CN100351522C

CN100351522C - Screw rotor

Info

Publication number: CN100351522C
Application number: CNB028288726A
Authority: CN
Inventors: 阿部俊敬
Original assignee: Hokuetsu Industries Co Ltd
Current assignee: Hokuetsu Industries Co Ltd
Priority date: 2002-06-24
Filing date: 2002-06-24
Publication date: 2007-11-28
Anticipated expiration: 2022-06-24
Also published as: WO2004001229A1; JP4271654B2; AU2002346203A1; CN1628216A; KR20050010753A; JPWO2004001229A1

Abstract

The present invention provides a screw rotor which is characterized in that the rectangular cross sections of the shafts of a pair of screw rotors are in a shape that the curvature radius of the rectangular cross section of a shaft at one corner (14) in corners (14, 15) formed by both ends (A, B) of a top curve (13') of a tooth and two side curves (18', 19') of the tooth is gradually reduced in a bulged direction, and the shape of the side curves of the tooth from the corner (14) to a bottom curve (17') of the tooth is used for forming a curve of the corner (14) of the screw rotor. Thereby, no interference exists in the tooth space of the screw rotor, sealing performance is favorable, processing is easy, and generated air holes are small.

Description

Helical rotor

Technical field

The present invention relates to use the helical rotor in screw fluid machines such as screw compressor or vacuum pump and other volute pump, particularly the profile of tooth of this helical rotor.

Background technique

In recent years, in order to improve screw compressor or vacuum pump performance, carried out many research, exploitation about the profile of tooth of helical rotor, the profile of tooth of this helical rotor also develops into the multiple profile of tooth that comprises the complex curve combination.

The profile of tooth of this helical rotor, for example at the real helical rotor 10 that discloses in the clear 63-14884 communique of opening of Japan, it is shown in Figure 10 (A), the profile of tooth in the cross section on axial direction of helical rotor is done squarely, be formed with smooth Topland 13 and tooth bottom surface 17, and from the

flank

18,19 and the orthogonal axe at the two

end part

24,25 of two

bight

14,15 to tooth bottom surfaces of the axial direction of Topland 13.

As mentioned above, the Japan of the profile of tooth that is square in the cross section is real to open in the helical rotor 10 that clear 63-14884 communique disclosed, tooth top is formed with face (Topland 13), so the sealing of carrying out between cylinder barrel inner face and this Topland 13 then becomes face closure, the seal height, therefore, can suitably prevent to leak to another action space that is positioned at low voltage side from the gap of the Topland of inner wall of cylinder and helical rotor 10, can improve compression efficiency at the compressed fluid of an action space.

On the other hand, the helical rotor 10 that forms like this, shown in Figure 10 (B), the profile of tooth of the axle right-angle cross-section of helical rotor, Topland curve 13 ' with the profile that constitutes Topland 13, constitute the tooth bottom surface curve 17 ' of the profile of tooth bottom surface 17, and connect the flank upper thread 18 ' of the profile that is used for constituting flank 18 between described Topland curve and the described tooth bottom surface curve, and make described flank upper thread 18 ' form the straight line shape that extends to the peripheral direction of helical rotor, and the bight 14 that forms between described Topland curve 13 ' and the described flank upper thread 18 ' is formed the approximate right angle shape.

Rotate synchronously if having 2

helical rotor

10a, 10b of this profile of tooth, then when the engagement of the tooth of 2

helical rotor

10a, 10b, just bight 14 and the flank line 18 ' that is formed at another helical rotor are interfered.Therefore, otch is made in the bight 14 of helical rotor, prevented this interference (with reference to Figure 10 (C)).

But, two

helical rotor

10a, 10b, for example when the engagement shown in Figure 10 (B), shown in dotted line among Figure 10 (B), if this bight 14 is being formed with the state of otch, the sealing of action space then reduces, engagement by

helical rotor

10a, 10b, make originally independently that the chamber is action space A and action space B,, make compressed fluid leak to the action space that is positioned at low voltage side owing to this otch is communicated with.Therefore, there is the problem that compression efficiency reduces in this helical rotor.

In order to address this is that, the helical rotor that has a kind of Japanese Patent Publication 64-8193 communique to be disclosed can prevent interference of tooth and bring into play good sealing property (with reference to Figure 11).

