CN104421150A

CN104421150A - Spiral rotor and method for generating tooth profile thereof

Info

Publication number: CN104421150A
Application number: CN201310468740.3A
Authority: CN
Inventors: 林敬渊; 董能瑞
Original assignee: Yatai Fuji Seiki Ltd Co ltd
Current assignee: Yatai Fuji Seiki Ltd Co ltd
Priority date: 2013-09-06
Filing date: 2013-10-09
Publication date: 2015-03-18
Anticipated expiration: 2033-10-09
Also published as: TWI539078B; TW201510361A; CN104421150B

Abstract

The invention discloses a spiral rotor and a method for creating a tooth shape. The tooth shape is set relative to a top circle, a pitch circle and a bottom circle. The spiral rotor includes a first curve, a second curve and a bottom circle. The third curve. The second curve is connected to the first curve using the base circle, and the second curve is formed in a cycloidal manner by a point of the top circle. The third curve is connected to the first curve using a pitch circle and connected to the second curve using a vertex circle. The third curve is used to generate the first curve in a conjugate and mirror manner. The third curve is formed on an end surface of a cylinder. and connects the pitch circle and the base circle. The cylinder is generated by the top circle. A spiral groove is provided on the surface of the cylinder and connected to the end surface of the cylinder. The depth of the spiral groove is the ratio of the radius of the top circle and the radius of the pitch circle. Difference.

Description

The creation method of helical rotor and profile of tooth thereof

Technical field

The present invention relates to a kind of creation method of rotor and profile of tooth thereof, be particularly useful in the vacuum side helical rotor of pump and the creation method of profile of tooth thereof about a kind of.

Background technique

Generally speaking, the inside of vacuum side pump board is provided with the rotor of two corresponding engagements, is sucked by fluid, then sent by the opposite side of described fluid by rotor by relatively rotating of two rotors from the side of rotor.Therefore, the fluid being positioned at the described side of rotor just can be extracted out from described side, and reaches effect of vacuum.

But, the profile of tooth formed due to above-mentioned helical rotor does not consider the actual operation parameter adding cutter needed for man-hour in the design phase, therefore when above-mentioned helical rotor adds man-hour actual, often because processing not easily increases the reject ratio of helical rotor, even cause cutter cannot meet designed profile of tooth and original tooth Shape Design need be readjusted, and then elongate production time-histories and be unfavorable for that board is manufactured.

Summary of the invention

Therefore, the invention provides a kind of vacuum that is useful in and help the helical rotor of pump board and the creation method of profile of tooth thereof, to solve the problem.

The present invention discloses a kind of helical rotor, and its profile of tooth is that setting is round relative to a tip circle, a pitch circle and an end, and described helical rotor includes one first curve, one second curve and one the 3rd curve.Described second curve utilizes circle of the described end to be connected to described first curve, and described second curve is by a bit being formed in the mode of cycloid on described tip circle.Described 3rd curve utilizes described pitch circle to be connected to described first curve respectively and utilizes described tip circle to be connected to described second curve, described 3rd curve is used for producing described first curve in the mode of conjugation and mirror, the end face that described 3rd curve is formed in a cylinder connects described pitch circle and circle of the described end, wherein said cylinder utilizes described tip circle to generate, one helical groove is arranged on the surface of described cylinder and is connected to the described end face of described cylinder, and the degree of depth of described helical groove is the difference of described tip circle radius and described Pitch radius.

The present invention discloses described first curve negotiating one formation curve further and produces in the mode of conjugation, described in described 3rd curve negotiating, formation curve produces in the mode of mirror, and the described end face that wherein said formation curve is formed in described cylinder connects described pitch circle and described tip circle.

The present invention discloses described formation curve further and is same as described 3rd curve, and described formation curve differs 180 degree with described 3rd curve.

The width that the present invention discloses described helical groove is further the half of a helical pitch of described helical rotor and the difference of a specific width.

