JPS60178989A - Screw rotor - Google Patents

Abstract

PURPOSE:To produce an easy-to-machine screw rotor profile where abrasion at the sealing point is avoidable by specifying the tooth profile of screw rotor comprised of male and female rotors rotatable while gearing around two parallel axes. CONSTITUTION:The back side tooth profile of a male rotor along the tip to the dedendum is formed with an arch of radius R1 having the center same with the center of rotation of male rotor making the central angle theta2 with a line connecting between the center of rotation of respective rotor, an arch of radius R4 touching internally with the arch of radius R1 while having the center on the radius line extending from the center of rotation of male rotor and an epicycloidal curve to be formed by the cross points of female rotor back side tooth profile and the pitch circle of said rotor. The center of arch of radius R4 is formed remotely from a line connecting between the center of rotation of respective rotor. While the back side tooth profile of female rotor is formed by an envelope to be formed with arches of radius R4 of rotor.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a screw machine for compressing or expanding a compressible fluid.
This relates to a q-shaped concave curve.

PRIOR ART In general, a screw rotor with an asymmetric tooth profile used in a compressor for compressible fluid, etc., has a male rotor with a main part of its tooth profile outside the pitch circle of the I-coater, and a male rotor with a main part of the tooth profile outside the pitch circle of the rotor. Usually, a male rotor with a plurality of teeth is meshed with a female rotor having a slightly larger number of teeth, The diameter of the tip of the tooth tip of the rotor coater and the diameter of the pinch circle of the female rotor are set to be approximately equal.

A pair of screw rotors of this type are placed in two cylindrical spaces whose centers are parallel to each other and whose diameter is equal to the outer diameter of each rotor, and where the distance between their axes is less than the sum of their radii. It is rotatably housed in a casing that is short and has a space whose axial length is the same as the axial length of the rotor, and both open ends of the casing are closed with end plates. By drilling the mouth and outlet,
A screw compressor or expander is configured. [See Figures 3(a) and 3(b)] When using the above device as a compressor, the female rotor should be rotated counterclockwise and the male rotor clockwise in the figure. However, in this case, when looking at the tooth profile curve of the female rotor, the front side in the rotation direction of the curve forming the tooth groove is called the forward side tooth profile, and the curve on the rear side in the rotation direction is called the following side tooth profile.
Regarding the curves forming the tooth profile of the male rotor, the front side in the rotation direction will be referred to as the forward tooth profile, and the curve on the rear side in the rotation direction will be referred to as the following tooth profile curve.

When the device is used as an expander, the respective curves function oppositely, but in the description herein:
All of these will be explained as being used as compressors.

1 (a) and 1 ib 1 of the screen and rotor described in 2 above are the tooth profile curves seen when the rotor is cut by a plane perpendicular to the rotor rotation axis, that is, the longitudinal end surface of each rotor. The tooth profile of the screw rotor in FIG.

? By rotating inside the casing (not shown) in the direction of the arrow, respectively, around the rotating downy hair (center of the pitch circle) 3.4, they function as a fluid compressor. 1
5 and 16 are pitch circles of the male rotor and female rotor 2, respectively, and the straight line connecting each rotation center 3.4 passes through the contact point 17 of the pitch circles 15 and 16, that is, the pitch point.

Note that the tooth profile curve described below will be described with reference to the screw rotor that functions as a compressor as described above. Refer to Figure 1(b). (1) Female rotor tooth profile (A) On the forward side line 3.4, point 12 at the deepest point in the center of the tooth profile of the female rotor, facing the tip 11 of the ascending tooth profile, 1. Centering on the contact point (pitch point) 17 of the pitch circle 15.16 of both rotors.
4 as a radius, and the outer part 11 of the curve
~] Between O is the pitch circle center of the female rotor (rotation center)
4, circular arcs 11 to 12 with a radius of 1-4 (formed by tangent lines that meet each other, and the curve between 12 and 13 at the bottom of the female rotor groove are circular arcs centered on the rotation center 4 of the female rotor and having a radius of r2, In addition, the outer diameter of the tip circle is made to match the pitch circle 16 of the female rotor.

(b) Let the curves 13 to 14 on the following side of the groove of the female rotor on the following side be an ebitrochoid curve created by point 8 on the male rotor.

(2) Male rotor tooth profile A) The curve between the center apex 7 of the male rotor tooth profile on the forward side and the point 6 at the tooth profile root is the pitch circle 15.1 of both the female and male rotors.
．． 6 contact point (pinch point) 17 as the center, and the radius r4
A circular arc having a radius r3, which is smaller by the amount of gap required for rotation, is defined as an envelope formed by a straight line between the tooth tips 10 and 11 of the female rotor between the point 6 and the dedendum 5.

(b) The curve between points 7 and -8 on the following side of the tooth profile of the male rotor on the following side,
A circular arc centered on the rotation center (pitch circle center) 3 of the male rotor and radius r1, and the curve from point 8 to dedendum point 9 is an evisaicroid created by the tip 14 of the opposing female rotor. By making it a curved line and matching the diameter of the bottom of the groove between 5 and 9 with the pitch circle 15 of the male rotor,
Point 8 is determined so that the contact line of both the female and male rotors on the ridgeline resting on the threads reaches the intersection line of the compression chamber shut-off side of the cylinder that accommodates both rotors. Further, the point 8 is formed far away from the straight line connecting the rotation centers 3.4 of each rotor.

Since the tooth profile of both rotors is defined as above, the short circuit leakage space (blow hole) between the compression chambers can be made virtually zero, and the tooth tip of the female rotor can be set to the pitch diameter. To eliminate interference between the tips of the female rotor's teeth at the root of the male rotor's teeth and improve the closing effect.

(bl) By moving the point 8 on the male rotor tooth profile far away from the straight line connecting the rotation centers 3.4 of both the female and male rotors, a space 18 is created at the contact area between the low-pressure side end plate and the male and female rotors. Since the rate of volumetric expansion accompanying rotation of the rotor is small, there is little power loss due to the vacuum generation effect based on volumetric expansion.

Although there are advantages such as, the following problems are also pointed out. That is, (C) the space volume is small (the stroke volume is small).

(di) Because the bottom of the female rotor tooth profile is uneven, the sole properties are not good and it is difficult to measure dimensions during processing.Furthermore, the outer shape of the cutter is complicated and processing is difficult.

(el Since the following curve of the female rotor tooth profile is a point generation,
The sealing point is easily worn and the sealing effect is difficult to maintain.

Since the pressure angle becomes almost 0 near the pitch circle, it is difficult to perform accurate machining and the tool life is shortened.

Especially when hobbing screw rotors, the life of the hobbing tool is shortened.

Figure 1(a) shows the phase of the tooth profiles of both rotors immediately after point 8 of the male rotor tooth profile of the rotor having the above-mentioned tooth profile and the 13 to 1.4 curve of the female rotor tooth profile start contacting. , and then the male rotor rotates about 20 times, causing the first
(b) The phase shown in the figure is reached, but the contact surface indicated by the reference numeral 18 in Fig. 1(a) is 18 in Fig. 1(b).
Since it expands into a space such as , a vacuum space is created in this part and the necessary power (unrelated to compression) is consumed, so it is preferable that the space volume does not become large. The above-mentioned tooth profile has a small rate of volumetric expansion, so the power loss is small.

For example, one of the conventional tooth profiles used by other companies, Tokuko Sho 56-1
The tooth profile of the rotor used in the screw rotor machine described in Publication No. 7559 is as shown in Figure 2, and in the figure, the configurations with the same symbols as in Figure 1 are the same parts 4, in Figure 2. (1) Female rotor tooth profile (a) Advance side 28-29; An arc with a radius of 1゛'1 centered at point 36 on the straight line 1.7-29.

29-30: Circular arc with radius r'2 centered on pinch point 17.

(b) Follow-up side 30-3]; Ebitoroid curve defined by point 23 on the male rotor tooth profile.

31-32; A straight line passing through the rotation center 4 of the female rotor.

32-33; Arc having its center on the pitch circle 16.

33-34; Arc centered on rotation center 4.

34-35; Arc having its center on the pitch circle 16.

(2) Male rotor tooth profile a) Forward side 21-22; Female rotor tooth profile 28-29 (straight line 17-
29 (circular arc with radius r'1 centered at point 36) (/C
Envelope, according to.

22-23: Circular arc with radius r'2 centered at Pinauve point 7.

-) Follower side 23-271; epitrochoidal curve with point 31 on the female rotor tooth profile.

24-25; Straight line 3], -32 generated curve.