In this helical rotor, shown in Figure 11 (B), the shape of the flank curve 18 ' of the axle right-angle cross-section of helical rotor can obtain roughly to seal completely by being formed with a bit drawn trochoidal curve in the bight 14 that is connected Topland curve 13 ' and flank curve 18 ' that this spiral changes another helical rotor of engagement.

The helical rotor that Japanese Patent Publication 64-8193 communique is disclosed can obtain roughly to seal completely in theory, if but want in the helical rotor of this formation, to guarantee sealing completely, bight 14 must form sharp keen bladed (edge shape).

But, sharp keen bladed is processed in bight 14, very difficult on the reality, when for example making this helical rotor by cutting, then 14 meetings produce a large amount of burrs in the bight, carry out the chamfering in bight etc. in order to remove this burr, then because this chamfering, the bladed of burr with bight 14 reamed, so the same sealing of action space that makes reduces when above-mentioned otch is set.

And, for bight 14 is formed sharp keen shape, must come the end 24 of the formed tooth of another helical rotor bottom surface 17 that this bight 14 is meshed to process with instrument with sharp keen shape, the part of the sharp keen shape of this instrument forms breach easily, even small breach or wearing and tearing, also can't correctly carry out the cutting of rotor, must often change or sharpening etc. again.

And, to specially permit No. 2904719 communique in Japan and disclose a kind of helical rotor is arranged, the bight formation circular arc with the axle right-angle cross-section of helical rotor improves sealing simultaneously.

This helical rotor forms the bight 14 of 2 helical rotors by circular arc, and the bight 14 that forms this circular arc forms the flank curve with the flank of another helical rotor of this helical rotor engagement.

In the helical rotor that so forms, between two rotors, can not produce interference, and improve the sealing of action space.

But, because with bight 14 as above-mentioned formation circular arc, therefore, when crest line 33 parts in inner wall of cylinder stand facing each other the bight of two rotors, then form bigger pore (with reference to Figure 12), by this pore each action space of adjacency is communicated with, so exist the fluid of compression to leak to the action space that is positioned at low voltage side and the problem that reduces compression efficiency.

And the leakage of this compressed fluid is not only to betide formed bight 14 between Topland 13 and the flank 18, betides the gap of 31 of Topland 13 and inner wall of cylinder yet.

Be provided with in Topland 13 and 31 of inner wall of cylinder and make helical rotor rotate necessary MIN gap, and the thermal expansion amount of considering helical rotor is set internal diameter of cylinder, thus, even in the running of screw fluid machine, Topland 13 does not contact with inner wall of cylinder 31 yet.But, the Topland 13 of helical rotor is not to produce impartial thermal expansion amount with respect to axis of rotation, so internal diameter of cylinder is set at the position according to the thermal expansion amount maximum, therefore in the position of thermal expansion amount maximum part in addition, Topland 13 is big with the gap of inner wall of cylinder 31, be easy to generate the leakage of fluid by the gap of this part,, then can further improve the operating efficiency of screw fluid machines such as vacuum pump if the helical rotor that can prevent aptly in the leakage of this part can be provided.

In addition, in document CN2358252Y, disclosed a kind of screw rod, but this screw rod can not make the gap between Topland and inner wall of cylinder narrow as far as possible.

Summary of the invention

The object of the present invention is to provide a kind of helical rotor that can solve the shortcoming of above-mentioned prior art, its profile of tooth can make the between cog of two helical rotors not interfere, sealing is good, and processing is than being easier to, and can make the pore that is produced little to practical negligible degree.

In order to achieve the above object, the present invention relates to a kind of helical rotor, this helical rotor is used to make a pair of helical rotor to mesh the screw machine that rotation sucked and discharged fluid in the opposite mode of Hand of spiral, this helical rotor is included in the described a pair of helical rotor, wherein, the profile of tooth of each of described a pair of helical rotor right-angle cross-section possesses: constitute the Topland curve of Topland profile, it is by being constituted with the axis of rotation of the helical rotor circular arc by the predetermined radius at center; Constitute the tooth bottom surface curve of tooth bottom profile, it is made of and radius concentric with the described Topland curve circular arc less than the radius of described Topland curve; And 2 flank curves of formation flank profile, it is formed between described Topland curve and the described tooth bottom surface curve, wherein, side with formed bight between the two ends of described Topland curve and described 2 the flank curves, curve between a end by connecting described Topland curve and the end of described flank curve forms, it is characterized in that: will connect the curve between the end of end of described Topland curve and flank curve, form the curve that reduces gradually from the projected direction radius of curvature of an end towards described bight of Topland curve, and the flank curve that makes this bight link tooth bottom surface curve becomes the curve that is generated by a side in the described bight of another helical rotor in the described a pair of helical rotor.