The sidewall that the present invention discloses described helical groove is further an inclined-plane, the side on described inclined-plane is formed with one first globoidal structure being connected to described periphery, and the opposite side on described inclined-plane is formed with one second globoidal structure being connected to described helical groove bottom surface.

The present invention discloses described 3rd curve further and includes an inner arc curve, one first limit arc and a Second Edge arc.The corresponding described inclined-plane of described inner arc curve.Corresponding described first globoidal structure of described first limit arc, described first limit arc is used for connecting described inner arc curve and described pitch circle.Corresponding described second globoidal structure of described Second Edge arc, described Second Edge arc is used for connecting described inner arc curve and described tip circle.

The present invention discloses a kind of method of tooth profile of screw rotor of creating further, and it includes a tip circle, a pitch circle, end circle and a helical pitch according to predetermined space and the corresponding described helical rotor of suction amount setting; Described tip circle is utilized to generate a cylinder; A helical groove is formed on the surface of described cylinder; Connect described helical groove in an end face of described cylinder; Acquisition connects a formation curve of described pitch circle and circle of the described end on the end surface; Described formation curve is utilized to generate one first curve in the mode of conjugation; Utilize and described tip circle a bit forms one second curve in the mode of cycloid; Described formation curve is utilized to generate one the 3rd curve differing 180 degree with described 3rd curve in the mode of mirror; And utilize circle of the described end to connect described first curve to be respectively connected described second curve with described second curve, described tip circle and to be connected described 3rd curve and described first curve with described 3rd curve and described pitch circle.

The present invention openly arranges a helical groove further and includes the difference that the degree of depth setting described helical groove is described tip circle radius and described Pitch radius on the surface of described cylinder; And the pitch setting described helical groove is described helical pitch.

The present invention openly arranges a helical groove further, and include the width setting described helical groove further on the surface of described cylinder be the half of described helical pitch and the difference of a specific width.

The surface that the present invention is disclosed in described cylinder further forms a helical groove and includes and form an inclined-plane at a sidewall of described helical groove; One first globoidal structure being connected to described periphery is formed in the side on described inclined-plane; And the opposite side on described inclined-plane forms one second globoidal structure being connected to described helical groove bottom surface.

The present invention openly utilizes described formation curve to generate one first curve in the mode of conjugation to include the rotor engaged corresponding to the described helical rotor by described formation curve and rotate a special angle further; Complete by described formation curve after the described rotor engaged corresponding to described helical rotor rotates described special angle, more described formation curve is rotated described special angle relative to described helical rotor; Complete described formation curve after described helical rotor rotates described special angle, produce the envelope corresponding to described formation curve; And capture the curve of described envelope Jie between a pitch circle and end circle of the described rotor engaged corresponding to described helical rotor.

The present invention openly utilizes described formation curve to generate one the 3rd curve in the mode of mirror to include horizontal for described formation curve mirror further; And complete after horizontal for described formation curve mirror, then by vertical for described formation curve mirror.

The present invention openly utilizes described formation curve to generate one the 3rd curve in the mode of mirror to include vertical for described formation curve mirror further; And complete after vertical for described formation curve mirror, then by horizontal for described formation curve mirror.

In sum, the width design of helical groove of the present invention adds the cutter parameters that adopts man-hour according to actual and set, and the inclined-plane of helical groove, the first globoidal structure and the second globoidal structure contribute to cutter adding can more successfully process for sidewall and corner man-hour.Therefore, helical rotor of the present invention, except having advantage easy to process, more can avoid the problem that cutter cannot be processed designed profile of tooth, and then shortens production time-histories and be conducive to the board manufacturing.Can be further understood by following detailed Description Of The Invention and appended accompanying drawing about the advantages and spirit of the present invention.

Accompanying drawing explanation

Fig. 1 is the element schematic of embodiment of the present invention vacuum side pump board.

Fig. 2 is the generalized section of the profile of tooth of the embodiment of the present invention first helical rotor.