25-26; Arc having its center on the pitch circle 15.

26-27; Arc centered on rotation center 3.

27-28; Pitch circle 15 An arc centered on the soil. - However, the capacity of the illustrated space (vacuum creation space) 18 is larger than that of the tooth profile illustrated in the first figure.

OBJECTIVE: The present invention solves the problems without losing the advantages of the tooth profile shown in the first drawing conventionally used by the applicant, or by reducing the losses as much as possible. To provide a new tooth profile that prevents the problems mentioned above, especially at the /-ru points, eliminates the reduction in efficiency over long-term use, and solves the problems in forming processing. The purpose is to The detailed configuration and effects thereof will be made clear in the description of the embodiments described below.

Structure The present invention provides a screw row 2 consisting of a female rotor and a male rotor that rotate in mesh with each other around two parallel axes, and each tooth profile of the female rotor has a main portion within the pitch circle of the same rotor. Formed and removed. - Each tooth profile is of the type in which the main part is formed inside and outside the pinch of the same rotor, and within a plane perpendicular to the rotational axis of each rotor ((in each tooth profile curve formed, at least The side tooth profile is defined as an arc with a radius R1 centered at the male rotor's rotation center and sandwiching a center angle θ2 when looking at one side from the straight line connecting the rotation centers of each rotor from the tooth tip to the root side. , the intersection of a circular arc with a radius R4 inscribed in the circular arc with a radius R+ drawn with the center on a radial line extending from the rotation center of the male rotor, the follow-up side tooth profile curve of the female rotor, and the pitch circle of the same rotor. The circular arc center position of the radius R4 is formed to be similar to the ebicycloid curve created by the rotor, and the center position of the circular arc with the radius R4 is far away from the straight line connecting the rotation centers of each rotor. A screw rotor comprising an envelope formed by a circular arc having a radius R4 that extends from the tip to the tooth tip side and forms a part of the following side tooth profile of the male rotor.

2. A screw rotor consisting of a female rotor and an oscillating rotor that rotate in mesh around two parallel axes.Each tooth profile of the female rotor has its main part formed within the pitch circle of the same rotor, and the male rotor Each tooth profile of the rotor is of a type in which the main part is formed outside the bisotient circle of the same rotor, and in each tooth profile curve formed in a plane orthogonal to the rotation axis of each rotor, the tooth profile of the female rotor is The advancing side tooth profile has its apex at a position outside the pitch circle of the female rotor on a straight line connecting the rotation center of each rotor from the tooth tip to the bottom side VCG, and the angle of θ1 when looking at the straight line to one side. The tooth profile on the following side consists of a circular arc with a radius R2 circumscribed to a circular arc with a radius R3 drawn with the apex as the center, and a circular arc with the radius R3, and the tooth profile on the following side may be the tooth bottom. Returning to the tooth tip side, at least a circular arc with the radius R3 and a radius R4 forming a part of the following side tooth profile of the male rotor.
The forward tooth profile of the male rotor is formed by a curve that connects the envelope formed by the arc of radius R4, and the envelope formed by the arc of radius R4. As a result, an envelope formed by a circular arc of radius R2 of the advancing side tooth profile of the female rotor and an envelope formed by a circular arc of radius R3 are formed, and the following tooth profile is formed from the tip of the tooth. Looking at the straight line connecting the rotation centers of each rotor from the tooth base side, we can find an arc of radius Rx centered on the rotation center of the male rotor and a radius from the male rotor rotation center, sandwiching the center angle θ2. It is created by the intersection of a circular arc with radius R4 inscribed in the circular arc with radius R+, which is drawn with the center on the radius line extending to the other end of the circular arc of R1, and the following side tooth profile of the female rotor and the same pitch circle. The center position of a circular arc with a radius R4 that forms an ebicycloid curve and forms a part of the following side tooth profile of the male rotor,
A screw rotor characterized by being formed far away from a straight line connecting the rotation centers of each rotor.

One embodiment of the present invention will now be described with reference to the accompanying drawings.

FIG. 3 shows a compressor for compressible fluid constructed by incorporating the screw rotor of the present invention, and FIG. 3(a) and FIG. 3(b)
), the cross-sectional view taken along line A-A in figure 3),
(a1) is a vertical cross-sectional view taken along the line B-B shown in the figure. In cooperation with the support shaft 61 extending symmetrically to the shaft 6o, the rotor ↓ is moved to the bearing portion 64 of each end plate 62 and 63.
and 65, which are rotatably supported.

? is a female rotor that meshes with the male rotor, and is the rotor mentioned above? The end plate 62 also has a rotating shaft extending to each end face thereof.
．． 63 and is rotatably supported.

66 is a set of intermeshed rotors 1 and ? A low-pressure side end plate 62 that surrounds the outer periphery of the casing and has a suction port 67 on its longitudinal end face, and a discharge port 68.
A working space 69 is formed and partitioned by the connecting sheath 7, the rotor tooth groove surface, the casing inner wall, and the inner sides of both end plates. The working space 69 has a suction port 67 and a discharge port 68, respectively, communicating with a low pressure passage 70 and a high pressure passage 7 for working fluid in the casing. The cross section of the casing 66 is parallel to the cylindrical space.
When the two cylindrical spaces are lined up side by side, the distance between their center axes is half as small as that of each cylindrical space, so both cylindrical spaces have an overlapping part, and a ridge line 72 appears at the part where the inner walls of the rain space intersect.

Female rotor? is equipped with six grooves in which each spiral groove extends in the direction of the rotational axis (longitudinal), the shaft is usually twisted by 200 degrees, and the grooves are located inside the pitch circle of the rotor Z, The height of the teeth separating the grooves is limited to the pinch circumference, and the groove shape is a concave curve within the groove.

The male rotor 1 usually has four helical teeth, each of which runs along the rotation axis (longitudinal) direction, and has approximately 30 teeth around the rotation axis.
A torsion of 0° is given. The tooth height of the filaments is located outside the pitch circle of the rotor, and is the rotor fitted between the filaments? A groove is provided for the tooth to fit into, and the cross section of the tooth profile is similar to that of a long sword, with a convex curve on the outside.

The working space 69 is divided into a figure 7 shape, and after the rotation of the rotor closes the communication between the suction port 67 of the low-pressure side end plate 62 and the work J1-1 space, the meshing line of both rokes moves ( Due to the relative rotation of both rotors, the volume of the divided working space is reduced compared to that at the deadline of 9 o'clock, and during this time the compressible volume of the working space is adiabatically compressed and becomes high pressure and high temperature. The sexual fluid eventually communicates with a discharge port 68 formed in the high-pressure side end plate 63 and is discharged to the high-pressure chamber 71 side.

During this period, the rotor teeth, the engagement between the groove surfaces, the sliding surfaces between the casing inner wall and the sliding surfaces between the rotor end surface and the inner surfaces of both end plates are lubricated and airtightly maintained (sealed), and compressible. In order to cool down the heat generated by the adiabatic compression of the fluid, cooling oil is injected into the working space through the nozzle 73.

The screw rotor of the present invention relates to the tooth profile curves of both rotors used in the above-mentioned compressor.

Figure 4(a), ■) shows the tooth profile curve of each rotor seen when the screw rotor is cut in a plane perpendicular to each rotation axis. 15 is the pitch circle of the same rotor, male row 21
rotates around the rotation center 30 in the direction of the arrow.

? is a female rotor that meshes with the male rotor ↓, and rotates around the rotation center 4 in the direction of the arrow.

16 is the pitch circle of the female rotor, and the center of rotation is 3.4
It touches the pitch circle 15 on the straight line connecting the lines. pitch circle 15,
], 6 is the pitch point 17. Both pitches 15.1
The radius ratio of 6 is 2/3. Note that 18 is a space close to a vacuum generated at the contact portion.

Referring to Figure 4(b), (1) Tooth profile curve of female rotor (a) Forward tooth profile, from the tooth tip to the tooth bottom side, (a)
Between 47 and 4.8, there is an angle θ1-40 with the center point 52 of a circular arc of radius R3, which is on the straight line connecting rotation center 3 and 4 and is outside the pitch circle 16, as the apex and with the straight line. °~5
An arc with a radius R2 circumscribing an arc with a radius R3 drawn centering on a point 53 on a straight line that intersects 5 degrees.

+b) Between 48 and 49; Radius R centered on the point 52
3. Downy hair/angle θ, arc from -40° to 55°.

