JPS63248992A - Rotor of rotary type blower - Google Patents

Abstract

PURPOSE:To prevent the air leak between a housing and a rotor by forming the part most remote from the revolution center of the rotor and the closest part into a circular arc form having each revolution center point as center. CONSTITUTION:As for the outer shape of a rotor 20, the part between the cross point (a) with a Y-axis and the point (b) is a small circular arc 22 having a radius (r) with the revolution center point O as center, and the angle theta is nearly equal to the angle alpha. The part between the points (b) and (c) is an envelope curve 24, and the point (c) is on the extension line drawn at the angle of about 45 deg. (beta) for the X axis from the point O. Further, the part between the points (c) and (d) is a circular arc 26 drawn with the radius qR and the position pR (point f) on the X axis similar in case of the Root's type in the prior art. The part between the points (d) and (e) is a large circular arc 28 having a radius of Rz. The angle alpha is within a range of 3-30 deg., and the value L for setting alpha within the range is previously set, and the following relation is generated: L/R<=1.2. When the outer shape of the rotor is formed in such a form, air leak between a housing and the rotor is prevented by the large circular arc 28, and the air leak between the rotors can be prevented by the small circular arc 22, and discharge efficiency can be improved.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to a rotor for a rotary blower, and in particular to a rotor for a rotary blower that reduces air leakage from the gap between the outer peripheral surface of the rotor and a housing to improve discharge efficiency. Regarding the rotor of a type blower.

[Description of Prior Art] Rotary blowers used in compressors, compressors, etc. are classified into Wankel-type rotary blowers and Roots-type rotary blowers, depending on the external shape of the rotor.

The external shape of the rotor of a Wankel type blower consists of a large semicircular arc part for sliding contact with the wall surface of the housing, a small semicircular arc part for contacting the large arc part on the other side, and these large arc parts. It consists of a straight part for connecting the small arc part. In this Wankel type rotor, the large circular arc portion is shaped to come into contact with the inner wall of the housing, thereby ensuring airtightness at the location where the rotor contacts the housing wall surface.

In this Wankel type rotor, two points of contact between the rotors simultaneously come into contact when the rotor rotates, so a space is created that is sealed by these two points of contact, and the air in this space is sucked in instead of being sent out to the discharge side. There was a drawback that the liquid was pushed back to the side, resulting in lost volume and poor discharge efficiency. If this loss volume is large, there is also the disadvantage that the temperature of the blower itself increases and the noise increases.

There are various roots type rotors that eliminate this loss volume, and an envelope rotor using an envelope curve is one of them.

The external shape of this envelope rotor is, for example,
As shown in No. 0-75793, the outer shape close to the rotor's center of rotation is an envelope curve, and the outer shape far from the rotor's center of rotation is an arc (the center of this arc is different from the rotor's center of rotation), and these envelope curves and a circular arc connected together. Here, as an example of a conventional envelope rotor, a bilobal envelope rotor is used as a fourth rotor.
The length 2R between each rotating shaft shown in the figure is set in advance. The arc 12 of the rotor 10 is a part of a circle drawn with a radius qXR and centered at a position pXR away from the rotation center '+7+O of the rotor. Also, the distance from the rotation center of the rotor to the longest end of the rotor is Ro=pR+qR...(1).The relationship between these p and q is q, which is the known basic relational expression for envelope rotors. = 1 + p2-, E
p x co sβ...(2), β=90°/n・
...(3) [In case of n-leaf rotor]

Here, when Ro is determined, p and q are calculated from the equation (1), equation (2), and equation (3). Here, if n=2 in equation (3), p and q of the two-lobed rotor 10 are calculated and the arc 12 of the rotor 10 is drawn.

On the other hand, the envelope curve 14 is obtained from a conventionally known basic relational expression, and a description of the calculation of the relational expression will be omitted here. As shown in Fig. 5, this envelope curve is located at the circular arc near the extension line extending from the center of rotation at an angle of approximately 6 degrees to the long axis 12.

It is known that in an envelope rotor (roots type rotor) having such a configuration, the circular arc 12 of one rotor and the envelope curve 14 of the other rotor contact at one point, so no loss volume occurs. ing.

[Problems to be solved by the invention] However, since the arc in the conventional envelope rotor is an arc centered at a position different from the rotation center of the rotor, the rotor comes into line contact with the nodding ring. However, there was a problem in that airtightness between the rotor and the housing could not be ensured at this contact point.