The invention still further relates to a kind of helical rotor, this helical rotor is used to make a pair of helical rotor to mesh the screw machine that rotation sucked and discharged fluid in the opposite mode of Hand of spiral, this helical rotor is included in the described a pair of helical rotor, wherein, the profile of tooth of each of described a pair of helical rotor right-angle cross-section possesses: constitute the Topland curve of Topland profile, it is by being constituted with the axis of rotation of the helical rotor circular arc by the predetermined radius at center; Constitute the tooth bottom surface curve of tooth bottom profile, it is made of and radius concentric with the Topland curve circular arc less than the radius of Topland curve; And 2 flank curves of the described flank profile of formation, it is formed between described Topland curve and the described tooth bottom surface curve, wherein, side with formed bight between the two ends of described Topland curve and 2 the described flank curves, curve between a end by connecting described Topland curve and the end of described flank curve forms, it is characterized in that: will connect the described curve between the end of end of described Topland curve and described flank curve, form the curve that reduces gradually from the projected direction radius of curvature of an end towards described bight of described Topland curve, and the flank curve that makes this bight link described tooth bottom surface curve becomes the curve that is generated by a side in the described bight of another helical rotor in the described a pair of helical rotor, and at least one side in the described a pair of helical rotor is in 90 ° to 180 ° the scope at center with the axis of rotation that the Topland curvilinerar figure is formed in described helical rotor.

Description of drawings

Fig. 1 is the sectional top view that possesses the vacuum pump of helical rotor of the present invention.

Fig. 2 is the positive sectional view of Fig. 1.

Fig. 3 is the III-III line sectional view of Fig. 2.

Fig. 4 is the major component cross section plan view of helical rotor.

Fig. 5 is the axle right-angle cross-section figure of helical rotor.

Fig. 6 is the enlarged view in the bight of helical rotor.

Fig. 7 is the explanatory drawing of relation of the formation length of expression transversal width of axial direction of Topland and Topland curve.

Fig. 8 is the diagrammatic illustration figure of the processing method of expression helical rotor of the present invention.

Fig. 9 is the diagrammatic illustration figure of the processing method of expression helical rotor of the present invention.

Figure 10 is the existing helical rotor of expression, (A) is the axial direction sectional view, (B) is the axle right angle orientation sectional view of interference state in expression bight, (C) is the axle right angle orientation sectional view of representing to be provided for to prevent the state of the otch of interfering.

Figure 11 is existing other helical rotor of expression, (A) is the axial direction sectional view, (B) is an enlarged view in the bight in orthogonal direction cross section.

Figure 12 is the explanatory drawing that is formed at the pore of existing helical rotor.

Among the figure: 13 ': the Topland curve; 14: the bight; 15: the bight; 17 ': tooth bottom surface curve; 18 ': the flank curve; 19 ': the flank curve; 24: the end; 25: the end.

Embodiment

Below, with reference to the description of drawings embodiments of the present invention.And, in mode of execution shown below, expression is used in the example of vacuum pump with helical rotor 10 of the present invention, but helical rotor 10 of the present invention can not only be as the helical rotor of vacuum pump 1 usefulness, and can be applicable to various screw fluid machines such as screw compressor or other volute pump.

(integral body of vacuum pump constitutes)

In Fig. 1, the 1st, possess a configuration example of the vacuum pump of helical rotor 10 of the present invention (10a, 10b), this vacuum pump 1 is housed in 2 above-mentioned helical rotors 10 (10a, 10b) in the shell 30 and can rotates.

Accommodate 2 cylinder barrels 31 that are helical rotor 10a, the 10b of engagement mutually in the formation of the inside of this shell 30, and be supported to and rotate by the rotor shaft 11 of bearing 32 with each

helical rotor

10a, 10b.