Approximately 3 dimensions, 1.05≦薊: 1≦13, however, PCR; male rotor pitch circle radius 3 π, -p. , is larger than 1, and θ
The smaller 1 is, the larger the pressure angle near the pitch circle of the tooth profile curve composing 48-49 can be, making it easier to form the tooth profile with a bob, and the closer 3 R,-PCB is to 1, the closer Furthermore, the larger θ1 is, the thicker the tooth profile of the female rotor can be.

In this example, θ1 and R3 were determined as υ above so that the pressure angle could be made sufficiently large and a tooth thickness sufficient in terms of strength could be ensured.

(c149) Following tooth profile, along the tooth bottom to the tooth tip side
-51: When an arc of radius R+ (344) centered on the rotation center 3 of the male rotor 1 extends a center angle θ2=4° to 8, the center is a point 54 on the radius line 3-44. An envelope formed by arcs 44-45 on the tooth profile curve drawn with radius R4.

Between 51 and 47 is the circumference of pitch circle 16.

Note that the arc 48-49 and the envelope 49-51 are connected to the straight line or arc 48-4 that is in contact with the respective arc and envelope.
Point 50 on curve 9 and point 500 on envelope 49-51 may be clearly connected by curve 50-50.

(2) Male rotor tooth profile a) Forward side tooth profile, along the tooth root to tooth tip side, (d) 41
−． 42: Female rotor? Arc 47 on the side tooth profile curve
-Envelope by 48.

(e) Between 42 and 43; female rotor? Envelope by arc 48-49 on the side tooth profile curve.

(b) Follow-up side tooth profile, curved from the tooth tip to the tooth root side) 43
-44 is a central angle θ2-4 to 80 arc centered around the rotation center 3 and defined by radius R1.

The larger θ2 is, the smaller the space 18 can be.
The smaller 2 is, the smaller the gap between the male and female rotors between 43-44 and 50-50 can be. In this embodiment, the space 18 can be made sufficiently small, and the gap between the male rotor and the female rotor between 44-44 and 50-50 can be set to such an extent that it does not pose a practical problem, and θ2 is as described above. A numerical value was established.

ig) Between 44 and 45 is an arc of radius R4 centered on point 54, which is centered on one radius 3-44. In relation to the value of θ2 in the above equation, the center point 54 of the circular arc with radius R4 is set far away from the straight line 3-4.

th) Between 45 and 46; is it a female rotor? tooth profile line 49-
-51 and the pitch circle 16 intersect 51.

(Between i146-41; Ozuguchi-Yu pitch circle 150
Circumference,.

Effect Since the tooth profile curve of the screw rotor of the present invention is as follows, in the regulations of +IHf) and fgl, (a) Radius line 3-44 extended from rotation center 3 of ↓
By providing J:, as shown in FIG. 8, the tangent to the arc 44-45 at point 44 and the line 3-4 passing through said point are 1111'i! Angle θ with t
5 can be made smaller than θ5 when it is provided on the radius line +7-44 extending from the center point 17, and the following tooth profile curve from Ozuguchi to Yu is the straight line 3- connecting each rotation center. 4
The tooth profile curve on the following side of the female rotor is moved further apart, and the vacuum creation space 18 can be made smaller.

(b) In the same figure, θ2 is increased and the center 54 of the circular arc with radius R4 is directly 1%! By forming the space 18 far away from 3-4, the space 18 can be further made smaller. That is, since the rate of volumetric expansion of the space 18 is relatively small while Ta rotates from the phase shown in FIG. 4(a) to the phase shown in FIG. 4(b), the power loss due to the vacuum creation is Less is,.

According to the condition of
In the same figure, the 4th point is sandwiched between semi-j degrees, which hardly causes any problems.
(b) Identical to the figure, the part with the sign is the same as that of the same figure, and has the same credit], and the first situation is omitted because it is effective. 7
Reference numeral 2 denotes the ridge line where the circumferential walls of the two circles 1' and 'X) provided in the casing 66 intersect, and is also the meshing point of the teeth of both rokes.

(3) - (Based on the cl line f1, as shown in Fig. 5, (a) The envelope curve of the circular arc 44-45 with radius R4 of the tooth profile curve of the male rotor ↓, is the envelope curve of the circular arc 44-45 of the male rotor↓? By setting the tooth profile curve 49-51, the wear resistance is improved compared to a male rotor tooth profile where the same location is an inflection point.

(B) When lubricating oil E is supplied between the contact surfaces with both curves 44-45. A wedge effect can be created to improve the lubrication and/or lubricating properties of the surface.

(4) From the conditions of fg+ mentioned above, a) Conventionally, important points as /- points [point 8 on the tooth profile curve in Figure 1(b), points 2:3 on the tooth profile curve in Figure 2] However, since it was a discontinuous point, it was difficult to accurately measure the position, and it was difficult to process with high precision. Since it is connected to both sides, it is easy to measure the position and it is possible to process with high precision.

(0) By eliminating discontinuous points on the tooth profile curve, the cutter can be manufactured easily, and the service life of the tool can be extended.

Based on the condition of +51(b), as seen in Figure 6,
(a) Compared to the case where the position of the point 52 is on the pitch point 17, that is, on the pitch circle 16, the space volume can be increased by the volume indicated by diagonal lines in the figure.

(b) The angle θ3 between the tangent to the tooth profile curve at point 48 and the straight line connecting the rotation center 4 and point 48 of the female rotor is,
Since it can be made larger than θ3 at an approximate point on the arc of radius 17'-49 drawn with the pitch point 17 as the center, the pressure angle near the pitch circle of the tooth profile curve composing the curve 48-49 is Since it is larger, it is possible to improve the machining accuracy of the tooth forming shape and extend the tool life.

(6) According to the condition +a+ above, compared to the case where the center point 53 of the arc 47-48 is 4'l on the same side as the center point 52 of the arc 48-49, The space volume can be increased by that amount.

(b) Since the angle θ4 between the straight line tangent to the curve at point 47 on the arc 47-48 and the straight line connecting the rotation center 4 of the female rotor and the point 47 can be made thicker, the pitch of the arc can be increased. The pressure angle near the circle can be increased, which is effective in improving machining accuracy and tool life.

(7) From the conditions of (d) and (el above), (bl and (
In conjunction with the condition c), the abrasion resistance can be improved by forming an envelope with arcs 47-48 and 48-49.

(b) When lubricating oil is interposed between the rain shelter surfaces, the lubricating oil creates a wedge effect due to the sliding of the contact surfaces, thereby improving the lubrication effect and sealing performance on the same surfaces.

As detailed above, according to the first invention of the present application,
A radius R centered on the rotation center of the male rotor, which is centered on the male rotor's rotation center, looking at the following side tooth profile of the male rotor from the tooth tip to the tooth root side, and looking at the straight line connecting the rotation centers of each rotor on one side, and sandwiching the corner of the center angle θ2.
1, a circular arc with a radius R4 whose center is on a radial line extending from the rotation center of the male rotor to the other end of the circular arc, and which is inscribed in the circular arc with the radius R1, and a follow-up side tooth profile of the female rotor. and an evisaicroid curve created by the intersection of the pitch circle of the same rotor, and the radius R4
The circular arc center position of the above-mentioned male rotor is formed far away from the straight line connecting the rotation centers of each rotor, and the trailing side tooth profile of the female rotor is cleaned from the tooth bottom to the tooth tip side. Since it is formed by an envelope formed by an arc of radius R4 that forms the part, the space (vacuum creation space) created at the contact part between the suction side end plate and the male and female rotors when both rotors mesh and rotate is reduced. In addition to reducing power loss due to vacuum creation, short-circuit leakage space (
blowholes) can be virtually eliminated. Also,
In the tooth profile on the following side of the screw rotor, the lubricating oil applied to the contact surface of the tooth profile curve can produce a wedge effect by sliding on the contact surface, improving lubricity and sealing performance. The durability can also be improved.

Still, according to the second invention of the present application, in addition to the above configuration, an arc of radius R3 is formed along the forward tooth profile of the female rotor from the tooth tip to the tooth bottom side, sandwiching a straight line connecting the rotation centers of each rotor. is formed by a circular arc having a radius R2 and a circular arc having a radius R3, which has a center opposite to the center of the rotor, and is in contact with the circular arc having a radius R3. hand,
Said female. Since the envelope is formed by the arc of radius R2 and the radius R3 of the advancing side tooth profile of -p, a space is created at the contact part of the tooth profile curve during meshing rotation between the suction side end plate and the male and female rotors. (vacuum creation space) can be made smaller and power loss due to vacuum creation can be reduced.