[Objective of the Invention] The present invention has been made in view of the above points, and improves discharge efficiency by eliminating air leakage from the contact surface between the rotor and the housing while preventing loss volume from occurring. The present invention provides a rotor for a rotary blower.

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a rotor for a rotary blower having an outer periphery including an envelope curve and an arc centered at a position different from the rotational center point of the rotor. ,
The point farthest from the center of rotation of the rotor is an arc centered on the center of rotation of the rotor, and the point closest to the center of rotation of the rotor is an arc centered on the center of rotation of the rotor.

[Operation] The farthest point from the rotational center of the rotor is defined as a large circular arc centered on the rotor's rotational center.

Since this circular arc makes surface contact with the wall surface of the housing, airtightness between the rotor and the housing can be ensured.

Further, the point closest to the rotor's rotational center point is a small circular arc centered on the rotor's rotational center point, and the small circular arc and the large circular arc prevent air leakage between the rotors.

[Example] Next, the present invention will be explained based on the drawings.

FIG. 1 is a side view showing a quarter (first quadrant of coordinates) of a two-lobed rotor that is an example of a rotary blower according to the present invention. Let the rotation center O of the rotor 20 be the intersection of the X-axis and the Y-axis. The entire outer shape (not shown) of this rotor 20 is as follows:
The outer shape shown in FIG. 1 is made symmetrical about the X axis, the Y axis, and the intersection point O, so that the entire shape forms one loop curve.

That is, the outer shape of the rotor 20 is symmetrical with respect to two axes, the X-axis and the Y-axis, which are perpendicular to the rotation axis.

The external shape of the rotor 20 is formed by connecting each point abcde from the intersection with the Y axis to the intersection with the X axis in FIG. First, the intersection with the Y axis is defined as point a, and from point a to point b is a small circular arc 22 with radius r (its calculation will be described later) centered on rotation center point O. The angle 0 of the small arc 22 from point a to point b is approximately the same as the angle α from point d to point e, which will be described later.

From point b to point 0, there is a conventionally known envelope song that connects those points b and 0! 1j24. This 0
The point is approximately 45° from the center of rotation O to the X or Y axis.
It is assumed to be on or near the extension line drawn at an angle of (β). The distance from point 0 to point d is the same as the locus of an arc 26 drawn with radius qR centering on the position pR (point f) on the X-axis, similar to the conventional roots-type rotor.

The distance from point d to point e is a large circular arc 28 having a radius Rz centered on the rotational center point 0 of the rotor. d of this great arc 28
The angle α between the point and the e point is in the range of 3″ to 30°, and the chord value (the height of the Y axis at the d point is L/2) is set so that α is within that range. A value is arbitrarily set in advance.This L is set such that L/R≦1.2.

Here, as shown in FIG. 2, if g is the intersection of a line drawn from point d perpendicularly to the X-axis and the X-axis, then the radius Rz is determined by the Pythagorean theorem. Here, award = L/2.6
1°=PR and f g= (qR)2-(L/2)
Since it is 2.

From these values, Rz is expressed as follows. Since P, q, and R are known, the value of Rz can be calculated, and the great circular arc 28 from point d to point e can be drawn. The inner wall of the housing has a radius Rz centered on the rotational center point of the rotor.
is formed.

From this R2, the radius r from the point a to the point b is determined. That is, the radius r is the distance between the rotors.

Distance #2R minus radius R2 of large arc 28 r = 2R-
Rz.

This Rz is the maximum length Ro of the conventional envelope rotor.
= pR + qR.

Moreover, Ro to be set in advance is 1.1≦Ro
/ R≦1.9.

Here, the reason for limiting the range of each numerical value mentioned above will be explained. First, set the angle α of the arc from point d to point e from 3° to 30
Set to ″″. This is because when α is less than 36, the airtightness cannot be maintained and the rotary blower cannot exhibit its effectiveness.On the other hand, when α exceeds 30°, the cross-sectional area of the rotor becomes large and the discharge amount decreases. This is because the disadvantage is that the loss volume becomes large.

Next, the relationship between the length L of the large arc in the Y-axis direction and half R of the distance between the axes was set to L/R≦1.2. This means that L/R is 1.
This is because when it becomes larger than 2, α becomes large and a large loss volume occurs.

