WO2015143584A1

WO2015143584A1 - Constant-angle scissors

Info

Publication number: WO2015143584A1
Application number: PCT/CN2014/000399
Authority: WO
Inventors: 谢培树
Original assignee: 谢培树
Priority date: 2014-03-24
Filing date: 2014-04-14
Publication date: 2015-10-01
Also published as: CN104942836A; WO2015143850A1

Abstract

A pair of constant-angle scissors. Angles to the central axis line at any scissor blade point are approximately equal to a constant value. The constant-angle scissors not only can increase the average stress for all of the scissor blade points, but also can prevent the utilization rate of the scissor blades from being reduced. The scissors allows the angle to the central axis to be increased as much as possible with respect to the friction coefficient of a target object. The constant-angle scissors provided with a specific angle to the central axis allows for effortless and stable cutting of a specific target object, thus significantly optimizing the application performance of the constant-angle scissors.

Description

Constant angle scissors

Technical field

[001] The present invention relates to a pair of scissors, and more particularly to a scissors blade. Background technique

[002] According to the front view of the conventional scissors shown in Fig. 1, the conventional scissors includes seven components: a blade body (la), a blade body (2a), a blade edge (lb), a blade edge (2b), a connecting shaft (3a), and a shank (lc). ) and the handle (2c). The blade (lb) is on the upper part of the blade (la) and the blade (2b) is on the upper part of the blade (2a). The shank (lc) is at the lower part of the blade (la) and the shank (2c) is at the lower part of the blade (2a). The edge of the blade (lb) and the blade (2b) are straight segments and are symmetrical along the central axis. For ease of explanation, the following proper nouns are defined according to the main view of the ordinary scissors.

[003] Target: The object that the scissors cut. Say

[004] Distance: Euclidean distance.

[005] Connection point: Connect the center point of the axis. Its position is shown as the center point of (3a) in Figure 1.

[006] Blade: The sharp part of the knife. Its shape is shown in Figure 1 (lb book).

[007] Blade point: A point on the edge of the blade.

[008] Blade intersection: The intersection of 2 edge edges. Its position is as shown in (1a) of Fig. 1.

[009] Centerline: A ray that passes through the intersection of the blades from the point of attachment. Its position is shown in (4b) of Figure 1.

[010] Tangent: A ray that is tangent to the edge of a blade from the intersection of the blade and that is less than or equal to the central axis. Its

2 The position is (4c) in Figure 1.

[011] Shear angle: The angle formed by the two cut rays at the intersection of the blade, and which is less than or equal to r. Its position is shown in Figure 1 (4d).

[012] Axis angle: The positive angle between the central axis of a certain blade point and the tangent rays passing through that point, and it is less than . Its position is shown in Figure 1.

2

(4e). ·

[013] Intersection radius: The distance between the intersection of the blade and the connection point.

[014] Intra-intersection point: When the shear angle is less than or equal to; Γ, the intersection of the blade that satisfies the minimum radius of intersection is the in-intersection point.

[015] Diplomacy: When the shear angle is less than or equal to Γ, the intersection of the blade that satisfies the radius of the intersection is the diplomatic point.

[016] Blade starting point: The edge of the blade edge that has the smallest distance from the joint. Its position is shown as (4f) in Figure 1.

[017] End of the blade: The edge of the blade edge that has the largest distance from the connection point. Its position is shown in Figure 1 (4g).

[018] Center Axis Short Distance: The distance between the connection point and the start of the blade.

[019] Center Axis Long Distance: The distance between the connection point and the end of the blade.

[020] Shear distance: The value of the long axis of the center axis minus the short distance of the center axis.

[021] Blade Utilization: The ratio of the shear distance to the long axis of the center axis.

[022] The edge of the blade of a conventional scissors is a straight line segment, and its central axis angle changes significantly as it rotates. Therefore, ordinary scissors belong to variable angle scissors. The rotary shearing process of the ordinary scissors is equivalent to the outward movement of the blade intersection.