In addition, short-circuit leakage spaces (blowholes) can be virtually eliminated, and the wedge effect of the lubricating oil supplied to the sliding surfaces provides lubrication to the sliding surfaces in the following tooth profile and advancing tooth profile of the screw rotor. By increasing the pressure angle near the pitch circle and increasing the space volume,
By forming a tooth profile with excellent workability, hobbing becomes easier and the life of the tool can be extended.

As described above, according to the present invention, a practically useful screw rotor can be provided.

[Brief explanation of drawings]

1 and 2 are tooth profile curves of conventionally used screw rotors, and FIGS. 1(a) and 1(b) show a set of rotor tooth profile curves used by the present applicant. When the alignment phase is different, Figure 2 shows an example of the tooth profile used by another company.
3(a) and 3(b) are a side sectional view and a cross sectional view of a rotor machine implementing the screw rotor of the present invention,
FIG. 4(a) and FIG. 4(b) show the screw of the present invention.
The tooth profile curves of a pair of rotors are shown, and when the meshing phases are different from each other, FIGS.
The figure is a diagram explaining the presence or absence of blowholes in the screw rotor of the present invention. J...male rotor? ...Female rotor, 3 and 4,
...Rotor rotation center, 15 and X6...pitch circle, 1
8. Vacuum creation space. Figure 3 Cσ/i LA Figure 9 Procedure Amendment 1 March 1980 150 Commissioner of the Japan Patent Office Kazuo Wakasugi 1 Display of the case 1982 Patent Application No. 29588 2 Name of foaming Screw rotor 3 Amendment Relationship with the case involving the person who filed the patent application 4 agents for the patent applicant 107 Address: 3 Calm Building, 8-1-7 Akasaka, Minato-ku, Tokyo
B6 Number of inventions increased by amendment None 7 Clarity of the original application of the first application targeted by the amendment (“Scope of Claims” of If lj)
The column [Invention] "Claims" will be amended as follows. 1 A screw rotor consisting of a female rotor and a male rotor that rotate while meshing around the circumferences of two parallel axes, in which each tooth profile of the female rotor has its main part formed within the pitch circle of the same rotor, and the male rotor Each tooth profile is of the type in which the main part is formed outside the pitch circle of the same rotor, and in each tooth profile curve formed in a plane orthogonal to the axis of rotation of the abutment and the end, at least one part of the rotor is The follow-up side tooth profile is an arc of radius R1 centered at the rotation center of the male rotor, extending from the tooth tip to the root side and sandwiching the center angle θ2 when looking at one side with a straight line connecting the rotation centers of each rotor. and an arc of radius R4 inscribed in the arc of radius R1 drawn with its center on a radial line extending from the rotation center of the male rotor;
It is different from the ebicycloid curve created by the intersection of the following side tooth profile curve of the female rotor and the pitch circle of the same rotor, and the arc center position of the radius R4 is far away from the straight line connecting the rotation centers of each rotor. The following tooth profile of the female rotor is formed by an envelope formed by an arc of radius R1 that forms a part of the following tooth profile of the male rotor from the tooth bottom to the tooth tip side. of! Characteristic screw rotor. 2. A screw rotor consisting of a female rotor and a male rotor that rotate in mesh around two parallel axes, with each tooth profile of the female rotor having its main portion formed within the pitch circle of the same rotor, and Each tooth profile of the rotor is of a type in which the main part is formed outside the pitch circle of the same rotor, and among the tooth profile curves formed in the plane orthogonal to the rotation axis of each rotor, the tooth profile on the forward side of the female rotor is a straight line that connects the rotation center of each rotor along the tooth tip to the tooth bottom side, and the pitch circle of the female rotor also has its apex at the outer position, and when looking at the straight line on one side, the angle θ1 is The tooth profile on the following side consists of a circular arc with a radius R2 circumscribing a circular arc with a radius R3 drawn with the apex as the center, and a circular arc with the radius R3, which has a center on an extension line of the sandwiching straight line, and the tooth profile on the following side starts from the bottom of the tooth. Beach on the tooth tip side,
It is formed by an envelope formed by an arc of radius R4 that forms at least a part of the following side tooth profile of the male rotor, while the forward side tooth profile of the male rotor is formed from the tooth root to the tip side ICG. It is formed by an envelope formed by an arc of radius R2 of the advancing side tooth profile of the female rotor and an envelope formed by an arc of radius R3, and the following chevron is formed from the tooth tip to the root side. Looking at the straight line connecting the top and bottom of each mouth to evening rotation on one side, the arc of radius 1 centered on the center of rotation of the second rotor, sandwiching the center angle 02, and the radius from the center of rotation of the male rotor. On the radius line extending to the other end of the arc of R1 (the radius R drawn by 14 degrees from the center of C)
1 and the intersection of the following tooth profile of the female rotor and the same pinch circle, and forms a part of the following tooth profile of the male rotor. A screw rotor characterized in that the center position of a circular arc having a radius R4 is formed far away from a straight line connecting the rotation centers of each rotor. 2. In the "Detailed Description of the Invention" column, (a) page 12 of the specification, line 10, r 27-284, has been changed to [27-21], and (b) page 17, line 1 of the same specification has been changed to "not done." ” to “is being done.” ←→ Same No. 22, p.
-44'', 23rd page, /1st line ``tooth profile line'' to ``tooth profile curve'', (e) 25th page 2nd line ``49-51'' to ``49-
51'', (to) page 27, line 4 [conditions for (b) and 0'(c)'' to ``conditions for (a): t, b)'', (g) same page Page 29, lines 1-4 “With the center on the outside, -
``Tangential to a circular arc'' has been changed to ``The outer position is the apex, the center is on the extension of the straight line that sandwiches the angle θ1 when looking at the straight line on one side, and it is circumscribed by an arc of radius R3 drawn with the apex as the center.'' , respectively. 3. Amend Figure 2 of the accompanying drawing as shown in the attached sheet. (Indication line 24 has been added.) Figure 2 Procedural amendment April 8, 1985 Manabu Shiga, Commissioner of the Patent Office 1 Indication of the case 1982 Patent Application No. 29588 2 Name of the invention Screw Statement 3 Relationship with the case of the person making the amendment Patent applicant 4 agent 107 Address Calm Building 3, 8-4-7 Akasaka, Minato-ku, Tokyo
B8. Contents of amendment Attached specification] 1 Invention 1 Name of the invention Screw rotor 2 Claim 1 A screw rotor consisting of a female rotor and a male rotor that rotate while meshing two parallel shaft plates. Therefore, each tooth profile of a female rotor has a main part formed within the pitch circle of the same rotor, and each tooth profile of a male rotor has a main part formed outside the pitch circle of the same rotor. Among the tooth profile curves formed in a plane perpendicular to the rotor's rotation axis, at least the trailing side tooth profile of the rotor has a straight line connecting the rotation center of each rotor, running from the tooth tip to the tooth root side. An arc of radius R+ centered at the rotation center of the male rotor, sandwiching the center angle θ2 when viewed from one side, and the radius R1 drawn with the center on the radial line connecting the end of the arc and the rotation center of the male rotor. An epicycloid curve is created by the intersection of a circular arc with a radius R4 inscribed in the circular arc of the female rotor and the following side tooth profile curve of the female rotor and the pitch circle of the same rotor, and the center position of the circular arc with the radius R4 is The trailing side tooth profile of the female rotor extends from the tooth bottom to the tooth tip side and forms a part of the following side tooth profile of the male rope. A screw characterized by an envelope curve formed by a circular arc.
Rotor. 2 A screw rotor consisting of a female rotor and a male rotor that rotate in mesh around two parallel axes, each tooth profile of the female rotor having its main portion formed within the pitch circle of the same rotor, and Each tooth profile of the rotor is of the type in which the main part is formed outside the pitch circle of the rotor, and within a plane perpendicular to the rotational axis of each rotor (in each tooth profile curve formed, the advancement of the female rotor The side tooth profile has its apex at a position outside the pitch circle of the female rotor on a straight line connecting the rotation center of each rotor along the tooth tip to the tooth bottom side, and when looking at the straight line on one side, θ1. It consists of an arc with a radius R2 that has its center on an extension of a straight line that pinches the corner and circumscribes an arc with a radius R3 drawn with the apex as the center, and 1) an arc with a radius R3 in item 11, and the tooth profile on the following side is , the advancing side tooth profile of the mineral layer male rotor is formed by the circular arc with radius R4 that extends from the bottom of the teeth to the tooth tip side and forms a part of the following side tooth profile of the male rotor, including the stopper. From the tooth base to the tooth tip side (C bath,
Female - It is formed by an envelope formed by a circular arc V of radius R2 of a part of the advancing side tooth profile and an envelope formed by the circular arc of the front side medium diameter R3, and the following side tooth profile is Looking at the straight line that connects the rotation centers of each rotor on one side, looking at the straight line connecting the rotation centers of each rotor, an arc of radius R1 with the entire center of rotation of the male rotor as the center, and a radius from the male - partial rotation center, sandwiching the center angle θ2. It is created by the intersection of an arc of radius R4 inscribed in the arc of radius R] drawn with its center on the radius line extending to the other end of the arc of R1, and the following tooth profile of the female rotor and the same pitch circle. (1) The center position of the circular arc with radius R4, which forms an epicycloid curve and forms a part of the following side tooth profile of the male rotor, is set far away from the straight line connecting the rotating nozzles L of each rotor. ~
