where the shear blade is located is mm;
α2cutter head shear angle, degree.
As shown in fig. 1, the existing scrap cutter device includes a first cutter head assembly body 1, a chute 2, a second cutter head assembly body 3, a main transmission 4 and a base 5, the main transmission 4 provides power for two, wherein the first cutter head assembly body 1 and the second cutter head assembly body 3 are respectively connected with the main transmission 4, and the first cutter head assembly body 1, the chute 2, the second cutter head assembly body 3 and the main transmission 4 are all arranged on the base 5.
As shown in fig. 2, the cutter head assembly of the existing oblique shear blade scrap cutter comprises an upper cutter head 6, a shear blade 7, a pressing block 8, a bolt 9 and a lower cutter head 10, wherein the shear blade 7 and the pressing block 8 are fixed on the upper cutter head 6 or the lower cutter head 10 through the bolt 9, the upper cutter head 6 and the lower cutter head 10 are arranged oppositely and have a certain inclination angle, and the shear blade 7 is not linear but circular arc.
As shown in fig. 3, the upper surface of the prior scrap cutter blade is arc-shaped, the theoretical arc is formed by cutting a reference circle with radius R by a plane with an inclined axis β, the curve formed by the plane and the cylinder on the cylindrical surface is the theoretical curve of the cutter blade, the curve is a part of an ellipse, wherein the length of the cutter blade is L, the height difference between the highest point of the arc and the end point of the arc is Δ t, the radius of the cutter head reference circle is R,
as shown in fig. 4 to 6, a schematic diagram of a process of simplifying a theoretical cutting edge arc into a standard arc is shown:
the calculation of the shearing torque of the edge-breaking shear of the inclined shear blade is related to the diameter of the reference circle of the cutter head, the inclination angle of the shear blade and the width of the cutter head.
In fig. 4, Δ t is the height difference between the highest point of the circular arc and the end point of the circular arc, R is the reference circle radius of the cutter head, and d is the length between the two end points of the circular arc; in fig. 5, L is the length of the shear blade, the inclination angle of the shear blade is β, and the width of the cutter head is 2 b; in fig. 6, Δ t is a height difference between a highest point of the arc and an end point of the arc, and r is an arc radius of the arc of the substitute theoretical cutting edge.
The arc of the cutting edge is a part of an ellipse, and is a part with the minimum radian change at two sides of the minor axis, the arc of the ellipse of the part can be replaced by three arcs with the same end point, the smaller the inclination angle of the cutting edge is, the closer the arc is to the arc of the ellipse, in order to meet the requirements of processing technology in engineering, the arc of the ellipse at the section of the cutting edge slowly changes, and the arc is used for replacing the arc of the ellipse.
Setting r as the radius of the arc replacing the elliptic arc, d as the length between two end points of the arc, and delta t as the height difference between the highest point of the arc and the end point of the arc:
d＝btanβ
establishing an equation:
the radius r of the arc of the substitute theoretical cutting edge can be determined from the above known conditions.
The shear force calculation formula of the disc shear is as follows:
kololefu formula:
noxali formula:
K1the influence coefficient of the side clearance of the cutting edge is generally 1.2-1.4;
K3the influence coefficient of the sharpening of the blade after use is generally 1.1-1.3;
-relative cut-in ratio, physical property of sheared material;
α1-a shear edge shear angle.
As shown in fig. 7, the shear angle α is calculated for the cutting edge in step 3)1And calculating cutter head shear angle α in step 4)2The calculation of (a):
is set to α2The cutter head shearing angle h is the strip thickness of the sheared strip, and the relative cut-in rate of the strip, delta2R is the indexing radius of the turntable obtained by scrap shearing for the overlapping amount of the upper and lower shearing blades
AEDB is the actual shear area:
the center distance of the cutter head is A-2R-delta2＝2Rcosα2+GF
GF is the distance between two points G and F
By the formula:
the cutter head shearing angle α can be obtained2Wherein the shear edge shear angle α1Is calculated from the cutter head shear angle α2The same is true.