Fig. 3 is the element schematic of the embodiment of the present invention first helical rotor.

Fig. 4 is that the present invention creates the flow chart of method of profile of tooth of the first helical rotor.

Fig. 5 is the schematic diagram of embodiment of the present invention tip circle, pitch circle and end circle.

Fig. 6 is the element schematic of embodiment of the present invention cylinder.

Fig. 7 is the generalized section of the profile of tooth of embodiment of the present invention formation curve and the first helical rotor.

Fig. 8 is the flow chart that the embodiment of the present invention forms helical groove.

Fig. 9 is the generalized section of cylinder shown in Fig. 6.

Figure 10 is that the embodiment of the present invention utilizes formation curve to generate the flow chart of the first curve in the mode of conjugation.

Figure 11 to Figure 14 is respectively formation curve generates the first curve decomposing schematic representation in the mode of conjugation.

Wherein, description of reference numerals is as follows:

3 vacuum side pump boards

30 bodies

32 first helical rotors

33 second helical rotors

34 first curves

36 second curves

38 the 3rd curves

40 cylinders

381 inner arc curves

383 first limit arcs

385 Second Edge arcs

401 helical grooves

403 end faces

405 formation curves

407 inclined-planes

4070 first globoidal structures

4072 second globoidal structures

T tip circle

P pitch circle

Circle at the bottom of R

A area

D helical pitch

E envelope

C1 center

C2 specified point

RS, PS, TS circular arc

Tr, Pr radius

X specific width

θ special angle

Step 100 ~ 118,200 ~ 212,300 ~ 308

Embodiment

Refer to Fig. 1, Fig. 1 is the element schematic of embodiment of the present invention vacuum side pump board 3.As shown in Figure 1, vacuum side pump board 3 includes body 30 and one first helical rotor 32 and one second helical rotor 33.First helical rotor 32 and the second helical rotor 33 are installed in body 30, and the profile of tooth of the first helical rotor 32 is identical and correspond to the profile of tooth of the second helical rotor 33.Therefore, first helical rotor 32 is just engageable in the second helical rotor 33, when the first helical rotor 32 and the second helical rotor 33 relatively rotate, fluid just can suck from the side of the first helical rotor 32 and the second helical rotor 33, again the opposite side of described fluid by the first helical rotor 32 and the second helical rotor 33 is sent, use the effect reaching vacuum.Profile of tooth due to the first helical rotor 32 is same as the profile of tooth of the second helical rotor 33, for the sake of clarity, is only described for the structural design of the profile of tooth of the first helical rotor 32 below.

Refer to Fig. 2, Fig. 2 is the generalized section of the profile of tooth of the embodiment of the present invention first helical rotor 32.As shown in Figure 2, the first helical rotor 32 can help the predetermined space of pump board 3 to set centre distance between itself and the second helical rotor 33 according to vacuum, uses a tip circle T, the pitch circle P and end circle R that set corresponding first helical rotor 32.As shown in Figure 2, tip circle T, pitch circle P and end circle R are arranged all with one heart, and the diameter of tip circle T is greater than the diameter of pitch circle P, and the diameter of pitch circle P is greater than the diameter of end circle R.In other words, tip circle T, pitch circle P and circle R position, the end on same concentric circle, and arrange from large to small according to the order of tip circle T, pitch circle P and end circle R on described concentric circle.

From the above, tip circle T and the first helical rotor 32 profile of tooth can around in an area A(Fig. 2 with the oblique line person of illustrating).Refer to Fig. 3, Fig. 3 is the element schematic of the embodiment of the present invention first helical rotor 32.As shown in Figure 3, the first helical rotor 32 has a helical pitch D, the contribution that the product of itself and area A helps the suction amount of pump board 3 to produce for single helical rotor (i.e. the first helical rotor 32) to vacuum.Generally speaking, vacuum side pump board 3 has two helical rotors, and in other words, the product of helical pitch D and area A can be used to define the suction amount that vacuum helps pump board 3.In sum, the predetermined space of pump board 3 and suction amount is helped can to set tip circle T, pitch circle P, the end circle R and helical pitch D of corresponding first helical rotor 32 according to vacuum actually.