Among helical rotor 10a, the 10b, rotor shaft 11 at driving side rotor 10a directly connects motor or motor, reaches the output shaft 41 of other driving source (being motor 40 in the present embodiment), or connects this output shaft 41 by booster engine, other power transmission mechanism.

In the present embodiment, the output shaft 41 of motor 40 directly is connected with the rotor shaft 11 of this driving side rotor 10a, make driving side rotor 10a rotation along with the rotation of motor 40, and make the passive side rotor 10b rotation that is engaged in this by the rotation of this driving side rotor 10a.

The synchronous rotation of this driving side rotor 10a and passive side rotor 10b, the engagement of the timing gear 12 of the rotor shaft 11 by being arranged at each

helical rotor

10a, 10b is carried out, make two

helical rotor

10a, 10b with pettiness mesh at interval constituted.

At the outer wall of the shell 30 that is formed with described cylinder barrel 31, form the introducing port 42 that distolateral being used to that is positioned at

helical rotor

10a, 10b that is communicated to the space in the cylinder barrel 31 respectively imports fluid; And be positioned at the exhaust port 43 that fluid is discharged in another distolateral being used to, when the above-mentioned driving side helical rotor 10a of rotation, engagement by this timing gear 12 is rotated passive side helical rotor 10b round about, fluid imports by in the formed action space of the engagement of

helical rotor

10a, 10b by above-mentioned introducing port 42, the fluid that this imported between

helical rotor

10a, 10b in the formed action space when another distolateral conveying of

helical rotor

10a, 10b, volume shrinkage, after being compressed, discharge from above-mentioned exhaust port 43.

Accommodate the cylinder barrel 31 of helical rotor 10 (10a, 10b), be roughly 8 fonts of cross section as shown in Figure 3,2

helical rotor

10a, 10b can be accommodated with engagement, and the position, boundary line of inwall and the inwall that constitutes the chamber accommodate passive side rotor 10b of accommodating the chamber of driving side rotor 10a in formation is formed with crest line 33.

And, at Fig. 1～mode of execution shown in Figure 3, illustrate will have identical profile of tooth 2 helical rotors to be contained in the situation in the cylinder barrel under the opposite engagement of Hand of spiral, but the castellated shape of this helical rotor 10 (10a, 10b) also can be the different shape of each

helical rotor

10a, 10b, as long as the state in engagement can rotate, its shape is not limited to illustrated embodiment.

In addition, equally in illustrated embodiment, though illustrate the example that only forms 1 spiral at each

helical rotor

10a, 10b, each

helical rotor

10a, 10b also can form 2 or more than many rotors of 2 spirals, or make the bar of each

helical rotor

10a, 10b count difference.

(helical rotor)

Employed helical rotor 10 of the present invention in the vacuum pump 1 that constitutes as mentioned above, as shown in Figure 4, the helical screw serrated form forms with angle of lead α.

Helical rotor of the present invention, as shown in Figure 4, cross section at its axial direction, one side, the 18 relative line Y of

flank

18,19 form the curved shape that subsides to Fig. 4 left side slightly, line Y is formed at the direction with the axis X quadrature of helical rotor, therefore, be positioned at a bight 14 in Topland 13 and the

bight

14,15 of the link position of flank 18, cross section at the axial direction of helical rotor 10 acutangulates slightly, 17 is inclined to standing shape to peripheral direction with the continuous flank 18 in the bight 14 that forms this acute angle from the tooth bottom surface.

And another bight 15 becomes the obtuse angle slightly in the cross section of the axial direction of helical rotor 10, forms the plane of inclination that tilts to tooth bottom surface 17 with the continuous flank 19 in this bight 15.

Like this profile of tooth of the axle right-angle cross-section of the helical rotor 10 that forms, as shown in Figure 5, by following 3 curves its shape of roughly drawing: by the axle center O with helical rotor is radius centered r ₁The Topland curve 13 ' that circular arc constituted, be center and by axle center O with the radius r littler than the circular arc of Topland curve with helical rotor ₂The tooth bottom surface curve 17 ' that circular arc constituted and be formed at flank curve 18 ', 19 ' between these 2 curves.