Example 6
The index circle radius R of the cutter head is 225mm, the inclination angle β of the β shear blade is 20 degrees, the length L of the shear blade is 319.25mm, the width 2b of the cutter head is 300mm, the thickness h of the sheared strip is 6mm, and the strength sigma of the sheared strip is 6mmb800 MPa; the relative incision rate is found to be 0.3;
step 1) replacing a theoretical cutting edge arc by three standard arcs with the same end points according to the forming process of the theoretical cutting edge arc;
step 2) obtaining the arc radius r of the substitute theoretical shear blade arc of the shear blade according to the condition that the height difference between the arc highest point and the arc end point of the theoretical shear blade arc is the same as the height difference between the arc highest point and the arc end point of the standard arc, wherein the conversion model is as follows:
get r 1887 mm;
step 3) calculating the shearing force of the shearing force model of the disc shear
Noxali formula:
Δ1the amount of overlap of the upper and lower cutting edges is determined by the construction of the apparatus;
to obtain the shear angle α of the shear blade1＝0.078rad
P＝51222N
Step 4) calculating the cutter head shearing angle by the cutter head shearing angle model
Δ2＝0.5mm
α2＝0.17rad
Step 5) calculating theoretical shearing torque of the cutter by using the cutter shearing torque model
M＝2PRsinα2
M＝3899Nm
Step 6)) designing a cutter disc of the oblique-cutting-edge scrap cutter according to the theoretical shearing torque obtained in the step 5), wherein the shearing torque of the cutter disc of the oblique-cutting-edge scrap cutter is larger than the theoretical shearing torque 3899Nm when the cutter disc of the oblique-cutting-edge scrap cutter is designed.
The error between the cutterhead shearing torque obtained by the modeling method and the torque obtained by actual measurement is very small, so that the cutterhead shearing torque obtained by the method is high in accuracy and precision.
The principle of the invention is as follows:
the invention carries out modeling on shearing torque, a theoretical shearing edge circular arc is a part of an ellipse and is a part with the minimum radian change on two sides of a short shaft according to the forming process of the shearing edge circular arc, the smaller the inclination angle of the shearing edge is, the closer the replaced standard circular arc is to the theoretical shearing edge circular arc, so the theoretical shearing edge circular arc is replaced by the standard circular arc with the same three end points, a conversion model is established according to the height difference between the circular arc highest point and the circular arc end point of the theoretical shearing edge circular arc and the height difference between the circular arc highest point and the circular arc end point of the standard circular arc, the circular arc radius replacing the theoretical shearing edge circular arc is obtained, then the shearing force is obtained through a shearing force model according to the circular arc radius replacing the theoretical shearing edge curve, then the shearing angle is obtained according to a cutter head shearing angle model, and finally the shearing torque of a, the modeling process is reasonable in design, the standard arc is used for replacing the theoretical shear blade arc, the modeling of the shear torque is carried out in different directions, the shear torque accuracy is improved, the obtained shear torque is high in precision, and the theoretical basis is provided for the design of the oblique shear blade scrap shear.
The invention solves the torque model of the shearing torque of the edge-breaking shear of the inclined shear blade, converts a complex model into a simple model, saves time, and has low cost and high flexibility.
The invention provides a modeling method of the shearing torque for the first time, and each data used in the modeling process is easy to obtain or can be obtained through query, so that the shearing torque data is not influenced by the data measurement error in the process, the calculation accuracy is high, the precision is high, and the detailed description is given above on the preferred embodiment of the invention.
Many other changes and modifications can be made without departing from the spirit and scope of the invention. It is to be understood that the invention is not to be limited to the specific embodiments, but only by the scope of the appended claims. The components and structures of the present embodiments that are not described in detail are well known in the art and do not constitute essential structural elements or elements.
Claims (7)
1. A shear torque modeling method for a scrap shear with a bevel shear blade is characterized by comprising the following steps:
step 1) replacing a theoretical cutting edge arc by three standard arcs with the same end points according to the forming process of the theoretical cutting edge arc;
step 2) after a standard circular arc with three end points same as the theoretical cutting edge circular arc is obtained, establishing a conversion model according to the indexing circle radius of the cutter head where the cutting edge is located, the cutting edge inclination angle, the cutter head width where the cutting edge is located, the cutting edge length and the circular arc radius of the substitute theoretical cutting edge circular arc according to the fact that the height difference between the circular arc highest point and the circular arc end point of the theoretical cutting edge circular arc is the same as the height difference between the circular arc highest point and the circular arc end point of the standard circular arc, and obtaining the circular arc radius of the substitute theoretical cutting edge circular arc;
step 3) obtaining a shearing force through a disc shear shearing force model according to the arc radius of the substitute theory shear blade arc in the step 2);
step 4), obtaining a cutter head shearing angle according to the cutter head shearing angle model;
step 5) obtaining the theoretical shearing torque of the cutter head through a cutter head shearing torque model according to the shearing force of the step 3) and the cutter head shearing angle of the step 4);
and 6) designing a cutter head of the inclined shear blade scrap cutter according to the theoretical shearing torque obtained in the step 5), wherein the sheared torque of the cutter head of the inclined shear blade scrap cutter is larger than the theoretical shearing torque.