As shown in Figure 2, the profile of tooth of the first helical rotor 32 includes one first curve 34,1 second curve 36 and one the 3rd curve 38.Second curve 36 utilizes a circular arc R S of end circle R to be connected to the first curve 34.3rd curve 38 utilizes a circular arc PS of pitch circle P to be connected to the first curve 34 respectively and utilizes a circular arc TS of tip circle T to be connected to the second curve 36.In addition, the 3rd curve 38 includes inner arc curve 381,1 first limit arc 383 and a Second Edge arc 385.First limit arc 383 is used for connecting the circular arc PS of inner arc curve 381 and pitch circle P, and Second Edge arc 385 is used for connecting the circular arc TS of inner arc curve 381 and tip circle T.

Refer to Fig. 4, Fig. 4 is that the present invention creates the flow chart of method of the first helical rotor 32 profile of tooth.Fig. 4 comprises the following step:

Step 100: tip circle T, the pitch circle P, the end circle R and helical pitch D that set corresponding first helical rotor 32 according to predetermined space and suction amount, wherein Fig. 5 is the schematic diagram of embodiment of the present invention tip circle T, pitch circle P and end circle R.

Step 102: utilize tip circle T to generate a cylinder 40, wherein Fig. 6 is the element schematic of embodiment of the present invention cylinder 40.

Step 104: form a helical groove 401 on the surface of cylinder 40.

Step 106: connect helical groove 401 in an end face 403 of cylinder 40.

Step 108: acquisition connects a formation curve 405 of pitch circle P and end circle R on end face 403.

Step 110: utilize formation curve 405 to generate the first curve 34 in the mode of conjugation.

Step 112: utilize and tip circle T a bit forms the second curve 36 in the mode of cycloid.

Step 114: utilize formation curve 405 to generate the 3rd curve 38 differing 180 degree with formation curve 405 in the mode of mirror.

Step 116: utilize end circle R to connect the first curve 34 respectively and be connected the second curve 36 with the second curve 36, tip circle T and be connected the 3rd curve 38 and the first curve 34 with the 3rd curve 38 and pitch circle P.

Step 118: terminate.

Be described for above-mentioned steps at this.First, as shown in Fig. 2, Fig. 3 and Fig. 5, according to tip circle T, the pitch circle P of the predetermined space of vacuum side pump board 3 and corresponding first helical rotor 32 of suction amount setting, end circle R and helical pitch D(step 100).Then, tip circle T is utilized to generate cylinder 40(step 102 as shown in Figure 6).Helical groove 401(step 104 is formed on the surface of cylinder 40), and make helical groove 401 be connected to the end face 403(step 106 of cylinder 40).So, cylinder 40 end face 403 just fechtable connect the formation curve 405(step 108 of pitch circle P and end circle R), in other words, on the end face 403 that formation curve 405 is formed in cylinder 40 and connection pitch circle P and tip circle T.

Refer to Fig. 7, Fig. 7 is the generalized section of embodiment of the present invention formation curve 405 and the first helical rotor 32 profile of tooth.As shown in Figure 7, after completing the drafting of formation curve 405, by the side of formation curve 405 refigure in the profile of tooth of the first helical rotor 32.Then, formation curve 405 is utilized to generate the first curve 34(step 110 in the mode of conjugation).In addition, utilize and tip circle T a bit forms the second curve 36(step 112 in the mode of cycloid).Finally, formation curve 405 is utilized to generate the 3rd curve 38(step 114 differing 180 degree with formation curve 405 in the mode of mirror).