A screw I cork characterized by the following. 3. Details of the invention! 11 DESCRIPTION TECHNICAL FIELD The present invention relates to a pair of rotors used in screw machines for compressing or expanding compressible fluids, and in particular to their tooth profiles. BACKGROUND ART In general, screw rotors with asymmetric tooth profiles used in compressors for compressible fluids, etc., have two male rotors with the main part of the tooth profile outside the pitch circle of the rotor, and a male rotor with the main part of the tooth profile outside the pitch circle of the rotor. Usually, a male rotor with multiple teeth is meshed with a female rotor with slightly more teeth than the male rotor, and the diameter of the teeth of the male rotor is The pitch circle diameter of the stopper rotor is set to be approximately equal. The axis of the pair of screw rotors is -1
-L (1), the diameter of -t is equal to the diameter of each rotor (7), and the distance between their axes is equal to the radius of phase LL. In the ring (li, the two-turning position Q is included, and the space is the same as the axial length of the center axis, and the seven double openings [1
A screw compressor or expander is constructed by closing the ends with end plates and drilling suction ports [1] and discharge ports at the required locations. I'm here. [3rd (
a) and 3(b).'' When the above-mentioned device is used as a compressor, the female rotor is rotated counterclockwise and the male rotor is rotated clockwise in the figure. In this case, the tooth profile curve of a female rotor (if you look at it, the front side in the rotational direction of the curve forming the tooth groove is called the forward side tooth profile, and the curve on the rear side in the rotational direction is called the following side tooth profile,
The curve forming the tooth profile of the male rotor (10) will be referred to as the full advancing tooth profile on the front side in the rotational direction, and the curve on the rear side in the rotational direction will be referred to as the following tooth profile curve. When the device is used as an expansion device, the curves of each curve function in the opposite manner, but in the description of the present invention, all explanations will be made assuming that the device is used as a compression device. Nouri, Figure 1(a) and Figure 1
+1) Figure J shows the curve that can be seen when the rotor is cut by a plane perpendicular to the rotor's rotational axis, that is, the longitudinal force of the rotor.
This figure shows a tooth profile curve of a rotor, and the tooth profile is a tooth profile curve (see Japanese Utility Model Publication No. 1982-25552) that has been conventionally used by the present applicant, and its characteristics are as follows. That is, in the figure, J is the outer rotor, ? is the female rotor that meshes with the male rotor L, and these rotors y and ? are the center of rotation (center of the pitch circle) 3.4 By rotating in the direction of the arrow in the casing (not shown) around the center, it functions as a fluid compressor.] 5 and 16 are pitch circles of the male rotor l and female rotor l, respectively, and During each rotation, the straight line connecting L 3.4 (is the pitch circle) passes through the contact point I7 of 5 and 10, that is, the pitch point. Top - °C, female rotor Tooth profile, toe ffdii T 3-i facing from the deepest point 1'2 of the tooth profile center, both female and male rotors (,7) pitch circle 15, ], 6 contact point (pitch Point) 17wo center and 1no CI'4'%:
A circular arc with a diameter of 10, and the curved knee) seat force part 1
The curve between 1 and 100 is the pitch circle of the female rotor (center of rotation) 4 and the tangent to the arc 11 and 12 of radius r 4, and the curve between 12 and 13 at the bottom of the groove of the female rotor. ,%!
Let be the rotational arc of the female rotor with center 4 as the center and radius r2, and the outer diameter of the tooth tip circle as t'
○ Match pitch circle 10. (L)) Follow-up 11-1j Let the curves 13 to 14 on the follow-up side of the groove C of the female rotor be the L vitrochoid curve created by the point 8 of the male rotor. (2) Male rotor tooth profile (I) ) The curve between the center apex 7 of the male rotor tooth profile on the forward side and the point 6 on the root side of the tooth profile is the pitch circle 15 of both the female and rear rotors.
A circular arc centered on the contact point 17 of 16 and having a radius r3i smaller than the radius r4 by the gap required for rotation, and the point 6
From 10 to 5VrC at the tooth tip of the female rotor.
Let it be an envelope formed by a straight line between 11 and 11. (O) Let the curve between points 7 and 8 on the following side of the tooth profile of the male rotor on the following side be an arc with a radius of 1.1 and a radius of 1.7 with the rotation center of the male rotor as the center of rotation 7, and from point 8 to the root point. 9 (The curve up to IC is an evisicroid curve created by the tooth tip 14 (・) of the opposing female rotor, and the groove bottom diameter between 5 and 9 corresponds to the pitch circle 15 of the male rotor. (From <, point 8 is set so that the contact line of both the female and male rotors on the ridgeline of the threaded ridge line reaches the compression chamber closure side intersection line of the cylinder that accommodates both rotors. In addition, the point 8 is formed far away from the straight line connecting the rotation centers 3.4 of each rotor.The tooth profile mentioned above is defined as f/(m) as shown below, so (a) Compression Since the short-circuit leakage space (blowhole) between the chambers can be made virtually zero, and the tooth tip of the female rotor is made to match the pitch circle diameter, the female rotor tooth tip at the male mouth = evening tooth root portion is Eliminates interference and improves the shutoff effect. (l) By locating point 8 on the male rotor tooth profile far from the straight line connecting the rotation centers 3 and 4 of both the female and male rotors, low pressure is achieved. Since the space 18 created at the contact portion between the side end plate and the male rotor and the female rotor has a small volumetric expansion rate as the rotor rotates, there is little power loss due to the vacuum generation effect based on the volumetric expansion. On the other hand, the following problems have been pointed out: (C1 space volume is small (stroke volume is small). (d) The bottom of the female rotor tooth profile is uneven, so the sealing performance is not good. In addition, it is difficult to measure the dimensions during machining.Furthermore, the outer shape of the cutter becomes complicated, making it difficult to process.
The sealing points are easily worn and the sole effect is difficult to maintain. (F+ Since the pressure angle becomes almost equal to 0 near the pitch circle, it is difficult to machine the tooth profile with high precision, and the tool life will be shortened. Especially when hobbing screw rotors, the life of the hobbing tool will be shortened. Figure 1(a) shows the phase of the tooth profiles of both rotors immediately after point 8 of the male rotor tooth profile and curves 13 to 14 of the female rotor tooth profile of the rotor having the above-mentioned tooth profile start brush stroke.・1:1', and then the male rotor rotates about 20 degrees to reach the phase shown in Figure 1(b), but the contact surface indicated by 18' in Figure 1(a) is 1(b
) In the figure, it expands into a space like 18, so a vacuum space is created in this part, and the necessary power (unrelated to compression) is consumed, so it is preferable that the space volume does not become large. . The above-mentioned tooth profile has a small rate of volumetric expansion, so the power loss is small. For example, one of the conventional tooth profiles used by other companies, Tokuko Sho 56-1
The tooth profile of the rotor used in the screw rotor machine described in Publication No. 7559 is as shown in Figure 2 (a).
Structures with the same reference numerals as in the figure are the same sections. In Fig. 2, (1) Female rotor tooth profile (a) Advance side 28-29; Point on straight line 17-29: Arc with radius 1゛1 centered at 36. 2g -30: Solidity of radius r'2 centered on pinch point 17 +X. (B) Follower side 30-31; O-J゛Ebitrochoid curve formed by point 23 on the rotor tooth profile. 3]-32; A straight line passing through the rotation center 1 of the female rotor. 32-33; Arc having its center on the pitch circle 16. 3: 3-34: Circular arc centered on rotation center 4. 34--35 ; Pitch circle] An arc whose center is on 6. (2) Male rotor tooth profile (A) Forward side] 2]-22; Female rotor tooth profile A-29 (straight line 17-29
An envelope of a circular arc with radius r'1 centered at point 36 above. 22-23; Arc with radius r'2 centered on pitch point 17. (b) Follower side 23-24: Ebitrochoid curve formed by point 31 on the female rotor tooth profile. 24-45; Creation curve by straight line 31-32. 2.5-26; Arc with center on pitch P 5. 26-27; Arc centered on rotation center 3. 27-21; Middle upper and full arc on pitch circle 15. However, the capacity of the illustrated space (X empty space) 8 is larger than that of the tooth profile shown in the first figure. In addition, when both the female and male rotors are at the rotational position (/'C) shown in FIG. They are in contact with a slight clearance.The three contact points form a space 79 on the forward side of the tooth profile (above the X axis in the figure), while
A space 18 is similarly formed on the following side of the male rotor tooth profile (below the X-axis). Now, on the suction side end surface 74 (see Figure 3), as both the female and male rotors rotate in the direction of the arrow, the volume of the space I8 gradually expands, forming a significantly larger vacuum space as described above. do. On the other hand, on the discharge side end face 75 (see Figure 3), the space and fullness gradually decrease as the two rotors rotate, and eventually reach a point close to zero. It turns out. Therefore, the space 79
The gas trapped inside becomes abnormally pressurized, and in the case of an oil-cooled rotary compressor, lubricating oil is injected into the compression space for cooling, cooling, and lubrication in the closed space. remains, resulting in a state of fluid compression, which causes the female and male rotors to generate abnormal vibrations and noise, and in extreme cases accelerates rotor wear and damage. Additionally, K requires an excessive rotational torque and applies an excessive load to the rotor and casing, resulting in a large power loss, and still results in a shortened bearing service time. In order to solve the above-mentioned problems, the
As described in Japanese Patent Publication No. 4.693 and Japanese Patent Publication No. 58-131388 [see Figure 2(b)], a bypass hole 77 is bored in the inner wall surface 75 of the discharge side casing, and the bypass hole 77 is formed in the inner wall surface 75 of the discharge side casing. through 7 into a separate low-pressure working space or suction side space, or
Alternatively, measures have been taken to increase the volume of the bypass hole 77 to prevent it from flowing into the low-pressure working space, but the structure is complicated.1. ! However, there was a drawback that the cost was high. Purpose Therefore, the present invention solves the problems mentioned above without lacking the above-mentioned advantages of the tooth profile shown in the first drawing conventionally used by the present applicant, or by reducing the losses based on them as much as possible. In particular, it prevents wear of the seal points to prevent a reduction in efficiency over long-term use, and also prevents the wear of the seal points, which are formed on the inner wall surface of the discharge side casing when the discharge boat is closed just before the end of the discharge process. The purpose is to provide a new tooth profile that prevents abnormal vibrations and noise caused by the reduction of the closed space, ensures smooth and overload-free operation, and solves problems in forming and processing. That is. , :f: detailed configuration and effects will be made clear in the description of the embodiments below. Structure The present invention is a screw rotor consisting of a female rotor and a male rotor that rotate around two shafts (1-1) in full meshing, and the main part of the valley tooth profile of the female rotor is the same as that of the rotor. The main part of each tooth profile of a male rotor is formed outside the pitch circle of the same rotor.