Between the two ends of Topland curve 13 ' and flank curve 18 ', 19 ' in the formed above-mentioned

bight

14,15, acutangulate bight 14, shown in Fig. 6 solid line, the curve A-G that connects an end G of flank curve 18 ' by the end A from Topland curve 13 ' forms.

Form the curve A-G of the axle right-angle cross-section shape in this bight 14, form end A from the Topland curve 13 ' shape that 14 projected direction radius of curvature reduces gradually towards the bight, for example form by the quadratic curve that satisfies this condition, in present embodiment, be the sectional shape that forms bight 14 by the curve A-G that a part constituted of ellipse, this long axis of ellipse one end is the top F ' of this curve mean curvature radius minimum.

In addition, by the shape in the bight 14 that this curve A-G constituted, be not limited to above-mentioned ellipse, so long as from the curve of an end A of the Topland curve 13 ' shape that 14 projected direction radius of curvature reduces gradually towards the bight, Any shape all can.In above-mentioned example, be quadratic curve, particularly, it is an oval part, but the shape in this bight 14, so long as from the end A of the Topland curve 13 ' shape that 14 projected direction radius of curvature reduces gradually towards the bight, be formed centrally the shape of symmetry in then may not with top F ' being as quadratic curve.And, in the example of above-mentioned quadratic curve, except that ellipse, the curve that also can be obtained with parabola, hyperbola etc. or constitute for example with its part.

Constitute the curve in bight 14, unnecessary is correct oval or other quadratic curve, for example also can get a plurality of arbitrfary points on this quadratic curve, connect curve that forms continuous approximate quadratic curve etc. by the curve that connects sleekly between this point, its shape is not limited to the situation of mode of execution.

Because bight 14 is formed end A from the Topland curve 13 ' curve that 14 projected direction radius of curvature reduces gradually towards the bight, form by this quadratic curve especially, so when helical rotor 10 thermal expansions, bight 14 is difficult for the inwall of contact cylinder barrel 31, its result can make the gap delta t between Topland 13 and cylinder barrel 31 inwalls narrow as far as possible.

And the axle right-angle cross-section of comparing bight 14 is shaped as circular-arc existing helical rotor 10, and the present invention can make the pore of formation as far as possible little.

By above-mentioned bight 14 is formed the axle right-angle cross-section shape that reduces gradually towards the projected direction radius of curvature, just can make the narrow gaps between Topland 13 and cylinder barrel 31 inwalls, illustrate with reference to Fig. 5 and Fig. 6 with regard to this point, this kind helical rotor 10, make the problem of helical rotor thermal expansion when having considered running owing to the heat of compression of the fluid that is taken place, so the gap delta t (with reference to Fig. 6) of the thermal expansion amount of having considered the helical rotor that this thermal expansion produced 10 is set between the inwall of the Topland 13 of helical rotor 10 and cylinder barrel 31.

But, being arranged at the gap delta t between this Topland 13 and cylinder barrel 31 inwalls, this gap delta t obtains wide more, and the sealing between Topland 13 and cylinder barrel 31 inwalls is then low more, so preferably this gap delta t is narrow as far as possible.

When vacuum pump turned round, the fluid in the action space was heated by this fluid by the surface of the action space that helical rotor was drawn as owing to compression is generated heat, and makes the helical rotor thermal expansion.The position of thermal expansion amount maximum in helical rotor was towards action space and was positioned at bight 14 from the axis of rotation farthest this moment, but for the curve A-G that will constitute this bight 14 forms the shape that reduces gradually towards the projected direction radius of curvature, so form the shape of leaving cylinder barrel 31 inwalls from an end A forward end direction of Topland curve 13 ' gradually.So,, except that gap delta t, also have gap delta t ' thus in the bight 14 of the influence that is vulnerable to thermal expansion most.

Therefore, at this gap delta t ', if can compensate the increasing amount to the thermal expansion amount of peripheral direction in bight 14, gap delta t between Topland 13 and cylinder barrel 31 inwalls, then the amount of deformation of an end A of Topland curve 13 ' being used as maximum value gets final product, its result, the gap delta t between Topland 13 and cylinder barrel 31 inwalls can be narrow as far as possible.