It is worth mentioning that, utilize formation curve 405 to generate the 3rd curve 38 in the mode of mirror and include first by after horizontal for formation curve 405 mirror, then by vertical for formation curve 405 mirror to generate the 3rd curve 38.But the order utilizing formation curve 405 to generate the 3rd curve 38 in the mode of mirror is not limited with above-mentioned.For example, also can first by after vertical for formation curve 405 mirror, then by horizontal for formation curve 405 mirror to generate the 3rd curve 38.From the above, the 3rd curve 38 produced through horizontal mirror and vertical mirror respectively by formation curve 405, and therefore the 3rd curve 38 is same as formation curve 405, and the 3rd curve 38 differs 180 degree with formation curve 405.That is, the 3rd curve 38 also rotates 180 degree by formation curve 405 and obtains.

In sum, the first curve 34 is produced in the mode of conjugation by formation curve 405, and the 3rd curve 38 is produced in the mode of mirror by formation curve 405, and the 3rd curve 38 is same as formation curve 405.In other words, actually, after the 3rd curve 38 also can be utilized to produce formation curve 405 in the mode of mirror, recycle the formation curve 405 generated by the 3rd curve 38 mirror and produce the first curve 34 in the mode of conjugation.That is, the 3rd curve 38 can be used to produce the first curve 34 in the mode of conjugation and mirror.

After the drafting completing the first curve 34, second curve 36 and the 3rd curve 38, then utilize the circular arc R S of end circle R to connect the first curve 34 to be respectively connected the second curve 36 with the circular arc TS of the second curve 36, tip circle T and to be connected the 3rd curve 38 and the first curve 34 with the circular arc PS of the 3rd curve 38 and pitch circle P.By this, the closed curve be made up of above-mentioned circular arc R S, TS, PS, the first curve 34, second curve 36 and the 3rd curve 38 is the section of the first helical rotor 32 profile of tooth.

Forming step (step 104) below for helical groove 401 is described in detail.Refer to Fig. 8, Fig. 8 is the flow chart that the embodiment of the present invention forms helical groove 401, and Fig. 8 comprises the following step:

Step 200: the degree of depth of setting helical groove 401 is the difference of the radius Tr of tip circle T and the radius Pr of pitch circle P.

Step 202: the pitch setting described helical groove 401 is helical pitch D.

Step 204: the width of setting helical groove 401 is the half of helical pitch D and the difference of a specific width X.Step 206: form an inclined-plane 407 at a sidewall of helical groove 401.

Step 208: form one first globoidal structure 4070 being connected to cylinder 40 surface in the side on inclined-plane 407.Step 210: the opposite side on inclined-plane 407 forms one second globoidal structure 4072 being connected to helical groove 401 bottom surface.

Step 212: terminate.

See also Fig. 9, Fig. 9 is the generalized section of cylinder 40 shown in Fig. 6.As shown in Figures 6 to 9, first, the described degree of depth of setting helical groove 401 is the difference (step 200) of the radius Tr of tip circle T and the radius Pr of pitch circle P, the pitch of setting helical groove 401 is helical pitch D(step 202), and the width of setting helical groove 401 is the half of helical pitch D and the difference (step 204) of specific width X.In this embodiment, specific width X is 1/4th of helical pitch D, but does not limit by this.Actually, specific width X adds the cutter needed for man-hour according to actual and set.After completing above-mentioned setting, the mode of cutting is utilized to form helical groove 401 on the surface of cylinder 40.In other words, because the actual cutter parameters added needed for man-hour is taken into account when designing by helical rotor of the present invention, therefore helical rotor of the present invention has advantage easy to process, and can avoid the problem that cutter cannot be processed designed profile of tooth.

Further, for making helical rotor of the present invention more can be conducive to processing, be that helical groove 401 imports following design.First, inclined-plane 407(step 206 is formed at a sidewall of helical groove 401).Then, then in the side on inclined-plane 407 formed and be connected to the first globoidal structure 4070(step 208 on cylinder 40 surface (i.e. tip circle T)) and opposite side formation on inclined-plane 407 be connected to the second globoidal structure 4072(step 210 of helical groove 401 bottom surface).Above-mentioned design can make cutter can more successfully process for sidewall and corner man-hour adding.