Among the tooth profile curves formed in the plane perpendicular to the rotational axis of each rotor, at least the following tooth profile of the rotor runs from the tooth tip to the root side. A circular arc with a radius R1 centered at the male rotor's rotation center, sandwiching the center angle θ2 when looking at the straight line connecting the rotation centers of each rotor on one side, and a radial line connecting the end of the arc and the male rotor's rotation center. , is an ebicycloid curve created by the intersection of an arc of radius R4 inscribed in an arc of front straight radius R+ drawn with the center and a pitch circle of the same radius as the following side tooth profile curve of the female rotor, and,
The circular arc center position of the radius R4 is formed far away from the straight line connecting the rotation centers of each rotor, and the trailing side tooth profile of the female rotor is from the tooth bottom to the tooth tip side K fa and from the trailing side of the male rotor. A screw rotor comprising an envelope formed by a circular arc with a radius R4 forming a part of a tooth profile. 2. A screw I coater consisting of a female rotor and a male rotor that rotate in mesh around two parallel axes, and each tooth profile of the female rotor has a main part and a small part formed within the pitch circle of the same rotor. , each tooth profile of a male rotor is of a type in which the main part is formed outside the pitch circle of the same rotor, and in each tooth profile curve formed within a plane orthogonal to the rotation axis of each rotor, the tooth profile of a female rotor is The advancing side tooth profile has an apex at a position outside the pitch circle of the female rotor on a straight line connecting the rotation centers of each rotor along the tooth tip to tooth bottom side, and an angle of θ1 when looking at the straight line to one side. The tooth profile on the following side consists of a circular arc with a radius R2 that circumscribes a circular arc with a radius R3 drawn with the apex as the center, and a circular arc with the radius R3. From tooth tip side 1fC tears 5
, at least a curved line that falsely connects the arc of radius R3 and the envelope formed by the arc of radius R4 forming a part of the follower side tooth profile of male row 2', and the radius R1. The tooth bottom of the female rotor connects the arc of radius R3 and the envelope either side by side or by a common tangent, while the forward side of the male rotor The tooth profile is formed by an envelope formed by an arc of radius R2 of the forward tooth profile of the female rotor, and an envelope also formed by an arc of radius R3, moving from the tooth root to the tooth tip side. , The following side tooth profile overflows from the tooth tip to the tooth root side, and when the straight line connecting the rotation centers of each rotor is viewed on one side, the radius R centered on the rotation center of the male rotor, which is sandwiched by the center angle ゛θ2] an arc of radius R4 inscribed in the arc of radius R1, whose center is placed on a radius line extending from the rotation center of the male rotor to the other end of the arc of radius R1, and a tooth profile on the follower side of the female rotor. The center of an arc with a radius R71 that is formed by an evicycloid curve created by the intersection with the same pitch circle and forms a part of the following side tooth profile of the male rotor. One embodiment of the present invention will now be described with reference to the accompanying drawings. FIG. 3 shows a compressor for compressible fluid constructed by incorporating the screw rotor of the present invention, and FIG. 3(a) and FIG. 3(b)
Figure 3(b) is a cross-sectional view taken along the line BB in the same figure. In the figure, 1 is a male rotor that is rotated and driven by a rotating shaft 60V'c connected to a drive device (not shown), and is located at a χ-j symmetrical position with the rotor tooth groove surface shaft 60. The rotor 1 is rotatably supported by the bearing portions 64 and 65 of the respective Vi@i temporary 62 and 63 in cooperation with the support shaft 61 extending to the male rotor 1. A female rotor is engaged with the end plate 6 by means of a rotating member 1 extending on each end face thereof.
It is rotatably supported on three axes by 2.63. 66 is the rotor l upper\, h?, which is in mutual V mesh with the - pair. a casing surrounding the outer periphery of the low-pressure side section 11 having a suction [167] at its longitudinal end face;
2 and the high-pressure side end plate 63 provided with the discharge port 68'jf: are connected to the rotor tooth groove surface, the casing inner wall, and the inside of both lh1 plates, thereby forming and dividing an action space 69. The working space 69 has a suction port 67 and a discharge port 68 that communicate with a low pressure passage 70 and a high pressure passage 71, respectively, for a working fluid in the casing VC.
The cross section of 6 has two cylindrical spaces arranged in parallel, and the distance between their center axes is smaller than the sum of the radii of each cylindrical space, so both cylindrical spaces have mutually overlapping parts, and the inner walls of the subspaces intersect. A ridge line 72 appears in the portion. Female rotor? For example, each spiral groove is located in the (longitudinal) direction of the rotation axis, and has six vortices twisted around the axis (usually 200 mm), and the groove is located inside the pitch circle of the rotor.
The height of the teeth separating the grooves is equal to the pitch circumference, and the groove shape is a concave curve within the groove. The male rotor usually has four spiral teeth,
Both threads are along the rotation axis (longitudinal) direction, and the tooth length of the rotating β thread is located outside the pitch circle of the same rotor, and a female roller is inserted between both threads and the tooth thread. There is a groove for the grout to fit into,
Its tooth profile has a large, outwardly convex curve. The working space 69 is divided into a square shape, and after the rotation of the rotor closes the communication between the suction port 67 of the low-pressure side end plate 62 and the working space, the meshing line of both rotors moves (as the rotation of both rotors Due to the accompanying relative), the volume of the partitioned working space is reduced compared to that at the time of closure, and the compressible fluid in the working space, which has been adiabatically compressed and becomes high pressure and high temperature, will eventually reach high pressure. Discharge port 6 bored in side end plate 63
8 and is discharged to the high pressure chamber 71 side. During this time, the meshing between the rotor teeth and groove surfaces, the sliding surface between the inner wall of the casing and the sliding surface between the rotor end surface and the inner surface of both end plates, temperature control, O/airtight maintenance (sealing), and In order to cool the heat generated by the adiabatic compression of the compressible fluid, cooling lubricating oil is injected into the working space through the nozzle 73. ] Figures 4(a) and +b1 show the tooth profile curves of each rotor seen when the screw rotor is cut along a plane perpendicular to each rotation axis. In the middle, ■ is the male rotor, 3 is the rotation center of the rotor, 15 is the pitch circle of the rotor, and the male rotor l rotates in the direction of the arrow around the rotation center 3. The child meshes with the male rotor. It is a female rotor, and rotates in the direction of the arrow around the rotation center 4. 16 is the pitch circle of the female rotor, and the pitch circle is 3.4 at the top during rotation.
It touches the pitch circle 15 on the straight line connecting the lines. Pitch circle 15.
16 contact points are pitch points 17. Both pitch circles 15.1
The diameter ratio of 6 is 2/3. Note that this is a space close to a vacuum created at the contact portion. 4th mountain) Referring to the diagram, (1) Tooth profile curve of female rotor a) Forward side tooth profile, extending from the tooth tip to the tooth bottom side, (at 4
Between 7 and 48 (ha; Center of rotation - center point 5 of an arc of radius R3 that is on the straight line connecting 3 and 4 and is outside the pitch circle 16
2) Angle θ between the vertex and the straight line, = 40° to 46
An arc of radius R2 that circumscribes an arc of radius R3, drawn with the entire center of point 53 on a straight line sandwiching °. (b) Between 48 and 4.9 is an arc 01 PCD of a central angle θ1-40 to 46 drawn with a radius R3 centered on the point 52; the pitch circle diameter of the male rotor is 3 IJ-17°; The larger 1 is, and the smaller θ1 is, the larger the pressure angle near the pitch circle of the tooth profile curve composing 48-49e can be, making it easier to form the tooth profile with a hob, and the smaller θ1 is. The larger the number, the thicker the tooth profile of the female rotor can be. In this example, the pressure angle was set to a range in which a sufficiently large tooth thickness and sufficient strength could be ensured, and θl and R3 were determined as described above. (0) Follow-up Lateral tooth profile, from the root to the tip, tc+
49-51 interval: An arc with a radius R+ (344,) centered on the rotation center 3 of the male rotor ↓ has a center angle θ2-4 ~
8 is stretched, an envelope formed by arc 44-45 on the tooth profile curve drawn with radius R4 centered on point 54 on radius line 3-44. fd) 50-50 is on the straight line connecting the envelope 49-51 formed by the circular arc 44-45, which is a part of the tooth profile curve of the male rotor, and the rotation centers 3 and 4, and the center 52 is located outside the pitch circle 16. common tangent with radius R3 arc 48-49,
Note that the interval between 50 and 50 may be smoothly connected using a gentle curve similar to the arc of radius R1. (e) Between 51 and 47 is the circumference of the pitch circle 16. (2) Tooth profile curve of male rotor A) Forward side tooth profile, sloping from the root to the tip side, 1 ridge) Between 4'1-42 (A; Arc 47-48 on the tooth profile curve on the female rotor's side) Envelope between fg+ 42 and 43: Envelope by arc 48 and 49 on the tooth profile curve on the female rotor side, zero * 0 (B) Follower side tooth profile, from the tooth tip to the tooth root side, Y) 43
-44 is a circular arc with a center angle θ2-4 to θ2-8 centered on the center of one rotation 3 and drawn with a radius R1. The larger θ2 is, the smaller the space ]8 can be, and θ