To this, as introducing in prior art, when the axle right-angle cross-section shape with bight 14 makes circular arc, if want to guarantee the suitable outstanding length of outstanding length with the bight 14 of helical rotor 10 of the present invention, then as shown in phantom in Figure 6, the end of Topland curve 13 ' must further extend to the position A ' of the forward end in bight 14.And the gap delta t that should form between Topland 13 and cylinder barrel 31 inwalls then must consider to decide at the thermal expansion amount to peripheral direction of this A '.

But, the end A ' that is positioned at the projected direction forward end in bight 14 is positioned at the peripheral direction more than curve A-G, compare with above-mentioned some A, near action space and be vulnerable to the heat affecting of action space, so, must broaden by the gap delta t that benchmark is determined with the amount of deformation of this end A ' in the big part of thermal expansion amount.Therefore, the internal diameter of cylinder barrel 31 also becomes greatly, end A ' in addition Topland 13 and cylinder barrel 31 inwalls between the crack become big, be easy to generate the leakage of fluid by this gap.

On the other hand, same with helical rotor of the present invention 10, if some A among Fig. 6 is used as in the end of Topland curve 13 ', then at this A by forming bight 14 in succession and with flank curve 18 ' circular arc (dot and dash line among Fig. 6) in succession with Topland curve 13 ', it is very big that the otch in bight 14 then becomes, make 14,14 formed pores in bight of helical rotor 10a, the 10b of engagement become big, the result becomes unpractical helical rotor.

So, helical rotor 10 of the present invention, can make the gap delta t between Topland 13 and cylinder barrel 31 inwalls narrow as far as possible, can improve the sealing of this part thus, but in order to improve the sealing between Topland 13 and cylinder barrel 31 inwalls, the suitable practice is to substitute above-mentioned formation or with above-mentioned formation, makes Topland curve 13 ' be formed centrally 90 ° to 180 ° profile of tooth of whole relatively periphery (360 °) in the axis of rotation of helical rotor 10 being.

Suppose to be radius r with the most peripheral ₁The Topland 13 of helical rotor 10 formed profiles of tooth be deployed in state on the plane, 13 energy of this Topland assign to represent with the hypotenuse of the right-angled triangle △ with the hypotenuse that tilts with angle of lead α and the strap that is formed between the straight line parallel with this hypotenuse.

Herein, when being around in above-mentioned band-like portions on the cylinder, if be R by the helical pitch of the formed helix of hypotenuse of above-mentioned right-angled triangle, this helical pitch R then is expressed from the next.

R＝2πr ₁tanα

And,, then exist in the axle right-angle cross-section of rotor length from 90 ° to 180 ° the Topland curve 13 ' that scope occurred

2 π r ₁/ 4≤Topland length of a curve≤2 π r ₁/ 2

Scope, the transversal width R ' of the Topland 13 of the axial direction of helical rotor 10 then exists

πr ₁tanα/2≤R’≤πr ₁tanα

Scope, that is, the transversal width R ' of the axial direction of Topland 13 then is 1/4 to 1/2 the length of helical pitch R.

So, axle right-angle cross-section at rotor, owing to constitute the Topland curve of Topland 13 and be the profile of tooth of the shape that occurs 90 ° to 180 ° scope, so the width of Topland 13 can be guaranteed to be certain width at relative helical pitch length, the sealing between raising Topland 13 and inner wall of cylinder.

Promptly, Topland curve that the axle right-angle cross-section occurred 13 ' for the axis of rotation with helical rotor 10 be the center whole circumference (360 °) below 90 ° the time, the transversal width R ' of the rotor axis direction of Topland 13 then is the length below 1/4 of helical pitch R, the narrow width of Topland 13, can not give full play to the sealing between Topland 13 and inner wall of cylinder, but it is as above-mentioned with the scope formation of Topland curve 13 ' at 90 ° to 180 °, just can improve the sealing of this part, and the time with the combination of shapes in above-mentioned bight 14, can make the gap delta t between Topland 13 and cylinder barrel 31 inwalls narrow as far as possible, simultaneously, use the operating efficiency of the screw fluid machine of this helical rotor 10 significantly to improve.

In Fig. 6, the flank curve 18 ' of junction curve A-G and tooth bottom surface curve 17 ' (the curve G-H among Fig. 6), the profile of the flank 18 in expression axle right angle orientation cross section, this flank curve 18 ' is when two rotors rotate synchronously, formation is by the formed curve of curve A-G, and curve A-G constitutes the bight 14 of another helical rotor of the above-mentioned shape that meshes with this helical rotor.

