Roots blower with improved clearance between rotors
First Claim
1. A Roots blower having a plurality of rotors, each of said rotors having a center, an orthogonal short and a long axes and a contour shape offset from a basic profile curve, the improvement in said blower wherein:
- said basic profile curve is a combination of epicycloidal curves and hypocycloidal curves, andsaid contour shape offset is defined by an equation;
space="preserve" listing-type="equation">L=L1+L2 (sin 2θ
).sup.nwhere;
L is a value of said contour offset;
θ
is an angle relative to a coordinate axes of a rolling circle of said cycloidal curve;
L1=Smin 0×
1/2, where Smin 0 is a clearance when said rolling circle angle θ
=0 degrees;
L2=(Smin 45-Smin
0)×
1/2, where Smin 45 is the clearance when the rolling circle angle θ
=45 degrees; and
n is an exponent.
1 Assignment
0 Petitions
Accused Products
Abstract
A Roots blower has two rotors in which each of said rotors, as viewed in plan view thereof in the direction of the rotational axis thereof. The rotor has a center and orthogonal short and long axes and has a final shape of a contour offset from a basic profile curve by an offset distance at every point thereof in the normal line direction thereto. The offset distance is also determined in accordance with a function which assumes a maximum value when the angle between a line connecting the rotor center with the point and either of the short and long axes is 45 degrees, which assumes a minimum value when the line coincides with either of the short and long axes, and the function comprises an exponential power of a sine function.
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Citations
2 Claims
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1. A Roots blower having a plurality of rotors, each of said rotors having a center, an orthogonal short and a long axes and a contour shape offset from a basic profile curve, the improvement in said blower wherein:
-
said basic profile curve is a combination of epicycloidal curves and hypocycloidal curves, and said contour shape offset is defined by an equation;
space="preserve" listing-type="equation">L=L1+L2 (sin 2θ
).sup.nwhere; L is a value of said contour offset; θ
is an angle relative to a coordinate axes of a rolling circle of said cycloidal curve;L1=Smin 0×
1/2, where Smin 0 is a clearance when said rolling circle angle θ
=0 degrees;L2=(Smin 45-Smin
0)×
1/2, where Smin 45 is the clearance when the rolling circle angle θ
=45 degrees; andn is an exponent.
-
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2. A Roots blower having a plurality of rotors, each of said rotors having a center, an orthogonal short and a long axes and a contour shape offset from a basic profile curve, the improvement in said blower wherein:
-
said basic profile curve is a combination of epicycloidal curves and hypocycloidal curves, and said shape is defined by a contour curve expressed by equations
space="preserve" listing-type="equation">X2=x-{L1+L2(sin 2Θ
).sup.n }sin ω
space="preserve" listing-type="equation">Y2=y+{L1+L2(sin 2Θ
).sup.n }cos ωwhere; X2, Y2 are coordinate axes values at a point on the epicycloidal and hypocycloidal curves; X, Y are coordinate axes values at a point on the epicycloidal and hypocycloidal curves; Θ
is an angle relative to a coordinate axes of a rolling circle of said cycloidal curve;L1=Smin 0×
1/2, where Smin 0 is a clearance when said rolling circle angle Θ
0 degrees;L2=(Smin 45=Smin
0)×
1/2, where Smin 45 is the clearance when the rolling circle angle Θ
=45 degrees;n is an exponent; and ω
=tan-1 (dy/dx), a tangent angle at said point x, y of said coordinate axes.
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Specification