The smaller 2 is, the smaller the gap between the male and female rotors between 43-44 and 50-50 can be. In this embodiment, the space 18 can be made sufficiently small, and the gap between the male rotor and the female rotor between the curves 43-44 and 50-50 can be made within a range that does not pose a practical problem, and θ2 is The above figures have been determined. fi) Between 44 and 45; An arc of radius R4 centered on point 54 having a center on radius 3-44. In relation to the value of θ2 in the tooth), the position of the center point 54 of the circular arc with radius R4 is set far away from the straight line 3-4. fj) Between 45 and 46; female rotor? Tooth profile curve 49-
51 and pitch circle 1G. (k) Between 46 and 41 is the pitch circle of the male rotor]5. As an example, each radius and angle in the tooth profile shown in FIG. 4 is shown in Table 1. Table 1. However, P CD : Pitch diameter effect of male rotor Since the tooth profile curve of the screw rotor of the present invention is as described above, under the conditions of (1) (h) and fi), (a) radius R
By providing the entire center point 54 of the arc 44-45 of No. 4 on the radius line 3-44 extending from the rotation center 3 of the male rotor↓, the arc 44-4 at the point 44 as shown in FIG.
The angle θ5 between the tangent to 5 and the perpendicular 1 to the line 3-4 passing through the points is the radius line 17 extending from the center point 7.
- It can be made smaller than θ5 when provided on 44, and the male rotor's following side tooth profile curve is far away from the straight line 3-4 connecting each rotation center, and the female rotor's following side tooth profile curve is soon published. It can be made smaller than the vacuum creation space 18. (b) In the conventional tooth profile shown in FIG. 2(a), just before the end of the discharge process and when the discharge port is closed, the seven spaces formed on the forward movement side of the male rotor are The volume decreases accordingly. Therefore, the space 79
The compressed gas and/or lubricating oil trapped inside are abnormally pressurized. In the cylindrical case of the present invention, a space corresponding to the space 79 is generated in the compression process, but the lines 44 to 45f of the male rotor tooth profile form an angle θ2 (~ 4 to 8), and the center 54 is located on the radius 13-44 that intersects with the center line 13-44. The line 50-50 of the female rotor tooth profile is a common tangent between the envelope formed by the arcs 44-45 of the male rotor tooth profile and the arc of radius R3, or the radius R1.
It is a gentle curve similar to that of the male rotor tooth profile line 42.
Since -43 is the envelope formed by the circular arcs 48-50 of the female rotor tooth profile, the confined volume of the space can be made as small as possible. Furthermore, on the discharge side end surface, a portion formed by the envelope of both tooth profiles as both rotors rotate -JL'l:if
The space is communicated with the suction side. As a result of the above, when the discharge port of MfJ is closed immediately after the discharge process is completed, over-compression of compressed air and liquid compression within the space are eliminated, and the accompanying noise and abnormal vibrations are eliminated. Also, unexpected wear, bearing wear, etc. do not occur.Furthermore, the prior art proposed in the widely used Japanese Patent Application Laid-Open No. 58-214
It is not necessary to provide the Ibus hole 7 '7 Ci2 fi3) as described in the 693 publication and the Japanese Patent Application Laid-Open No. 1983-131383, and the structure is simple and inexpensive.
Our goal is to provide a screw compressor that is highly efficient. E'I Same figure
Center 54f of the circular arc: By forming it far away from the straight line 3-4, the space 18 can be further reduced. That is, while both rotors rotate from the phase shown in FIG. 4ia1 to the phase shown in FIG. 4(b) (C1 space 1
80 Since the rate of volumetric expansion is relatively small, there is little power loss due to vacuum creation. (2) Due to the conditions in (j), the blowhole is narrow enough to pose no problem in practice, as shown in Figure 9 ().In the figure, members with the same symbols as in Figure 4(b) is the same as that shown in the same figure and has the same function and effect, so the explanation will be omitted. 72 is the casing 66
It is the ridgeline where the two cylindrical space surrounding walls intersect,
It is also the point where the teeth of both rotors mesh. (3) Based on the conditions of tc) above, as shown in Figure 5,
(a) Out of the tooth profile curve of the male rotor J, the envelope curve of the arc 44-45 with the radius R4 is the female rotor? The tooth profile curve 49-51 improves wear resistance compared to a male rotor tooth profile where the same point becomes an inflection point.
Maintain the original compression efficiency over a long period of time. 1:11+ When lubricating oil E is supplied to 1 between the contact surfaces with 44-4, 5 and 49-51, the sliding surfaces curve in the same direction, so due to the sliding A wedge effect can be created to improve the lubrication and/or lubricating properties of the surface. (4) From the conditions in (1) above, (a) Conventionally, important points as /-ru points [point 8 on the tooth profile curve in Figure 1(b), point 8 on the tooth profile curve in Figure 2(a)] Point 2
[Refer to 3] However, because it was a discontinuous point, it was difficult to accurately measure the position and it was difficult to process with high precision. Since they are connected smoothly, the position can be easily measured and processed with high precision. By eliminating the discontinuous points on the tooth profile curve, it becomes easier to manufacture the cutter, and the service life of the tool can also be extended. (5) Based on the conditions in (b), as shown in Figure 6,
The angle θ3 between the tangent to the tooth profile curve at point 48 and the straight line connecting the rotation center 4 and point 48 of the female rotor is at an approximate point on the arc of radius 17-49 drawn with the pitch point 17 as the center. Since it can be made larger compared to 03, the pressure angle near the pitch circle of the tooth profile curve that makes up all curves 48-49 becomes larger, which improves the machining accuracy of the tooth profile and extends the tool life. becomes possible. (6) According to the condition (a) above, the center point 53 of the arc 47-48 is on the same side as the center point 52 of the arc 48-49 (if compared to Referring to the figure, since the angle θ4 between the straight line tangent to the curve at point 47 on the arc 47-48 and the straight line connecting the rotation center 4 of the female rotor and the point 47 can be increased, the angle θ4 of the arc 47-48 can be increased. The pressure angle near the pitch circle can be increased,
Effective in improving machining accuracy and tool life. (7) From the above conditions) and +g), fa) and fb
Coupled with the conditions of ), (a) wear resistance can be improved by forming an envelope of circular arcs 47-4, 8, and 48-50. (b) When lubricating oil is interposed between the rain shelter surfaces, the lubricating oil creates a wedge effect due to the sliding of the contact surfaces, as shown in Figure 5, which improves the lubricating effect on the surfaces and the sealability. can. As detailed above, according to the first invention of the present application,
Radius R centered at the center of rotation of the male rotor, with the following tooth profile of the male rotor running from the tooth tip to the root side, and sandwiching the corner of the center angle θ2 when viewed from one side of the straight line connecting the rotation centers of each rotor.
] and has a center on a radius line extending from the rotation center of the male rotor to the other end of the arc, and has a radius 1 (1
An arc of radius R4 drawn to be inscribed in the arc of The tooth profile of the female rotor on the trailing side is formed at a position far away from the straight line connecting the rotation centers of each rotor, and the trailing side tooth profile of the female rotor is moved from the tooth bottom to the tooth tip side to form a part of the trailing side tooth profile of the male rotor. Since the envelope is formed by the arc of radius R4, when the two rotors rotate in unison, the suction side end plate and the male and female 1lJ-
The space (vacuum creation space) created at the contact area with the vacuum cleaner can be made smaller, the power loss due to the vacuum creation can be completely reduced, and short-circuit leakage spaces (blow poles) can be virtually eliminated. The lubricating oil applied to the contact surface of the tooth profile curve on the follower side tooth profile of the screw rotor produces a wedging effect as the contact surface slides. It is possible to improve the wetability and sealability, and the durability of the sliding surface can also be improved. Yes, this is the second invention of the second application. On the connecting straight line, the position outside the pitch circle of the female rotor is the apex,
When the straight line is viewed on one side, the center is on an extension of a straight line that sandwiches an angle of 7. The forward tooth profile of the male rotor is drawn from the tooth base to the tooth tip side, and is formed by an envelope formed by an arc of radius R2 and a circular arc of radius R3 of the forward tooth profile of the female rotor, so that the suction side During meshing rotation between the end plate and the male and female rotors, the space (vacuum creation space) created at the contact portion of the tooth profile curve can be reduced, reducing power loss due to the vacuum creation. (In addition, short-circuit leakage spaces (blow holes) can be virtually eliminated, and the wedge effect of the lubricating oil supplied to the sliding surfaces of the screw rotor on the trailing side tooth profile and the advancing side tooth profile causes the above-mentioned It achieves both the warmth properties of the sliding surface and the sole properties, and prevents abnormal vibrations and noises that occur when the discharge port is closed immediately before the end of the discharge process on the inner wall surface of the discharge side casing, and also prevents noise near the pinch circle. By increasing the pressure angle, it is possible to form a tooth profile with excellent workability, thereby making hobbing easier and, moreover, extending the life of the tool.As described above, according to the present invention, in practical use It is possible to provide a useful screw RL. 4 Brief explanation of the drawings FIGS.
The tooth profile curve of the rotor, FIG. 1(a) and FIG. 1(b)
The figure shows a case where the meshing phase of a pair of rotors is different based on the tooth profile used by the present applicant, Figure 2 (a) is an example of the tooth profile used by another company, and Figure 2 (b) (d) shows an example of the tooth profile used by another company. Partial sectional view of the discharge side cylinder of the role, Figure 3 (a) and Figure 3 (b)
) Figures 4(a) and 4(a) show a side sectional view and a cross sectional view of a screw rotor according to the present invention.
b) The figure shows the tooth profile curves of a pair of rotors of the screw rotor according to the present invention. A drawing showing a part of the tooth profile for explaining the curve, and Fig. 9 is a diagram explaining the presence or absence of blowholes in the scringe rotor of the present invention. J Male D-ta, ?...Female rotor, 3 and 4...
Rotor rotating upper middle, 15 and 6 pitch circle, 18X
empty space. Agent Patent Attorney Eiji 1) Hiroshi - Figure 2a, Figure 2b, Figure 3a, Figure 4b/Figure 9