2. The modeling method of shear torque of a bevel shear blade scrap shear according to claim 1, wherein:
the forming process of the theoretical cutting edge arc in the step 1) is as follows: a reference circle with the radius R is cut by an inclined axis beta plane, an arc formed on the plane and a cylindrical surface is a theoretical cutting edge arc of a cutting edge, the theoretical cutting edge arc is a part of an ellipse and is a part with the minimum radian change on two sides of a short shaft, and as the inclination angle of the cutting edge is smaller, the replaced standard arc is closer to the theoretical cutting edge arc, so that the theoretical cutting edge arc is replaced by three standard arcs with the same end point.
3. The modeling method of shear torque of a bevel shear blade scrap shear according to claim 1, wherein:
the conversion model in the step 2) is as follows:
in the formula:
r-the radius of the reference circle of the cutter head where the shear blade is located is mm;
beta-shear blade angle of inclination, degree;
2 b-the width of the cutter head where the shear blade is located is mm;
l-shear edge length, mm;
r-radius of arc of the substitute theoretical shear blade arc, mm.
4. The modeling method of shear torque of a bevel shear blade scrap shear according to claim 1, wherein:
the shear force model of the disc shear in the step 3) is as follows:
in the formula:
p-shear, N;
K1-the coefficient of influence, constant, of the shear edge lateral clearance;
K3coefficient of influence of sharpening of the cutting edge after useConstant;
-relative incision rate, constant;
α1-shear edge shear angle, degree;
h-strip thickness, mm, of the sheared strip;
σb-sheared strip strength, MPa;
r-the arc radius of the arc of the substitute theoretical cutting edge, mm;
Δ1is the amount of overlap of the upper and lower cutting edges, mm.
5. The modeling method of shear torque of a bevel shear blade scrap shear according to claim 1, wherein:
the shear force model of the disc shear in the step 3) is as follows:
in the formula:
p-shear, N;
-relative incision rate, constant;
α1-shear edge shear angle, degree;
h-strip thickness, mm, of the sheared strip;
σb-sheared strip strength, MPa;
r-the arc radius of the arc of the substitute theoretical cutting edge, mm;
Δ1is the amount of overlap of the upper and lower cutting edges, mm.
6. The modeling method of shear torque of a bevel shear blade scrap shear according to claim 1, wherein:
the cutter head shearing angle model in the step 4) is as follows:
in the formula:
α2-cutter head shear angle, degree;
h-strip thickness, mm, of the sheared strip;
-relative incision rate, constant;
r-the radius of the reference circle of the cutter head where the shear blade is located is mm;
Δ2the overlap of the upper and lower cutting edges, mm.
7. The modeling method of shear torque of a bevel shear blade scrap shear according to claim 1, wherein:
the cutter shearing torque model in the step 5) is as follows:
M＝2PRsinα2
in the formula:
m-theoretical shear torque of the cutter head, Nm;
p-shear, N;
r-the radius of the reference circle of the cutter head where the shear blade is located is mm;
α2cutter head shear angle, degree.
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| WO2000040361A1 (en) * | 1998-12-30 | 2000-07-13 | Shanghai Baosteel Group Corporation | A method for determining parameters of a rolling shear mechanism according to technical requirements |
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| WO2000040361A1 (en) * | 1998-12-30 | 2000-07-13 | Shanghai Baosteel Group Corporation | A method for determining parameters of a rolling shear mechanism according to technical requirements |
| CN103862094A (en) * | 2012-12-12 | 2014-06-18 | 攀钢集团攀枝花钢钒有限公司 | Shearing method by using circle shear and shearing method for hot-rolled steel strip |
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