Furthermore, the apparent maximum length of the rotor Ro=pR+ql(
For H, which is half of the distance between the axes, the ratio is 1.1≦R
o/R≦1.9.

This becomes 1.1>Ro/R (habo l=Ro/R).
When it becomes R), the rotor shape becomes a perfect circle.

The discharge amount becomes O. On the contrary, Ro/R>1
．． When it becomes 9 (when Ro/R=2), the maximum diameter of the rotor and the distance between the shafts approach the same, so the rotor is no longer valid.

A characteristic diagram combining these elements is shown in Figure 3.
The diagonally shaded portion surrounded by the bold line in this characteristic diagram satisfies all of the above conditions. Here, the radius Rz of the large arc 28 from point d to point e is determined in the following order. First, assuming that the rotor interaxial pressure #, 2R is set, 1.
RO is set so that 1≦Ro/R≦1.9. By setting R and Ro, p,! from the above equations (1), (2), and (3). Find -q. Next, L is set so that L/R≦1.2 and the angle α is 31 to 30''. Rz is determined from these P, q, and L.

This large arc 28 contacts the small arc 22 during rotation. The large arc 28 also matches the inner wall of the housing. Since this large arc 28 makes wide contact with the inner wall of the housing, the contact area prevents air leakage.

Here, the radius of the area from point a to point b is r=2R−Rz
The reason why this area is made into an arc of radius r is to avoid that if this area is made into an envelope curve instead of being made into an arc of radius r, the gap between the rotors will become large and the discharge efficiency will deteriorate.

Although r and Rz were set to ideal values with no gap between the rotors, in reality, a gap occurs between the rotors, so even if a is within the range that takes the gap into account, it falls under the present invention. .

In addition, in the above embodiment, the rotor has two blades, but it has three blades.
It can be applied even to more than leaves.

[Effects of the Invention] As described above, according to the rotor of a rotary blower according to the present invention, the rotor has an envelope curve and an arc centered at a position different from the rotation center of the rotor. The farthest point from the rotation center point is an arc centered on the rotation center point, and the closest point from the rotation center point is an arc centered on the rotation center point. It is possible to prevent air leakage between the rotor and the rotor, thereby improving the discharge efficiency.

Furthermore, by forming small arcs corresponding to the large arcs, air leakage between the rotors is prevented and discharge efficiency is improved.

[Brief explanation of drawings]

FIGS. 1 and 2 are side views showing a quarter-quarter (first quadrant of coordinates) of a rotor of a rotary blower according to the present invention,
Fig. 3 is a characteristic diagram showing the range that satisfies various elements that match the rotor of the present invention, Fig. 4 is a side view of the main part of an envelope rotor, and Fig. 5 is a quarter-section of a conventional envelope rotor. FIG. 3 is a side view showing a portion (first quadrant of coordinates). 20...Rotor, 22...Small arc, 24...Envelope curve, 26...Circular arc, 28...Large arc, P. ...constant, q...constant, RO...constant, L...chord of the great arc, Rz...radius of the great arc. Figure 1 Y Figure 2 Figure 3 Figure 4 Figure 5

Claims (3)

[Claims] (1) In a rotary blower rotor that has an outer circumference that includes an envelope curve and an arc centered at a position different from the rotation center point of the rotor, the point farthest from the rotor rotation center point is the rotor rotation center point. A rotor for a rotary blower, characterized in that the rotor has a circular arc centered thereon, and a point closest to the rotational center of the rotor is an arc centered on the rotational center of the rotor. (2) The angle of the arc at the farthest point from the center of rotation is in the range of 6° to 60°, and the ratio of the chord L of the arc to half R of the distance between the rotors' axes is L/R≦1. 2, and the radius Rz of the arc is Rz=√{(qR)^2+2pR√[
(qR)^2-(L/2)^2]+(pR)^2} (p, q are found from the basic formula of the rotor), pR+q
A rotor for a rotary blower according to claim 1, wherein the ratio of R=Ro to R is 1.1≦Ro/R≦1.9. (3) Radius r of the arc closest to the rotation center point
is close to r=2R-Rz, and the angle of the arc is 6°
A rotor for a rotary blower according to claim 1, characterized in that the angle is within a range of 60 degrees.