[023] As shown in Figure 2, AO C and AO ) E are part of the blade of a common scissors, 2 edge edges (the intersection of ^ and O is O, OA is part of the central axis, and the edge of the blade is at O 2 The strip ray is O, OM. Because O and OD are straight segments, O covers O5, and OM covers OD. It is the mid-axis angle. The pentagon OGHIJ is the cross-section of the target under shear, and its edge GH Parallel to Q/J. Because O and O> are symmetric along 04, line J 7 is perpendicular to 04. The midpoint of line segment JG is. Obvious line segment <3⁄4: perpendicular to JG. Known points and points, The symbol represents the distance of the sum. |JG| is the thickness of the target. The shear plane of the target is the triangle AOGJ, and the direction of the blade pressure F is perpendicular to O. Since the thickness of the target |JG| is small, it is approximately equal to a constant value at the shear triangle ΔΟΟ/. According to the mechanics theory, the blade pressure F will produce a component force F' perpendicular to the line segment O in one direction. The relationship between the two is as follows:

[024] F' = F cos ZAOB (2.1)

[025] According to the plane geometry theory, it is easy to calculate the area of the right triangle AOGJ S

\JG\-\OK \JG - cot ZAOB

[026] (2.2)

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[027] According to the theory of material mechanics, the average shear stress produced by the shear plane OGJ is:

[028] F = ^ (2.3)

S

[029] Substituting (2.1), (2.2) into (2.3), you can get:

p_4F sinZAOB

[030] (2.4)

a \ ^JG f

[031] Assuming that the allowable shear stress of the target is r, the sufficient conditions for successful shearing of the scissors are: [032] F>T (2.5)

[033] Substituting (2.4) into (2.5) gives:

[035] When the target is continuously cut with ordinary scissors, 4O is changed from large to small, and the minimum blade pressure F is also increased from small to large. Therefore, the minimum cutting edge pressure required for ordinary scissors is always gradually increased, and the user's effort is gradually increased.

[036] Assume that the center angle of the scissors blade at the end of the blade is α. If α is small, it is difficult for the scissors to cut high-strength materials, and the application range is significantly reduced.

[037] If α is large, the mid-axis angle change interval is [α, ^). This is discussed below in accordance with Figure 3.

[038] Figure 3 shows the normal scissors rotation process, where is the joint point, A is the starting point of the cutting edge, the end point of the cutting edge, the ray ^ is the central axis, and A is the inner intersection point, which is the diplomatic point. Edge of the blade first rotates to the line segment 3⁄4Α, then rotates to the line segment G^H^

Sin OjH!^

[040] ilOA lOAl, the formula (2.6) is equivalent to the following formula: [041] (2. 7)

Sin O!H,^

[042] The ratio of the shear distance IH'Al to the center axis long distance IHiQl is -

\Η _λ Ο, \ \Η _χ Ο _χ \ l^sin OjH,^ l~3⁄4T = T3⁄43⁄4 = ^sin ^^ ' The formula (2. 8) is equivalent to the following:

[046] According to the above assumption, it is known that Zq^C^ Q^, if "increase, the ~^| in the formula (2.9) is reduced, thereby reducing the knife.

I

Blade utilization reduces the application performance of the scissors.

[047] In summary, the mid-axis angle cannot increase both the average stress and the blade utilization. Therefore, the minimum center axis angle of the ordinary scissors has a narrow optimization space, which makes it difficult to optimize the overall performance of the ordinary scissors. Summary of the invention

[048] The present invention is directed to a constant angle scissors and a method of manufacturing the same. Constant angle scissors not only increase the average stress at all cutting edges, but also reduce the blade utilization.

[049] The features of the constant angle scissors are explained herein in conjunction with FIG. As shown in Figure 5, the constant angle scissors consists of 7 components: blade body (la), blade body (2a), blade edge (lb), blade edge (2b), connecting shaft (3a), tool holder (lc) and tool holder (2c). The blade (lb) is on the upper part of the blade (la), the blade (2b) is on the upper part of the blade (2a), the shank (lc) is on the lower part of the blade (la), and the shank (2c) is on the lower part of the blade (2a); The edges of lb) and blade (2b) are curved and symmetrical along the central axis; the edge of the blade (lb) is Φ, and the connection point of the connecting shaft (3a) is (9; (lb) the starting point of the upper blade is the corpse, (lb) The end point of the upper cutting edge is the point O as the origin of the 2-dimensional coordinate system, and the F-axis of the 2-dimensional coordinate system is established by the straight line PO; the direction of the Γ axis is equal to the direction of the ray; the crossing point β is a straight line perpendicular to the axis, Its intersection with the axis is R; the origin O is one axis perpendicular to the Γ axis, the direction of the axis is equal to the direction of the ray ^; the ray is rotated counterclockwise by the arc 2; r, every ^ radians, it is used The intersection of Φ is taken as a sample of Φ,

60

Finally, the sample set is obtained in turn - ^ρ^, , , ύ^; the subscript 样本' of the sample α, representing the rotation of the ^ rotation is ^, calculated in turn

60

The central axis angle α,. of the sample α,. gives the set of central axis angles = ;

- < " ^ is always established.