After completing above-mentioned steps, then helical groove 401 is connected to the end face 403 of cylinder 40, uses and produce formation curve 405(as shown in Figure 6 on end face 403).It is worth mentioning that, when helical groove 401 is connected to the end face 403 of cylinder 40, inclined-plane 407, first globoidal structure 4070 and the second globoidal structure 4072 form the 3rd curve 38(and formation curve 405 respectively) inner arc curve 381, first limit arc 383 and Second Edge arc 385.In other words, inclined-plane 407, first globoidal structure 4070 of helical groove 401 and the second globoidal structure 4072 inner arc curve 381, the first limit arc 383 of corresponding 3rd curve 38 and Second Edge arc 385 respectively.

Be described in detail for the step (step 110) utilizing formation curve 405 to generate the first curve 34 in the mode of conjugation below.Refer to Figure 10, Figure 10 is that the embodiment of the present invention utilizes formation curve 405 to generate the flow chart of the first curve 34 in the mode of conjugation.Figure 10 comprises the following step:

Step 300: formation curve 405 is rotated a special angle relative to the center C1 of the first helical rotor 32.

Step 302: complete by formation curve 405 after the center C1 of the first helical rotor 32 rotates a special angle θ, then formation curve 405 is rotated special angle θ relative to a specified point C2 of the second helical rotor 33.

Step 304: complete by formation curve 405 after the specified point C2 of the second helical rotor 33 rotates special angle θ, produces the envelope E corresponding to formation curve 405.

Step 306: the curve of acquisition envelope E between the pitch circle P and end circle R of the first helical rotor 32.

Step 308: terminate.

See also Figure 11 to Figure 14, Figure 11 to Figure 14 is respectively formation curve 405 generates the first curve 34 decomposing schematic representation in the mode of conjugation.As shown in FIG. 10 to 14, formation curve 405 is as shown in figure 11 rotated position (step 300) shown in special angle θ to Figure 12 relative to the center C1 of the first helical rotor 32, again formation curve 405 is rotated special angle θ (step 302) relative to the specified point C2 of the second helical rotor 33, make position shown in formation curve 405 Figure 13.Repeat above-mentioned steps, make formation curve 405 produce envelope E(step 304 as shown in figure 14).Then, the curve of acquisition envelope E between the pitch circle P and end circle R of the first helical rotor 32, described curve is the first curve 34.

Compared to prior art, the width design of helical groove of the present invention adds the cutter parameters that adopts man-hour according to actual and set, and the inclined-plane of helical groove, the first globoidal structure and the second globoidal structure contribute to cutter adding can more successfully process for sidewall and corner man-hour.Therefore, helical rotor of the present invention, except having advantage easy to process, more can avoid the problem that cutter cannot be processed designed profile of tooth, and then shortens production time-histories and be conducive to the board manufacturing.

The foregoing is only the preferred embodiments of the present invention, be not limited to the present invention, for a person skilled in the art, the present invention can have various modifications and variations.Within the spirit and principles in the present invention all, any amendment done, equivalent replacement, improvement etc., all should be included within protection scope of the present invention.

Claims

1. A helical rotor whose tooth profile is set relative to a top circle, a pitch circle and a bottom circle, characterized in that the helical rotor comprises:

a first curve;

a second curve connected to the first curve by means of the bottom circle, the second curve being formed by a point of the top circle in a cycloidal fashion; and

a third curve connected to the first curve by the pitch circle and connected to the second curve by the apex circle respectively, the third curve is used to generate the The first curve, the third curve is formed on one end surface of a cylinder and connects the pitch circle and the bottom circle, wherein the cylinder is generated by the top circle, and a helical groove is arranged on the The surface of the cylinder is connected to the end surface of the cylinder, and the depth of the spiral groove is the difference between the radius of the top circle and the radius of the pitch circle.