Claims (1)

[Claims] 1. A screw rotor consisting of a female rotor and a male rotor that rotate around two parallel axes in mesh with each other, and each tooth profile of the female rotor has a main portion within the pitch circle of the same rotor. Each tooth profile of a male rotor is of the type in which the main portion is formed outside the pinch circle of the same rotor, and each tooth profile formed in a plane perpendicular to the rotation axis of each rotor has at least The following tooth profile of the male rotor is
An arc of radius R+ centered at the rotation center of the male rotor, which is dipping from the tooth tip to the root side VC and sandwiching the center angle θ, 2 when looking at one side from the straight line connecting the rotation centers of each rotor. On the radial line extending from the rotation center of the rotor, an intersection point is created between an arc of radius R4 inscribed in the arc of radius R1 drawn with the center at the center, and the follow-up side tooth profile curve of the female rotor and the pitch circle of the same rotor. The shape is similar to the cycloid curve, and the arc center position of the radius R4 is formed far away from the straight line connecting the rotation centers of each rotor. A screw rotor comprising an envelope formed by a circular arc having a radius R4 that extends from the tip to the tooth tip side and forms a part of the following side tooth profile of the male rotor. 2 A screw rotor consisting of a female rotor and a male rotor that rotate while meshing the circumferences of two parallel axes, in which each tooth profile of the female rotor has its main portion formed within the pinch circle of the same rotor, and Each tooth profile of the rotor is of a type in which the main part is formed outside the pitch circle of the same rotor, and among the tooth profile curves formed in the plane orthogonal to the rotation axis of each rotor, the tooth profile on the forward side of the female rotor On the straight line that runs from the tooth tip to the tooth bottom side and connects the rotation center of each rotor, the pitch circle of the female rotor has its apex at the outer position, and when looking at the straight line on one side, θ1 is The tooth profile on the following side consists of an arc with a radius R2 circumscribing an arc with a radius R3 drawn with the apex as the center, and an arc with the radius R3, which has its center on an extension of a straight line that pinches the corner. Lives from the root of the tooth to the tip of the tooth,
At least a curve that falsely connects the circular arc with the radius R3 and an envelope formed by the circular arc with the radius R4 forming a part of the following tooth profile of the male rotor, and the circular arc with the radius R4. On the other hand, the forward tooth profile of the male rotor is formed by the envelope line of radius R2 of the forward tooth profile of the female rotor from the root to the tooth tip, and the same radius. The following tooth profile is formed by the envelope line formed by the circular arc of R3, and the following side tooth profile is formed by the following tooth profile along the tooth tip to the tooth root side, with the straight line connecting the rotation centers of each rotor on one side, and the center angle θ2 sandwiched therebetween. An arc of radius R1 centered on the rotation center of the rotor, and a radius R4 inscribed in the arc of radius R+ drawn with the center on a radial line extending from the male rotor rotation center to the other end of the arc of radius R+. It consists of an ebicycloid curve created by the intersection of a circular arc and the following side tooth profile of the female rotor and the same pitch circle, and the tracking position of the male rotor is set far away from the straight line connecting the rotation centers of each rotor. A screw rotor characterized by being formed by