By making flank curve 18 ' become the formed curve of curve A-G in the bight 14 of the helical rotor that constitutes rotation, when 18 of the flanks of the bight 14 of a side helical rotor and the opposing party's helical rotor seal action space, since arbitrary position of the curve A-G in the bight 14 that constitutes side's helical rotor, and arbitrary position of the flank curve 18 ' of the opposing party's rotor between action space sealed, so sealing is good.

(manufacture method)

Above helical rotor, as one for example Fig. 8 and shown in Figure 9 be that cutter by rotation comes cutting.In this cutting, the formation direction of teeth groove that axle center 4 correspondences of tool rotating shaft 3 have the helix angle of regulation is the angle of lead α of profile of tooth, and axis of rotation 7 tilt angle alpha of workpiece are installed on this tool rotating shaft 3 with single cutter with spacer element 2 relatively.

The cutter rotating center Oc of single cutter is provided with the spacer element 2 of length L at tool rotating shaft 3, the cutter rotating center Oc ' when installing so relatively spacer element 2 is not set, right-hand only off normal L in figure.Therefore, the elongation line of the movement direction of cutter rotating center is then set the position of departing from predetermined distance by to the below of the axis of rotation 7 of workpiece for.

Below, illustrate that the cutter that utilizes after the rotating center Oc off normal makes the method for helical rotor, at first, will be along the single cutter of tool rotating shaft 3 to right-hand off normal, to the direction of axis of rotation 7 quadratures of workpiece 6, to the workpiece 6 side shiftings distance corresponding with bite.Then, make the single cutter rotation by tool rotating shaft 3.This moment, workpiece 6 was on the axis of rotation 7 of workpiece spindle 9 and than the more processing initial position standby in left side of single cutter.

Then, making workpiece 6 is that move to the right in axis of rotation left side from figure, center edge rotation edge with its axis of rotation 7.

When workpiece arrives at the processing final position, make single cutter workpiece away from keyboard, make workpiece be back to the processing initial position to the left along workpiece spindle 9.

Next, make single cutter, make the single cutter rotation by tool rotating shaft then to the direction of axis of rotation 7 quadratures of workpiece 6, move the distance corresponding with bite to workpiece side.

Then, making workpiece 6 is that move to the right in its axis of rotation 7 left side from figure, center edge rotation edge with its axis of rotation 7.

When workpiece 6 arrives at the processing final position, make single cutter workpiece 6 away from keyboard, make workpiece 6 be back to the processing initial position to the left along workpiece spindle 9.

Carry out above action repeatedly to obtaining to process the teeth groove of screw serrated form till the desirable profile of tooth.

As mentioned above, use the cutter of rotating center Oc off normal, even if single cutter is moved to workpiece side in the mode of corresponding bite, on the elongation line of the movement direction of the rotating center of cutter, do not dispose the axis of rotation of workpiece, so can process the teeth groove of the helical rotor of

flank

18,19 inclinations, and the relative substantially horizontal of axis of rotation of cutter is tilted.But helical rotor 10 of the present invention is not limited to the processing of said method, and the known processing device that also can use the relative substantially horizontal of axis of rotation of cutter not tilt is made.

In addition, because the angle of lead α that helical rotor has regulation, if the part in above-mentioned Tool in Cutting bight 14 is formed the circular-arc of predetermined radius, the shape that then can be formed on the bight 14 of helical rotor 10 on the cross section of a right angle orientation easily is towards the bight elliptical shape that 14 projected direction radius of curvature reduces gradually.

And, make cutting corner part the cutting edge that is shaped as circular arc manufacturing or again the operation of sharpening be easier to, and be circular-arc cutting tool compared with acutangulate cutting tool, be difficult for producing breach or wearing and tearing and can life-saving, can the long period correctly carry out the cutting of rotor.In addition, owing to make the cutting edge that is shaped as circular arc of the part of cutting corner, its bight can not produce the burr that cutting causes, so must not carry out the operation of deburring, can not remove the sealing reduction that operation reams the bight and makes action space by Yin Maoci then.