2. The helical rotor according to claim 1, wherein the first curve is generated in a conjugated manner by a generating curve, and the third curve is generated in a mirrored manner by the generating curve, wherein The generating curve is formed on the end face of the cylinder and connects the pitch circle and the tip circle.

3. The screw rotor according to claim 2, wherein the generated curve is the same as the third curve, and the generated curve is one hundred and eighty degrees different from the third curve.

4. The helical rotor according to claim 1, wherein the width of the helical groove is the difference between half of a lead of the helical rotor and a specific width.

5. The helical rotor according to claim 1, wherein one side wall of the helical groove is an inclined plane, and one side of the inclined plane is formed with a first arc connected to the surface of the cylinder surface structure, and a second arc surface structure connected to the bottom surface of the helical groove is formed on the other side of the inclined surface.

6. The screw rotor according to claim 5, wherein the third curve comprises:

an inner arc curve corresponding to the slope;

a first side arc, which corresponds to the first arc surface structure, and the first side arc is used to connect the inner arc curve and the pitch circle; and

A second side arc, which corresponds to the second arc surface structure, and the second side arc is used to connect the inner arc and the top circle.

7. A method for creating a helical rotor tooth profile, characterized in that the method comprises:

Setting a top circle, a pitch circle, a bottom circle and a lead corresponding to the helical rotor according to the predetermined space and suction and displacement;

generating a cylinder using the top circle;

forming a helical groove on the surface of the cylinder;

The helical groove is connected to one end surface of the cylinder;

extracting a generated curve connecting the pitch circle and the bottom circle on the end surface;

generating a first curve in a conjugate manner using the generating curve;

forming a second curve in a cycloidal manner using a point of the apex circle;

using the generated curve to generate a third curve that is one hundred and eighty degrees different from the generated curve in a mirrored manner; and

Using the bottom circle to connect the first curve and the second curve, the top circle to connect the second curve to the third curve, and the pitch circle to connect the third curve to the first curve a curve.

8. The method of claim 7, wherein forming the helical groove on the surface of the cylinder comprises:

setting the depth of the helical groove to be the difference between the tip circle radius and the pitch circle radius; and

The pitch of the helical groove is set as the lead.

9. The method of claim 8, wherein forming the helical groove on the surface of the cylinder further comprises:

The width of the helical groove is set to be the difference between half of the lead and a specific width.

10. The method of claim 7, wherein forming the helical groove on the surface of the cylinder comprises:

A slope is formed on a side wall of the spiral groove;

forming a first arc structure connected to the cylindrical surface on one side of the slope; and

A second arc surface structure connected to the bottom surface of the helical groove is formed on the other side of the slope.

11. The method according to claim 7, characterized in that, using said generating curve to generate in a conjugate manner

The first curve includes:

rotating the generated curve by a specific angle relative to a rotor corresponding to the helical rotor;

After the generated curve is rotated by the specific angle relative to the rotor corresponding to the helical rotor, then the generated curve is rotated by the specific angle relative to the helical rotor;

After the generated curve is rotated by the specific angle relative to the helical rotor, an envelope curve corresponding to the generated curve is generated; and

A curve whose envelope line is between a pitch circle and a bottom circle of the rotor corresponding to the helical rotor is extracted is extracted.

12. The method according to claim 7, wherein generating the third curve in a mirrored manner using the generating curve comprises:

mirroring said resulting curve horizontally; and

After the horizontal mirroring of the generated curve is completed, the generated curve is mirrored vertically.

13. The method according to claim 7, characterized in that, using the generating curve to generate in a mirroring manner

The third curve includes:

vertically mirroring the resulting curve; and

After the vertical mirroring of the generated curve is completed, the generated curve is mirrored horizontally.