1 ' ¹ 60 [050] FIG. 4 shows the rotational trajectory of the constant angle scissors, the edge of which is a curved section. When the edge of the blade β ₂ / _{2 is} first rotated to the curve segment and then rotated to the curve segment G ₇ H ₇ , the central axis angle of any blade point on the constant angle scissors is approximately equal to a constant value. The parameters of Figure 4 and Figure 3 have the following relationship:

, Z0 ₂ B ₂ C ₂ = O _x B _x C _x

[051] For a constant angle scissors, the mid-axis angle of any blade point on it is approximately equal to a constant value. Therefore, as long as the center axis angle is set, all the blade points on the constant angle scissors can generate a large average stress.

[052] According to the theory of planar geometry, it is easy to infer: |E ₂ O ₂ | = |H ₁ O ₁ |. Therefore, it can be derived:

[056] Because! ^ ^^卜 So the above formula can be derived

HA

[062] >

H ₂ 0 ₂ HA

[063] Therefore, the edge utilization of the constant angle scissors is greater than that of the conventional scissors.

[064] In summary, the constant angle scissors can increase the average stress of all the cutting edge points and avoid reducing the blade utilization.

[065] The constant angle scissors in the present invention adopt the following technical solutions:

[066] 1. Establish an edge equation of the blade edge (lb), or establish an edge equation of the blade edge (2b);

[067] 2. Using the symmetry method, establish an edge equation for another blade;

[068] 3. Set the appropriate equation parameters for the strength and friction coefficient of the target;

[069] 4. Determine the starting point of one cutting edge and the end point of one cutting edge on the edge equation of the cutting edge (lb) or the cutting edge (2b), and regard the closed interval of the two-point polar angle as the domain of the edge of the cutting edge. On the blade edge equation, the curve outside the blade edge definition domain is deleted;

[070] 5. Using the symmetry method, one edge of the blade and one end of the blade are determined on the edge equation of the other blade, and the closed interval of the two-point polar angle constraint is regarded as the domain of the edge of the blade. On the blade edge equation, the curve outside the blade edge definition domain is deleted; [071] 6. According to the edge equation of the blade (lb) and the blade (2b), the blade (lb) and the blade (2b) are machined on the blade.

[072] The present invention has the following advantages:

[073] 1. Increases the average stress of all cutting edges and reduces the blade utilization.

[074] 2. The central axis angle can be increased as much as possible for the friction coefficient of the target. Setting a constant angle scissors with a specific center angle can save a specific target with low effort and stability, and significantly optimize the application performance of the constant angle scissors.

W diagram

[075] Figure 1 is a front view of a conventional scissors.

[076] Figure 2 is a cross-sectional view of a conventional scissors cutting article.

[077] Figure 3 is a diagram showing the blade utilization of ordinary scissors.

[078] Figure 4 is a diagram of the blade utilization of the constant angle scissors.

[079] Figure 5 is a front view of a constant angle scissors.

[080] Figure 6 is a Cartesian equation for the edge of the blade (lb).

[081] Figure 7 is a polar coordinate equation for the edge of the blade (lb). Specific implementation method

DETAILED DESCRIPTION OF THE INVENTION A preferred embodiment of the invention is provided below and the invention is described in detail.

[083] As shown in FIG. 5, the constant angle scissors embodiment includes seven components: a blade body (la), a blade body (2a), a blade edge (lb), a blade edge (2b), a connecting shaft (3a), and a tool holder (lc). And the shank (2c); the blade (lb) is on the upper part of the blade (la), the blade (2b) is on the upper part of the blade (2a); the shank (lc) is on the lower part of the blade (la), and the shank (2c) is on the blade (2a) Lower part; the edges of the blade (lb) and the blade (2b) are curved segments and are symmetrical along the central axis.

[084] The technical specification for the constant angle scissors embodiment is - | = 0, which exceeds the technical specifications required by the constant angle scissors | < ^. First, we create a Cartesian coordinate system as shown in Figure 6. The origin is O, the horizontal axis is the axis, and the vertical axis is the axis. Next, establish the edge equation of the blade (lb) or the blade (2b). In this embodiment, the edge equation of the blade edge (lb) is first established, and the edge equation of the blade edge (2b) is established. Some variables are defined below according to Figure 6.