According to formation of the present invention discussed above, the helical rotor that possesses profile of tooth of the present invention can obtain the potted line completely between helical rotor, and, can make pore as far as possible little.Its result can provide the helical rotor that improves sealing.

And, can make between Topland and inner wall of cylinder between the crack narrow as far as possible, simultaneously relatively 90 ° to 180 ° of the whole circumference of helical rotor form the Topland curve that occurs on the axle right-angle cross-section, so can improve the sealing between Topland and inner wall of cylinder.

In addition, form circular-arc by the region of interest that makes cutting tool, can form this shape that is used to improve the bight of sealing easy as can, and the situation that forms sharp keen shape with the region of interest of cutting tool is compared, life-span is longer, before cutting tool rust or machining accuracy can not be guaranteed and must the replacing instrument, also can process many helical rotors, reduce the number of times of tool changing operation.

Claims

1. helical rotor, this helical rotor are used to make a pair of helical rotor to mesh the screw machine that rotation sucked and discharged fluid in the opposite mode of Hand of spiral, and this helical rotor is included in the described a pair of helical rotor, wherein,

The profile of tooth of each of described a pair of helical rotor right-angle cross-section possesses: constitute the Topland curve of Topland profile, it is by being constituted with the axis of rotation of the helical rotor circular arc by the predetermined radius at center; Constitute the tooth bottom surface curve of tooth bottom profile, it is made of and radius concentric with the described Topland curve circular arc less than the radius of described Topland curve; And 2 flank curves of formation flank profile, it is formed between described Topland curve and the described tooth bottom surface curve,

Wherein, with a side in formed bight between the two ends of described Topland curve and described 2 the flank curves, the curve between an end by connecting described Topland curve and the end of described flank curve forms,

It is characterized in that:

With the curve that connects between the end of end of described Topland curve and flank curve, form the curve that reduces gradually from the projected direction radius of curvature of an end towards described bight of Topland curve, and the flank curve that makes this bight link tooth bottom surface curve becomes the curve that is generated by a side in the described bight of another helical rotor in the described a pair of helical rotor.

2. helical rotor, this helical rotor are used to make a pair of helical rotor to mesh the screw machine that rotation sucked and discharged fluid in the opposite mode of Hand of spiral, and this helical rotor is included in the described a pair of helical rotor, wherein,

The profile of tooth of each of described a pair of helical rotor right-angle cross-section possesses: constitute the Topland curve of Topland profile, it is by being constituted with the axis of rotation of the helical rotor circular arc by the predetermined radius at center; Constitute the tooth bottom surface curve of tooth bottom profile, it is made of and radius concentric with the Topland curve circular arc less than the radius of Topland curve; And 2 flank curves of the described flank profile of formation, it is formed between described Topland curve and the described tooth bottom surface curve,

Wherein, with a side in formed bight between the two ends of described Topland curve and 2 the described flank curves, the curve between an end by connecting described Topland curve and the end of described flank curve forms,

It is characterized in that:

With the described curve that connects between the end of end of described Topland curve and described flank curve, form the curve that reduces gradually from the projected direction radius of curvature of an end towards described bight of described Topland curve, and the flank curve that makes this bight link described tooth bottom surface curve becomes the curve that is generated by a side in the described bight of another helical rotor in the described a pair of helical rotor, and

At least one side in the described a pair of helical rotor is in 90 ° to 180 ° the scope at center with the axis of rotation that the Topland curvilinerar figure is formed in described helical rotor.

3. helical rotor as claimed in claim 1 or 2 is characterized in that: the described curve that forms between the end of a side end axle right-angle cross-section shape, that connect described Topland curve in described bight and described flank curve is made of the quadratic curve that the projected direction radius of curvature towards described bight reduces gradually.

4. helical rotor as claimed in claim 1 or 2 is characterized in that: a part that forms the ellipse that the described curve between the end of a side end axle right-angle cross-section shape, that connect described Topland curve in described bight and described flank curve reduces gradually by the projected direction radius of curvature towards described bight constitutes.

5. helical rotor as claimed in claim 1 or 2 is characterized in that: form described curve between a side the end of end axle right-angle cross-section shape, that connect described Topland curve and described flank curve in described bight and be the curve that is similar to this quadratic curve that a plurality of points on the quadratic curve that reduces gradually by the projected direction radius of curvature that is connected towards described bight form.