[085] The origin O represents the constant angle scissors connection point, the curve Ψ represents the edge of the blade 4, the point represents the intersection of the blade, the ray ^ 5 represents the central axis, the straight line represents the tangent of the curve Ψ at the point, and 3 is the intersection of the tangent and the axis of the point The angle formed by the ray ^ 5 and the axis is a, the angle formed by the ray ^ 3 and the axis is 0, and the angle of the central axis is 0 = -or. According to the definition of the central axis, e (0, ) holds.

[086] Since the constant angle scissors embodiment is intended to satisfy - | = 0, its edge equation of the blade satisfies the following sufficient conditions:

[087] When the constant angle scissors blade rotates arbitrarily, the central axis angle at any point above it is equal to a constant value.

[088] As shown in FIG. 6, the point coordinates are (χ, . According to the central axis angle definition, 0 G (O, ) holds.

[089] Here, the edge equation of the blade is established as a polar coordinate equation. Define r as the polar path, define α as the polar angle, and set the following polar coordinate transformation:

[091] The blade edge equation is r(a) = 0. Define the character M, "for any two positive odd numbers. The following is a discussion of the form of the edge equation of the blade based on the values of α and ?.

[092] (1) or≠^~ and yff:

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[095] According to (5.2), (5.1):

[096] tan^ =—

r cosa] d{r- m )l da

[097]

d r-co )l da n r sina + cosa

[098] tan^ =—

r -cos -r-smcr

•tana + r

=> tan =— (5.3) r- r - tan a

[100] According to (5.3), available:

n ^f -tanor + r

[101] tan -tana =— tana

r - r - tan a

r Λχα -r- (r ^r · tan ar- tan ² a

[102] = tan — tan = n ^ r + tan a

[103] = tan - tan a = (5.4) r'-r■ tan

[104] According to (5.3), available -

, _{Ω +} r' tma + r ₊

[105] tan yff · tan a =— tana

r -r-tana r tan + r tan

[106] (5.5) r ^f - -tana r - tan a + r- tan or

[107] =>l + tan>ff tana = l +

a taim r - r - tan a + r tan a--r- tan a

[108] 1 + tan ^ · tan a =

'- -tancr r' + r'-tan ² a

[100] 1 + tan yff · tan a = (5.6) ■ r · tan a According to the plane geometry theory and the triangular identity, we can get:

Tan<9 = tan(^-a) n tmB- tan a

=>tan^ = (5.7)

1 + tan yff · tan a According to (5.4), (5.6), (5.7), we can get: r + r-tan a

105] tan/9 =

r' + r'- tan ² ar(l + tan a

106] =^ tan^ =

r'(l + tan ² a

107] tan^ =―

108] = — = cot6>

109] — dr = cotO · da

111] => r -a cotO + C 112] =i> r- e (5.8)

113] The parameter Ce(—∞, +QO) in equation (5.8) represents an arbitrary constant. When α ≠ ^^ and ≠ · ^, equation (5.8) is an angular curve.

114] (2) « _≠ and =

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115] According to (5.1), available:

116] / = ^

Dx

, , d( sma)/ da

118] = {-

d^r-cosa)/ da

―, . ' · sin o + r * cos a

119] => y =

r' cosa-r sm' a

, r' - tan λ-r , ,

120] =>/ = (5.9)

r, 一Γ· tan a [121] Substituting (5.8) into (5.9), you can get: e ^amW+c -cotO -tana + e ^a∞t9+c

[122] y

e ^a∞te+c -cotO- e ^acote+c -tana

F-cot^+C

Cot^-tanor + e'

[123] =>y =■ (5.10)

e ^aQOie+c -{cote-tma)

[124] Substituting "=-6" into (5.10) gives: e ^a∞te+c ^οΧθ-\Άηα + β ^ααΛθ+(

[125]

~ e ^acot ^ -(cot^-cot^) ~

[126] =^ = oo η·π

[127] So at point r (where, the tangent of the curve r = e ^ac °w ^+t exists and is a vertical tangent. At this point, β

2 Established. At the same time, α = ·^—6> is also true. Therefore, α = /?— 6> holds, ie — α = ^ holds. So when ≠ ^^ and ; 3 = ^, equation (5.8) is still a constant angle curve.

[128] (3) α = Άβ^

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[129] Substituting (5.8) into (5.3), available:

• cotfl+C

Cot^ tanor + e'

[130] ta ^ =

e ^aeoie+c -(cote-tana) e ^{a cote+c} -cot0 + e ^{a coie+c} -cota

[131] = ta /ff = (5.11)

• cot Θ ' cot -e ^l

Τη·π

[132] will be = = 2nd generation (5.11), available:

[134] => tan0 = -cot β

[135] => tan^ = -tan β m-π

[136] => tan6' = tan β-

[137] (5.12) [138] Substituting = ^^ into (5. 12), you can get:

2

[139] β- α = θ

[140] So when CT = ^ and ;, the equation (5. 8) is still a constant angle curve.

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[141] In summary, equation (5.8) is the blade edge (lb) edge equation. Where the parameter 0 e (O, ) represents the central axis angle constant, the parameter

C e (;-∞, +00) stands for any constant. Parameter 0 is used to adjust the mid-axis angle, and parameter C is used to adjust the shape of the equation curve. The curve in Figure 7 is the graph of equation (5.8).

[142] Assume that the starting point of the blade and the end of the cutting edge of equation (5. 8) are ^, ), (r ₂ , a ₂ ), respectively. According to the definition, £3⁄4 < « _{2 is} established. Since the equation (5.8) is a strictly increasing function, η </" ₂ is also true. At this time, the shear distance is 0 ₂ - ^), so the following blade utilization is obtained:

[143]

r ₂ r ₂

[144] \ - e (5. 13)

R2

[145] When fixed, Equation (5. 13) can increase the blade utilization by reducing (A - α ₂ ).

[146] Take 0 = as an example. In this case, set = - , then H« 0.85. The blade utilization rate at this time is still large.

8 4 r ₂

[147] Equation (5.13) shows that if the increase and decrease of α ₂ in the interval (0, ), the average stress of the cross section of the target increases, and the blade utilization is still large.

[148] With the axis as the axis of symmetry and the symmetry of the edge equation of the blade (lb), the edge equation of the blade (2b) is obtained -

[150] Using the symmetry method, it is also possible to first establish the edge equation of the blade edge (2b) and then establish the edge equation of the blade edge (lb).

[151] The central axis angle of the constant angle scissors is not as large as possible, for the following reasons:

[152] 1. Increasing the mid-axis angle of the constant-angle scissors increases the average stress at all cutting points, but also increases the blade thrust at all cutting points. The blade thrust moves the target, destroying the stable shear.

[153] 2. The friction coefficient of the target produces friction, which prevents the target from being pushed by the blade.

[154] Therefore, in the present embodiment, for the friction coefficient of the target, one parameter 0 and one suitable parameter are set as large as possible.

[155] Determine one blade starting point 05, ) and one cutting edge end point O ₂ , or ₂ ) on the edge of the cutting edge (lb), and regard the closed interval bound by the two-point polar angle as the domain of the edge of the cutting edge . On the edge equation of the edge (lb), the curve outside the blade edge definition field is deleted. [156] Using the symmetrical method, one edge starting point and one cutting edge end point symmetrical to the cutting edge (lb) are determined on the edge of the cutting edge (2b). Thus, at the edge of the blade (2b), the starting point of the blade is -, or, and the edge of the blade at the edge of the blade (2b) is (r ₂ , - α ₂ ). The closed interval [- , - ] constrained by the two-point polar angle is taken as the domain of the edge of the blade. On the edge equation of the edge (2b), the curve outside the blade edge definition domain is deleted.

[157] Finally, according to the edge equation of the blade (lb) and the blade (2b), the blade (lb) and the blade (2b) are machined on the blade.

[158] In summary, the constant angle scissors can increase the average stress of all the cutting edge points and avoid reducing the blade utilization. Setting the constant angle scissors for a specific mid-axis angle saves the force and stability of the specific target and significantly optimizes the application performance of the constant-angle scissors. In addition, it is also possible to add serrations at the edge of the blade of the constant angle scissors to increase the coefficient of friction.

The above description and images have disclosed preferred embodiments of the invention. This example is not to be taken as limiting the invention. The scope of protection of the present invention is not limited to this embodiment.

Claims

Claim

1. A constant angle scissors comprising 7 components: blade body (la), blade body (2a), blade edge (lb), blade edge (2b), connecting shaft (3a), tool holder (lc) and holder (2c) The blade (lb) is on the upper part of the blade (la), the blade edge (2b) is on the upper part of the blade body (2a), the tool holder (lc) is on the lower part of the blade body (la), and the tool holder (2c) is on the lower part of the blade body (2a); The edge of the blade (lb) and the blade (2b) is a curved segment and is symmetrical along the central axis. The edge of the blade (lb) is Φ, the connection point of the connecting shaft (3a) is Ο, and (b) the starting point of the blade is the corpse. (lb) The end point of the upper edge is β, the point O is used as the origin of the 2-dimensional coordinate system, and the y-axis of the 2-dimensional coordinate system is established by the line »<, the direction of the y-axis is equal to the direction of the ray, and the ρ is made one point. Vertical to

The straight line of the 7-axis, whose intersection with the F-axis is ?, passes through the origin O as an axis perpendicular to the Γ axis, the direction of the axis is equal to the direction of the ray ^, and the ray is rotated counterclockwise by 2?r, every ^ In the case of radians, use the intersection with Φ as the sample of Φ, and finally get the sample in turn.

60

The set = { _βι , _β2 , _α3 , , the subscript of the sample represents the arc of the ^ rotation is ^, and the middle axis angle a of the sample α, is calculated in turn to obtain the set of the central axis angle = {C^ C^A, , the calculation set The average value of {α,}, then |α,. _ ^ < ^ is constant.

2. The constant angle scissors according to claim 1, wherein: the edge of the blade edge (lb) satisfies the polar coordinate equation ^ « = '"^ ^{+ £} :, the edge of the blade edge (2b) satisfies the polar coordinate equation r = e ⁽ The common variables of the two equations are: α, r ; the common parameters of the two equations are: θ, the parameter (0, ^ represents the central axis constant, and the parameter C e (_∞, +∞) represents Arbitrary constants; parameters are used to adjust the mid-axis angle, and parameter C is used to adjust the shape of the equation curve.

3. A constant angle scissors according to claim 1 or 2, wherein: both blade edge lengths are greater than 5 cm.

4. A constant angle scissors according to claim 1 or 2, wherein: the serration is increased at the edge of any blade to increase the coefficient of friction.

5. A scissor blade, characterized in that: the connecting point of the connecting shaft is the origin of the polar coordinate system, and the continuous blade edge length satisfying the polar coordinate equation r = e ^α ' ^co w ^{+ e} is greater than 5 cm; the parameters of the equation For: θ, C ; Parameter 5> e (0, ) represents the central axis angle constant, the parameter C _e (- _∞ , +00) represents any constant; the parameter is used to adjust the central axis angle, and the parameter C is used to adjust the equation curve. shape.

6. A scissors blade, characterized in that: the connection point of the connecting shaft is the origin of the polar coordinate system, and the polar coordinate equation r = e ⁽ ^where a continuous blade edge length is greater than 5 cm; the parameter of the equation is : θ, C ; Parameter 0 e (O, ) represents the central axis angle constant, parameter

(-∞, +∞) stands for any constant; parameter 0 is used to adjust the mid-axis angle, and parameter C is used to adjust the shape of the equation curve.

7. A method of manufacturing the constant angle scissors of claim 1 comprising the steps of:

(1) Using the polar coordinate equation re^t^ ⁷ as the edge equation of the blade (lb), using the polar coordinate equation r = e ⁽ ^{-e) cote+e} as the edge equation of the blade (2b); the common of these two equations The variables are: α, r; the common parameters of the two equations are: 0, C; the parameter S e (0,^) represents the central axis angle constant, and the parameter (-∞, +∞) represents any constant: Parameter 0 is used for Adjust the mid-axis angle, parameter C is used to adjust the shape of the equation curve;

(2) Set the appropriate equation parameters 0 and C for the strength and friction coefficient of the target; (3) Determine the starting point of one cutting edge and the end point of one cutting edge on the edge equation of the cutting edge (lb) or the cutting edge (2b), and regard the closed interval bound by the two-point polar angle as the domain of the edge of the cutting edge; On the edge equation of the blade, the curve outside the defined edge of the blade edge is deleted;

(4) Using the symmetry method, determine the starting point of one cutting edge and the end point of one cutting edge on the edge equation of the other cutting edge, and regard the closed interval of the two-point polar angle constraint as the domain of the edge of the cutting edge; On the top, delete the curve outside the edge definition domain;

(5) According to the edge equation of the blade edge (lb) and the blade edge (2b), the blade edge (lb) and the blade edge (2b) are machined on the blade body.